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Recent advances in the synthesis, characterization, and applications of fulleropyrrolidines / Boris I. Kharisov in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 545–571 Titre : Recent advances in the synthesis, characterization, and applications of fulleropyrrolidines Type de document : texte imprimé Auteurs : Boris I. Kharisov, Auteur ; Oxana V. Kharissova, Auteur ; Marco Jimenez Gomez, Auteur ; Ubaldo Ortiz Mendez, Auteur Année de publication : 2009 Article en page(s) : p. 545–571 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Fulleropyrrolidines Résumé : Recent publications on C60- and C70-fulleropyrrolidines are reviewed. Main attention is paid to a series of novel dyads and triads with porphyrins and their metal complexes, ferrocene derivatives, S-containing ligands, calixarenes, crown-ethers, polymers, and enzymes, as well as to relatively simple ligand systems. A certain attention is paid to fulleropyrrolidine polyadducts, multifullerenopyrrolidines, and functionalization of carbon nanotubes with pyrrolidine-containing moieties. Synthesis techniques, physicochemical methods to study the compounds obtained, and their main applications are examined. Representative examples for synthesis and applications are tabulated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800602j [article] Recent advances in the synthesis, characterization, and applications of fulleropyrrolidines [texte imprimé] / Boris I. Kharisov, Auteur ; Oxana V. Kharissova, Auteur ; Marco Jimenez Gomez, Auteur ; Ubaldo Ortiz Mendez, Auteur . - 2009 . - p. 545–571. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 545–571 Mots-clés : Fulleropyrrolidines Résumé : Recent publications on C60- and C70-fulleropyrrolidines are reviewed. Main attention is paid to a series of novel dyads and triads with porphyrins and their metal complexes, ferrocene derivatives, S-containing ligands, calixarenes, crown-ethers, polymers, and enzymes, as well as to relatively simple ligand systems. A certain attention is paid to fulleropyrrolidine polyadducts, multifullerenopyrrolidines, and functionalization of carbon nanotubes with pyrrolidine-containing moieties. Synthesis techniques, physicochemical methods to study the compounds obtained, and their main applications are examined. Representative examples for synthesis and applications are tabulated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800602j

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Recent advances on the soluble carbon nanotubes / Boris I. Kharisov in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 572–590 Titre : Recent advances on the soluble carbon nanotubes Type de document : texte imprimé Auteurs : Boris I. Kharisov, Auteur ; Oxana V. Kharissova, Auteur ; Hector Leija Gutierrez, Auteur ; Ubaldo Ortiz Mendez, Auteur Année de publication : 2009 Article en page(s) : p. 572–590 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Carbon nanotubes Résumé : Recent literature (2000−2008) on the functionalization methods leading to soluble carbon nanotubes is reviewed. Carbon nanotubes (CNTs) can be solubilized by a series of methods, including their functionalization by the aryl diazonium process, use of elemental metals, simple inorganics, acids, esters, aldehydes, amines, aromatics, macrocycles, thiols, biomolecules, polymers, and using such techniques as pulsed streamer discharge, microwave treatment, cryogenic crushing, or γ-irradiation. In a difference with the functionalization methods applied in the past decade of the 20th century (frequent use of strong acidic media as a first step and further attachment of various organic moieties), current techniques involve a much wider number of functionalizing agents paying main attention to macrocycles, biomolecules, and polymers, as well as using such special techniques as use of radionuclides, irradiation, microwave treatment, or pulsed streamer discharge. Reactivity, physicochemical properties, and main applications of soluble CNTs are analyzed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800694f [article] Recent advances on the soluble carbon nanotubes [texte imprimé] / Boris I. Kharisov, Auteur ; Oxana V. Kharissova, Auteur ; Hector Leija Gutierrez, Auteur ; Ubaldo Ortiz Mendez, Auteur . - 2009 . - p. 572–590. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 572–590 Mots-clés : Carbon nanotubes Résumé : Recent literature (2000−2008) on the functionalization methods leading to soluble carbon nanotubes is reviewed. Carbon nanotubes (CNTs) can be solubilized by a series of methods, including their functionalization by the aryl diazonium process, use of elemental metals, simple inorganics, acids, esters, aldehydes, amines, aromatics, macrocycles, thiols, biomolecules, polymers, and using such techniques as pulsed streamer discharge, microwave treatment, cryogenic crushing, or γ-irradiation. In a difference with the functionalization methods applied in the past decade of the 20th century (frequent use of strong acidic media as a first step and further attachment of various organic moieties), current techniques involve a much wider number of functionalizing agents paying main attention to macrocycles, biomolecules, and polymers, as well as using such special techniques as use of radionuclides, irradiation, microwave treatment, or pulsed streamer discharge. Reactivity, physicochemical properties, and main applications of soluble CNTs are analyzed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800694f

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Mechanistic study on the oxidation of sulfacetamide by aqueous alkaline diperiodatoargentate(III) / Suresh D. Kulkarni in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.591–597 Titre : Mechanistic study on the oxidation of sulfacetamide by aqueous alkaline diperiodatoargentate(III) Type de document : texte imprimé Auteurs : Suresh D. Kulkarni, Auteur ; Praveen N. Naik, Auteur ; Sharanappa T. Nandibewoor, Auteur Année de publication : 2009 Article en page(s) : p.591–597 Note générale : chemical engeneering Langues : Anglais (eng) Mots-clés : Sulfacetamide Résumé : Oxidation of sulfacetamide (SUL), a sulfonamide drug by alkaline diperiodatoargentate(III) (DPA), a powerful oxidizing agent at 298 K and at a constant ionic strength of 0.50 mol/dm3, has been carried out spectrophotometrically at 360 nm. The results indicate that 3 mol of DPA consumed 1 mol of SUL (3:1). The oxidation product has been separated and characterized by IR and NMR spectral studies. The reaction is first order in [DPA] and has less than unit order in [SUL]. The rate constants increased with an increase in alkali concentration and decreased with increase in [IO4−]. Ionic strength and dielectric constant of the medium had negligible effect on the reaction rate. A mechanism has been proposed which explains the observed orders and experimental observations. Monoperiodatoargentate(III) (MPA) has been considered as the active species for the title reaction. The reaction proceeds through a SUL:MPA complex which decomposes in a slow step to give the p-hydroxylamine benzenesulfonamide and Ag(I) species. Further oxidation in the subsequent fast steps yeilds nitroso and nitro derivative of benzenesulfonamide, each transformation consuming 1 mol of MPA. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to the slow step of the mechanism are computed and discussed, and thermodynamic quantities are also determined. The probable active species of oxidation have been identified. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000474 [article] Mechanistic study on the oxidation of sulfacetamide by aqueous alkaline diperiodatoargentate(III) [texte imprimé] / Suresh D. Kulkarni, Auteur ; Praveen N. Naik, Auteur ; Sharanappa T. Nandibewoor, Auteur . - 2009 . - p.591–597. chemical engeneering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.591–597 Mots-clés : Sulfacetamide Résumé : Oxidation of sulfacetamide (SUL), a sulfonamide drug by alkaline diperiodatoargentate(III) (DPA), a powerful oxidizing agent at 298 K and at a constant ionic strength of 0.50 mol/dm3, has been carried out spectrophotometrically at 360 nm. The results indicate that 3 mol of DPA consumed 1 mol of SUL (3:1). The oxidation product has been separated and characterized by IR and NMR spectral studies. The reaction is first order in [DPA] and has less than unit order in [SUL]. The rate constants increased with an increase in alkali concentration and decreased with increase in [IO4−]. Ionic strength and dielectric constant of the medium had negligible effect on the reaction rate. A mechanism has been proposed which explains the observed orders and experimental observations. Monoperiodatoargentate(III) (MPA) has been considered as the active species for the title reaction. The reaction proceeds through a SUL:MPA complex which decomposes in a slow step to give the p-hydroxylamine benzenesulfonamide and Ag(I) species. Further oxidation in the subsequent fast steps yeilds nitroso and nitro derivative of benzenesulfonamide, each transformation consuming 1 mol of MPA. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to the slow step of the mechanism are computed and discussed, and thermodynamic quantities are also determined. The probable active species of oxidation have been identified. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000474

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Self-cleaning test of doped TiO2-coated Glass plates under solar exposure / Medina-Valtierra, Jorge in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 598–606 Titre : Self-cleaning test of doped TiO2-coated Glass plates under solar exposure Type de document : texte imprimé Auteurs : Medina-Valtierra, Jorge, Auteur ; Frausto-Reyes, Claudio, Auteur ; Jorge Ramírez-Ortiz, Auteur ; Gabriela Camarillo-Martínez, Auteur Année de publication : 2009 Article en page(s) : p. 598–606 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : photodegradation Résumé : Photocatalytic films of TiO2 doped with metal oxides, ZnFe2O4, ZnO, and CuO, were formed on glass plates by the ultraspinning method from Ti(IV) isopropoxide-based sol−gels. To test the self-cleaning properties of TiO2 films on glass, a layer of crystalline fluoranthene, a polycyclic aromatic compound, was placed over the glass by spraying and then exposing it to solar irradiation. The covering of fluoranthene on the 1 wt % metal oxide-doped anatase films was degraded nearly to 100% at 20 h of exposure time. Thus, the coated-glass transparency was recovered totally between 35 and 52 h of exposure time for the doped anatase film, which did not occur with anatase on glass, even after more than 85 h of solar irradiation. For some samples, a correlation was found between the weight losses of the solid compound and the intensity of the Raman vibration at 671 cm−1 during photocatalytic degradation. After 20 h of solar exposure, while the presence of fluoranthene was not detected by Raman spectroscopy, some glass plates presented ultrathin zones of degradation products. Regarding fluoranthene photodegradation and weight loss in the results when the different metal-oxide dopants were compared, a sequential efficiency was observed: ZnFe2O4 > CuO > ZnO. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008555 [article] Self-cleaning test of doped TiO2-coated Glass plates under solar exposure [texte imprimé] / Medina-Valtierra, Jorge, Auteur ; Frausto-Reyes, Claudio, Auteur ; Jorge Ramírez-Ortiz, Auteur ; Gabriela Camarillo-Martínez, Auteur . - 2009 . - p. 598–606. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 598–606 Mots-clés : photodegradation Résumé : Photocatalytic films of TiO2 doped with metal oxides, ZnFe2O4, ZnO, and CuO, were formed on glass plates by the ultraspinning method from Ti(IV) isopropoxide-based sol−gels. To test the self-cleaning properties of TiO2 films on glass, a layer of crystalline fluoranthene, a polycyclic aromatic compound, was placed over the glass by spraying and then exposing it to solar irradiation. The covering of fluoranthene on the 1 wt % metal oxide-doped anatase films was degraded nearly to 100% at 20 h of exposure time. Thus, the coated-glass transparency was recovered totally between 35 and 52 h of exposure time for the doped anatase film, which did not occur with anatase on glass, even after more than 85 h of solar irradiation. For some samples, a correlation was found between the weight losses of the solid compound and the intensity of the Raman vibration at 671 cm−1 during photocatalytic degradation. After 20 h of solar exposure, while the presence of fluoranthene was not detected by Raman spectroscopy, some glass plates presented ultrathin zones of degradation products. Regarding fluoranthene photodegradation and weight loss in the results when the different metal-oxide dopants were compared, a sequential efficiency was observed: ZnFe2O4 > CuO > ZnO. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008555

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N-chloro-alkoxy-s-triazine-based antimicrobial additives: preparation, characterization, and antimicrobial and Biofilm-controlling functions / Xinbo Sun in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 607–612 Titre : N-chloro-alkoxy-s-triazine-based antimicrobial additives: preparation, characterization, and antimicrobial and Biofilm-controlling functions Type de document : texte imprimé Auteurs : Xinbo Sun, Auteur ; Zhengbing Cao, Auteur ; Yuyu Sun, Auteur Année de publication : 2009 Article en page(s) : p. 607–612 Note générale : chemical ingineering Langues : Anglais (eng) Mots-clés : Antimicrobial-- Biofilm-Controlling Résumé : A series of N-chloro-alkoxy-s-triazine antimicrobial additives were synthesized in this study. The structures of the samples were confirmed with FTIR, 1H NMR, and thermal analyses. The N-chlorinated alkoxy-s-triazines provided potent antimicrobial activities against Staphylococcus aureus (S. aureus, Gram-positive bacteria) and Escherichia coli (E. coli, Gram-negative bacteria) under waterborne test conditions. The N-chlorinated alkoxy-s-triazines were incorporated into polyurethane, one of the most widely used polymer materials, as antimicrobial additives through solvent casting. Upon contact, the resultant films provided a total kill of S. aureus and E. coli, and they successfully prevented the formation of bacterial biofilms on film surfaces, pointing to great potential of the new N-chloro-alkoxy-s-triazine antimicrobial additive approach for a broad range of antimicrobial and Biofilm-controlling applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801110s [article] N-chloro-alkoxy-s-triazine-based antimicrobial additives: preparation, characterization, and antimicrobial and Biofilm-controlling functions [texte imprimé] / Xinbo Sun, Auteur ; Zhengbing Cao, Auteur ; Yuyu Sun, Auteur . - 2009 . - p. 607–612. chemical ingineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 607–612 Mots-clés : Antimicrobial-- Biofilm-Controlling Résumé : A series of N-chloro-alkoxy-s-triazine antimicrobial additives were synthesized in this study. The structures of the samples were confirmed with FTIR, 1H NMR, and thermal analyses. The N-chlorinated alkoxy-s-triazines provided potent antimicrobial activities against Staphylococcus aureus (S. aureus, Gram-positive bacteria) and Escherichia coli (E. coli, Gram-negative bacteria) under waterborne test conditions. The N-chlorinated alkoxy-s-triazines were incorporated into polyurethane, one of the most widely used polymer materials, as antimicrobial additives through solvent casting. Upon contact, the resultant films provided a total kill of S. aureus and E. coli, and they successfully prevented the formation of bacterial biofilms on film surfaces, pointing to great potential of the new N-chloro-alkoxy-s-triazine antimicrobial additive approach for a broad range of antimicrobial and Biofilm-controlling applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801110s

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New refreshable n-halamine polymeric biocides: n-chlorination of acyclic amide grafted cellulose / Song Liu in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 613–618 Titre : New refreshable n-halamine polymeric biocides: n-chlorination of acyclic amide grafted cellulose Type de document : texte imprimé Auteurs : Song Liu, Auteur ; Gang Sun, Auteur Année de publication : 2009 Article en page(s) : p. 613–618 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : antibacterial-- functions polymerization--processes Résumé : Acyclic N-halamine structures have demonstrated antibacterial functions similar to cyclic N-halamine. Precursors of acyclic halamine such as acrylamide and methacrylamide can be easily grafted onto surfaces of substrates via radical polymerization processes. However, due to easy hydrolysis of primary amides during chlorination and steric hindrance of secondary amide to conversion to acyclic halamine structures, the acyclic halamines still have limitations to many applications in preparation of antimicrobial materials. To reduce hydrolysis of amide during chlorination, particularly under alkaline conditions, addition of electrolytes such as NaCl was able to improve chlorination of polyacrylamide grafted cotton (chlorine content 458 ppm) with less than 10% hydrolysis under slightly basic (pH = 8) conditions. Both acidic conditions and the addition of salt can increase the chlorination of secondary amides and provide effective antibacterial functions on the treated cellulose (5 log reduction of E. coli in contact time of 120 min). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007902 [article] New refreshable n-halamine polymeric biocides: n-chlorination of acyclic amide grafted cellulose [texte imprimé] / Song Liu, Auteur ; Gang Sun, Auteur . - 2009 . - p. 613–618. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 613–618 Mots-clés : antibacterial-- functions polymerization--processes Résumé : Acyclic N-halamine structures have demonstrated antibacterial functions similar to cyclic N-halamine. Precursors of acyclic halamine such as acrylamide and methacrylamide can be easily grafted onto surfaces of substrates via radical polymerization processes. However, due to easy hydrolysis of primary amides during chlorination and steric hindrance of secondary amide to conversion to acyclic halamine structures, the acyclic halamines still have limitations to many applications in preparation of antimicrobial materials. To reduce hydrolysis of amide during chlorination, particularly under alkaline conditions, addition of electrolytes such as NaCl was able to improve chlorination of polyacrylamide grafted cotton (chlorine content 458 ppm) with less than 10% hydrolysis under slightly basic (pH = 8) conditions. Both acidic conditions and the addition of salt can increase the chlorination of secondary amides and provide effective antibacterial functions on the treated cellulose (5 log reduction of E. coli in contact time of 120 min). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007902

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Kinetic analysis of wheat straw oxidative pyrolysis using thermogravimetric analysis: statistical description and isoconversional kinetic analysis / Junmeng Cai in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 619–624 Titre : Kinetic analysis of wheat straw oxidative pyrolysis using thermogravimetric analysis: statistical description and isoconversional kinetic analysis Type de document : texte imprimé Auteurs : Junmeng Cai, Auteur ; Sibinuer Alimujiang, Auteur Année de publication : 2009 Article en page(s) : p. 619–624 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Kinetic Analysis Résumé : The oxidative pyrolysis kinetics of wheat straw was studied by thermogravimetric analysis (TGA) under oxygen dynamic atmosphere. Nonisothermal TGA data at three heating rates of 5, 10, and 20 K min−1 were analyzed. The kinetic conversion data calculated from the TGA data were fitted by the Weibull and logistic mixture models, and the corresponding statistical analyses were performed. The statistical results showed that the Weibull mixture model fitted the experimental data better than the logistic mixture model and can accurately reproduce the kinetic conversion data. Making use of the data predicted by the Weibull mixture model, some data required in the isoconversional kinetic analysis, such as α vs Tα, can be easily obtained. An iterative linear integral isoconversional method was developed and applied to evaluate the activation energy of the oxidative pyrolysis process of wheat straw. The Vyazovkin−Dollimore nonlinear integral isoconversional method was also used to calculate the activation energy. The results have shown that two isoconversional methods are equivalent for the estimation of the activation energy and the obtained activation energy is significantly dependent upon conversion for the oxidative pyrolysis process of wheat straw. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801299z [article] Kinetic analysis of wheat straw oxidative pyrolysis using thermogravimetric analysis: statistical description and isoconversional kinetic analysis [texte imprimé] / Junmeng Cai, Auteur ; Sibinuer Alimujiang, Auteur . - 2009 . - p. 619–624. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 619–624 Mots-clés : Kinetic Analysis Résumé : The oxidative pyrolysis kinetics of wheat straw was studied by thermogravimetric analysis (TGA) under oxygen dynamic atmosphere. Nonisothermal TGA data at three heating rates of 5, 10, and 20 K min−1 were analyzed. The kinetic conversion data calculated from the TGA data were fitted by the Weibull and logistic mixture models, and the corresponding statistical analyses were performed. The statistical results showed that the Weibull mixture model fitted the experimental data better than the logistic mixture model and can accurately reproduce the kinetic conversion data. Making use of the data predicted by the Weibull mixture model, some data required in the isoconversional kinetic analysis, such as α vs Tα, can be easily obtained. An iterative linear integral isoconversional method was developed and applied to evaluate the activation energy of the oxidative pyrolysis process of wheat straw. The Vyazovkin−Dollimore nonlinear integral isoconversional method was also used to calculate the activation energy. The results have shown that two isoconversional methods are equivalent for the estimation of the activation energy and the obtained activation energy is significantly dependent upon conversion for the oxidative pyrolysis process of wheat straw. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801299z

