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Ce0.8Sm0.2O2−δ−La0.8Sr0.2MnO3−δ dual-phase omposite hollow fiber membrane for oxygen separation / Wei Li in Industrial & engineering chemistry research, Vol. 48 N° 12 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5789–5793 Titre : Ce0.8Sm0.2O2−δ−La0.8Sr0.2MnO3−δ dual-phase omposite hollow fiber membrane for oxygen separation Type de document : texte imprimé Auteurs : Wei Li, Auteur ; Ting-Fang Tian, Auteur ; Feng-Yuan Shi, Auteur Année de publication : 2009 Article en page(s) : pp. 5789–5793 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Dense  ceramic  oxygen  separation  membrane  Cryogenic  distillation  process Résumé : The dense ceramic oxygen separation membrane holds promise to reduce the oxygen production cost significantly over the current mature cryogenic distillation process. Preparation of membranes in hollow fiber geometry is expected to lead to a remarkable increase in the oxygen production capacity of the membrane unit. Gas-tight Ce0.8Sm0.2O2−δ−La0.8Sr0.2MnO3−δ dual-phase composite hollow fibers were prepared by a phase-inversion/sintering technique. A stable oxygen permeation rate of 3.2 × 10−7 mol·cm−2·s−1 was measured under air/He gradient at 950 °C, and 3.0 × 10−7 mol·cm−2·s−1 was found under air/CO2 gradient. It was also found that oxygen permeation through the hollow fiber can be well-described by the Wagner equation and assuming that the gas flow in the core of the fiber conforms to the plug flow model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002624 [article] Ce0.8Sm0.2O2−δ−La0.8Sr0.2MnO3−δ dual-phase omposite hollow fiber membrane for oxygen separation [texte imprimé] / Wei Li, Auteur ; Ting-Fang Tian, Auteur ; Feng-Yuan Shi, Auteur . - 2009 . - pp. 5789–5793. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5789–5793 Mots-clés : Dense  ceramic  oxygen  separation  membrane  Cryogenic  distillation  process Résumé : The dense ceramic oxygen separation membrane holds promise to reduce the oxygen production cost significantly over the current mature cryogenic distillation process. Preparation of membranes in hollow fiber geometry is expected to lead to a remarkable increase in the oxygen production capacity of the membrane unit. Gas-tight Ce0.8Sm0.2O2−δ−La0.8Sr0.2MnO3−δ dual-phase composite hollow fibers were prepared by a phase-inversion/sintering technique. A stable oxygen permeation rate of 3.2 × 10−7 mol·cm−2·s−1 was measured under air/He gradient at 950 °C, and 3.0 × 10−7 mol·cm−2·s−1 was found under air/CO2 gradient. It was also found that oxygen permeation through the hollow fiber can be well-described by the Wagner equation and assuming that the gas flow in the core of the fiber conforms to the plug flow model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002624

Comparative Study in Liquid-Phase Heterogeneous Photocatalysis / Dong Li in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8397–8405 Titre : Comparative Study in Liquid-Phase Heterogeneous Photocatalysis : Model for Photoreactor Scale-Up Type de document : texte imprimé Auteurs : Dong Li, Auteur ; Kui Xiong, Auteur ; Wei Li, Auteur Année de publication : 2010 Article en page(s) : pp. 8397–8405 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Photoreactors  Photocatalysis Résumé : A scale-up model for photoreactors based on a comparative study of the photocatalytic efficiency of suspended and immobilized systems was developed. The model is independent of reactor size and configurations, and it assumes that photocatalytic efficiency is the same when normalized per unit of illuminated catalyst area in both systems. In all cases, phenol/TiO2 (Degussa P25) was selected as the photodegradation system. First, a kinetic model was built in an immobilized system based on the corresponding experimental data, and then predicted rates of phenol degradation in the suspended system were calculated using the above kinetic model combined with a simplified radiation model, which was expressed as an apparent form of the Lambert law. Second, to obtain experimental rates, experiments conducted in the suspended system were carried out under the same conditions used in the immobilized system. Ratios between experimental rates and predicted rates were obtained, revealing the differences in efficiency between the suspended and immobilized systems. The typical value of the ratio was 2.5−9.2, suggesting that the efficiency of the suspended system was 2.5−9.2 times higher than that of the immobilized system. The ratio decreased with increasing concentrations of both phenol and catalyst. When the catalyst concentration and initial concentration of phenol were set, the ratio became constant within the range of the light intensity of 1.71−3.60 mW cm−2. Finally, for photoreactor scale-up, the proposed model was validated in a larger photoreactor operated in the suspended system, and good agreements were obtained with errors less than 5%. This methodology provides an alternative to the scale-up of photoreactors, which allows for easier engineering applications. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100277g [article] Comparative Study in Liquid-Phase Heterogeneous Photocatalysis : Model for Photoreactor Scale-Up [texte imprimé] / Dong Li, Auteur ; Kui Xiong, Auteur ; Wei Li, Auteur . - 2010 . - pp. 8397–8405. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8397–8405 Mots-clés : Photoreactors  Photocatalysis Résumé : A scale-up model for photoreactors based on a comparative study of the photocatalytic efficiency of suspended and immobilized systems was developed. The model is independent of reactor size and configurations, and it assumes that photocatalytic efficiency is the same when normalized per unit of illuminated catalyst area in both systems. In all cases, phenol/TiO2 (Degussa P25) was selected as the photodegradation system. First, a kinetic model was built in an immobilized system based on the corresponding experimental data, and then predicted rates of phenol degradation in the suspended system were calculated using the above kinetic model combined with a simplified radiation model, which was expressed as an apparent form of the Lambert law. Second, to obtain experimental rates, experiments conducted in the suspended system were carried out under the same conditions used in the immobilized system. Ratios between experimental rates and predicted rates were obtained, revealing the differences in efficiency between the suspended and immobilized systems. The typical value of the ratio was 2.5−9.2, suggesting that the efficiency of the suspended system was 2.5−9.2 times higher than that of the immobilized system. The ratio decreased with increasing concentrations of both phenol and catalyst. When the catalyst concentration and initial concentration of phenol were set, the ratio became constant within the range of the light intensity of 1.71−3.60 mW cm−2. Finally, for photoreactor scale-up, the proposed model was validated in a larger photoreactor operated in the suspended system, and good agreements were obtained with errors less than 5%. This methodology provides an alternative to the scale-up of photoreactors, which allows for easier engineering applications. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100277g

Effect of polymer granules on the electrostatic behavior in gas−solid fluidized beds / Xianbo Yu in Industrial & engineering chemistry research, Vol. 49 N° 1 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 1 (Janvier 2010) . - pp. 132–139 Titre : Effect of polymer granules on the electrostatic behavior in gas−solid fluidized beds Type de document : texte imprimé Auteurs : Xianbo Yu, Auteur ; Wei Li, Auteur ; Yi Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 132–139 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Effect--Polymer  Granules--Electrostatic--Gas−Solid--Fluidized  Beds Résumé : Granules polymers electrostatic behavior in a fluidized bed can be complicated by the differences in catalyst residue and surface properties among them. Electrically charged particles cling together in large aggregates and adhere to the wall of the apparatus. Polymer particles with the same chemical composition but different sizes would have their own special contributions to the generation of static charges. It is improtant to understand polymer particles role on electrostatic charge generation and dissipation. Experiments are carried out in a gas−solid fluidized bed with nitrogen as the fluidization gas to determine the relationship between the electrostatic charge level and the size of the polyethylene granule. By measuring the electrostatic potentials at different bed axial heights, it is found that the electric field inside the bed is significantly influenced by the size, weight fractions, and catalyst residue of added granular polyethylene. Consequently, an impact factor of granules (Fb) is proposed to study the influence of particle size and the weight percent of the residual catalyst to the electrostatic potentials. And it is found that the greater the degree of fineness of the granules, the more percentage of the residual catalyst in the particles, which results in the stronger affect on the electrostatic behavior in the fluidized bed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017077 [article] Effect of polymer granules on the electrostatic behavior in gas−solid fluidized beds [texte imprimé] / Xianbo Yu, Auteur ; Wei Li, Auteur ; Yi Xu, Auteur . - 2010 . - pp. 132–139. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 1 (Janvier 2010) . - pp. 132–139 Mots-clés : Effect--Polymer  Granules--Electrostatic--Gas−Solid--Fluidized  Beds Résumé : Granules polymers electrostatic behavior in a fluidized bed can be complicated by the differences in catalyst residue and surface properties among them. Electrically charged particles cling together in large aggregates and adhere to the wall of the apparatus. Polymer particles with the same chemical composition but different sizes would have their own special contributions to the generation of static charges. It is improtant to understand polymer particles role on electrostatic charge generation and dissipation. Experiments are carried out in a gas−solid fluidized bed with nitrogen as the fluidization gas to determine the relationship between the electrostatic charge level and the size of the polyethylene granule. By measuring the electrostatic potentials at different bed axial heights, it is found that the electric field inside the bed is significantly influenced by the size, weight fractions, and catalyst residue of added granular polyethylene. Consequently, an impact factor of granules (Fb) is proposed to study the influence of particle size and the weight percent of the residual catalyst to the electrostatic potentials. And it is found that the greater the degree of fineness of the granules, the more percentage of the residual catalyst in the particles, which results in the stronger affect on the electrostatic behavior in the fluidized bed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017077

Immobilizing penicillin G acylase using silica-supported ionic liquids / Huacong Zhou in Industrial & engineering chemistry research, Vol. 51 N° 40 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 40 (Octobre 2012) . - pp. 13173–13181 Titre : Immobilizing penicillin G acylase using silica-supported ionic liquids : The effects of ionic liquid loadings Type de document : texte imprimé Auteurs : Huacong Zhou, Auteur ; Liangrong Yang, Auteur ; Wei Li, Auteur Année de publication : 2012 Article en page(s) : pp. 13173–13181 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Loading  Ionic  liquid Résumé : The supported ionic liquids (SILs) were prepared via immobilizing silane-functionalized ionic liquids (IL) onto the monodispersive silica nanoparticles, and the composite material was then applied in the immobilization of penicillin G acylase (PGA, EC 3.5.1.11), an important industrial enzyme for the production of semisynthetic antibiotics. This was a novel approach of immobilizing PGA proposed in our previous report, in which we had studied the effects of IL types on the performance of this novel support. Here, we focused on the effects of IL loading on the properties of the SILs and their performance in PGA immobilization. The effects of silica sizes and routes of preparing SILs (the solvent route and the sol-gel route) on IL loading were investigated. The results showed that (1) the IL loading could be tuned efficiently by changing the silica sizes. (2) As compared with the solvent route, the sol-gel route is more simple, time-saving, and ecofriendly in operation. What's more, it has a higher IL loading. Among the factors affecting the IL loading, the reaction time was the most feasible factor to control to tune the IL loading, as compared with the temperature and the dosage of ILs. (3) With the increase of IL loading, the surface ζ-potential of silicas changed from negative to positive, and the isoelectronic point (IEP) increased accordingly, which caused the decrease of the protein loading but the increase of apparent and specific activity. A reusability experiment showed that the sol-gel 1 sample maintained approximately 55% of the initial activity even after 10 consecutive operation cycles under the experimental conditions. This activity was 3.7 times higher than that of the sol-gel 2 sample. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26451467 [article] Immobilizing penicillin G acylase using silica-supported ionic liquids : The effects of ionic liquid loadings [texte imprimé] / Huacong Zhou, Auteur ; Liangrong Yang, Auteur ; Wei Li, Auteur . - 2012 . - pp. 13173–13181. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 40 (Octobre 2012) . - pp. 13173–13181 Mots-clés : Loading  Ionic  liquid Résumé : The supported ionic liquids (SILs) were prepared via immobilizing silane-functionalized ionic liquids (IL) onto the monodispersive silica nanoparticles, and the composite material was then applied in the immobilization of penicillin G acylase (PGA, EC 3.5.1.11), an important industrial enzyme for the production of semisynthetic antibiotics. This was a novel approach of immobilizing PGA proposed in our previous report, in which we had studied the effects of IL types on the performance of this novel support. Here, we focused on the effects of IL loading on the properties of the SILs and their performance in PGA immobilization. The effects of silica sizes and routes of preparing SILs (the solvent route and the sol-gel route) on IL loading were investigated. The results showed that (1) the IL loading could be tuned efficiently by changing the silica sizes. (2) As compared with the