两步干凝胶转化法制备UiO-66膜并用于己烷异构体的高效分离

FABRICATION OF UIO-66 MEMBRANE BY TWO-STEP DRY GELCONVERSION FOR EFFICIENT SEPARATION OFHEXANE ISOMER

己烷异构体是石化行业重要的基础原料,对其进行高效低能耗分离具有重要的战略意义。金属-有机骨架(MOF)材料由于其精准可调的孔道结构和表面功能,在解决挑战性的己烷异构体分离方面备受关注。本文报道了一种以两步干凝胶转化策略制备连续致密UiO-66薄膜的方法。对UiO-66膜的形成过程与微结构的表征结果表明,两次引入锆凝胶是形成致密膜的关键,一方面锆凝胶和晶种的混合相作为前躯体层为膜的初步生长提供了均匀且丰富的多尺度成核位点,另一方面锆凝胶的二次自转化可以密封UiO-66膜的晶间缺陷。渗透汽化试验证实了两步干凝胶转化法制备的UiO-66膜能够优先渗透直链和单支链烷烃而排阻双支链烷烃。

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.