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Vol. 49 N° 18 - Septembre 2010 [texte imprimé] . - 2010 . - p. 8289-8876 : ill. ; 28 cm. Chemical engineering Langues : Français (fre)
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Ajouter le résultat dans votre panierNanostructures with animal-like shapes / Boris I. Kharisov in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010)
Titre : Nanostructures with animal-like shapes Type de document : texte imprimé Auteurs : Boris I. Kharisov, Auteur ; Oxana V. Kharissova, Auteur ; Miguel Jose-Yacaman, Auteur Année de publication : 2010 Article en page(s) : pp. 8289–8309 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanostructures Résumé : Rare nanostructures having shapes of animals are discussed in detail. Nanoforms, such as nanolarvae, nanoworms, nanosquamae, and nanourchins, of mainly inorganic compounds are examined. These nanostructures possess numerous useful properties (such as magnetic, semiconducting, and field-emitting properties) and applications, including mainly catalytic processes (in particular, for photodegradation of organic compounds); creation of nano/biomaterials and solar cells; and treatment of tumors, among other uses. A nonformal classification for nanostructures based on rare nanostructures is offered. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100921q
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8289–8309[article] Nanostructures with animal-like shapes [texte imprimé] / Boris I. Kharisov, Auteur ; Oxana V. Kharissova, Auteur ; Miguel Jose-Yacaman, Auteur . - 2010 . - pp. 8289–8309.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8289–8309
Mots-clés : Nanostructures Résumé : Rare nanostructures having shapes of animals are discussed in detail. Nanoforms, such as nanolarvae, nanoworms, nanosquamae, and nanourchins, of mainly inorganic compounds are examined. These nanostructures possess numerous useful properties (such as magnetic, semiconducting, and field-emitting properties) and applications, including mainly catalytic processes (in particular, for photodegradation of organic compounds); creation of nano/biomaterials and solar cells; and treatment of tumors, among other uses. A nonformal classification for nanostructures based on rare nanostructures is offered. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100921q Exemplaires
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Titre : Fe/meso-Al2O3 : an efficient photo-fenton catalyst for the adsorptive degradation of phenol Type de document : texte imprimé Auteurs : K. M. Parida, Auteur ; Amaresh C. Pradhan, Auteur Année de publication : 2010 Article en page(s) : pp. 8310–8318 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Mesoporous Résumé : A series of Fe(II)/meso-Al2O3 catalysts was prepared by the wetness impregnation method using ferrous sulfate and mesoporous alumina. Mesoporous alumina was synthesized at pH 6 by the precipitation method using aluminum isopropoxide as the aluminum source and sucrose as the template. These catalysts were characterized by different techniques such as SEM, XRD, XPS, FTIR spectroscopy, and BET surface area analysis. The catalytic activities in phenol degradation by the photo-Fenton reaction were evaluated. The effects of H2O2 concentration, pH, and additive (ethanol) on the photo-Fenton reaction were studied. The sample with 0.25 wt % Fe(II)/meso-Al2O3-6 was found to be an efficient catalyst, showing 98% degradation of 2.1 × 10−5 mol of phenol at pH 6 in 1 h. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902049s
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8310–8318[article] Fe/meso-Al2O3 : an efficient photo-fenton catalyst for the adsorptive degradation of phenol [texte imprimé] / K. M. Parida, Auteur ; Amaresh C. Pradhan, Auteur . - 2010 . - pp. 8310–8318.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8310–8318
Mots-clés : Catalyst Mesoporous Résumé : A series of Fe(II)/meso-Al2O3 catalysts was prepared by the wetness impregnation method using ferrous sulfate and mesoporous alumina. Mesoporous alumina was synthesized at pH 6 by the precipitation method using aluminum isopropoxide as the aluminum source and sucrose as the template. These catalysts were characterized by different techniques such as SEM, XRD, XPS, FTIR spectroscopy, and BET surface area analysis. The catalytic activities in phenol degradation by the photo-Fenton reaction were evaluated. The effects of H2O2 concentration, pH, and additive (ethanol) on the photo-Fenton reaction were studied. The sample with 0.25 wt % Fe(II)/meso-Al2O3-6 was found to be an efficient catalyst, showing 98% degradation of 2.1 × 10−5 mol of phenol at pH 6 in 1 h. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902049s Exemplaires
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Titre : Thermal stability and isomerization mechanism of exo-tetrahydrodicyclopentadiene : experimental study and molecular modeling Type de document : texte imprimé Auteurs : Sun Hee Park, Auteur ; Cheong Hoon Kwon, Auteur ; Joongyeon Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 8319–8324 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermal stability Résumé : Thermal stability and the primary initiation mechanism of exo-tetrahydrodicyclopentadiene (exo-THDCP, C10H16) were investigated in a batch-type reactor. The catalytic role of the stainless steel inside the reactor was eliminated by inserting a quartz flask. exo-THDCP decomposed at temperatures over 623 K and 1-cyclopentylcyclopentene (1-CPCP, C10H16) and 4-methyl-2,3,4,5,6,7-hexahydro-1H-indene (4-MHI, C10H16) were the primary decomposition products of exo-THDCP. C10 hydrocarbons were determined to be the major products. The amount of C5−C7 hydrocarbons, such as cyclopentene, benzene, and toluene, were relatively small. We performed the molecular modeling (MM) on some of the compounds, including 1-CPCP and 4-MHI produced from exo-THDCP to evaluate the activation energy and molecular structure of the intermediates. The experimental and MM results showed that 1-CPCP and 4-MHI were independently formed from exo-THDCP. The experimental results closely corresponded with the MM result; the products that were only minimally produced after the reaction had qualitatively higher activation energies than the other products. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100065m
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8319–8324[article] Thermal stability and isomerization mechanism of exo-tetrahydrodicyclopentadiene : experimental study and molecular modeling [texte imprimé] / Sun Hee Park, Auteur ; Cheong Hoon Kwon, Auteur ; Joongyeon Kim, Auteur . - 2010 . - pp. 8319–8324.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8319–8324
Mots-clés : Thermal stability Résumé : Thermal stability and the primary initiation mechanism of exo-tetrahydrodicyclopentadiene (exo-THDCP, C10H16) were investigated in a batch-type reactor. The catalytic role of the stainless steel inside the reactor was eliminated by inserting a quartz flask. exo-THDCP decomposed at temperatures over 623 K and 1-cyclopentylcyclopentene (1-CPCP, C10H16) and 4-methyl-2,3,4,5,6,7-hexahydro-1H-indene (4-MHI, C10H16) were the primary decomposition products of exo-THDCP. C10 hydrocarbons were determined to be the major products. The amount of C5−C7 hydrocarbons, such as cyclopentene, benzene, and toluene, were relatively small. We performed the molecular modeling (MM) on some of the compounds, including 1-CPCP and 4-MHI produced from exo-THDCP to evaluate the activation energy and molecular structure of the intermediates. The experimental and MM results showed that 1-CPCP and 4-MHI were independently formed from exo-THDCP. The experimental results closely corresponded with the MM result; the products that were only minimally produced after the reaction had qualitatively higher activation energies than the other products. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100065m Exemplaires
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Titre : Cross-linking cotton cellulose by the combination of maleic acid and sodium hypophosphite. 1. : fabric wrinkle resistance Type de document : texte imprimé Auteurs : Charles Q. Yang, Auteur ; Dongzhong Chen, Auteur ; Jinping Guan, Auteur Année de publication : 2010 Article en page(s) : pp. 8325–8332 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hypophosphite Acid Résumé : Durable press finishing agents used to produce wrinkle-resistant cotton garments are cross-linking agents for cotton cellulose. Polycarboxylic acids have been the promising durable press finishing agents to replace the formaldehyde-based reagents when sodium hypophosphite (NaH2PO2) was used as the catalyst. In our previous research, we found that a polycarboxylic acid esterifies cotton cellulose by first forming a five-membered cyclic anhydride as a reactive intermediate. Maleic acid (MA) is a bifunctional carboxylic acid, therefore is not able to form the second cyclic anhydride intermediate once it forms the first ester linkage with cotton. However, we discovered that MA imparted wrinkle resistance to cotton fabrics when NaH2PO2 was present, thus indicating that MA was able to cross-link cotton. Sodium hypophosphite functions as the catalyst for the esterification of cellulose by MA, and the esterification takes place at relatively low temperatures (≥130 °C). Esterification of MA forms single esterlinkage with cellulose and does not cross-link cotton cellulose. As the temperature increases ≥160 °C, NaH2PO2 starts to be bound to cotton. The data suggested that H−P−H of hypophosphite likely reacts with the >C═C ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007294
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8325–8332[article] Cross-linking cotton cellulose by the combination of maleic acid and sodium hypophosphite. 1. : fabric wrinkle resistance [texte imprimé] / Charles Q. Yang, Auteur ; Dongzhong Chen, Auteur ; Jinping Guan, Auteur . - 2010 . - pp. 8325–8332.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8325–8332
Mots-clés : Hypophosphite Acid Résumé : Durable press finishing agents used to produce wrinkle-resistant cotton garments are cross-linking agents for cotton cellulose. Polycarboxylic acids have been the promising durable press finishing agents to replace the formaldehyde-based reagents when sodium hypophosphite (NaH2PO2) was used as the catalyst. In our previous research, we found that a polycarboxylic acid esterifies cotton cellulose by first forming a five-membered cyclic anhydride as a reactive intermediate. Maleic acid (MA) is a bifunctional carboxylic acid, therefore is not able to form the second cyclic anhydride intermediate once it forms the first ester linkage with cotton. However, we discovered that MA imparted wrinkle resistance to cotton fabrics when NaH2PO2 was present, thus indicating that MA was able to cross-link cotton. Sodium hypophosphite functions as the catalyst for the esterification of cellulose by MA, and the esterification takes place at relatively low temperatures (≥130 °C). Esterification of MA forms single esterlinkage with cellulose and does not cross-link cotton cellulose. As the temperature increases ≥160 °C, NaH2PO2 starts to be bound to cotton. The data suggested that H−P−H of hypophosphite likely reacts with the >C═C ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007294 Exemplaires
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Titre : Monitoring cellulase protein adsorption and recovery using SDS-PAGE Type de document : texte imprimé Auteurs : Gang Hu, Auteur ; John A. Heitmann, Auteur ; Orlando J. Rojas, Auteur Année de publication : 2010 Article en page(s) : pp. 8333–8338 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Microcrystalline celluloses Résumé : Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was employed to study the sorption behaviors of cellulases on microcrystalline celluloses and hardwood pulp. The adsorption and recovery of cellulases from Aspergillus niger and Trichoderma reesei were investigated at 25 °C. Cellulase recovery was conducted by rinsing adsorbed enzymes with sodium acetate buffer, Milli-Q water, and sodium hydroxide solution. The initial, equilibrium, and recovered enzymes were analyzed using SDS-PAGE gels. Gels were scanned and analyzed using ImagePro software. The molecular weights of cellulase proteins were determined using a protein marker having seven known proteins. The cellulase system from Trichoderma reesei had a higher adsorption on all substrates studied than the cellulase system from Aspergillius niger, and higher pH favored desorption from the substrates studied. Experimental results also demonstrated that adsorption and desorption amounts determined by SDS-PAGE were proportional to protein concentrations in their crude mixtures. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100731b
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8333–8338[article] Monitoring cellulase protein adsorption and recovery using SDS-PAGE [texte imprimé] / Gang Hu, Auteur ; John A. Heitmann, Auteur ; Orlando J. Rojas, Auteur . - 2010 . - pp. 8333–8338.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8333–8338
Mots-clés : Microcrystalline celluloses Résumé : Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was employed to study the sorption behaviors of cellulases on microcrystalline celluloses and hardwood pulp. The adsorption and recovery of cellulases from Aspergillus niger and Trichoderma reesei were investigated at 25 °C. Cellulase recovery was conducted by rinsing adsorbed enzymes with sodium acetate buffer, Milli-Q water, and sodium hydroxide solution. The initial, equilibrium, and recovered enzymes were analyzed using SDS-PAGE gels. Gels were scanned and analyzed using ImagePro software. The molecular weights of cellulase proteins were determined using a protein marker having seven known proteins. The cellulase system from Trichoderma reesei had a higher adsorption on all substrates studied than the cellulase system from Aspergillius niger, and higher pH favored desorption from the substrates studied. Experimental results also demonstrated that adsorption and desorption amounts determined by SDS-PAGE were proportional to protein concentrations in their crude mixtures. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100731b Exemplaires
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Titre : Solar light active photodegradation of phenol over a FexTi1−xO2−yNy nanophotocatalyst Type de document : texte imprimé Auteurs : Brundabana Naik, Auteur ; K. M. Parida, Auteur Année de publication : 2010 Article en page(s) : pp. 8339–8346 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanophotocatalyst Résumé : This article details the preparation, characterization, and catalytic activity evaluation of an efficient mesoporous FexTi1−xO2−yNy nanophotocatalyst (FeNT) for the degradation of phenol under direct solar light illumination. For fabrication of the FeNT, Fe doped TiO2 (FeT) was first prepared by a nonhydrolytic sol−gel route and N doping was subsequently performed by heating the resultant materials under a flow of NH3. The samples were analyzed by XRD, SEM, UV-vis DRS, FTIR, PL, and XPS to investigate the structural, electronic and optical features. FeNT samples exhibit about 1.5 fold higher direct solar light induced photocatalytic activity than the FeT catalyst and N doped TiO2 (NT). A noticeable red shift of the absorption edge and ca. 1.2 eV band gap narrowing is confirmed by UV-vis DRS. XPS has been applied to characterize the element oxidation state and near surface composition of catalysts. The presence of Fe ion facilitates the surface charge transfer process. Overall, the synergistic effect of iron and nitrogen greatly enhances the photocatalytic activity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100889m
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8339–8346[article] Solar light active photodegradation of phenol over a FexTi1−xO2−yNy nanophotocatalyst [texte imprimé] / Brundabana Naik, Auteur ; K. M. Parida, Auteur . - 2010 . - pp. 8339–8346.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8339–8346
Mots-clés : Nanophotocatalyst Résumé : This article details the preparation, characterization, and catalytic activity evaluation of an efficient mesoporous FexTi1−xO2−yNy nanophotocatalyst (FeNT) for the degradation of phenol under direct solar light illumination. For fabrication of the FeNT, Fe doped TiO2 (FeT) was first prepared by a nonhydrolytic sol−gel route and N doping was subsequently performed by heating the resultant materials under a flow of NH3. The samples were analyzed by XRD, SEM, UV-vis DRS, FTIR, PL, and XPS to investigate the structural, electronic and optical features. FeNT samples exhibit about 1.5 fold higher direct solar light induced photocatalytic activity than the FeT catalyst and N doped TiO2 (NT). A noticeable red shift of the absorption edge and ca. 1.2 eV band gap narrowing is confirmed by UV-vis DRS. XPS has been applied to characterize the element oxidation state and near surface composition of catalysts. The presence of Fe ion facilitates the surface charge transfer process. Overall, the synergistic effect of iron and nitrogen greatly enhances the photocatalytic activity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100889m Exemplaires
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Titre : Intermolecular interactions between surfactants and cationic dyes and effect on antimicrobial properties Type de document : texte imprimé Auteurs : Nastaran Hashemi, Auteur ; Gang Sun, Auteur Année de publication : 2010 Article en page(s) : pp. 8347–8352 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Cationic molecules Résumé : Cationic molecules can interact with anionic and other cationic species in solutions. Electrostatic and hydrophobic interactions between two series of cationic antimicrobial dyes and several surfactants were studied using a UV−vis spectrophotometer. The dye containing more cationic charges with a short alkyl chain showed stronger binding power with surfactants than the one with less positive charge, while the ones with longer chains exhibited lower binding energy. These dyes could form complex structures with anionic surfactant species in solutions at very low concentrations of the surfactant (far below critical-micelle-forming concentrations of the surfactants), which was revealed from the changes in absorbance and wavelength of the maximum absorbance (λmax) of photospectrometry. However, when the concentrations of surfactants were above their critical micelle concentrations, the dyes could redissolve and dissociate into molecular or ionic forms. Such results were confirmed by conductivity and antimicrobial functions of the solutions. These findings are useful in understanding the impact of anionic surfactants on cationic antimicrobial agents. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101001d
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8347–8352[article] Intermolecular interactions between surfactants and cationic dyes and effect on antimicrobial properties [texte imprimé] / Nastaran Hashemi, Auteur ; Gang Sun, Auteur . - 2010 . - pp. 8347–8352.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8347–8352
Mots-clés : Cationic molecules Résumé : Cationic molecules can interact with anionic and other cationic species in solutions. Electrostatic and hydrophobic interactions between two series of cationic antimicrobial dyes and several surfactants were studied using a UV−vis spectrophotometer. The dye containing more cationic charges with a short alkyl chain showed stronger binding power with surfactants than the one with less positive charge, while the ones with longer chains exhibited lower binding energy. These dyes could form complex structures with anionic surfactant species in solutions at very low concentrations of the surfactant (far below critical-micelle-forming concentrations of the surfactants), which was revealed from the changes in absorbance and wavelength of the maximum absorbance (λmax) of photospectrometry. However, when the concentrations of surfactants were above their critical micelle concentrations, the dyes could redissolve and dissociate into molecular or ionic forms. Such results were confirmed by conductivity and antimicrobial functions of the solutions. These findings are useful in understanding the impact of anionic surfactants on cationic antimicrobial agents. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101001d Exemplaires
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Titre : Electrochemical advanced oxidation of carbamazepine on boron-doped diamond anodes. influence of operating variables Type de document : texte imprimé Auteurs : Joaquin R. Dominguez, Auteur ; T. Gonzalez, Auteur ; P. Palo, Auteur Année de publication : 2010 Article en page(s) : pp. 8353–8359 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oxidation processes Electrochemical Résumé : A wide variety of drugs have been found in wastewater treatment effluents, rivers, and lakes, including analgesics, antibiotics, and antiepileptics. Electrochemical advanced oxidation processes are promising technologies to treat low contents of toxic and biorefractory pollutants in water. Anodic oxidation of carbamazepine, the most frequently detected drug in water bodies, was carried out using boron-doped diamond (BDD) anodes at galvanostatic mode. To optimize the process and study the interaction between the four modified variables (pH, current, concentration of supporting electrolyte Na2SO4, and solution flow rate) a design-of-experiments procedure has been carried out. The influence of these four variables has been evaluated. The influence of current was the greatest in the studied variables, the second one was the salt concentration, and the third one was the flow rate. ANOVA test reported significant for 5 of the 14 involved variables and the response surface methodology technique used to optimize carbamazepine degradation. An optimum carbamazepine degradation of 100% was found at pH 9, flow rate equal to 1.25 cm3 min−1, and current density equal to 190 mA cm−2 using a supporting electrolyte concentration equal to 0.48 mol L−1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101023u
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8353–8359[article] Electrochemical advanced oxidation of carbamazepine on boron-doped diamond anodes. influence of operating variables [texte imprimé] / Joaquin R. Dominguez, Auteur ; T. Gonzalez, Auteur ; P. Palo, Auteur . - 2010 . - pp. 8353–8359.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8353–8359
Mots-clés : Oxidation processes Electrochemical Résumé : A wide variety of drugs have been found in wastewater treatment effluents, rivers, and lakes, including analgesics, antibiotics, and antiepileptics. Electrochemical advanced oxidation processes are promising technologies to treat low contents of toxic and biorefractory pollutants in water. Anodic oxidation of carbamazepine, the most frequently detected drug in water bodies, was carried out using boron-doped diamond (BDD) anodes at galvanostatic mode. To optimize the process and study the interaction between the four modified variables (pH, current, concentration of supporting electrolyte Na2SO4, and solution flow rate) a design-of-experiments procedure has been carried out. The influence of these four variables has been evaluated. The influence of current was the greatest in the studied variables, the second one was the salt concentration, and the third one was the flow rate. ANOVA test reported significant for 5 of the 14 involved variables and the response surface methodology technique used to optimize carbamazepine degradation. An optimum carbamazepine degradation of 100% was found at pH 9, flow rate equal to 1.25 cm3 min−1, and current density equal to 190 mA cm−2 using a supporting electrolyte concentration equal to 0.48 mol L−1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101023u Exemplaires
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Titre : Approach for catalyst-product separation using recyclable liquid phase catalysis Type de document : texte imprimé Auteurs : Anil G. Panda, Auteur ; Yogesh P. Patil, Auteur ; Pawan J. Tambade, Auteur Année de publication : 2010 Article en page(s) : pp. 8360–8364 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Résumé : A novel recyclable liquid phase catalyst system consisting of polyether metal diphosphinite complex anchored in polyethylene glycol was developed. The concept involves the use of liquid phase catalyst that is soluble in organic solvents like toluene and was tested for a variety of reactions like hydroformylation, hydrogenation, carbon dioxide fixation, and C−C coupling reactions in a homogeneous manner. The catalyst, in liquid form, can be quantitatively separated from the reactants/products with the help of addition of antisolvent and thus can be easily recycled. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101244m
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8360–8364[article] Approach for catalyst-product separation using recyclable liquid phase catalysis [texte imprimé] / Anil G. Panda, Auteur ; Yogesh P. Patil, Auteur ; Pawan J. Tambade, Auteur . - 2010 . - pp. 8360–8364.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8360–8364
Mots-clés : Catalyst Résumé : A novel recyclable liquid phase catalyst system consisting of polyether metal diphosphinite complex anchored in polyethylene glycol was developed. The concept involves the use of liquid phase catalyst that is soluble in organic solvents like toluene and was tested for a variety of reactions like hydroformylation, hydrogenation, carbon dioxide fixation, and C−C coupling reactions in a homogeneous manner. The catalyst, in liquid form, can be quantitatively separated from the reactants/products with the help of addition of antisolvent and thus can be easily recycled. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101244m Exemplaires
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Titre : Speed of sound and excess isentropic compressibility of 1,3-dioxolane or 1,4-dioxane + butan-1-ol or + butan-2-ol binary mixtures at 308.15 K and atmospheric pressure Type de document : texte imprimé Auteurs : Satish Kumar, Auteur ; V. K. Sharma, Auteur ; Il Moon, Auteur Année de publication : 2010 Article en page(s) : pp. 8365-8368 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Atmospheric pressure Binary mixture Compressibility Résumé : Speed of sound (u12) of 1,3-dioxolane or 1,4-dioxane (1) + butan-1-ol or + butan-2-ol (2) binary mixtures were measured over entire composition range at 308.15 K and atmospheric pressure. The experimental data have been used to evaluate isentropic and excess isentropic compressibilities (κEs)12. Two methods, Redlich-Kister and Graph theory, were used to compute and correlate (κEs)12 values. Hence, (κEs)12 values were fitted to Redlich-Kister polynomial equation to derive binary coefficients and the standard errors between experimental and calculated quantities. (κEs)12 values were also analyzed by Graph theory, which involves the topology of the components of the mixture, to extract information about the state of components in pure and mixture states. It has been observed that (κEs)12 values analyzed by Graph theory compare well with their corresponding experimental values. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213969
