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

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

Fabrication of bimodal porous CaTiO3 microspheres using composite agarose/CaCO3 beads as template / Kai-Feng Du in Industrial & engineering chemistry research, Vol. 49 N° 24 (Décembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12560–12566 Titre : Fabrication of bimodal porous CaTiO3 microspheres using composite agarose/CaCO3 beads as template Type de document : texte imprimé Auteurs : Kai-Feng Du, Auteur ; Xiao-Yan Dong, Auteur ; Yan Sun, Auteur Année de publication : 2011 Article en page(s) : pp. 12560–12566 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microspheres  Bimodal  porous Résumé : Agarose gel entrapping CaCO3 granules is used for the synthesis of bimodal porous CaTiO3 beads by a method that combines a sol−gel process and solid phase reaction, in which CaCO3 (1.05 μm) performed as both calcium resource and porogen for creating macropores. The amount of CaCO3 granules embedded in agarose gel is varied from 0 to 16 wt %, and the macropores on the surface and in the inner of final CaTiO3 beads are investigated. It is found that the addition of 12 wt % of CaCO3 produced CaTiO3 beads that present interconnected macropores of about 745 ± 20 nm. The calcination temperature affects the surface area, mesopore size, phase state, and crystalline size of the CaTiO3 beads. By calcination at 450 °C, the CaTiO3 beads prepared by the addition of 12 wt % CaCO3 are amorphous with an average pore size of 9 nm and possess a high surface area of about 225 m2 g−1. With an increase of temperature to 600, 750, and 900 °C, the CaTiO3 is transformed into perovskite in size of about 32, 34, and 37 nm with mesopores of about 20, 23, and 24 nm, respectively, and its specific surface area decreases below 20 m2 g−1. The bimodal porous CaTiO3 beads of about 15 μm are packed into a column for investigating its chromatographic performance. The column shows much higher column efficiency than that packed with CaTiO3 beads without removal of the porogen. The remarkably high separation performance is attributed to the unique surface property and interconnected macropores present in the CaTiO3 beads. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901727s [article] Fabrication of bimodal porous CaTiO3 microspheres using composite agarose/CaCO3 beads as template [texte imprimé] / Kai-Feng Du, Auteur ; Xiao-Yan Dong, Auteur ; Yan Sun, Auteur . - 2011 . - pp. 12560–12566. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12560–12566 Mots-clés : Microspheres  Bimodal  porous Résumé : Agarose gel entrapping CaCO3 granules is used for the synthesis of bimodal porous CaTiO3 beads by a method that combines a sol−gel process and solid phase reaction, in which CaCO3 (1.05 μm) performed as both calcium resource and porogen for creating macropores. The amount of CaCO3 granules embedded in agarose gel is varied from 0 to 16 wt %, and the macropores on the surface and in the inner of final CaTiO3 beads are investigated. It is found that the addition of 12 wt % of CaCO3 produced CaTiO3 beads that present interconnected macropores of about 745 ± 20 nm. The calcination temperature affects the surface area, mesopore size, phase state, and crystalline size of the CaTiO3 beads. By calcination at 450 °C, the CaTiO3 beads prepared by the addition of 12 wt % CaCO3 are amorphous with an average pore size of 9 nm and possess a high surface area of about 225 m2 g−1. With an increase of temperature to 600, 750, and 900 °C, the CaTiO3 is transformed into perovskite in size of about 32, 34, and 37 nm with mesopores of about 20, 23, and 24 nm, respectively, and its specific surface area decreases below 20 m2 g−1. The bimodal porous CaTiO3 beads of about 15 μm are packed into a column for investigating its chromatographic performance. The column shows much higher column efficiency than that packed with CaTiO3 beads without removal of the porogen. The remarkably high separation performance is attributed to the unique surface property and interconnected macropores present in the CaTiO3 beads. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901727s

Synthesis of bimodal porous titania beads and their potential in liquid chromatography / Kai-Feng Du in Industrial & engineering chemistry research, Vol. 50 N° 10 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6101-6108 Titre : Synthesis of bimodal porous titania beads and their potential in liquid chromatography Type de document : texte imprimé Auteurs : Kai-Feng Du, Auteur ; Min Yan, Auteur ; Hang Song, Auteur Année de publication : 2011 Article en page(s) : pp. 6101-6108 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid  chromatography Résumé : Bimodal porous titania beads were synthesized from titania nanocrystals of about 34 nm by a method that combines particles agglomeration and sol-gel templating process. The structure properties of porous titania beads were investigated, and the results indicated that the porous titania beads in size of about 15 μm are pure anatase phase and featured by two types of pores with macropores centered at about 200 nm and mesopores smaller than 10 nm. The bimodal pore structure is attributed to hard aggregates of titania particles with different size. In particular, the larger titania nanocrystals agglomerate into macropores and the smaller ones from crystal growth of coated titania into mesopores. Finally, after cation modification, the bimodal porous adsorbents (BPA) were evaluated for investigating chromatographic performance and compared to microporous ones (MPA). It was observed that static and dynamic adsorption capacities of cytochrome C on BPA are both larger than that on MPA. Moreover, the BPApacked column shows better column efficiency than the MPA packed one in test flow rates. Therefore, we demonstrated that the BPA occupies more advantages over the other one and is expected for potential application in chromatography. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158908 [article] Synthesis of bimodal porous titania beads and their potential in liquid chromatography [texte imprimé] / Kai-Feng Du, Auteur ; Min Yan, Auteur ; Hang Song, Auteur . - 2011 . - pp. 6101-6108. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6101-6108 Mots-clés : Liquid  chromatography Résumé : Bimodal porous titania beads were synthesized from titania nanocrystals of about 34 nm by a method that combines particles agglomeration and sol-gel templating process. The structure properties of porous titania beads were investigated, and the results indicated that the porous titania beads in size of about 15 μm are pure anatase phase and featured by two types of pores with macropores centered at about 200 nm and mesopores smaller than 10 nm. The bimodal pore structure is attributed to hard aggregates of titania particles with different size. In particular, the larger titania nanocrystals agglomerate into macropores and the smaller ones from crystal growth of coated titania into mesopores. Finally, after cation modification, the bimodal porous adsorbents (BPA) were evaluated for investigating chromatographic performance and compared to microporous ones (MPA). It was observed that static and dynamic adsorption capacities of cytochrome C on BPA are both larger than that on MPA. Moreover, the BPApacked column shows better column efficiency than the MPA packed one in test flow rates. Therefore, we demonstrated that the BPA occupies more advantages over the other one and is expected for potential application in chromatography. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158908