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Study of I−/I2 poisoning of fe2O3-based catalysts for the h2SO4 decomposition in the sulfur−iodine cycle for hydrogen production / Vincenzo Barbarossa in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 625–631 Titre : Study of I−/I2 poisoning of fe2O3-based catalysts for the h2SO4 decomposition in the sulfur−iodine cycle for hydrogen production Type de document : texte imprimé Auteurs : Vincenzo Barbarossa, Auteur ; Sergio Brutti, Auteur ; Bruno Brunetti ; Maurizio Diamanti, Auteur Année de publication : 2009 Article en page(s) : p 625–631 Note générale : chemical enginereeng Langues : Anglais (eng) Mots-clés : Hydrogen Production Résumé : The poisoning effect of I−/I2 mixtures on ferrous oxide based catalysts was investigated. These catalysts were used in the sulfuric acid thermal decomposition that is the highest endothermic step in the sulfur−iodine thermochemical cycle for hydrogen production by water splitting. This decomposition reaction needs a temperature as high as 1100 K to occur with a convenient thermodynamic yield for SO2 formation, and it is affected by kinetic limitations. Therefore only the use of a suitable catalyst allows for a large decrease in the H2SO4 decomposition temperature and attaining reaction yields close to the thermodynamic limits. I2 and HI present even in traces in the sulfuric acid feeding stream could lead to the poisoning of the catalyst used for the decomposition process and must therefore be minimized. In this study, two Fe2O3 catalysts supported on quartz wool and on alumina were used in the temperature range 873−1073 K in ordinary pressure conditions. The SO2 formation rates were measured before and after the catalyst poisoning. Kinetics measurements and scanning electron microscopy (SEM) analysis show that I−/I2 contamination reduced the catalytic activity by modifying its surface properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800064z [article] Study of I−/I2 poisoning of fe2O3-based catalysts for the h2SO4 decomposition in the sulfur−iodine cycle for hydrogen production [texte imprimé] / Vincenzo Barbarossa, Auteur ; Sergio Brutti, Auteur ; Bruno Brunetti ; Maurizio Diamanti, Auteur . - 2009 . - p 625–631. chemical enginereeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 625–631 Mots-clés : Hydrogen Production Résumé : The poisoning effect of I−/I2 mixtures on ferrous oxide based catalysts was investigated. These catalysts were used in the sulfuric acid thermal decomposition that is the highest endothermic step in the sulfur−iodine thermochemical cycle for hydrogen production by water splitting. This decomposition reaction needs a temperature as high as 1100 K to occur with a convenient thermodynamic yield for SO2 formation, and it is affected by kinetic limitations. Therefore only the use of a suitable catalyst allows for a large decrease in the H2SO4 decomposition temperature and attaining reaction yields close to the thermodynamic limits. I2 and HI present even in traces in the sulfuric acid feeding stream could lead to the poisoning of the catalyst used for the decomposition process and must therefore be minimized. In this study, two Fe2O3 catalysts supported on quartz wool and on alumina were used in the temperature range 873−1073 K in ordinary pressure conditions. The SO2 formation rates were measured before and after the catalyst poisoning. Kinetics measurements and scanning electron microscopy (SEM) analysis show that I−/I2 contamination reduced the catalytic activity by modifying its surface properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800064z

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Metal phosphate catalysts effective for degradation of sulfur hexafluoride / Daishin Kashiwagi in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 632–640 Titre : Metal phosphate catalysts effective for degradation of sulfur hexafluoride Type de document : texte imprimé Auteurs : Daishin Kashiwagi, Auteur ; Asami Takai, Auteur ; Takeshi Takubo, Auteur ; Katsutoshi Nagaoka, Auteur ; Takanori Inoue, Auteur Année de publication : 2009 Article en page(s) : p. 632–640 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : hydrolysisSulfur HexafluorideMetal Phosphate Résumé : SF6 decomposed stably over AlPO4, CePO4, YPO4, and Zr3(PO4)4 at 800−1000 K, but Ca2P2O7, Mg2P2O7, and Sr2P2O7 were less active. Active catalysts crystallized during the reaction. SO3, SO2F2, and HF were obtained as major products. SO3 was selectively formed over YPO4 and Zr3(PO4)4, but SO2F2 formed over AlPO4 and CePO4 in a significant selectivity at lower temperatures. Decomposition activity was independent of the concentration of oxygen, but it was dependent on the concentration of water vapor, suggesting that hydrolysis is the essential reaction. Catalytic activity was independent of the acidity of the catalysts. Catalytic activity was independent of the amount of surface hydroxyls, but it was correlated with the concentration of surface hydroxyls. From an analogy of hydrolysis of CCl2F2 on AlPO4, degradation may proceed via a similar bidentate surface intermediate, OsurfaceH···F(SF4)F···HOsurface, in which two fluorine atoms of SF6 interacted with two surface hydroxyls. AlPO4 showed a steady activity and high selectivity at 843 K for 25 h, suggesting a long catalyst life. AlF3 was significantly less active than metal phosphates. This suggests that development of the catalysts which are not transformed into metal fluorides is important. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001099 [article] Metal phosphate catalysts effective for degradation of sulfur hexafluoride [texte imprimé] / Daishin Kashiwagi, Auteur ; Asami Takai, Auteur ; Takeshi Takubo, Auteur ; Katsutoshi Nagaoka, Auteur ; Takanori Inoue, Auteur . - 2009 . - p. 632–640. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 632–640 Mots-clés : hydrolysisSulfur HexafluorideMetal Phosphate Résumé : SF6 decomposed stably over AlPO4, CePO4, YPO4, and Zr3(PO4)4 at 800−1000 K, but Ca2P2O7, Mg2P2O7, and Sr2P2O7 were less active. Active catalysts crystallized during the reaction. SO3, SO2F2, and HF were obtained as major products. SO3 was selectively formed over YPO4 and Zr3(PO4)4, but SO2F2 formed over AlPO4 and CePO4 in a significant selectivity at lower temperatures. Decomposition activity was independent of the concentration of oxygen, but it was dependent on the concentration of water vapor, suggesting that hydrolysis is the essential reaction. Catalytic activity was independent of the acidity of the catalysts. Catalytic activity was independent of the amount of surface hydroxyls, but it was correlated with the concentration of surface hydroxyls. From an analogy of hydrolysis of CCl2F2 on AlPO4, degradation may proceed via a similar bidentate surface intermediate, OsurfaceH···F(SF4)F···HOsurface, in which two fluorine atoms of SF6 interacted with two surface hydroxyls. AlPO4 showed a steady activity and high selectivity at 843 K for 25 h, suggesting a long catalyst life. AlF3 was significantly less active than metal phosphates. This suggests that development of the catalysts which are not transformed into metal fluorides is important. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001099

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Activation of methane over perovskite catalysts / Jun Li in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 641–646 Titre : Activation of methane over perovskite catalysts Type de document : texte imprimé Auteurs : Jun Li, Auteur ; Ling Zhao, Auteur ; Lu Guanzhong, Auteur Année de publication : 2009 Article en page(s) : p 641–646 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Electrochemical measurements Résumé : Perovskite-type catalysts group one Ln0.6Sr0.4FexCo1−xO3 (Ln = Nd, Pr, Gd, Sm, La, 0 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008007#afn1 [article] Activation of methane over perovskite catalysts [texte imprimé] / Jun Li, Auteur ; Ling Zhao, Auteur ; Lu Guanzhong, Auteur . - 2009 . - p 641–646. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 641–646 Mots-clés : Electrochemical measurements Résumé : Perovskite-type catalysts group one Ln0.6Sr0.4FexCo1−xO3 (Ln = Nd, Pr, Gd, Sm, La, 0 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008007#afn1

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Kinetic modeling of limonene epoxidation over pw-amberlite / Barrera Zapata, Rolando in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 647–653 Titre : Kinetic modeling of limonene epoxidation over pw-amberlite Type de document : texte imprimé Auteurs : Barrera Zapata, Rolando, Auteur ; Aida Luz Villa, Auteur ; Montes de Correa, Consuelo, Auteur Année de publication : 2009 Article en page(s) : p 647–653 Langues : Anglais (eng) Mots-clés : kinetics--limonene Résumé : The kinetics of limonene epoxidation catalyzed by PW-Amberlite under triphasic conditions is described. A mechanistic pathway was postulated, and a heterogeneous kinetic model was derived following pseudo-stationary-state theory. Using adsorption parameters that were estimated from independent binary adsorption experiments, the resulting kinetic model fitted the experimental data quite well. Note de contenu : chemical engenireeng En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800822n [article] Kinetic modeling of limonene epoxidation over pw-amberlite [texte imprimé] / Barrera Zapata, Rolando, Auteur ; Aida Luz Villa, Auteur ; Montes de Correa, Consuelo, Auteur . - 2009 . - p 647–653. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 647–653 Mots-clés : kinetics--limonene Résumé : The kinetics of limonene epoxidation catalyzed by PW-Amberlite under triphasic conditions is described. A mechanistic pathway was postulated, and a heterogeneous kinetic model was derived following pseudo-stationary-state theory. Using adsorption parameters that were estimated from independent binary adsorption experiments, the resulting kinetic model fitted the experimental data quite well. Note de contenu : chemical engenireeng En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800822n

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Thermal decomposition kinetics of propylcyclohexane / Jason A Widegren in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 654–659 Titre : Thermal decomposition kinetics of propylcyclohexane Type de document : texte imprimé Auteurs : Jason A Widegren, Auteur ; Thomas J. Bruno, Auteur Année de publication : 2009 Article en page(s) : p. 654–659 Note générale : chemical ingenireeng Langues : Anglais (eng) Mots-clés : propylcyclohexane Résumé : As part of a large-scale thermophysical property measurement project, the decomposition kinetics of propylcyclohexane was investigated. Decomposition reactions were performed at 375, 400, 425, and 450 °C in stainless steel ampule reactors. At each temperature, the extent of decomposition was determined as a function of time by gas chromatography. These data were used to derive first-order rate constants for the decomposition of propylcyclohexane. Decomposition rate constants ranged from 3.66 × 10−7 s−1 at 375 °C to 8.63 × 10−5 s−1 at 450 °C. Among other things, these rate constants are useful for planning property measurements at high temperatures. Based on the amount of time required for 1% of the sample to decompose (t0.01), we found that allowable instrument residence times ranged from about 8 h at 375 °C to about 2 min at 450 °C. The kinetic data were also used to determine Arrhenius parameters of A = 2.56 × 1016 s−1 and Ea = 283 kJ·mol−1. In addition to the decomposition kinetics, we have also done a GC−MS analysis in order to identify the most abundant decomposition products. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008988 [article] Thermal decomposition kinetics of propylcyclohexane [texte imprimé] / Jason A Widegren, Auteur ; Thomas J. Bruno, Auteur . - 2009 . - p. 654–659. chemical ingenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 654–659 Mots-clés : propylcyclohexane Résumé : As part of a large-scale thermophysical property measurement project, the decomposition kinetics of propylcyclohexane was investigated. Decomposition reactions were performed at 375, 400, 425, and 450 °C in stainless steel ampule reactors. At each temperature, the extent of decomposition was determined as a function of time by gas chromatography. These data were used to derive first-order rate constants for the decomposition of propylcyclohexane. Decomposition rate constants ranged from 3.66 × 10−7 s−1 at 375 °C to 8.63 × 10−5 s−1 at 450 °C. Among other things, these rate constants are useful for planning property measurements at high temperatures. Based on the amount of time required for 1% of the sample to decompose (t0.01), we found that allowable instrument residence times ranged from about 8 h at 375 °C to about 2 min at 450 °C. The kinetic data were also used to determine Arrhenius parameters of A = 2.56 × 1016 s−1 and Ea = 283 kJ·mol−1. In addition to the decomposition kinetics, we have also done a GC−MS analysis in order to identify the most abundant decomposition products. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008988

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Synthesis of benzoxazole via the beckmann rearrangement of salicylaldoxime on protonated zeolites: a green continuous process / Bejoy Thomas in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 660–670 Titre : Synthesis of benzoxazole via the beckmann rearrangement of salicylaldoxime on protonated zeolites: a green continuous process Type de document : texte imprimé Auteurs : Bejoy Thomas, Auteur ; George Jino, Auteur ; S. Sugunan, Auteur Année de publication : 2009 Article en page(s) : p. 660–670 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Benzoxazole Résumé : Benzoxazole was prepared through the Beckmann rearrangement of salicylaldoxime using a series of H-zeolites, K-10 montmorillonite clay, and some common oxide catalysts under well-optimized reaction conditions of temperature, weight hourly space velocity, and catalyst amount. Salicylaldoxime underwent a facile 1,2-o-hydroxyphenyl shift followed by an intramolecular cyclization to yield benzoxazole. Syn-anti isomerization of the oxime on acid catalysts is a key step in the reaction. o-Hydroxybenzonitrile, o-hydroxybenzamide, and salicylaldehyde were the main byproduct. We have observed definite correlations between acid sites distribution of the catalysts and different products formed during the reaction. Catalysts were susceptible for deactivation and the decrease in the percentage conversion of oxime with time is associated with a corresponding increase in the acid hydrolysis producing salicylaldehyde at later stages of the reaction. However, the deactivated catalysts can be regenerated without considerable loss of catalytic activity through an oxidative treatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800913q [article] Synthesis of benzoxazole via the beckmann rearrangement of salicylaldoxime on protonated zeolites: a green continuous process [texte imprimé] / Bejoy Thomas, Auteur ; George Jino, Auteur ; S. Sugunan, Auteur . - 2009 . - p. 660–670. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 660–670 Mots-clés : Benzoxazole Résumé : Benzoxazole was prepared through the Beckmann rearrangement of salicylaldoxime using a series of H-zeolites, K-10 montmorillonite clay, and some common oxide catalysts under well-optimized reaction conditions of temperature, weight hourly space velocity, and catalyst amount. Salicylaldoxime underwent a facile 1,2-o-hydroxyphenyl shift followed by an intramolecular cyclization to yield benzoxazole. Syn-anti isomerization of the oxime on acid catalysts is a key step in the reaction. o-Hydroxybenzonitrile, o-hydroxybenzamide, and salicylaldehyde were the main byproduct. We have observed definite correlations between acid sites distribution of the catalysts and different products formed during the reaction. Catalysts were susceptible for deactivation and the decrease in the percentage conversion of oxime with time is associated with a corresponding increase in the acid hydrolysis producing salicylaldehyde at later stages of the reaction. However, the deactivated catalysts can be regenerated without considerable loss of catalytic activity through an oxidative treatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800913q

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Modification of multimetallic naphtha-reforming catalysts by indium addition / Viviana M. Benitez in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 671–676 Titre : Modification of multimetallic naphtha-reforming catalysts by indium addition Type de document : texte imprimé Auteurs : Viviana M. Benitez, Auteur ; Carlos R. Vera, Auteur ; María C. Rangel, Auteur ; Juan C. Yori, Auteur Année de publication : 2009 Article en page(s) : p. 671–676 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Metal catalytic Résumé : Pt−Re−Ge/Al2O3 and Pt−Re−Sn/Al2O3 trimetallic naphtha-reforming catalysts were modified by the addition of indium. This additive negatively modified both the acid and metal functions of the catalysts. It produced a decrease in the activity in acid-catalyzed reactions such as the isomerization of n-pentane. Metal catalytic properties were inhibited, and the capacity for CO chemisorption also decreased. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800933s [article] Modification of multimetallic naphtha-reforming catalysts by indium addition [texte imprimé] / Viviana M. Benitez, Auteur ; Carlos R. Vera, Auteur ; María C. Rangel, Auteur ; Juan C. Yori, Auteur . - 2009 . - p. 671–676. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 671–676 Mots-clés : Metal catalytic Résumé : Pt−Re−Ge/Al2O3 and Pt−Re−Sn/Al2O3 trimetallic naphtha-reforming catalysts were modified by the addition of indium. This additive negatively modified both the acid and metal functions of the catalysts. It produced a decrease in the activity in acid-catalyzed reactions such as the isomerization of n-pentane. Metal catalytic properties were inhibited, and the capacity for CO chemisorption also decreased. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800933s

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Kinetic studies of carbon dioxide reforming of methane over ni−co/al−mg−o bimetallic catalyst / Jianguo Zhang in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 677–684 Titre : Kinetic studies of carbon dioxide reforming of methane over ni−co/al−mg−o bimetallic catalyst Type de document : texte imprimé Auteurs : Jianguo Zhang, Auteur ; Hui Wang, Auteur ; Ajay Kumar Dalai, Auteur Année de publication : 2009 Article en page(s) : p. 677–684 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Bimetallic Catalyst Résumé : The kinetics of CO2 reforming with CH4 over a Ni−Co/Al−Mg−O bimetallic catalyst was investigated in a fixed bed reactor at a temperature range of 650−750 °C and the partial pressures of CO2 and CH4 ranging from 30 to 190 kPa. Owing to the simultaneous occurrence of the CO2 reforming reaction and the reverse water−gas shift reaction (RWGS) in the system, the apparent activation energies with respect to reactant consumption and product formation were found different and they are 69.4 and 25.9 kJ/mol for CH4 and CO2 consumption and 85.1 and 61.8 kJ/mol for H2 and CO formation, respectively. It was also found that the reforming rate in terms of CH4 consumption was less sensitive to CO2 partial pressures but had stronger dependence on CH4 partial pressures. At a constant CH4 partial pressure, the increase in CO2 partial pressure did not cause significant change in the reforming rate, whereas at a constant CO2 partial pressure the reforming rate increased with the increase in CH4 partial pressure. The increase in extra CO2 at a constant CH4 pressure led to decreases in hydrogen (H2) formation but increase in carbon monoxide (CO) formation due to the simultaneous occurrence of the reverse water-gas shift reaction. A Langmuir−Hinshelwood (L–H) model was also developed assuming that the dissociation of CH4 and the reaction between the carbon species and the activated carbon dioxide are the rate determining steps over the Ni–Co/Al–Mg–O. It satisfactorily fits the experimental data as well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801078p [article] Kinetic studies of carbon dioxide reforming of methane over ni−co/al−mg−o bimetallic catalyst [texte imprimé] / Jianguo Zhang, Auteur ; Hui Wang, Auteur ; Ajay Kumar Dalai, Auteur . - 2009 . - p. 677–684. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 677–684 Mots-clés : Bimetallic Catalyst Résumé : The kinetics of CO2 reforming with CH4 over a Ni−Co/Al−Mg−O bimetallic catalyst was investigated in a fixed bed reactor at a temperature range of 650−750 °C and the partial pressures of CO2 and CH4 ranging from 30 to 190 kPa. Owing to the simultaneous occurrence of the CO2 reforming reaction and the reverse water−gas shift reaction (RWGS) in the system, the apparent activation energies with respect to reactant consumption and product formation were found different and they are 69.4 and 25.9 kJ/mol for CH4 and CO2 consumption and 85.1 and 61.8 kJ/mol for H2 and CO formation, respectively. It was also found that the reforming rate in terms of CH4 consumption was less sensitive to CO2 partial pressures but had stronger dependence on CH4 partial pressures. At a constant CH4 partial pressure, the increase in CO2 partial pressure did not cause significant change in the reforming rate, whereas at a constant CO2 partial pressure the reforming rate increased with the increase in CH4 partial pressure. The increase in extra CO2 at a constant CH4 pressure led to decreases in hydrogen (H2) formation but increase in carbon monoxide (CO) formation due to the simultaneous occurrence of the reverse water-gas shift reaction. A Langmuir−Hinshelwood (L–H) model was also developed assuming that the dissociation of CH4 and the reaction between the carbon species and the activated carbon dioxide are the rate determining steps over the Ni–Co/Al–Mg–O. It satisfactorily fits the experimental data as well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801078p