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8365-8368[article] Speed of sound and excess isentropic compressibility of 1,3-dioxolane or 1,4-dioxane + butan-1-ol or + butan-2-ol binary mixtures at 308.15 K and atmospheric pressure [texte imprimé] / Satish Kumar, Auteur ; V. K. Sharma, Auteur ; Il Moon, Auteur . - 2010 . - pp. 8365-8368.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8365-8368
Mots-clés : Atmospheric pressure Binary mixture Compressibility Résumé : Speed of sound (u12) of 1,3-dioxolane or 1,4-dioxane (1) + butan-1-ol or + butan-2-ol (2) binary mixtures were measured over entire composition range at 308.15 K and atmospheric pressure. The experimental data have been used to evaluate isentropic and excess isentropic compressibilities (κEs)12. Two methods, Redlich-Kister and Graph theory, were used to compute and correlate (κEs)12 values. Hence, (κEs)12 values were fitted to Redlich-Kister polynomial equation to derive binary coefficients and the standard errors between experimental and calculated quantities. (κEs)12 values were also analyzed by Graph theory, which involves the topology of the components of the mixture, to extract information about the state of components in pure and mixture states. It has been observed that (κEs)12 values analyzed by Graph theory compare well with their corresponding experimental values. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213969 Exemplaires
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Titre : Dynamic modeling and optimization of a batch reactor for limonene epoxidation Type de document : texte imprimé Auteurs : Rolando Barrera Zapata, Auteur ; Aida Luz Villa, Auteur ; Consuelo Montes de Correa, Auteur Année de publication : 2010 Article en page(s) : pp. 8369–8378 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dynamic Optimization Résumé : A mathematical model for limonene epoxidation over PW-Amberlite in a batch reactor was developed and used for reactor simulation and optimization. The mathematical model was validated by comparison of predicted and experimentally determined limonene conversion under isothermal and nonisothermal conditions (23−50 °C) and for several limonene/oxidant molar ratios. By a sequential simulation and an optimization approach using genetic algorithms (GA), the temperature profiles minimizing the energy consumption and the variability of limonene conversion were obtained. Simulation of limonene epoxidation using the optimal temperature strategies showed that it is possible to achieve a limonene conversion of 80% in a shorter period of batch time when compared to typical isothermal conditions at 33 °C. The proposed model may also be used to scale up the catalytic system. As an illustrative example, an optimization formulation was proposed to estimate the minimum volume (18 L), the aspect ratio (height/diameter, H/D = 1.7), and the temperature profile that maximizes limonene conversion and minimizes energy consumption to obtain at least 1000 g of limonene epoxide. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100737y?journalCode=iecred
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8369–8378[article] Dynamic modeling and optimization of a batch reactor for limonene epoxidation [texte imprimé] / Rolando Barrera Zapata, Auteur ; Aida Luz Villa, Auteur ; Consuelo Montes de Correa, Auteur . - 2010 . - pp. 8369–8378.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8369–8378
Mots-clés : Dynamic Optimization Résumé : A mathematical model for limonene epoxidation over PW-Amberlite in a batch reactor was developed and used for reactor simulation and optimization. The mathematical model was validated by comparison of predicted and experimentally determined limonene conversion under isothermal and nonisothermal conditions (23−50 °C) and for several limonene/oxidant molar ratios. By a sequential simulation and an optimization approach using genetic algorithms (GA), the temperature profiles minimizing the energy consumption and the variability of limonene conversion were obtained. Simulation of limonene epoxidation using the optimal temperature strategies showed that it is possible to achieve a limonene conversion of 80% in a shorter period of batch time when compared to typical isothermal conditions at 33 °C. The proposed model may also be used to scale up the catalytic system. As an illustrative example, an optimization formulation was proposed to estimate the minimum volume (18 L), the aspect ratio (height/diameter, H/D = 1.7), and the temperature profile that maximizes limonene conversion and minimizes energy consumption to obtain at least 1000 g of limonene epoxide. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100737y?journalCode=iecred Exemplaires
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Titre : Kinetics study and characteristics of silica nanoparticles produced from biomass-based material Type de document : texte imprimé Auteurs : Tzong-Horng Liou, Auteur ; Shao-Jung Wu, Auteur Année de publication : 2010 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticles Biomass Kinetics Résumé : Rice husk, a form of biomass material, is a potential source of renewable energy. Recovering silica from rice husk is an important element in manufacturing high value-added products and ensures efficient utilization of a bioresource. This paper describes the kinetics and characteristics of silica prepared from rice husk in an oxidizing atmosphere. Experiments were conducted with rice husk powder under nonisothermal conditions with various gaseous flow rates, sample loadings, reactant grain sizes, oxygen concentrations, and heating rates. Samples were characterized by ICP-MS, XRD, FTIR, HT-DSC, FE-SEM, TEM, and N2-adsorption analyzer. Experimental results show that the silica yield can be increased by decreasing the grain size of raw husk. Acid-pretreatment of rice husk increases the purity, uniformity, surface area, and porosity of the final silica products. The average size of the silica particles was approximately 60 nm. Two distinct reaction stages were observed for total thermal degradation of the rice husk. This study determines the kinetic parameters of rice husk’s combustion reaction, including the activation energy, pre-exponential factor, and reaction order, using thermo-analytical techniques. This study also proposed a mechanism to illustrate the thermal decomposition of the rice husk, which agrees well with the experimental results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100050t
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010)[article] Kinetics study and characteristics of silica nanoparticles produced from biomass-based material [texte imprimé] / Tzong-Horng Liou, Auteur ; Shao-Jung Wu, Auteur . - 2010.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010)
Mots-clés : Nanoparticles Biomass Kinetics Résumé : Rice husk, a form of biomass material, is a potential source of renewable energy. Recovering silica from rice husk is an important element in manufacturing high value-added products and ensures efficient utilization of a bioresource. This paper describes the kinetics and characteristics of silica prepared from rice husk in an oxidizing atmosphere. Experiments were conducted with rice husk powder under nonisothermal conditions with various gaseous flow rates, sample loadings, reactant grain sizes, oxygen concentrations, and heating rates. Samples were characterized by ICP-MS, XRD, FTIR, HT-DSC, FE-SEM, TEM, and N2-adsorption analyzer. Experimental results show that the silica yield can be increased by decreasing the grain size of raw husk. Acid-pretreatment of rice husk increases the purity, uniformity, surface area, and porosity of the final silica products. The average size of the silica particles was approximately 60 nm. Two distinct reaction stages were observed for total thermal degradation of the rice husk. This study determines the kinetic parameters of rice husk’s combustion reaction, including the activation energy, pre-exponential factor, and reaction order, using thermo-analytical techniques. This study also proposed a mechanism to illustrate the thermal decomposition of the rice husk, which agrees well with the experimental results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100050t Exemplaires
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Titre : Copper-promoted ZnO/SiO2 regenerable sorbents for the room temperature removal of H2S from reformate gas streams Type de document : texte imprimé Auteurs : Priyanka Dhage, Auteur ; Alexander Samokhvalov, Auteur ; Divya Repala, Auteur Année de publication : 2010 Article en page(s) : pp. 8388–8396 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Reformate Gas Résumé : The Cu−ZnO/SiO2 sorbent for ultradeep adsorptive removal of H2S from the reformate streams at room temperature was prepared and tested, and characterization of the active sites was performed. The Cu dopant significantly enhances desulfurization capacity of ZnO/SiO2 sorbent at room temperature (up to 92% utilization of ZnO), and the sorbent maintains a high sulfur uptake capacity upon multiple cycles (up to 10) of regeneration by a simple thermal oxidation in air. The “as-prepared” (“calcined”) sorbent contains Cu in the Cu2+ form, O, Si, and Zn as ZnO, while the “spent” (“sulfided”) sorbent contains Cu, O, Si, S, and Zn as the ZnS form, as found by XPS. XRD suggests that both zinc and copper compounds of the Cu−ZnO/SiO2 sorbent are nanodispersed. ESR spectroscopy found that the “calcined” and “sulfided” Cu−ZnO/SiO2 sorbents contain Cu2+ in the single dispersion and coordination state. During H2S adsorption, partial reduction of Cu2+ to Cu+ occurs: the higher Cu concentration in the sorbent, the lower the reduction yield of Cu2+ to Cu+, thus correlating with sulfur uptake capacity. The “deactivated” sorbent (10−11 adsorption/regeneration cycles) is enriched with a different chemical form of Cu2+, compared to the “as-prepared” sorbent. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100209a
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8388–8396[article] Copper-promoted ZnO/SiO2 regenerable sorbents for the room temperature removal of H2S from reformate gas streams [texte imprimé] / Priyanka Dhage, Auteur ; Alexander Samokhvalov, Auteur ; Divya Repala, Auteur . - 2010 . - pp. 8388–8396.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8388–8396
Mots-clés : Reformate Gas Résumé : The Cu−ZnO/SiO2 sorbent for ultradeep adsorptive removal of H2S from the reformate streams at room temperature was prepared and tested, and characterization of the active sites was performed. The Cu dopant significantly enhances desulfurization capacity of ZnO/SiO2 sorbent at room temperature (up to 92% utilization of ZnO), and the sorbent maintains a high sulfur uptake capacity upon multiple cycles (up to 10) of regeneration by a simple thermal oxidation in air. The “as-prepared” (“calcined”) sorbent contains Cu in the Cu2+ form, O, Si, and Zn as ZnO, while the “spent” (“sulfided”) sorbent contains Cu, O, Si, S, and Zn as the ZnS form, as found by XPS. XRD suggests that both zinc and copper compounds of the Cu−ZnO/SiO2 sorbent are nanodispersed. ESR spectroscopy found that the “calcined” and “sulfided” Cu−ZnO/SiO2 sorbents contain Cu2+ in the single dispersion and coordination state. During H2S adsorption, partial reduction of Cu2+ to Cu+ occurs: the higher Cu concentration in the sorbent, the lower the reduction yield of Cu2+ to Cu+, thus correlating with sulfur uptake capacity. The “deactivated” sorbent (10−11 adsorption/regeneration cycles) is enriched with a different chemical form of Cu2+, compared to the “as-prepared” sorbent. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100209a Exemplaires
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Titre : Comparative Study in Liquid-Phase Heterogeneous Photocatalysis : Model for Photoreactor Scale-Up Type de document : texte imprimé Auteurs : Dong Li, Auteur ; Kui Xiong, Auteur ; Wei Li, Auteur Année de publication : 2010 Article en page(s) : pp. 8397–8405 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Photoreactors Photocatalysis Résumé : A scale-up model for photoreactors based on a comparative study of the photocatalytic efficiency of suspended and immobilized systems was developed. The model is independent of reactor size and configurations, and it assumes that photocatalytic efficiency is the same when normalized per unit of illuminated catalyst area in both systems. In all cases, phenol/TiO2 (Degussa P25) was selected as the photodegradation system. First, a kinetic model was built in an immobilized system based on the corresponding experimental data, and then predicted rates of phenol degradation in the suspended system were calculated using the above kinetic model combined with a simplified radiation model, which was expressed as an apparent form of the Lambert law. Second, to obtain experimental rates, experiments conducted in the suspended system were carried out under the same conditions used in the immobilized system. Ratios between experimental rates and predicted rates were obtained, revealing the differences in efficiency between the suspended and immobilized systems. The typical value of the ratio was 2.5−9.2, suggesting that the efficiency of the suspended system was 2.5−9.2 times higher than that of the immobilized system. The ratio decreased with increasing concentrations of both phenol and catalyst. When the catalyst concentration and initial concentration of phenol were set, the ratio became constant within the range of the light intensity of 1.71−3.60 mW cm−2. Finally, for photoreactor scale-up, the proposed model was validated in a larger photoreactor operated in the suspended system, and good agreements were obtained with errors less than 5%. This methodology provides an alternative to the scale-up of photoreactors, which allows for easier engineering applications. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100277g
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8397–8405[article] Comparative Study in Liquid-Phase Heterogeneous Photocatalysis : Model for Photoreactor Scale-Up [texte imprimé] / Dong Li, Auteur ; Kui Xiong, Auteur ; Wei Li, Auteur . - 2010 . - pp. 8397–8405.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8397–8405
Mots-clés : Photoreactors Photocatalysis Résumé : A scale-up model for photoreactors based on a comparative study of the photocatalytic efficiency of suspended and immobilized systems was developed. The model is independent of reactor size and configurations, and it assumes that photocatalytic efficiency is the same when normalized per unit of illuminated catalyst area in both systems. In all cases, phenol/TiO2 (Degussa P25) was selected as the photodegradation system. First, a kinetic model was built in an immobilized system based on the corresponding experimental data, and then predicted rates of phenol degradation in the suspended system were calculated using the above kinetic model combined with a simplified radiation model, which was expressed as an apparent form of the Lambert law. Second, to obtain experimental rates, experiments conducted in the suspended system were carried out under the same conditions used in the immobilized system. Ratios between experimental rates and predicted rates were obtained, revealing the differences in efficiency between the suspended and immobilized systems. The typical value of the ratio was 2.5−9.2, suggesting that the efficiency of the suspended system was 2.5−9.2 times higher than that of the immobilized system. The ratio decreased with increasing concentrations of both phenol and catalyst. When the catalyst concentration and initial concentration of phenol were set, the ratio became constant within the range of the light intensity of 1.71−3.60 mW cm−2. Finally, for photoreactor scale-up, the proposed model was validated in a larger photoreactor operated in the suspended system, and good agreements were obtained with errors less than 5%. This methodology provides an alternative to the scale-up of photoreactors, which allows for easier engineering applications. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100277g Exemplaires
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Titre : Effect of methanol on the gas-phase reaction of trifluoromethane with methane Type de document : texte imprimé Auteurs : Wenfeng Han, Auteur ; Eric M. Kennedy, Auteur ; John C. Mackie, Auteur Année de publication : 2010 Article en page(s) : pp. 8406–8414 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gaseous phase reaction Résumé : The reaction of CHF3 with CH4 in the presence of small amounts of CH3OH (5% of CHF3 concentration) was investigated in a tubular alumina reactor at temperatures between 900 K and 1150 K. The presence of CH3OH has a significant influence on both the conversion and selectivity of the reaction. Increasing the CH3OH concentration enhances the conversion of CHF3 by a factor of 1−4 times at temperatures between 873 K and 1123 K, although the rate of formation of the major products (CH2═CF2) does not increase. A reaction scheme, based on NIST HFC and GRI-Mech mechanisms, is developed to model the reactions. Satisfactory agreement between experimental results and predictions is achieved for the conversion of reactants and formation of products. Based on experimental measurements and modeling results, a detailed reaction mechanism is proposed, and insight into how CH3OH influences the reaction of CHF3 with CH4 is presented. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213974
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8406–8414[article] Effect of methanol on the gas-phase reaction of trifluoromethane with methane [texte imprimé] / Wenfeng Han, Auteur ; Eric M. Kennedy, Auteur ; John C. Mackie, Auteur . - 2010 . - pp. 8406–8414.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8406–8414
Mots-clés : Gaseous phase reaction Résumé : The reaction of CHF3 with CH4 in the presence of small amounts of CH3OH (5% of CHF3 concentration) was investigated in a tubular alumina reactor at temperatures between 900 K and 1150 K. The presence of CH3OH has a significant influence on both the conversion and selectivity of the reaction. Increasing the CH3OH concentration enhances the conversion of CHF3 by a factor of 1−4 times at temperatures between 873 K and 1123 K, although the rate of formation of the major products (CH2═CF2) does not increase. A reaction scheme, based on NIST HFC and GRI-Mech mechanisms, is developed to model the reactions. Satisfactory agreement between experimental results and predictions is achieved for the conversion of reactants and formation of products. Based on experimental measurements and modeling results, a detailed reaction mechanism is proposed, and insight into how CH3OH influences the reaction of CHF3 with CH4 is presented. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213974 Exemplaires
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Titre : Kinetic modeling of n-butane cracking on HZSM-5 zeolite catalyst Type de document : texte imprimé Auteurs : Diana Mier, Auteur ; Andrés T. Aguayo, Auteur ; Monica Gamero, Auteur Année de publication : 2010 Article en page(s) : pp. 8415–8423 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Modeling Catalyst Zeolite Cracking Kinetic model Résumé : A kinetic model of lumps has been established for n-butane cracking over HZSM-5 zeolitc catalyst (SiO2/ Al2O3 = 30) in the 400-550 °C range, based on the results obtained in a fixed bed reactor (space time, up to 2.4 (g of catalyst) h (mol CH2)-1; He/n-butane molar ratio in the feed, up to 6/l; time on stream, 5 h). The model allows quantifying the distribution of the lumps of products (C2-C4 olefins, C2-C4 paraffins, methane, and C5-C10 components) in a wide range of temperatures, partial pressures of hydrocarbons in the reaction medium, and space times. The kinetic model steps for the transformation of n-butane into olefins and of olefins into paraffins and C5-C10 are second order with respect to the reactant, whereas the remaining steps are first order with respect to each reactant. When the target is the production of C2-C4 oletins, the yield is limited to 12%, at 550 °C. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213975
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8415–8423[article] Kinetic modeling of n-butane cracking on HZSM-5 zeolite catalyst [texte imprimé] / Diana Mier, Auteur ; Andrés T. Aguayo, Auteur ; Monica Gamero, Auteur . - 2010 . - pp. 8415–8423.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8415–8423
Mots-clés : Modeling Catalyst Zeolite Cracking Kinetic model Résumé : A kinetic model of lumps has been established for n-butane cracking over HZSM-5 zeolitc catalyst (SiO2/ Al2O3 = 30) in the 400-550 °C range, based on the results obtained in a fixed bed reactor (space time, up to 2.4 (g of catalyst) h (mol CH2)-1; He/n-butane molar ratio in the feed, up to 6/l; time on stream, 5 h). The model allows quantifying the distribution of the lumps of products (C2-C4 olefins, C2-C4 paraffins, methane, and C5-C10 components) in a wide range of temperatures, partial pressures of hydrocarbons in the reaction medium, and space times. The kinetic model steps for the transformation of n-butane into olefins and of olefins into paraffins and C5-C10 are second order with respect to the reactant, whereas the remaining steps are first order with respect to each reactant. When the target is the production of C2-C4 oletins, the yield is limited to 12%, at 550 °C. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213975 Exemplaires
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Titre : Long-time behavior of the catalytic partial oxidation of glycerol in an autothermal reactor Type de document : texte imprimé Auteurs : David C. Rennard, Auteur ; Jacob S. Kruger, Auteur ; Brian C. Michael, Auteur Année de publication : 2010 Article en page(s) : pp. 8424–8432 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Autothermal reactor Résumé : We performed a long-term study of the autothermal reforming of glycerol. Liquid glycerol and water were introduced into a quartz reactor at room temperature and mixed with air in a nebulizer. The aerosol reacted to form H2, H2O, CO, and CO2 over a bed of spherical Rh−Ce/CeO2/Al2O3 particles, with minor production of C2+ species. Catalyst deactivation was exhibited by a decrease in the production of H2 and CO2 and increases in CO and temperature over 450 h. The product changes suggest reduction in the water−gas shift reaction, which is typically promoted by Ce. SEM analysis indicated sintering of the catalyst due to high reaction temperatures, and EDS showed inorganic deposits on the walls of the quartz reactor and on the catalyst spheres. Etching of the quartz reactor shell was also observed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100405h
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8424–8432[article] Long-time behavior of the catalytic partial oxidation of glycerol in an autothermal reactor [texte imprimé] / David C. Rennard, Auteur ; Jacob S. Kruger, Auteur ; Brian C. Michael, Auteur . - 2010 . - pp. 8424–8432.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8424–8432
Mots-clés : Autothermal reactor Résumé : We performed a long-term study of the autothermal reforming of glycerol. Liquid glycerol and water were introduced into a quartz reactor at room temperature and mixed with air in a nebulizer. The aerosol reacted to form H2, H2O, CO, and CO2 over a bed of spherical Rh−Ce/CeO2/Al2O3 particles, with minor production of C2+ species. Catalyst deactivation was exhibited by a decrease in the production of H2 and CO2 and increases in CO and temperature over 450 h. The product changes suggest reduction in the water−gas shift reaction, which is typically promoted by Ce. SEM analysis indicated sintering of the catalyst due to high reaction temperatures, and EDS showed inorganic deposits on the walls of the quartz reactor and on the catalyst spheres. Etching of the quartz reactor shell was also observed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100405h Exemplaires
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Titre : Investigation of calcination and O2 plasma treatment effects on TiO2-supported palladium catalysts Type de document : texte imprimé Auteurs : Yanan Li, Auteur ; Ben W.-L. Jang, Auteur Année de publication : 2010 Article en page(s) : pp. 8433-8438 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Titanium oxide Plasma Calcining Résumé : This study focuses on investigating the effects of conventional calcination procedures and O2 plasma treatments on the metal precursor-support interaction (MPSI) of 1 wt % Pd/TiO2. MPSI is likely a strong precursor to the metal-support interaction of supported metal catalysts. The authors identify H2-DSC (H2-differential scanning calorimetry) as a sensitive and effective technique for measuring and differentiating the MPSIs of PdO and palladium nitrate with TiO2. At room temperature, the effect of O2 plasmas on MPSI is stronger than the effect of high-temperature calcination. In addition, O2 plasma treatments can increase the strength of the MPSIs of both supported PdO and palladium nitrate while minimizing the detrimental effects of high-temperature calcinations on the composition of supported metal precursors. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213977
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8433-8438[article] Investigation of calcination and O2 plasma treatment effects on TiO2-supported palladium catalysts [texte imprimé] / Yanan Li, Auteur ; Ben W.-L. Jang, Auteur . - 2010 . - pp. 8433-8438.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8433-8438
Mots-clés : Catalyst Titanium oxide Plasma Calcining Résumé : This study focuses on investigating the effects of conventional calcination procedures and O2 plasma treatments on the metal precursor-support interaction (MPSI) of 1 wt % Pd/TiO2. MPSI is likely a strong precursor to the metal-support interaction of supported metal catalysts. The authors identify H2-DSC (H2-differential scanning calorimetry) as a sensitive and effective technique for measuring and differentiating the MPSIs of PdO and palladium nitrate with TiO2. At room temperature, the effect of O2 plasmas on MPSI is stronger than the effect of high-temperature calcination. In addition, O2 plasma treatments can increase the strength of the MPSIs of both supported PdO and palladium nitrate while minimizing the detrimental effects of high-temperature calcinations on the composition of supported metal precursors. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213977 Exemplaires
