Gas permeation properties and preparation of porous ceramic membrane by CVD method using siloxane compounds

Membranes have been developed for separation of specific gas from other gas molecules. Tube type ceramic was used for substrate. Silica membranes derived from tetramethoxysilane (TMOS), phenyltrimethoxysilane (PhTMS) and 3-aminopropylmethyldiethoxysilane (APMDES) were synthesized by chemical vapor deposition (CVD) method at 650 °C. Permeation experiments with H2, CO2 and N2 with ceramic membranes were performed to determine the gas transport characteristics. H2/N2 selectivities of TMOS, PhTMS and APMDES derived membranes were decreased by 1265, 633 and 100. And CO2/N2 selectivities of TMOS, PhTMS and APMDES derived membrane were increased by 3, 5 and 20. It is suggested that whether the intermediate contained living groups has a large effect on the enlargement of the pore size of amorphous silica membranes.

► The membranes are prepared by chemical vapor deposition method on ceramic support. ► The pore size of membranes was controlled by depositing silica layers of different precursors. ► Hydrogen selectivity was excellent in TMOS derived membrane. ► Carbon dioxide selectivity was excellent in APMDES derived membrane. ► The coefficient β determined activated diffusion effects in membranes.