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Kinetics of polycarbonate glycolysis in ethylene glycol / Dongpil Kim in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 685–691 Titre : Kinetics of polycarbonate glycolysis in ethylene glycol Type de document : texte imprimé Auteurs : Dongpil Kim, Auteur ; Bo-kyung Kim, Auteur ; Youngmin Cho, Auteur ; Myungwan Han, Auteur Année de publication : 2009 Article en page(s) : p. 685–691 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : polycarbonate Résumé : Depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The depolymerized products were identified by GC/MS and FTIR spectroscopy. The effects of operation variables such as reaction time, reaction temperature, ethylene glycol/polycarbonate (EG/PC) weight ratio, and the kinetics of glycolysis were studied. A maximum yield of BPA of 95.6% was achieved at a reaction temperature of 220 °C for 85 min with an EG/PC weight ratio 4. It was found that the depolymerization reaction has two different activation energies, indicating that the reaction occurs in series. A new model was proposed to explain the depolymerization reaction which consists of a series of reactions: random scission from high molecular weight PC to its solid oligomer, dissolution from the solid oligomer to liquid oligomer, and homogeneous degradation from the liquid oligomer to its monomer, BPA. The activation energies were found to be 98.9 kJ/mol for the random scission reaction, 32.7 kJ/mol for the dissolution, and 355.8 kJ/mol for the homogeneous reaction, respectively. The predicted values by the proposed model were shown in good agreement with the experimental ones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010947 [article] Kinetics of polycarbonate glycolysis in ethylene glycol [texte imprimé] / Dongpil Kim, Auteur ; Bo-kyung Kim, Auteur ; Youngmin Cho, Auteur ; Myungwan Han, Auteur . - 2009 . - p. 685–691. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 685–691 Mots-clés : polycarbonate Résumé : Depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The depolymerized products were identified by GC/MS and FTIR spectroscopy. The effects of operation variables such as reaction time, reaction temperature, ethylene glycol/polycarbonate (EG/PC) weight ratio, and the kinetics of glycolysis were studied. A maximum yield of BPA of 95.6% was achieved at a reaction temperature of 220 °C for 85 min with an EG/PC weight ratio 4. It was found that the depolymerization reaction has two different activation energies, indicating that the reaction occurs in series. A new model was proposed to explain the depolymerization reaction which consists of a series of reactions: random scission from high molecular weight PC to its solid oligomer, dissolution from the solid oligomer to liquid oligomer, and homogeneous degradation from the liquid oligomer to its monomer, BPA. The activation energies were found to be 98.9 kJ/mol for the random scission reaction, 32.7 kJ/mol for the dissolution, and 355.8 kJ/mol for the homogeneous reaction, respectively. The predicted values by the proposed model were shown in good agreement with the experimental ones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010947

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Preparation and properties of microspherical alumina with a magnetic core/shell structure / Jun-Ting Feng in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.692–697 Titre : Preparation and properties of microspherical alumina with a magnetic core/shell structure Type de document : texte imprimé Auteurs : Jun-Ting Feng, Auteur ; Lin, Yan-Jun, Auteur ; Feng Li, Auteur ; David G. Evans, Auteur Année de publication : 2009 Article en page(s) : p.692–697 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Microspherical -- Alumina Résumé : A series of Ni2+−Co2+−Fe2+−Fe3+−SO42− layered double hydroxide precursors with different Ni/Co ratios have been synthesized by a method involving separate nucleation and aging steps. After calcination at 900 °C, the corresponding Ni1-xCoxFe oxides were obtained. Vibrating sample magnetometry indicated that the Ni1-xCoxFe oxide samples not only had high specific saturation magnetization, but also low coercivity and remanence. Ni1-xCoxFe oxides showed the optimum combination of magnetic properties for x = 0.2. Silica was coated onto the surface of Ni0.8Co0.2Fe oxide particles, and the coated particles were used as magnetic cores to prepare magnetic Ni0.8Co0.2Fe oxide/SiO2/γ-Al2O3 particles by hydrolysis of aluminum isopropoxide. After repeating the hydrolysis twice more, Ni0.8Co0.2Fe oxide/SiO2/γ-Al2O3 particles with about 20 wt % Ni0.8Co0.2Fe oxide were obtained and shown to be suitable for practical applications as a magnetic catalyst or catalyst support by virtue of their efficacious magnetic properties and pore structure. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801098k [article] Preparation and properties of microspherical alumina with a magnetic core/shell structure [texte imprimé] / Jun-Ting Feng, Auteur ; Lin, Yan-Jun, Auteur ; Feng Li, Auteur ; David G. Evans, Auteur . - 2009 . - p.692–697. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.692–697 Mots-clés : Microspherical -- Alumina Résumé : A series of Ni2+−Co2+−Fe2+−Fe3+−SO42− layered double hydroxide precursors with different Ni/Co ratios have been synthesized by a method involving separate nucleation and aging steps. After calcination at 900 °C, the corresponding Ni1-xCoxFe oxides were obtained. Vibrating sample magnetometry indicated that the Ni1-xCoxFe oxide samples not only had high specific saturation magnetization, but also low coercivity and remanence. Ni1-xCoxFe oxides showed the optimum combination of magnetic properties for x = 0.2. Silica was coated onto the surface of Ni0.8Co0.2Fe oxide particles, and the coated particles were used as magnetic cores to prepare magnetic Ni0.8Co0.2Fe oxide/SiO2/γ-Al2O3 particles by hydrolysis of aluminum isopropoxide. After repeating the hydrolysis twice more, Ni0.8Co0.2Fe oxide/SiO2/γ-Al2O3 particles with about 20 wt % Ni0.8Co0.2Fe oxide were obtained and shown to be suitable for practical applications as a magnetic catalyst or catalyst support by virtue of their efficacious magnetic properties and pore structure. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801098k

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Synthesis, characterization, and hydrodesulfurization activity of new mesoporous carbon supported transition metal sulfide catalysts / Murid Hussain in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 698–707 Titre : Synthesis, characterization, and hydrodesulfurization activity of new mesoporous carbon supported transition metal sulfide catalysts Type de document : texte imprimé Auteurs : Murid Hussain, Auteur ; Son-Ki Ihm, Auteur Année de publication : 2009 Article en page(s) : p. 698–707 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : hydrodesulphurization Résumé : The potential of sulfided Mo, Co, and CoMo catalysts supported on two different carbon mesostructures by KAIST-1 and 3 (CMK-1 and 3) for hydrodesulphurization (HDS) of thiophene at specific conditions was explored to investigate the effect of different pore sizes, surface functional groups, metal dispersion, and presulfidation temperature. Co/CMK catalysts were superior to Mo/CMK catalysts on the basis of same metal loading. The synergistic effect was found at Co/Mo ratio of 5/5. Sulfidation on carbon supported catalysts was favored at lower temperature of 300 °C, whereas higher temperature of 400 and 500 °C showed a more favorable effect on alumina supported catalysts. CMK-3 supported CoMo catalysts were superior to all other catalysts due to larger pore size and higher acidic surface functional groups. CMK-3 oxidized with nitric acid showed even better performance for CoMo (5:5) supported catalysts since the increased surface functional groups might induce better dispersion leading to higher HDS activity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801229y [article] Synthesis, characterization, and hydrodesulfurization activity of new mesoporous carbon supported transition metal sulfide catalysts [texte imprimé] / Murid Hussain, Auteur ; Son-Ki Ihm, Auteur . - 2009 . - p. 698–707. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 698–707 Mots-clés : hydrodesulphurization Résumé : The potential of sulfided Mo, Co, and CoMo catalysts supported on two different carbon mesostructures by KAIST-1 and 3 (CMK-1 and 3) for hydrodesulphurization (HDS) of thiophene at specific conditions was explored to investigate the effect of different pore sizes, surface functional groups, metal dispersion, and presulfidation temperature. Co/CMK catalysts were superior to Mo/CMK catalysts on the basis of same metal loading. The synergistic effect was found at Co/Mo ratio of 5/5. Sulfidation on carbon supported catalysts was favored at lower temperature of 300 °C, whereas higher temperature of 400 and 500 °C showed a more favorable effect on alumina supported catalysts. CMK-3 supported CoMo catalysts were superior to all other catalysts due to larger pore size and higher acidic surface functional groups. CMK-3 oxidized with nitric acid showed even better performance for CoMo (5:5) supported catalysts since the increased surface functional groups might induce better dispersion leading to higher HDS activity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801229y

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Kinetics of solvent-free lipase-catalyzed production of monoacylglycerols from olive oil in aerosol-ot surfactant / Karina G. Fiametti in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 708–712 Titre : Kinetics of solvent-free lipase-catalyzed production of monoacylglycerols from olive oil in aerosol-ot surfactant Type de document : texte imprimé Auteurs : Karina G. Fiametti, Auteur ; Suzimara Rovani, Auteur ; Débora de Oliveira, Auteur ; Marcos L. Corazza, Auteur Année de publication : 2009 Article en page(s) : p 708–712 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Monoacylglycerols Résumé : This work reports a kinetic study of monoacylglycerols production from olive oil in a solvent-free system using a commercial lipase in the presence of surfactant. For this purpose, a commercial immobilized lipase (Novozym 435) was employed as catalyst and sodium (bis-2-ethylhexyl) sulfosuccinate (Aerosol-OT or AOT) as surfactant. The experiments were performed in batch mode, recording the reaction kinetics over temperature range of 40−80 °C, enzyme concentration of 1−10 wt %, AOT addition of 5−20 wt %, and glycerol to oil molar ratio of 1:1−1:3. Results showed that lipase-catalyzed glycerolysis in a solvent-free system with the addition of AOT surfactant might be a promising route, as high reaction conversions to monoacylglycerols, greater than 70%, were achieved at mild temperatures and relatively low enzyme concentrations (∼5−7.5 wt %) in short reaction times (1 h). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013956 [article] Kinetics of solvent-free lipase-catalyzed production of monoacylglycerols from olive oil in aerosol-ot surfactant [texte imprimé] / Karina G. Fiametti, Auteur ; Suzimara Rovani, Auteur ; Débora de Oliveira, Auteur ; Marcos L. Corazza, Auteur . - 2009 . - p 708–712. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 708–712 Mots-clés : Monoacylglycerols Résumé : This work reports a kinetic study of monoacylglycerols production from olive oil in a solvent-free system using a commercial lipase in the presence of surfactant. For this purpose, a commercial immobilized lipase (Novozym 435) was employed as catalyst and sodium (bis-2-ethylhexyl) sulfosuccinate (Aerosol-OT or AOT) as surfactant. The experiments were performed in batch mode, recording the reaction kinetics over temperature range of 40−80 °C, enzyme concentration of 1−10 wt %, AOT addition of 5−20 wt %, and glycerol to oil molar ratio of 1:1−1:3. Results showed that lipase-catalyzed glycerolysis in a solvent-free system with the addition of AOT surfactant might be a promising route, as high reaction conversions to monoacylglycerols, greater than 70%, were achieved at mild temperatures and relatively low enzyme concentrations (∼5−7.5 wt %) in short reaction times (1 h). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013956

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Combined methane CO2 reforming and dehydroaromatization for enhancing the catalyst stability / Songdong Yao in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 713–718 Titre : Combined methane CO2 reforming and dehydroaromatization for enhancing the catalyst stability Type de document : texte imprimé Auteurs : Songdong Yao, Auteur ; Lijun Gu, Auteur ; Changyong Sun, Auteur Année de publication : 2009 Article en page(s) : p. 713–718 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Catalyst Stability En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014582 [article] Combined methane CO2 reforming and dehydroaromatization for enhancing the catalyst stability [texte imprimé] / Songdong Yao, Auteur ; Lijun Gu, Auteur ; Changyong Sun, Auteur . - 2009 . - p. 713–718. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 713–718 Mots-clés : Catalyst Stability En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014582

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Hydrodynamics in sulzer smx static mixer with air/water system / Chandra Mouli R Madhuranthakam in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Titre : Hydrodynamics in sulzer smx static mixer with air/water system Type de document : texte imprimé Auteurs : Chandra Mouli R Madhuranthakam, Auteur ; Qinmin Pan, Auteur ; Garry L. Rempel, Auteur Année de publication : 2009 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Hydrodynamics Résumé : A Sulzer static mixer with SMX internal structure is investigated for its performance with respect to flow behavior, gas hold-up, and mass transfer rates in an air/water system. The reactor consists of 18 such elements arranged in a line with the angle between successive elements being 90°. The void fraction in the reactor is 0.95. The length of the reactor is 90 cm, with an 6.3 cm internal diameter, and is operated cocurrently with vertical up-flow. The fluids used are air and water. In all the experiments performed in the static mixer, water is the continuous phase and air is the dispersed phase. Experiments are conducted with these fluids under laminar flow conditions. With 18 elements in the reactor, Peclet numbers of up to 100 were obtained in laminar flow regime, thus eliminating the parabolic velocity profile (which usually occurs in laminar flow) to a maximum extent. A gas hold-up of 15% was achieved at lower liquid flow rates and higher gas flow rates while mass transfer coefficients of up to 0.037 s−1 were achieved. Empirical correlations for Peclet number, gas hold-up, and overall mass transfer coefficient as a function of liquid-side and gas-side Reynolds numbers are obtained. From the experimental results, it was observed that a reactor with the Sulzer SMX internal structure would ensure plug flow behavior with enhanced radial mixing in addition to providing superior mass transfer coefficients and gas hold-up. Finally, the higher mass transfer coefficients achieved in the current study are compared to those obtained in a tube filled with Sulzer SMV packing and a dynamic mixer for identical power dissipation conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801407y [article] Hydrodynamics in sulzer smx static mixer with air/water system [texte imprimé] / Chandra Mouli R Madhuranthakam, Auteur ; Qinmin Pan, Auteur ; Garry L. Rempel, Auteur . - 2009. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Mots-clés : Hydrodynamics Résumé : A Sulzer static mixer with SMX internal structure is investigated for its performance with respect to flow behavior, gas hold-up, and mass transfer rates in an air/water system. The reactor consists of 18 such elements arranged in a line with the angle between successive elements being 90°. The void fraction in the reactor is 0.95. The length of the reactor is 90 cm, with an 6.3 cm internal diameter, and is operated cocurrently with vertical up-flow. The fluids used are air and water. In all the experiments performed in the static mixer, water is the continuous phase and air is the dispersed phase. Experiments are conducted with these fluids under laminar flow conditions. With 18 elements in the reactor, Peclet numbers of up to 100 were obtained in laminar flow regime, thus eliminating the parabolic velocity profile (which usually occurs in laminar flow) to a maximum extent. A gas hold-up of 15% was achieved at lower liquid flow rates and higher gas flow rates while mass transfer coefficients of up to 0.037 s−1 were achieved. Empirical correlations for Peclet number, gas hold-up, and overall mass transfer coefficient as a function of liquid-side and gas-side Reynolds numbers are obtained. From the experimental results, it was observed that a reactor with the Sulzer SMX internal structure would ensure plug flow behavior with enhanced radial mixing in addition to providing superior mass transfer coefficients and gas hold-up. Finally, the higher mass transfer coefficients achieved in the current study are compared to those obtained in a tube filled with Sulzer SMV packing and a dynamic mixer for identical power dissipation conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801407y

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Catalytic hydrolysis of urea with fly ash for generation of ammonia in a batch reactor for flue gas conditioning and nox reduction / J.N. Sahu in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Titre : Catalytic hydrolysis of urea with fly ash for generation of ammonia in a batch reactor for flue gas conditioning and nox reduction Type de document : texte imprimé Auteurs : J.N. Sahu, Auteur ; P. Gangadharan, Auteur ; Anada V. Patwardhan, Auteur Année de publication : 2009 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Catalytic Hydrolysis Résumé : Ammonia is a highly volatile noxious material with adverse physiological effects, which become intolerable even at very low concentrations and present substantial environmental and operating hazards and risk. Yet ammonia has long been known to be used for feedstock of flue gas conditioning and NOx reduction. Urea as the source of ammonia for the production of ammonia has the obvious advantages that no ammonia shipping, handling, and storage is required. The process of this invention minimizes the risks and hazards associated with the transport, storage, and use of anhydrous and aqueous ammonia. Yet no such rapid urea conversion process is available as per requirement of high conversion in shorter time, so here we study the catalytic hydrolysis of urea for fast conversion in a batch reactor. The catalyst used in this study is fly ash, a waste material originating in great amounts in combustion processes. A number of experiments were carried out in a batch reactor at different catalytic doses, temperatures, times, and at a constant concentration of urea solution 10% by weight, and equilibrium and kinetic studies have been made. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801491j [article] Catalytic hydrolysis of urea with fly ash for generation of ammonia in a batch reactor for flue gas conditioning and nox reduction [texte imprimé] / J.N. Sahu, Auteur ; P. Gangadharan, Auteur ; Anada V. Patwardhan, Auteur . - 2009. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Mots-clés : Catalytic Hydrolysis Résumé : Ammonia is a highly volatile noxious material with adverse physiological effects, which become intolerable even at very low concentrations and present substantial environmental and operating hazards and risk. Yet ammonia has long been known to be used for feedstock of flue gas conditioning and NOx reduction. Urea as the source of ammonia for the production of ammonia has the obvious advantages that no ammonia shipping, handling, and storage is required. The process of this invention minimizes the risks and hazards associated with the transport, storage, and use of anhydrous and aqueous ammonia. Yet no such rapid urea conversion process is available as per requirement of high conversion in shorter time, so here we study the catalytic hydrolysis of urea for fast conversion in a batch reactor. The catalyst used in this study is fly ash, a waste material originating in great amounts in combustion processes. A number of experiments were carried out in a batch reactor at different catalytic doses, temperatures, times, and at a constant concentration of urea solution 10% by weight, and equilibrium and kinetic studies have been made. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801491j

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Flame synthesis of ball-in-shell structured TiO2 nanospheres / Jie Liu in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Titre : Flame synthesis of ball-in-shell structured TiO2 nanospheres Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Yanjie Hu, Auteur ; Feng Gu, Auteur ; Chunzhong Li, Auteur Année de publication : 2009 Note générale : chemical engeneering Langues : Anglais (eng) Mots-clés : Nanosphereselectron microscopy Résumé : Ball-in-shell structured TiO2 nanospheres were successfully made by flame synthesis—a single-step, continuous, and scalable process. The morphology and structure were systematically characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, and N2 sorption. TiO2 nanostructures with good crystalline nature and thermal stability were formed by feeding a titanium tetrachloride and alcohol vapor mixture to a facile diffusion flame. The resultant ball-in-shell spheres were composed of nanocrystallites, with shell thickness and void space width of 30−50 nm and 10−30 nm, respectively. The formation mechanism of ball-in-shell spheres was investigated, depending on the competition between the chemical reaction rate and diffusion rate during the flame process. Furthermore, UV−vis characterization indicates that this structure endows the spheres with higher light absorbance, which may be favorable to design and prepare novel materials with enhanced photocatalytic activities. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800986j [article] Flame synthesis of ball-in-shell structured TiO2 nanospheres [texte imprimé] / Jie Liu, Auteur ; Yanjie Hu, Auteur ; Feng Gu, Auteur ; Chunzhong Li, Auteur . - 2009. chemical engeneering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) Mots-clés : Nanosphereselectron microscopy Résumé : Ball-in-shell structured TiO2 nanospheres were successfully made by flame synthesis—a single-step, continuous, and scalable process. The morphology and structure were systematically characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, and N2 sorption. TiO2 nanostructures with good crystalline nature and thermal stability were formed by feeding a titanium tetrachloride and alcohol vapor mixture to a facile diffusion flame. The resultant ball-in-shell spheres were composed of nanocrystallites, with shell thickness and void space width of 30−50 nm and 10−30 nm, respectively. The formation mechanism of ball-in-shell spheres was investigated, depending on the competition between the chemical reaction rate and diffusion rate during the flame process. Furthermore, UV−vis characterization indicates that this structure endows the spheres with higher light absorbance, which may be favorable to design and prepare novel materials with enhanced photocatalytic activities. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800986j

