有序介孔氧化硅膜的制备及结构研究

Study on Structure and Preparation of Ordered Mesoporous Silica Membrane

本文介绍了在α-Al2O3中空纤维载体上制备担载有序氧化硅膜的方法。应用LXRD、HRTEM、TG-DTA、SEM、氮气吸附等测试手段对膜的结构、形貌进行了表征。LXRD和HRTEM结果显示所制备的非担载膜具有高度有序的二维六方结构。SEM分析发现担载膜表面完整、无缺陷。气体渗透实验表明中空纤维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2.80和1.65,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:500℃热处理后非担载膜的比表面积为548.84m2·g-1,孔容为0.57mL·g-1。

The ordered silica membranes supported by a-alumina hollow fibers was prepared from copolymer plutonic P123 and TEOS. The structure, appearance of silica membranes were characterized by low angle X-ray diffraction （LXRD）, high-resolution transmission electron microscopy （HRTEM）, thermogravimetric analysis （TGA）, differential thermal analysis （DTA）, scanning electron microscopy （SEM） and nitrogen adsorption isotherm measurement. The results of LXRD and HRTEM show that the obtained membranes are of highly ordered hexagonal structure. SEM images indicate that the membranes supported by a-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 2.80 and 1.65 at 0.1 MPa, respectively. It is showed that the gas diffusion through the membrane is governed by Knudsen diffusion mechanism. Nitrogen adsorption isotherm measurement indicate that pore volume and specific surface area of an unsupported membrane after calcination at 500 ℃ is 0.57 mL·g^-1 and 548.84 m^2·g^-1, respectively.