Dépouillements

Coupling gliding discharge treatment and catalysis by oyster shell powder for pollution abatement of surface waters / Estella Njoyim in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9773–9780 Titre : Coupling gliding discharge treatment and catalysis by oyster shell powder for pollution abatement of surface waters Type de document : texte imprimé Auteurs : Estella Njoyim, Auteur ; Paul Ghogomu, Auteur ; Samuel Laminsi, Auteur Année de publication : 2010 Article en page(s) : pp. 9773–9780 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Oyster shell powder Gliding electric discharge Résumé : Adsorption on oyster shell powder (OS) was combined with gliding electric discharge to abate pollution of surface waters sampled in brooks passing through large Cameroonian cities and collecting industrial and domestic wastes. OS powder incorporated into the aqueous samples after exposure to the discharge improved pollutant abatement as compared to the plasma treatment alone. The process kinetics involved pseudo zero-order reactions for treatments longer than 5 min. Total organic carbon linearly decreases with increasing exposure time to the discharge (k ≈ 0.13 mgC L−1 min−1 for a 1 g L−1 standard OS charge). The rate constant linearly increases with the incorporated OS mass, which increases the sample pH. The coupled process is more efficient than a single plasma treatment of the polluted liquid in terms of operation cost, waste abatement ratio, and reaction rate. A chemical model involving known plasma generated species and matching acid−base effects is proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901118m [article] Coupling gliding discharge treatment and catalysis by oyster shell powder for pollution abatement of surface waters [texte imprimé] / Estella Njoyim, Auteur ; Paul Ghogomu, Auteur ; Samuel Laminsi, Auteur . - 2010 . - pp. 9773–9780. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9773–9780 Mots-clés : Oyster shell powder Gliding electric discharge Résumé : Adsorption on oyster shell powder (OS) was combined with gliding electric discharge to abate pollution of surface waters sampled in brooks passing through large Cameroonian cities and collecting industrial and domestic wastes. OS powder incorporated into the aqueous samples after exposure to the discharge improved pollutant abatement as compared to the plasma treatment alone. The process kinetics involved pseudo zero-order reactions for treatments longer than 5 min. Total organic carbon linearly decreases with increasing exposure time to the discharge (k ≈ 0.13 mgC L−1 min−1 for a 1 g L−1 standard OS charge). The rate constant linearly increases with the incorporated OS mass, which increases the sample pH. The coupled process is more efficient than a single plasma treatment of the polluted liquid in terms of operation cost, waste abatement ratio, and reaction rate. A chemical model involving known plasma generated species and matching acid−base effects is proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901118m

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Novel carrier of grafted alginate for covalent immobilization of inulinase / Magdy M. M. Elnashar in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9781–9785 Titre : Novel carrier of grafted alginate for covalent immobilization of inulinase Type de document : texte imprimé Auteurs : Magdy M. M. Elnashar, Auteur ; Enas N. Danial, Auteur ; Ghada E. A. Awad, Auteur Année de publication : 2010 Article en page(s) : pp. 9781–9785 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Grafted alginate FTIR techniques DSC Résumé : Inulinase has been extracted from Penicillium chrysogenum P36 and immobilized on a novel matrix of grafted biopolymer. The crude enzyme has been characterized in terms of specific activity, optimum temperature, and temperature stabilities. A novel matrix of alginate modified with polyimines and cross-linked with glutaraldehyde was prepared in beads shape using the Encapsulator to covalently immobilize crude inulinase. The modified beads were characterized using the FTIR and the DSC techniques. The FTIR showed the presence of the aldehydic’s carbonyl group at 1670 cm−1, which differs from that of the carboxylic group at 1620 cm−1. The DSC revealed a significant improvement of the gel’s thermal stability from 200 to 240 °C. The immobilization process improved the enzyme’s optimum temperature from 50 to 55 °C as well as the enzyme’s thermal stability for 2 h at 60 °C with 78% retention of activity as compared to only 7% for the free enzyme. The enzyme’s optimum pH slightly shifted from pH 4.8 for the free enzyme to pH 5 for the immobilized enzyme. However, at pH 5.2−5.5, the enzyme activity improved from 39% for the free enzyme to 75% for the immobilized enzyme. The novel matrix successfully immobilized the inulinase covalently with an enzyme loading capacity of 461 U/g gel. The reusability test proved the durability of the grafted alginate for 20 cycles with retention of 95% of the immobilized enzyme activity, whereas the untreated alginate gel completely dissolved by the eighth use. The results were promising; the grafting method is simple, and immobilization efficiency and enzyme loading capacity could be further improved by optimizing the gel beads’ formulations and the conditions of immobilization for the industrial applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9011276 [article] Novel carrier of grafted alginate for covalent immobilization of inulinase [texte imprimé] / Magdy M. M. Elnashar, Auteur ; Enas N. Danial, Auteur ; Ghada E. A. Awad, Auteur . - 2010 . - pp. 9781–9785. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9781–9785 Mots-clés : Grafted alginate FTIR techniques DSC Résumé : Inulinase has been extracted from Penicillium chrysogenum P36 and immobilized on a novel matrix of grafted biopolymer. The crude enzyme has been characterized in terms of specific activity, optimum temperature, and temperature stabilities. A novel matrix of alginate modified with polyimines and cross-linked with glutaraldehyde was prepared in beads shape using the Encapsulator to covalently immobilize crude inulinase. The modified beads were characterized using the FTIR and the DSC techniques. The FTIR showed the presence of the aldehydic’s carbonyl group at 1670 cm−1, which differs from that of the carboxylic group at 1620 cm−1. The DSC revealed a significant improvement of the gel’s thermal stability from 200 to 240 °C. The immobilization process improved the enzyme’s optimum temperature from 50 to 55 °C as well as the enzyme’s thermal stability for 2 h at 60 °C with 78% retention of activity as compared to only 7% for the free enzyme. The enzyme’s optimum pH slightly shifted from pH 4.8 for the free enzyme to pH 5 for the immobilized enzyme. However, at pH 5.2−5.5, the enzyme activity improved from 39% for the free enzyme to 75% for the immobilized enzyme. The novel matrix successfully immobilized the inulinase covalently with an enzyme loading capacity of 461 U/g gel. The reusability test proved the durability of the grafted alginate for 20 cycles with retention of 95% of the immobilized enzyme activity, whereas the untreated alginate gel completely dissolved by the eighth use. The results were promising; the grafting method is simple, and immobilization efficiency and enzyme loading capacity could be further improved by optimizing the gel beads’ formulations and the conditions of immobilization for the industrial applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9011276

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Participation of electrochemical steps in treating tannery wastewater / C. Ahmed Basha in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9786–9796 Titre : Participation of electrochemical steps in treating tannery wastewater Type de document : texte imprimé Auteurs : C. Ahmed Basha, Auteur ; P. A. Soloman, Auteur ; M. Velan, Auteur Année de publication : 2010 Article en page(s) : pp. 9786–9796 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Tannery wastewater Electrochemically treatement Résumé : The performance of conventional biological treatment of tannery wastewater can be improved by the application of electrochemical treatment to selected streams. In this study, soak liquor, tanning effluent, and post-tanning effluent were electrochemically treated in batch recirculation mode. The experiments were designed, modeled, and optimized using response surface methodology. Considerable removal of chemical oxygen demand (COD, 94.8%) was achieved by treating the soak liquor in a batch recirculation cell under conditions of a circulation flow of 142.8 L h−1, a current density of 5.8 A dm−2, and a time of 7.05 h. Salt remaining in the treated soak liquor was partly utilized in improving the ionic conductivity of the post-tanning effluent for electrochemical treatment. In a separate treatment, the biodegradability index of the post-tanning effluent was improved from 0.3 to 0.67 under conditions of a circulation flow of 112.5 L h−1, a current density of 2.4 A dm−2, and a time of 2.15 h. Considerable reduction in the requirement of reactor volume or residence time of the existing aerated biological treatment system of the total wastewater stream can be achieved by applying such an electrochemical pretreatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900464s [article] Participation of electrochemical steps in treating tannery wastewater [texte imprimé] / C. Ahmed Basha, Auteur ; P. A. Soloman, Auteur ; M. Velan, Auteur . - 2010 . - pp. 9786–9796. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9786–9796 Mots-clés : Tannery wastewater Electrochemically treatement Résumé : The performance of conventional biological treatment of tannery wastewater can be improved by the application of electrochemical treatment to selected streams. In this study, soak liquor, tanning effluent, and post-tanning effluent were electrochemically treated in batch recirculation mode. The experiments were designed, modeled, and optimized using response surface methodology. Considerable removal of chemical oxygen demand (COD, 94.8%) was achieved by treating the soak liquor in a batch recirculation cell under conditions of a circulation flow of 142.8 L h−1, a current density of 5.8 A dm−2, and a time of 7.05 h. Salt remaining in the treated soak liquor was partly utilized in improving the ionic conductivity of the post-tanning effluent for electrochemical treatment. In a separate treatment, the biodegradability index of the post-tanning effluent was improved from 0.3 to 0.67 under conditions of a circulation flow of 112.5 L h−1, a current density of 2.4 A dm−2, and a time of 2.15 h. Considerable reduction in the requirement of reactor volume or residence time of the existing aerated biological treatment system of the total wastewater stream can be achieved by applying such an electrochemical pretreatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900464s

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Formation of highly hydrophobic surfaces on cotton and polyester fabrics using silica sol nanoparticles and nonfluorinated alkylsilane / Qinwen Gao in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9797–9803 Titre : Formation of highly hydrophobic surfaces on cotton and polyester fabrics using silica sol nanoparticles and nonfluorinated alkylsilane Type de document : texte imprimé Auteurs : Qinwen Gao, Auteur ; Quan Zhu, Auteur ; Yuliang Guo, Auteur Année de publication : 2010 Article en page(s) : pp. 9797–9803 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrophobic surfaces Textile fabrics Résumé : Water and soil repellency is one of the most desirable properties for textile fabrics. A surface with a water contact angle higher than 150° is considered to be a practically nonwettable superhydrophobic surface. In this research, we studied the formation of highly hydrophobic surfaces on cotton and polyester fabrics using silica sol formed by hydrolysis and subsequent condensation of tetraethoxysilane under alkaline conditions followed by hydrophobization using hydrolyzed hexadecyltrimethoxysilane (HDTMS). The textile fabrics thus treated showed excellent water repellency with a water contact angle as high as 155° on cotton and 143° on polyester. The high hydrophobicity of the treated fabrics is due to the presence of hydrophobic HDTMS as well as the increase in roughness by silica sol on the surfaces of the treated fabrics. The morphology of the cotton and polyester fabrics were characterized by scanning electron microscopy. We also found that the treated cotton and polyester are resistant to hydrolysis of multiple washing cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005518 [article] Formation of highly hydrophobic surfaces on cotton and polyester fabrics using silica sol nanoparticles and nonfluorinated alkylsilane [texte imprimé] / Qinwen Gao, Auteur ; Quan Zhu, Auteur ; Yuliang Guo, Auteur . - 2010 . - pp. 9797–9803. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9797–9803 Mots-clés : Hydrophobic surfaces Textile fabrics Résumé : Water and soil repellency is one of the most desirable properties for textile fabrics. A surface with a water contact angle higher than 150° is considered to be a practically nonwettable superhydrophobic surface. In this research, we studied the formation of highly hydrophobic surfaces on cotton and polyester fabrics using silica sol formed by hydrolysis and subsequent condensation of tetraethoxysilane under alkaline conditions followed by hydrophobization using hydrolyzed hexadecyltrimethoxysilane (HDTMS). The textile fabrics thus treated showed excellent water repellency with a water contact angle as high as 155° on cotton and 143° on polyester. The high hydrophobicity of the treated fabrics is due to the presence of hydrophobic HDTMS as well as the increase in roughness by silica sol on the surfaces of the treated fabrics. The morphology of the cotton and polyester fabrics were characterized by scanning electron microscopy. We also found that the treated cotton and polyester are resistant to hydrolysis of multiple washing cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005518

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Adsorption of copper acetate onto pretreated activated carbons over a wide concentration range / Amjad Farooq in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9804–9808 Titre : Adsorption of copper acetate onto pretreated activated carbons over a wide concentration range Type de document : texte imprimé Auteurs : Amjad Farooq, Auteur ; Philippe Westreich, Auteur ; Naseem Irfan, Auteur Année de publication : 2010 Article en page(s) : pp. 9804–9808 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Copper acetate Microporous activated carbon Résumé : The commercially available microporous activated carbon Kuraray GC was pretreated in two different ways: one was heated to 950 °C in 5% hydrogen and the other boiled in nitric acid for 5 h. BET surface area measurements and Boehm titrations were done to find the surface area and the numbers of surface functional groups for each carbon. A large range of linearly varying concentrations of aqueous copper acetate solutions was made and stirred with each sample of pretreated carbon. Atomic absorption spectroscopy, titrations, and weight measurements were employed to measure the amount of copper acetate actually adsorbed onto the respective carbon samples. The number of acidic functional groups on the carbon surface as determined by Boehm titrations in the case of the hydrogen treated sample and the nitric acid treated sample do not match with the usual Langmuir parameters both at low and high concentrations. Two distinct isotherm fittings have been obtained for both carbons; double Langmuir isotherms for the hydrogen-treated sample, and a low concentration Langmuir isotherm combined with a high concentration Freundlich isotherm for the nitric acid treated sample. The results have also been compared with the results for untreated Kuraray GC. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900492f [article] Adsorption of copper acetate onto pretreated activated carbons over a wide concentration range [texte imprimé] / Amjad Farooq, Auteur ; Philippe Westreich, Auteur ; Naseem Irfan, Auteur . - 2010 . - pp. 9804–9808. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9804–9808 Mots-clés : Copper acetate Microporous activated carbon Résumé : The commercially available microporous activated carbon Kuraray GC was pretreated in two different ways: one was heated to 950 °C in 5% hydrogen and the other boiled in nitric acid for 5 h. BET surface area measurements and Boehm titrations were done to find the surface area and the numbers of surface functional groups for each carbon. A large range of linearly varying concentrations of aqueous copper acetate solutions was made and stirred with each sample of pretreated carbon. Atomic absorption spectroscopy, titrations, and weight measurements were employed to measure the amount of copper acetate actually adsorbed onto the respective carbon samples. The number of acidic functional groups on the carbon surface as determined by Boehm titrations in the case of the hydrogen treated sample and the nitric acid treated sample do not match with the usual Langmuir parameters both at low and high concentrations. Two distinct isotherm fittings have been obtained for both carbons; double Langmuir isotherms for the hydrogen-treated sample, and a low concentration Langmuir isotherm combined with a high concentration Freundlich isotherm for the nitric acid treated sample. The results have also been compared with the results for untreated Kuraray GC. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900492f

