Langmuir-Blodgett法制备高H2选择性取向ZSM-5分子筛分离膜

Fabrication of oriented ZSM-5 zeolite membrane with high H_(2) selectivity by Langmuir-Blodgett technique

利用Langmuir-Blodgett(LB)技术首先在多孔氧化铝载体表面有序组装了单层b-轴取向Silicalite-1分子筛晶种层,再采用二次生长法,以溴化六丙双铵(dimer-TPABr)为结构导向剂配制二次生长合成液,在175℃反应48h制备了高度b-轴取向ZSM-5(Si/Al=120)分子筛膜。扫描电镜(SEM)表征显示ZSM-5分子筛膜致密连续且厚度约为2.6μm。X射线衍射(XRD)表征结果显示,膜的b-轴晶体优先取向值高达0.858。气体分离性能测试结果显示,制备的ZSM-5分子筛膜在高温焙烧脱除有机模板剂过程中会产生缺陷。经硅烷试剂四甲氧基硅烷(TMOS)对缺陷修复后,ZSM-5分子筛膜表现出高的H_(2)选择性分离性能,H_(2)/CO_(2)分离因子高达68(T=25℃,p=0.1MPa),对应的H2渗透速率为1.36×10^(-8)mol/(m^(2)·s·Pa)。

Langmuir-Blodgett(LB)technology was used to assemble a highly b-oriented silicalite-1 seed monolayer on porous alumina disk surface.Then,a continuously and highly compact ZSM-5(Si/Al=120)membrane was fabricated after 48h crystallization at 175℃ by using dimer-TPABr as the structure direct agent during the secondary growth procedure.The SEM results showed that the thickness of ZSM-5 zeolite membrane was about 2.6μm.XRD results revealed that the ZSM-5 zeolite membrane was highly boriented and the crystallographic preferred orientation(CPO)indices was 0.858.The gas separation performance test results showed that the prepared ZSM-5 zeolite membrane would produce defects in the calcination process of organic template removal at high temperature.The ZSM-5 membrane showed excellent selective gas separation performance for H_(2) after tetramethoxysilane(TMOS)modification for defects.The separation selectivity of H_(2)/CO_(2) mixture was as high as 68(T=25℃,p=0.1MPa),and the corresponding H2 permeation rate was 1.36×10^(-8)mol/(m^(2)·s·Pa).