两步干凝胶转化法制备Ui()-66膜并用于 己烷异构体的高效分离

Hexane isomer is an important basic chemical raw material in the petrochemical industry, so it is of great strategic significance to separate it efficiently and with low energy consumption. Metal-organic frameworks(MOF) have attracted much attention in solving the challenging problem of hexane isomer separations due to their precisely adjustable pore structure and surface function. A two-step dry gel conversion method for the preparation of continuous dense UiO-66 membranes was reported. The characterization of the formation process and microstructure of UiO-66 membranes were analyzed by combining various characterization techniques. The results showed that the introduction of zirconium gel twice was the key to the formation of dense membranes, on the one hand, the mixed phase of zirconium gel and UiO-66 seed crystal,as precursor layer,provided homogeneous and abundant nucleation sites for the initial growth of the membrane, on the other hand, the second self-transformation of zirconium gel could seal the inter-crystalline defects of the membrane layer. The pervaporation experiment proved that UiO-66 membrane prepared by the two-step dry gel conversion method could permeate straight-chain and mono-branched alkanes preferentially, while repelling di-branched alkanes.