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Performance changes of surface coated red phosphors with silica nanoparticles and silica nanocomposites / Y. S. Chung in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 740–748 Titre : Performance changes of surface coated red phosphors with silica nanoparticles and silica nanocomposites Type de document : texte imprimé Auteurs : Y. S. Chung, Auteur ; M. Y. Jeon, Auteur Année de publication : 2009 Article en page(s) : p. 740–748 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Phosphors Résumé : To improve the photoluminescence and long-term stability of the Y2O2S:Eu3+ phosphor, surface coatings with silica nanoparticles and poly(methyl methacrylate) (PMMA)-silica nanocomposites were performed via four different techniques. Phosphors were coated with nearly monodispersed silica nanoparticles (5 nm) by a dip-coating method and a sol−gel method (Stöber method). To fabricate the silica nanopariticles used for the phosphor coating, hydrolysis and condensation reactions for the formation of silica nanoparticles, and radical polymerization for the formation of poly(1-vinyl-2-pyrrolidone) were performed simultaneously. Phosphors were coated with PMMA-silica nanocomposites by using two different methods: by reacting silica nanoparticles and methyl methacrylate (MMA) monomer and by reacting mixtures containing MMA and tetraethylorthosilicate. Between these methods, the latter method exhibited the greatest enhancement of photoluminescence and long-term stability of the phosphors. When phosphors were coated with PMMA-silica nanocomposite by the second method, the PL intensity of Y2O2S:Eu3+ was enhanced approximately 5% over that of the uncoated phosphors. In contrast to a decrease in cathode luminescence (CL) intensity with increasing bombardment time for uncoated phosphor, a nearly constant CL intensity was observed for the phosphors coated with PMMA-silica nanocomposite by the latter method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007488 [article] Performance changes of surface coated red phosphors with silica nanoparticles and silica nanocomposites [texte imprimé] / Y. S. Chung, Auteur ; M. Y. Jeon, Auteur . - 2009 . - p. 740–748. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 740–748 Mots-clés : Phosphors Résumé : To improve the photoluminescence and long-term stability of the Y2O2S:Eu3+ phosphor, surface coatings with silica nanoparticles and poly(methyl methacrylate) (PMMA)-silica nanocomposites were performed via four different techniques. Phosphors were coated with nearly monodispersed silica nanoparticles (5 nm) by a dip-coating method and a sol−gel method (Stöber method). To fabricate the silica nanopariticles used for the phosphor coating, hydrolysis and condensation reactions for the formation of silica nanoparticles, and radical polymerization for the formation of poly(1-vinyl-2-pyrrolidone) were performed simultaneously. Phosphors were coated with PMMA-silica nanocomposites by using two different methods: by reacting silica nanoparticles and methyl methacrylate (MMA) monomer and by reacting mixtures containing MMA and tetraethylorthosilicate. Between these methods, the latter method exhibited the greatest enhancement of photoluminescence and long-term stability of the phosphors. When phosphors were coated with PMMA-silica nanocomposite by the second method, the PL intensity of Y2O2S:Eu3+ was enhanced approximately 5% over that of the uncoated phosphors. In contrast to a decrease in cathode luminescence (CL) intensity with increasing bombardment time for uncoated phosphor, a nearly constant CL intensity was observed for the phosphors coated with PMMA-silica nanocomposite by the latter method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007488

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Cationic alkoxylated amine surfactant as a debonding agent for papers made of sulfite-bleached fibers / Pedram Fatehi in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 749–754 Titre : Cationic alkoxylated amine surfactant as a debonding agent for papers made of sulfite-bleached fibers Type de document : texte imprimé Auteurs : Pedram Fatehi, Auteur ; Kevin C. Outhouse, Auteur ; Huining Xiao, Auteur Année de publication : 2009 Article en page(s) : p. 749–754 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Sulfite-Bleached -- Papers Made Résumé : Today, there is a steadily increasing demand for the application of surfactants as debonding agents in tissue manufacturing. The work presented herein focused on evaluating the debonding ability of cationic alkoxylated amine surfactant on unrefined and refined fibers. The results showed that, as the dosage of the surfactant was increased to 10 mg/g on unrefined pulps, the adsorption of the surfactant on the fibers increased to 5 mg/g, and the tensile and burst indices of the papers made of the modified fibers decreased by as much as 12.6% and 14.9%, respectively. Also, the roughness, strain, and moisture content of the papers were enhanced, whereas the apparent density was reduced. Furthermore, the tear index of the papers increased upon the application of surfactant (10 mg/g) at the expense of reductions in tensile and burst indices, as well as the apparent density at any pressure applied in wet pressing. Also, as the pressure was increased, the surfactant impacted the fiber bonding more significantly. On the other hand, the application of surfactant (10 mg/g) somewhat increased the light scattering coefficient of the papers, regardless of the refining load. Furthermore, the adsorption of the surfactant on refined fibers increased with increasing refining load. However, the influence of the surfactant on the tear, tensile, and burst indices and the apparent density was impaired with increasing refining load. Also, the zero-span tensile index and brightness of the papers varied negligibly upon surfactant application. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800929p [article] Cationic alkoxylated amine surfactant as a debonding agent for papers made of sulfite-bleached fibers [texte imprimé] / Pedram Fatehi, Auteur ; Kevin C. Outhouse, Auteur ; Huining Xiao, Auteur . - 2009 . - p. 749–754. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 749–754 Mots-clés : Sulfite-Bleached -- Papers Made Résumé : Today, there is a steadily increasing demand for the application of surfactants as debonding agents in tissue manufacturing. The work presented herein focused on evaluating the debonding ability of cationic alkoxylated amine surfactant on unrefined and refined fibers. The results showed that, as the dosage of the surfactant was increased to 10 mg/g on unrefined pulps, the adsorption of the surfactant on the fibers increased to 5 mg/g, and the tensile and burst indices of the papers made of the modified fibers decreased by as much as 12.6% and 14.9%, respectively. Also, the roughness, strain, and moisture content of the papers were enhanced, whereas the apparent density was reduced. Furthermore, the tear index of the papers increased upon the application of surfactant (10 mg/g) at the expense of reductions in tensile and burst indices, as well as the apparent density at any pressure applied in wet pressing. Also, as the pressure was increased, the surfactant impacted the fiber bonding more significantly. On the other hand, the application of surfactant (10 mg/g) somewhat increased the light scattering coefficient of the papers, regardless of the refining load. Furthermore, the adsorption of the surfactant on refined fibers increased with increasing refining load. However, the influence of the surfactant on the tear, tensile, and burst indices and the apparent density was impaired with increasing refining load. Also, the zero-span tensile index and brightness of the papers varied negligibly upon surfactant application. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800929p

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Controlled fabrication of porous titania beads by a sol−gel templating method / Kai-Feng Du in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 755–762 Titre : Controlled fabrication of porous titania beads by a sol−gel templating method Type de document : texte imprimé Auteurs : Kai-Feng Du, Auteur ; Dong Yang, Auteur ; Yan Sun, Auteur Année de publication : 2009 Article en page(s) : p. 755–762 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Porous titania beads -- Fabrication Résumé : Porous titania beads were synthesized by a sol−gel templating method using agarose gel as template. The morphology and structure of the materials were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and N2 adsorption analysis, etc. It was found that the size and pore structure of the resultant titania beads could be readily controlled by using various sized templates and by changing the precipitation conditions. Under optimized conditions (i.e., impregnating agarose gel into titanium precursors for 6 h, three cycles of repeated impregnation and hydrolyzing process, and calcination at 450 °C), porous titania beads of 7−150 μm in mean diameters were fabricated by using different sized agarose beads as templates. The beads displayed perfect spherical shape, with an average pore size of 6 nm and specific surface area of 69.9 m2 g−1. The titania beads of 15 μm in average diameter were further characterized for application as liquid chromatographic packings. Flow hydrodynamic experiment indicated that they possessed high mechanical strength to withstand a pressure drop up to 12 MPa. The column efficiency reached 6165 plates m−1 for acetone and 4650 plates m−1 for N,N-dimethylaniline under nonretained condition. Moreover, baseline separation of three aniline derivatives featuring only small structural differences was realized by using this packed column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011165 [article] Controlled fabrication of porous titania beads by a sol−gel templating method [texte imprimé] / Kai-Feng Du, Auteur ; Dong Yang, Auteur ; Yan Sun, Auteur . - 2009 . - p. 755–762. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 755–762 Mots-clés : Porous titania beads -- Fabrication Résumé : Porous titania beads were synthesized by a sol−gel templating method using agarose gel as template. The morphology and structure of the materials were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and N2 adsorption analysis, etc. It was found that the size and pore structure of the resultant titania beads could be readily controlled by using various sized templates and by changing the precipitation conditions. Under optimized conditions (i.e., impregnating agarose gel into titanium precursors for 6 h, three cycles of repeated impregnation and hydrolyzing process, and calcination at 450 °C), porous titania beads of 7−150 μm in mean diameters were fabricated by using different sized agarose beads as templates. The beads displayed perfect spherical shape, with an average pore size of 6 nm and specific surface area of 69.9 m2 g−1. The titania beads of 15 μm in average diameter were further characterized for application as liquid chromatographic packings. Flow hydrodynamic experiment indicated that they possessed high mechanical strength to withstand a pressure drop up to 12 MPa. The column efficiency reached 6165 plates m−1 for acetone and 4650 plates m−1 for N,N-dimethylaniline under nonretained condition. Moreover, baseline separation of three aniline derivatives featuring only small structural differences was realized by using this packed column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011165

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Synthesis and characterization of magnesium hydroxide using a bvubbling setup / X. Li in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 763–768 Titre : Synthesis and characterization of magnesium hydroxide using a bvubbling setup Type de document : texte imprimé Auteurs : X. Li, Auteur ; G. B. Ma, Auteur ; Y. Y. Liu, Auteur Année de publication : 2009 Article en page(s) : p. 763–768 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Magnesium -- Hydroxide -Synthesis --Characterization Résumé : Magnesium hydroxide [MH] with porous nanoplates were synthesized from boric magnesium fertilizer (MgSO4·7H2O), using a large bubbling setup designed by the authors. The regular hexagonal plates of MH with a smaller specific area were formed after hydrothermal treatment. The effects of various operating variables, including the ammonia flow rate, reaction temperature, magnesium source, particle sizes, and dispersion properties of the synthesis products were investigated. X-ray diffraction, scanning electron microscopy, laser particle size analyzer, and thermogravimetric analyzer have been employed to characterize these products. The results showed that the mean particle size (D50) of the MH was about 2 μm, and products were loose enough for filtering. The diffraction intensity of the (001) direction was higher than the (101) direction. The Mg2+ conversion in the continuous setup reached 95% and the decomposition temperature of products was 370 °C. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801306f [article] Synthesis and characterization of magnesium hydroxide using a bvubbling setup [texte imprimé] / X. Li, Auteur ; G. B. Ma, Auteur ; Y. Y. Liu, Auteur . - 2009 . - p. 763–768. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 763–768 Mots-clés : Magnesium -- Hydroxide -Synthesis --Characterization Résumé : Magnesium hydroxide [MH] with porous nanoplates were synthesized from boric magnesium fertilizer (MgSO4·7H2O), using a large bubbling setup designed by the authors. The regular hexagonal plates of MH with a smaller specific area were formed after hydrothermal treatment. The effects of various operating variables, including the ammonia flow rate, reaction temperature, magnesium source, particle sizes, and dispersion properties of the synthesis products were investigated. X-ray diffraction, scanning electron microscopy, laser particle size analyzer, and thermogravimetric analyzer have been employed to characterize these products. The results showed that the mean particle size (D50) of the MH was about 2 μm, and products were loose enough for filtering. The diffraction intensity of the (001) direction was higher than the (101) direction. The Mg2+ conversion in the continuous setup reached 95% and the decomposition temperature of products was 370 °C. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801306f

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Chitin microstructure formation by rapid expansion techniques with supercritical carbon dioxide / Ricardo Salinas-Hernández in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 769–778 Titre : Chitin microstructure formation by rapid expansion techniques with supercritical carbon dioxide Type de document : texte imprimé Auteurs : Ricardo Salinas-Hernández, Auteur ; F. Alberto Ruiz-Trevino, Auteur ; Ciro H. Ortiz-Estrada, Auteur Année de publication : 2009 Article en page(s) : p. 769–778 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Carbon Dioxide Résumé : Rapid expansion techniques (of supercritical solution (RESS) and into a liquid solvent (RESOLV)) with supercritical carbon dioxide are used to form chitin microstructures. The effect of the pre-expansion conditions, temperature (40−60 °C), pressure (104−208 bar), chitin concentration (1−6 mg/mL), and nozzle diameter (100−500 μm), on the morphology and the size of the chitin microstructures formed with both RESS and RESOLV are studied. Depending on the experimental conditions, it is found that spherical microparticles, with average diameters of 1.7−5.3 μm, are obtained with RESS, while continuous microfibers, with average diameters of 11.5−19.3 μm, are obtained with RESOLV. For both RESS and RESOLV it was observed that the pre-expansion temperature−pressure conditions studied here have practically no effect on the average diameters of the formed material. On the contrary, it is shown that concentration and nozzle diameter directly influence the morphology and size obtaining that lower concentrations and smaller diameter nozzles lead to the production of smaller diameter microstructures and closed-size distributions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800084x [article] Chitin microstructure formation by rapid expansion techniques with supercritical carbon dioxide [texte imprimé] / Ricardo Salinas-Hernández, Auteur ; F. Alberto Ruiz-Trevino, Auteur ; Ciro H. Ortiz-Estrada, Auteur . - 2009 . - p. 769–778. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 769–778 Mots-clés : Carbon Dioxide Résumé : Rapid expansion techniques (of supercritical solution (RESS) and into a liquid solvent (RESOLV)) with supercritical carbon dioxide are used to form chitin microstructures. The effect of the pre-expansion conditions, temperature (40−60 °C), pressure (104−208 bar), chitin concentration (1−6 mg/mL), and nozzle diameter (100−500 μm), on the morphology and the size of the chitin microstructures formed with both RESS and RESOLV are studied. Depending on the experimental conditions, it is found that spherical microparticles, with average diameters of 1.7−5.3 μm, are obtained with RESS, while continuous microfibers, with average diameters of 11.5−19.3 μm, are obtained with RESOLV. For both RESS and RESOLV it was observed that the pre-expansion temperature−pressure conditions studied here have practically no effect on the average diameters of the formed material. On the contrary, it is shown that concentration and nozzle diameter directly influence the morphology and size obtaining that lower concentrations and smaller diameter nozzles lead to the production of smaller diameter microstructures and closed-size distributions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800084x

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Chlorination of titanium oxycarbonitride produced by carbothermal nitridation of rutile / Andrew Adipuri in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 779–787 Titre : Chlorination of titanium oxycarbonitride produced by carbothermal nitridation of rutile Type de document : texte imprimé Auteurs : Andrew Adipuri, Auteur ; Guangqing Zhang, Auteur ; Oleg Ostrovski, Auteur Année de publication : 2009 Article en page(s) : p. 779–787 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Titanium oxycarbonitride Résumé : Titanium oxycarbonitride was produced by carbothermal nitridation of rutile. Mixtures consisting of titania and graphite with different carbon to titanium dioxide molar ratios were pressed into pellets and subsequently heated under nitrogen atmosphere at 1450 °C. Titanium oxycarbonitride was chlorinated in a horizontal tube furnace using chlorine and Cl2−N2 gas mixture. Effects of furnace temperature, chlorine partial pressure, gas flow rate, and particle size on the rate and extent of chlorination were examined. The chlorination was ignited at 150−200 °C. Chlorine partial pressure in Cl2−N2 gas mixture, gas flow rate, and particle size affected the chlorination rate, while the effect of particle size was insignificant. Extent of chlorination of titanium oxycarbonitride produced with carbon-to-titania molar ratio at 2.5 was close to 100% after 40 min of reaction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801160w [article] Chlorination of titanium oxycarbonitride produced by carbothermal nitridation of rutile [texte imprimé] / Andrew Adipuri, Auteur ; Guangqing Zhang, Auteur ; Oleg Ostrovski, Auteur . - 2009 . - p. 779–787. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 779–787 Mots-clés : Titanium oxycarbonitride Résumé : Titanium oxycarbonitride was produced by carbothermal nitridation of rutile. Mixtures consisting of titania and graphite with different carbon to titanium dioxide molar ratios were pressed into pellets and subsequently heated under nitrogen atmosphere at 1450 °C. Titanium oxycarbonitride was chlorinated in a horizontal tube furnace using chlorine and Cl2−N2 gas mixture. Effects of furnace temperature, chlorine partial pressure, gas flow rate, and particle size on the rate and extent of chlorination were examined. The chlorination was ignited at 150−200 °C. Chlorine partial pressure in Cl2−N2 gas mixture, gas flow rate, and particle size affected the chlorination rate, while the effect of particle size was insignificant. Extent of chlorination of titanium oxycarbonitride produced with carbon-to-titania molar ratio at 2.5 was close to 100% after 40 min of reaction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801160w

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Synthesis and properties of thermoplastic poly(vinyl alcohol)-graft-lactic acid copolymers / Jing Ding in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 788–793 Titre : Synthesis and properties of thermoplastic poly(vinyl alcohol)-graft-lactic acid copolymers Type de document : texte imprimé Auteurs : Jing Ding, Auteur ; Si - Chong Chen, Auteur ; Xiu-Li Wang, Auteur ; Yu-Zhong Wang, Auteur Année de publication : 2009 Article en page(s) : p. 788–793 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Thermoplastic Poly --Properties Résumé : Poly(vinyl alcohol)-graft-lactic acid (PVA-g-LA) was synthesized by melt polycondensation of PVA and lactic acid using stannous chloride as a catalyst. The molecular structure of the copolymer was characterized by 1H NMR. The thermal properties of PVA-g-LA were investigated by differential scanning calorimetry and thermogravimetric analysis. The results showed that the PVA-g-LA copolymer exhibited lower glass transition temperature (Tg) and melting temperature (Tm) and higher decomposition temperature (Td) than pure PVA, and a difference of 60−80 °C between Tm and Td could be obtained, suggesting that the introduction of the oligo-poly(lactic acid) grafted chains can give rise to the melting flow processing of PVA. PVA-g-LA films prepared by compression molding at 140−150 °C had good flexibility and elasticity as well as water resistance. The copolymers have a potential application in food packaging. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013428 [article] Synthesis and properties of thermoplastic poly(vinyl alcohol)-graft-lactic acid copolymers [texte imprimé] / Jing Ding, Auteur ; Si - Chong Chen, Auteur ; Xiu-Li Wang, Auteur ; Yu-Zhong Wang, Auteur . - 2009 . - p. 788–793. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 788–793 Mots-clés : Thermoplastic Poly --Properties Résumé : Poly(vinyl alcohol)-graft-lactic acid (PVA-g-LA) was synthesized by melt polycondensation of PVA and lactic acid using stannous chloride as a catalyst. The molecular structure of the copolymer was characterized by 1H NMR. The thermal properties of PVA-g-LA were investigated by differential scanning calorimetry and thermogravimetric analysis. The results showed that the PVA-g-LA copolymer exhibited lower glass transition temperature (Tg) and melting temperature (Tm) and higher decomposition temperature (Td) than pure PVA, and a difference of 60−80 °C between Tm and Td could be obtained, suggesting that the introduction of the oligo-poly(lactic acid) grafted chains can give rise to the melting flow processing of PVA. PVA-g-LA films prepared by compression molding at 140−150 °C had good flexibility and elasticity as well as water resistance. The copolymers have a potential application in food packaging. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013428

