Abstract: The silica membranes supported by α-alumina hollow fibers were prepared, and their structures, appearance and pore size distribution were characterized by small X-ray diffraction(SXRD), high-resolution transmission electron microscopy(HRTEM), FTIR, SEM and nitrogen adsorption isotherm measurement. The results of SXRD and HRTEM show that the obtained membranes are partially ordered materials. SEM images indicate that the membranes supported by α-alumina hollow fibers are defect-free. Gas permeability test suggests that the membranes possess gas selectivity, and the separation factors for H₂/N₂ and CH₄/N₂ are 2.25 and 1.56 at 0.1 MPa, respectively. It is shown that the gas diffusion through the membrane is governed by Knudsen diffusion mechanism. Nitrogen adsorption isotherm measurement indicates that the most concentrative pore diameter is smaller than 3.34 nm, pore volume and specific surface area of an unsupported membrane after calcinations at 500 ℃ is 0.43 mL/g and 919.8 m²/g, respectively.

Key words: Silica membranes, Hollow fiber, Preparation, Structure