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Thermochemistry of ionic liquid-catalyzed reactions / Sergey P. Verevkin in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9809–9816 Titre : Thermochemistry of ionic liquid-catalyzed reactions : theoretical and experimental study of the beckmann rearrangement—kinetic or thermodynamic control? Type de document : texte imprimé Auteurs : Sergey P. Verevkin, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Alexey V. Tkachev, Auteur Année de publication : 2010 Article en page(s) : pp. 9809–9816 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Beckmann rearrangement reaction Kinetic control Résumé : A thermodynamic analysis of the experimental conditions of the Beckmann rearrangement reaction of oximes into amides has been undertaken to examine whether the reaction is under thermodynamic or kinetic control. To answer this question, the thermodynamic properties of the typical Beckmann rearrangement reactions in the ideal gaseous state—cyclohexanone oxime to caprolactam and 2-butanone oxime to N-methyl-propanamide—were studied by using the quantum mechanical method. Gibbs energy and equilibrium constants of the Beckmann rearrangement have been assessed in the gaseous and the liquid phases. Results of the thermodynamic analysis have shown that Beckmann rearrangements are kinetically controlled. Thus, a search for possible active ionic liquid based catalysts for the mild reaction conditions has been performed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900633r [article] Thermochemistry of ionic liquid-catalyzed reactions : theoretical and experimental study of the beckmann rearrangement—kinetic or thermodynamic control? [texte imprimé] / Sergey P. Verevkin, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Alexey V. Tkachev, Auteur . - 2010 . - pp. 9809–9816. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9809–9816 Mots-clés : Beckmann rearrangement reaction Kinetic control Résumé : A thermodynamic analysis of the experimental conditions of the Beckmann rearrangement reaction of oximes into amides has been undertaken to examine whether the reaction is under thermodynamic or kinetic control. To answer this question, the thermodynamic properties of the typical Beckmann rearrangement reactions in the ideal gaseous state—cyclohexanone oxime to caprolactam and 2-butanone oxime to N-methyl-propanamide—were studied by using the quantum mechanical method. Gibbs energy and equilibrium constants of the Beckmann rearrangement have been assessed in the gaseous and the liquid phases. Results of the thermodynamic analysis have shown that Beckmann rearrangements are kinetically controlled. Thus, a search for possible active ionic liquid based catalysts for the mild reaction conditions has been performed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900633r

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Modeling the effects of color on the UV protection provided by cotton woven fabrics dyed with azo dyestuffs / Ascensión Riva in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9817–9822 Titre : Modeling the effects of color on the UV protection provided by cotton woven fabrics dyed with azo dyestuffs Type de document : texte imprimé Auteurs : Ascensión Riva, Auteur ; Inés Algaba, Auteur ; Montserrat Pepio, Auteur Année de publication : 2010 Article en page(s) : pp. 9817–9822 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Color UV radiation Ultraviolet protection factor Résumé : Color is one of the most influential variables on the protection against ultraviolet radiation provided by a fabric. The protection against UV radiation of a fabric is expressed quantitatively by means of its UPF (ultraviolet protection factor). The present paper shows the results of a study about the influence of the color on the UPF of cotton woven fabrics appropriate for summer articles. Through statistical models, the research seeks to relate the level of protection achieved in dyeing with three azo dyes to the factors governing the process, the shade, and the color intensity, as well as their interaction with the initial UPF of the fabrics. The obtained models will allow the programming and optimization of the value of the UPF of a fabric by means of adequate adjustment of the variables. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006694 [article] Modeling the effects of color on the UV protection provided by cotton woven fabrics dyed with azo dyestuffs [texte imprimé] / Ascensión Riva, Auteur ; Inés Algaba, Auteur ; Montserrat Pepio, Auteur . - 2010 . - pp. 9817–9822. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9817–9822 Mots-clés : Color UV radiation Ultraviolet protection factor Résumé : Color is one of the most influential variables on the protection against ultraviolet radiation provided by a fabric. The protection against UV radiation of a fabric is expressed quantitatively by means of its UPF (ultraviolet protection factor). The present paper shows the results of a study about the influence of the color on the UPF of cotton woven fabrics appropriate for summer articles. Through statistical models, the research seeks to relate the level of protection achieved in dyeing with three azo dyes to the factors governing the process, the shade, and the color intensity, as well as their interaction with the initial UPF of the fabrics. The obtained models will allow the programming and optimization of the value of the UPF of a fabric by means of adequate adjustment of the variables. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006694

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Preparation of biomimetic materials made from polyaspartyl polymer and chitosan for heavy-metal removal / Bo Sun in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9823–9829 Titre : Preparation of biomimetic materials made from polyaspartyl polymer and chitosan for heavy-metal removal Type de document : texte imprimé Auteurs : Bo Sun, Auteur ; Zhen-Tao Mi, Auteur ; Gang An, Auteur Année de publication : 2010 Article en page(s) : pp. 9823–9829 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polyaspartyl polymer Chitosan Peptide−  polysaccharide-resembling structure Résumé : By the combination of polyaspartyl polymer and chitosan, a kind of novel environmentally friendly biomimetic blend material with peptide−polysaccharide-resembling structure was synthesized for heavy-metal removal. The resulting blend possesses diversified functional groups and was further modified by introducing a mercapto group through esterification between thioglycollic acid and hydroxyl group in the structure of chitosan. The polyaspartyl polymer−chitosan blend with 2.2 wt % mercapto group content improves the adsorption of organic compounds of mercury and arsenic. The blend exhibits a lower swelling behavior in the presence of water and is verified to have a potential biodegradability by elemental analysis and infrared spectrum (FT-IR). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900673h [article] Preparation of biomimetic materials made from polyaspartyl polymer and chitosan for heavy-metal removal [texte imprimé] / Bo Sun, Auteur ; Zhen-Tao Mi, Auteur ; Gang An, Auteur . - 2010 . - pp. 9823–9829. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9823–9829 Mots-clés : Polyaspartyl polymer Chitosan Peptide−  polysaccharide-resembling structure Résumé : By the combination of polyaspartyl polymer and chitosan, a kind of novel environmentally friendly biomimetic blend material with peptide−polysaccharide-resembling structure was synthesized for heavy-metal removal. The resulting blend possesses diversified functional groups and was further modified by introducing a mercapto group through esterification between thioglycollic acid and hydroxyl group in the structure of chitosan. The polyaspartyl polymer−chitosan blend with 2.2 wt % mercapto group content improves the adsorption of organic compounds of mercury and arsenic. The blend exhibits a lower swelling behavior in the presence of water and is verified to have a potential biodegradability by elemental analysis and infrared spectrum (FT-IR). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900673h

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Bleaching miscanthus x giganteus acetosolv pulps with a new totally chlorine-free sequence and the effect of carbohydrate protectors / Juan Jose Villaverde in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9830–9836 Titre : Bleaching miscanthus x giganteus acetosolv pulps with a new totally chlorine-free sequence and the effect of carbohydrate protectors Type de document : texte imprimé Auteurs : Juan Jose Villaverde, Auteur ; Pablo Ligero, Auteur ; Alberto De Vega, Auteur Année de publication : 2010 Article en page(s) : pp. 9830–9836 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Semibleached Miscanthus x giganteus Acetosolv pulp Alkaline treatmentPeroxyacetate treatment Résumé : The bleaching of semibleached Miscanthus x giganteus Acetosolv pulp, after alkaline and peroxyacetate treatments, was investigated by a novel totally chlorine-free (TCF) sequence. Oxygen delignification (O-stage), peroxide (P-stage), and oxygen-pressurized hydrogen peroxide stage (PO-stage) were assayed in order to reach the target values for dissolving pulps. Using factorial experimental designs, we investigated the effects of the bleaching variables on the parameters defining the process and checked the effects after adding chelating agents. Regression equations satisfactorily fitted the experimental results, and under the optimum conditions, a fully bleached pulp (86.9% ISO brightness) with a viscosity of 786 cm3/g and a very favorable kappa number (1.3) was obtained. Carbohydrate protectors substantially improved the characteristics of dissolving pulps, but pulps with kappa values above 6 did not improve with carbohydrate protectors as expected. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008277 [article] Bleaching miscanthus x giganteus acetosolv pulps with a new totally chlorine-free sequence and the effect of carbohydrate protectors [texte imprimé] / Juan Jose Villaverde, Auteur ; Pablo Ligero, Auteur ; Alberto De Vega, Auteur . - 2010 . - pp. 9830–9836. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9830–9836 Mots-clés : Semibleached Miscanthus x giganteus Acetosolv pulp Alkaline treatmentPeroxyacetate treatment Résumé : The bleaching of semibleached Miscanthus x giganteus Acetosolv pulp, after alkaline and peroxyacetate treatments, was investigated by a novel totally chlorine-free (TCF) sequence. Oxygen delignification (O-stage), peroxide (P-stage), and oxygen-pressurized hydrogen peroxide stage (PO-stage) were assayed in order to reach the target values for dissolving pulps. Using factorial experimental designs, we investigated the effects of the bleaching variables on the parameters defining the process and checked the effects after adding chelating agents. Regression equations satisfactorily fitted the experimental results, and under the optimum conditions, a fully bleached pulp (86.9% ISO brightness) with a viscosity of 786 cm3/g and a very favorable kappa number (1.3) was obtained. Carbohydrate protectors substantially improved the characteristics of dissolving pulps, but pulps with kappa values above 6 did not improve with carbohydrate protectors as expected. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008277

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Formation of tarry material from 5-HMF in subcritical and supercritical water / Athika Chuntanapum in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9837–9846 Titre : Formation of tarry material from 5-HMF in subcritical and supercritical water Type de document : texte imprimé Auteurs : Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur Année de publication : 2010 Article en page(s) : pp. 9837–9846 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Compound 5-hydroxymethylfurfural Biomass Tarry material Résumé : The compound 5-hydroxymethylfurfural (5-HMF) is thought to be an intermediate for the formation of tarry material in the supercritical water gasification (SCWG) of biomass. To gain insight on the formation mechanism of tarry material, we examined 5-HMF under both subcritical and supercritical conditions. The experiments of this study were conducted in a continuous reactor designed for an instant heating of 5-HMF solution to the reaction temperature. The reaction temperatures were set at 350 and 450 °C, and the pressure was set at 25 MPa. The initial concentration of 5-HMF and the residence time were adjusted in the range of 0.02−0.15 M (at room temperature) and 80−3000 s, respectively. The formation of char particles was only observed under the subcritical conditions. Char yield increased as the initial concentration of 5-HMF rose, with a reaction order of 4.29, with respect to 5-HMF concentration. The liquid products obtained from the 5-HMF decomposition also contributed to the polymerization to form char, with a reaction order of 1.21, based on their concentration. The sensitivity analysis indicated the high sensitivity of reaction orders on the char yield. The liquid products were identified by liquid chromatography/mass spectroscopy (LC/MS) and high-performance liquid chromatography (HPLC). The char particles were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectrometry. The char characterization results implied that the char particles formed had a polyaromatic structure. Based on our experimental findings, we proposed a mechanism of char particle formation from 5-HMF. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900423g [article] Formation of tarry material from 5-HMF in subcritical and supercritical water [texte imprimé] / Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur . - 2010 . - pp. 9837–9846. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9837–9846 Mots-clés : Compound 5-hydroxymethylfurfural Biomass Tarry material Résumé : The compound 5-hydroxymethylfurfural (5-HMF) is thought to be an intermediate for the formation of tarry material in the supercritical water gasification (SCWG) of biomass. To gain insight on the formation mechanism of tarry material, we examined 5-HMF under both subcritical and supercritical conditions. The experiments of this study were conducted in a continuous reactor designed for an instant heating of 5-HMF solution to the reaction temperature. The reaction temperatures were set at 350 and 450 °C, and the pressure was set at 25 MPa. The initial concentration of 5-HMF and the residence time were adjusted in the range of 0.02−0.15 M (at room temperature) and 80−3000 s, respectively. The formation of char particles was only observed under the subcritical conditions. Char yield increased as the initial concentration of 5-HMF rose, with a reaction order of 4.29, with respect to 5-HMF concentration. The liquid products obtained from the 5-HMF decomposition also contributed to the polymerization to form char, with a reaction order of 1.21, based on their concentration. The sensitivity analysis indicated the high sensitivity of reaction orders on the char yield. The liquid products were identified by liquid chromatography/mass spectroscopy (LC/MS) and high-performance liquid chromatography (HPLC). The char particles were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectrometry. The char characterization results implied that the char particles formed had a polyaromatic structure. Based on our experimental findings, we proposed a mechanism of char particle formation from 5-HMF. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900423g

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Adsorption and desorption of SOx on diesel oxidation catalysts / Oliver Krocher in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9847–9857 Titre : Adsorption and desorption of SOx on diesel oxidation catalysts Type de document : texte imprimé Auteurs : Oliver Krocher, Auteur ; Markus Widmer, Auteur ; Martin Elsener, Auteur Année de publication : 2010 Article en page(s) : pp. 9847–9857 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : NO oxidation SO2Diesel catalysts Résumé : The deactivation of NO oxidation by SO2 was studied with the use of commercial diesel oxidation catalysts (DOC) and Pt/Al2O3 as reference material, coated on cordierite monolith. Despite their slightly different elemental compositions, the NO conversion rates of the fresh commercial catalysts were very similar. The maximum NO conversion was 38% at 350 °C, and above this temperature conversion started to be limited by the thermodynamics of the reaction. The rates of NO conversion strongly decreased with the start of SO2 dosing. For analysis of SO2 conversion and uptake, SO2 and SO3/H2SO4 were determined separately in the gas phase by absorption and titration. Under typical exhaust gas conditions (1 ppm SO2, 250 °C), the catalysts functioned as sulfur traps and stored a large part of the emitted SO2. The SOx storage was divided into two phases: a fast saturation of the catalyst surface with sulfuric acid, which hampered NO conversion, and a slow, long-lasting sulfation of the washcoat. The storage capacities of the oxidation catalysts reached their maxima at 250 °C due to the temperature dependency of sulfur adsorption and desorption. Adsorbed sulfuric acid desorbed between 350 and 400 °C, whereas more stable compounds, such as aluminum sulfate, were decomposed at higher temperatures. Deactivated catalysts could be completely regenerated within a few minutes at temperatures above 350 °C. However, repeated or lengthier thermal treatments resulted in a reduced sulfur storage capacity and irreversible activity losses for NO oxidation due to a reduction of the active surface by sintering. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900882p [article] Adsorption and desorption of SOx on diesel oxidation catalysts [texte imprimé] / Oliver Krocher, Auteur ; Markus Widmer, Auteur ; Martin Elsener, Auteur . - 2010 . - pp. 9847–9857. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9847–9857 Mots-clés : NO oxidation SO2Diesel catalysts Résumé : The deactivation of NO oxidation by SO2 was studied with the use of commercial diesel oxidation catalysts (DOC) and Pt/Al2O3 as reference material, coated on cordierite monolith. Despite their slightly different elemental compositions, the NO conversion rates of the fresh commercial catalysts were very similar. The maximum NO conversion was 38% at 350 °C, and above this temperature conversion started to be limited by the thermodynamics of the reaction. The rates of NO conversion strongly decreased with the start of SO2 dosing. For analysis of SO2 conversion and uptake, SO2 and SO3/H2SO4 were determined separately in the gas phase by absorption and titration. Under typical exhaust gas conditions (1 ppm SO2, 250 °C), the catalysts functioned as sulfur traps and stored a large part of the emitted SO2. The SOx storage was divided into two phases: a fast saturation of the catalyst surface with sulfuric acid, which hampered NO conversion, and a slow, long-lasting sulfation of the washcoat. The storage capacities of the oxidation catalysts reached their maxima at 250 °C due to the temperature dependency of sulfur adsorption and desorption. Adsorbed sulfuric acid desorbed between 350 and 400 °C, whereas more stable compounds, such as aluminum sulfate, were decomposed at higher temperatures. Deactivated catalysts could be completely regenerated within a few minutes at temperatures above 350 °C. However, repeated or lengthier thermal treatments resulted in a reduced sulfur storage capacity and irreversible activity losses for NO oxidation due to a reduction of the active surface by sintering. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900882p