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Titre : Synthesis of methyl isobutyl ketone over Pd/MgO/SiO2 Type de document : texte imprimé Auteurs : Jonathan J. Gamman, Auteur ; S. David Jackson, Auteur ; Fiona A. Wigzell, Auteur Année de publication : 2010 Article en page(s) : pp. 8439–8443 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalysts Gas phase Résumé : In this paper, we have examined the activity and selectivity of catalysts for the one-step, gas phase production of methyl isobutyl ketone (MIBK) from acetone (propanone) over the temperature range 373−573 K. The catalysts used were an impregnated MgO/silica, a Pd-MgO/silica formed from coimpregnation of the nitrates, and a Pd supported on a 1% Mg doped silica, Pd/Mg-SiO2. Using MgO/silica, mesityl oxide (MO) was formed with 100% selectivity at 373 and 473 K. Addition of Pd gave 100% selectivity to MIBK at 373 K, albeit at low conversion. Pd-MgO/silica revealed a promotional effect of the MgO on the hydrogenation function of the Pd and a promotional effect of the Pd on the aldol condensation activity of the MgO. The Pd/Mg-SiO2 catalyst showed high selectivity but low conversion, as no promoting effect was observed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100770e
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8439–8443[article] Synthesis of methyl isobutyl ketone over Pd/MgO/SiO2 [texte imprimé] / Jonathan J. Gamman, Auteur ; S. David Jackson, Auteur ; Fiona A. Wigzell, Auteur . - 2010 . - pp. 8439–8443.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8439–8443
Mots-clés : Catalysts Gas phase Résumé : In this paper, we have examined the activity and selectivity of catalysts for the one-step, gas phase production of methyl isobutyl ketone (MIBK) from acetone (propanone) over the temperature range 373−573 K. The catalysts used were an impregnated MgO/silica, a Pd-MgO/silica formed from coimpregnation of the nitrates, and a Pd supported on a 1% Mg doped silica, Pd/Mg-SiO2. Using MgO/silica, mesityl oxide (MO) was formed with 100% selectivity at 373 and 473 K. Addition of Pd gave 100% selectivity to MIBK at 373 K, albeit at low conversion. Pd-MgO/silica revealed a promotional effect of the MgO on the hydrogenation function of the Pd and a promotional effect of the Pd on the aldol condensation activity of the MgO. The Pd/Mg-SiO2 catalyst showed high selectivity but low conversion, as no promoting effect was observed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100770e Exemplaires
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Titre : Comparison of formic and sulfuric acids as a glucose decomposition catalyst Type de document : texte imprimé Auteurs : Laura Kupiainen, Auteur ; Juha Ahola, Auteur ; Juha Tanskanen, Auteur Année de publication : 2010 Article en page(s) : pp. 8444–8449 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Sulfuric acids Catalyst Résumé : Dilute sulfuric acid hydrolysis of cellulose is the oldest and a well-studied technology for converting biomass to ethanol. Despite continuous technology improvements, the process still gives only a moderate selectivity due to glucose decomposition in the cellulose hydrolysis conditions. According to the recent literature, carboxylic acids have been recognized as more selective acid hydrolysis catalysts than sulfuric acid in low hydrogen ion concentrations. In this paper, formic acid was compared to sulfuric acid as a glucose decomposition catalyst at values below pH 2.2 at 180−220 °C. It was found that glucose decomposition depends only on the hydrogen ion concentration in the prevailing reaction conditions and is independent of the hydrogen ion source. Earlier contradictory findings can be the consequence of ignoring the temperature function of the dissociation constants of the acids and setting hydrogen ion concentrations at room temperature. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008822
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8444–8449[article] Comparison of formic and sulfuric acids as a glucose decomposition catalyst [texte imprimé] / Laura Kupiainen, Auteur ; Juha Ahola, Auteur ; Juha Tanskanen, Auteur . - 2010 . - pp. 8444–8449.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8444–8449
Mots-clés : Sulfuric acids Catalyst Résumé : Dilute sulfuric acid hydrolysis of cellulose is the oldest and a well-studied technology for converting biomass to ethanol. Despite continuous technology improvements, the process still gives only a moderate selectivity due to glucose decomposition in the cellulose hydrolysis conditions. According to the recent literature, carboxylic acids have been recognized as more selective acid hydrolysis catalysts than sulfuric acid in low hydrogen ion concentrations. In this paper, formic acid was compared to sulfuric acid as a glucose decomposition catalyst at values below pH 2.2 at 180−220 °C. It was found that glucose decomposition depends only on the hydrogen ion concentration in the prevailing reaction conditions and is independent of the hydrogen ion source. Earlier contradictory findings can be the consequence of ignoring the temperature function of the dissociation constants of the acids and setting hydrogen ion concentrations at room temperature. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008822 Exemplaires
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Titre : Research on reactive adsorption desulfurization over Ni/ZnO−SiO2−Al2O3 adsorbent in a fixed-fluidized bed reactor Type de document : texte imprimé Auteurs : Jingxin Fan, Auteur ; Gang Wang, Auteur ; Yu Sun, Auteur Année de publication : 2010 Article en page(s) : pp. 8450–8460 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Desulfurization Adsorption Résumé : Reactive adsorption desulfurization of FCC gasoline over a Ni/ZnO−SiO2−Al2O3 adsorbent was carried out in a fixed-fluidized bed reactor at low pressures in the presence of hydrogen. The results show that high temperature, high pressure, high molar ratios of hydrogen-to-oil, and low weight hourly space velocity are favorable to improve the desulfurization ability of adsorbent but not conducive to maintaining the octane number of FCC gasoline throughout the condition range examined. Under optimal operating conditions, ultralow sulfur gasoline can be produced, and the RON loss is only 1 unit. Furthermore, the effect of prereduction and adsorbent characterization data (SEM/EDX, N2 adsorption) reveal that reduction increases the interaction between Ni and S compounds and improves the pore structure of adsorbent, leading to a significant improvement in the desulfurization capability of adsorbent. Take 3-methylthiophene for example, after adsorbing on an active Ni atom via the S−Ni bond, the sulfur of 3-methylthiophene is removed by direct hydrogenolysis of the C−S bond, resulting in the formation of NiSx and 2-methyl-1,3-butadiene in hydrogen atmosphere. The latter is mainly hydrogenated to 2-methyl-2-butene and 2-methylbutane. ZnO acts as a sulfur-acceptor, which can regenerate the active Ni in situ in hydrogen atmosphere. The complete sulfidation of adsorbent particles takes place by ion diffusion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100923v
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8450–8460[article] Research on reactive adsorption desulfurization over Ni/ZnO−SiO2−Al2O3 adsorbent in a fixed-fluidized bed reactor [texte imprimé] / Jingxin Fan, Auteur ; Gang Wang, Auteur ; Yu Sun, Auteur . - 2010 . - pp. 8450–8460.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8450–8460
Mots-clés : Desulfurization Adsorption Résumé : Reactive adsorption desulfurization of FCC gasoline over a Ni/ZnO−SiO2−Al2O3 adsorbent was carried out in a fixed-fluidized bed reactor at low pressures in the presence of hydrogen. The results show that high temperature, high pressure, high molar ratios of hydrogen-to-oil, and low weight hourly space velocity are favorable to improve the desulfurization ability of adsorbent but not conducive to maintaining the octane number of FCC gasoline throughout the condition range examined. Under optimal operating conditions, ultralow sulfur gasoline can be produced, and the RON loss is only 1 unit. Furthermore, the effect of prereduction and adsorbent characterization data (SEM/EDX, N2 adsorption) reveal that reduction increases the interaction between Ni and S compounds and improves the pore structure of adsorbent, leading to a significant improvement in the desulfurization capability of adsorbent. Take 3-methylthiophene for example, after adsorbing on an active Ni atom via the S−Ni bond, the sulfur of 3-methylthiophene is removed by direct hydrogenolysis of the C−S bond, resulting in the formation of NiSx and 2-methyl-1,3-butadiene in hydrogen atmosphere. The latter is mainly hydrogenated to 2-methyl-2-butene and 2-methylbutane. ZnO acts as a sulfur-acceptor, which can regenerate the active Ni in situ in hydrogen atmosphere. The complete sulfidation of adsorbent particles takes place by ion diffusion. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100923v Exemplaires
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Titre : Microwave-assisted noncatalytic destruction of volatile organic compounds using ceramic-based microwave absorbing media Type de document : texte imprimé Auteurs : Sameer Pallavkar, Auteur ; Tae-Hoon Kim, Auteur ; Jerry Lin, Auteur Année de publication : 2010 Article en page(s) : pp. 8461–8469 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Chemical process industry Résumé : Volatile organic compound (VOC) emissions from various sources such as chemical process industry, manufacturing industry, and automobiles have been an environmental and health concern. With the emerging emphasis on using green technologies to minimize greenhouse gas emissions, the use of microwave energy to achieve VOC emissions control with its electric power coming from nongreenhouse-related energy sources, such as wind, geothermal, solar, or even nuclear energy, becomes an attractive option. In this study, an experimental investigation involving the use of microwave energy to accomplish high temperature destruction of p-xylene in a packed bed reactor was performed using a SiC (silicon carbide) foam as the microwave absorbing media with air or nitrogen being the carrier gas. The experimental facilities consisted of a gas cylinder, a mass flow controller, a p-xylene vaporizer, a packed bed reactor packed with a SiC foam, a microwave applicator, and a gas chromatograph/mass spectrometer (GC/MS) for gas analysis. The SiC was found to be an excellent microwave absorber, which efficiently converts the microwave energy into heat energy. It was observed that the SiC temperature rises rapidly upon microwave irradiation and reaches a steady state temperature of higher than 800 °C within 2−3 min depending on the experimental conditions. A semiempirical energy balance model was formulated to describe the dynamic temperature profiles of the SiC in the reactor, and the model was found to simulate the observed profiles reasonably well. The destruction and removal efficiencies (DREs) for p-xylene were observed to reach 100% for all the experiments conducted with air being the carrier gas; however, the DREs never reached 100% with nitrogen being the carrier gas and the major destruction byproducts were observed to be benzene, toluene, styrene, biphenyl, and the unreacted p-xylene. The study has demonstrated that the microwave technology can be effectively developed to control the emissions of low concentrations of VOCs, especially in air. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1009734
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8461–8469[article] Microwave-assisted noncatalytic destruction of volatile organic compounds using ceramic-based microwave absorbing media [texte imprimé] / Sameer Pallavkar, Auteur ; Tae-Hoon Kim, Auteur ; Jerry Lin, Auteur . - 2010 . - pp. 8461–8469.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8461–8469
Mots-clés : Chemical process industry Résumé : Volatile organic compound (VOC) emissions from various sources such as chemical process industry, manufacturing industry, and automobiles have been an environmental and health concern. With the emerging emphasis on using green technologies to minimize greenhouse gas emissions, the use of microwave energy to achieve VOC emissions control with its electric power coming from nongreenhouse-related energy sources, such as wind, geothermal, solar, or even nuclear energy, becomes an attractive option. In this study, an experimental investigation involving the use of microwave energy to accomplish high temperature destruction of p-xylene in a packed bed reactor was performed using a SiC (silicon carbide) foam as the microwave absorbing media with air or nitrogen being the carrier gas. The experimental facilities consisted of a gas cylinder, a mass flow controller, a p-xylene vaporizer, a packed bed reactor packed with a SiC foam, a microwave applicator, and a gas chromatograph/mass spectrometer (GC/MS) for gas analysis. The SiC was found to be an excellent microwave absorber, which efficiently converts the microwave energy into heat energy. It was observed that the SiC temperature rises rapidly upon microwave irradiation and reaches a steady state temperature of higher than 800 °C within 2−3 min depending on the experimental conditions. A semiempirical energy balance model was formulated to describe the dynamic temperature profiles of the SiC in the reactor, and the model was found to simulate the observed profiles reasonably well. The destruction and removal efficiencies (DREs) for p-xylene were observed to reach 100% for all the experiments conducted with air being the carrier gas; however, the DREs never reached 100% with nitrogen being the carrier gas and the major destruction byproducts were observed to be benzene, toluene, styrene, biphenyl, and the unreacted p-xylene. The study has demonstrated that the microwave technology can be effectively developed to control the emissions of low concentrations of VOCs, especially in air. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1009734 Exemplaires
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Titre : Chemical production of pectic oligosaccharides from orange peel wastes Type de document : texte imprimé Auteurs : Martina Martinez, Auteur ; Remedios Yáñez, Auteur ; Jose Luis Alonso, Auteur Année de publication : 2010 Article en page(s) : pp. 8470–8476 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oligosaccharides Résumé : Orange peel wastes (OPW) were extracted with water to remove soluble material, and the resulting solid phase (which was obtained at a yield of 48.8 kg/100 kg of OPW, oven-dry basis) was employed as a substrate for the manufacture of pectic oligosaccharides by nonisothermal processing with hot, compressed water (autohydrolysis or hydrothermal treatments). The effects of treatments on the composition of both liquors and spent solids were assessed in terms of the severity factor (Ro). Operating under selected conditions (maximum temperature of 160 °C, corresponding to Ro = 288 min), the oligosaccharide yield (including oligogalacturonides, arabinooligosaccharides, and galactooligosaccharides) accounted for 25.1 kg/100 kg of extracted OPW, whereas limited concentrations monosaccharides and nonsaccharide compounds were present in the reaction media. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101066m
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8470–8476[article] Chemical production of pectic oligosaccharides from orange peel wastes [texte imprimé] / Martina Martinez, Auteur ; Remedios Yáñez, Auteur ; Jose Luis Alonso, Auteur . - 2010 . - pp. 8470–8476.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8470–8476
Mots-clés : Oligosaccharides Résumé : Orange peel wastes (OPW) were extracted with water to remove soluble material, and the resulting solid phase (which was obtained at a yield of 48.8 kg/100 kg of OPW, oven-dry basis) was employed as a substrate for the manufacture of pectic oligosaccharides by nonisothermal processing with hot, compressed water (autohydrolysis or hydrothermal treatments). The effects of treatments on the composition of both liquors and spent solids were assessed in terms of the severity factor (Ro). Operating under selected conditions (maximum temperature of 160 °C, corresponding to Ro = 288 min), the oligosaccharide yield (including oligogalacturonides, arabinooligosaccharides, and galactooligosaccharides) accounted for 25.1 kg/100 kg of extracted OPW, whereas limited concentrations monosaccharides and nonsaccharide compounds were present in the reaction media. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101066m Exemplaires
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Titre : Comparative studies on morphological, electrochemical, and mechanical properties of S-polyvinyl chloride based heterogeneous cation-exchange membranes with different resin ratio loading Type de document : texte imprimé Auteurs : A. R. Khodabakhshi, Auteur ; S. S. Madaeni, Auteur ; Hosseini, S. M., Auteur Année de publication : 2010 Article en page(s) : pp. 8477–8487 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Mechanical properties Résumé : Heterogeneous types of ion exchange membranes were prepared from S-polyvinyl chloride (S-PVC) as binder and tetrahydrofuran as solvent. Cation exchange resin powder was used in casting solutions to make ion exchange membranes with cationic functional groups. The relationship between resin ratio loading and morphological, electrochemical, and mechanical properties of prepared membranes were studied and evaluated. Membrane potential measurements were performed in monovalent (NaCl) and bivalent (BaCl2) electrolyte solutions in order to observe the selectivity of these membranes for different types of counterions. The results reveal that an increment of resin ratio loading leads to an increase of ion exchange capacity, fixed ion concentration, ionic permeability, current efficiency, water content, hydrophilicity, transport number, conductivity, and specific surface area for prepared membranes. However, the electrical resistance, energy consumption, membrane oxidative stability, and mechanical properties were decreased. Moreover, prepared membranes show different properties for monovalent (Na+) ions and bivalent (Ba2+) ions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9014205
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8477–8487[article] Comparative studies on morphological, electrochemical, and mechanical properties of S-polyvinyl chloride based heterogeneous cation-exchange membranes with different resin ratio loading [texte imprimé] / A. R. Khodabakhshi, Auteur ; S. S. Madaeni, Auteur ; Hosseini, S. M., Auteur . - 2010 . - pp. 8477–8487.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8477–8487
Mots-clés : Mechanical properties Résumé : Heterogeneous types of ion exchange membranes were prepared from S-polyvinyl chloride (S-PVC) as binder and tetrahydrofuran as solvent. Cation exchange resin powder was used in casting solutions to make ion exchange membranes with cationic functional groups. The relationship between resin ratio loading and morphological, electrochemical, and mechanical properties of prepared membranes were studied and evaluated. Membrane potential measurements were performed in monovalent (NaCl) and bivalent (BaCl2) electrolyte solutions in order to observe the selectivity of these membranes for different types of counterions. The results reveal that an increment of resin ratio loading leads to an increase of ion exchange capacity, fixed ion concentration, ionic permeability, current efficiency, water content, hydrophilicity, transport number, conductivity, and specific surface area for prepared membranes. However, the electrical resistance, energy consumption, membrane oxidative stability, and mechanical properties were decreased. Moreover, prepared membranes show different properties for monovalent (Na+) ions and bivalent (Ba2+) ions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9014205 Exemplaires
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Titre : Rebar corrosion in mortars containing calcareous filler Type de document : texte imprimé Auteurs : O. R. Batic, Auteur ; J. D. Sota, Auteur ; J. L. Fernandez, Auteur Année de publication : 2010 Article en page(s) : pp. 8488–8494 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Corrosion Résumé : Ordinary portland cement can be replaced, partially, by mineral admixtures which modify the properties of concrete and influence rebar corrosion. The most common mineral admixtures are puzzolans, granulated blast furnace slag, calcareous filler, fly ash with high and low lime content, condensed silica fumes, and rice hush ash. There is an increasing tendency to incorporate carbonate additions to mortars. The beneficial effect of calcareous filler addition has been long discussed although not many studies have been made on the effect of this addition on rebar corrosion. In this research, rebar corrosion in mortar containing calcareous filler was studied employing two water/cement (w/c) ratios: 0.50 and 0.65, respectively. It was found that rebar corrosion became important as the w/c increased. The presence of calcium carbonate altered the structure of the passive layer on rebars. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100045t
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8488–8494[article] Rebar corrosion in mortars containing calcareous filler [texte imprimé] / O. R. Batic, Auteur ; J. D. Sota, Auteur ; J. L. Fernandez, Auteur . - 2010 . - pp. 8488–8494.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8488–8494
Mots-clés : Corrosion Résumé : Ordinary portland cement can be replaced, partially, by mineral admixtures which modify the properties of concrete and influence rebar corrosion. The most common mineral admixtures are puzzolans, granulated blast furnace slag, calcareous filler, fly ash with high and low lime content, condensed silica fumes, and rice hush ash. There is an increasing tendency to incorporate carbonate additions to mortars. The beneficial effect of calcareous filler addition has been long discussed although not many studies have been made on the effect of this addition on rebar corrosion. In this research, rebar corrosion in mortar containing calcareous filler was studied employing two water/cement (w/c) ratios: 0.50 and 0.65, respectively. It was found that rebar corrosion became important as the w/c increased. The presence of calcium carbonate altered the structure of the passive layer on rebars. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100045t Exemplaires
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Titre : Encapsulation of α-tocopheryl acetate into zeolite Y for textile application Type de document : texte imprimé Auteurs : Eduardo Perez, Auteur ; Luis Martín, Auteur ; Cesar Rubio, Auteur Année de publication : 2010 Article en page(s) : pp. 8495-8500 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Textile industry Zeolite Encapsulation Résumé : A useful encapsulation methodology has been developed to fabricate α-tocopheryl acctate-zeolite Y microcapsules. These new microcapsules have been applied to obtain special textile polyamide fibers. The presence of α-tocopheryl acetate in both microcapsules and special fibers has been qualitatively and quantitatively determined using various techniques such as thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), and high performance liquid chromatography (HPLC). Two different techniques to extract the α-tocopheryl acetate encapsulated in both microcapsules and special fibers have been compared: liquid-liquid extraction, that gives the best results under the studied conditions, and supercritical CO2 extraction, which is useful when there are mass trinsfer limitations as in the case of the special fibers. Mechanical properties of the fiber do not significantly change when they are fabricated with zeolite Y microcapsules. Finally, fabrics knitted with yams of α-tocopheryl acetate-zeolite Y microcapsules state a significant presence of the additive after 100 washing machine cycles (30 °C, neutral soap). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213985
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8495-8500[article] Encapsulation of α-tocopheryl acetate into zeolite Y for textile application [texte imprimé] / Eduardo Perez, Auteur ; Luis Martín, Auteur ; Cesar Rubio, Auteur . - 2010 . - pp. 8495-8500.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8495-8500
Mots-clés : Textile industry Zeolite Encapsulation Résumé : A useful encapsulation methodology has been developed to fabricate α-tocopheryl acctate-zeolite Y microcapsules. These new microcapsules have been applied to obtain special textile polyamide fibers. The presence of α-tocopheryl acetate in both microcapsules and special fibers has been qualitatively and quantitatively determined using various techniques such as thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), and high performance liquid chromatography (HPLC). Two different techniques to extract the α-tocopheryl acetate encapsulated in both microcapsules and special fibers have been compared: liquid-liquid extraction, that gives the best results under the studied conditions, and supercritical CO2 extraction, which is useful when there are mass trinsfer limitations as in the case of the special fibers. Mechanical properties of the fiber do not significantly change when they are fabricated with zeolite Y microcapsules. Finally, fabrics knitted with yams of α-tocopheryl acetate-zeolite Y microcapsules state a significant presence of the additive after 100 washing machine cycles (30 °C, neutral soap). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23213985 Exemplaires
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Titre : Influence of deposition time on layer-by-layer growth of clay-based thin films Type de document : texte imprimé Auteurs : You-Hao Yang, Auteur ; Frank A. Malek, Auteur ; Jaime C. Grunlan, Auteur Année de publication : 2010 Article en page(s) : pp. 8501–8509 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Clay Résumé : The influence of deposition time on film growth of montmorillonite (MMT) or laponite (LAP) clay paired with branched polyethylenimine (BPEI) is studied here using layer-by-layer (LbL) assembly. Deposition times from 5 to 300 s in each ingredient were evaluated with respect to thickness, mass deposited, film structure, and oxygen barrier. Ellipsometry and quartz crystal microbalance show the BPEI/LAP system to be more dip-time dependent than the BPEI/MMT system because LAP platelets have a much smaller aspect ratio than MMT. Similar thickness is achieved for all recipes when only the BPEI deposition time is varied. Cross-sectional TEM images confirm thicker growth of BPEI/LAP in 300 s relative to 10 s. X-ray diffraction (XRD) suggests the gallery spacing between clay layers is insensitive to dip time, which is a key structural parameter linked to both mechanical and transport properties of these types of films. Additionally, oxygen transmission rates (OTR) are below the detection limit of commercial instrumentation ( ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100499x
