MOFs基膜材料的研究现状及其在H_(2)/CH_(4)分离中的应用

Research status and application in H2/CH4 separation of MOFs-based membrane

氢气的生产、分离和储存已经成为世界绿色能源经济的重要组成部分。通过膜分离法从工业副产物中提纯氢气,不但操作简便,且显著降低了分离的能耗,是一种有前景的分离技术。金属有机框架(metal-organic frameworks,MOFs)因具有晶态、有序、明确的多孔结构和较大的比表面积,被认为是理想的气体分离膜材料。本文以MOFs基分离膜为研究对象,对比综述了MOFs膜的常规制备技术,总结了水热/溶剂热法、界面合成法、二次生长法和浇铸法的合成机理及应用。简述了在H_(2)/CH_(4)分离方面MOFs膜的设计原理及应用。针对MOFs膜当前存在的柔性、孔径、晶界结构、稳定性等问题,重点介绍了对制备方法与改良和对薄膜的后修饰策略,以期实现对MOFs膜性能的调控。最后,指出了目前该技术存在的难以大规模生产、分离性能不足的缺点,开发低成本的大规模生产方法同时提高薄膜的分离性能将会是未来MOFs膜实现工业应用的关键。

The production of hydrogen,its separation and storage for use is an important component of the green energy economy of the world.It is a promising separation technology to purify hydrogen from industrial by-products by membrane separation,which is not only easy to operate,but also significantly reduces the energy consumption of separation.Metal-organic frameworks(MOFs)materials possess crystal phase,ordered well-defined porous structure and large surface area,which are considered as an ideal membrane material for gas separation.Based on the literature,the recent progresses in conventional MOFs-based membrane preparation techniques of hydrothermal/solvothermal method,interfacial synthesis method,secondary growth method and casting method are reviewed,including the synthesis mechanism and application.Moreover,the design principle and application of MOFs membrane for H_(2)/CH_(4) separation are also reviewed. Aiming at the problems of the flexibility, pore size, grain boundary structure and stability in order to realize the regulation of MOFs membrane’s performance, the improvement of preparation method and the post-modification strategy for MOFs membrane are introduced. By analyzing and comparing the key technologies, it is pointed that the challenges of MOFs membrane is difficult for large-scale production and the separation performance is insufficient. The effort to promote application of the MOFs membrane in the future is to develop large-scale and low-cost preparation methods and to improve MOFs membrane’s separation performance.