solvent route, the sol-gel route is more simple, time-saving, and ecofriendly in operation. What's more, it has a higher IL loading. Among the factors affecting the IL loading, the reaction time was the most feasible factor to control to tune the IL loading, as compared with the temperature and the dosage of ILs. (3) With the increase of IL loading, the surface ζ-potential of silicas changed from negative to positive, and the isoelectronic point (IEP) increased accordingly, which caused the decrease of the protein loading but the increase of apparent and specific activity. A reusability experiment showed that the sol-gel 1 sample maintained approximately 55% of the initial activity even after 10 consecutive operation cycles under the experimental conditions. This activity was 3.7 times higher than that of the sol-gel 2 sample. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26451467

Improving the stability of immobilized penicillin G acylase via the modification of supports with ionic liquids / Huacong Zhou in Industrial & engineering chemistry research, Vol. 51 N° 12 (Mars 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 12 (Mars 2012) . - pp. 4582–4590 Titre : Improving the stability of immobilized penicillin G acylase via the modification of supports with ionic liquids Type de document : texte imprimé Auteurs : Huacong Zhou, Auteur ; Liangrong Yang, Auteur ; Wei Li, Auteur Année de publication : 2012 Article en page(s) : pp. 4582–4590 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic  liquids  Nanoparticles Résumé : With the aim of improving the stability of penicillin G acylase (PGA), functional ionic liquids (ILs) were used to modify the surface chemistry of the supports on which they were physically adsorbed. Four kinds of ILs—specifically, 1-methyl-3-(triethoxysilylpropyl)-imidazolium salts, with Cl–, BF4–, PF6–, and Tf2N– as the anions (IL-Cl–, BF4–, PF6–, and Tf2N–, respectively)—were used to tune the hydrophilic or hydrophobic properties of the ILs. The synthesized ILs were first immobilized on magnetic silica nanoparticles (Fe3O4/SiO2), and the composite material (Fe3O4/SiO2–IL) was then applied to immobilize PGA via physical adsorption. The amount of protein loading, the specific activity, the immobilization yield, and the stability of immobilized PGA were investigated to evaluate the effects of the ILs on the PGA immobilization. The results showed that PGA immobilized on Fe3O4/SiO2–ILs was more stable than that immobilized on Fe3O4/SiO2 with no IL modification. Among the four kinds of ILs tested, the hydrophilic ILs (IL-Cl–, and IL-BF4–) were superior to the hydrophobic ones (IL-PF6–, and IL-Tf2N–) for PGA immobilization. The reusability of the immobilized PGA on Fe3O4/SiO2–IL (BF4–) was evaluated; a high residual activity (70% of the initial activity) was observed after 9 consecutive operation cycles under the experimental conditions. This activity was 1.8 times higher than that of immobilized PGA on naked Fe3O4/SiO2 (40%). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202745c [article] Improving the stability of immobilized penicillin G acylase via the modification of supports with ionic liquids [texte imprimé] / Huacong Zhou, Auteur ; Liangrong Yang, Auteur ; Wei Li, Auteur . - 2012 . - pp. 4582–4590. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 12 (Mars 2012) . - pp. 4582–4590 Mots-clés : Ionic  liquids  Nanoparticles Résumé : With the aim of improving the stability of penicillin G acylase (PGA), functional ionic liquids (ILs) were used to modify the surface chemistry of the supports on which they were physically adsorbed. Four kinds of ILs—specifically, 1-methyl-3-(triethoxysilylpropyl)-imidazolium salts, with Cl–, BF4–, PF6–, and Tf2N– as the anions (IL-Cl–, BF4–, PF6–, and Tf2N–, respectively)—were used to tune the hydrophilic or hydrophobic properties of the ILs. The synthesized ILs were first immobilized on magnetic silica nanoparticles (Fe3O4/SiO2), and the composite material (Fe3O4/SiO2–IL) was then applied to immobilize PGA via physical adsorption. The amount of protein loading, the specific activity, the immobilization yield, and the stability of immobilized PGA were investigated to evaluate the effects of the ILs on the PGA immobilization. The results showed that PGA immobilized on Fe3O4/SiO2–ILs was more stable than that immobilized on Fe3O4/SiO2 with no IL modification. Among the four kinds of ILs tested, the hydrophilic ILs (IL-Cl–, and IL-BF4–) were superior to the hydrophobic ones (IL-PF6–, and IL-Tf2N–) for PGA immobilization. The reusability of the immobilized PGA on Fe3O4/SiO2–IL (BF4–) was evaluated; a high residual activity (70% of the initial activity) was observed after 9 consecutive operation cycles under the experimental conditions. This activity was 1.8 times higher than that of immobilized PGA on naked Fe3O4/SiO2 (40%). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202745c