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Optimal gas-to-liquid product selection from natural gas under uncertain price scenarios / Chul-Jin Lee in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 794–800 Titre : Optimal gas-to-liquid product selection from natural gas under uncertain price scenarios Type de document : texte imprimé Auteurs : Chul-Jin Lee, Auteur ; Youngsub Lim, Auteur ; Ho Soo Kim, Auteur ; Chonghun Han, Auteur Année de publication : 2009 Article en page(s) : p. 794–800 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Optimal Gas Résumé : Gas-to-liquid (GTL) products have come into the spotlight for alternative energy carriers as an environmentally benign and highly profitable alternative to petroleum resources. There have been various studies conducted to explore the economic and environmental benefits of individual GTL products, but few researchers have performed a comparative economic assessment, determining which product would make the greatest profit among various GTL products. Furthermore, considering the inherent characteristics of process industries, profits from one product are deeply dependent on the price of its raw material. Thus, it is important to choose an optimal GTL product covering those price variations. In this study, we performed economic analyses for three GTL products used for transportation fuel through process modeling and investigated the profitability according to variations in feedstock cost and product price. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800879y [article] Optimal gas-to-liquid product selection from natural gas under uncertain price scenarios [texte imprimé] / Chul-Jin Lee, Auteur ; Youngsub Lim, Auteur ; Ho Soo Kim, Auteur ; Chonghun Han, Auteur . - 2009 . - p. 794–800. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 794–800 Mots-clés : Optimal Gas Résumé : Gas-to-liquid (GTL) products have come into the spotlight for alternative energy carriers as an environmentally benign and highly profitable alternative to petroleum resources. There have been various studies conducted to explore the economic and environmental benefits of individual GTL products, but few researchers have performed a comparative economic assessment, determining which product would make the greatest profit among various GTL products. Furthermore, considering the inherent characteristics of process industries, profits from one product are deeply dependent on the price of its raw material. Thus, it is important to choose an optimal GTL product covering those price variations. In this study, we performed economic analyses for three GTL products used for transportation fuel through process modeling and investigated the profitability according to variations in feedstock cost and product price. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800879y

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Application of robust control tools to the simultaneous design and control of dynamic systems / Luis A. Ricardez-Sandoval in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 801–813 Titre : Application of robust control tools to the simultaneous design and control of dynamic systems Type de document : texte imprimé Auteurs : Luis A. Ricardez-Sandoval, Auteur ; Hector M. Budman, Auteur Année de publication : 2009 Article en page(s) : p. 801–813 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Dynamic--Control Résumé : This paper presents a new approach to integrate process design and control. Robust stability and performance measures based on Lyapunov theory and structured singular value analysis (SSV) are used to estimate bounds on process worst-case variability, process feasibility, and process stability. In this approach, the simultaneous design and control problem is posed as a nonlinear constrained optimization problem. The proposed methodology is illustrated using the design of a mixing tank process. The resulting design was compared to the design using a dynamic optimization approach. The expected computational burden required by this method for the design of large-scale processes is also estimated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800378y [article] Application of robust control tools to the simultaneous design and control of dynamic systems [texte imprimé] / Luis A. Ricardez-Sandoval, Auteur ; Hector M. Budman, Auteur . - 2009 . - p. 801–813. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 801–813 Mots-clés : Dynamic--Control Résumé : This paper presents a new approach to integrate process design and control. Robust stability and performance measures based on Lyapunov theory and structured singular value analysis (SSV) are used to estimate bounds on process worst-case variability, process feasibility, and process stability. In this approach, the simultaneous design and control problem is posed as a nonlinear constrained optimization problem. The proposed methodology is illustrated using the design of a mixing tank process. The resulting design was compared to the design using a dynamic optimization approach. The expected computational burden required by this method for the design of large-scale processes is also estimated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800378y

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Multisite refinery and petrochemical network design / K. Al-Qahtani in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 814–826 Titre : Multisite refinery and petrochemical network design : optimal integration and coordination Type de document : texte imprimé Auteurs : K. Al-Qahtani, Auteur ; Ali Elkamel, Auteur Année de publication : 2009 Article en page(s) : p. 814–826 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Petrochemical Network Design: Résumé : This paper addresses the design of optimal integration and coordination of a refinery and petrochemical network to satisfy given chemical products demand. The refinery and petrochemical systems were modeled as a mixed-integer problem with the objective of minimizing the annualized cost over a given time horizon among the refineries and maximizing the added value of the petrochemical network. The main feature of the paper is the development of a methodology for simultaneous analysis of process network integration within a multisite refinery and petrochemical system. This approach provides appropriate planning across the petroleum refining and petrochemical industry and achieves an optimal production strategy by allowing appropriate trade-offs between the refinery and the downstream petrochemical markets. The performance of the proposed model was tested on industrial-scale examples of multiple refineries and a poly(vinyl chloride) (PVC) complex to illustrate the economic potential and trade-offs involved in the optimization of the network. The proposed methodology not only devises the integration network in the refineries and synthesizes the petrochemical industry, but also provides refinery expansion requirements, production levels, and blending levels. The use of mathematical programming on an enterprise-wide scale to address strategic decisions considering various process integration alternatives yields substantial benefits. These benefits of process integration materialize in terms of economic considerations and improvements in the understanding of the process interactions and systems limitations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801001q [article] Multisite refinery and petrochemical network design : optimal integration and coordination [texte imprimé] / K. Al-Qahtani, Auteur ; Ali Elkamel, Auteur . - 2009 . - p. 814–826. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 814–826 Mots-clés : Petrochemical Network Design: Résumé : This paper addresses the design of optimal integration and coordination of a refinery and petrochemical network to satisfy given chemical products demand. The refinery and petrochemical systems were modeled as a mixed-integer problem with the objective of minimizing the annualized cost over a given time horizon among the refineries and maximizing the added value of the petrochemical network. The main feature of the paper is the development of a methodology for simultaneous analysis of process network integration within a multisite refinery and petrochemical system. This approach provides appropriate planning across the petroleum refining and petrochemical industry and achieves an optimal production strategy by allowing appropriate trade-offs between the refinery and the downstream petrochemical markets. The performance of the proposed model was tested on industrial-scale examples of multiple refineries and a poly(vinyl chloride) (PVC) complex to illustrate the economic potential and trade-offs involved in the optimization of the network. The proposed methodology not only devises the integration network in the refineries and synthesizes the petrochemical industry, but also provides refinery expansion requirements, production levels, and blending levels. The use of mathematical programming on an enterprise-wide scale to address strategic decisions considering various process integration alternatives yields substantial benefits. These benefits of process integration materialize in terms of economic considerations and improvements in the understanding of the process interactions and systems limitations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801001q

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Rough set-based fuzzy rule acquisition and Its application for fault diagnosis in petrochemical process / Zhiqiang Geng in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 827–836 Titre : Rough set-based fuzzy rule acquisition and Its application for fault diagnosis in petrochemical process Type de document : texte imprimé Auteurs : Zhiqiang Geng, Auteur ; Qunxiong Zhu, Auteur Année de publication : 2009 Article en page(s) : p 827–836 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Petrochemical Process Résumé : Data mining techniques can discover experience, knowledge, and operational rules from a large industrial data set to recognize process abnormal situations or faults, further improve production-level, and optimize operational conditions. In this paper, a rough set-based fuzzy rule acquisition approach and a fault diagnosis scheme of industrial process are studied in detail. A new heuristic reduct algorithm is proposed to obtain the optimum reduction set of decision information system. Moreover, a fuzzy discretization model for continuous data based on normal distribution of process variables is put forward to overcome the subjective of selecting fuzzy membership functions and decrease the sensitivity to noise signals. Furthermore, the proposed data mining algorithm and fault diagnosis scheme are applied into a petrochemical process. The validity of the proposed strategy is verified by application of a practical ethylene cracking furnace system, which can discover abnormal process situations and improve plant safety in petrochemical industry. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071171g [article] Rough set-based fuzzy rule acquisition and Its application for fault diagnosis in petrochemical process [texte imprimé] / Zhiqiang Geng, Auteur ; Qunxiong Zhu, Auteur . - 2009 . - p 827–836. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 827–836 Mots-clés : Petrochemical Process Résumé : Data mining techniques can discover experience, knowledge, and operational rules from a large industrial data set to recognize process abnormal situations or faults, further improve production-level, and optimize operational conditions. In this paper, a rough set-based fuzzy rule acquisition approach and a fault diagnosis scheme of industrial process are studied in detail. A new heuristic reduct algorithm is proposed to obtain the optimum reduction set of decision information system. Moreover, a fuzzy discretization model for continuous data based on normal distribution of process variables is put forward to overcome the subjective of selecting fuzzy membership functions and decrease the sensitivity to noise signals. Furthermore, the proposed data mining algorithm and fault diagnosis scheme are applied into a petrochemical process. The validity of the proposed strategy is verified by application of a practical ethylene cracking furnace system, which can discover abnormal process situations and improve plant safety in petrochemical industry. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071171g

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Two-dimensional dynamic principal component analysis with autodetermined support region / Yuan Yao in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.837–843 Titre : Two-dimensional dynamic principal component analysis with autodetermined support region Type de document : texte imprimé Auteurs : Yuan Yao, Auteur ; Yinghu Diao, Auteur ; Ningyun Lu, Auteur ; Junde Lu, Auteur ; Furong Gao, Auteur Année de publication : 2009 Article en page(s) : p.837–843 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Dynamics--Principal Component Analysis Résumé : Dynamics are inherent characteristics of batch processes. In some cases, such dynamics exist not only within a particular batch, but also from batch to batch. In previous work, two-dimensional dynamic principal component analysis (2-D-DPCA) has been developed to monitor 2-D dynamics. Support region determination is a key step in 2-D-DPCA modeling and monitoring of a batch process. A proper support region can ensure modeling accuracy, monitoring efficiency, and reasonable fault diagnosis. In this work, an automatic method for support region determination is developed. This data-based method can be applied on different batch processes without prior process knowledge. Simulation shows that the developed method has good application potentials for both monitoring and fault diagnosis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800825m [article] Two-dimensional dynamic principal component analysis with autodetermined support region [texte imprimé] / Yuan Yao, Auteur ; Yinghu Diao, Auteur ; Ningyun Lu, Auteur ; Junde Lu, Auteur ; Furong Gao, Auteur . - 2009 . - p.837–843. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.837–843 Mots-clés : Dynamics--Principal Component Analysis Résumé : Dynamics are inherent characteristics of batch processes. In some cases, such dynamics exist not only within a particular batch, but also from batch to batch. In previous work, two-dimensional dynamic principal component analysis (2-D-DPCA) has been developed to monitor 2-D dynamics. Support region determination is a key step in 2-D-DPCA modeling and monitoring of a batch process. A proper support region can ensure modeling accuracy, monitoring efficiency, and reasonable fault diagnosis. In this work, an automatic method for support region determination is developed. This data-based method can be applied on different batch processes without prior process knowledge. Simulation shows that the developed method has good application potentials for both monitoring and fault diagnosis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800825m

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Artificial neural network and grid search aided optimization of temperature profile of temperature gradient reactor for dimethyl ether synthesis from syngas / Kohji Omata in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 844–849 Titre : Artificial neural network and grid search aided optimization of temperature profile of temperature gradient reactor for dimethyl ether synthesis from syngas Type de document : texte imprimé Auteurs : Kohji Omata, Auteur ; Masahiko Hashimoto Sutarto, Auteur ; Yamada, Muneyoshi, Auteur Année de publication : 2009 Article en page(s) : p. 844–849 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : temperature gradient reactor Résumé : The temperature setting of a fixed bed reactor with a temperature gradient (TGR, temperature gradient reactor) was optimized using an artificial neural network (ANN) and grid search to attain high one-pass CO conversion for one-step dimethyl ether (DME) synthesis from syngas (3CO + 3H2 → DME + CO2). In the TGR, the catalyst bed was divided into 5 zones in series, and the temperature of each zone was optimized. Experiments were designed using an orthogonal array, and the experimental result was used for training the ANN to correlate the temperature setting and CO conversion. A grid search on the trained ANN was applied to find the optimum temperature setting. TGR was effective in overcoming both the equilibrium limit of the reaction at high temperature and the low activity of the catalyst at low temperature. To attain high CO conversion, Cu−Zn−Al−Ti−Nb−V−Cr catalysts with the optimized composition for each reaction temperature and γ-alumina were packed into the 5 zones of the TGR. As a result, a high one-pass conversion of CO at 82% was attained at 1 MPa, W/F = 50 g-cat·h/mol by means of the combination of the optimum catalyst and TGR. The CO conversion is much higher in comparison to the 72% found in TGR with a standard Cu catalyst, and to 69.5% in the isothermal reactor at 523K with a standard Cu catalyst. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008633 [article] Artificial neural network and grid search aided optimization of temperature profile of temperature gradient reactor for dimethyl ether synthesis from syngas [texte imprimé] / Kohji Omata, Auteur ; Masahiko Hashimoto Sutarto, Auteur ; Yamada, Muneyoshi, Auteur . - 2009 . - p. 844–849. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 844–849 Mots-clés : temperature gradient reactor Résumé : The temperature setting of a fixed bed reactor with a temperature gradient (TGR, temperature gradient reactor) was optimized using an artificial neural network (ANN) and grid search to attain high one-pass CO conversion for one-step dimethyl ether (DME) synthesis from syngas (3CO + 3H2 → DME + CO2). In the TGR, the catalyst bed was divided into 5 zones in series, and the temperature of each zone was optimized. Experiments were designed using an orthogonal array, and the experimental result was used for training the ANN to correlate the temperature setting and CO conversion. A grid search on the trained ANN was applied to find the optimum temperature setting. TGR was effective in overcoming both the equilibrium limit of the reaction at high temperature and the low activity of the catalyst at low temperature. To attain high CO conversion, Cu−Zn−Al−Ti−Nb−V−Cr catalysts with the optimized composition for each reaction temperature and γ-alumina were packed into the 5 zones of the TGR. As a result, a high one-pass conversion of CO at 82% was attained at 1 MPa, W/F = 50 g-cat·h/mol by means of the combination of the optimum catalyst and TGR. The CO conversion is much higher in comparison to the 72% found in TGR with a standard Cu catalyst, and to 69.5% in the isothermal reactor at 523K with a standard Cu catalyst. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008633

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Rapid In Situ Transesterification of Sunflower Oil / Jianli Zeng in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 850–856 Titre : Rapid In Situ Transesterification of Sunflower Oil Type de document : texte imprimé Auteurs : Jianli Zeng, Auteur ; Xiaodong Wang, Auteur ; Bing Zhao, Auteur ; Jingcan Sun, Auteur ; Yuchun Wang, Auteur Année de publication : 2009 Article en page(s) : p. 850–856 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Sunflower Oil-- Transesterification Résumé : A rapid in situ transesterification process of sunflower oil with methanol assisted by diethoxymethane (DEM) is described in this article. DEM served as both extraction solvent and reaction promoter in the process. The effects of moisture content of sunflower seeds, catalyst category, molar ratio of catalyst/oil, molar ratio of methanol/oil, molar ratio of DEM/oil, reaction time, reaction temperature, and agitation speed on the in situ transesterification were investigated. The most important factors which influenced the crude biodiesel yield, free fatty acid (FFA) content, and fatty acid methyl ester (FAME) purity were the molar ratio of DEM/oil, molar ratio of catalyst/oil, and molar ratio of catalyst/oil, respectively. An empirical model of the rapid in situ transesterification process was established and used to determine the optimal reaction conditions. When the in situ transesterification was carried out at the molar ratio of catalyst/oil of 0.5:1, the molar ratio of methanol/oil of 101.39:1, the molar ratio of DEM/oil of 57.85:1, the agitation speed of 150 rpm, and reaction temperature of 20 °C, a product containing 97.7% FAME and 0.74% FFA was obtained within 13 min. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008956 [article] Rapid In Situ Transesterification of Sunflower Oil [texte imprimé] / Jianli Zeng, Auteur ; Xiaodong Wang, Auteur ; Bing Zhao, Auteur ; Jingcan Sun, Auteur ; Yuchun Wang, Auteur . - 2009 . - p. 850–856. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 850–856 Mots-clés : Sunflower Oil-- Transesterification Résumé : A rapid in situ transesterification process of sunflower oil with methanol assisted by diethoxymethane (DEM) is described in this article. DEM served as both extraction solvent and reaction promoter in the process. The effects of moisture content of sunflower seeds, catalyst category, molar ratio of catalyst/oil, molar ratio of methanol/oil, molar ratio of DEM/oil, reaction time, reaction temperature, and agitation speed on the in situ transesterification were investigated. The most important factors which influenced the crude biodiesel yield, free fatty acid (FFA) content, and fatty acid methyl ester (FAME) purity were the molar ratio of DEM/oil, molar ratio of catalyst/oil, and molar ratio of catalyst/oil, respectively. An empirical model of the rapid in situ transesterification process was established and used to determine the optimal reaction conditions. When the in situ transesterification was carried out at the molar ratio of catalyst/oil of 0.5:1, the molar ratio of methanol/oil of 101.39:1, the molar ratio of DEM/oil of 57.85:1, the agitation speed of 150 rpm, and reaction temperature of 20 °C, a product containing 97.7% FAME and 0.74% FFA was obtained within 13 min. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008956

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Incorporating tangent pinch points into the conceptual modeling of batch distillations / Karina Andrea Torres in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.857–869 Titre : Incorporating tangent pinch points into the conceptual modeling of batch distillations : ternary mixtures Type de document : texte imprimé Auteurs : Karina Andrea Torres, Auteur ; Jose Espinosa, Auteur Année de publication : 2009 Article en page(s) : p.857–869 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Tangent Pinch Points--incorporating Résumé : This contribution explores the influence of tangent pinch points on the performance of batch distillations of highly nonideal ternary mixtures and its incorporation into a conceptual modeling framework under the assumption of a rectifier with an infinite number of stages. The maximum feasible distillate composition on the line of preferred separation and its corresponding limiting reflux ratio are first determined with the aid of bifurcation analysis of reversible distillation profiles. Then, the dependence of feasible distillate mole fractions on reflux ratios above the limiting one is calculated by solving a nonlinear equation system, which incorporates the tangency condition. Results obtained from the conceptual model for instantaneous column performance are in excellent agreement with those calculated from rigorous simulation. Two highly nonideal ternary mixtures are studied. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801169x [article] Incorporating tangent pinch points into the conceptual modeling of batch distillations : ternary mixtures [texte imprimé] / Karina Andrea Torres, Auteur ; Jose Espinosa, Auteur . - 2009 . - p.857–869. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.857–869 Mots-clés : Tangent Pinch Points--incorporating Résumé : This contribution explores the influence of tangent pinch points on the performance of batch distillations of highly nonideal ternary mixtures and its incorporation into a conceptual modeling framework under the assumption of a rectifier with an infinite number of stages. The maximum feasible distillate composition on the line of preferred separation and its corresponding limiting reflux ratio are first determined with the aid of bifurcation analysis of reversible distillation profiles. Then, the dependence of feasible distillate mole fractions on reflux ratios above the limiting one is calculated by solving a nonlinear equation system, which incorporates the tangency condition. Results obtained from the conceptual model for instantaneous column performance are in excellent agreement with those calculated from rigorous simulation. Two highly nonideal ternary mixtures are studied. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801169x

