膜科学与技术

在大孔陶瓷管载体上引入ZnO连接层诱导合成稳定ZIF-8膜

作者：李绍辉，刘海鸥，张雄福﹡

单位：大连理工大学化工学院，精细化工国家重点实验室，大连 116024

关键词：金属有机骨架膜；ZIF-8膜；膜制备；气体渗透

出版年,卷(期):页码： 2014,34(5):65-72

摘要：

以平均孔径为3µm的大孔α-Al2O3陶瓷管为载体，采用载体表面预先引入一层ZnO作为连接和诱导成膜的策略，合成连续完整且性能稳定的ZIF-8膜. 首先在载体的内表面通过溶剂热生长一层厚度约为5µm的连续多孔ZnO层，起到对载体表面的修饰、连接膜与载体和诱导成膜的多功能作用；然后，甲醇体系溶剂热法在ZnO表面合成得到连续的ZIF-8膜. 考察和优化了ZnO层的活化、ZIF-8合成条件对成膜的影响，运用SEM、XRD和气体渗透等分析手段对所得ZIF-8膜进行了表征. 研究表明，ZnO层的连续性和活化处理是成膜的关键，ZnO层不连续难以形成完整连续ZIF-8膜，不活化ZnO则起不到很好的诱导成膜作用. 最佳条件下获得的ZIF-8膜的H2通量为2.14×10-7mol/(s•m2•Pa)，H2/CO2、H2/N2、H2/CH4的理想分离系数分别为5.18、8.32、8.30. 该膜材料具有明显的筛分效应，且150℃条件下长时间测试稳定性良好.

ZIF-8 membranes were synthesized on macroporous α-Al2O3 tubes of average pore size 3μm as supports by introducing a thin layer of ZnO as linker and induction sites. The preparation procedure involved a two-step process including first the growth of a thin layer of ZnO on the inner surface of the macroporous tube and then the formation of a continuous and dense ZIF-8 membrane. The results showed that a continuous ZnO layer of around 5 μm could be formed on the macroporous tube only in methanol/water synthesis solution. The ZnO layer acted as active sites to induce the uniform nucleation of ZIF-8 nuclei on their surface to guide the growth of a dense ZIF-8 membrane, an inorganic linker between the porous ceramic substrate and the membrane and a modification layer for the surface of the macroporous support. It was crucial to activate the ZnO layer with Hmim solution. Without activation, only some large ZIF-8 crystals could grow on the ZnO surface. The characterization of SEM, XRD and single gas permeation indicated that the quality of the ZnO layer and its activation played key roles in growing a continuous and dense ZIF-8 membrane. For the ZIF-8 membrane achieved under the optimum condition, the H2 permeance was about 2.14×10-7mol/(s•m2•Pa) and the ideal selectivities of H2/CO2, H2/N2 and H2/CH4 were 5.18，8.32，8.30, respectively, which displays good molecular sieving effect. The membrane also demonstrates good stability at 150 ºC.

李绍辉（1987-），硕士，辽宁辽阳人，E-mail:sunny_lsh@126.com 通讯作者：张雄福，教授/博士生导师，E-mail: xfzhang@dlut.edu.cn

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