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Importance of biomass particle size in structural evolution and reactivity of char in steam gasification / Mohammad Asadullah in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9858–9863 Titre : Importance of biomass particle size in structural evolution and reactivity of char in steam gasification Type de document : texte imprimé Auteurs : Mohammad Asadullah, Auteur ; Shu Zhang, Auteur ; Zhenhua Min, Auteur Année de publication : 2010 Article en page(s) : pp. 9858–9863 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chars Combustion reactivity Alkali and alkaline earth metallic Résumé : An Australian mallee wood of different particle sizes was gasified in steam in a fluidized-bed reactor at different temperatures. The structural features of chars, combustion reactivity of chars, and alkali and alkaline earth metallic (AAEM) species retention in chars were investigated in view to elucidate how the particle size affects the carbon conversion during steam gasification of biomass. The structural features and combustion reactivity of chars were investigated using Raman spectroscopy and thermogravimetric anlysis, respectively. The Raman intensity and combustion reactivity of chars were seen to decrease with increasing temperature. However, the combustion reactivity of char increased with increasing biomass particle size in the bigger particle range (1.5−5.18 mm). This is due mainly to the increase of catalytic species (AAEM) retention in chars. The increased AAEM retention and condensation of aromatic ring systems are a result of increasing mass transfer resistance in bigger particles of biomass. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901214z [article] Importance of biomass particle size in structural evolution and reactivity of char in steam gasification [texte imprimé] / Mohammad Asadullah, Auteur ; Shu Zhang, Auteur ; Zhenhua Min, Auteur . - 2010 . - pp. 9858–9863. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9858–9863 Mots-clés : Chars Combustion reactivity Alkali and alkaline earth metallic Résumé : An Australian mallee wood of different particle sizes was gasified in steam in a fluidized-bed reactor at different temperatures. The structural features of chars, combustion reactivity of chars, and alkali and alkaline earth metallic (AAEM) species retention in chars were investigated in view to elucidate how the particle size affects the carbon conversion during steam gasification of biomass. The structural features and combustion reactivity of chars were investigated using Raman spectroscopy and thermogravimetric anlysis, respectively. The Raman intensity and combustion reactivity of chars were seen to decrease with increasing temperature. However, the combustion reactivity of char increased with increasing biomass particle size in the bigger particle range (1.5−5.18 mm). This is due mainly to the increase of catalytic species (AAEM) retention in chars. The increased AAEM retention and condensation of aromatic ring systems are a result of increasing mass transfer resistance in bigger particles of biomass. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901214z

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Energy efficiency in photocatalytic reactors for the full span of reaction times / Benito Serrano in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9864–9876 Titre : Energy efficiency in photocatalytic reactors for the full span of reaction times Type de document : texte imprimé Auteurs : Benito Serrano, Auteur ; Aaron Ortiz, Auteur ; Jesus Moreira, Auteur Année de publication : 2010 Article en page(s) : pp. 9864–9876 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Photocatalytic reactors Kinetic modeling Parallel−  series reaction network Résumé : OH• radicals react in photocatalytic reactors via adsorbed species on the catalytic surface through complex reaction mechanisms leading to complete mineralization of organic molecules. Our research group has recently contributed with kinetic modeling of the photocatalytic network using a parallel−series reaction network. This kinetic approach helps toward the assessment of the photocatalytic thermodynamic efficiency factors (PTEF) and quantum yields (QY). Efficiency calculations consider stoichiometric relationships involving observable chemical species and OH• groups. These stoichiometric equations set the OH• requirements for reaching a particular intermediate species and for the complete mineralization of them. On this basis, the PTEF and QY factors for phenol photoconversion point toward a high degree of photon utilization as in the case of Photo-CREC units and, as a result, confirm the value of photocatalysis for the conversion of organic pollutants in water. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900353n [article] Energy efficiency in photocatalytic reactors for the full span of reaction times [texte imprimé] / Benito Serrano, Auteur ; Aaron Ortiz, Auteur ; Jesus Moreira, Auteur . - 2010 . - pp. 9864–9876. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9864–9876 Mots-clés : Photocatalytic reactors Kinetic modeling Parallel−  series reaction network Résumé : OH• radicals react in photocatalytic reactors via adsorbed species on the catalytic surface through complex reaction mechanisms leading to complete mineralization of organic molecules. Our research group has recently contributed with kinetic modeling of the photocatalytic network using a parallel−series reaction network. This kinetic approach helps toward the assessment of the photocatalytic thermodynamic efficiency factors (PTEF) and quantum yields (QY). Efficiency calculations consider stoichiometric relationships involving observable chemical species and OH• groups. These stoichiometric equations set the OH• requirements for reaching a particular intermediate species and for the complete mineralization of them. On this basis, the PTEF and QY factors for phenol photoconversion point toward a high degree of photon utilization as in the case of Photo-CREC units and, as a result, confirm the value of photocatalysis for the conversion of organic pollutants in water. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900353n

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Kinetic characterization of xylose monomer and oligomer concentrations during dilute acid pretreatment of lignocellulosic biomass from forests and switchgrass / Juan E. Morinelly in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9877–9884 Titre : Kinetic characterization of xylose monomer and oligomer concentrations during dilute acid pretreatment of lignocellulosic biomass from forests and switchgrass Type de document : texte imprimé Auteurs : Juan E. Morinelly, Auteur ; Jill R. Jensen, Auteur ; Matthew Browne, Auteur Année de publication : 2010 Article en page(s) : pp. 9877–9884 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Xylose monomer Kinetic model Oligomer concentrations Résumé : The kinetics of dilute acid hydrolysis for aspen, balsam, and switchgrass were investigated at various temperatures, acid concentrations, and reaction times using small-scale isothermal tubular reactors. The experimental data was fitted to a four-step kinetic model with first-order irreversible rate constants at each step. The maximum yields of xylose monomer for aspen and balsam show limited variability with changing reaction severity with maximum levels of approximately 85% and 67% of initial xylan, respectively. Switchgrass xylose monomer yields varied significantly with very low yields observed at 0.25 wt % acid (32% of initial xylan) and relatively high yields at 0.75 wt % acid (81% of initial xylan). The measured furfural levels at the point where xylose monomer is maximized, relative to initial xylan, range from 1% to 6% for aspen and balsam, and 3% to 15% for switchgrass. Excellent agreement, both quantitatively and qualitatively, is shown between the experimental monomer data and its model fit. Although the maximum xylose oligomer concentrations and the initial concentrations during oligomer formation are accurately predicted, the model with irreversible kinetic constants does not describe the oligomer data accurately at long times. The model predicts furfural levels comparable to those measured; however, the model overpredicts early data points and underpredicts late data points. Arrhenius kinetic parameters were derived for all three species at each step of the proposed model and these parameters were of the same order as literature values. Preliminary results in regards to the effect of aspen solids loading on reaction kinetics show that a 50% decrease in solids loading (10% to 5%) results in faster rates of reaction. This is particularly apparent for the degradation of xylose monomer which increases by a factor of almost 3. Several recommendations to improve the modeling of dilute acid hydrolysis reactions are discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900793p [article] Kinetic characterization of xylose monomer and oligomer concentrations during dilute acid pretreatment of lignocellulosic biomass from forests and switchgrass [texte imprimé] / Juan E. Morinelly, Auteur ; Jill R. Jensen, Auteur ; Matthew Browne, Auteur . - 2010 . - pp. 9877–9884. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9877–9884 Mots-clés : Xylose monomer Kinetic model Oligomer concentrations Résumé : The kinetics of dilute acid hydrolysis for aspen, balsam, and switchgrass were investigated at various temperatures, acid concentrations, and reaction times using small-scale isothermal tubular reactors. The experimental data was fitted to a four-step kinetic model with first-order irreversible rate constants at each step. The maximum yields of xylose monomer for aspen and balsam show limited variability with changing reaction severity with maximum levels of approximately 85% and 67% of initial xylan, respectively. Switchgrass xylose monomer yields varied significantly with very low yields observed at 0.25 wt % acid (32% of initial xylan) and relatively high yields at 0.75 wt % acid (81% of initial xylan). The measured furfural levels at the point where xylose monomer is maximized, relative to initial xylan, range from 1% to 6% for aspen and balsam, and 3% to 15% for switchgrass. Excellent agreement, both quantitatively and qualitatively, is shown between the experimental monomer data and its model fit. Although the maximum xylose oligomer concentrations and the initial concentrations during oligomer formation are accurately predicted, the model with irreversible kinetic constants does not describe the oligomer data accurately at long times. The model predicts furfural levels comparable to those measured; however, the model overpredicts early data points and underpredicts late data points. Arrhenius kinetic parameters were derived for all three species at each step of the proposed model and these parameters were of the same order as literature values. Preliminary results in regards to the effect of aspen solids loading on reaction kinetics show that a 50% decrease in solids loading (10% to 5%) results in faster rates of reaction. This is particularly apparent for the degradation of xylose monomer which increases by a factor of almost 3. Several recommendations to improve the modeling of dilute acid hydrolysis reactions are discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900793p

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Effect of magnesium addition to PtSnNa/ZSM-5 on the catalytic properties in the dehydrogenation of propane / Linyang Bai in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9885–9891 Titre : Effect of magnesium addition to PtSnNa/ZSM-5 on the catalytic properties in the dehydrogenation of propane Type de document : texte imprimé Auteurs : Linyang Bai, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 9885–9891 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Magnesium addition Propane dehydrogenation Résumé : The effect of Mg addition to PtSnNa/ZSM-5 on the catalytic properties in propane dehydrogenation was investigated. The catalysts were characterized by using different techniques: XRD, BET, TEM, NH3-TPD, XPS, TPO, and TG-DTA. Results indicate that the presence of magnesium not only modifies the acid function and the structure of metallic phase but also diminishes carbon deposition on the catalyst. Among the catalysts studied, the PtSnNaMg(0.5%)/ZSM-5 exhibits the best performance in terms of propane conversion and stability. The high catalytic performance may be due to the strong interaction between Pt and Sn. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900534m [article] Effect of magnesium addition to PtSnNa/ZSM-5 on the catalytic properties in the dehydrogenation of propane [texte imprimé] / Linyang Bai, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur . - 2010 . - pp. 9885–9891. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9885–9891 Mots-clés : Magnesium addition Propane dehydrogenation Résumé : The effect of Mg addition to PtSnNa/ZSM-5 on the catalytic properties in propane dehydrogenation was investigated. The catalysts were characterized by using different techniques: XRD, BET, TEM, NH3-TPD, XPS, TPO, and TG-DTA. Results indicate that the presence of magnesium not only modifies the acid function and the structure of metallic phase but also diminishes carbon deposition on the catalyst. Among the catalysts studied, the PtSnNaMg(0.5%)/ZSM-5 exhibits the best performance in terms of propane conversion and stability. The high catalytic performance may be due to the strong interaction between Pt and Sn. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900534m

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Kinetics of the acid digestion of serpentine with concurrent grinding. 2. detailed investigation and model development / Van Essendelft, Dirk T. in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9892–9901 Titre : Kinetics of the acid digestion of serpentine with concurrent grinding. 2. detailed investigation and model development Type de document : texte imprimé Auteurs : Van Essendelft, Dirk T., Auteur ; Schobert, Harold H., Auteur Année de publication : 2010 Article en page(s) : pp. 9892–9901 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Magnesium Serpentine Mineral carbonation methodology Résumé : The rapid extraction of magnesium from serpentine is critical to novel low-pressure mineral carbonation methodology. Though almost any acid can dissolve the magnesium, the rate plays a critical role in the industrialization of the process. It has been demonstrated that including a low-energy, attrition-type grinding with the chemical attack of the acid can more than double the extraction rate. In part 1 of this investigation, it was found that a model that accounts for surface reaction, surface speciation, the electrical double layer, particle size distribution, and ash layer diffusion can adequately describe the kinetics of the dissolution of serpentine with concurrent grinding. However, the model did not account for changes in temperature, concentration, and grinding energy input. We report here the model developments and changes as well as a detailed experimental investigation to provide validation for the model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005832 [article] Kinetics of the acid digestion of serpentine with concurrent grinding. 2. detailed investigation and model development [texte imprimé] / Van Essendelft, Dirk T., Auteur ; Schobert, Harold H., Auteur . - 2010 . - pp. 9892–9901. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9892–9901 Mots-clés : Magnesium Serpentine Mineral carbonation methodology Résumé : The rapid extraction of magnesium from serpentine is critical to novel low-pressure mineral carbonation methodology. Though almost any acid can dissolve the magnesium, the rate plays a critical role in the industrialization of the process. It has been demonstrated that including a low-energy, attrition-type grinding with the chemical attack of the acid can more than double the extraction rate. In part 1 of this investigation, it was found that a model that accounts for surface reaction, surface speciation, the electrical double layer, particle size distribution, and ash layer diffusion can adequately describe the kinetics of the dissolution of serpentine with concurrent grinding. However, the model did not account for changes in temperature, concentration, and grinding energy input. We report here the model developments and changes as well as a detailed experimental investigation to provide validation for the model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005832

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Wet oxidation of thiocyanate under different pH conditions / Sergio Collado in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9902–9909 Titre : Wet oxidation of thiocyanate under different pH conditions : kinetics and mechanistic analysis Type de document : texte imprimé Auteurs : Sergio Collado, Auteur ; Adriana Laca, Auteur ; Mario Díaz, Auteur Année de publication : 2010 Article en page(s) : pp. 9902–9909 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Thiocyanate Wet oxidation Résumé : The wet oxidation of thiocyanate has been investigated in a 1-L semibatch reactor at temperatures in the range of 438.15−468.15 K and total pressures between 2.0 × 103 kPa and 8.1 × 103 kPa. The initial pH value of the reaction media was varied between pH 2 and pH 12 and was found to be a key parameter in the rate of thiocyanate degradation. The evolution of concentration of substrate and products (sulfate and ammonium) were analyzed. Based on the experimental data and bibliography information, a kinetic model was obtained and, here, possible pathways, depending on the initial pH of the media, are suggested for thiocyanate oxidation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006485 [article] Wet oxidation of thiocyanate under different pH conditions : kinetics and mechanistic analysis [texte imprimé] / Sergio Collado, Auteur ; Adriana Laca, Auteur ; Mario Díaz, Auteur . - 2010 . - pp. 9902–9909. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9902–9909 Mots-clés : Thiocyanate Wet oxidation Résumé : The wet oxidation of thiocyanate has been investigated in a 1-L semibatch reactor at temperatures in the range of 438.15−468.15 K and total pressures between 2.0 × 103 kPa and 8.1 × 103 kPa. The initial pH value of the reaction media was varied between pH 2 and pH 12 and was found to be a key parameter in the rate of thiocyanate degradation. The evolution of concentration of substrate and products (sulfate and ammonium) were analyzed. Based on the experimental data and bibliography information, a kinetic model was obtained and, here, possible pathways, depending on the initial pH of the media, are suggested for thiocyanate oxidation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006485