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Adsorption of ga(III) on oxidized coir / Umesh Suryavanshi in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 870–876 Titre : Adsorption of ga(III) on oxidized coir Type de document : texte imprimé Auteurs : Umesh Suryavanshi, Auteur ; Sanjeev R. Shukla, Auteur Année de publication : 2009 Article en page(s) : p. 870–876 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Processing Technology Résumé : Gallium is a strategic material due to its high-tech applications, but its availability in minerals is extremely poor to ensure economically feasible recovery. It is possible through the processing of other Ga-containing minerals, during which Ga gets concentrated. In the present work, Batch-wise adsorption of Ga(III) from the aqueous solution of gallium nitrate having different concentrations was attempted on unmodified (UC) and oxidized coir (OC). The SEM micrographs of OC show more porous structure due to the removal of pits from the coir surface by oxidation, leading to a 1.5× increase in the surface area. The effect of increasing pH from 1 to 3 greatly enhanced the adsorption. At pH 3, as high as a 70.53% adsorption was achieved on OC, beyond which Ga does not remain in solution form. Ga(III), being a trivalent ion, possesses substantial acidity, which increases with its concentration. The mechanism of Ga(III) adsorption on UC and OC has been put forward based on ion exchange. The adsorption fits to the Langmuir isotherm model and has been shown to obey pseudo second order kinetics. Considerably high adsorption capacity is gained by the coir upon simple oxidation treatment. The maximum adsorption capacity of OC was observed to be 19.42 mg g−1, as compared to 13.75 mg g−1 for UC. Desorption using 0.5 M HCl leads to nearly complete recovery of Ga(III) without affecting the physical characteristics of the adsorbent, like strength and crystallinity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801259c [article] Adsorption of ga(III) on oxidized coir [texte imprimé] / Umesh Suryavanshi, Auteur ; Sanjeev R. Shukla, Auteur . - 2009 . - p. 870–876. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 870–876 Mots-clés : Processing Technology Résumé : Gallium is a strategic material due to its high-tech applications, but its availability in minerals is extremely poor to ensure economically feasible recovery. It is possible through the processing of other Ga-containing minerals, during which Ga gets concentrated. In the present work, Batch-wise adsorption of Ga(III) from the aqueous solution of gallium nitrate having different concentrations was attempted on unmodified (UC) and oxidized coir (OC). The SEM micrographs of OC show more porous structure due to the removal of pits from the coir surface by oxidation, leading to a 1.5× increase in the surface area. The effect of increasing pH from 1 to 3 greatly enhanced the adsorption. At pH 3, as high as a 70.53% adsorption was achieved on OC, beyond which Ga does not remain in solution form. Ga(III), being a trivalent ion, possesses substantial acidity, which increases with its concentration. The mechanism of Ga(III) adsorption on UC and OC has been put forward based on ion exchange. The adsorption fits to the Langmuir isotherm model and has been shown to obey pseudo second order kinetics. Considerably high adsorption capacity is gained by the coir upon simple oxidation treatment. The maximum adsorption capacity of OC was observed to be 19.42 mg g−1, as compared to 13.75 mg g−1 for UC. Desorption using 0.5 M HCl leads to nearly complete recovery of Ga(III) without affecting the physical characteristics of the adsorbent, like strength and crystallinity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801259c

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Influence of particle size, applied compression, and substratum material on particle-surface adhesion force using the centrifuge technique / Marcos A Felicetti in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.877–887 Titre : Influence of particle size, applied compression, and substratum material on particle-surface adhesion force using the centrifuge technique Type de document : texte imprimé Auteurs : Marcos A Felicetti, Auteur ; Giancarlo R Salazar-Banda, Auteur ; José R Coury, Auteur ; Mônica L Aguiar, Auteur Année de publication : 2009 Article en page(s) : p.877–887 Note générale : chemical enginneering Langues : Anglais (eng) Mots-clés : centrifuge technique Résumé : The centrifuge technique was used to investigate the influence of particle size, applied compression, and substrate material (stainless steel, glass, Teflon, and poly(vinyl chloride)) on particle−surface adhesion force. For this purpose, phosphatic rock (ρp = 3090 kg/m3) and manioc starch particles (ρp = 1480 kg/m3) were used as test particles. A microcentrifuge that reached a maximum rotation speed of 14 000 rpm and which contained specially designed centrifuge tubes was used in the adhesion force measurements. The curves showed that the adhesion force profile followed a normal log distribution. The adhesion force increased linearly with particle size and with the increase of each increment of compression force. The manioc starch particles presented greater adhesion forces than the phosphatic rock particles for all particle sizes studied. The glass substrate showed a higher adherence than the other materials, probably due to its smoother topographic surface roughness in relation to the other substrata. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071506u [article] Influence of particle size, applied compression, and substratum material on particle-surface adhesion force using the centrifuge technique [texte imprimé] / Marcos A Felicetti, Auteur ; Giancarlo R Salazar-Banda, Auteur ; José R Coury, Auteur ; Mônica L Aguiar, Auteur . - 2009 . - p.877–887. chemical enginneering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.877–887 Mots-clés : centrifuge technique Résumé : The centrifuge technique was used to investigate the influence of particle size, applied compression, and substrate material (stainless steel, glass, Teflon, and poly(vinyl chloride)) on particle−surface adhesion force. For this purpose, phosphatic rock (ρp = 3090 kg/m3) and manioc starch particles (ρp = 1480 kg/m3) were used as test particles. A microcentrifuge that reached a maximum rotation speed of 14 000 rpm and which contained specially designed centrifuge tubes was used in the adhesion force measurements. The curves showed that the adhesion force profile followed a normal log distribution. The adhesion force increased linearly with particle size and with the increase of each increment of compression force. The manioc starch particles presented greater adhesion forces than the phosphatic rock particles for all particle sizes studied. The glass substrate showed a higher adherence than the other materials, probably due to its smoother topographic surface roughness in relation to the other substrata. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071506u

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Extraction of acrylic, propionic, and butyric Acid using aliquat 336 in oleyl alcohol / Amit Keshav in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.888–893 Titre : Extraction of acrylic, propionic, and butyric Acid using aliquat 336 in oleyl alcohol : equilibria and effect of temperature Type de document : texte imprimé Auteurs : Amit Keshav, Auteur ; Kailas L. Wasewar, Auteur ; Shri Chand, Auteur Année de publication : 2009 Article en page(s) : p.888–893 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Acrylic--Propionic--Butyric Acid Résumé : Reactive extractions of acrylic, propionic, and butyric acids using Aliquat 336 in oleyl alcohol were carried out to study the effects of temperature (305−333 K). The effects of temperature on the partition (P) and dimerization (D) coefficients were evaluated, and it was found that P decreases with increasing temperature, whereas the effects of temperature on D vary. Chemical extractions using Aliquat 336 in oleyl alcohol at temperatures ranging from 305 to 333 K show an increase in KE(1:1) values with temperature up to 313 K for acrylic and propionic acids but a decrease with increasing temperature for butyric acid over the range studied. Differences in the hydrophobicity and octanol−water partition coefficient are suggested as the reasons for the differences in extraction by the respective acids using Aliquat 336 in oleyl alcohol. The enthalpy (ΔH) and entropy (ΔS) of reaction were evaluated at different temperatures, and their difference was assessed in terms of different parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010337 [article] Extraction of acrylic, propionic, and butyric Acid using aliquat 336 in oleyl alcohol : equilibria and effect of temperature [texte imprimé] / Amit Keshav, Auteur ; Kailas L. Wasewar, Auteur ; Shri Chand, Auteur . - 2009 . - p.888–893. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.888–893 Mots-clés : Acrylic--Propionic--Butyric Acid Résumé : Reactive extractions of acrylic, propionic, and butyric acids using Aliquat 336 in oleyl alcohol were carried out to study the effects of temperature (305−333 K). The effects of temperature on the partition (P) and dimerization (D) coefficients were evaluated, and it was found that P decreases with increasing temperature, whereas the effects of temperature on D vary. Chemical extractions using Aliquat 336 in oleyl alcohol at temperatures ranging from 305 to 333 K show an increase in KE(1:1) values with temperature up to 313 K for acrylic and propionic acids but a decrease with increasing temperature for butyric acid over the range studied. Differences in the hydrophobicity and octanol−water partition coefficient are suggested as the reasons for the differences in extraction by the respective acids using Aliquat 336 in oleyl alcohol. The enthalpy (ΔH) and entropy (ΔS) of reaction were evaluated at different temperatures, and their difference was assessed in terms of different parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010337

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Parametric study of CO2 fixed carrier facilitated transport through swollen chitosan membranes / Louei A. El-Azzami in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 894–902 Titre : Parametric study of CO2 fixed carrier facilitated transport through swollen chitosan membranes Type de document : texte imprimé Auteurs : Louei A. El-Azzami, Auteur ; Eric A. Grulke, Auteur Année de publication : 2009 Article en page(s) : p. 894–902 Langues : Anglais (eng) Mots-clés : physical chemistry -- polymer. Résumé : Swollen and dry chitosan membranes were used to separate carbon dioxide from a feed gas composed of 10% CO2, 10% H2, and 80% N2 in a temperature range of 20−150 °C for a feed pressure of 1.5 atm. Swelling increased CO2 permeabilities (barrers) of chitosan membranes from 0.381 to 213 at 20 °C, 9.50 to 482 at 110 °C, and 26.1 to 399 at 150 °C, accompanied with similar trends for the separation factors: CO2/H2 and CO2/N2. The total water levels of the membranes were controlled to be the same at all temperature conditions by manipulating the relative humidities of the feed and sweep gases. This permitted direct comparison of the levels of bound and free water to carbon dioxide permeability and selectivity factors. CO2 transport in swollen chitosan membranes is mainly dominated by water-facilitated reactions of CO2 with primary amine groups of chitosan. Cussler’s model was modified to incorporate facilitated reactions caused by both free and bound water. The values of the model’s kinetic and transport parameters were consistent with the reaction chemistry of the facilitated process and the physical chemistry of the polymer. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7016916 [article] Parametric study of CO2 fixed carrier facilitated transport through swollen chitosan membranes [texte imprimé] / Louei A. El-Azzami, Auteur ; Eric A. Grulke, Auteur . - 2009 . - p. 894–902. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 894–902 Mots-clés : physical chemistry -- polymer. Résumé : Swollen and dry chitosan membranes were used to separate carbon dioxide from a feed gas composed of 10% CO2, 10% H2, and 80% N2 in a temperature range of 20−150 °C for a feed pressure of 1.5 atm. Swelling increased CO2 permeabilities (barrers) of chitosan membranes from 0.381 to 213 at 20 °C, 9.50 to 482 at 110 °C, and 26.1 to 399 at 150 °C, accompanied with similar trends for the separation factors: CO2/H2 and CO2/N2. The total water levels of the membranes were controlled to be the same at all temperature conditions by manipulating the relative humidities of the feed and sweep gases. This permitted direct comparison of the levels of bound and free water to carbon dioxide permeability and selectivity factors. CO2 transport in swollen chitosan membranes is mainly dominated by water-facilitated reactions of CO2 with primary amine groups of chitosan. Cussler’s model was modified to incorporate facilitated reactions caused by both free and bound water. The values of the model’s kinetic and transport parameters were consistent with the reaction chemistry of the facilitated process and the physical chemistry of the polymer. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7016916

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Nickel removal from waters using a surfactant-enhanced hybrid powdered activated carbon/microfiltration process. II. the influence of process variables / Coskun Aydiner in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 903–913 Titre : Nickel removal from waters using a surfactant-enhanced hybrid powdered activated carbon/microfiltration process. II. the influence of process variables Type de document : texte imprimé Auteurs : Coskun Aydiner, Auteur ; Mahmut Bayramoglu, Auteur ; Bulent Keskinler, Auteur ; Orhan Ince, Auteur Année de publication : 2009 Article en page(s) : p. 903–913 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Carbon/Microfiltration -- ProcessProcess Variables Influence Résumé : This study focused on the removal of nickel ions from aqueous solution using a surfactant-enhanced (SE) powdered activated carbon (PAC)/microfiltration (MF) hybrid membrane process. The main objective of the research is to investigate the technical performance of the process under the influences of all relevant process variables namely process time, recycling time, pH, temperature, PAC concentration, surfactant concentration, nickel concentration, cross-flow velocity, and transmembrane pressure, thus to reveal its applicability to water problems involved in heavy metal pollution. The concentrations of PAC, surfactant, metal, and H+ ion were determined as significant process stream variables, while transmembrane pressure and temperature came into prominence as significant operating variables. ANOVA calculations indicated that the total influences of these six variables on process performance realized in a range of about 93−98%. Nickel concentration and PAC amount in the feed were established as the most influential variables for nickel rejection, and surfactant rejection and permeate flux, respectively. The increase of PAC from 0.1 to 4 g/L led to a flux decline of about 60%. The most critical parameter for process performance was the mass ratio of PAC to surfactant (PAC/surfactant) per unit mass of metal removed. The process which may be effectively operated in continuous cross-flow filtration mode within a short filtration time of 30 min has crucial advantages compared to high pressure driven membrane processes and offers a promising alternative to remove heavy metal pollutants from drinking waters and metal bearing wastewaters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8004308 [article] Nickel removal from waters using a surfactant-enhanced hybrid powdered activated carbon/microfiltration process. II. the influence of process variables [texte imprimé] / Coskun Aydiner, Auteur ; Mahmut Bayramoglu, Auteur ; Bulent Keskinler, Auteur ; Orhan Ince, Auteur . - 2009 . - p. 903–913. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 903–913 Mots-clés : Carbon/Microfiltration -- ProcessProcess Variables Influence Résumé : This study focused on the removal of nickel ions from aqueous solution using a surfactant-enhanced (SE) powdered activated carbon (PAC)/microfiltration (MF) hybrid membrane process. The main objective of the research is to investigate the technical performance of the process under the influences of all relevant process variables namely process time, recycling time, pH, temperature, PAC concentration, surfactant concentration, nickel concentration, cross-flow velocity, and transmembrane pressure, thus to reveal its applicability to water problems involved in heavy metal pollution. The concentrations of PAC, surfactant, metal, and H+ ion were determined as significant process stream variables, while transmembrane pressure and temperature came into prominence as significant operating variables. ANOVA calculations indicated that the total influences of these six variables on process performance realized in a range of about 93−98%. Nickel concentration and PAC amount in the feed were established as the most influential variables for nickel rejection, and surfactant rejection and permeate flux, respectively. The increase of PAC from 0.1 to 4 g/L led to a flux decline of about 60%. The most critical parameter for process performance was the mass ratio of PAC to surfactant (PAC/surfactant) per unit mass of metal removed. The process which may be effectively operated in continuous cross-flow filtration mode within a short filtration time of 30 min has crucial advantages compared to high pressure driven membrane processes and offers a promising alternative to remove heavy metal pollutants from drinking waters and metal bearing wastewaters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8004308

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Assessment of a metal−organic framework membrane for gas separations using atomically detailed calculations: CO2, CH4, N2, H2 mixtures in MOF-5 / Seda Keskin in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 914–922 Titre : Assessment of a metal−organic framework membrane for gas separations using atomically detailed calculations: CO2, CH4, N2, H2 mixtures in MOF-5 Type de document : texte imprimé Auteurs : Seda Keskin, Auteur ; David S. Sholl, Auteur Année de publication : 2009 Article en page(s) : p. 914–922 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Metal−  Organic Framework Résumé : Metal−organic frameworks (MOFs) have emerged as a fascinating alternative to more traditional nanoporous materials. Although hundreds of different MOF structures have been synthesized in powder form, little is currently known about the potential performance of MOFs for membrane-based separations. We have used atomistic calculations to predict the performance of a MOF membrane for separation of various gas mixtures in order to provide information for material selection in membrane design. Specifically, we investigated the performance of MOF-5 as a membrane for separation of CO2/CH4, CO2/H2, CO2/N2, CH4/H2, N2/H2, and N2/CH4 mixtures at room temperature. In every case, mixture effects play a crucial role in determining the membrane performance. Although the membrane selectivities predicted for MOF-5 are not large for the mixtures we studied, our result suggest that atomistic simulations will be a useful tool for considering the large number of MOF crystal structures that are known in order to seek membrane materials with more desirable characteristics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010885 [article] Assessment of a metal−organic framework membrane for gas separations using atomically detailed calculations: CO2, CH4, N2, H2 mixtures in MOF-5 [texte imprimé] / Seda Keskin, Auteur ; David S. Sholl, Auteur . - 2009 . - p. 914–922. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 914–922 Mots-clés : Metal−  Organic Framework Résumé : Metal−organic frameworks (MOFs) have emerged as a fascinating alternative to more traditional nanoporous materials. Although hundreds of different MOF structures have been synthesized in powder form, little is currently known about the potential performance of MOFs for membrane-based separations. We have used atomistic calculations to predict the performance of a MOF membrane for separation of various gas mixtures in order to provide information for material selection in membrane design. Specifically, we investigated the performance of MOF-5 as a membrane for separation of CO2/CH4, CO2/H2, CO2/N2, CH4/H2, N2/H2, and N2/CH4 mixtures at room temperature. In every case, mixture effects play a crucial role in determining the membrane performance. Although the membrane selectivities predicted for MOF-5 are not large for the mixtures we studied, our result suggest that atomistic simulations will be a useful tool for considering the large number of MOF crystal structures that are known in order to seek membrane materials with more desirable characteristics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010885

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Electro-membrane process for In situ Ion substitution and separation of salicylic acid from its sodium salt / Mahendra Kumar in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 923–930 Titre : Electro-membrane process for In situ Ion substitution and separation of salicylic acid from its sodium salt Type de document : texte imprimé Auteurs : Mahendra Kumar, Auteur ; Bijay P. Tripathi, Auteur ; Shahi, Vinod K., Auteur Année de publication : 2009 Article en page(s) : p 923–930 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Electro-Membrane Process Résumé : An electrochemical membrane process (EMP) with three compartments (anolyte, catholyte, and central compartment) based on in-house-prepared cation-exchange membrane (CEM) was developed to achieve in situ ion substitution and recovery of salicylic acid (SAH) from its sodium salt. The physicochemical and electrochemical properties of the ion-exchange membrane (cation- and anion-exchange membrane) under standard operating conditions reveal its suitability for the proposed reactor. Experiments using sodium salicylate (SANa) solutions of different concentrations were carried out under varied applied current density to study the feasibility of the process. Overall electrochemical reaction for the in situ ion substitution and separation of SAH from SANa under operating conditions is also proposed. Results showed that developed EMP with CEMs proved promising for the in situ ion substitution and separation of SAH with recovery of SAH with current efficiency close to 90% and energy consumption around 10 kW h/kg of the SAH produced. This process was completely optimized in terms of operating conditions such as initial concentration of SANa in the central compartment, the applied current density, Na+ flux, recovery percentage, energy consumption, and current efficiency. Furthermore, the process efficiency and energy consumption of EMP for the production of SAH were compared with electrodialysis (ED) used for the separation of Na2SO4 and SAH, formed due to acidification of SANa by H2SO4. It was observed that EMP showed high current efficiency, recovery, and low energy consumption, in comparison with ED under similar experimental concentrations. It was concluded that the proposed EMP is an efficient alternate for producing SAH from SANa by economical and environmental friendly manner. Also the production of NaOH in the cathode stream is a spin off of the EMP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801317n [article] Electro-membrane process for In situ Ion substitution and separation of salicylic acid from its sodium salt [texte imprimé] / Mahendra Kumar, Auteur ; Bijay P. Tripathi, Auteur ; Shahi, Vinod K., Auteur . - 2009 . - p 923–930. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 923–930 Mots-clés : Electro-Membrane Process Résumé : An electrochemical membrane process (EMP) with three compartments (anolyte, catholyte, and central compartment) based on in-house-prepared cation-exchange membrane (CEM) was developed to achieve in situ ion substitution and recovery of salicylic acid (SAH) from its sodium salt. The physicochemical and electrochemical properties of the ion-exchange membrane (cation- and anion-exchange membrane) under standard operating conditions reveal its suitability for the proposed reactor. Experiments using sodium salicylate (SANa) solutions of different concentrations were carried out under varied applied current density to study the feasibility of the process. Overall electrochemical reaction for the in situ ion substitution and separation of SAH from SANa under operating conditions is also proposed. Results showed that developed EMP with CEMs proved promising for the in situ ion substitution and separation of SAH with recovery of SAH with current efficiency close to 90% and energy consumption around 10 kW h/kg of the SAH produced. This process was completely optimized in terms of operating conditions such as initial concentration of SANa in the central compartment, the applied current density, Na+ flux, recovery percentage, energy consumption, and current efficiency. Furthermore, the process efficiency and energy consumption of EMP for the production of SAH were compared with electrodialysis (ED) used for the separation of Na2SO4 and SAH, formed due to acidification of SANa by H2SO4. It was observed that EMP showed high current efficiency, recovery, and low energy consumption, in comparison with ED under similar experimental concentrations. It was concluded that the proposed EMP is an efficient alternate for producing SAH from SANa by economical and environmental friendly manner. Also the production of NaOH in the cathode stream is a spin off of the EMP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801317n