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8501–8509[article] Influence of deposition time on layer-by-layer growth of clay-based thin films [texte imprimé] / You-Hao Yang, Auteur ; Frank A. Malek, Auteur ; Jaime C. Grunlan, Auteur . - 2010 . - pp. 8501–8509.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8501–8509
Mots-clés : Clay Résumé : The influence of deposition time on film growth of montmorillonite (MMT) or laponite (LAP) clay paired with branched polyethylenimine (BPEI) is studied here using layer-by-layer (LbL) assembly. Deposition times from 5 to 300 s in each ingredient were evaluated with respect to thickness, mass deposited, film structure, and oxygen barrier. Ellipsometry and quartz crystal microbalance show the BPEI/LAP system to be more dip-time dependent than the BPEI/MMT system because LAP platelets have a much smaller aspect ratio than MMT. Similar thickness is achieved for all recipes when only the BPEI deposition time is varied. Cross-sectional TEM images confirm thicker growth of BPEI/LAP in 300 s relative to 10 s. X-ray diffraction (XRD) suggests the gallery spacing between clay layers is insensitive to dip time, which is a key structural parameter linked to both mechanical and transport properties of these types of films. Additionally, oxygen transmission rates (OTR) are below the detection limit of commercial instrumentation ( ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100499x Exemplaires
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Titre : Preparation of hollow ZnO microspheres using poly(methyl methacrylate) as a template with supercritical CO2-ethanol s Type de document : texte imprimé Auteurs : Kiyoshi Matsuyama, Auteur ; Kenji Mishima, Auteur ; Takafumi Kato, Auteur Année de publication : 2010 Article en page(s) : pp. 8510–8517 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Microspheres Résumé : Hollow ZnO microspheres were prepared using poly(methyl methacrylate) (PMMA) as a template with the assistance of supercritical CO2-ethanol solution. A precursor solution of zinc nitrate (Zn(NO3)2·6H2O) was dissolved in supercritical CO2/ethanol mixtures and was impregnated on the surface of the PMMA template. After the removal of the PMMA template by calcination in air, hollow ZnO microspheres were obtained. The products were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), nitrogen adsorption−desorption experiments, and scanning electronic microscopy (SEM). Furthermore, the effects of experimental conditions, such as the concentration of precursor, calcination temperature, impregnation media, and operating temperature during the depressurization process, on the particle morphology were investigated. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100551t
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8510–8517[article] Preparation of hollow ZnO microspheres using poly(methyl methacrylate) as a template with supercritical CO2-ethanol s [texte imprimé] / Kiyoshi Matsuyama, Auteur ; Kenji Mishima, Auteur ; Takafumi Kato, Auteur . - 2010 . - pp. 8510–8517.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8510–8517
Mots-clés : Microspheres Résumé : Hollow ZnO microspheres were prepared using poly(methyl methacrylate) (PMMA) as a template with the assistance of supercritical CO2-ethanol solution. A precursor solution of zinc nitrate (Zn(NO3)2·6H2O) was dissolved in supercritical CO2/ethanol mixtures and was impregnated on the surface of the PMMA template. After the removal of the PMMA template by calcination in air, hollow ZnO microspheres were obtained. The products were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), nitrogen adsorption−desorption experiments, and scanning electronic microscopy (SEM). Furthermore, the effects of experimental conditions, such as the concentration of precursor, calcination temperature, impregnation media, and operating temperature during the depressurization process, on the particle morphology were investigated. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100551t Exemplaires
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Titre : Fabrication of biocompatible temperature- and pH-responsive magnetic nanoparticles and their reversible agglomeration in aqueous milieu Type de document : texte imprimé Auteurs : Liangrong Yang, Auteur ; Chen Guo, Auteur ; Lianwei Jia, Auteur Année de publication : 2010 Article en page(s) : pp. 8518–8525 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticles Aqueous milieu Résumé : A novel kind of biocompatible pH- and temperature-responsive magnetic nanoparticle consisting of iron oxide nanoparticles coated with pH-responsive chitosan oligosaccharide and temperature-responsive poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) block copolymer was developed. The particles were characterized by TEM, DLS, VSM, FTIR spectroscopy, and TGA. The results indicated that the self-aggregation of the prepared nanoparticles was not only caused by the thermoinduced self-assembly of the immobilized block copolymers, but also affected by the pH-induced charge property change of the particle surface. The self-assembled behaviors can be readily reversed by adjusting the pH or temperature value. Thus, the attractive properties of reversible and controllable dual-responsive self-assembly might endow the biocompatible magnetic nanoparticles with potential applications in biomedical fields such as DNA delivery, drug targeting, and tissue engineering. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100587e
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8518–8525[article] Fabrication of biocompatible temperature- and pH-responsive magnetic nanoparticles and their reversible agglomeration in aqueous milieu [texte imprimé] / Liangrong Yang, Auteur ; Chen Guo, Auteur ; Lianwei Jia, Auteur . - 2010 . - pp. 8518–8525.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8518–8525
Mots-clés : Nanoparticles Aqueous milieu Résumé : A novel kind of biocompatible pH- and temperature-responsive magnetic nanoparticle consisting of iron oxide nanoparticles coated with pH-responsive chitosan oligosaccharide and temperature-responsive poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) block copolymer was developed. The particles were characterized by TEM, DLS, VSM, FTIR spectroscopy, and TGA. The results indicated that the self-aggregation of the prepared nanoparticles was not only caused by the thermoinduced self-assembly of the immobilized block copolymers, but also affected by the pH-induced charge property change of the particle surface. The self-assembled behaviors can be readily reversed by adjusting the pH or temperature value. Thus, the attractive properties of reversible and controllable dual-responsive self-assembly might endow the biocompatible magnetic nanoparticles with potential applications in biomedical fields such as DNA delivery, drug targeting, and tissue engineering. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100587e Exemplaires
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Titre : Photoisomerization of norbornadiene to quadricyclane using transition metal doped TiO2 Type de document : texte imprimé Auteurs : Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xiangwen Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 8526–8531 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Photoisomerization Norbornadiene Résumé : Metal(V, Fe, Ce, Cu, Cr)-doped TiO2 were synthesized for the photoisomerization of norbornadiene. Characterizations indicate that V and Fe are located in the substitutional sites of TiO2, Ce ions dispersed in the interstitial sites, while Cr and Cu aggregated on the surface. The order of activity is Fe−TiO2 > V−TiO2 > Cr−TiO2 > Ce−TiO2 > TiO2 > Cu−TiO2, suggesting the local structure and type of dopant are crucial. Materials with various V and Fe content were further studied. Fe ions are well dispersed in TiO2 lattice even at high metal content, whereas many separated V2O5 phases are formed. The activity of V−TiO2 changes with V content and the optimal Ti/V ratio is 15, but the activity of Fe−TiO2 is independent of the metal content. Attributed to the high dispersion, Fe−TiO2 is much more active than V−TiO2. The photoreactivity is correlated with the surface lattice oxygen, and a mechanism is proposed to explain the photoisomerization and role of Fe dopant. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100841w
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8526–8531[article] Photoisomerization of norbornadiene to quadricyclane using transition metal doped TiO2 [texte imprimé] / Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xiangwen Zhang, Auteur . - 2010 . - pp. 8526–8531.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8526–8531
Mots-clés : Photoisomerization Norbornadiene Résumé : Metal(V, Fe, Ce, Cu, Cr)-doped TiO2 were synthesized for the photoisomerization of norbornadiene. Characterizations indicate that V and Fe are located in the substitutional sites of TiO2, Ce ions dispersed in the interstitial sites, while Cr and Cu aggregated on the surface. The order of activity is Fe−TiO2 > V−TiO2 > Cr−TiO2 > Ce−TiO2 > TiO2 > Cu−TiO2, suggesting the local structure and type of dopant are crucial. Materials with various V and Fe content were further studied. Fe ions are well dispersed in TiO2 lattice even at high metal content, whereas many separated V2O5 phases are formed. The activity of V−TiO2 changes with V content and the optimal Ti/V ratio is 15, but the activity of Fe−TiO2 is independent of the metal content. Attributed to the high dispersion, Fe−TiO2 is much more active than V−TiO2. The photoreactivity is correlated with the surface lattice oxygen, and a mechanism is proposed to explain the photoisomerization and role of Fe dopant. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100841w Exemplaires
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Titre : Improvement of wetting properties of colloid silica binders Type de document : texte imprimé Auteurs : Maria Morga, Auteur ; Grazyna Para, Auteur ; Zbigniew Adamczyk, Auteur Année de publication : 2010 Article en page(s) : pp 8532–8537 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Colloid silica Wetting properties Résumé : Wetting properties of colloid silica binders modified by addition of surfactants were investigated. Perfluorononanoic, an anionic surfactant, the nonionic fluorinated surfactant Zonyl FSO-100, the nonionic commercial surfactant Rokafenol, and their mixtures were studied. As a model silica binder, a 30% colloid dispersion of SiO2 in water was used, which was compared with the commercial binder Sizol, also based on colloid silica. The size of particles in these dispersions was determined by dynamic light scattering and by the atomic force microscopy imaging of particles deposited on mica. The zeta potential of particles was measured by microelectrophoresis. The dynamic surface tension and contact angles of binders on a paraffin substrate was determined by drop shape analysis. Our investigations showed that the Zonyl-FSO surfactant and its mixture with Rokafenol effectively reduced the dynamic contact angle to a value of 18°. Such low contact angles represent a significant improvement in comparison with commercial binders. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100772c
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp 8532–8537[article] Improvement of wetting properties of colloid silica binders [texte imprimé] / Maria Morga, Auteur ; Grazyna Para, Auteur ; Zbigniew Adamczyk, Auteur . - 2010 . - pp 8532–8537.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp 8532–8537
Mots-clés : Colloid silica Wetting properties Résumé : Wetting properties of colloid silica binders modified by addition of surfactants were investigated. Perfluorononanoic, an anionic surfactant, the nonionic fluorinated surfactant Zonyl FSO-100, the nonionic commercial surfactant Rokafenol, and their mixtures were studied. As a model silica binder, a 30% colloid dispersion of SiO2 in water was used, which was compared with the commercial binder Sizol, also based on colloid silica. The size of particles in these dispersions was determined by dynamic light scattering and by the atomic force microscopy imaging of particles deposited on mica. The zeta potential of particles was measured by microelectrophoresis. The dynamic surface tension and contact angles of binders on a paraffin substrate was determined by drop shape analysis. Our investigations showed that the Zonyl-FSO surfactant and its mixture with Rokafenol effectively reduced the dynamic contact angle to a value of 18°. Such low contact angles represent a significant improvement in comparison with commercial binders. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100772c Exemplaires
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Titre : Bitumen chemical foaming for asphalt paving applications Type de document : texte imprimé Auteurs : Virginia Carrera, Auteur ; Moises Garcia-Morales, Auteur ; Francisco J. Navarro, Auteur Année de publication : 2010 Article en page(s) : pp. 8538–8543 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Bitumen chemical Résumé : As an alternative to traditional hot-mix asphalt paving, bitumen foaming technologies have been extensively used in road recycling over the last decades. However, much more work on the use of foam-enhancing chemical agents is needed. This research deals with the influence that temperature and processing protocol exert on the bitumen foaming process promoted by a poly(propylene glycol) functionalized with a polymeric 4,4′-diphenylmethane diisocyanate. Likewise, rheological and microstructural characterizations have been carried out on the modified bituminous residues obtained after foaming. From the experimental results obtained, it may be concluded that reactive isocyanate-based polymers can be used to obtain foamed binders with different foamability and stability characteristics. On the other hand, both foaming and bitumen modification are seen to occur simultaneously, as a result of bitumen/polymer reactions involving water. Finally, dynamic shear tests and atomic force microscopy observations reveal very different degrees of modification, which depend on the colloidal features of the as-received bitumen. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101136f
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8538–8543[article] Bitumen chemical foaming for asphalt paving applications [texte imprimé] / Virginia Carrera, Auteur ; Moises Garcia-Morales, Auteur ; Francisco J. Navarro, Auteur . - 2010 . - pp. 8538–8543.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8538–8543
Mots-clés : Bitumen chemical Résumé : As an alternative to traditional hot-mix asphalt paving, bitumen foaming technologies have been extensively used in road recycling over the last decades. However, much more work on the use of foam-enhancing chemical agents is needed. This research deals with the influence that temperature and processing protocol exert on the bitumen foaming process promoted by a poly(propylene glycol) functionalized with a polymeric 4,4′-diphenylmethane diisocyanate. Likewise, rheological and microstructural characterizations have been carried out on the modified bituminous residues obtained after foaming. From the experimental results obtained, it may be concluded that reactive isocyanate-based polymers can be used to obtain foamed binders with different foamability and stability characteristics. On the other hand, both foaming and bitumen modification are seen to occur simultaneously, as a result of bitumen/polymer reactions involving water. Finally, dynamic shear tests and atomic force microscopy observations reveal very different degrees of modification, which depend on the colloidal features of the as-received bitumen. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101136f Exemplaires
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Titre : Effect of pulp fines on the dye−fiber interactions during the color-shading process Type de document : texte imprimé Auteurs : Hongbin Liu, Auteur ; Shuhui Yang, Auteur ; Yonghao Ni, Auteur Année de publication : 2010 Article en page(s) : pp. 8544–8549 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Paper properties Résumé : Fines play a very important role in the papermaking process and paper properties. High-yield pulp (HYP) contains a large amount of higher specific surface area fines, which may lead to the absorption of more dye at the wet end section. Better understanding of the dye−fines interaction will help improve the dye efficiency in HYP-containing furnish. This study was focused on the fines from high-yield pulp and hardwood bleached kraft pulp (HBKP) on optical properties, particularly on the CIE (Commission Internationale d’Eclairage) whiteness and b* (negative values indicate blue, and positive values indicate yellow). The characteristics of both HYP fines and HBKP fines were presented, and their effects on dyeing (color-shading) process were investigated. Fines have a higher specific surface area and more dissolved and colloidal substances (DCS) than do the fibers. It was found that for a system made of HYP fibers, HYP fines had a negative effect, while HBKP fines had a positive effect on the color shading process. For a system made of HBKP fibers, a low content (5%) of HYP fines can increase the dye effectiveness, although when the HYP fine content increased further, the dye performance showed a decrease; HBKP fines retarded the dye effectiveness for the HBKP fiber system. For the mixture of HYP fines and HBKP fines, the turbidity measurement was used to explain the interactions between the HYP fines and HBKP fines. The dyes and HYP fines can form complexes, which then retain in the fiber network, thus improving the dye effectiveness and resulting in a higher CIE whiteness and lower b* of the paper sheets. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101169s
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8544–8549[article] Effect of pulp fines on the dye−fiber interactions during the color-shading process [texte imprimé] / Hongbin Liu, Auteur ; Shuhui Yang, Auteur ; Yonghao Ni, Auteur . - 2010 . - pp. 8544–8549.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8544–8549
Mots-clés : Paper properties Résumé : Fines play a very important role in the papermaking process and paper properties. High-yield pulp (HYP) contains a large amount of higher specific surface area fines, which may lead to the absorption of more dye at the wet end section. Better understanding of the dye−fines interaction will help improve the dye efficiency in HYP-containing furnish. This study was focused on the fines from high-yield pulp and hardwood bleached kraft pulp (HBKP) on optical properties, particularly on the CIE (Commission Internationale d’Eclairage) whiteness and b* (negative values indicate blue, and positive values indicate yellow). The characteristics of both HYP fines and HBKP fines were presented, and their effects on dyeing (color-shading) process were investigated. Fines have a higher specific surface area and more dissolved and colloidal substances (DCS) than do the fibers. It was found that for a system made of HYP fibers, HYP fines had a negative effect, while HBKP fines had a positive effect on the color shading process. For a system made of HBKP fibers, a low content (5%) of HYP fines can increase the dye effectiveness, although when the HYP fine content increased further, the dye performance showed a decrease; HBKP fines retarded the dye effectiveness for the HBKP fiber system. For the mixture of HYP fines and HBKP fines, the turbidity measurement was used to explain the interactions between the HYP fines and HBKP fines. The dyes and HYP fines can form complexes, which then retain in the fiber network, thus improving the dye effectiveness and resulting in a higher CIE whiteness and lower b* of the paper sheets. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101169s Exemplaires
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Titre : Surface and friction behavior of a silicone surfactant adsorbed on model textiles substrates Type de document : texte imprimé Auteurs : Xiaomeng Liu, Auteur ; Junlong Song, Auteur ; Dong Wu, Auteur Année de publication : 2010 Article en page(s) : pp. 8550–8557 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Silicone surfactant Résumé : This study reports on interactions of an amphiphilic block copolymer of polyalkylene oxide-modified poly(dimethylsiloxane) with thin films of polypropylene (PP), polyethylene terephthalate (PET), and nylon, as well as with reference hydrophilic silica surfaces. The dynamics of adsorption, adsorbed mass, and viscoelasticity of the adsorbed layer are quantified by using a quartz crystal microbalance, while boundary layer lubrication behaviors are studied by using lateral force microscopy. Driven by hydrophobic interactions, the silicone surfactant adsorbs following a Langmuir isotherm and forms strongly adsorbed layers on the polymer surfaces with an areal mass directly related to the hydrophobicity of the substrate. The self-assembled silicone surfactant molecules improve significantly wettability and lower friction. The results reported herein will broaden our understanding of lubrication phenomena in textile and fiber processing applications. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012213
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8550–8557[article] Surface and friction behavior of a silicone surfactant adsorbed on model textiles substrates [texte imprimé] / Xiaomeng Liu, Auteur ; Junlong Song, Auteur ; Dong Wu, Auteur . - 2010 . - pp. 8550–8557.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8550–8557
Mots-clés : Silicone surfactant Résumé : This study reports on interactions of an amphiphilic block copolymer of polyalkylene oxide-modified poly(dimethylsiloxane) with thin films of polypropylene (PP), polyethylene terephthalate (PET), and nylon, as well as with reference hydrophilic silica surfaces. The dynamics of adsorption, adsorbed mass, and viscoelasticity of the adsorbed layer are quantified by using a quartz crystal microbalance, while boundary layer lubrication behaviors are studied by using lateral force microscopy. Driven by hydrophobic interactions, the silicone surfactant adsorbs following a Langmuir isotherm and forms strongly adsorbed layers on the polymer surfaces with an areal mass directly related to the hydrophobicity of the substrate. The self-assembled silicone surfactant molecules improve significantly wettability and lower friction. The results reported herein will broaden our understanding of lubrication phenomena in textile and fiber processing applications. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012213 Exemplaires
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Titre : Subspace approach to identification of step-response model from closed-loop data Type de document : texte imprimé Auteurs : Nima Danesh Pour, Auteur ; Biao Huang, Auteur ; Sirish L. Shah, Auteur Année de publication : 2010 Article en page(s) : pp. 8558–8567 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Silicone surfactant Résumé : We investigate direct estimation of step-response models from closed-loop data using subspace identification. Necessary information concerning impulse-response coefficients is embedded in subspace matrices. Therefore, the step-response coefficients can be directly obtained from this matrix by integration without the need of extracting state space models first, as the conventional subspace identification does. Since the estimated subspace matrix contains more than one set of impulse-response coefficients, a question arises about how to best synthesize them to obtain an optimal estimate of the impulse-response coefficients and subsequently the step-response coefficients. For this purpose, a reformulation of the subspace identification problem is required for which the variance of all elements in the related subspace matrix can be evaluated. The calculated variances are then used to perform a weighted averaging on the estimated impulse-response coefficients to attenuate the noise influence on the final step-response model estimation. Monte Carlo simulations and pilot-scale experiments are provided to illustrate the proposed method. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012213
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8558–8567[article] Subspace approach to identification of step-response model from closed-loop data [texte imprimé] / Nima Danesh Pour, Auteur ; Biao Huang, Auteur ; Sirish L. Shah, Auteur . - 2010 . - pp. 8558–8567.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8558–8567
Mots-clés : Silicone surfactant Résumé : We investigate direct estimation of step-response models from closed-loop data using subspace identification. Necessary information concerning impulse-response coefficients is embedded in subspace matrices. Therefore, the step-response coefficients can be directly obtained from this matrix by integration without the need of extracting state space models first, as the conventional subspace identification does. Since the estimated subspace matrix contains more than one set of impulse-response coefficients, a question arises about how to best synthesize them to obtain an optimal estimate of the impulse-response coefficients and subsequently the step-response coefficients. For this purpose, a reformulation of the subspace identification problem is required for which the variance of all elements in the related subspace matrix can be evaluated. The calculated variances are then used to perform a weighted averaging on the estimated impulse-response coefficients to attenuate the noise influence on the final step-response model estimation. Monte Carlo simulations and pilot-scale experiments are provided to illustrate the proposed method. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012213 Exemplaires