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Intrinsic kinetics of catalytic hydrogenation of cardanol / Zhi-Bo Mao in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9910–9914 Titre : Intrinsic kinetics of catalytic hydrogenation of cardanol Type de document : texte imprimé Auteurs : Zhi-Bo Mao, Auteur ; Ting-Liang Luo, Auteur ; Hong-Tao Cheng, Auteur Année de publication : 2010 Article en page(s) : pp. 9910–9914 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cardanol Catalytic hydrogenation Raney nickel catalyst Résumé : The experiment of catalytic hydrogenation of cardanol was performed on a Raney nickel catalyst for the purpose of eliminating the effects of internal and external diffusion. The kinetics data have been collected experimentally over ranges of 2.5−4 MPa and 373.15−393.15 K, respectively. Then, the intrinsic kinetics of the catalytic hydrogenation reaction of cardanol was studied. It was proven that the catalytic hydrogenation of cardanol is a second-order irreversible series-parallel reaction under the experimental conditions. The kinetic parameters (Ea, K0) and kinetic equation were obtained through fitting, and the kinetic model was proven through testing to be reliable. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900655a [article] Intrinsic kinetics of catalytic hydrogenation of cardanol [texte imprimé] / Zhi-Bo Mao, Auteur ; Ting-Liang Luo, Auteur ; Hong-Tao Cheng, Auteur . - 2010 . - pp. 9910–9914. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9910–9914 Mots-clés : Cardanol Catalytic hydrogenation Raney nickel catalyst Résumé : The experiment of catalytic hydrogenation of cardanol was performed on a Raney nickel catalyst for the purpose of eliminating the effects of internal and external diffusion. The kinetics data have been collected experimentally over ranges of 2.5−4 MPa and 373.15−393.15 K, respectively. Then, the intrinsic kinetics of the catalytic hydrogenation reaction of cardanol was studied. It was proven that the catalytic hydrogenation of cardanol is a second-order irreversible series-parallel reaction under the experimental conditions. The kinetic parameters (Ea, K0) and kinetic equation were obtained through fitting, and the kinetic model was proven through testing to be reliable. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900655a

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Degradation of methylene blue by heterogeneous fenton reaction using titanomagnetite at neutral pH values / Shijian Yang in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9915–9921 Titre : Degradation of methylene blue by heterogeneous fenton reaction using titanomagnetite at neutral pH values : process and affecting factors Type de document : texte imprimé Auteurs : Shijian Yang, Auteur ; Hongping He, Auteur ; Daqing Wu, Auteur Année de publication : 2010 Article en page(s) : pp. 9915–9921 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Titanomagnetite Methylene blue Résumé : In this work, titanomagnetite was used as a heterogeneous Fenton catalyst for the degradation of methylene blue (MB). The degradation of MB on synthetic titanomagnetite at neutral pH values was studied in comparison with the adsorption of MB on titanomagnetite using UV−vis, FTIR, and the analyses of element C on titanomagnetite and DOC in reaction solution. Meanwhile, important factors affecting catalytic activity were investigated, that is, titanomagnetite load, H2O2 concentration, and reaction temperature. Titanomagnetite decomposed H2O2 yielding highly reactive hydroxyl radicals, and MB adsorbed on titanomagnetite was degraded. With the increases of titanomagnetite load, H2O2 concentration, and reaction temperature, the degradation of MB was promoted. Moreover, titanomagnetite was proved to be durable with a stable MB removal efficiency after five consecutive cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900666b [article] Degradation of methylene blue by heterogeneous fenton reaction using titanomagnetite at neutral pH values : process and affecting factors [texte imprimé] / Shijian Yang, Auteur ; Hongping He, Auteur ; Daqing Wu, Auteur . - 2010 . - pp. 9915–9921. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9915–9921 Mots-clés : Titanomagnetite Methylene blue Résumé : In this work, titanomagnetite was used as a heterogeneous Fenton catalyst for the degradation of methylene blue (MB). The degradation of MB on synthetic titanomagnetite at neutral pH values was studied in comparison with the adsorption of MB on titanomagnetite using UV−vis, FTIR, and the analyses of element C on titanomagnetite and DOC in reaction solution. Meanwhile, important factors affecting catalytic activity were investigated, that is, titanomagnetite load, H2O2 concentration, and reaction temperature. Titanomagnetite decomposed H2O2 yielding highly reactive hydroxyl radicals, and MB adsorbed on titanomagnetite was degraded. With the increases of titanomagnetite load, H2O2 concentration, and reaction temperature, the degradation of MB was promoted. Moreover, titanomagnetite was proved to be durable with a stable MB removal efficiency after five consecutive cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900666b

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Steam-generating composite sheets prepared using techniques in the papermaking process. 1. effective retention of iron powder in a sheet using fibrillated cellulose fibers / Yoshiaki Kumamoto in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9922–9929 Titre : Steam-generating composite sheets prepared using techniques in the papermaking process. 1. effective retention of iron powder in a sheet using fibrillated cellulose fibers Type de document : texte imprimé Auteurs : Yoshiaki Kumamoto, Auteur ; Masataka Ishikawa, Auteur ; Hironobu Kawajiri, Auteur Année de publication : 2010 Article en page(s) : pp. 9922–9929 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Flexible heat- and steam-generating sheets Iron powder Résumé : Flexible heat- and steam-generating sheets are promising medical devices for human healthcare, and oxidation of iron powder in sheets has potential applications for this purpose. Hence, the preparation conditions of composite sheets containing iron powder, cellulose fiber and activated carbon powder using techniques in the papermaking process were investigated to increase the iron powder content as much as possible and improve retention ratios of iron powder in the sheets. When unfibrillated cellulose fibers were used without any retention aids, the total retention ratios of the components were less than 40%. By contrast, when highly fibrillated cellulose fibers were used in combination with a cationic/anionic dual polymer system, the total retention ratios at a basis weight of 217 g m−2 reached about 90%. Moreover, iron powder aggregates in the sheet surfaces as well as throughout the thickness of the sheet, and higher tensile and internal strengths were obtained by using highly fibrillated cellulose fibers. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900875u [article] Steam-generating composite sheets prepared using techniques in the papermaking process. 1. effective retention of iron powder in a sheet using fibrillated cellulose fibers [texte imprimé] / Yoshiaki Kumamoto, Auteur ; Masataka Ishikawa, Auteur ; Hironobu Kawajiri, Auteur . - 2010 . - pp. 9922–9929. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9922–9929 Mots-clés : Flexible heat- and steam-generating sheets Iron powder Résumé : Flexible heat- and steam-generating sheets are promising medical devices for human healthcare, and oxidation of iron powder in sheets has potential applications for this purpose. Hence, the preparation conditions of composite sheets containing iron powder, cellulose fiber and activated carbon powder using techniques in the papermaking process were investigated to increase the iron powder content as much as possible and improve retention ratios of iron powder in the sheets. When unfibrillated cellulose fibers were used without any retention aids, the total retention ratios of the components were less than 40%. By contrast, when highly fibrillated cellulose fibers were used in combination with a cationic/anionic dual polymer system, the total retention ratios at a basis weight of 217 g m−2 reached about 90%. Moreover, iron powder aggregates in the sheet surfaces as well as throughout the thickness of the sheet, and higher tensile and internal strengths were obtained by using highly fibrillated cellulose fibers. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900875u

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Steam-generating composite sheets prepared using techniques in the papermaking process. 2. relationships between sheet structures and steam-generation behavior / Yoshiaki Kumamoto in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9930–9935 Titre : Steam-generating composite sheets prepared using techniques in the papermaking process. 2. relationships between sheet structures and steam-generation behavior Type de document : texte imprimé Auteurs : Yoshiaki Kumamoto, Auteur ; Masataka Ishikawa, Auteur ; Hironobu Kawajiri, Auteur Année de publication : 2010 Article en page(s) : pp. 9930–9935 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sheet structures Steam-generation Résumé : Steam-generating sheets for disposable body warmers were prepared using techniques in papermaking processes, from slurries of iron powder, fibrillated cellulose fiber, and activated carbon powder with various weight ratios. Heat generation behavior of the composite sheets was compared with mat-formed samples. Composite sheets with the iron powder:cellulose fiber:activated carbon powder weight ratio of 86:6:8 had suitable heat generation temperatures in the range 40−42 °C and the longest duration time (>10 h), when exposed to air in the presence of 5% NaCl. On the basis of the results, a performance diagram relating the duration time at temperatures higher than 40 °C to the weight ratios of the three components was obtained. The steam-generation behavior of the composite sheets was superior to that of mat samples in terms of steam-generation rates, duration time, and other properties. After steam generation, the sheets became harder and stiffer than the original sheets through formation of fused iron oxide layers covering the sheet surfaces. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900876s [article] Steam-generating composite sheets prepared using techniques in the papermaking process. 2. relationships between sheet structures and steam-generation behavior [texte imprimé] / Yoshiaki Kumamoto, Auteur ; Masataka Ishikawa, Auteur ; Hironobu Kawajiri, Auteur . - 2010 . - pp. 9930–9935. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9930–9935 Mots-clés : Sheet structures Steam-generation Résumé : Steam-generating sheets for disposable body warmers were prepared using techniques in papermaking processes, from slurries of iron powder, fibrillated cellulose fiber, and activated carbon powder with various weight ratios. Heat generation behavior of the composite sheets was compared with mat-formed samples. Composite sheets with the iron powder:cellulose fiber:activated carbon powder weight ratio of 86:6:8 had suitable heat generation temperatures in the range 40−42 °C and the longest duration time (>10 h), when exposed to air in the presence of 5% NaCl. On the basis of the results, a performance diagram relating the duration time at temperatures higher than 40 °C to the weight ratios of the three components was obtained. The steam-generation behavior of the composite sheets was superior to that of mat samples in terms of steam-generation rates, duration time, and other properties. After steam generation, the sheets became harder and stiffer than the original sheets through formation of fused iron oxide layers covering the sheet surfaces. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900876s

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Enhancement of the meltdown temperature of a lithium ion battery separator via a nanocomposite coating / S. H. Yoo in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9936–9941 Titre : Enhancement of the meltdown temperature of a lithium ion battery separator via a nanocomposite coating Type de document : texte imprimé Auteurs : S. H. Yoo, Auteur ; C. K. Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 9936–9941 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Lithium ion battery separator Meltdown temperature Résumé : In a previous study, a lithium ion battery separator was coated with polymers synthesized from various ethylene glycol dimethacrylates to enhance its meltdown temperature. The meltdown temperature of the separator was increased to 155 °C when it was coated with polymer synthesized from diethylene glycol dimethacrylate (DEGDMA). In this study, a PE separator was coated with nanocomposites composed of DEGDMA polymer and silica nanoparticles for further enhancement of the meltdown temperature. Coatings with nanocomposites were prepared via two different methods: coating the separator by reacting a methanol solution containing DEGDMA and silica nanoparticles or coating the separator by reacting with a methanol solution containing water, DEGDMA, and tetraethylorthosilicate. The formation of nanocomposite on the separator was confirmed by FT-IR, EDS, and electron microscopy. Regardless of the coating method, an increase in the meltdown temperature with a decrease in the air permeability was observed with the nanocomposite coating. The meltdown temperature of the separator was increased to 170 °C with an acceptable reduction in the air permeability when the separator was coated with composite using the latter method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901141u [article] Enhancement of the meltdown temperature of a lithium ion battery separator via a nanocomposite coating [texte imprimé] / S. H. Yoo, Auteur ; C. K. Kim, Auteur . - 2010 . - pp. 9936–9941. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9936–9941 Mots-clés : Lithium ion battery separator Meltdown temperature Résumé : In a previous study, a lithium ion battery separator was coated with polymers synthesized from various ethylene glycol dimethacrylates to enhance its meltdown temperature. The meltdown temperature of the separator was increased to 155 °C when it was coated with polymer synthesized from diethylene glycol dimethacrylate (DEGDMA). In this study, a PE separator was coated with nanocomposites composed of DEGDMA polymer and silica nanoparticles for further enhancement of the meltdown temperature. Coatings with nanocomposites were prepared via two different methods: coating the separator by reacting a methanol solution containing DEGDMA and silica nanoparticles or coating the separator by reacting with a methanol solution containing water, DEGDMA, and tetraethylorthosilicate. The formation of nanocomposite on the separator was confirmed by FT-IR, EDS, and electron microscopy. Regardless of the coating method, an increase in the meltdown temperature with a decrease in the air permeability was observed with the nanocomposite coating. The meltdown temperature of the separator was increased to 170 °C with an acceptable reduction in the air permeability when the separator was coated with composite using the latter method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901141u

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Rheology, morphology, mechanical properties and free volume of poly(trimethylene terephthalate)/polycarbonate blends / Indose Aravind in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9942–9951 Titre : Rheology, morphology, mechanical properties and free volume of poly(trimethylene terephthalate)/polycarbonate blends Type de document : texte imprimé Auteurs : Indose Aravind, Auteur ; Kyung Hyun Ahn, Auteur ; C. Ranganathaiah, Auteur Année de publication : 2010 Article en page(s) : pp. 9942–9951 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : poly(trimethylene terephthalate)/polycarbonate blends Rheological measurements Résumé : The phase morphology, rheology, mechanical properties, and free volume of poly(trimethylene terephthalate)/polycarbonate (PTT/PC) blends have been investigated as a function of composition. The morphology indicated a two-phase structure, and the blends showed co continuous phase morphology between 30−60 wt % of poly carbonate. Due to the high viscosity of PC, PTT is more finely dispersed in the PC matrix than PC in the PTT matrix. The rheological measurements of the blends revealed that the complex viscosity increased with increase in PC content. Relatively low interfacial tension values of the blends determined using Palierne and Choi−Schowalter methods indicated that there is considerable interaction between the blend components (PTT and PC) due to the transesterification reactions. A random copolyester formed as a result of the transesterification acted as a compatibilizer in the initial stages of reactions which is the main factor for the change in miscibility. The phase morphology and the interfacial adhesion influence the mechanical properties such that addition of the PC phase decreases the tensile strength and Young’s modulus of the system. The free volume data from PALS results showed a slight positive deviation from the known linear additivity rule with increase in PC content, suggesting the blends are partially miscible. Our results show a good correlation among the phase morphology, rheology, mechanical, and free volume parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007503 [article] Rheology, morphology, mechanical properties and free volume of poly(trimethylene terephthalate)/polycarbonate blends [texte imprimé] / Indose Aravind, Auteur ; Kyung Hyun Ahn, Auteur ; C. Ranganathaiah, Auteur . - 2010 . - pp. 9942–9951. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9942–9951 Mots-clés : poly(trimethylene terephthalate)/polycarbonate blends Rheological measurements Résumé : The phase morphology, rheology, mechanical properties, and free volume of poly(trimethylene terephthalate)/polycarbonate (PTT/PC) blends have been investigated as a function of composition. The morphology indicated a two-phase structure, and the blends showed co continuous phase morphology between 30−60 wt % of poly carbonate. Due to the high viscosity of PC, PTT is more finely dispersed in the PC matrix than PC in the PTT matrix. The rheological measurements of the blends revealed that the complex viscosity increased with increase in PC content. Relatively low interfacial tension values of the blends determined using Palierne and Choi−Schowalter methods indicated that there is considerable interaction between the blend components (PTT and PC) due to the transesterification reactions. A random copolyester formed as a result of the transesterification acted as a compatibilizer in the initial stages of reactions which is the main factor for the change in miscibility. The phase morphology and the interfacial adhesion influence the mechanical properties such that addition of the PC phase decreases the tensile strength and Young’s modulus of the system. The free volume data from PALS results showed a slight positive deviation from the known linear additivity rule with increase in PC content, suggesting the blends are partially miscible. Our results show a good correlation among the phase morphology, rheology, mechanical, and free volume parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007503