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Breakthrough analysis for water defluoridation using surface-tailored zeolite in a fixed bed column / Maurice S. Onyango in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 931–937 Titre : Breakthrough analysis for water defluoridation using surface-tailored zeolite in a fixed bed column Type de document : texte imprimé Auteurs : Maurice S. Onyango, Auteur ; Taile Yvonne Leswifi, Auteur ; Aoyi Ochieng, Auteur ; Dalibor Kuchar, Auteur ; Fred O Otieno, Auteur ; Hitoki Matsuda, Auteur Année de publication : 2009 Article en page(s) : p. 931–937 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Breakthrough Analysis -- Water Defluoridation Résumé : Treatment of drinking water containing fluoride ion requires a robust and an effective technique. This can be achieved by the use of an appropriate sorption material in a fixed-bed filter. Consequently, fluoride adsorption behavior, expressed as breakthrough curve (BTC), has been investigated both in a continuous and intermittent mode of operation, using charged-reversed zeolite particles in a fixed bed filter. The fluoride concentration ranged from 5 to 20 mg/L, typical of what is found in natural systems such as groundwater. In all the fluoride removal experiments, the BTC curves were consistent with the ideal s-shape. A large volume of water was processed for low initial concentration of fluoride, for slow flow velocity, and for bed containing large amount of the sorption media. Equally important, no aluminum was eluted from the zeolite structure, making the sorption media safe for water treatment. A two-parameter logistic model was used to simulate the BTCs. Separately, the fingerprint of intraparticle diffusion was confirmed through operation of the fixed-bed in an intermittent mode. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715963 [article] Breakthrough analysis for water defluoridation using surface-tailored zeolite in a fixed bed column [texte imprimé] / Maurice S. Onyango, Auteur ; Taile Yvonne Leswifi, Auteur ; Aoyi Ochieng, Auteur ; Dalibor Kuchar, Auteur ; Fred O Otieno, Auteur ; Hitoki Matsuda, Auteur . - 2009 . - p. 931–937. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 931–937 Mots-clés : Breakthrough Analysis -- Water Defluoridation Résumé : Treatment of drinking water containing fluoride ion requires a robust and an effective technique. This can be achieved by the use of an appropriate sorption material in a fixed-bed filter. Consequently, fluoride adsorption behavior, expressed as breakthrough curve (BTC), has been investigated both in a continuous and intermittent mode of operation, using charged-reversed zeolite particles in a fixed bed filter. The fluoride concentration ranged from 5 to 20 mg/L, typical of what is found in natural systems such as groundwater. In all the fluoride removal experiments, the BTC curves were consistent with the ideal s-shape. A large volume of water was processed for low initial concentration of fluoride, for slow flow velocity, and for bed containing large amount of the sorption media. Equally important, no aluminum was eluted from the zeolite structure, making the sorption media safe for water treatment. A two-parameter logistic model was used to simulate the BTCs. Separately, the fingerprint of intraparticle diffusion was confirmed through operation of the fixed-bed in an intermittent mode. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715963

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preparation and Adsorption properties of thiol-functionalized mesoporous silica microspheres / Yoshikazu Miyake in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.0 938–943 Titre : preparation and Adsorption properties of thiol-functionalized mesoporous silica microspheres Type de document : texte imprimé Auteurs : Yoshikazu Miyake, Auteur ; Masanori Yosuke, Auteur ; Eiichi Azechi, Auteur ; Sadao Araki, Auteur ; Shunsuke Tanaka, Auteur Année de publication : 2009 Article en page(s) : p.0 938–943 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : silica microspheres Résumé : Mesoporous silica microspheres (MSM) approximately 1.0 μm in diameter were prepared by the hydrolysis and condensation of tetraethoxysilane (TEOS) under the presence of dodecylamine (DDA) as a molecular template and catalyst in ethanol−water solution. Isolated MSM were obtained in a narrow range of experimental conditions, which were experimentally correlated by the linear relationship between the molar ratio of ethanol and TEOS and that of DDA and TEOS. Isolated MSM modified with thiol groups were also prepared under similar experimental conditions, by co-condensation of TEOS and 3-mercaptopropyltrimethoxysilane (MPTMS). The thiol-functionalized MSM (SH-MSM) adsorbed silver ions from an aqueous solution. Asymmetrical polystyrene film, in which the SH-MSM were self-assembled on the surface of the water phase side of the film, was obtained by spreading and polymerizing of styrene monomer with dispersed SH-MSM on the water surface. The polymer film containing SH-MSM also effectively adsorbed silver ions. [article] preparation and Adsorption properties of thiol-functionalized mesoporous silica microspheres [texte imprimé] / Yoshikazu Miyake, Auteur ; Masanori Yosuke, Auteur ; Eiichi Azechi, Auteur ; Sadao Araki, Auteur ; Shunsuke Tanaka, Auteur . - 2009 . - p.0 938–943. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p.0 938–943 Mots-clés : silica microspheres Résumé : Mesoporous silica microspheres (MSM) approximately 1.0 μm in diameter were prepared by the hydrolysis and condensation of tetraethoxysilane (TEOS) under the presence of dodecylamine (DDA) as a molecular template and catalyst in ethanol−water solution. Isolated MSM were obtained in a narrow range of experimental conditions, which were experimentally correlated by the linear relationship between the molar ratio of ethanol and TEOS and that of DDA and TEOS. Isolated MSM modified with thiol groups were also prepared under similar experimental conditions, by co-condensation of TEOS and 3-mercaptopropyltrimethoxysilane (MPTMS). The thiol-functionalized MSM (SH-MSM) adsorbed silver ions from an aqueous solution. Asymmetrical polystyrene film, in which the SH-MSM were self-assembled on the surface of the water phase side of the film, was obtained by spreading and polymerizing of styrene monomer with dispersed SH-MSM on the water surface. The polymer film containing SH-MSM also effectively adsorbed silver ions.

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PH-sensitive magnetic ion exchanger for protein separation / Liangrong Yang in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 944–950 Titre : PH-sensitive magnetic ion exchanger for protein separation Type de document : texte imprimé Auteurs : Liangrong Yang, Auteur ; Chen, Guo, Auteur ; Shu Chen, Auteur ; Feng Wang, Auteur ; Jing Wang, Auteur ; Zhentao An, Auteur Année de publication : 2009 Article en page(s) : p. 944–950 Note générale : chimical engineering Langues : Anglais (eng) Mots-clés : pH-sensitive Résumé : A pH-sensitive magnetic ion exchanger was synthesized by binding carboxymethylated chitosan (CMCH) covalently on the surface of Fe3O4 nanoparticles. The diameter for magnetic particles observed at 25 °C was 15 nm. The ion exchanger was superparamagnetic with a saturation magnetization of 64.21 emu/g and an isoelectric point (pI) of 5.75. In a model system, the laccase adsorption capacity reached equilibrium within 15 min (pH 5). The adsorption process followed the Langmuir adsorption isotherm, and the maximum equilibrium adsorption capacity was calculated to be 198.81 mg/g. The laccase can be completely desorbed at pH 8. About 97% laccase can be effectively desorbed from the surface of particles within 15 min. Moreover, the specific activity of the laccase remained constant during the adsorption and desorption process. Finally, the pH-sensitive magnetic ion exchanger was used for separation of laccase directly from culture supernatant, and nearly pure laccase was isolated by a single step with an activity recovery rate of 63%. [article] PH-sensitive magnetic ion exchanger for protein separation [texte imprimé] / Liangrong Yang, Auteur ; Chen, Guo, Auteur ; Shu Chen, Auteur ; Feng Wang, Auteur ; Jing Wang, Auteur ; Zhentao An, Auteur . - 2009 . - p. 944–950. chimical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 944–950 Mots-clés : pH-sensitive Résumé : A pH-sensitive magnetic ion exchanger was synthesized by binding carboxymethylated chitosan (CMCH) covalently on the surface of Fe3O4 nanoparticles. The diameter for magnetic particles observed at 25 °C was 15 nm. The ion exchanger was superparamagnetic with a saturation magnetization of 64.21 emu/g and an isoelectric point (pI) of 5.75. In a model system, the laccase adsorption capacity reached equilibrium within 15 min (pH 5). The adsorption process followed the Langmuir adsorption isotherm, and the maximum equilibrium adsorption capacity was calculated to be 198.81 mg/g. The laccase can be completely desorbed at pH 8. About 97% laccase can be effectively desorbed from the surface of particles within 15 min. Moreover, the specific activity of the laccase remained constant during the adsorption and desorption process. Finally, the pH-sensitive magnetic ion exchanger was used for separation of laccase directly from culture supernatant, and nearly pure laccase was isolated by a single step with an activity recovery rate of 63%.

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Selective adsorption for removal of nitrogen compounds from liquid hydrocarbon streams over carbon- and alumina-based adsorbents / Masoud Almarri in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 951–960 Titre : Selective adsorption for removal of nitrogen compounds from liquid hydrocarbon streams over carbon- and alumina-based adsorbents Type de document : texte imprimé Auteurs : Masoud Almarri, Auteur ; Xiaoliang Ma, Auteur ; Chunshan Song, Auteur Année de publication : 2009 Article en page(s) : p 951–960 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Hydrocarbon--Liquid Résumé : In order to explore the adsorptive denitrogenation of liquid hydrocarbon streams for producing ultraclean fuels, the adsorption performance of seven representative activated carbon samples and three activated alumina samples was evaluated in a batch adsorption system and a fixed-bed flow adsorption system for removing quinoline and indole from a model diesel fuel in the coexistence of sulfur compounds and aromatics. Different adsorbents show quite different selectivity toward basic and nonbasic nitrogen compounds (quinoline and indole) and sulfur compounds (dibenzothiophene and 4,6-dimethyldibenzothiophene). The activated carbons generally show higher capacity than activated alumina samples for removing the nitrogen compounds. The adsorption capacity and selectivity of the activated carbons for nitrogen compounds were further correlated with their textural properties and oxygen content. It was found that (1) the microporous surface area and micropore volume are not a key factor for removal of the nitrogen compounds in the tested activated carbons; (2) the oxygen functionality of the activated carbons may play a more important role in determining the adsorption capacity for the nitrogen compounds since the adsorption capacity for nitrogen compounds increases with increase in the oxygen concentration of the activated carbons; and (3) the type of the oxygen-functional groups may be crucial in determining their selectivity for various nitrogen or sulfur compounds. In addition, regeneration of the saturated adsorbents was conducted by the toluene washing followed by the heating to remove the remained toluene. The results show that the spent activated carbons can be regenerated to completely recover the adsorption capacity. The high capacity and selectivity of carbon-based adsorbents for the nitrogen compounds, along with their good regenerability, indicate that the activated carbons may be promising adsorbents for deep denitrogenation of liquid hydrocarbon streams. [article] Selective adsorption for removal of nitrogen compounds from liquid hydrocarbon streams over carbon- and alumina-based adsorbents [texte imprimé] / Masoud Almarri, Auteur ; Xiaoliang Ma, Auteur ; Chunshan Song, Auteur . - 2009 . - p 951–960. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 951–960 Mots-clés : Hydrocarbon--Liquid Résumé : In order to explore the adsorptive denitrogenation of liquid hydrocarbon streams for producing ultraclean fuels, the adsorption performance of seven representative activated carbon samples and three activated alumina samples was evaluated in a batch adsorption system and a fixed-bed flow adsorption system for removing quinoline and indole from a model diesel fuel in the coexistence of sulfur compounds and aromatics. Different adsorbents show quite different selectivity toward basic and nonbasic nitrogen compounds (quinoline and indole) and sulfur compounds (dibenzothiophene and 4,6-dimethyldibenzothiophene). The activated carbons generally show higher capacity than activated alumina samples for removing the nitrogen compounds. The adsorption capacity and selectivity of the activated carbons for nitrogen compounds were further correlated with their textural properties and oxygen content. It was found that (1) the microporous surface area and micropore volume are not a key factor for removal of the nitrogen compounds in the tested activated carbons; (2) the oxygen functionality of the activated carbons may play a more important role in determining the adsorption capacity for the nitrogen compounds since the adsorption capacity for nitrogen compounds increases with increase in the oxygen concentration of the activated carbons; and (3) the type of the oxygen-functional groups may be crucial in determining their selectivity for various nitrogen or sulfur compounds. In addition, regeneration of the saturated adsorbents was conducted by the toluene washing followed by the heating to remove the remained toluene. The results show that the spent activated carbons can be regenerated to completely recover the adsorption capacity. The high capacity and selectivity of carbon-based adsorbents for the nitrogen compounds, along with their good regenerability, indicate that the activated carbons may be promising adsorbents for deep denitrogenation of liquid hydrocarbon streams.

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Removal of cu(II) and ni(II) from industrial effluents by brown seaweed, cystoseira indica / Shaik Basha in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 961–975 Titre : Removal of cu(II) and ni(II) from industrial effluents by brown seaweed, cystoseira indica Type de document : texte imprimé Auteurs : Shaik Basha, Auteur ; Z. V. P. Murthy, Auteur ; B. Jha, Auteur Année de publication : 2009 Article en page(s) : p. 961–975 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Cystoseira -- biomass Résumé : The biomass of Cystoseira indica (RB) was chemically modified by cross-linking it with epichlorohydrin (CB1, CB2), and the same was oxidized by potassium permanganate (CB3) which was later employed for the treatment of Cu(II) and Ni(II) from effluents. The results indicated that biosorption equilibriums were rapidly established in about 30 and 75 min for Cu(II) and Ni(II), respectively. The metal biosorption was strictly pH dependent, and maximum removal of metals was observed at pH 6.0. The biosorption data dovetail the Langmuir isotherm, and the process obeyed pseudo-second-order kinetics. An intraparticle diffusion based Weber−Morris model was applied to evaluate rate-limiting steps, and the results suggested that film diffusion controlled the overall biosorption process. Fourier transform infrared analysis revealed that amino, hydroxyl, carboxyl, ether, and hydroxyl functional groups were involved in the metal binding and the sorption process was dominated by complexation as well as ion exchange. The loaded biosorbent was regenerated using HCl and used repeatedly over five cycles with little loss of uptake capacity beyond the second cycle. [article] Removal of cu(II) and ni(II) from industrial effluents by brown seaweed, cystoseira indica [texte imprimé] / Shaik Basha, Auteur ; Z. V. P. Murthy, Auteur ; B. Jha, Auteur . - 2009 . - p. 961–975. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 961–975 Mots-clés : Cystoseira -- biomass Résumé : The biomass of Cystoseira indica (RB) was chemically modified by cross-linking it with epichlorohydrin (CB1, CB2), and the same was oxidized by potassium permanganate (CB3) which was later employed for the treatment of Cu(II) and Ni(II) from effluents. The results indicated that biosorption equilibriums were rapidly established in about 30 and 75 min for Cu(II) and Ni(II), respectively. The metal biosorption was strictly pH dependent, and maximum removal of metals was observed at pH 6.0. The biosorption data dovetail the Langmuir isotherm, and the process obeyed pseudo-second-order kinetics. An intraparticle diffusion based Weber−Morris model was applied to evaluate rate-limiting steps, and the results suggested that film diffusion controlled the overall biosorption process. Fourier transform infrared analysis revealed that amino, hydroxyl, carboxyl, ether, and hydroxyl functional groups were involved in the metal binding and the sorption process was dominated by complexation as well as ion exchange. The loaded biosorbent was regenerated using HCl and used repeatedly over five cycles with little loss of uptake capacity beyond the second cycle.

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Annatto powder production in a spouted bed: an experimental and CFD study / Fabiano G. Cunha in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 976–982 Titre : Annatto powder production in a spouted bed: an experimental and CFD study Type de document : texte imprimé Auteurs : Fabiano G. Cunha, Auteur ; Kassia G. Santos, Auteur ; Carlos H. Ataíde, Auteur ; Norman Epstein, Auteur Année de publication : 2009 Article en page(s) : p 976–982 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : fluid dynamic Résumé : The mechanical extraction of the bixin from Bixa orellana seeds using a spouted bed was investigated in this work. The experimental program was divided into two main steps. In the first step, a two-level factorial experimental design was used to analyze the influence of the main process variables on the mechanical extraction responses. The second step of the experiment was carried out to evaluate the effect of the distance between the draft tube and the conical base (ht). Computational fluid dynamic technique was used to understand seed flow and the effect of ht on the mechanical extraction process. The results obtained showed that the presence of the draft tube was the variable that most strongly affected the powder extraction. The best condition for the bixin extraction from B. orellana seeds was the one when the draft tube was positioned at 4 cm from the air inlet. [article] Annatto powder production in a spouted bed: an experimental and CFD study [texte imprimé] / Fabiano G. Cunha, Auteur ; Kassia G. Santos, Auteur ; Carlos H. Ataíde, Auteur ; Norman Epstein, Auteur . - 2009 . - p 976–982. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 976–982 Mots-clés : fluid dynamic Résumé : The mechanical extraction of the bixin from Bixa orellana seeds using a spouted bed was investigated in this work. The experimental program was divided into two main steps. In the first step, a two-level factorial experimental design was used to analyze the influence of the main process variables on the mechanical extraction responses. The second step of the experiment was carried out to evaluate the effect of the distance between the draft tube and the conical base (ht). Computational fluid dynamic technique was used to understand seed flow and the effect of ht on the mechanical extraction process. The results obtained showed that the presence of the draft tube was the variable that most strongly affected the powder extraction. The best condition for the bixin extraction from B. orellana seeds was the one when the draft tube was positioned at 4 cm from the air inlet.

