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Preparation of Mesoporous ZnO Microspheres through a Membrane-Dispersion Microstructured Reactor and a Hydrothermal Treatment / Chunling Zhang in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13355-13361 Titre : Preparation of Mesoporous ZnO Microspheres through a Membrane-Dispersion Microstructured Reactor and a Hydrothermal Treatment Type de document : texte imprimé Auteurs : Chunling Zhang, Auteur ; Yujun Wang, Auteur ; Siwei Bi, Auteur Année de publication : 2012 Article en page(s) : pp. 13355-13361 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrothermal  treatment  Reactor  Dispersion  Microsphere  Preparation Résumé : Mesoporous ZnO microspheres with a diameter of about 10 μm were prepared through the combination of a membrane-dispersion microstructured reactor with a hydrothermal process. First, ZnSO4 reacted with NH4HCO3 in a membrane-dispersion reactor to produce the Zn5(CO3)2(OH)6 precursor, and then the precursor was treated at the temperature of 80 °C for 2 h to form the Zn5(CO3)2(OH)6 microspheres aided by the surfactant CTAB or F127; after the calcinations, mesoporous ZnO microspheres were obtained. The experimental results showed that the morphology of ZnO microspheres obtained using the membrane-dispersion microstructured reactor to mix the raw materials was better than that of those obtained using stirred tanks. Without surfactants and the hydrothermal treatment of the precursors, uniform ZnO microspheres could not be obtained. The SEM images showed that the monodispersed ZnO microspheres were assembled by the plates, and deeper observations revealed that these plates were aggregated by the ZnO nanorods formed by ZnO nanoparticles with a diameter of 9.0 nm. The adsorption-desorption isotherm curve indicated that the ZnO microspheres had mesoporous structures with an average pore diameter of 13.8 nm when using CTAB as the surfactant, and the specific surface area of the ZnO microspheres could reach 71.3 m2/g, much higher than that of ZnO nanoparticles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267493 [article] Preparation of Mesoporous ZnO Microspheres through a Membrane-Dispersion Microstructured Reactor and a Hydrothermal Treatment [texte imprimé] / Chunling Zhang, Auteur ; Yujun Wang, Auteur ; Siwei Bi, Auteur . - 2012 . - pp. 13355-13361. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13355-13361 Mots-clés : Hydrothermal  treatment  Reactor  Dispersion  Microsphere  Preparation Résumé : Mesoporous ZnO microspheres with a diameter of about 10 μm were prepared through the combination of a membrane-dispersion microstructured reactor with a hydrothermal process. First, ZnSO4 reacted with NH4HCO3 in a membrane-dispersion reactor to produce the Zn5(CO3)2(OH)6 precursor, and then the precursor was treated at the temperature of 80 °C for 2 h to form the Zn5(CO3)2(OH)6 microspheres aided by the surfactant CTAB or F127; after the calcinations, mesoporous ZnO microspheres were obtained. The experimental results showed that the morphology of ZnO microspheres obtained using the membrane-dispersion microstructured reactor to mix the raw materials was better than that of those obtained using stirred tanks. Without surfactants and the hydrothermal treatment of the precursors, uniform ZnO microspheres could not be obtained. The SEM images showed that the monodispersed ZnO microspheres were assembled by the plates, and deeper observations revealed that these plates were aggregated by the ZnO nanorods formed by ZnO nanoparticles with a diameter of 9.0 nm. The adsorption-desorption isotherm curve indicated that the ZnO microspheres had mesoporous structures with an average pore diameter of 13.8 nm when using CTAB as the surfactant, and the specific surface area of the ZnO microspheres could reach 71.3 m2/g, much higher than that of ZnO nanoparticles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267493

Preparation of monodispersed uniform silica spheres with large pore size for fast adsorption of proteins / Zheng Zhai in Industrial & engineering chemistry research, Vol. 49 N° 9 (Mai 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4162–4168 Titre : Preparation of monodispersed uniform silica spheres with large pore size for fast adsorption of proteins Type de document : texte imprimé Auteurs : Zheng Zhai, Auteur ; Yujun Wang, Auteur ; Yangcheng Lu, Auteur Année de publication : 2010 Article en page(s) : pp. 4162–4168 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adsorption  Pore  size  Preparation Résumé : In this paper, a “temperature-induced gelation” method, combined with microfluidic flows, has been developed to synthesize the uniform silica spheres with large pore structures for the fast adsorption of bovine serum albumin (BSA). The reversible-thermosentive property of methylcellulose (MC) and auxiliary function of poly(ethylene glycol) (PEG) were introduced to realize a fast gelation in a coaxial microfludic device. The effects of temperature and MC concentration on the gelation process were investigated by monitoring the change of viscosity of sol system over time. The silica spheres with different morphologies of internal structure were synthesized by adjusting the concentration of MC. The prepared silica spheres had large pore volumes (>2.0 mL/g) and an average mesopore diameter of >12 nm. Meanwhile, a large amount of macropores existed in the silica spheres. The bimodal mesopore-marcopore structure resulted in a high protein adsorption capacity (590 mg/g) and a fast adsorption rate (reaching equilibrium within 9 h). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732907 [article] Preparation of monodispersed uniform silica spheres with large pore size for fast adsorption of proteins [texte imprimé] / Zheng Zhai, Auteur ; Yujun Wang, Auteur ; Yangcheng Lu, Auteur . - 2010 . - pp. 4162–4168. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4162–4168 Mots-clés : Adsorption  Pore  size  Preparation Résumé : In this paper, a “temperature-induced gelation” method, combined with microfluidic flows, has been developed to synthesize the uniform silica spheres with large pore structures for the fast adsorption of bovine serum albumin (BSA). The reversible-thermosentive property of methylcellulose (MC) and auxiliary function of poly(ethylene glycol) (PEG) were introduced to realize a fast gelation in a coaxial microfludic device. The effects of temperature and MC concentration on the gelation process were investigated by monitoring the change of viscosity of sol system over time. The silica spheres with different morphologies of internal structure were synthesized by adjusting the concentration of MC. The prepared silica spheres had large pore volumes (>2.0 mL/g) and an average mesopore diameter of >12 nm. Meanwhile, a large amount of macropores existed in the silica spheres. The bimodal mesopore-marcopore structure resulted in a high protein adsorption capacity (590 mg/g) and a fast adsorption rate (reaching equilibrium within 9 h). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732907

Preparation of pseudoboehmite with a large pore volume and a large pore size by using a membrane-dispersion microstructured reactor through the reaction of CO2 and a NaAlO2 solution / Yujun Wang in Industrial & engineering chemistry research, Vol. 50 N° 7 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 3889–3894 Titre : Preparation of pseudoboehmite with a large pore volume and a large pore size by using a membrane-dispersion microstructured reactor through the reaction of CO2 and a NaAlO2 solution Type de document : texte imprimé Auteurs : Yujun Wang, Auteur ; Dengqing Xu, Auteur ; Haitao Sun, Auteur Année de publication : 2011 Article en page(s) : pp. 3889–3894 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Membrane  dispersion  microstructured  reactor Résumé : In this work, a membrane-dispersion microstructured reactor was specially designed to prepare PB (pseudoboehmite) with a large pore volume and a large pore size through the reaction of CO2 and an aqueous solution of NaAlO2. Tiny crystals of PB and a suitable template are necessary for generating large pore diameter and large pore volume. In this reactor, the tiny crystals could be obtained by increasing the mass transfer rate between the gas phase and the liquid phase through dispersing the CO2 gas into many microbubbles, and these microbubbles could act as a template to increase the pore volume. The effects of the final pH of the aqueous solution, the concentrations of raw materials, and the flow rate of the gas phase on pore properties of products were investigated. The results showed that when the final pH of the aqueous solution was between 10.5 and 9.4, pure PB could be obtained, and the crystal size of PB was about 2.3 nm. In addition, the specific surface area, the pore volume, and the average pore diameter of PB reached 548.5 m2/g, 2.22 mL/g, and 16.2 nm, respectively, under optimal conditions; these values were much higher than those prepared in the stirred tank. After calcinations of PB at 550 °C, the γ -Al2O3 powder obtained also yielded large pore volume and large average pore diameter. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101629g [article] Preparation of pseudoboehmite with a large pore volume and a large pore size by using a membrane-dispersion microstructured reactor through the reaction of CO2 and a NaAlO2 solution [texte imprimé] / Yujun Wang, Auteur ; Dengqing Xu, Auteur ; Haitao Sun, Auteur . - 2011 . - pp. 3889–3894. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 3889–3894 Mots-clés : Membrane  dispersion  microstructured  reactor Résumé : In this work, a membrane-dispersion microstructured reactor was specially designed to prepare PB (pseudoboehmite) with a large pore volume and a large pore size through the reaction of CO2 and an aqueous solution of NaAlO2. Tiny crystals of PB and a suitable template are necessary for generating large pore diameter and large pore volume. In this reactor, the tiny crystals could be obtained by increasing the mass transfer rate between the gas phase and the liquid phase through dispersing the CO2 gas into many microbubbles, and these microbubbles could act as a template to increase the pore volume. The effects of the final pH of the aqueous solution, the concentrations of raw materials, and the flow rate of the gas phase on pore properties of products were investigated. The results showed that when the final pH of the aqueous solution was between 10.5 and 9.4, pure PB could be obtained, and the crystal size of PB was about 2.3 nm. In addition, the specific surface area, the pore volume, and the average pore diameter of PB reached 548.5 m2/g, 2.22 mL/g, and 16.2 nm, respectively, under optimal conditions; these values were much higher than those prepared in the stirred tank. After calcinations of PB at 550 °C, the γ -Al2O3 powder obtained also yielded large pore volume and large average pore diameter. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101629g