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Titre : Numerical analysis of a periodically forced dyeing process Type de document : texte imprimé Auteurs : Erasmo Mancusi, Auteur ; Selene Guelli Ulson de Souza, Auteur ; Antônio Augusto Ulson de Souza, Auteur Année de publication : 2010 Article en page(s) : pp. 8568–8574 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dyeing Process Résumé : In this work, a forcing strategy based on a cyclic flow reversal of a dyeing process of bobbin threads is investigated through numerical simulation. Convection, dispersion, and adsorption of dye on the threads are modeled considering that the system is operated by a cyclic reversal of the flow direction through the bobbins. The periodic forcing is modeled by an ad hoc discontinuous periodic function, and a mathematical model that takes it into account is developed. The mathematical model is a set of partial differential equations that is reduced to a system of ordinary differential equations by an orthogonal collocation on finite elements technique. The comparison between forced and unforced processes has been carried out analyzing the dye distribution factor and the total amount of adsorbed dye during the transient regime for both of the processes. The main effect of periodic forcing is to enhance a more even dye distribution. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017012
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8568–8574[article] Numerical analysis of a periodically forced dyeing process [texte imprimé] / Erasmo Mancusi, Auteur ; Selene Guelli Ulson de Souza, Auteur ; Antônio Augusto Ulson de Souza, Auteur . - 2010 . - pp. 8568–8574.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8568–8574
Mots-clés : Dyeing Process Résumé : In this work, a forcing strategy based on a cyclic flow reversal of a dyeing process of bobbin threads is investigated through numerical simulation. Convection, dispersion, and adsorption of dye on the threads are modeled considering that the system is operated by a cyclic reversal of the flow direction through the bobbins. The periodic forcing is modeled by an ad hoc discontinuous periodic function, and a mathematical model that takes it into account is developed. The mathematical model is a set of partial differential equations that is reduced to a system of ordinary differential equations by an orthogonal collocation on finite elements technique. The comparison between forced and unforced processes has been carried out analyzing the dye distribution factor and the total amount of adsorbed dye during the transient regime for both of the processes. The main effect of periodic forcing is to enhance a more even dye distribution. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017012 Exemplaires
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Titre : Improved fault diagnosis using dynamic kernel scatter-difference-based discriminant analysis Type de document : texte imprimé Auteurs : C. Sumana, Auteur ; Bhushan Mani, Auteur ; Ch. Venkateswarlu, Auteur Année de publication : 2010 Article en page(s) : pp. 8575–8586 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Discriminant analysis Résumé : Performing fault diagnosis of nonlinear processes involving data with serial correlations, nonlinearities, and overlapping signatures is a challenging task. This article proposes a dynamic kernel scatter-difference-based discriminant analysis (DKSDA) for resolving such complex data so as to improve fault resolution for efficient diagnosis. The DKSDA considers a suitably time lagged extension of the original data and allows its transformation into high-dimensional feature space via nonlinear kernel functions, and then solves the scatter difference form of the Fisher criterion. This fault diagnosis method successfully addresses the problem of dynamic correlations that are typically associated with chemical process measurements and efficiently captures the nonlinearities in data. A systematic procedure is proposed to configure the interactive parameters, namely, the number of lags, the scatter difference, and the kernel width, which govern the performance of DKSDA. The procedure involves a two-dimensional grid search at two levels to minimize a performance criterion defined in terms of the misclassification of DKSDA scores evaluated by cross validation using the nearest mean classifiers. The performance of the proposed method is evaluated by applying it for the diagnosis of overlapping and nonoverlapping faults of Tennessee Eastman challenge process and the overlapping faults of a general multivariable nonlinear dynamic process. The comparison of results with the recently reported methods demonstrates the superior performance of DKSDA for nonlinear process fault diagnosis involving complex overlapping data. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902019h
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8575–8586[article] Improved fault diagnosis using dynamic kernel scatter-difference-based discriminant analysis [texte imprimé] / C. Sumana, Auteur ; Bhushan Mani, Auteur ; Ch. Venkateswarlu, Auteur . - 2010 . - pp. 8575–8586.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8575–8586
Mots-clés : Discriminant analysis Résumé : Performing fault diagnosis of nonlinear processes involving data with serial correlations, nonlinearities, and overlapping signatures is a challenging task. This article proposes a dynamic kernel scatter-difference-based discriminant analysis (DKSDA) for resolving such complex data so as to improve fault resolution for efficient diagnosis. The DKSDA considers a suitably time lagged extension of the original data and allows its transformation into high-dimensional feature space via nonlinear kernel functions, and then solves the scatter difference form of the Fisher criterion. This fault diagnosis method successfully addresses the problem of dynamic correlations that are typically associated with chemical process measurements and efficiently captures the nonlinearities in data. A systematic procedure is proposed to configure the interactive parameters, namely, the number of lags, the scatter difference, and the kernel width, which govern the performance of DKSDA. The procedure involves a two-dimensional grid search at two levels to minimize a performance criterion defined in terms of the misclassification of DKSDA scores evaluated by cross validation using the nearest mean classifiers. The performance of the proposed method is evaluated by applying it for the diagnosis of overlapping and nonoverlapping faults of Tennessee Eastman challenge process and the overlapping faults of a general multivariable nonlinear dynamic process. The comparison of results with the recently reported methods demonstrates the superior performance of DKSDA for nonlinear process fault diagnosis involving complex overlapping data. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902019h Exemplaires
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Titre : Methodology for stable dynamic simulation of a LNG pipe under two-phase-flow generation Type de document : texte imprimé Auteurs : Youngsub Lim, Auteur ; Chul-Jin Lee, Auteur ; Sangho Lee, Auteur Année de publication : 2010 Article en page(s) : pp. 8587–8592 Note générale : Industrial chemistry Mots-clés : Dynamic simulation Résumé : The results of dynamic simulations can become unstable because of a steep change in the calculated variables. In particular, when liquefied natural gas (LNG) begins to vaporize and a two-phase flow is generated, the simulation results can become violently oscillatory because of the significant volume difference between natural gas in the vapor phase and LNG in the liquid phase. To ensure more stable simulation results, we developed a methodology for replacing a unit module selectively. When LNG started to vaporize, the unit module at the point where the two-phase flow was first generated was replaced by a more stable unit module. This methodology was evaluated through a case study of a LNG pipeline model and led to more stable simulation results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902076t
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8587–8592[article] Methodology for stable dynamic simulation of a LNG pipe under two-phase-flow generation [texte imprimé] / Youngsub Lim, Auteur ; Chul-Jin Lee, Auteur ; Sangho Lee, Auteur . - 2010 . - pp. 8587–8592.
Industrial chemistry
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8587–8592
Mots-clés : Dynamic simulation Résumé : The results of dynamic simulations can become unstable because of a steep change in the calculated variables. In particular, when liquefied natural gas (LNG) begins to vaporize and a two-phase flow is generated, the simulation results can become violently oscillatory because of the significant volume difference between natural gas in the vapor phase and LNG in the liquid phase. To ensure more stable simulation results, we developed a methodology for replacing a unit module selectively. When LNG started to vaporize, the unit module at the point where the two-phase flow was first generated was replaced by a more stable unit module. This methodology was evaluated through a case study of a LNG pipeline model and led to more stable simulation results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902076t Exemplaires
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Titre : Experimental verification of bilevel optimizing control for SMB technology Type de document : texte imprimé Auteurs : Kiwoong Kim, Auteur ; Jin-Il Kim, Auteur ; Huiyong Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 8593–8600 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Optimizing control technique Résumé : An experimental study has been conducted to evaluate the bilevel optimizing control technique for simulated moving beds (SMBs) that was proposed in a previous article (Kim et al. Ind. Eng. Chem. Res. 2010, 49, 3689−3699). Off-line optimization provides optimum time-varying flow rates for feed and desorbent in the upper level, and repetitive model-based predictive control (RMPC) is performed for regulation of the extract and raffinate purities in the lower level. Experiments have been carried out in a four-zone SMB system packed with Dow 50WX4 400-mesh resin to separate l-ribose and l-arabinose at 99.7 vol% from their mixture dissolved in water. The optimizing control technique was implemented just as in the numerical study in the previous work, except for some minor customization. In the experiments, RMPC revealed quite satisfactory tracking and disturbance rejection performance. Optimization resulted in a 45% increase in productivity and a 12% decrease in desorbent consumption from an arbitrary initial point, and the cascaded RMPC law tightly maintained the product purities at their set points by effectively compensating the changes in the feed and desorbent flow rates. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000218
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8593–8600[article] Experimental verification of bilevel optimizing control for SMB technology [texte imprimé] / Kiwoong Kim, Auteur ; Jin-Il Kim, Auteur ; Huiyong Kim, Auteur . - 2010 . - pp. 8593–8600.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8593–8600
Mots-clés : Optimizing control technique Résumé : An experimental study has been conducted to evaluate the bilevel optimizing control technique for simulated moving beds (SMBs) that was proposed in a previous article (Kim et al. Ind. Eng. Chem. Res. 2010, 49, 3689−3699). Off-line optimization provides optimum time-varying flow rates for feed and desorbent in the upper level, and repetitive model-based predictive control (RMPC) is performed for regulation of the extract and raffinate purities in the lower level. Experiments have been carried out in a four-zone SMB system packed with Dow 50WX4 400-mesh resin to separate l-ribose and l-arabinose at 99.7 vol% from their mixture dissolved in water. The optimizing control technique was implemented just as in the numerical study in the previous work, except for some minor customization. In the experiments, RMPC revealed quite satisfactory tracking and disturbance rejection performance. Optimization resulted in a 45% increase in productivity and a 12% decrease in desorbent consumption from an arbitrary initial point, and the cascaded RMPC law tightly maintained the product purities at their set points by effectively compensating the changes in the feed and desorbent flow rates. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000218 Exemplaires
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Titre : Wastewater treatment plant synthesis and design : combined biological nitrogen and phosphorus removal Type de document : texte imprimé Auteurs : Noelia Alasino, Auteur ; Miguel C. Mussati, Auteur ; Nicolas J. Scenna, Auteur Année de publication : 2010 Article en page(s) : pp. 8601–8612 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Wastewater treatment Résumé : In the present work, a previous superstructure model developed for simultaneous optimization of the process configuration and equipment dimensions, i.e., optimal process synthesis and design and the operation conditions of activated sludge wastewater treatment plants, is extended to account for phosphorus as well as nitrogen removal. Along the activated sludge treatment process, the wastewater stream is exposed to different environmental conditions (anaerobic, anoxic, and aerated zones) in order to facilitate the different microbiological processes such as the release and uptake of phosphorus and the nitrification/denitrification processes. The Activated Sludge Model No. 3 extended with the Bio-P module for computing biological phosphorus removal is used to model the reaction compartments and the Takàcs model for representing the secondary settler. The performance criterion selected is the minimization of the net present value that includes investment and operating costs while verifying compliance with the effluent permitted limits. The problem is posed as a NLP problem, specifically a nonlinear programming problem with discontinuous derivatives DNLP. The optimization model is implemented and solved using a General Algebraic Modeling System, GAMS. Optimal configurations and designs obtained for several case studies are reported and discussed. The model itself and the resolution methodology prove to be robust and flexible enough to solve efficiently scenarios with a wide range of operation conditions, embedding conventional and nonconventional process configurations. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000482
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8601–8612[article] Wastewater treatment plant synthesis and design : combined biological nitrogen and phosphorus removal [texte imprimé] / Noelia Alasino, Auteur ; Miguel C. Mussati, Auteur ; Nicolas J. Scenna, Auteur . - 2010 . - pp. 8601–8612.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8601–8612
Mots-clés : Wastewater treatment Résumé : In the present work, a previous superstructure model developed for simultaneous optimization of the process configuration and equipment dimensions, i.e., optimal process synthesis and design and the operation conditions of activated sludge wastewater treatment plants, is extended to account for phosphorus as well as nitrogen removal. Along the activated sludge treatment process, the wastewater stream is exposed to different environmental conditions (anaerobic, anoxic, and aerated zones) in order to facilitate the different microbiological processes such as the release and uptake of phosphorus and the nitrification/denitrification processes. The Activated Sludge Model No. 3 extended with the Bio-P module for computing biological phosphorus removal is used to model the reaction compartments and the Takàcs model for representing the secondary settler. The performance criterion selected is the minimization of the net present value that includes investment and operating costs while verifying compliance with the effluent permitted limits. The problem is posed as a NLP problem, specifically a nonlinear programming problem with discontinuous derivatives DNLP. The optimization model is implemented and solved using a General Algebraic Modeling System, GAMS. Optimal configurations and designs obtained for several case studies are reported and discussed. The model itself and the resolution methodology prove to be robust and flexible enough to solve efficiently scenarios with a wide range of operation conditions, embedding conventional and nonconventional process configurations. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000482 Exemplaires
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Titre : Dynamic bayesian approach for control loop diagnosis with underlying mode dependency Type de document : texte imprimé Auteurs : Fei Qi, Auteur ; Biao Huang, Auteur Année de publication : 2010 Article en page(s) : pp. 8613–8623 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dynamic bayesian Résumé : In this article, first, a hidden Markov model is built to address the temporal mode dependency problem in control loop diagnosis. A data-driven algorithm is developed to estimate the mode transition probability. The new solution to mode dependency is then further synthesized with the solution to evidence dependency to develop a recursive autoregressive hidden Markov model for online control loop diagnosis. When both the mode and evidence transition information sets are considered, the temporal information is effectively synthesized under the Bayesian framework. A simulated distillation column example and a pilot-scale experiment example are investigated to demonstrate the ability of the proposed diagnosis approach. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100058y
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8613–8623[article] Dynamic bayesian approach for control loop diagnosis with underlying mode dependency [texte imprimé] / Fei Qi, Auteur ; Biao Huang, Auteur . - 2010 . - pp. 8613–8623.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8613–8623
Mots-clés : Dynamic bayesian Résumé : In this article, first, a hidden Markov model is built to address the temporal mode dependency problem in control loop diagnosis. A data-driven algorithm is developed to estimate the mode transition probability. The new solution to mode dependency is then further synthesized with the solution to evidence dependency to develop a recursive autoregressive hidden Markov model for online control loop diagnosis. When both the mode and evidence transition information sets are considered, the temporal information is effectively synthesized under the Bayesian framework. A simulated distillation column example and a pilot-scale experiment example are investigated to demonstrate the ability of the proposed diagnosis approach. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100058y Exemplaires
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Titre : Selection of optimal, controlled variables for the TEALARC LNG process Type de document : texte imprimé Auteurs : Finn Are Michelsen, Auteur ; Berit Floor Lund, Auteur ; Ivar Johan Halvorsen, Auteur Année de publication : 2010 Article en page(s) : pp. 8624–8632 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : LNG process Résumé : This article shows how controlled variables (CVs) of the regulatory control layer in a liquefied natural gas (LNG) plant can be chosen as linear combinations of measurements using self-optimizing control principles. By self-optimizing control, the CVs are chosen such that the set points of the CVs remain close to steady-state optimal despite disturbances, thus reducing the need for online reoptimization. Several methods for calculation of linear combinations within this framework are compared. Self-optimizing control design can also be used in the process design phase to place measurements by reducing a maximum candidate set of measurements to a best possible subset of measurements giving an acceptable loss. This article proposes a relatively simple method for successive selection (SS) of measurements and compares this approach to a more comprehensive branch-and-bound (BB) method for selection of measurements. The results indicate that, although the BB method gives lower average losses for very small subsets, the methods are comparable with respect to average losses for medium and large subsets, and the SS method outperforms the BB method in terms of computational load. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100081j
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8624–8632[article] Selection of optimal, controlled variables for the TEALARC LNG process [texte imprimé] / Finn Are Michelsen, Auteur ; Berit Floor Lund, Auteur ; Ivar Johan Halvorsen, Auteur . - 2010 . - pp. 8624–8632.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8624–8632
Mots-clés : LNG process Résumé : This article shows how controlled variables (CVs) of the regulatory control layer in a liquefied natural gas (LNG) plant can be chosen as linear combinations of measurements using self-optimizing control principles. By self-optimizing control, the CVs are chosen such that the set points of the CVs remain close to steady-state optimal despite disturbances, thus reducing the need for online reoptimization. Several methods for calculation of linear combinations within this framework are compared. Self-optimizing control design can also be used in the process design phase to place measurements by reducing a maximum candidate set of measurements to a best possible subset of measurements giving an acceptable loss. This article proposes a relatively simple method for successive selection (SS) of measurements and compares this approach to a more comprehensive branch-and-bound (BB) method for selection of measurements. The results indicate that, although the BB method gives lower average losses for very small subsets, the methods are comparable with respect to average losses for medium and large subsets, and the SS method outperforms the BB method in terms of computational load. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100081j Exemplaires
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Titre : Sustainability assessment of industrial systems under uncertainty : a fuzzy logic based approach to short-term to midterm predictions Type de document : texte imprimé Auteurs : Cristina Piluso, Auteur ; Jennifer Huang, Auteur ; Zheng Liu, Auteur Année de publication : 2010 Article en page(s) : pp. 8633–8643 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Industrial Systems Résumé : The sustainability assessment of industrial systems is always a very challenging task due to the existence of various types of uncertainties that are associated with the available data, assessable information, possessed knowledge, and problem understanding, etc. This paper introduces a fuzzy logic based approach for the effective short- and long-term assessment of industrial sustainability under the restrictions of aleatory and epistemic uncertainties. A comprehensive study on a metal-finishing-centered industrial zone is illustrated to show the efficacy of the introduced methodology. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100164r
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8633–8643[article] Sustainability assessment of industrial systems under uncertainty : a fuzzy logic based approach to short-term to midterm predictions [texte imprimé] / Cristina Piluso, Auteur ; Jennifer Huang, Auteur ; Zheng Liu, Auteur . - 2010 . - pp. 8633–8643.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8633–8643
Mots-clés : Industrial Systems Résumé : The sustainability assessment of industrial systems is always a very challenging task due to the existence of various types of uncertainties that are associated with the available data, assessable information, possessed knowledge, and problem understanding, etc. This paper introduces a fuzzy logic based approach for the effective short- and long-term assessment of industrial sustainability under the restrictions of aleatory and epistemic uncertainties. A comprehensive study on a metal-finishing-centered industrial zone is illustrated to show the efficacy of the introduced methodology. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100164r Exemplaires
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Titre : Control variance amplification in linear time invariant decentralized supply chains : a minimum variance control perspective Type de document : texte imprimé Auteurs : Hua Xu, Auteur ; Gang Rong, Auteur ; Yiping Feng, Auteur Année de publication : 2010 Article en page(s) : pp. 8644–8656 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Supply chains Résumé : This paper addresses demand uncertainty and its propagation in supply chains. The supply chain is considered as a linear time invariant (LTI) system driven by stochastic customer demand. Under general ARMA demand patterns and arbitrary lead times, a unified and structured framework based on the classical minimum variance control theory is proposed for decentralized supply chain management (SCM). Optimal forecasting, the traditional order-up-to policy and the generalized order-up-to policy are directly derived according to the minimum variance criterion. Given these strategies, stochastic properties of the supply chain are studied using LTI system theory in both the time and the frequency domain. Findings from previous literature are reinterpreted from a control-theory-oriented perspective, and new characteristics of the generalized order-up-to policy are deduced and analyzed. On the basis of the statistical analysis, an optimization model is constructed to minimize the variable operation costs which are related to the parameters of the SCM strategies. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100167u
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8644–8656[article] Control variance amplification in linear time invariant decentralized supply chains : a minimum variance control perspective [texte imprimé] / Hua Xu, Auteur ; Gang Rong, Auteur ; Yiping Feng, Auteur . - 2010 . - pp. 8644–8656.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8644–8656
Mots-clés : Supply chains Résumé : This paper addresses demand uncertainty and its propagation in supply chains. The supply chain is considered as a linear time invariant (LTI) system driven by stochastic customer demand. Under general ARMA demand patterns and arbitrary lead times, a unified and structured framework based on the classical minimum variance control theory is proposed for decentralized supply chain management (SCM). Optimal forecasting, the traditional order-up-to policy and the generalized order-up-to policy are directly derived according to the minimum variance criterion. Given these strategies, stochastic properties of the supply chain are studied using LTI system theory in both the time and the frequency domain. Findings from previous literature are reinterpreted from a control-theory-oriented perspective, and new characteristics of the generalized order-up-to policy are deduced and analyzed. On the basis of the statistical analysis, an optimization model is constructed to minimize the variable operation costs which are related to the parameters of the SCM strategies. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100167u Exemplaires
