화학공학소재연구정보센터
Journal of Membrane Science, Vol.383, No.1-2, 152-158, 2011
Pore-size-controlled silica membranes with disiloxane alkoxides for gas separation
Pore-size-controlled silica membranes were prepared using hexaethoxy disiloxane (HEDS) by a "spacer" technique, which is a novel strategy to control the pore size of silica membranes using bridged alkoxides. HEDS-derived silica gel powders prepared with acid and base catalysts were microporous and mesoporous, respectively. HEDS-derived silica membranes prepared from HCl-catalyzed sol showed high H(2) permeance (0.73-2.0 x 10(-6) mol m(-2) s(-1) Pa(-1)) with low H(2)/N(2) (similar to 20) and high H(2)/SF(6) perm-selectivity (similar to 2000). Pore size by single gas permeation and normalized Knudsen-based permeance (NKP) showed that silica membranes with bridged alkoxides had a loose amorphous silica structure. Judging from NKP fitting curves for tetraethylorthosilicate (TEOS), HEDS, tetraethoxydimethyl disiloxane (TEDMDS), and bis(triethoxysily1) ethane (BTESE)-derived silica membranes, the order was TEOS < HEDS < BTESE approximate to TEDMDS. These results suggested that the pore size of silica membranes can be tuned with various structured alkoxides of di-silicon. (C) 2011 Elsevier B.V. All rights reserved.