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Effect of midsynthesis addition of silica to the synthesis medium on the properties of MFI - type zeolite membranes / Belma Soydas in Industrial & engineering chemistry research, Vol. 49 N° 11 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 11 (Juin 2010) . - pp. 5407–5414 Titre : Effect of midsynthesis addition of silica to the synthesis medium on the properties of MFI - type zeolite membranes Type de document : texte imprimé Auteurs : Belma Soydas, Auteur ; Halil Kalipcilar, Auteur ; Ali Culfaz, Auteur Année de publication : 2010 Article en page(s) : pp. 5407–5414 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Zeolite  Membranes Résumé : Thin zeolite membranes of MFI type were prepared on α-Al2O3 supports by midsynthesis addition of silica in a recirculating flow system at 95 °C. The synthesis was started with the batch composition of 80SiO2:30TPAOH:1500H2O which was changed to 80SiO2:9TPAOH:1500H2O by addition of silica after 24, 48, or 72 h. Compared to synthesis at constant composition, it is possible to affect the rates of nucleation and crystal growth to obtain membranes with better quality by changing the overall composition of the medium during the membrane synthesis. The membranes produced with and without midsynthesis addition of silica have n-C4H10/i-C4H10 ideal selectivities of 47 and 8 at 100 °C, respectively. Among these membranes, the ones formed with midsynthesis addition of silica at 24 h yielded the highest n-C4H10/CH4 separation selectivities, which were over 20 at 25 °C. The time at which the silica is introduced to the synthesis medium is critical for the membrane quality. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902024h [article] Effect of midsynthesis addition of silica to the synthesis medium on the properties of MFI - type zeolite membranes [texte imprimé] / Belma Soydas, Auteur ; Halil Kalipcilar, Auteur ; Ali Culfaz, Auteur . - 2010 . - pp. 5407–5414. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 11 (Juin 2010) . - pp. 5407–5414 Mots-clés : Zeolite  Membranes Résumé : Thin zeolite membranes of MFI type were prepared on α-Al2O3 supports by midsynthesis addition of silica in a recirculating flow system at 95 °C. The synthesis was started with the batch composition of 80SiO2:30TPAOH:1500H2O which was changed to 80SiO2:9TPAOH:1500H2O by addition of silica after 24, 48, or 72 h. Compared to synthesis at constant composition, it is possible to affect the rates of nucleation and crystal growth to obtain membranes with better quality by changing the overall composition of the medium during the membrane synthesis. The membranes produced with and without midsynthesis addition of silica have n-C4H10/i-C4H10 ideal selectivities of 47 and 8 at 100 °C, respectively. Among these membranes, the ones formed with midsynthesis addition of silica at 24 h yielded the highest n-C4H10/CH4 separation selectivities, which were over 20 at 25 °C. The time at which the silica is introduced to the synthesis medium is critical for the membrane quality. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902024h

Synthesis of ZSM-5-type zeolite membranes on porous disks loaded with different amounts of seed / Eser Eser Dinçer in Industrial & engineering chemistry research, Vol. 47 n°14 (Juillet 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4743-4749 Titre : Synthesis of ZSM-5-type zeolite membranes on porous disks loaded with different amounts of seed Type de document : texte imprimé Auteurs : Eser Eser Dinçer, Auteur ; Halil Kalıpçılar, Auteur ; Ali Culfaz, Auteur Année de publication : 2008 Article en page(s) : p. 4743-4749 Note générale : Bibliogr. p. 4748-4749 Langues : Anglais (eng) Mots-clés : ZSM-5-type  zeolite  membranes;  Alumina  supports Résumé : ZSM-5-type zeolite membranes were synthesized at 130 °C on alumina supports coated with seed crystals by vacuum seeding. Compact and uniform ZSM-5 layers were formed on the support surfaces when the amount of seed was less than 1 mg/cm2. Higher loading of seed crystals resulted in an asymmetric structure with a compact and uniform ZSM-5 layer on top, the support at the bottom, and the seed layer in between. Fifty-one membranes were prepared on supports coated with different amounts of seed. About 70% of the membranes synthesized on seeded supports were impermeable to nitrogen before calcination, whereas all nine membranes synthesized on plain supports were permeable to nitrogen before calcination. One-third of the membranes synthesized on seeded supports had N2/SF6 ideal selectivity higher than the quality criterion of 40 after calcination. Membranes with high N2/SF6 ideal selectivity also showed high n-C4H10/i-C4H10 separation selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715411 [article] Synthesis of ZSM-5-type zeolite membranes on porous disks loaded with different amounts of seed [texte imprimé] / Eser Eser Dinçer, Auteur ; Halil Kalıpçılar, Auteur ; Ali Culfaz, Auteur . - 2008 . - p. 4743-4749. Bibliogr. p. 4748-4749 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4743-4749 Mots-clés : ZSM-5-type  zeolite  membranes;  Alumina  supports Résumé : ZSM-5-type zeolite membranes were synthesized at 130 °C on alumina supports coated with seed crystals by vacuum seeding. Compact and uniform ZSM-5 layers were formed on the support surfaces when the amount of seed was less than 1 mg/cm2. Higher loading of seed crystals resulted in an asymmetric structure with a compact and uniform ZSM-5 layer on top, the support at the bottom, and the seed layer in between. Fifty-one membranes were prepared on supports coated with different amounts of seed. About 70% of the membranes synthesized on seeded supports were impermeable to nitrogen before calcination, whereas all nine membranes synthesized on plain supports were permeable to nitrogen before calcination. One-third of the membranes synthesized on seeded supports had N2/SF6 ideal selectivity higher than the quality criterion of 40 after calcination. Membranes with high N2/SF6 ideal selectivity also showed high n-C4H10/i-C4H10 separation selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715411