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Titre : Single-stage scheduling of multiproduct batch plants : an edible-oil deodorizer case study Type de document : texte imprimé Auteurs : Songsong Liu, Auteur ; Jose M. Pinto, Auteur ; Lazaros G. Papageorgiou, Auteur Année de publication : 2010 Article en page(s) : pp. 8657–8669 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Edible oil deodorizer Résumé : This article considers the short-term scheduling of a single-stage batch edible-oil deodorizer that can process multiple products in several product groups. Sequence-dependent changeovers occur when switching from one product group to another. Based on the incorporation of products into product groups, mixed integer linear programming (MILP) models are proposed for two scenarios, with and without backlogs. Then, the models are successfully applied to a real-world case with 70 product orders over a 128-h planning horizon. Compared with a literature model developed for a similar problem, the proposed models exhibit significantly better performance. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002137#afn2
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8657–8669[article] Single-stage scheduling of multiproduct batch plants : an edible-oil deodorizer case study [texte imprimé] / Songsong Liu, Auteur ; Jose M. Pinto, Auteur ; Lazaros G. Papageorgiou, Auteur . - 2010 . - pp. 8657–8669.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8657–8669
Mots-clés : Edible oil deodorizer Résumé : This article considers the short-term scheduling of a single-stage batch edible-oil deodorizer that can process multiple products in several product groups. Sequence-dependent changeovers occur when switching from one product group to another. Based on the incorporation of products into product groups, mixed integer linear programming (MILP) models are proposed for two scenarios, with and without backlogs. Then, the models are successfully applied to a real-world case with 70 product orders over a 128-h planning horizon. Compared with a literature model developed for a similar problem, the proposed models exhibit significantly better performance. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002137#afn2 Exemplaires
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Titre : Rigorous separation design. 2. : network design solutions for mixtures with various volatility differences and feed compositions Type de document : texte imprimé Auteurs : Seon B. Kim, Auteur ; Andreas A. Linninger, Auteur Année de publication : 2010 Article en page(s) : pp. 8670–8684 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Rigorous flow sheet synthesis Résumé : This article presents progress in the computer-aided synthesis of energy-efficient complex column networks based on the automatic temperature collocation algorithm. Three prefractionating complex networks are employed to split several quaternary mixtures into four almost-pure end products. Network solutions for two different mixtures with different difficulties of separation as well as various feed compositions are presented. Twelve network designs, all satisfying stringent product quality requirements, but with different energy demands and capital costs, are laid out in detail. The design computations with the temperature collocation methodology are demonstrated to agree closely with rigorous mass, equilibrium, summation, and heat computations verified with the industrial-standard flow sheet simulator AspenPlus. In fact, detailed design specifications were so accurate that their use to initialize AspenPlus flow sheet simulations leads to convergence in a few iterations to essentially the same end products. The success of the method demonstrates that rigorous solutions to separation problems can be obtained in a fraction of valuable engineering design time by computer methods. The automatic and rigorous flow sheet synthesis is apt to systematically address process design problems such as the synthesis of energy-efficient separation networks, the layout of biorefineries with novel feedstocks, or a sustainable process for reduction of greenhouse gases emissions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100355c
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8670–8684[article] Rigorous separation design. 2. : network design solutions for mixtures with various volatility differences and feed compositions [texte imprimé] / Seon B. Kim, Auteur ; Andreas A. Linninger, Auteur . - 2010 . - pp. 8670–8684.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8670–8684
Mots-clés : Rigorous flow sheet synthesis Résumé : This article presents progress in the computer-aided synthesis of energy-efficient complex column networks based on the automatic temperature collocation algorithm. Three prefractionating complex networks are employed to split several quaternary mixtures into four almost-pure end products. Network solutions for two different mixtures with different difficulties of separation as well as various feed compositions are presented. Twelve network designs, all satisfying stringent product quality requirements, but with different energy demands and capital costs, are laid out in detail. The design computations with the temperature collocation methodology are demonstrated to agree closely with rigorous mass, equilibrium, summation, and heat computations verified with the industrial-standard flow sheet simulator AspenPlus. In fact, detailed design specifications were so accurate that their use to initialize AspenPlus flow sheet simulations leads to convergence in a few iterations to essentially the same end products. The success of the method demonstrates that rigorous solutions to separation problems can be obtained in a fraction of valuable engineering design time by computer methods. The automatic and rigorous flow sheet synthesis is apt to systematically address process design problems such as the synthesis of energy-efficient separation networks, the layout of biorefineries with novel feedstocks, or a sustainable process for reduction of greenhouse gases emissions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100355c Exemplaires
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Titre : Nonlinear soft sensor development based on relevance vector machine Type de document : texte imprimé Auteurs : Zhiqiang Ge, Auteur ; Zhihuan Song, Auteur Année de publication : 2010 Article en page(s) : pp. 8685–8693 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nonlinear soft sensor Résumé : This paper proposes an effective nonlinear soft sensor based on relevance vector machine (RVM), which was originally proposed in the machine learning area. Compared to the widely used support vector machine (SVM) and least-squares support vector machine (LSSVM) based soft sensors, RVM gives a more sparse model structure, which can greatly reduce computational complexity for online prediction. While SVM/LSSVM can only provide a point estimation of the prediction result, RVM gives a probabilistic prediction result, which is more sophisticated for the soft sensor application. Furthermore, RVM can successfully avoid several drawbacks of the traditional support vector machine type method, such as kernel function limitation, parameter tuning complexity, and etc. Due to the advantages of RVM, a practical application of this method is made for soft sensor modeling in this paper. To evaluate the performance of the developed soft sensor, two case studies are demonstrated, which both support that RVM performs much better than other methods for soft sensing. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101146d
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8685–8693[article] Nonlinear soft sensor development based on relevance vector machine [texte imprimé] / Zhiqiang Ge, Auteur ; Zhihuan Song, Auteur . - 2010 . - pp. 8685–8693.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8685–8693
Mots-clés : Nonlinear soft sensor Résumé : This paper proposes an effective nonlinear soft sensor based on relevance vector machine (RVM), which was originally proposed in the machine learning area. Compared to the widely used support vector machine (SVM) and least-squares support vector machine (LSSVM) based soft sensors, RVM gives a more sparse model structure, which can greatly reduce computational complexity for online prediction. While SVM/LSSVM can only provide a point estimation of the prediction result, RVM gives a probabilistic prediction result, which is more sophisticated for the soft sensor application. Furthermore, RVM can successfully avoid several drawbacks of the traditional support vector machine type method, such as kernel function limitation, parameter tuning complexity, and etc. Due to the advantages of RVM, a practical application of this method is made for soft sensor modeling in this paper. To evaluate the performance of the developed soft sensor, two case studies are demonstrated, which both support that RVM performs much better than other methods for soft sensing. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101146d Exemplaires
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Titre : Multiblock-based qualitative and quantitative spectral calibration analysis Type de document : texte imprimé Auteurs : Chunhui Zhao, Auteur ; Furong Gao, Auteur Année de publication : 2010 Article en page(s) : pp. 8694–8704 Note générale : Industrial chemistry Langues : Anglais (eng) Résumé : In this article, an improved spectral calibration and statistical analysis approach is proposed. Having realized the multiplicity of underlying spectral characteristics and their different effects on the quality of interpretation and prediction, the major task lies in how to qualify and quantify the descriptor−quality relationship more meaningfully over different wavelength subspaces. The underlying spectral information can be explored more comprehensively by a spectral subspace separation and multiblock modeling strategy. Unlike the specific purpose of quality predictions over different spectral subspaces, systematic information in both descriptor and quality spaces is decomposed into different parts under the control of different between-set relationships. Closely related variations and irrelevant ones are discriminated and evaluated separately, where, in particular, the orthogonal variations, as important systematic information, are quantified in specific model parameters, even though they are not predictive. In this way, the approach well tracks the wavelength-varying underlying characteristics, takes full advantage of underlying variations in both X and Y spaces, and allows for a more meaningful interpretation of the between-set relationship. This article theoretically and experimentally illustrates the efficiency of the proposed method in qualitative and quantitative spectral calibration analysis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100892y
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8694–8704[article] Multiblock-based qualitative and quantitative spectral calibration analysis [texte imprimé] / Chunhui Zhao, Auteur ; Furong Gao, Auteur . - 2010 . - pp. 8694–8704.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8694–8704
Résumé : In this article, an improved spectral calibration and statistical analysis approach is proposed. Having realized the multiplicity of underlying spectral characteristics and their different effects on the quality of interpretation and prediction, the major task lies in how to qualify and quantify the descriptor−quality relationship more meaningfully over different wavelength subspaces. The underlying spectral information can be explored more comprehensively by a spectral subspace separation and multiblock modeling strategy. Unlike the specific purpose of quality predictions over different spectral subspaces, systematic information in both descriptor and quality spaces is decomposed into different parts under the control of different between-set relationships. Closely related variations and irrelevant ones are discriminated and evaluated separately, where, in particular, the orthogonal variations, as important systematic information, are quantified in specific model parameters, even though they are not predictive. In this way, the approach well tracks the wavelength-varying underlying characteristics, takes full advantage of underlying variations in both X and Y spaces, and allows for a more meaningful interpretation of the between-set relationship. This article theoretically and experimentally illustrates the efficiency of the proposed method in qualitative and quantitative spectral calibration analysis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100892y Exemplaires
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Titre : COSMO-RS-based screening of ionic liquids as green solvents in denitrification studies Type de document : texte imprimé Auteurs : R. Anantharaj, Auteur ; Tamal Banerjee, Auteur Année de publication : 2010 Article en page(s) : pp. 8705–8725 Note générale : Industrial chemistry
Langues : Anglais (eng) Mots-clés : Ionic liquids Résumé : Five- and six-membered heteroaromatic nitrogen compounds play an inhibiting role in the hydrodesulfurization of diesel oil. In this work, the ionic liquids (ILs) are used as green solvents to remove such compounds by liquid−liquid extraction (LLE). Approximately 168 ILs comprising cations which include 1-ethyl-3-methylimidaozlium [EMIM], 1-ethylpyridinium [EPY], 1-ethyl-1-methyl pyrrolidinium [EPYRO], 1-ethyl-1-methylpiperidinium [EMPIP], 4-ethyl-4-methyl morpholinium [EMMOR], and 1,2,4-trimethylpyrazolium[TMPYZO] combined with 26 anions were investigated in this work. The infinite dilution activity coefficient (IDAC) was predicted through the conductor-like screening model for real solvents (COSMO-RS) model in order to screen the potential solvents. Initially the model was benchmarked via IDAC and LLE predictions. LLE was predicted for four reported ternary systems in which a nitrogen heterocycle was one of the compounds. The average root-mean-square deviation (rmsd) obtained was 10%. The IDAC values were predicted for pyridine in two ionic liquids, namely [BMIM][BF4] and [EMIM][TOS], with a root-mean-square (rms) error of 8%. Thereafter the selectivity, capacity, and performance index at infinite dilution were calculated to evaluate the performance. It was found that the five-membered nitrogen species having high delocalized electron density possessed 3 orders of magnitude higher selectivity than the six-membered nitrogen species. For the five-membered ring structures, the selectivity was found to follow the order [EPYRO] > [EMPIP] > [EPY] > [EMMOR] > [EMIM] > [TMPYZO]. For the six-membered heterocycle, it followed the order [EPY] > [EMMOR] > [EPYRO] > [EMPIP] > [EMIM] > [TMPYZO]. Irrespective of nitrogen heterocycle, anions such as thiocyanate [SCN] and acetate [Ac] gave high values of selectivity. In general cations without aromatic rings such as [EPYRO], [EMPIP], and [EMMOR] gave higher selectivity and capacity irrespective of the nitrogen heterocycle. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901341k
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8705–8725[article] COSMO-RS-based screening of ionic liquids as green solvents in denitrification studies [texte imprimé] / R. Anantharaj, Auteur ; Tamal Banerjee, Auteur . - 2010 . - pp. 8705–8725.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8705–8725
Mots-clés : Ionic liquids Résumé : Five- and six-membered heteroaromatic nitrogen compounds play an inhibiting role in the hydrodesulfurization of diesel oil. In this work, the ionic liquids (ILs) are used as green solvents to remove such compounds by liquid−liquid extraction (LLE). Approximately 168 ILs comprising cations which include 1-ethyl-3-methylimidaozlium [EMIM], 1-ethylpyridinium [EPY], 1-ethyl-1-methyl pyrrolidinium [EPYRO], 1-ethyl-1-methylpiperidinium [EMPIP], 4-ethyl-4-methyl morpholinium [EMMOR], and 1,2,4-trimethylpyrazolium[TMPYZO] combined with 26 anions were investigated in this work. The infinite dilution activity coefficient (IDAC) was predicted through the conductor-like screening model for real solvents (COSMO-RS) model in order to screen the potential solvents. Initially the model was benchmarked via IDAC and LLE predictions. LLE was predicted for four reported ternary systems in which a nitrogen heterocycle was one of the compounds. The average root-mean-square deviation (rmsd) obtained was 10%. The IDAC values were predicted for pyridine in two ionic liquids, namely [BMIM][BF4] and [EMIM][TOS], with a root-mean-square (rms) error of 8%. Thereafter the selectivity, capacity, and performance index at infinite dilution were calculated to evaluate the performance. It was found that the five-membered nitrogen species having high delocalized electron density possessed 3 orders of magnitude higher selectivity than the six-membered nitrogen species. For the five-membered ring structures, the selectivity was found to follow the order [EPYRO] > [EMPIP] > [EPY] > [EMMOR] > [EMIM] > [TMPYZO]. For the six-membered heterocycle, it followed the order [EPY] > [EMMOR] > [EPYRO] > [EMPIP] > [EMIM] > [TMPYZO]. Irrespective of nitrogen heterocycle, anions such as thiocyanate [SCN] and acetate [Ac] gave high values of selectivity. In general cations without aromatic rings such as [EPYRO], [EMPIP], and [EMMOR] gave higher selectivity and capacity irrespective of the nitrogen heterocycle. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901341k Exemplaires
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Titre : Uptake of bromate ion on amorphous aluminum hydroxide Type de document : texte imprimé Auteurs : Ramesh Chitrakar, Auteur ; Keisuke Mizobuchi, Auteur ; Akinari Sonoda, Auteur Année de publication : 2010 Article en page(s) : pp. 8726–8732 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Uptake aqueous solutions Hydroxide Résumé : Batch experiments were performed to examine the BrO3− uptake from dilute aqueous solutions on amorphous aluminum hydroxide (Cl− type), which was synthesized by addition of a 3 mol/dm3 NaOH solution to a 0.1 mol/dm3 AlCl3 solution until the pH reached 5.8. The uptake from a 0.78 μmol/dm3 BrO3− solution (100 μg of BrO3/dm3) was rapid: equilibrium was attained within 3 min. The BrO3− uptake was found to decrease slowly at pH 4−8 and rapidly at pH >8. The isotherm for BrO3− uptake was well fitted with the Freundlich isotherm model. From distribution coefficient (Kd) values determined from mixed solutions containing 0.10, 1.0, and 2.0 mmol/dm3 NaCl, NaBrO3, NaNO3, Na2SO4, and Na2CO3, the selectivity order was reported as NO3− ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901705n
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8726–8732[article] Uptake of bromate ion on amorphous aluminum hydroxide [texte imprimé] / Ramesh Chitrakar, Auteur ; Keisuke Mizobuchi, Auteur ; Akinari Sonoda, Auteur . - 2010 . - pp. 8726–8732.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8726–8732
Mots-clés : Uptake aqueous solutions Hydroxide Résumé : Batch experiments were performed to examine the BrO3− uptake from dilute aqueous solutions on amorphous aluminum hydroxide (Cl− type), which was synthesized by addition of a 3 mol/dm3 NaOH solution to a 0.1 mol/dm3 AlCl3 solution until the pH reached 5.8. The uptake from a 0.78 μmol/dm3 BrO3− solution (100 μg of BrO3/dm3) was rapid: equilibrium was attained within 3 min. The BrO3− uptake was found to decrease slowly at pH 4−8 and rapidly at pH >8. The isotherm for BrO3− uptake was well fitted with the Freundlich isotherm model. From distribution coefficient (Kd) values determined from mixed solutions containing 0.10, 1.0, and 2.0 mmol/dm3 NaCl, NaBrO3, NaNO3, Na2SO4, and Na2CO3, the selectivity order was reported as NO3− ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901705n Exemplaires
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Titre : Recovery of ethanol from carbon dioxide stripped vapor mixture : adsorption prediction and modeling Type de document : texte imprimé Auteurs : M. Hashi, Auteur ; J. Thibault, Auteur ; F. H. Tezel, Auteur Année de publication : 2010 Article en page(s) : pp. 8733–8740 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon Dioxide Adsorption Résumé : Carbon dioxide stripping of ethanol and adsorption can be used in a bioethanol fermentation system to reduce product inhibition. To gain a better understanding of the bioethanol adsorption process, a mathematical model was used to predict the adsorption performance of activated carbon WV-B 1500 for ethanol vapor adsorption in the presence of carbon dioxide and water. The model takes into account changes in velocity due to adsorption, heat effects during adsorption, and heat losses to the surroundings. The model, developed without resorting to fitting parameters, was validated successfully by comparing the model predictions with experimental adsorption data. Finally, the model was used to predict the adsorption working capacities to assess the performance of the adsorption process in an industrial process. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002608
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8733–8740[article] Recovery of ethanol from carbon dioxide stripped vapor mixture : adsorption prediction and modeling [texte imprimé] / M. Hashi, Auteur ; J. Thibault, Auteur ; F. H. Tezel, Auteur . - 2010 . - pp. 8733–8740.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8733–8740
Mots-clés : Carbon Dioxide Adsorption Résumé : Carbon dioxide stripping of ethanol and adsorption can be used in a bioethanol fermentation system to reduce product inhibition. To gain a better understanding of the bioethanol adsorption process, a mathematical model was used to predict the adsorption performance of activated carbon WV-B 1500 for ethanol vapor adsorption in the presence of carbon dioxide and water. The model takes into account changes in velocity due to adsorption, heat effects during adsorption, and heat losses to the surroundings. The model, developed without resorting to fitting parameters, was validated successfully by comparing the model predictions with experimental adsorption data. Finally, the model was used to predict the adsorption working capacities to assess the performance of the adsorption process in an industrial process. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002608 Exemplaires
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Titre : Bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO)-based amphoteric hollow-fiber membranes : preparation and lysozyme adsorption Type de document : texte imprimé Auteurs : Zhenfeng Cheng, Auteur ; Cuiming Wu, Auteur ; Weihua Yang, Auteur Année de publication : 2010 Article en page(s) : pp. 8741–8748 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hollow-fiber membrane Résumé : For the recovery and purification of proteins, an amphoteric hollow-fiber membrane (AHFM) was prepared from bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) by ethylenediamination and carboxylation. The success in modifying BPPO was confirmed by FTIR spectra, amphoteric group density, anion-exchange capacity (AEC), and cation-exchange capacity (CEC). For potential applications, the membranes were tested for the adsorption of lysozyme, and the results showed that the adsorption amount increased with increasing initial lysozyme concentration. The adsorption fits the Langmuir isotherm and the Freundlich equation well, and the maximum experimental amount of lysozyme adsorbed was found to be 4.00 mg/g, which was close to the calculated values (3.85 and 4.13 mg/g according to the Langmuir and Freundlich equations, respectively). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100348e
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8741–8748[article] Bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO)-based amphoteric hollow-fiber membranes : preparation and lysozyme adsorption [texte imprimé] / Zhenfeng Cheng, Auteur ; Cuiming Wu, Auteur ; Weihua Yang, Auteur . - 2010 . - pp. 8741–8748.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8741–8748
Mots-clés : Hollow-fiber membrane Résumé : For the recovery and purification of proteins, an amphoteric hollow-fiber membrane (AHFM) was prepared from bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) by ethylenediamination and carboxylation. The success in modifying BPPO was confirmed by FTIR spectra, amphoteric group density, anion-exchange capacity (AEC), and cation-exchange capacity (CEC). For potential applications, the membranes were tested for the adsorption of lysozyme, and the results showed that the adsorption amount increased with increasing initial lysozyme concentration. The adsorption fits the Langmuir isotherm and the Freundlich equation well, and the maximum experimental amount of lysozyme adsorbed was found to be 4.00 mg/g, which was close to the calculated values (3.85 and 4.13 mg/g according to the Langmuir and Freundlich equations, respectively). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100348e Exemplaires
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Titre : Absorption and oxidation of nitric oxide (NO) by aqueous solutions of sodium persulfate in a bubble column reactor Type de document : texte imprimé Auteurs : Nymul E. Khan, Auteur ; Yusuf G. Adewuyi, Auteur Année de publication : 2010 Article en page(s) : pp. 8749–8760 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Aqueous Solutions Bubble column Résumé : The absorption−oxidation of nitric oxide (NO) by aqueous solution of sodium persulfate (Na2S2O8) has been studied in a bubble column reactor operated in semibatch mode. The effects of different process variables such as the persulfate concentration (0.01−0.2 M), temperature (23−90 °C), pH (4−12), sodium chloride concentration (0−0.5 M), and NO concentration (500−1000 ppm) were studied. In general, the NO fractional conversion (percent of inlet NO removed) at all temperatures increased almost linearly with persulfate concentration up to about 0.1 M, after which it started to level off. Increased temperature led to an increased fractional conversion of NO at all persulfate levels. At 0.1 M persulfate concentration, conversions of up to 69% and 92% were observed at 70 and 90 °C, respectively. Solution pH and chloride concentration were both found to affect NO absorption at higher temperatures. The effect of pH was moderate, but sodium chloride showed a significant effect on NO absorption at 70 °C, to the point of causing complete removal of NO. The effect of initial NO concentration in the gas phase was found to be marginal. The results demonstrate the feasibility of NO removal using aqueous solutions of sodium persulfate. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100607u