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Measurements and correlation of octyltriethoxysilane solubility in supercritical CO2 and assembly of functional silane monolayers on the surface of nanometric particles / Carlos A. García-González in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9952–9960 Titre : Measurements and correlation of octyltriethoxysilane solubility in supercritical CO2 and assembly of functional silane monolayers on the surface of nanometric particles Type de document : texte imprimé Auteurs : Carlos A. García-González, Auteur ; Julio Fraile, Auteur ; Ana López-Periago, Auteur Année de publication : 2010 Article en page(s) : pp. 9952–9960 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Trialkoxysilanes Inorganic nanoparticles Nanometric fillers Supercritical carbon dioxide Résumé : Trialkoxysilanes are widely used as primers to functionalize inorganic nanoparticles and to facilitate their interaction with organic phases. In this work, the silanization of nanometric fillers (titania and maghemite) was successfully carried out using supercritical carbon dioxide as the carrier solvent for octyltrialkoxysilane. First, the solubitility behavior of octyltriethoxysilane in compressed CO2 was evaluated at different pressures and temperatures. The measured solubility data were correlated using the Chrastil equation. Next, nanometric powders of either titania or maghemite were silanized at different pressures, temperatures, and reaction times. The prepared samples were characterized by electron microscopy, N2 adsorption−desorption, and laser scattering. Finally, the operating conditions that led to optimal material performance as a function of the intended application for the coated titanium dioxide powder (UV filter in cosmetics and filler in plastics) were evaluated by means of conveniently defined objective functions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900775z [article] Measurements and correlation of octyltriethoxysilane solubility in supercritical CO2 and assembly of functional silane monolayers on the surface of nanometric particles [texte imprimé] / Carlos A. García-González, Auteur ; Julio Fraile, Auteur ; Ana López-Periago, Auteur . - 2010 . - pp. 9952–9960. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9952–9960 Mots-clés : Trialkoxysilanes Inorganic nanoparticles Nanometric fillers Supercritical carbon dioxide Résumé : Trialkoxysilanes are widely used as primers to functionalize inorganic nanoparticles and to facilitate their interaction with organic phases. In this work, the silanization of nanometric fillers (titania and maghemite) was successfully carried out using supercritical carbon dioxide as the carrier solvent for octyltrialkoxysilane. First, the solubitility behavior of octyltriethoxysilane in compressed CO2 was evaluated at different pressures and temperatures. The measured solubility data were correlated using the Chrastil equation. Next, nanometric powders of either titania or maghemite were silanized at different pressures, temperatures, and reaction times. The prepared samples were characterized by electron microscopy, N2 adsorption−desorption, and laser scattering. Finally, the operating conditions that led to optimal material performance as a function of the intended application for the coated titanium dioxide powder (UV filter in cosmetics and filler in plastics) were evaluated by means of conveniently defined objective functions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900775z

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Managing distribution in supply chain networks / Rodolfo Dondo in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9961–9978 Titre : Managing distribution in supply chain networks Type de document : texte imprimé Auteurs : Rodolfo Dondo, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur Année de publication : 2010 Article en page(s) : pp. 9961–9978 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Multiechelon multiproduct transportation networks Chemical supply chains Résumé : This paper presents a novel optimization approach to the short-term operational planning of multiechelon multiproduct transportation networks. Distribution activities commonly arising in real-world chemical supply chains involve the shipping of a number of commodities from factories to customers directly and/or via distribution centers and regional warehouses. To optimally manage such complex distribution systems, a more general vehicle routing problem in supply chain management (VRP-SCM) has been defined. The new VRP-SCM problem better resembles the logistics activities to be planned at multisite manufacturing firms by allowing multiple events at every location. In this way, two or more vehicles can visit a given location to perform pickup and/or delivery operations, and vehicle routes may include several stops at the same site, i.e., multiple tours per route. More important, the allocation of customers to suppliers and the quantities of products shipped from each source to a particular client are additional model decisions. Both the capacitated vehicle routing problem (VRP) and the pickup-and-delivery problem (PDP) can be regarded as particular instances of the new VRP-SCM. The proposed MILP mathematical formulation for the VRP-SCM problem relies on a continuous-time representation and applies the general precedence notion to model the sequencing constraints establishing the ordering of vehicle stops on every route. The approach provides a very detailed set of optimal vehicle routes and schedules to meet all product demands at minimum total transportation cost. Several examples involving up to 26 locations, four products, and six vehicles housed in four different depots have been solved to optimality in very short CPU times. En ligne : This paper presents a novel optimization approach to the short-term operational  [...] [article] Managing distribution in supply chain networks [texte imprimé] / Rodolfo Dondo, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur . - 2010 . - pp. 9961–9978. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9961–9978 Mots-clés : Multiechelon multiproduct transportation networks Chemical supply chains Résumé : This paper presents a novel optimization approach to the short-term operational planning of multiechelon multiproduct transportation networks. Distribution activities commonly arising in real-world chemical supply chains involve the shipping of a number of commodities from factories to customers directly and/or via distribution centers and regional warehouses. To optimally manage such complex distribution systems, a more general vehicle routing problem in supply chain management (VRP-SCM) has been defined. The new VRP-SCM problem better resembles the logistics activities to be planned at multisite manufacturing firms by allowing multiple events at every location. In this way, two or more vehicles can visit a given location to perform pickup and/or delivery operations, and vehicle routes may include several stops at the same site, i.e., multiple tours per route. More important, the allocation of customers to suppliers and the quantities of products shipped from each source to a particular client are additional model decisions. Both the capacitated vehicle routing problem (VRP) and the pickup-and-delivery problem (PDP) can be regarded as particular instances of the new VRP-SCM. The proposed MILP mathematical formulation for the VRP-SCM problem relies on a continuous-time representation and applies the general precedence notion to model the sequencing constraints establishing the ordering of vehicle stops on every route. The approach provides a very detailed set of optimal vehicle routes and schedules to meet all product demands at minimum total transportation cost. Several examples involving up to 26 locations, four products, and six vehicles housed in four different depots have been solved to optimality in very short CPU times. En ligne : This paper presents a novel optimization approach to the short-term operational  [...]

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Efficient numerical solver for partially structured differential and algebraic equation systems / Flavio Manenti in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9979–9984 Titre : Efficient numerical solver for partially structured differential and algebraic equation systems Type de document : texte imprimé Auteurs : Flavio Manenti, Auteur ; Ivan Dones, Auteur ; Guido Buzzi-Ferraris, Auteur Année de publication : 2010 Article en page(s) : pp. 9979–9984 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Differential and algebraic equations Sparse set Résumé : Given a sparse set of differential and algebraic equations (DAEs), it is always recommended to exploit the structure of the system’s sparsity (e.g., tridiagonal blocks matrix, band matrix, and staircase matrix, etc.), thus to use tailored numerical solvers in order to reduce the computation time. Very frequently, though, while highly structured, a couple of elements enter the description which make it difficult for the solvers to reach a solution. They are common in process control applications, where the states added to the plant description by the integral parts of the controllers introduce unstructured elements in the otherwise very structured Jacobian of the mathematical model. Such systems are characterized by a partially structured Jacobian, which inhibits the use of the solvers tailored to fit problems with fully structured matrices. In such cases, one can either use a solver with lower performance, resulting in larger computation times, or alternatively one seeks an approximation for the unstructured points. A solution to the handling of “dirty” Jacobians is presented, which is implemented in a DAE solver package available freely on the Internet. This novel DAE solver fully exploits the overall structure of the system’s sparsity, without compromising CPU computation time and precision of the results. A numerical comparison with different approaches is given by solving a DAE model representing an existing nonequilibrium distillation column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007908 [article] Efficient numerical solver for partially structured differential and algebraic equation systems [texte imprimé] / Flavio Manenti, Auteur ; Ivan Dones, Auteur ; Guido Buzzi-Ferraris, Auteur . - 2010 . - pp. 9979–9984. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9979–9984 Mots-clés : Differential and algebraic equations Sparse set Résumé : Given a sparse set of differential and algebraic equations (DAEs), it is always recommended to exploit the structure of the system’s sparsity (e.g., tridiagonal blocks matrix, band matrix, and staircase matrix, etc.), thus to use tailored numerical solvers in order to reduce the computation time. Very frequently, though, while highly structured, a couple of elements enter the description which make it difficult for the solvers to reach a solution. They are common in process control applications, where the states added to the plant description by the integral parts of the controllers introduce unstructured elements in the otherwise very structured Jacobian of the mathematical model. Such systems are characterized by a partially structured Jacobian, which inhibits the use of the solvers tailored to fit problems with fully structured matrices. In such cases, one can either use a solver with lower performance, resulting in larger computation times, or alternatively one seeks an approximation for the unstructured points. A solution to the handling of “dirty” Jacobians is presented, which is implemented in a DAE solver package available freely on the Internet. This novel DAE solver fully exploits the overall structure of the system’s sparsity, without compromising CPU computation time and precision of the results. A numerical comparison with different approaches is given by solving a DAE model representing an existing nonequilibrium distillation column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007908

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Methodology for designing and comparing robust linear versus gain-scheduled model predictive controllers / Rosendo Diaz-Mendoza in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9985–9998 Titre : Methodology for designing and comparing robust linear versus gain-scheduled model predictive controllers Type de document : texte imprimé Auteurs : Rosendo Diaz-Mendoza, Auteur ; Jianying Gao, Auteur ; Hector Budman, Auteur Année de publication : 2010 Article en page(s) : pp. 9985–9998 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gain-Scheduled Model Predictive Control Nonlinear state-affine model Stability Résumé : A methodology is proposed to design a robust Gain-Scheduled Model Predictive Control (MPC) strategy and to quantify the relative advantages of this controller versus a Linear MPC strategy. For the purpose of analysis and controller design, the process is represented by a nonlinear state-affine model identified from input−output data. This model can be split in linear and nonlinear terms where the linear part is used for controller design and the nonlinear part is accounted for as model uncertainty. Then, robust stability and robust performance tests are formulated based on linear matrix inequalities where the manipulated variables weight of the controllers is tuned to maximize performance. The uncertainty bounds used for the robustness tests are obtained in an iterative fashion by using the frequency response of the manipulated variable with respect to the feedback error. The control strategy performance is quantified by the ratio between the error norm and the disturbance norm. Finally, a case study involving a multiple-input−multiple-output bioreactor is presented. The study is able to predict for which range of operation the Gain-Scheduling MPC surpasses the performance of the Linear MPC. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900309s [article] Methodology for designing and comparing robust linear versus gain-scheduled model predictive controllers [texte imprimé] / Rosendo Diaz-Mendoza, Auteur ; Jianying Gao, Auteur ; Hector Budman, Auteur . - 2010 . - pp. 9985–9998. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9985–9998 Mots-clés : Gain-Scheduled Model Predictive Control Nonlinear state-affine model Stability Résumé : A methodology is proposed to design a robust Gain-Scheduled Model Predictive Control (MPC) strategy and to quantify the relative advantages of this controller versus a Linear MPC strategy. For the purpose of analysis and controller design, the process is represented by a nonlinear state-affine model identified from input−output data. This model can be split in linear and nonlinear terms where the linear part is used for controller design and the nonlinear part is accounted for as model uncertainty. Then, robust stability and robust performance tests are formulated based on linear matrix inequalities where the manipulated variables weight of the controllers is tuned to maximize performance. The uncertainty bounds used for the robustness tests are obtained in an iterative fashion by using the frequency response of the manipulated variable with respect to the feedback error. The control strategy performance is quantified by the ratio between the error norm and the disturbance norm. Finally, a case study involving a multiple-input−multiple-output bioreactor is presented. The study is able to predict for which range of operation the Gain-Scheduling MPC surpasses the performance of the Linear MPC. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900309s

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Integrated analysis of energy, economic, and environmental performance of biomethanol from rice straw in China / Jun Xiao in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9999–10007 Titre : Integrated analysis of energy, economic, and environmental performance of biomethanol from rice straw in China Type de document : texte imprimé Auteurs : Jun Xiao, Auteur ; Laihong Shen, Auteur ; Yanan Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 9999–10007 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Rice straw process Biomethanol China Résumé : This paper focuses on a biomethanol from the rice straw process involving the thermodynamic, economic, and environmental performance in China. Based on the simulation of methanol synthesis via biomass gasification in interconnected fluidized beds using Aspen Plus software, the method of LCA (Life Cycle Assessment) is applied to evaluate the impact of pollutant emissions in the full life cycles of biomethanol. The integrated performance of biomethanol system is analyzed combining with energy utilization, economic cost, and environmental impact. The results show that the methanol yield can reach 0.308 kg/(kg rice straw), i.e., the energy efficiency of rice straw conversion to biomethanol is approximately 42.7%. For a biomethanol plant with an annual production of 50,000 tons, the real cost of biomethanol is evaluated at 2685 RMB/t, in which the economic cost is 2347 RMB/t, and the environmental cost is 337.6 RMB/t. Because of its high investment cost, presently the economic cost of biomethanol is higher than that of coal-based methanol in China. Nevertheless biomethanol will be becoming more competitive with the shortage of fossil fuel in the future. In the whole life cycle, the main pollutant emissions come from the biomethanol production process and biomethanol end-use by automobiles, whereas the net environmental effect is negative during the rice cultivation. Global warming is the most influential factor of the different impact categories. However, 1910 kg of CO2 can be fixed for one ton of methanol by photosynthesis in the growth of rice, thus the effect of global warming is significantly reduced by biomass utilization compared with coal-based methanol. The integrated performance indicates that producing methanol from rice straw is beneficial to both the utilization of agriculture waste and in the improvement of environment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900680d [article] Integrated analysis of energy, economic, and environmental performance of biomethanol from rice straw in China [texte imprimé] / Jun Xiao, Auteur ; Laihong Shen, Auteur ; Yanan Zhang, Auteur . - 2010 . - pp. 9999–10007. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9999–10007 Mots-clés : Rice straw process Biomethanol China Résumé : This paper focuses on a biomethanol from the rice straw process involving the thermodynamic, economic, and environmental performance in China. Based on the simulation of methanol synthesis via biomass gasification in interconnected fluidized beds using Aspen Plus software, the method of LCA (Life Cycle Assessment) is applied to evaluate the impact of pollutant emissions in the full life cycles of biomethanol. The integrated performance of biomethanol system is analyzed combining with energy utilization, economic cost, and environmental impact. The results show that the methanol yield can reach 0.308 kg/(kg rice straw), i.e., the energy efficiency of rice straw conversion to biomethanol is approximately 42.7%. For a biomethanol plant with an annual production of 50,000 tons, the real cost of biomethanol is evaluated at 2685 RMB/t, in which the economic cost is 2347 RMB/t, and the environmental cost is 337.6 RMB/t. Because of its high investment cost, presently the economic cost of biomethanol is higher than that of coal-based methanol in China. Nevertheless biomethanol will be becoming more competitive with the shortage of fossil fuel in the future. In the whole life cycle, the main pollutant emissions come from the biomethanol production process and biomethanol end-use by automobiles, whereas the net environmental effect is negative during the rice cultivation. Global warming is the most influential factor of the different impact categories. However, 1910 kg of CO2 can be fixed for one ton of methanol by photosynthesis in the growth of rice, thus the effect of global warming is significantly reduced by biomass utilization compared with coal-based methanol. The integrated performance indicates that producing methanol from rice straw is beneficial to both the utilization of agriculture waste and in the improvement of environment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900680d

