离子液体修复的纳米金属有机框架颗粒膜的制备及其H2渗透性能研究

Metal organic frameworks (MOFs), as a highly potential membrane separation material with extraordinarily high surface areas and adjustable pore structure, show promise for H2 separation. However, traditional MOFs membranes show poor permeance, it is highly desired to develop novel MOFs membrane with both high permeance and selectivity. The main target of this project is to develop membranes composed of MOFs nanoparticles with high-performance, ionic liquid is introduced to repair the particle gaps, and then the permeance and selectivity for H2 are studied. In this project, firstly, the membrane is obtained by the bottom-up accumulation of MOFs nanoparticles. The influences of prefunctionalization of the substrate and monodispersity of the nanoparticles on the membrane quality are investigated to prepare a high quality membrane composed of MOFs nanoparticles. Secondly, ionic liquid is introduced to the gaps of nanoparticles. The effect of the interface between ionic liquid and MOFs and ionic liquid loadings on the microstructure and separation performance of the membrane are investigated. Accordingly, the dependence of microstructure and separation performance is clarified. As a result, defect-free ionic liquid repaired membranes composed of MOFs nanoparticles with high separation performance is obtained, which provides a novel route for the efficient separation for H2.

金属有机框架(MOFs)具有表面积大、孔道结构可设计和调控等优点，被认为极具潜力的膜分离材料，可用于H2的分离。然而传统的MOFs膜的渗透通量较低，在保持MOFs膜原有选择性的基础上提高其渗透通量是一个亟待解决的关键难题，本项目重点开发高性能的纳米MOFs颗粒膜，并引入离子液体修复颗粒间隙，考察其渗透通量和对H2的选择性。首先，通过MOFs纳米颗粒自下而上堆积成膜，考察基底预功能化与纳米颗粒单分散性对膜质量的影响，从而制得高质量的纳米MOFs颗粒膜；其次，在颗粒间隙引入离子液体，考察离子液体和MOFs的界面效应及离子液体负载量对膜的微结构及分离性能的影响，进而揭示膜的微结构与分离性能之间的依赖关系，从而获得无缺陷、高分离性能的离子液体修复的纳米MOFs颗粒膜，为实现H2的高效分离提供新的途径。

传统的MOFs膜的渗透通量较低，为了在保持MOFs膜原有选择性的基础上提高其渗透通量，本项目采用胶体晶法和原位生长法两种制膜方法，改变制膜条件制备系列纳米ZIF-8颗粒膜，针对ZIF-8颗粒堆积过程中存在的缺陷，进一步引入两种亲疏水性不同的离子液体进行修复，并调变离子液体的负载量，制备了一系列离子液体修复的纳米ZIF-8颗粒膜，对两种离子液体的存在形式及与MOFs的相互作用力进行了考察，借助FTIR、XRD、SEM等表征手段对膜的微结构进行了表征，并且完成了复合膜在H2/CO2混合气氛条件下的分离性能的测试工作。制备的离子液体修复的纳米ZIF-8颗粒膜在H2/CO2混合气氛下选择性达53、渗透性达1.5×10-6 mol m-2 s-1 Pa-1,并能稳定运行120h，为实现H2的高效分离提供了新的途径。

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