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8749–8760[article] Absorption and oxidation of nitric oxide (NO) by aqueous solutions of sodium persulfate in a bubble column reactor [texte imprimé] / Nymul E. Khan, Auteur ; Yusuf G. Adewuyi, Auteur . - 2010 . - pp. 8749–8760.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8749–8760
Mots-clés : Aqueous Solutions Bubble column Résumé : The absorption−oxidation of nitric oxide (NO) by aqueous solution of sodium persulfate (Na2S2O8) has been studied in a bubble column reactor operated in semibatch mode. The effects of different process variables such as the persulfate concentration (0.01−0.2 M), temperature (23−90 °C), pH (4−12), sodium chloride concentration (0−0.5 M), and NO concentration (500−1000 ppm) were studied. In general, the NO fractional conversion (percent of inlet NO removed) at all temperatures increased almost linearly with persulfate concentration up to about 0.1 M, after which it started to level off. Increased temperature led to an increased fractional conversion of NO at all persulfate levels. At 0.1 M persulfate concentration, conversions of up to 69% and 92% were observed at 70 and 90 °C, respectively. Solution pH and chloride concentration were both found to affect NO absorption at higher temperatures. The effect of pH was moderate, but sodium chloride showed a significant effect on NO absorption at 70 °C, to the point of causing complete removal of NO. The effect of initial NO concentration in the gas phase was found to be marginal. The results demonstrate the feasibility of NO removal using aqueous solutions of sodium persulfate. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100607u Exemplaires
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Titre : Formation of cellulose acetate membranes via phase inversion using ionic liquid, [BMIM]SCN, as the solvent Type de document : texte imprimé Auteurs : Ding Yu Xing, Auteur ; Na Peng, Auteur ; Tai-Shung Chung, Auteur Année de publication : 2010 Article en page(s) : pp. 8761–8769 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ionic liquid Résumé : Ionic liquids have gained worldwide attention as green solvents in the past decade. This study explores, for the first time, the fundamental science and engineering of using ionic liquids as a new generation of solvents to replace traditional organic solvents for the fabrication of flat sheet membranes and hollow fiber membranes. The fundamentals and characteristics of membrane formation of cellulose acetate (CA) membranes have been investigated using 1-butyl-3-methylimidazolium thiocyanate ([BMIM]SCN) as the solvent via phase inversion in water. For elucidation, other solvents, i.e., N-methyl-2-pyrrolidinone (NMP) and acetone, were also studied. It is found that [BMIM]SCN has distinctive effects on phase inversion process and membrane morphology compared to NMP and acetone because of its unique nature of high viscosity and the high ratio of [BMIM]SCN outflow to water inflow. Membranes cast or spun from CA/[BMIM]SCN have a macrovoid-free dense structure full of nodules, implying the paths of phase inversion are mainly nucleation growth and gelation, followed possibly by spinodal decomposition. The recovery and reuse of [BMIM]SCN have also been demonstrated and achieved. The derived flat sheet membranes made from the recovered [BMIM]SCN show morphological and performance characteristics similar to those from the fresh [BMIM]SCN. It is believed that this study could enrich the understanding of membrane formation using environmentally benign ionic liquids. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007085
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8761–8769[article] Formation of cellulose acetate membranes via phase inversion using ionic liquid, [BMIM]SCN, as the solvent [texte imprimé] / Ding Yu Xing, Auteur ; Na Peng, Auteur ; Tai-Shung Chung, Auteur . - 2010 . - pp. 8761–8769.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8761–8769
Mots-clés : Ionic liquid Résumé : Ionic liquids have gained worldwide attention as green solvents in the past decade. This study explores, for the first time, the fundamental science and engineering of using ionic liquids as a new generation of solvents to replace traditional organic solvents for the fabrication of flat sheet membranes and hollow fiber membranes. The fundamentals and characteristics of membrane formation of cellulose acetate (CA) membranes have been investigated using 1-butyl-3-methylimidazolium thiocyanate ([BMIM]SCN) as the solvent via phase inversion in water. For elucidation, other solvents, i.e., N-methyl-2-pyrrolidinone (NMP) and acetone, were also studied. It is found that [BMIM]SCN has distinctive effects on phase inversion process and membrane morphology compared to NMP and acetone because of its unique nature of high viscosity and the high ratio of [BMIM]SCN outflow to water inflow. Membranes cast or spun from CA/[BMIM]SCN have a macrovoid-free dense structure full of nodules, implying the paths of phase inversion are mainly nucleation growth and gelation, followed possibly by spinodal decomposition. The recovery and reuse of [BMIM]SCN have also been demonstrated and achieved. The derived flat sheet membranes made from the recovered [BMIM]SCN show morphological and performance characteristics similar to those from the fresh [BMIM]SCN. It is believed that this study could enrich the understanding of membrane formation using environmentally benign ionic liquids. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007085 Exemplaires
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Titre : Characteristics of the marangoni convection induced in initial quiescent water Type de document : texte imprimé Auteurs : Yong Sha, Auteur ; Hongling Chen, Auteur ; Yingwu Yin, Auteur Année de publication : 2010 Article en page(s) : pp. 8770–8777 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Marangoni convection Résumé : By means of continuous deposition of the surface tension-lowering solvent at the quiescent water surface, the closed-loop Marangoni convection can be induced as a single convection cell at the air−water interface. For this single Marangoni convection cell, its temporal-spatial evolution is visualized by means of the shadowgraph optical method, and its surface radial velocity distribution is measured with the help of the high speed photography technique. Meanwhile, an absorption experiment of CO2 into water, a scaling analysis, and a 2-D numerical simulation are conducted, respectively, to investigate mass transfer performance and flow characteristics of the induced Marangoni convection. Results show that the induced Marangoni convection has the high surface velocity, the sharp velocity gradient is in the immediate vicinity of the water surface, and the velocity of the Marangoni convection in the bulk of water is much less than that near the interface. The high surface velocity of the Marangoni convection along with its closed-loop flow structure impels exchange of the solvent between the interfacial neighborhood and the bulk of liquid and enhances renewal of the interfacial fluid. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007163?journalCode=iecred
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8770–8777[article] Characteristics of the marangoni convection induced in initial quiescent water [texte imprimé] / Yong Sha, Auteur ; Hongling Chen, Auteur ; Yingwu Yin, Auteur . - 2010 . - pp. 8770–8777.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8770–8777
Mots-clés : Marangoni convection Résumé : By means of continuous deposition of the surface tension-lowering solvent at the quiescent water surface, the closed-loop Marangoni convection can be induced as a single convection cell at the air−water interface. For this single Marangoni convection cell, its temporal-spatial evolution is visualized by means of the shadowgraph optical method, and its surface radial velocity distribution is measured with the help of the high speed photography technique. Meanwhile, an absorption experiment of CO2 into water, a scaling analysis, and a 2-D numerical simulation are conducted, respectively, to investigate mass transfer performance and flow characteristics of the induced Marangoni convection. Results show that the induced Marangoni convection has the high surface velocity, the sharp velocity gradient is in the immediate vicinity of the water surface, and the velocity of the Marangoni convection in the bulk of water is much less than that near the interface. The high surface velocity of the Marangoni convection along with its closed-loop flow structure impels exchange of the solvent between the interfacial neighborhood and the bulk of liquid and enhances renewal of the interfacial fluid. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007163?journalCode=iecred Exemplaires
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Titre : Polyimide/polyethersulfone dual-layer hollow fiber membranes for hydrogen enrichment Type de document : texte imprimé Auteurs : Bee Ting Low, Auteur ; Natalia Widjojo, Auteur ; Tai-Shung Chung, Auteur Année de publication : 2010 Article en page(s) : pp. 8778–8786 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hollow fiber membranes Résumé : We have developed functional poly(1,5-naphthalene-2,2′-bis(3,4-phthalic)hexafluoropropane diimide (6FDA-NDA)/polyethersulfone (PES) dual layer hollow fiber membranes and studied the H2/CO2 separation performance with and without 1,3-diaminopropane (PDA) modification. The effects of air gap on the membrane gas transport properties are investigated and it is observed that the optimal air gap for maximizing the ideal permselectivity is strongly dependent on the kinetic diameters of gas pair molecules. A higher air gap diminishes the population of Knudsen pores in the apparently dense outer skin and induces greater elongational stresses on polymer chains. The latter enhances polymer chain alignment and packing which possibly results in the shift and sharpening of the free volume distribution. The diamine modification of 6FDA-NDA/PES dual layer hollow fiber membranes effectively enhances the H2/CO2 permselectivity and suppresses the CO2-induced plasticization. At higher temperatures, the H2 permeance of the PDA-modified fibers increases with negligible decrease in the H2/CO2 permselectivity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008986
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8778–8786[article] Polyimide/polyethersulfone dual-layer hollow fiber membranes for hydrogen enrichment [texte imprimé] / Bee Ting Low, Auteur ; Natalia Widjojo, Auteur ; Tai-Shung Chung, Auteur . - 2010 . - pp. 8778–8786.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8778–8786
Mots-clés : Hollow fiber membranes Résumé : We have developed functional poly(1,5-naphthalene-2,2′-bis(3,4-phthalic)hexafluoropropane diimide (6FDA-NDA)/polyethersulfone (PES) dual layer hollow fiber membranes and studied the H2/CO2 separation performance with and without 1,3-diaminopropane (PDA) modification. The effects of air gap on the membrane gas transport properties are investigated and it is observed that the optimal air gap for maximizing the ideal permselectivity is strongly dependent on the kinetic diameters of gas pair molecules. A higher air gap diminishes the population of Knudsen pores in the apparently dense outer skin and induces greater elongational stresses on polymer chains. The latter enhances polymer chain alignment and packing which possibly results in the shift and sharpening of the free volume distribution. The diamine modification of 6FDA-NDA/PES dual layer hollow fiber membranes effectively enhances the H2/CO2 permselectivity and suppresses the CO2-induced plasticization. At higher temperatures, the H2 permeance of the PDA-modified fibers increases with negligible decrease in the H2/CO2 permselectivity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008986 Exemplaires
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Titre : Computational study on purification of CO2 from natural gas by C60 intercalated graphite Type de document : texte imprimé Auteurs : Xuan Peng, Auteur ; Dapeng Cao, Auteur ; Wenchuan Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 8787–8796 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Natural Gas Résumé : By combining grand canonical Monte Carlo (GCMC) simulations with adsorption theory, we perform a computational study on adsorption of CH4 and CO2 gases and purification of CO2 from the CH4−CO2 and N2−CO2 binary mixtures by the C60 intercalated graphite. The adsorption isotherms, isosteric heats and snapshots of pure gases have been examined extensively. It is found that the maximum excess uptakes at 298 K are relatively low, only giving 4.04 and 4.96 mmol/g for CH4 and CO2, respectively, due to a low porosity of 0.45 and a large crystal density of 1.57 g/cm3 of this material. It indicates that the pristine material is not suitable for gas storage. However, this material provides excellent selectivity for CO2, and the selectivity at ambient condition can reach 8 and 50 for the CH4−CO2 and N2−CO2 mixture, respectively. Furthermore, the selectivity of CO2 is almost independent of the bulk gas composition for P > 0.1 MPa. The dual-site Langmuir−Freundlich (DSLF) equation is used to fit the adsorption isotherms of pure gases from GCMC simulations, and the corresponding parameters are obtained. Moreover, we further predicted the adsorption behavior of binary mixtures by the DSLF-based ideal adsorption solution theory (IAST). Although the IAST theory slightly overestimates the selectivity, compared to GCMC results, the uptakes and selectivity from both methods are basically consistent. To improve the adsorption capacities, we further tailor the structural parameter “g” of the C60 intercalated graphite by GCMC simulations. For equimolar gas composition, at the condition of g = 1.4 nm and 6 MPa, the CO2 uptakes could be raised by 200%, approaching 12 mmol/g for both mixtures, without loss of the selectivity for CO2. In summary, this work demonstrates that the C60 intercalated graphite is an excellent material for CO2 purification, especially for N2−CO2 system at room temperature. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010433
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8787–8796[article] Computational study on purification of CO2 from natural gas by C60 intercalated graphite [texte imprimé] / Xuan Peng, Auteur ; Dapeng Cao, Auteur ; Wenchuan Wang, Auteur . - 2010 . - pp. 8787–8796.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8787–8796
Mots-clés : Natural Gas Résumé : By combining grand canonical Monte Carlo (GCMC) simulations with adsorption theory, we perform a computational study on adsorption of CH4 and CO2 gases and purification of CO2 from the CH4−CO2 and N2−CO2 binary mixtures by the C60 intercalated graphite. The adsorption isotherms, isosteric heats and snapshots of pure gases have been examined extensively. It is found that the maximum excess uptakes at 298 K are relatively low, only giving 4.04 and 4.96 mmol/g for CH4 and CO2, respectively, due to a low porosity of 0.45 and a large crystal density of 1.57 g/cm3 of this material. It indicates that the pristine material is not suitable for gas storage. However, this material provides excellent selectivity for CO2, and the selectivity at ambient condition can reach 8 and 50 for the CH4−CO2 and N2−CO2 mixture, respectively. Furthermore, the selectivity of CO2 is almost independent of the bulk gas composition for P > 0.1 MPa. The dual-site Langmuir−Freundlich (DSLF) equation is used to fit the adsorption isotherms of pure gases from GCMC simulations, and the corresponding parameters are obtained. Moreover, we further predicted the adsorption behavior of binary mixtures by the DSLF-based ideal adsorption solution theory (IAST). Although the IAST theory slightly overestimates the selectivity, compared to GCMC results, the uptakes and selectivity from both methods are basically consistent. To improve the adsorption capacities, we further tailor the structural parameter “g” of the C60 intercalated graphite by GCMC simulations. For equimolar gas composition, at the condition of g = 1.4 nm and 6 MPa, the CO2 uptakes could be raised by 200%, approaching 12 mmol/g for both mixtures, without loss of the selectivity for CO2. In summary, this work demonstrates that the C60 intercalated graphite is an excellent material for CO2 purification, especially for N2−CO2 system at room temperature. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010433 Exemplaires
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Titre : Influence of Incubation Time on the Physicochemical Properties of the isolated hemicelluloses from steam-exploded lespedeza stalks Type de document : texte imprimé Auteurs : Kun Wang, Auteur ; Feng Xu, Auteur ; Run-Cang Sun, Auteur Année de publication : 2010 Article en page(s) : pp. 8797–8804 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Physicochemical properties Résumé : Hemicellulosic polysaccharides were isolated from the raw and steam-exploded Lespedeza crytobytrya stalks by sequential 1 M NaOH extraction and fractionated into Hemi-a and Hemi-b fractions by acidification and ethanol precipitation, respectively. The Hemi-a fractions had relatively lower molecular weights and took up 84.6−95.5% of the total released hemicelluloses. After steam explosion, both hemicellulosic fractions were obviously degraded, and a certain amount of glucose or oligosaccharides derived from the amorphous cellulose was coisolated. The influence of increasing incubation time from 2 to 10 min is further discussed, based on the physicochemical properties of the obtained hemicelluloses characterized in terms of sugar component, gel permeation chromatography (GPC), thermal stability, and 13C NMR spectroscopy analysis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101180p
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8797–8804[article] Influence of Incubation Time on the Physicochemical Properties of the isolated hemicelluloses from steam-exploded lespedeza stalks [texte imprimé] / Kun Wang, Auteur ; Feng Xu, Auteur ; Run-Cang Sun, Auteur . - 2010 . - pp. 8797–8804.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8797–8804
Mots-clés : Physicochemical properties Résumé : Hemicellulosic polysaccharides were isolated from the raw and steam-exploded Lespedeza crytobytrya stalks by sequential 1 M NaOH extraction and fractionated into Hemi-a and Hemi-b fractions by acidification and ethanol precipitation, respectively. The Hemi-a fractions had relatively lower molecular weights and took up 84.6−95.5% of the total released hemicelluloses. After steam explosion, both hemicellulosic fractions were obviously degraded, and a certain amount of glucose or oligosaccharides derived from the amorphous cellulose was coisolated. The influence of increasing incubation time from 2 to 10 min is further discussed, based on the physicochemical properties of the obtained hemicelluloses characterized in terms of sugar component, gel permeation chromatography (GPC), thermal stability, and 13C NMR spectroscopy analysis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101180p Exemplaires
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Titre : Comparison between electrical capacitance tomography and wire mesh sensor output for air/silicone oil flow in a vertical pipe Type de document : texte imprimé Auteurs : B. J. Azzopardi, Auteur ; L. A. Abdulkareem, Auteur ; D. Zhao, Auteur Année de publication : 2010 Article en page(s) : pp. 8805–8811 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Tomographic techniques Résumé : Two tomographic techniques have been applied simultaneously to the flow of air and silicone oil in 67 mm internal diameter vertical pipe. A twin plane electrical capacitance tomgraphy (ECT) electrode system driven by Tomoflow electronics was positioned below a new capacitance wire mesh sensor (WMS) system. The former used 8 electrodes around the pipe in each plane, the latter employed two arrays of 24 evenly spaced wires stretched over the pipe cross-section. The ECT measurement was triggered from the WMS electronics. High speed videos were also taken simultaneously through the transparent pipe wall. Gas superficial velocities of 0.05−5.5 m/s and liquid superficial velocities of 0−0.7 m/s were studied. These gave bubbly, slug, and churn flow in the pipe. The outputs of the two techniques have been compared at a number of levels. At its most basic, the time averaged cross-sectionally averaged void fractions were compared. They showed excellent agreement. At the next level, the time series of the cross-sectionally averaged void fraction were considered directly and through their variations in amplitude and frequency space. Examples of probability density functions are presented. Radial variations of the void fraction were also considered. Thereafter the shapes of the large bubbles and the velocities of periodic structures are presented. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901949z
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8805–8811[article] Comparison between electrical capacitance tomography and wire mesh sensor output for air/silicone oil flow in a vertical pipe [texte imprimé] / B. J. Azzopardi, Auteur ; L. A. Abdulkareem, Auteur ; D. Zhao, Auteur . - 2010 . - pp. 8805–8811.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8805–8811
Mots-clés : Tomographic techniques Résumé : Two tomographic techniques have been applied simultaneously to the flow of air and silicone oil in 67 mm internal diameter vertical pipe. A twin plane electrical capacitance tomgraphy (ECT) electrode system driven by Tomoflow electronics was positioned below a new capacitance wire mesh sensor (WMS) system. The former used 8 electrodes around the pipe in each plane, the latter employed two arrays of 24 evenly spaced wires stretched over the pipe cross-section. The ECT measurement was triggered from the WMS electronics. High speed videos were also taken simultaneously through the transparent pipe wall. Gas superficial velocities of 0.05−5.5 m/s and liquid superficial velocities of 0−0.7 m/s were studied. These gave bubbly, slug, and churn flow in the pipe. The outputs of the two techniques have been compared at a number of levels. At its most basic, the time averaged cross-sectionally averaged void fractions were compared. They showed excellent agreement. At the next level, the time series of the cross-sectionally averaged void fraction were considered directly and through their variations in amplitude and frequency space. Examples of probability density functions are presented. Radial variations of the void fraction were also considered. Thereafter the shapes of the large bubbles and the velocities of periodic structures are presented. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901949z Exemplaires
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Titre : Kinetics and reductive degradation of surfactant-solublized CCl4 in water using bimetallic particles Type de document : texte imprimé Auteurs : S. Harendra, Auteur ; C. Vipulanandan, Auteur Année de publication : 2010 Article en page(s) : pp. 8812–8820 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics Bimetallic particles Résumé : Degradation of high concentrations of carbon tetrachloride (CCl4) solubilized using surfactants were investigated in this study. Iron−nickel particles have been studied as a reagent for the dehalogenation of CCl4. Surfactants such as anionic (sodium dodecyl sulfate (SDS)), nonionic (Triton X-100), cationic (cetyltrimethylammonium bromide (CTAB)) Rhaminolipid, and a biosurfactant (UH—biosurfactant) were used in solubilization studies at room temperature in continuously stirred batch reactors. The solubility of CCl4 (800 mg/L in water) in the surfactant solutions increased with increase in surfactant concentrations. Of the surfactants studied, Triton X-100 had the highest CCl4 solubilized per gram of surfactant. Bimetallic iron−nickel (Fe−Ni) particles were used in continuously stirred batch reactors for degradation study. The bimetallic particles were synthesized using the solution method and the particles were characterized using the SEM, EDS, and XRD. The CCl4 solubilized up to 8000 mg/L (around 10 times the water solubility) in all surfactant solutions were totally degraded at various rates by 200 g/L of bimetallic Fe−Ni particles in less than 60 h, which is the highest concentration of CCl4 degraded in the shortest time compared to data in the literature. The degradations of CCl4 solubilized in surfactants were represented by nonlinear kinetic relationships which were dependent on the type of surfactant used for solubilizing the CCl4. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001372
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8812–8820[article] Kinetics and reductive degradation of surfactant-solublized CCl4 in water using bimetallic particles [texte imprimé] / S. Harendra, Auteur ; C. Vipulanandan, Auteur . - 2010 . - pp. 8812–8820.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8812–8820
Mots-clés : Kinetics Bimetallic particles Résumé : Degradation of high concentrations of carbon tetrachloride (CCl4) solubilized using surfactants were investigated in this study. Iron−nickel particles have been studied as a reagent for the dehalogenation of CCl4. Surfactants such as anionic (sodium dodecyl sulfate (SDS)), nonionic (Triton X-100), cationic (cetyltrimethylammonium bromide (CTAB)) Rhaminolipid, and a biosurfactant (UH—biosurfactant) were used in solubilization studies at room temperature in continuously stirred batch reactors. The solubility of CCl4 (800 mg/L in water) in the surfactant solutions increased with increase in surfactant concentrations. Of the surfactants studied, Triton X-100 had the highest CCl4 solubilized per gram of surfactant. Bimetallic iron−nickel (Fe−Ni) particles were used in continuously stirred batch reactors for degradation study. The bimetallic particles were synthesized using the solution method and the particles were characterized using the SEM, EDS, and XRD. The CCl4 solubilized up to 8000 mg/L (around 10 times the water solubility) in all surfactant solutions were totally degraded at various rates by 200 g/L of bimetallic Fe−Ni particles in less than 60 h, which is the highest concentration of CCl4 degraded in the shortest time compared to data in the literature. The degradations of CCl4 solubilized in surfactants were represented by nonlinear kinetic relationships which were dependent on the type of surfactant used for solubilizing the CCl4. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001372 Exemplaires