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Mass transfer enhancement in liquid−liquid extraction with very dilute aqueous salt solutions / Javad Saien in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10008–10014 Titre : Mass transfer enhancement in liquid−liquid extraction with very dilute aqueous salt solutions Type de document : texte imprimé Auteurs : Javad Saien, Auteur ; Fatemeh Ashrafi, Auteur Année de publication : 2010 Article en page(s) : pp. 10008–10014 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Liquid−  liquid extraction chemical system Mass transfer Résumé : The effect of very low salt addition in the recommended liquid−liquid extraction chemical system of toluene−acetone−water was investigated with circulating single drops and in both of the mass transfer directions. By adding sodium chloride, potassium chloride, and potassium iodide, within the concentration range of 10−6−10−4 mol/L, into the continuous phase and under constant pH, the mass transfer rate finds enhancements to about 425%. A high trend of variation was observed for the salt concentrations until only about 10−5 mol/L. This phenomenon can be attributed to the hydration of ions which favors acetone to be transferred easier in the aqueous phase. Small drops are usually more benefited, and the rate of mass transfer is greater for the dispersed to continuous phase direction under similar conditions due to a higher dominant extraction fraction, whereas the drop size decreases in this direction. The effectiveness of salts in this matter appeared to be in the order of NaCl > KCl > KI. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900542w [article] Mass transfer enhancement in liquid−liquid extraction with very dilute aqueous salt solutions [texte imprimé] / Javad Saien, Auteur ; Fatemeh Ashrafi, Auteur . - 2010 . - pp. 10008–10014. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10008–10014 Mots-clés : Liquid−  liquid extraction chemical system Mass transfer Résumé : The effect of very low salt addition in the recommended liquid−liquid extraction chemical system of toluene−acetone−water was investigated with circulating single drops and in both of the mass transfer directions. By adding sodium chloride, potassium chloride, and potassium iodide, within the concentration range of 10−6−10−4 mol/L, into the continuous phase and under constant pH, the mass transfer rate finds enhancements to about 425%. A high trend of variation was observed for the salt concentrations until only about 10−5 mol/L. This phenomenon can be attributed to the hydration of ions which favors acetone to be transferred easier in the aqueous phase. Small drops are usually more benefited, and the rate of mass transfer is greater for the dispersed to continuous phase direction under similar conditions due to a higher dominant extraction fraction, whereas the drop size decreases in this direction. The effectiveness of salts in this matter appeared to be in the order of NaCl > KCl > KI. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900542w

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Adsorption and diffusion of carbon dioxide on metal−organic framework (MOF-5) / Zhenxia Zhao in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10015–10020 Titre : Adsorption and diffusion of carbon dioxide on metal−organic framework (MOF-5) Type de document : texte imprimé Auteurs : Zhenxia Zhao, Auteur ; Zhong Li, Auteur ; Y. S. Lin, Auteur Année de publication : 2010 Article en page(s) : pp. 10015–10020 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Microporous metal−  organic framework Adsorption equilibrium Diffusion Résumé : Adsorption equilibrium and diffusion of CO2 on microporous metal−organic frameworks (MOF-5, or IRMOF-1) crystals were experimentally studied by the gravimetric method in the pressure range up to 1 atm. The MOF-5 crystal cubes of about 40−60 μm in sizes were synthesized by the solvothermal method. Freundlich adsorption isotherm equation can fit well CO2 adsorption isotherms on MOF-5, with isosteric heat of adsorption of about 34 kJ/mol. Diffusion coefficient of CO2 in the MOF-5 is in the range of 8.1−11.5 × 10−9 cm2/s in 295−331K with activation energy of 7.61 kJ/mol. MOF-5 offers attractive adsorption properties as an adsorbent for separation of CO2 from flue gas. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900665f [article] Adsorption and diffusion of carbon dioxide on metal−organic framework (MOF-5) [texte imprimé] / Zhenxia Zhao, Auteur ; Zhong Li, Auteur ; Y. S. Lin, Auteur . - 2010 . - pp. 10015–10020. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10015–10020 Mots-clés : Microporous metal−  organic framework Adsorption equilibrium Diffusion Résumé : Adsorption equilibrium and diffusion of CO2 on microporous metal−organic frameworks (MOF-5, or IRMOF-1) crystals were experimentally studied by the gravimetric method in the pressure range up to 1 atm. The MOF-5 crystal cubes of about 40−60 μm in sizes were synthesized by the solvothermal method. Freundlich adsorption isotherm equation can fit well CO2 adsorption isotherms on MOF-5, with isosteric heat of adsorption of about 34 kJ/mol. Diffusion coefficient of CO2 in the MOF-5 is in the range of 8.1−11.5 × 10−9 cm2/s in 295−331K with activation energy of 7.61 kJ/mol. MOF-5 offers attractive adsorption properties as an adsorbent for separation of CO2 from flue gas. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900665f

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Correlation of crystal lattice expansion and membrane properties for MFI zeolites / Stephanie G. Sorenson in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10021–10024 Titre : Correlation of crystal lattice expansion and membrane properties for MFI zeolites Type de document : texte imprimé Auteurs : Stephanie G. Sorenson, Auteur ; Joseph R. Smyth, Auteur ; Richard D. Noble, Auteur Année de publication : 2010 Article en page(s) : pp. 10021–10024 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : MFI zeolites Correlation X-ray diffraction measurements Résumé : X-ray diffraction measurements show that saturation loadings of C5−C13 n-alkanes at room temperature increased the unit cell size of silicalite-1 crystals, and the percent volume expansion correlated linearly with the number of carbon atoms per unit cell. Adsorption of tridecane expanded the zeolite the most (1.53 vol %), but all n-alkanes and alcohols studied expanded MFI crystals. Pervaporation fluxes of isooctane through defects in B-ZSM-5 membranes at 313 K decreased 2 orders of magnitude when n-alkanes were added to the feed, and the percentage decrease correlated with crystal expansion; n-alkanes that expanded crystals more caused the flux through defects to decrease more. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901073g [article] Correlation of crystal lattice expansion and membrane properties for MFI zeolites [texte imprimé] / Stephanie G. Sorenson, Auteur ; Joseph R. Smyth, Auteur ; Richard D. Noble, Auteur . - 2010 . - pp. 10021–10024. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10021–10024 Mots-clés : MFI zeolites Correlation X-ray diffraction measurements Résumé : X-ray diffraction measurements show that saturation loadings of C5−C13 n-alkanes at room temperature increased the unit cell size of silicalite-1 crystals, and the percent volume expansion correlated linearly with the number of carbon atoms per unit cell. Adsorption of tridecane expanded the zeolite the most (1.53 vol %), but all n-alkanes and alcohols studied expanded MFI crystals. Pervaporation fluxes of isooctane through defects in B-ZSM-5 membranes at 313 K decreased 2 orders of magnitude when n-alkanes were added to the feed, and the percentage decrease correlated with crystal expansion; n-alkanes that expanded crystals more caused the flux through defects to decrease more. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901073g

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On the fluid mechanics of spiral-wound membrane modules / M. Kostoglou in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10025–10036 Titre : On the fluid mechanics of spiral-wound membrane modules Type de document : texte imprimé Auteurs : M. Kostoglou, Auteur ; Anastasios J. Karabelas, Auteur Année de publication : 2010 Article en page(s) : pp. 10025–10036 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Spiral-wound membrane modules Fluid mechanics Résumé : Spiral-wound membrane (SWM) modules are comprised of several large-size membrane sheets with a net-type spacer at the retentate flow channel and a porous cloth/filler at the low-pressure permeate side; thus, two strongly interacting flow fields exist with spatially variable properties. Mathematical models of the SWM operation, based on an accurate description of transport phenomena taking place in those narrow flow passages, are necessary tools for optimizing both module design parameters and the entire membrane-based plant. Such integrated SWM models are not available at present. In this problem, the coexistence of several flow length scales, from the pores of the permeate side filler to the macroscopic dimensions of the module, renders the modeling task quite complicated. Typical modeling efforts vary between the extremes of detailed description of transport phenomena at small scale to macroscopic phenomenological-type simulation of the entire separation process in a module. The scope of this work is to describe the hydrodynamics of spiral-wound membranes, starting from first principles, to suggest and analyze some realistic approximations and their origin and to present an integrated model where linking phenomena at different length scales is an essential feature. This effort has resulted in an efficient numerical algorithm, allowing predictions of the spatial distribution of pressure, permeation, and cross-flow velocities throughout the membrane leaves. In this work, all possible analytical solutions have been derived which facilitate the development of the simulation algorithm. Typical examples of predicted flow and pressure distributions are presented. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901129j [article] On the fluid mechanics of spiral-wound membrane modules [texte imprimé] / M. Kostoglou, Auteur ; Anastasios J. Karabelas, Auteur . - 2010 . - pp. 10025–10036. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10025–10036 Mots-clés : Spiral-wound membrane modules Fluid mechanics Résumé : Spiral-wound membrane (SWM) modules are comprised of several large-size membrane sheets with a net-type spacer at the retentate flow channel and a porous cloth/filler at the low-pressure permeate side; thus, two strongly interacting flow fields exist with spatially variable properties. Mathematical models of the SWM operation, based on an accurate description of transport phenomena taking place in those narrow flow passages, are necessary tools for optimizing both module design parameters and the entire membrane-based plant. Such integrated SWM models are not available at present. In this problem, the coexistence of several flow length scales, from the pores of the permeate side filler to the macroscopic dimensions of the module, renders the modeling task quite complicated. Typical modeling efforts vary between the extremes of detailed description of transport phenomena at small scale to macroscopic phenomenological-type simulation of the entire separation process in a module. The scope of this work is to describe the hydrodynamics of spiral-wound membranes, starting from first principles, to suggest and analyze some realistic approximations and their origin and to present an integrated model where linking phenomena at different length scales is an essential feature. This effort has resulted in an efficient numerical algorithm, allowing predictions of the spatial distribution of pressure, permeation, and cross-flow velocities throughout the membrane leaves. In this work, all possible analytical solutions have been derived which facilitate the development of the simulation algorithm. Typical examples of predicted flow and pressure distributions are presented. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901129j

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Simultaneous removal of urea, ammonia, and carbon dioxide from industrial wastewater using a thermal hydrolyzer−separator loop / M. R. Rahimpour in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10037–10046 Titre : Simultaneous removal of urea, ammonia, and carbon dioxide from industrial wastewater using a thermal hydrolyzer−separator loop Type de document : texte imprimé Auteurs : M. R. Rahimpour, Auteur ; H. R. Mottaghi, Auteur Année de publication : 2010 Article en page(s) : pp. 10037–10046 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Industrial wastewater Hydrolyzer−  separator loop Résumé : In this work, simultaneous removal of urea, ammonia, and carbon dioxide from industrial wastewater was studied via modeling and simulation of a hydrolyzer−separator loop. The extended electrolytic UNIQUAC equation has been used to describe the nonideality of the liquid phase and the perturbed-hard-sphere (PHS) equation of state has been applied to predict the vapor fugacity coefficients. This work also uses a multistage well-mixed model for the liquid and vapor flows with a nonideal rate-based model for urea thermal hydrolyzer. Our study incorporates the reaction rate of urea hydrolysis and takes into account the effects of solution nonideality and backmixing on the reactor performance. The rates of urea reaction are written in terms of activity of reactants. The model provides temperature and flow rate distributions of different components along the height of the hydrolysis reactor and the desorbers. The simulation results have been found to be in good agreement with the plant data indicating the validity of the model. The impact of different parameters on the performance of the wastewater treatment loop has been examined. The results of this work showed that an increase in the inlet temperature of the wastewater and steam flow rate and also decrease the reflux ratio would improve the urea and ammonia removal efficiency. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900751g [article] Simultaneous removal of urea, ammonia, and carbon dioxide from industrial wastewater using a thermal hydrolyzer−separator loop [texte imprimé] / M. R. Rahimpour, Auteur ; H. R. Mottaghi, Auteur . - 2010 . - pp. 10037–10046. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10037–10046 Mots-clés : Industrial wastewater Hydrolyzer−  separator loop Résumé : In this work, simultaneous removal of urea, ammonia, and carbon dioxide from industrial wastewater was studied via modeling and simulation of a hydrolyzer−separator loop. The extended electrolytic UNIQUAC equation has been used to describe the nonideality of the liquid phase and the perturbed-hard-sphere (PHS) equation of state has been applied to predict the vapor fugacity coefficients. This work also uses a multistage well-mixed model for the liquid and vapor flows with a nonideal rate-based model for urea thermal hydrolyzer. Our study incorporates the reaction rate of urea hydrolysis and takes into account the effects of solution nonideality and backmixing on the reactor performance. The rates of urea reaction are written in terms of activity of reactants. The model provides temperature and flow rate distributions of different components along the height of the hydrolysis reactor and the desorbers. The simulation results have been found to be in good agreement with the plant data indicating the validity of the model. The impact of different parameters on the performance of the wastewater treatment loop has been examined. The results of this work showed that an increase in the inlet temperature of the wastewater and steam flow rate and also decrease the reflux ratio would improve the urea and ammonia removal efficiency. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900751g

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Residence time distribution of liquid and solid phases in a novel staged crystallizer / Zai Qun Yu in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10047–10054 Titre : Residence time distribution of liquid and solid phases in a novel staged crystallizer Type de document : texte imprimé Auteurs : Zai Qun Yu, Auteur ; Pui Shan Chow, Auteur ; Reginald B. H. Tan, Auteur Année de publication : 2010 Article en page(s) : pp. 10047–10054 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Staged crystallizer Résumé : A novel vertically staged continuous crystallizer is proposed in this work. It consists of a series of compartments stacked one above another with partition plates in between. A stirrer shaft with multiple impellers provides agitation in each compartment. Solution to be crystallized enters the crystallizer from the top and flows downward through all stages. Crystal product and mother liquor are collected from the bottom. Openings in partition plates with accessories attached serve as passages for slurry flow, allowing for control over interstage mixing of liquid phase and residence time distribution (RTD) of crystals. The hydrodynamics of such a crystallizer is investigated in a two-stage experimental setup. Water, PVC particles, and glass beads are used to investigate the influences of design and operating factors on interstage mixing of liquid phase and RTDs of both liquid and solid phases. Results show that interstage mixing of liquid phase can be repressed successfully to ensure the establishment of supersaturation gradient across stages. RTD of solid phase can be manipulated by adjusting the feeding rate of liquid phase and opening size in the partition plate. Average residence time of solids deceases with increasing particle size, leading to classification of particles. A model is proposed for the RTD of solid phase which agrees with experimental data very well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006722 [article] Residence time distribution of liquid and solid phases in a novel staged crystallizer [texte imprimé] / Zai Qun Yu, Auteur ; Pui Shan Chow, Auteur ; Reginald B. H. Tan, Auteur . - 2010 . - pp. 10047–10054. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10047–10054 Mots-clés : Staged crystallizer Résumé : A novel vertically staged continuous crystallizer is proposed in this work. It consists of a series of compartments stacked one above another with partition plates in between. A stirrer shaft with multiple impellers provides agitation in each compartment. Solution to be crystallized enters the crystallizer from the top and flows downward through all stages. Crystal product and mother liquor are collected from the bottom. Openings in partition plates with accessories attached serve as passages for slurry flow, allowing for control over interstage mixing of liquid phase and residence time distribution (RTD) of crystals. The hydrodynamics of such a crystallizer is investigated in a two-stage experimental setup. Water, PVC particles, and glass beads are used to investigate the influences of design and operating factors on interstage mixing of liquid phase and RTDs of both liquid and solid phases. Results show that interstage mixing of liquid phase can be repressed successfully to ensure the establishment of supersaturation gradient across stages. RTD of solid phase can be manipulated by adjusting the feeding rate of liquid phase and opening size in the partition plate. Average residence time of solids deceases with increasing particle size, leading to classification of particles. A model is proposed for the RTD of solid phase which agrees with experimental data very well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006722