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Effects of organic impurities on chloralkali membrane electrolyzer performance / James M. Silva in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 983–987 Titre : Effects of organic impurities on chloralkali membrane electrolyzer performance Type de document : texte imprimé Auteurs : James M. Silva, Auteur ; Grigorii L. Soloveichik, Auteur ; Donald Novak, Auteur Année de publication : 2009 Article en page(s) : p 983–987 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : chloralkali membrane electrolyze -- Effects Résumé : Laboratory chloralkali membrane electrolyzer tests showed a dramatic voltage increase and mild catholyte foaming when low levels of chloromethyl triethylammonium chloride (CTACl), a quaternary ammonium salt, were present in the feed brine. Current efficiency was not measurably affected by CTACl. In contrast, laboratory membrane electrolyzers showed no voltage sensitivity to sodium gluconate, bisphenol A, or triethylamine, contaminants that are often present in interfacial polycarbonate plant byproduct brine. The voltage increase and onset of catholyte foaming were rapid when the feed was switched from ultrapure brine to CTACl-containing brine, requiring about 3 h to achieve a steady state. Both effects were completely reversible, but the system required about 20 h to return to baseline voltage after the feed was switched back to ultrapure brine. The cell voltage was remarkably sensitive to CTACl: 8 ppm CTACl yielded a 200 mV voltage increase vs ultrapure brine. Cyclic voltammetric measurements with CTACl-spiked brine showed no effect of CTACl on anode or cathode overpotentials. At steady state, 87% of the feed chloromethyl triethylammonium ion (CTA+) is recovered either in the electrolyzer catholyte as the hydroxide, CTAOH (56%), or in the depleted brine as CTACl (31%), which demonstrates that CTA+ is rather stable toward chloralkali conditions. It is concluded that the increased cell voltage is caused by chloromethyl triethylammonium ions adsorbing onto membrane ion exchange sites, which reduces the population of sites for sodium ion transport, and that catholyte foaming is caused by the presence of CTAOH in the catholyte. An adsorbent screening study showed that various carbons, including Ambersorb 572, are effective for CTACl removal from brine. A laboratory electrolyzer fed with Ambersorb 572 treated plant brine showed normal voltage and no catholyte foaming. [article] Effects of organic impurities on chloralkali membrane electrolyzer performance [texte imprimé] / James M. Silva, Auteur ; Grigorii L. Soloveichik, Auteur ; Donald Novak, Auteur . - 2009 . - p 983–987. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 983–987 Mots-clés : chloralkali membrane electrolyze -- Effects Résumé : Laboratory chloralkali membrane electrolyzer tests showed a dramatic voltage increase and mild catholyte foaming when low levels of chloromethyl triethylammonium chloride (CTACl), a quaternary ammonium salt, were present in the feed brine. Current efficiency was not measurably affected by CTACl. In contrast, laboratory membrane electrolyzers showed no voltage sensitivity to sodium gluconate, bisphenol A, or triethylamine, contaminants that are often present in interfacial polycarbonate plant byproduct brine. The voltage increase and onset of catholyte foaming were rapid when the feed was switched from ultrapure brine to CTACl-containing brine, requiring about 3 h to achieve a steady state. Both effects were completely reversible, but the system required about 20 h to return to baseline voltage after the feed was switched back to ultrapure brine. The cell voltage was remarkably sensitive to CTACl: 8 ppm CTACl yielded a 200 mV voltage increase vs ultrapure brine. Cyclic voltammetric measurements with CTACl-spiked brine showed no effect of CTACl on anode or cathode overpotentials. At steady state, 87% of the feed chloromethyl triethylammonium ion (CTA+) is recovered either in the electrolyzer catholyte as the hydroxide, CTAOH (56%), or in the depleted brine as CTACl (31%), which demonstrates that CTA+ is rather stable toward chloralkali conditions. It is concluded that the increased cell voltage is caused by chloromethyl triethylammonium ions adsorbing onto membrane ion exchange sites, which reduces the population of sites for sodium ion transport, and that catholyte foaming is caused by the presence of CTAOH in the catholyte. An adsorbent screening study showed that various carbons, including Ambersorb 572, are effective for CTACl removal from brine. A laboratory electrolyzer fed with Ambersorb 572 treated plant brine showed normal voltage and no catholyte foaming.

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Quality control of food products using image analysis and multivariate statistical tools / Ana C Pereira in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 988–998 Titre : Quality control of food products using image analysis and multivariate statistical tools Type de document : texte imprimé Auteurs : Ana C Pereira, Auteur ; Marco S. Reis, Auteur ; Pedro M. Saraiva, Auteur Année de publication : 2009 Article en page(s) : p 988–998 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : food products--Quality Control Résumé : Visual appearance is an important feature in the quality assessment of food products, since it plays a key role in the decisions made by consumers. Frequently, its evaluation is carried out by a panel of experts from the quality department who analyze, by visual inspection, samples of product taken from the process. It is well-known that such methodologies of assessment suffer from several drawbacks, such as subjectivity, limited precision, and lack of stability over time, even for well-trained personnel, although extensive training programs can improve assessment performance. In this context, we present in this paper results regarding the development of an automated methodology for assessing the visual appearance of cereal flakes, in what concerns a particular quality feature, relative to the existence of regions where cereal coating is inadequate. The proposed procedure is able to extract the necessary information from images taken from product samples, leading to an objective, stable, and quantitative quality control measurement system for this property. The developed algorithm essentially consists of implementing a supervised classification methodology, based on the estimated Mahalanobis distance for assessing proximity in the color space, while incorporating the natural variability and color correlations found in cereal flakes. This procedure also integrates fuzzy logic reasoning for samples falling under regions closer to the classes’ boundaries. Results obtained from a real industrial plant indicate that it is indeed possible to classify different samples of flakes according to classes previously defined. They also provide a sound basis for further developments, in particular regarding the generation of metrics for quality assessment and the implementation of a similar procedure online and in situ. [article] Quality control of food products using image analysis and multivariate statistical tools [texte imprimé] / Ana C Pereira, Auteur ; Marco S. Reis, Auteur ; Pedro M. Saraiva, Auteur . - 2009 . - p 988–998. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 988–998 Mots-clés : food products--Quality Control Résumé : Visual appearance is an important feature in the quality assessment of food products, since it plays a key role in the decisions made by consumers. Frequently, its evaluation is carried out by a panel of experts from the quality department who analyze, by visual inspection, samples of product taken from the process. It is well-known that such methodologies of assessment suffer from several drawbacks, such as subjectivity, limited precision, and lack of stability over time, even for well-trained personnel, although extensive training programs can improve assessment performance. In this context, we present in this paper results regarding the development of an automated methodology for assessing the visual appearance of cereal flakes, in what concerns a particular quality feature, relative to the existence of regions where cereal coating is inadequate. The proposed procedure is able to extract the necessary information from images taken from product samples, leading to an objective, stable, and quantitative quality control measurement system for this property. The developed algorithm essentially consists of implementing a supervised classification methodology, based on the estimated Mahalanobis distance for assessing proximity in the color space, while incorporating the natural variability and color correlations found in cereal flakes. This procedure also integrates fuzzy logic reasoning for samples falling under regions closer to the classes’ boundaries. Results obtained from a real industrial plant indicate that it is indeed possible to classify different samples of flakes according to classes previously defined. They also provide a sound basis for further developments, in particular regarding the generation of metrics for quality assessment and the implementation of a similar procedure online and in situ.

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Comparison of various micromixing approaches for computational fluid dynamics simulation of barium sulfate precipitation in tubular reactors / Alper A. Öncül in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 999–1007 Titre : Comparison of various micromixing approaches for computational fluid dynamics simulation of barium sulfate precipitation in tubular reactors Type de document : texte imprimé Auteurs : Alper A. Öncül, Auteur ; Gábor Janiga, Auteur ; Dominique Thévenin, Auteur Année de publication : 2009 Article en page(s) : p 999–1007 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Computational Fluid Dynamics Résumé : Precipitation (also called reactive crystallization) processes are widely employed in the chemical industry in a variety of reactors and for different purposes. The properties and quality of the resulting particulate product are highly dependent on the mixing conditions in the reactor, since precipitation reactions are mostly fast: the reaction time is usually of the order of or shorter than the mixing time. Therefore, experimental and numerical investigations of precipitation processes under different hydrodynamic conditions constitute an interesting topic. In this work, precipitation of barium sulfate (BaSO4) is numerically investigated in two different tubular reactors, taking micromixing effects into account. Different models are employed with an increasing level of complexity. These models and the reaction kinetics are first explained. RANS-based axisymmetric computations are performed using the industrial CFD code FLUENT 6.3 at steady-state. The results of the simulations are then presented and discussed in detail. Moreover, quantitative comparisons with experimental data obtained from literature are also employed for validation. Finally, concluding remarks and possible model improvements are listed. [article] Comparison of various micromixing approaches for computational fluid dynamics simulation of barium sulfate precipitation in tubular reactors [texte imprimé] / Alper A. Öncül, Auteur ; Gábor Janiga, Auteur ; Dominique Thévenin, Auteur . - 2009 . - p 999–1007. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 999–1007 Mots-clés : Computational Fluid Dynamics Résumé : Precipitation (also called reactive crystallization) processes are widely employed in the chemical industry in a variety of reactors and for different purposes. The properties and quality of the resulting particulate product are highly dependent on the mixing conditions in the reactor, since precipitation reactions are mostly fast: the reaction time is usually of the order of or shorter than the mixing time. Therefore, experimental and numerical investigations of precipitation processes under different hydrodynamic conditions constitute an interesting topic. In this work, precipitation of barium sulfate (BaSO4) is numerically investigated in two different tubular reactors, taking micromixing effects into account. Different models are employed with an increasing level of complexity. These models and the reaction kinetics are first explained. RANS-based axisymmetric computations are performed using the industrial CFD code FLUENT 6.3 at steady-state. The results of the simulations are then presented and discussed in detail. Moreover, quantitative comparisons with experimental data obtained from literature are also employed for validation. Finally, concluding remarks and possible model improvements are listed.

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Angle-resolved particle image velocimetry measurements of flow and turbulence fields in small-scale stirred vessels of different mixer configurations / Kenneth H. K. Chung in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 1008–1018 Titre : Angle-resolved particle image velocimetry measurements of flow and turbulence fields in small-scale stirred vessels of different mixer configurations Type de document : texte imprimé Auteurs : Kenneth H. K. Chung, Auteur ; Mark J. H. Simmons, Auteur ; Mostafa Barigou, Auteur Année de publication : 2009 Article en page(s) : p. 1008–1018 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Angle-Resolved Particle Image --configurations Résumé : Angle-resolved particle image velocimetry measurements were conducted at one degree intervals in miniature vessels of four different configurations used in high-throughput experimentation. The four vessels—standard fully baffled, unbaffled, off-center or eccentric impeller, and square section—were agitated by an up-pumping six-blade 45° pitched blade turbine (PBT). The effect of periodicity was revealed in all configurations but was restricted to the impeller discharge and inflow regions. The square vessel achieved the strongest axial-radial flow field among all configurations. The smallest overestimation in the computation of turbulent kinetic energy by the ensemble time average method, otherwise referred to as pseudoturbulence, was achieved in the eccentric and square configurations. The up-pumping PBT shed trailing vortices mainly in a radial direction with relatively little axial movement. The highest axial vortex position was achieved in the square vessel, which may be partly responsible for its lower mixing time compared to other configurations. The measurements obtained here in the high-transitional regime suggest that the square configuration performs better than other configurations and can be a good replacement for the fully baffled vessel in commercial high-throughput experimentation units where baffles are usually prohibited. This result was confirmed from mixing time measurements made using planar laser induced fluorescence where the superiority of the square vessel was demonstrated. [article] Angle-resolved particle image velocimetry measurements of flow and turbulence fields in small-scale stirred vessels of different mixer configurations [texte imprimé] / Kenneth H. K. Chung, Auteur ; Mark J. H. Simmons, Auteur ; Mostafa Barigou, Auteur . - 2009 . - p. 1008–1018. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 1008–1018 Mots-clés : Angle-Resolved Particle Image --configurations Résumé : Angle-resolved particle image velocimetry measurements were conducted at one degree intervals in miniature vessels of four different configurations used in high-throughput experimentation. The four vessels—standard fully baffled, unbaffled, off-center or eccentric impeller, and square section—were agitated by an up-pumping six-blade 45° pitched blade turbine (PBT). The effect of periodicity was revealed in all configurations but was restricted to the impeller discharge and inflow regions. The square vessel achieved the strongest axial-radial flow field among all configurations. The smallest overestimation in the computation of turbulent kinetic energy by the ensemble time average method, otherwise referred to as pseudoturbulence, was achieved in the eccentric and square configurations. The up-pumping PBT shed trailing vortices mainly in a radial direction with relatively little axial movement. The highest axial vortex position was achieved in the square vessel, which may be partly responsible for its lower mixing time compared to other configurations. The measurements obtained here in the high-transitional regime suggest that the square configuration performs better than other configurations and can be a good replacement for the fully baffled vessel in commercial high-throughput experimentation units where baffles are usually prohibited. This result was confirmed from mixing time measurements made using planar laser induced fluorescence where the superiority of the square vessel was demonstrated.

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Combined use of PEPT and ERT in the study of aluminum hydroxide precipitation / Iwan Edwards in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 1019–1028 Titre : Combined use of PEPT and ERT in the study of aluminum hydroxide precipitation Type de document : texte imprimé Auteurs : Iwan Edwards, Auteur ; Sean A. Axon, Auteur ; Mostafa Barigou, Auteur ; Hugh Stitt, Auteur Année de publication : 2009 Article en page(s) : p 1019–1028 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Aluminum Hydroxide--Study Résumé : The application of multimodal tomographic techniques to the in situ study of the semibatch precipitation of aluminum hydroxide, an industrially important alumina precursor, has been developed. For the first time Electrical Resistance Tomography (ERT) and Positron Emission Particle Tracking (PEPT) have been used concomitantly to study precipitation and hydrodynamics. This combination of techniques allows a step change in our ability to understand industrial precipitation processes. The semibatch precipitation of aluminum hydroxide was investigated in a stirred vessel operated with different configurations. Mixing conditions during semi batch precipitation have been shown to determine particle properties. Variables such as impeller design, power input, and feed location were used to provide different mixing conditions at the feed point where the reagents contact and precipitation takes place. The mixing performance during precipitation can be analyzed using ERT, with information of how the feed plume is dispersed under different mixing conditions. The flow conditions in the feed region can be characterized using PEPT. Together, the techniques can establish how the feed plume is dissipated into the bulk fluid. [article] Combined use of PEPT and ERT in the study of aluminum hydroxide precipitation [texte imprimé] / Iwan Edwards, Auteur ; Sean A. Axon, Auteur ; Mostafa Barigou, Auteur ; Hugh Stitt, Auteur . - 2009 . - p 1019–1028. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 1019–1028 Mots-clés : Aluminum Hydroxide--Study Résumé : The application of multimodal tomographic techniques to the in situ study of the semibatch precipitation of aluminum hydroxide, an industrially important alumina precursor, has been developed. For the first time Electrical Resistance Tomography (ERT) and Positron Emission Particle Tracking (PEPT) have been used concomitantly to study precipitation and hydrodynamics. This combination of techniques allows a step change in our ability to understand industrial precipitation processes. The semibatch precipitation of aluminum hydroxide was investigated in a stirred vessel operated with different configurations. Mixing conditions during semi batch precipitation have been shown to determine particle properties. Variables such as impeller design, power input, and feed location were used to provide different mixing conditions at the feed point where the reagents contact and precipitation takes place. The mixing performance during precipitation can be analyzed using ERT, with information of how the feed plume is dispersed under different mixing conditions. The flow conditions in the feed region can be characterized using PEPT. Together, the techniques can establish how the feed plume is dissipated into the bulk fluid.

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Comparing the performance of recirculating cyclones applied to the dry scrubbing of gaseous HCl with hydrated lime / Vania Chibante in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 1029–1035 Titre : Comparing the performance of recirculating cyclones applied to the dry scrubbing of gaseous HCl with hydrated lime Type de document : texte imprimé Auteurs : Vania Chibante, Auteur ; Ana M. Fonseca, Auteur ; Romualdo L. R. Salcedo, Auteur Année de publication : 2009 Article en page(s) : p. 1029–1035 Note générale : chimical engineering Langues : Anglais (eng) Mots-clés : Recirculating cyclone systems Résumé : Recirculating cyclone systems, combining a numerically optimized reverse flow gas cyclone (RS_VHE geometry) with a straight-through cyclone concentrator, were employed as reaction chambers for the dry scrubbing of gaseous hydrogen chloride with solid hydrated lime particles. The performance of this technology was tested at laboratory scale with two differently sized RS_VHE cyclones (0.020 and 0.026 m internal diameter) coupled to the same recirculator of 0.020 m internal diameter. The experimental conditions were the following: reaction temperature ≈ 326 K, gas flow rate ≈ 2.9 × 10−4 m3·s−1 at STP, and relative humidity of the gas ≈ 8.5%. The experimental variables were the solids feed rate [(1.0−9.2) × 10−7 kg·s−1] and HCl concentration in the inlet gas [(0.35−2.8) × 10−2 mol·m−3], giving different values for the ratio between the amount of fresh hydrated lime and HCl feed at the inlet of the recirculating cyclone systems (R) and that corresponding to the stoichiometric quantity (SR). The acid removal efficiencies ranged from 10 to 96%, and the best performances were obtained for high values of the ratio R/SR. Increasing the cyclone diameter while maintaining cyclone geometry improved the performance of the acid gas removal as well as the solid reactant conversion, but the average particle collection efficiency was lowered from (98.0 ± 0.7)% to (89.3 ± 1.7)%. [article] Comparing the performance of recirculating cyclones applied to the dry scrubbing of gaseous HCl with hydrated lime [texte imprimé] / Vania Chibante, Auteur ; Ana M. Fonseca, Auteur ; Romualdo L. R. Salcedo, Auteur . - 2009 . - p. 1029–1035. chimical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 1029–1035 Mots-clés : Recirculating cyclone systems Résumé : Recirculating cyclone systems, combining a numerically optimized reverse flow gas cyclone (RS_VHE geometry) with a straight-through cyclone concentrator, were employed as reaction chambers for the dry scrubbing of gaseous hydrogen chloride with solid hydrated lime particles. The performance of this technology was tested at laboratory scale with two differently sized RS_VHE cyclones (0.020 and 0.026 m internal diameter) coupled to the same recirculator of 0.020 m internal diameter. The experimental conditions were the following: reaction temperature ≈ 326 K, gas flow rate ≈ 2.9 × 10−4 m3·s−1 at STP, and relative humidity of the gas ≈ 8.5%. The experimental variables were the solids feed rate [(1.0−9.2) × 10−7 kg·s−1] and HCl concentration in the inlet gas [(0.35−2.8) × 10−2 mol·m−3], giving different values for the ratio between the amount of fresh hydrated lime and HCl feed at the inlet of the recirculating cyclone systems (R) and that corresponding to the stoichiometric quantity (SR). The acid removal efficiencies ranged from 10 to 96%, and the best performances were obtained for high values of the ratio R/SR. Increasing the cyclone diameter while maintaining cyclone geometry improved the performance of the acid gas removal as well as the solid reactant conversion, but the average particle collection efficiency was lowered from (98.0 ± 0.7)% to (89.3 ± 1.7)%.

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Pyrrolidone derivatives in water solution / Rafael Alcalde in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 1036–1050 Titre : Pyrrolidone derivatives in water solution : an experimental and theoretical perspective Type de document : texte imprimé Auteurs : Rafael Alcalde, Auteur ; María J. Dávila, Auteur ; Santiago Aparicio, Auteur Année de publication : 2009 Article en page(s) : p 1036–1050 Note générale : chemical enginireeing Langues : Anglais (eng) Mots-clés : Pyrrolidone derivatives --Theoretical Perspective Résumé : In this paper thermophysical properties of 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone, in binary and ternary liquid mixtures with water are reported at 298.15 K and 0.1 MPa over the whole composition range. Derived excess and mixing properties were used to analyze mixtures’ structure. To infer a detailed picture of the intermolecular interactions in the studied fluids, attenuated total reflection infrared absorption spectroscopy was used. To study fluid properties from a molecular viewpoint, density functional theory computations were carried out, leading to structural and energetic information. Formation of H-bonding and dipolar interactions between cyclic amides and with water were observed, resulting in complex fluid structures that were stronger in binary mixtures containing water than in ternary ones. Intermolecular forces are weakened upon mixing by the presence of a second cyclic amide in the mixture. [article] Pyrrolidone derivatives in water solution : an experimental and theoretical perspective [texte imprimé] / Rafael Alcalde, Auteur ; María J. Dávila, Auteur ; Santiago Aparicio, Auteur . - 2009 . - p 1036–1050. chemical enginireeing Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 1036–1050 Mots-clés : Pyrrolidone derivatives --Theoretical Perspective Résumé : In this paper thermophysical properties of 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone, in binary and ternary liquid mixtures with water are reported at 298.15 K and 0.1 MPa over the whole composition range. Derived excess and mixing properties were used to analyze mixtures’ structure. To infer a detailed picture of the intermolecular interactions in the studied fluids, attenuated total reflection infrared absorption spectroscopy was used. To study fluid properties from a molecular viewpoint, density functional theory computations were carried out, leading to structural and energetic information. Formation of H-bonding and dipolar interactions between cyclic amides and with water were observed, resulting in complex fluid structures that were stronger in binary mixtures containing water than in ternary ones. Intermolecular forces are weakened upon mixing by the presence of a second cyclic amide in the mixture.

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