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Titre : Analysis of SO2 removal and ammonium sulfate particle growth in dielectric barrier discharge − photocatalyst hybrid process Type de document : texte imprimé Auteurs : Anna Nasonova, Auteur ; Dong-Joo Kim, Auteur ; Kyo-Seon Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 8821–8825 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Photocatalyst Hybrid process Résumé : We analyzed SO2 removal and ammonium sulfate particle growth in the dielectric barrier discharge−photocatalyst hybrid (DBD−PH) process. The DBD−PH reactor consists of two zones: the first for plasma generation and SO2 conversion and the second for ammonium sulfate particle formation and growth. In this work, the first zone was packed with TiO2-coated glass beads used as a dielectric material. The UV light generated from the plasma discharge activates the TiO2 photocatalyst, and the SO2 removal efficiency increases as a result of the reactive radicals generated by plasma reactions and TiO2 photocatalyst. In this work, the SO2 removal efficiency was found to increase as the applied peak voltage, residence time, and pulsed frequency increased and as the initial SO2 concentration decreased. In the DBD−PH process, gaseous SO2 is converted into H2SO4 and, upon addition of NH3, into solid (NH4)2SO4 particles, which can be separated by particle collectors. Using the second zone of the reactor, we examined (NH4)2SO4 particle growth as a function of reactor length for various process conditions. We found that the (NH4)2SO4 particles grow by particle coagulation and surface reaction along the reactor and that larger particles are produced as the residence time or initial SO2 concentration increases. This study can be a basis for the design of more efficient particle collectors in the DBD−PH process for SO2 and NO removal. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100567v
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8821–8825[article] Analysis of SO2 removal and ammonium sulfate particle growth in dielectric barrier discharge − photocatalyst hybrid process [texte imprimé] / Anna Nasonova, Auteur ; Dong-Joo Kim, Auteur ; Kyo-Seon Kim, Auteur . - 2010 . - pp. 8821–8825.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8821–8825
Mots-clés : Photocatalyst Hybrid process Résumé : We analyzed SO2 removal and ammonium sulfate particle growth in the dielectric barrier discharge−photocatalyst hybrid (DBD−PH) process. The DBD−PH reactor consists of two zones: the first for plasma generation and SO2 conversion and the second for ammonium sulfate particle formation and growth. In this work, the first zone was packed with TiO2-coated glass beads used as a dielectric material. The UV light generated from the plasma discharge activates the TiO2 photocatalyst, and the SO2 removal efficiency increases as a result of the reactive radicals generated by plasma reactions and TiO2 photocatalyst. In this work, the SO2 removal efficiency was found to increase as the applied peak voltage, residence time, and pulsed frequency increased and as the initial SO2 concentration decreased. In the DBD−PH process, gaseous SO2 is converted into H2SO4 and, upon addition of NH3, into solid (NH4)2SO4 particles, which can be separated by particle collectors. Using the second zone of the reactor, we examined (NH4)2SO4 particle growth as a function of reactor length for various process conditions. We found that the (NH4)2SO4 particles grow by particle coagulation and surface reaction along the reactor and that larger particles are produced as the residence time or initial SO2 concentration increases. This study can be a basis for the design of more efficient particle collectors in the DBD−PH process for SO2 and NO removal. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100567v Exemplaires
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Titre : Reactive deposition of palladium nanoparticles onto zeolite membranes in supercritical CO2 Type de document : texte imprimé Auteurs : Xiufeng Liu, Auteur ; Wei Liu, Auteur ; Jian Li, Auteur Année de publication : 2010 Article en page(s) : pp. 8826–8831 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticles Zeolite membranes Résumé : Pd/Si-MFI membranes are fabricated by depositing palladium nanoparticles onto Si-MFI membranes via opposing reactants chemical fluid deposition in supercritical carbon dioxide. Palladium hexafluoroacetylacetonate [Pd(hfac)2] and ethanol are used as the Pd precursor and the reducing agent, respectively, in the deposition process. The resulting Pd/Si-MFI membrane is characterized using SEM, XRD, EPMA, TEM, and EDX techniques. It is demonstrated that a continuous layer of Pd particles with size of 10 nm is covered on the matrix surface while 30-nm Pd particles are plugged into the defects within the matrix. The H2/N2 permselectivity has been significantly increased due to the deposition of Pd nanoparticles in the Si-MFI membrane, which could keep stable below the critical temperature. This bifunctional membrane and similar membranes possess the application potential to achieve various one-step syntheses. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100655m
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8826–8831[article] Reactive deposition of palladium nanoparticles onto zeolite membranes in supercritical CO2 [texte imprimé] / Xiufeng Liu, Auteur ; Wei Liu, Auteur ; Jian Li, Auteur . - 2010 . - pp. 8826–8831.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8826–8831
Mots-clés : Nanoparticles Zeolite membranes Résumé : Pd/Si-MFI membranes are fabricated by depositing palladium nanoparticles onto Si-MFI membranes via opposing reactants chemical fluid deposition in supercritical carbon dioxide. Palladium hexafluoroacetylacetonate [Pd(hfac)2] and ethanol are used as the Pd precursor and the reducing agent, respectively, in the deposition process. The resulting Pd/Si-MFI membrane is characterized using SEM, XRD, EPMA, TEM, and EDX techniques. It is demonstrated that a continuous layer of Pd particles with size of 10 nm is covered on the matrix surface while 30-nm Pd particles are plugged into the defects within the matrix. The H2/N2 permselectivity has been significantly increased due to the deposition of Pd nanoparticles in the Si-MFI membrane, which could keep stable below the critical temperature. This bifunctional membrane and similar membranes possess the application potential to achieve various one-step syntheses. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100655m Exemplaires
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Titre : Micronization of p - aminosalicylic acid particles using high-gravity technique Type de document : texte imprimé Auteurs : Yu-Shao Chen, Auteur ; Yao-Hsuan Wang, Auteur ; Hwai-Shen Liu, Auteur Année de publication : 2010 Article en page(s) : pp. 8832–8840 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Particles High Gravity Technique Résumé : An antisolvent precipitation process was adopted in this study to prepare micrometer-sized p-aminosalicylic acid (PAS) particles using the high-gravity technique. The effects of operating variables on the particle size were investigated. With an increase in the dispersant concentration and disk diameter or a decrease in the drug (PAS) concentration, the particle size of PAS was reduced. In addition, a circular-tube distributor was more effective than a straight-tube distributor for micronization. On the other hand, the effect of the liquid flow rate in the range between 0.25 and 1 L/min was less significant. The high-pressure homogenization following the high-gravity precipitation would effectively reduce the agglomeration of the particles in the suspension to produce drug particles with a mean size of 1 μm. The enhancement of the dissolution rate was significant for the micronized drug particles. The results indicate that the high-gravity process is a promising approach for micronizing drug particles. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007932
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8832–8840[article] Micronization of p - aminosalicylic acid particles using high-gravity technique [texte imprimé] / Yu-Shao Chen, Auteur ; Yao-Hsuan Wang, Auteur ; Hwai-Shen Liu, Auteur . - 2010 . - pp. 8832–8840.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8832–8840
Mots-clés : Particles High Gravity Technique Résumé : An antisolvent precipitation process was adopted in this study to prepare micrometer-sized p-aminosalicylic acid (PAS) particles using the high-gravity technique. The effects of operating variables on the particle size were investigated. With an increase in the dispersant concentration and disk diameter or a decrease in the drug (PAS) concentration, the particle size of PAS was reduced. In addition, a circular-tube distributor was more effective than a straight-tube distributor for micronization. On the other hand, the effect of the liquid flow rate in the range between 0.25 and 1 L/min was less significant. The high-pressure homogenization following the high-gravity precipitation would effectively reduce the agglomeration of the particles in the suspension to produce drug particles with a mean size of 1 μm. The enhancement of the dissolution rate was significant for the micronized drug particles. The results indicate that the high-gravity process is a promising approach for micronizing drug particles. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007932 Exemplaires
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Titre : Continuous hydrothermal synthesis of Fe2O3 nanoparticles using a central collision - type micromixer for rapid and homogeneous nucleation at 673 K and 30 MPa Type de document : texte imprimé Auteurs : Kiwamu Sue, Auteur ; Toshiyuki Sato, Auteur ; Shin-ichiro Kawasaki, Auteur Année de publication : 2010 Article en page(s) : pp. 8841–8846 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticles Micromixer Résumé : Continuous hydrothermal synthesis of Fe2O3 nanoparticles was carried out at 673 K and 30 MPa. Two types of mixers, a conventional T-type micromixer and a central collision-type micromixer (CCM), were used for the synthesis. CCM was newly fabricated on the basis of the concept for preventing heterogeneous nucleation induced on the inner wall of the mixer. Residence time and Fe(NO3)3 molality of the starting solution varied from 0.1 to 1.0 s and 0.05 to 0.50 mol/kg, respectively. Effects of the mixer structure, the residence time, and the Fe(NO3)3 molality on crystal structure, Fe3+ conversion, average particle size, and size distribution were discussed. CCM effectively worked for producing smaller Fe2O3 nanoparticles with narrow and monomodal distribution. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008597
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8841–8846[article] Continuous hydrothermal synthesis of Fe2O3 nanoparticles using a central collision - type micromixer for rapid and homogeneous nucleation at 673 K and 30 MPa [texte imprimé] / Kiwamu Sue, Auteur ; Toshiyuki Sato, Auteur ; Shin-ichiro Kawasaki, Auteur . - 2010 . - pp. 8841–8846.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8841–8846
Mots-clés : Nanoparticles Micromixer Résumé : Continuous hydrothermal synthesis of Fe2O3 nanoparticles was carried out at 673 K and 30 MPa. Two types of mixers, a conventional T-type micromixer and a central collision-type micromixer (CCM), were used for the synthesis. CCM was newly fabricated on the basis of the concept for preventing heterogeneous nucleation induced on the inner wall of the mixer. Residence time and Fe(NO3)3 molality of the starting solution varied from 0.1 to 1.0 s and 0.05 to 0.50 mol/kg, respectively. Effects of the mixer structure, the residence time, and the Fe(NO3)3 molality on crystal structure, Fe3+ conversion, average particle size, and size distribution were discussed. CCM effectively worked for producing smaller Fe2O3 nanoparticles with narrow and monomodal distribution. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008597 Exemplaires
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Titre : Influence of ascorbate and oxalic acid for the removal of iron and alkali from alkali roasted ilmenite to produce synthetic rutile Type de document : texte imprimé Auteurs : Abhishek Lahiri, Auteur Année de publication : 2010 Article en page(s) : pp. 8847–8851 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ascorbic acids Résumé : Leaching of the alkali roasted product was undertaken for the removal of iron and alkali to produce synthetic rutile. The process was carried out in presence of oxalic and ascorbic acids. It was observed that in presence of ascorbic acid the dissolution of iron oxide increased as Fe2+ ions were generated rapidly which then formed ferrous oxalate. Alkali ions were also removed in the process as the pH of the leaching medium was maintained below 4. The production of Fe2+ ions started as early as 30 min whereas the formation of iron oxalate started after 2 hours into the leaching process. In this paper we describe the reaction chemistry in the leaching process by characterizing the samples using Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray techniques. After the leaching process, greater than 95% pure synthetic rutile was achieved. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100893q
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8847–8851[article] Influence of ascorbate and oxalic acid for the removal of iron and alkali from alkali roasted ilmenite to produce synthetic rutile [texte imprimé] / Abhishek Lahiri, Auteur . - 2010 . - pp. 8847–8851.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8847–8851
Mots-clés : Ascorbic acids Résumé : Leaching of the alkali roasted product was undertaken for the removal of iron and alkali to produce synthetic rutile. The process was carried out in presence of oxalic and ascorbic acids. It was observed that in presence of ascorbic acid the dissolution of iron oxide increased as Fe2+ ions were generated rapidly which then formed ferrous oxalate. Alkali ions were also removed in the process as the pH of the leaching medium was maintained below 4. The production of Fe2+ ions started as early as 30 min whereas the formation of iron oxalate started after 2 hours into the leaching process. In this paper we describe the reaction chemistry in the leaching process by characterizing the samples using Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray techniques. After the leaching process, greater than 95% pure synthetic rutile was achieved. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100893q Exemplaires
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Titre : Effect of ionic liquids CnmimBr on properties of gemini surfactant 12 - 3 - 12 aqueous solution Type de document : texte imprimé Auteurs : Yazhuo Shang, Auteur ; Tengfang Wang, Auteur ; Xia Han, Auteur Année de publication : 2010 Article en page(s) : pp. 8852–8857 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ionic liquids Résumé : The effect of ionic liquids CnmimBr (n = 4, 6, 8) on the properties of cationic Gemini surfactant trimethylene-1,3-bis(dodecyl ammonium bromide) (Gemini 12-3-12) aqueous solution was investigated. The critical micelle concentration (cmc) of Gemini 12-3-12 solutions containing different amounts of ionic liquids were obtained by measurement of surface tension. The composition of mixed micelle and the interaction parameter between ionic liquids and Gemini 12-3-12 were calculated by Rubingh regular solution model; the effective area of Gemini 12-3-12 molecule at air/water interface was calculated by Gibbs adsorption isotherm. The results show that the addition of ionic liquid has important effect on the properties of surfactant aqueous solution. The cmc of surfactant solution and the effective area of surfactant molecules at the air/water interface vary parabolically with the addition of ionic liquids owing to the two extra opposite effects of ionic liquids in surfactant aqueous solutions besides counterion effect, participation of micelles formation, and the effect on the properties of solvent. The effect of ionic liquids on surfactant solution can be regarded as the comprehensive effects of inorganic salt, cosurfactant, and cosolvent on surfactant solution. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100896z
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8852–8857[article] Effect of ionic liquids CnmimBr on properties of gemini surfactant 12 - 3 - 12 aqueous solution [texte imprimé] / Yazhuo Shang, Auteur ; Tengfang Wang, Auteur ; Xia Han, Auteur . - 2010 . - pp. 8852–8857.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8852–8857
Mots-clés : Ionic liquids Résumé : The effect of ionic liquids CnmimBr (n = 4, 6, 8) on the properties of cationic Gemini surfactant trimethylene-1,3-bis(dodecyl ammonium bromide) (Gemini 12-3-12) aqueous solution was investigated. The critical micelle concentration (cmc) of Gemini 12-3-12 solutions containing different amounts of ionic liquids were obtained by measurement of surface tension. The composition of mixed micelle and the interaction parameter between ionic liquids and Gemini 12-3-12 were calculated by Rubingh regular solution model; the effective area of Gemini 12-3-12 molecule at air/water interface was calculated by Gibbs adsorption isotherm. The results show that the addition of ionic liquid has important effect on the properties of surfactant aqueous solution. The cmc of surfactant solution and the effective area of surfactant molecules at the air/water interface vary parabolically with the addition of ionic liquids owing to the two extra opposite effects of ionic liquids in surfactant aqueous solutions besides counterion effect, participation of micelles formation, and the effect on the properties of solvent. The effect of ionic liquids on surfactant solution can be regarded as the comprehensive effects of inorganic salt, cosurfactant, and cosolvent on surfactant solution. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100896z Exemplaires
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Titre : Oxidative degradation of MTBE by pyrite - activated persulfate : proposed reaction pathways Type de document : texte imprimé Auteurs : Chenju Liang, Auteur ; Yi-Yu Guo, Auteur ; Yi-Chi Chien, Auteur Année de publication : 2010 Article en page(s) : pp. 8858–8864 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oxidative degradation Résumé : This bench-scale study investigated the feasibility of activated persulfate (S2O82−) oxidation of methyl tert-butyl ether (MTBE), using pyrite (FeS2) as the source of ferrous ion activators. Under the FeS2-activated S2O82− condition, the sulfate free radical (SO4−•) is the predominant reactive species generated. The oxidation reactions were able to completely degrade MTBE when given sufficient doses of FeS2 and S2O82− and sufficient reaction time (e.g., 3 g FeS2/L and 5 g Na2S2O8/L within 4 h) and exhibited generation and subsequent degradation of the primary MTBE degradation intermediate products including tert-butyl formate, tert-butyl alcohol, methyl acetate, and acetone. The detailed reaction mechanism proposed for a SO4−•-driven oxidation process in this paper indicates that the destruction of MTBE most likely happens through α-hydrogen abstraction via attack of the SO4−• at the intermediate methoxy group. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100740d
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8858–8864[article] Oxidative degradation of MTBE by pyrite - activated persulfate : proposed reaction pathways [texte imprimé] / Chenju Liang, Auteur ; Yi-Yu Guo, Auteur ; Yi-Chi Chien, Auteur . - 2010 . - pp. 8858–8864.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8858–8864
Mots-clés : Oxidative degradation Résumé : This bench-scale study investigated the feasibility of activated persulfate (S2O82−) oxidation of methyl tert-butyl ether (MTBE), using pyrite (FeS2) as the source of ferrous ion activators. Under the FeS2-activated S2O82− condition, the sulfate free radical (SO4−•) is the predominant reactive species generated. The oxidation reactions were able to completely degrade MTBE when given sufficient doses of FeS2 and S2O82− and sufficient reaction time (e.g., 3 g FeS2/L and 5 g Na2S2O8/L within 4 h) and exhibited generation and subsequent degradation of the primary MTBE degradation intermediate products including tert-butyl formate, tert-butyl alcohol, methyl acetate, and acetone. The detailed reaction mechanism proposed for a SO4−•-driven oxidation process in this paper indicates that the destruction of MTBE most likely happens through α-hydrogen abstraction via attack of the SO4−• at the intermediate methoxy group. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100740d Exemplaires
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Titre : Gas hydrate phase equilibrium in the presence of ethylene glycol or methanol aqueous solution Type de document : texte imprimé Auteurs : Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur Année de publication : 2010 Article en page(s) : pp. 8865–8869 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gas Aqueous Solution Résumé : In this communication, experimental hydrate dissociation data for the ethane, carbon dioxide, or hydrogen sulfide + ethylene glycol + water system are first reported at 0.1, 0.2, 0.35, and 0.5 mass fractions of ethylene glycol in aqueous solution. The experimental data were generated using an isochoric pressure-search method. The experimental hydrate dissociation data are compared with the corresponding literature data and the experimental dissociation data for ethane, carbon dioxide, or hydrogen sulfide simple hydrates in the presence of pure water reported in the literature. A discussion is made on the reliability of the few sets of experimental hydrate dissociation data reported in the literature for the ethane, carbon dioxide, or hydrogen sulfide + ethylene glycol + water system. We finally report experimental hydrate dissociation data for the methane + methanol + water system at 0.55 and 0.65 mass fractions of methanol in aqueous solution. The experimental hydrate dissociation data are compared with the corresponding literature data and the experimental dissociation data for methane hydrates in the presence of pure water reported in the literature. It is shown that the few sets of experimental hydrate dissociation data reported in the literature for the methane + methanol + water system at high concentrations of methanol in aqueous solution may not be very reliable. A discussion is made on the inhibition effect of methanol at its very high concentration in aqueous solution. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100908d
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8865–8869[article] Gas hydrate phase equilibrium in the presence of ethylene glycol or methanol aqueous solution [texte imprimé] / Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur . - 2010 . - pp. 8865–8869.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8865–8869
Mots-clés : Gas Aqueous Solution Résumé : In this communication, experimental hydrate dissociation data for the ethane, carbon dioxide, or hydrogen sulfide + ethylene glycol + water system are first reported at 0.1, 0.2, 0.35, and 0.5 mass fractions of ethylene glycol in aqueous solution. The experimental data were generated using an isochoric pressure-search method. The experimental hydrate dissociation data are compared with the corresponding literature data and the experimental dissociation data for ethane, carbon dioxide, or hydrogen sulfide simple hydrates in the presence of pure water reported in the literature. A discussion is made on the reliability of the few sets of experimental hydrate dissociation data reported in the literature for the ethane, carbon dioxide, or hydrogen sulfide + ethylene glycol + water system. We finally report experimental hydrate dissociation data for the methane + methanol + water system at 0.55 and 0.65 mass fractions of methanol in aqueous solution. The experimental hydrate dissociation data are compared with the corresponding literature data and the experimental dissociation data for methane hydrates in the presence of pure water reported in the literature. It is shown that the few sets of experimental hydrate dissociation data reported in the literature for the methane + methanol + water system at high concentrations of methanol in aqueous solution may not be very reliable. A discussion is made on the inhibition effect of methanol at its very high concentration in aqueous solution. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100908d Exemplaires
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Titre : Revisit of the wall effect on the settling of cylindrical particles in the inertial regime Type de document : texte imprimé Auteurs : Raymond Lau, Auteur ; Meer Saiful Hassan, Auteur ; Wenyin Wong, Auteur Année de publication : 2010 Article en page(s) : pp. 8870–8876 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Cylindrical Particles Résumé : The wall effect on the settling of cylindrical particles in the inertial regime is revisited. This study covers particle Reynolds number from 600 to 16 100 and particle-length-to-diameter ratios (l/d) from 4 to 21. The wall factor (Ut/Ut,∞) is found to decrease initially as the particle-to-column diameter ratio (d/D) increases. When the wall effect becomes significant, Ut/Ut,∞ starts to increase with an increase in d/D due to a change of the particle orientation during settling. After Ut/Ut,∞ reaches a maximum, it decreases to 0 when d/D increases to 1. A semiempirical model is developed to predict the wall effect of settling of cylindrical particles over the whole range of d/D. The model shows good prediction to the experimental results and matches the wall factor models developed for spherical particles when l/d approaches 1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012807
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8870–8876[article] Revisit of the wall effect on the settling of cylindrical particles in the inertial regime [texte imprimé] / Raymond Lau, Auteur ; Meer Saiful Hassan, Auteur ; Wenyin Wong, Auteur . - 2010 . - pp. 8870–8876.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8870–8876
Mots-clés : Cylindrical Particles Résumé : The wall effect on the settling of cylindrical particles in the inertial regime is revisited. This study covers particle Reynolds number from 600 to 16 100 and particle-length-to-diameter ratios (l/d) from 4 to 21. The wall factor (Ut/Ut,∞) is found to decrease initially as the particle-to-column diameter ratio (d/D) increases. When the wall effect becomes significant, Ut/Ut,∞ starts to increase with an increase in d/D due to a change of the particle orientation during settling. After Ut/Ut,∞ reaches a maximum, it decreases to 0 when d/D increases to 1. A semiempirical model is developed to predict the wall effect of settling of cylindrical particles over the whole range of d/D. The model shows good prediction to the experimental results and matches the wall factor models developed for spherical particles when l/d approaches 1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012807 Exemplaires
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