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Experimental study of the effect of particle density on mixing behavior in a spout-fluid bed / Baosheng Jin in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10055–10064 Titre : Experimental study of the effect of particle density on mixing behavior in a spout-fluid bed Type de document : texte imprimé Auteurs : Baosheng Jin, Auteur ; Yong Zhang, Auteur ; Wenqi Zhong, Auteur Année de publication : 2010 Article en page(s) : pp. 10055–10064 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Mixing behavior Spout-fluid bed Experimental study Résumé : The particle mixing behavior has been investigated experimentally in a spout-fluid bed. The bed material used is polypropylene particles, and the tracer employed is chosen from silica gel, mung beans, and glass beads. During all experiments, the completely segregated arrangement of particles is adopted as the initial packing condition. The gas velocity varies to cover internal jet, minimum spouting, and fully developed spouting conditions, in order to establish a full mixing map about the effect of particle density. The mixing behavior is analyzed in terms of flow patterns, concentration profile, and mixing index. The results show that the degree and rate of mixing are significantly affected by the particle density, and heavier particles achieve a higher mixing rate but a poorer mixing quality. The mixing map reveals that to reach the same mixing index, the spouting gas velocity needs to increase with the increase of particle density. Besides, provided that the jet gas velocity does not exceed the minimum spouting gas velocity, a segregation phenomenon can always be observed by simply adjusting the ratio of the fluidizing to spouting gas velocity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900689r [article] Experimental study of the effect of particle density on mixing behavior in a spout-fluid bed [texte imprimé] / Baosheng Jin, Auteur ; Yong Zhang, Auteur ; Wenqi Zhong, Auteur . - 2010 . - pp. 10055–10064. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10055–10064 Mots-clés : Mixing behavior Spout-fluid bed Experimental study Résumé : The particle mixing behavior has been investigated experimentally in a spout-fluid bed. The bed material used is polypropylene particles, and the tracer employed is chosen from silica gel, mung beans, and glass beads. During all experiments, the completely segregated arrangement of particles is adopted as the initial packing condition. The gas velocity varies to cover internal jet, minimum spouting, and fully developed spouting conditions, in order to establish a full mixing map about the effect of particle density. The mixing behavior is analyzed in terms of flow patterns, concentration profile, and mixing index. The results show that the degree and rate of mixing are significantly affected by the particle density, and heavier particles achieve a higher mixing rate but a poorer mixing quality. The mixing map reveals that to reach the same mixing index, the spouting gas velocity needs to increase with the increase of particle density. Besides, provided that the jet gas velocity does not exceed the minimum spouting gas velocity, a segregation phenomenon can always be observed by simply adjusting the ratio of the fluidizing to spouting gas velocity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900689r

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Thermophysical properties of binary and ternary mixtures containing lactams and methanol / María J. Dávila in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10065–10076 Titre : Thermophysical properties of binary and ternary mixtures containing lactams and methanol Type de document : texte imprimé Auteurs : María J. Dávila, Auteur ; Santiago Aparicio, Auteur ; Rafael Alcalde, Auteur Année de publication : 2010 Article en page(s) : pp. 10065–10076 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Binary mixtures Ternary Lactams Methanol Résumé : Thermophysical properties of 2-pyrrolidone (PYR), N-methyl-2-pyrrolidone (NMP), and N-cyclohexyl-2-pyrrolidone (CHP) binary and ternary liquid mixtures with methanol are reported at 298.15 K and 0.1 MPa over the full composition range. Excess and mixing properties derived from the experimental ones were correlated using Redlich−Kister (RK) equation, for binary mixtures, and Cibulka (C) equation, for ternary ones. Density Functional Theory (DFT) was also used to analyze structural and energetic features of cyclic lactams in gas phase and methanol solution. Results show the formation of H-bonding and dipolar interactions between cyclic amides and methanol, although these are weakened when a third component is added to the binary mixture, thus decreasing remarkably the values of ternary properties in comparison with binary ones and leading to the weakening of the binary blends’ intermolecular interactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900822e [article] Thermophysical properties of binary and ternary mixtures containing lactams and methanol [texte imprimé] / María J. Dávila, Auteur ; Santiago Aparicio, Auteur ; Rafael Alcalde, Auteur . - 2010 . - pp. 10065–10076. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10065–10076 Mots-clés : Binary mixtures Ternary Lactams Methanol Résumé : Thermophysical properties of 2-pyrrolidone (PYR), N-methyl-2-pyrrolidone (NMP), and N-cyclohexyl-2-pyrrolidone (CHP) binary and ternary liquid mixtures with methanol are reported at 298.15 K and 0.1 MPa over the full composition range. Excess and mixing properties derived from the experimental ones were correlated using Redlich−Kister (RK) equation, for binary mixtures, and Cibulka (C) equation, for ternary ones. Density Functional Theory (DFT) was also used to analyze structural and energetic features of cyclic lactams in gas phase and methanol solution. Results show the formation of H-bonding and dipolar interactions between cyclic amides and methanol, although these are weakened when a third component is added to the binary mixture, thus decreasing remarkably the values of ternary properties in comparison with binary ones and leading to the weakening of the binary blends’ intermolecular interactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900822e

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Validation of ultrafilter performance model based on systematic simulant evaluation / R. L. Russell in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10077–10086 Titre : Validation of ultrafilter performance model based on systematic simulant evaluation Type de document : texte imprimé Auteurs : R. L. Russell, Auteur ; J. M. Billing, Auteur ; H. D. Smith, Auteur Année de publication : 2010 Article en page(s) : pp. 10077–10086 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ultrafilter performance model Simulant evaluation Résumé : Because of limited availability of test data with actual Hanford tank-waste samples, a method was developed to estimate expected filtration performance based on physical characterization data for the Hanford Tank Waste Treatment and Immobilization Plant. This method relies upon the similarity between the gel concentration measured during crossflow filtration and the slurry concentration measured after a sample is centrifuged. Testing was performed to determine the centrifuged-solids concentration, and then a subset of simulants was tested to determine the gel concentration during crossflow filtration. These two approaches produced identical results, indicating the centrifuged-solids concentration can be used to represent the gel concentration for filtration. This substitution will allow the expected filtration performance to be characterized at a significantly reduced cost. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901042w [article] Validation of ultrafilter performance model based on systematic simulant evaluation [texte imprimé] / R. L. Russell, Auteur ; J. M. Billing, Auteur ; H. D. Smith, Auteur . - 2010 . - pp. 10077–10086. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10077–10086 Mots-clés : Ultrafilter performance model Simulant evaluation Résumé : Because of limited availability of test data with actual Hanford tank-waste samples, a method was developed to estimate expected filtration performance based on physical characterization data for the Hanford Tank Waste Treatment and Immobilization Plant. This method relies upon the similarity between the gel concentration measured during crossflow filtration and the slurry concentration measured after a sample is centrifuged. Testing was performed to determine the centrifuged-solids concentration, and then a subset of simulants was tested to determine the gel concentration during crossflow filtration. These two approaches produced identical results, indicating the centrifuged-solids concentration can be used to represent the gel concentration for filtration. This substitution will allow the expected filtration performance to be characterized at a significantly reduced cost. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901042w

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Biomass-derived platform chemicals: thermodynamic studies on the conversion of 5-hydroxymethylfurfural into bulk intermediates / Sergey P. Verevkin in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10087–10093 Titre : Biomass-derived platform chemicals: thermodynamic studies on the conversion of 5-hydroxymethylfurfural into bulk intermediates Type de document : texte imprimé Auteurs : Sergey P. Verevkin, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Elena N. Stepurko, Auteur Année de publication : 2010 Article en page(s) : pp. 10087–10093 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : 5-hydroxymethylfurfural Bulk intermediates Résumé : This work was undertaken to obtain new thermochemical data for 5-hydroxymethylfurfural (HMF) and parent compounds. The standard molar enthalpy of formation in the gaseous state of HMF was obtained from combustion calorimetry, differential scanning calorimetry (DSC), and measurements of the temperature dependence of the vapor pressure by the transpiration method. To verify the experimental data, ab initio calculations of all compounds were performed. Enthalpies of formation derived from the G3MP2 method are in an excellent agreement with the experimental results. A weak hydrogen bond in HMF was revealed using ab initio methods. Thermodynamic analysis of the transformation of HMF to the bulk intermediates according to hydrogenation and oxidation pathways has revealed a very high feasibility of these reactions, with equilibrium constants that are completely shifted to the desired reaction products even at 298 K. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901012g [article] Biomass-derived platform chemicals: thermodynamic studies on the conversion of 5-hydroxymethylfurfural into bulk intermediates [texte imprimé] / Sergey P. Verevkin, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Elena N. Stepurko, Auteur . - 2010 . - pp. 10087–10093. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10087–10093 Mots-clés : 5-hydroxymethylfurfural Bulk intermediates Résumé : This work was undertaken to obtain new thermochemical data for 5-hydroxymethylfurfural (HMF) and parent compounds. The standard molar enthalpy of formation in the gaseous state of HMF was obtained from combustion calorimetry, differential scanning calorimetry (DSC), and measurements of the temperature dependence of the vapor pressure by the transpiration method. To verify the experimental data, ab initio calculations of all compounds were performed. Enthalpies of formation derived from the G3MP2 method are in an excellent agreement with the experimental results. A weak hydrogen bond in HMF was revealed using ab initio methods. Thermodynamic analysis of the transformation of HMF to the bulk intermediates according to hydrogenation and oxidation pathways has revealed a very high feasibility of these reactions, with equilibrium constants that are completely shifted to the desired reaction products even at 298 K. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901012g

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Modeling of multiphase flow and heat transfer in radiant syngas cooler of an entrained-flow coal gasification / Guangsuo Yu in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10094–10103 Titre : Modeling of multiphase flow and heat transfer in radiant syngas cooler of an entrained-flow coal gasification Type de document : texte imprimé Auteurs : Guangsuo Yu, Auteur ; Jianjun Ni, Auteur ; Qinfeng Liang, Auteur Année de publication : 2010 Article en page(s) : pp. 10094–10103 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : A comprehensive model has been developed to analyze the multiphase flow and heat transfer in the radiant syngas cooler (RSC) of an industrial-scale entrained-flow coal gasification. The three-dimensional multiphase flow field and temperature field were reconstructed. The realizable k−ϵ turbulence model is applied to calculate the gas flow field, while the discrete random walk model is applied to trace the particles, and the interaction between the gas and the particle is considered using a two-way coupling model. The radiative properties of syngas mixture are calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number is used to account for convection heat transfer between the gas phase and the particles. The discrete ordinate model is applied to model the radiative heat transfer, and the effect of ash/slag particles on radiative heat transfer is considered. The model was successfully validated by comparison with the industrial plant measurement data, which demonstrated the ability of the model to optimize the design. The results show that a torch shape inlet jet was formed in the RSC, and its length increased with the diameter of the central channel. The recirculation zones appeared around the inlet jet, top, and bottom of the RSC. The overall temperature decreased with the heat-transfer surface area of the fins. The concentration distribution, velocity distribution, residence time distribution, and temperature distribution of particles with different diameters have been discussed. Finally, the slag/ash particles size distribution and temperature profile at the bottom of the RSC have been presented. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901203d [article] Modeling of multiphase flow and heat transfer in radiant syngas cooler of an entrained-flow coal gasification [texte imprimé] / Guangsuo Yu, Auteur ; Jianjun Ni, Auteur ; Qinfeng Liang, Auteur . - 2010 . - pp. 10094–10103. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10094–10103 Résumé : A comprehensive model has been developed to analyze the multiphase flow and heat transfer in the radiant syngas cooler (RSC) of an industrial-scale entrained-flow coal gasification. The three-dimensional multiphase flow field and temperature field were reconstructed. The realizable k−ϵ turbulence model is applied to calculate the gas flow field, while the discrete random walk model is applied to trace the particles, and the interaction between the gas and the particle is considered using a two-way coupling model. The radiative properties of syngas mixture are calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number is used to account for convection heat transfer between the gas phase and the particles. The discrete ordinate model is applied to model the radiative heat transfer, and the effect of ash/slag particles on radiative heat transfer is considered. The model was successfully validated by comparison with the industrial plant measurement data, which demonstrated the ability of the model to optimize the design. The results show that a torch shape inlet jet was formed in the RSC, and its length increased with the diameter of the central channel. The recirculation zones appeared around the inlet jet, top, and bottom of the RSC. The overall temperature decreased with the heat-transfer surface area of the fins. The concentration distribution, velocity distribution, residence time distribution, and temperature distribution of particles with different diameters have been discussed. Finally, the slag/ash particles size distribution and temperature profile at the bottom of the RSC have been presented. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901203d

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Preparation of silver nanoparticles using a spinning disk reactor in a continuous mode / Clifford Y. Tai in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10104–10109 Titre : Preparation of silver nanoparticles using a spinning disk reactor in a continuous mode Type de document : texte imprimé Auteurs : Clifford Y. Tai, Auteur ; Yao-Hsuan Wang, Auteur ; Chia-Te Tai, Auteur Année de publication : 2010 Article en page(s) : pp. 10104–10109 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Spinning disk reactor Silver nanoparticles Hydroxypropylmethyl cellulose poly(vinylpyrrolidone) Résumé : A spinning disk reactor (SDR) operated in a continuous mode was adopted for producing silver nanoparticles, aiming at an increase in the production rate. Two protecting agents, i.e., poly(vinylpyrrolidone) (PVP) and hydroxypropylmethyl cellulose (HPMC), were tested, which have been proven to be effective in our previous work of recycle operation. Using PVP as protecting agent, the effects of the operating variables, including the rotation speed, the feeding rate, the dosage of protecting agent, and reactant concentration, on the particle size and yield of the silver product were investigated. The experiment was further conducted using HPMC as protecting agent to compare the experimental results between the two protecting agents. The use of PVP gave smaller silver nanoparticles; however, a higher yield was obtained by using HPMC. Although the yield of continuous operation was lower than that of recycle operation, the production rate was much higher for either protecting agent, providing a great potential for commercialization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005645 [article] Preparation of silver nanoparticles using a spinning disk reactor in a continuous mode [texte imprimé] / Clifford Y. Tai, Auteur ; Yao-Hsuan Wang, Auteur ; Chia-Te Tai, Auteur . - 2010 . - pp. 10104–10109. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10104–10109 Mots-clés : Spinning disk reactor Silver nanoparticles Hydroxypropylmethyl cellulose poly(vinylpyrrolidone) Résumé : A spinning disk reactor (SDR) operated in a continuous mode was adopted for producing silver nanoparticles, aiming at an increase in the production rate. Two protecting agents, i.e., poly(vinylpyrrolidone) (PVP) and hydroxypropylmethyl cellulose (HPMC), were tested, which have been proven to be effective in our previous work of recycle operation. Using PVP as protecting agent, the effects of the operating variables, including the rotation speed, the feeding rate, the dosage of protecting agent, and reactant concentration, on the particle size and yield of the silver product were investigated. The experiment was further conducted using HPMC as protecting agent to compare the experimental results between the two protecting agents. The use of PVP gave smaller silver nanoparticles; however, a higher yield was obtained by using HPMC. Although the yield of continuous operation was lower than that of recycle operation, the production rate was much higher for either protecting agent, providing a great potential for commercialization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005645

