Preparation of silica-based inorganic-organic hybrid membrane via the sol-gel route

Silica-based inorganic-organic hybrid membranes have been prepared on porou s alpha -Al2O3 substrate (pore size, 2 mum) using tetraethoxysilane (TEOS) and phenyltrimethoxysilane (PTMOS) as precursors. The effects of sol synthe sis conditions on the processing and performance of deposited hybrid layers were observed. The thickness of the hybrid layers after three deposition c ycles is about 2 mum, estimated from their cross-section SEM micrographs. T he gas permselectivity of the hybrid membrane was characterized by O-2/N-2, CO2/N-2, and CO2/O-2 mixing gases, which was mainly governed by the surfac e diffusion at lower pressures and Knudson diffusion at higher pressures. T he introduction of phenyl groups can not only improve the selectivity of O- 2/N-2 and CO2/N-2, but also densify the membrane network.