透醇Silicalite-2沸石膜制备及其疏水改性

Preparation and hydrophobic modification of ethanol perm-selective Silicalite-2 zeolite membrane

Silicalite-2沸石膜以其特殊的直孔道结构和骨架中不含铝而具有强疏水性,成为潜在的优良透醇沸石膜材料.在大孔氧化铝载体上采用二次水热生长法,150℃晶化72h制备出了Silicalite-2沸石膜,并在60℃下对质量分数5%乙醇/95%水溶液进行了渗透蒸发测试,通量和分离因子分别为7.61kg/(m^2·h)和6.7.膜材料疏水改性是提高其醇水分离性能的有效途径.通过在制备的沸石膜表面负载一层二氧化硅颗粒以提高表面粗糙度并进一步利用三甲基氯硅烷进行修饰提高膜的疏水性.修饰后的沸石膜疏水性显著提高,水接触角为127.5°,在60℃下对质量分数5%乙醇/95%水溶液的渗透蒸发通量和分离因子达到3.67kg/(m^2·h)和31.4.

Silicalite-2zeolite membrane has strong hydrophobicity due to the special straight channels and the absence of Al element in the framework,so it can be used as a potential excellent zeolite membrane material.A secondary hydrothermal growth method was used on a macroporous alumina support to prepare the Silicalite-2zeolite membrane by crystallization at 150℃for 72hours.The separation performance of Silicalite-2zeolite membrane was studied for 5%of ethanol/water mixture at 60℃,exhibiting a flux and separation factor of 7.61kg/(m2·h)and 6.7,respectively.The hydrophobic modification of membrane materials is an effective way to improve the separation performance of ethanol/water mixtures.In this paper,a layer of silica particles is loaded on the surface of the zeolite membrane,and further modified with trimethylchlorosilane to enhance its hydrophobicity.The hydrophobicity of the modified zeolite membrane is significantly improved with a water contact angle of 127.5°.Moreover,the modified membrane shows a flux and separation factor of 3.67kg/(m^2·h)and 31.4,respectively for 5%of ethanol/water mixture at 60℃.