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Thermophysical properties of dry and humid air by molecular simulation including dew point calculations with the mollier ensemble / Bernhard Eckl in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10110–10119 Titre : Thermophysical properties of dry and humid air by molecular simulation including dew point calculations with the mollier ensemble Type de document : texte imprimé Auteurs : Bernhard Eckl, Auteur ; Thorsten Burkhardt, Auteur ; Jadran Vrabec, Auteur Année de publication : 2010 Article en page(s) : pp. 10110–10119 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Mollier ensemble Humid air systems Thermophysical properties Résumé : A pseudoensemble, the Mollier ensemble, is proposed for the dew point calculation of humid air systems. This approach combines features of the isobaric−isothermal (NpT) ensemble and the grand-canonical (μVT) ensemble. The molecular model for dry air is taken from previous work and compared to experimental data as well as to two recommended reference quality equations of state regarding vapor−liquid equilibria, thermal, and caloric properties. An excellent agreement is found for temperatures up to 1000 °C and pressures up to 200 MPa. For water, two different molecular models are considered, the popular TIP4P model from the literature and an optimized version that better describes the vapor pressure. Both water models are used in combination with the molecular dry air model to predict the compressed gas density as well as the dew point of humid air at 60 and 80 °C for elevated pressures up to 25 MPa. The results are in very good agreement with experimental data from the literature. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005707 [article] Thermophysical properties of dry and humid air by molecular simulation including dew point calculations with the mollier ensemble [texte imprimé] / Bernhard Eckl, Auteur ; Thorsten Burkhardt, Auteur ; Jadran Vrabec, Auteur . - 2010 . - pp. 10110–10119. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10110–10119 Mots-clés : Mollier ensemble Humid air systems Thermophysical properties Résumé : A pseudoensemble, the Mollier ensemble, is proposed for the dew point calculation of humid air systems. This approach combines features of the isobaric−isothermal (NpT) ensemble and the grand-canonical (μVT) ensemble. The molecular model for dry air is taken from previous work and compared to experimental data as well as to two recommended reference quality equations of state regarding vapor−liquid equilibria, thermal, and caloric properties. An excellent agreement is found for temperatures up to 1000 °C and pressures up to 200 MPa. For water, two different molecular models are considered, the popular TIP4P model from the literature and an optimized version that better describes the vapor pressure. Both water models are used in combination with the molecular dry air model to predict the compressed gas density as well as the dew point of humid air at 60 and 80 °C for elevated pressures up to 25 MPa. The results are in very good agreement with experimental data from the literature. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005707

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Re-investigation and data assessment of the isomerization and 2,2′-cyclization of stilbenes and azobenzenes / Heiko K. Cammenga in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10120–10128 Titre : Re-investigation and data assessment of the isomerization and 2,2′-cyclization of stilbenes and azobenzenes Type de document : texte imprimé Auteurs : Heiko K. Cammenga, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Sergey P. Verevkin, Auteur Année de publication : 2010 Article en page(s) : pp. 10120–10128 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Azobenzenes StilbenesCis/trans-isomerization Résumé : The energetics and kinetics of the thermal and photochemical cis/trans-isomerization of azobenzenes and stilbenes are of fundamental interest to physical organic chemistry, because they may serve as “reference reactions” for the various theoretical and computational methods. The same applies to the 2,2′-cyclization of these compounds to benzo(c)cinnolines and phenanthrenes. Although many investigations have been devoted to this topic, a wide variety of energetic data for these fundamental processes can be found in the literature. This paper presents both a compilation and assessment of all data hitherto published and a consistent data redetermination for these fundamental processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900800q [article] Re-investigation and data assessment of the isomerization and 2,2′-cyclization of stilbenes and azobenzenes [texte imprimé] / Heiko K. Cammenga, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Sergey P. Verevkin, Auteur . - 2010 . - pp. 10120–10128. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10120–10128 Mots-clés : Azobenzenes StilbenesCis/trans-isomerization Résumé : The energetics and kinetics of the thermal and photochemical cis/trans-isomerization of azobenzenes and stilbenes are of fundamental interest to physical organic chemistry, because they may serve as “reference reactions” for the various theoretical and computational methods. The same applies to the 2,2′-cyclization of these compounds to benzo(c)cinnolines and phenanthrenes. Although many investigations have been devoted to this topic, a wide variety of energetic data for these fundamental processes can be found in the literature. This paper presents both a compilation and assessment of all data hitherto published and a consistent data redetermination for these fundamental processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900800q

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Prediction of density and viscosity of bitumen using the Peng−Robinson equation of state / Herbert Loria in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10129–10135 Titre : Prediction of density and viscosity of bitumen using the Peng−Robinson equation of state Type de document : texte imprimé Auteurs : Herbert Loria, Auteur ; Pedro Pereira-Almao, Auteur ; Marco Satyro, Auteur Année de publication : 2010 Article en page(s) : pp. 10129–10135 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Bitumen Thermodynamic models Peng−  Robinson equation Résumé : Density and viscosity are important quantities required in engineering design for production, fluid transportation, and processing. However, there is no satisfactory theory for the calculation of these properties for bitumen. The principal objective of this paper is to obtain thermodynamic models to predict the density and viscosity of bitumen on the basis of the translated version of the Peng−Robinson equation of state. In the density calculation, a consistent correction to improve the liquid-phase volume estimation was applied. The density model evidenced a small percent average absolute error regarding experimental data (less than 1%). The model for viscosity was based on a modification of the Enskog’s equation. This modification allowed the prediction of bitumen viscosity using an equation of state along with a substance- and temperature-dependent parameter; this approach showed good accuracy with respect to experimental data. An important advantage of these models is the possibility of estimating viscosities at different pressures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901031n [article] Prediction of density and viscosity of bitumen using the Peng−Robinson equation of state [texte imprimé] / Herbert Loria, Auteur ; Pedro Pereira-Almao, Auteur ; Marco Satyro, Auteur . - 2010 . - pp. 10129–10135. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10129–10135 Mots-clés : Bitumen Thermodynamic models Peng−  Robinson equation Résumé : Density and viscosity are important quantities required in engineering design for production, fluid transportation, and processing. However, there is no satisfactory theory for the calculation of these properties for bitumen. The principal objective of this paper is to obtain thermodynamic models to predict the density and viscosity of bitumen on the basis of the translated version of the Peng−Robinson equation of state. In the density calculation, a consistent correction to improve the liquid-phase volume estimation was applied. The density model evidenced a small percent average absolute error regarding experimental data (less than 1%). The model for viscosity was based on a modification of the Enskog’s equation. This modification allowed the prediction of bitumen viscosity using an equation of state along with a substance- and temperature-dependent parameter; this approach showed good accuracy with respect to experimental data. An important advantage of these models is the possibility of estimating viscosities at different pressures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901031n

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Determination of actual object size distribution from direct imaging / Md. Iqbal Hossain in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10136–10146 Titre : Determination of actual object size distribution from direct imaging Type de document : texte imprimé Auteurs : Md. Iqbal Hossain, Auteur ; Tao Chen, Auteur ; Yanhui Yang, Auteur Année de publication : 2010 Article en page(s) : pp. 10136–10146 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Direct imaging Dynamic system Résumé : Direct imaging is a technique commonly used in the study of particle, bubble, and droplet size distribution in a dynamic system. Objects such as particles, bubbles, and droplets can be present at various distances from the imaging device when images are captured. Hence, the location of the object will need to be known in order to determine the actual size of an individual object. However, the location of the object cannot be determined from a single image. A single calibration scale defined at the focusing plane is normally used for the determination of all the object sizes from images. When the focus is close to the imaging device, the change in magnification with location is large. The size distribution obtained from the use of a single calibration scale would thus give a considerable deviation from the actual size distribution. In this study, a statistical method is proposed to reconstruct the actual object size distribution from the experimental object size distribution obtained from images using a single calibration scale defined at the focusing plane. Experiments are performed to validate the accuracy of the proposed method on the particle size distribution determination in a settling system. The stability of the proposed method is also analyzed theoretically for imaging devices with different depth-of-field (DOF), focusing location, and change in magnification with distance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900857m [article] Determination of actual object size distribution from direct imaging [texte imprimé] / Md. Iqbal Hossain, Auteur ; Tao Chen, Auteur ; Yanhui Yang, Auteur . - 2010 . - pp. 10136–10146. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10136–10146 Mots-clés : Direct imaging Dynamic system Résumé : Direct imaging is a technique commonly used in the study of particle, bubble, and droplet size distribution in a dynamic system. Objects such as particles, bubbles, and droplets can be present at various distances from the imaging device when images are captured. Hence, the location of the object will need to be known in order to determine the actual size of an individual object. However, the location of the object cannot be determined from a single image. A single calibration scale defined at the focusing plane is normally used for the determination of all the object sizes from images. When the focus is close to the imaging device, the change in magnification with location is large. The size distribution obtained from the use of a single calibration scale would thus give a considerable deviation from the actual size distribution. In this study, a statistical method is proposed to reconstruct the actual object size distribution from the experimental object size distribution obtained from images using a single calibration scale defined at the focusing plane. Experiments are performed to validate the accuracy of the proposed method on the particle size distribution determination in a settling system. The stability of the proposed method is also analyzed theoretically for imaging devices with different depth-of-field (DOF), focusing location, and change in magnification with distance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900857m

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Comparison of emulsification devices for the production of miniemulsions / Ula El-Jaby in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10147–10151 Titre : Comparison of emulsification devices for the production of miniemulsions Type de document : texte imprimé Auteurs : Ula El-Jaby, Auteur ; Michael Cunningham, Auteur ; Timothy F. L. McKenna, Auteur Année de publication : 2010 Article en page(s) : pp. 10147–10151 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Emulsification devices Miniemulsions Résumé : Droplets generated using ultrasonication, the rotor-stator, and static mixers have been investigated in terms of power and energy consumption, droplet distributions, and shear rates. It was observed that with energy costs being of similar orders of magnitude, the static mixers imposed less shear on the system making them the optimal choice for miniemulsification. Similarly, the absolute widths of the distributions for droplets generated with the sonicator and rotor-stator were larger than those generated with the static mixers and during polymerization underwent secondary nucleation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901005a [article] Comparison of emulsification devices for the production of miniemulsions [texte imprimé] / Ula El-Jaby, Auteur ; Michael Cunningham, Auteur ; Timothy F. L. McKenna, Auteur . - 2010 . - pp. 10147–10151. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10147–10151 Mots-clés : Emulsification devices Miniemulsions Résumé : Droplets generated using ultrasonication, the rotor-stator, and static mixers have been investigated in terms of power and energy consumption, droplet distributions, and shear rates. It was observed that with energy costs being of similar orders of magnitude, the static mixers imposed less shear on the system making them the optimal choice for miniemulsification. Similarly, the absolute widths of the distributions for droplets generated with the sonicator and rotor-stator were larger than those generated with the static mixers and during polymerization underwent secondary nucleation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901005a

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Hydrolysis and decomposition of cellulose in brönsted acidic ionic liquids under mild conditions / Ananda S. Amarasekara in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10152–10155 Titre : Hydrolysis and decomposition of cellulose in brönsted acidic ionic liquids under mild conditions Type de document : texte imprimé Auteurs : Ananda S. Amarasekara, Auteur ; Onome S. Owereh, Auteur Année de publication : 2010 Article en page(s) : pp. 10152–10155 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Brönsted acidic ionic liquids Cellulose dissolves Résumé : Cellulose dissolves in Brönsted acidic ionic liquids 1-(1-propylsulfonic)-3-methylimidazolium chloride and 1-(1-butylsulfonic)-3-methylimidazolium chloride up to 20 g/100 g ionic liquid by gentle mixing at room temperature. Hydrolysis of cellulose can be carried out in these ionic liquid solutions by the addition of 2.0 equiv of water per glucose unit of cellulose and heating the solution at 70 °C and at atmospheric pressure with or without preheating to give glucose along with other reducing sugars. The hydrolysis of Sigmacell cellulose (DP ∼ 450) in 1-(1-propylsulfonic)-3-methylimidazolium chloride produced the highest total reducing sugar (62%) and glucose (14%) yields and was attained in 1 h of preheating at 70 °C and 30 min of heating at 70 °C, after adding water. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901047u [article] Hydrolysis and decomposition of cellulose in brönsted acidic ionic liquids under mild conditions [texte imprimé] / Ananda S. Amarasekara, Auteur ; Onome S. Owereh, Auteur . - 2010 . - pp. 10152–10155. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10152–10155 Mots-clés : Brönsted acidic ionic liquids Cellulose dissolves Résumé : Cellulose dissolves in Brönsted acidic ionic liquids 1-(1-propylsulfonic)-3-methylimidazolium chloride and 1-(1-butylsulfonic)-3-methylimidazolium chloride up to 20 g/100 g ionic liquid by gentle mixing at room temperature. Hydrolysis of cellulose can be carried out in these ionic liquid solutions by the addition of 2.0 equiv of water per glucose unit of cellulose and heating the solution at 70 °C and at atmospheric pressure with or without preheating to give glucose along with other reducing sugars. The hydrolysis of Sigmacell cellulose (DP ∼ 450) in 1-(1-propylsulfonic)-3-methylimidazolium chloride produced the highest total reducing sugar (62%) and glucose (14%) yields and was attained in 1 h of preheating at 70 °C and 30 min of heating at 70 °C, after adding water. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901047u

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Butene oligomerization over phosphoric acid / Riaan Bekker in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10156–10162 Titre : Butene oligomerization over phosphoric acid : structural characterization of products Type de document : texte imprimé Auteurs : Riaan Bekker, Auteur ; Nicolaas M. Prinsloo, Auteur Année de publication : 2010 Article en page(s) : pp. 10156–10162 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Butene oligomerate Posphoric acid GC-MS techniques Résumé : In this study, the butene oligomerate produced over solid (SPA) and liquid phosphoric acid (LPA) was analyzed in detail using GC-MS techniques in conjunction with reported retention time data to identify the alkene isomers in the C6 to C8 fractions produced by the reaction. This information was used to quantify the oligomerate produced over liquid and solid phosphoric catalysts at different temperatures to identify subtle differences between the product distributions. It is hoped that this information will assist in future studies of the oligomerization reaction since several interesting trends that can be linked to previously proposed mechanisms were observed. Group classification of the identified alkenes according to the number of branches identified tetrasubstituted alkenes as compounds that form in large amounts during the reaction, but these are also removed through cracking faster than the other classes at higher temperatures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900210q [article] Butene oligomerization over phosphoric acid : structural characterization of products [texte imprimé] / Riaan Bekker, Auteur ; Nicolaas M. Prinsloo, Auteur . - 2010 . - pp. 10156–10162. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10156–10162 Mots-clés : Butene oligomerate Posphoric acid GC-MS techniques Résumé : In this study, the butene oligomerate produced over solid (SPA) and liquid phosphoric acid (LPA) was analyzed in detail using GC-MS techniques in conjunction with reported retention time data to identify the alkene isomers in the C6 to C8 fractions produced by the reaction. This information was used to quantify the oligomerate produced over liquid and solid phosphoric catalysts at different temperatures to identify subtle differences between the product distributions. It is hoped that this information will assist in future studies of the oligomerization reaction since several interesting trends that can be linked to previously proposed mechanisms were observed. Group classification of the identified alkenes according to the number of branches identified tetrasubstituted alkenes as compounds that form in large amounts during the reaction, but these are also removed through cracking faster than the other classes at higher temperatures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900210q

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