中空纤维担载氧化硅膜的制备及结构研究

采用SXRD,HRTEM,FTIR,SEM和氮气吸附等测试手段对膜结构、形貌、孔径及其分布进行了表征.SXRD和HRTEM结果显示,所制备的膜具有短程有序结构.SEM分析发现膜表面完整.气体渗透实验表明,担载膜具有一定的气体选择性,在0.1MPa下对H₂/N₂和CH₄/N₂的分离因子分别为2.25和1.56,气体透过膜孔的扩散由努森机制所控制.等温氮气吸附实验显示,经500℃热处理后氧化硅膜的最可几孔径小于3.34nm,非担载膜的比表面积为919.8m²/g,孔容为0.43mL/g.

Preparation and Structure of Silica Membrane Supported by Hollow Fiber

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.