SSZ-13分子筛膜的制备方法及其气体分离

Preparation and Gas Separation Performance of SSZ-13 Zeolite Membranes

SSZ-13分子筛具有CHA构型和3维八元环孔道结构,窗口尺寸约0.38 nm×0.38 nm。相比CH4和N2,SSZ-13分子筛对CO2具有优先吸附选择性,适用于CO2/CH4、CO2/N2等体系的气体分离。SSZ-13分子筛膜的制备方法主要有原位晶化法、二次生长法、微波合成和分子筛转晶法等。高硅SSZ-13分子筛膜的疏水性随着硅铝比的增加而增加,膜层变得更加致密,缺陷减少,气体分离选择性增加。本文梳理了高硅SSZ-13分子筛膜的制备方法和气体分离的机理,分析了支撑体、合成条件、Si/Al比、测试条件和分离体系等因素对高硅SSZ-13分子筛膜气体分离的影响,展望了高硅SSZ-13分子筛膜今后的发展方向。

SSZ-13 zeolite has CHA topology and elliptical cages of large pore volume derived from its low framework density and 3-dimensional eight-membered ring windows(0.38 nm×0.38 nm).In contrast to CH4 and N2,SSZ-13 zeolite preferentially adsorbs CO2,and thus is suitable for CO2/CH4 or CO2/N2 gas separation.SSZ-13 membrane can be prepared by in situ crystallization,secondary growth method,microwave synthesis,and interzeolite conversion synthesis.The hydrophobicity increases as the rise of Si/Al ratio,and the membrane layer becomes more uniform,with less defects,and much more selectivity,which is beneficial for natural gas purification and fuel gas separation.The main processes of preparation of SSZ-13 membranes are reviewed.The mechanism of gas separation of SSZ-13 membrane is summarized.The effects of supports,the composing conditions,Si/Al ratios,test conditions,and the gas mixtures on gas separation performance of SSZ-13 membranes are evaluated in this paper.The further development of high-silica SSZ-13 membrane is forecasted.