Rashidi Fereshteh, Leisen Johannes, Kim Seok-Jhin, Rownaghi Ali A, Jones Christopher W, Nair Sankar
School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
Present address: Pall Corporation, Cortland, NY, 13045, USA.
Angew Chem Int Ed Engl. 2019 Jan 2;58(1):236-239. doi: 10.1002/anie.201811629. Epub 2018 Nov 28.
New membrane-based molecular separation processes are an essential part of the strategy for sustainable chemical production. A large literature on "hybrid" or "mixed-matrix" membranes exists, in which nanoparticles of a higher-performance porous material are dispersed in a polymeric matrix to boost performance. We demonstrate that the hybrid membrane concept can be redefined to achieve much higher performance if the membrane matrix and the dispersed phase are both nanoporous crystalline materials, with no polymeric phase. As the first example of such a system, we find that surface-treated nanoparticles of the zeolite MFI can be incorporated in situ during growth of a polycrystalline membrane of the MOF ZIF-8. The resulting all-nanoporous hybrid membrane shows propylene/propane separation characteristics that exceed known upper-bound performance limits defined for polymers, nanoporous materials, and polymer-based hybrid membranes. This serves as a starting point for a new generation of chemical separation membranes containing interconnected nanoporous crystalline phases.
基于新型膜的分子分离过程是可持续化化学品生产战略的重要组成部分。目前存在大量关于“混合”或“混合基质”膜的文献，其中高性能多孔材料的纳米颗粒分散在聚合物基质中以提高性能。我们证明，如果膜基质和分散相均为无聚合物相的纳米多孔晶体材料，那么混合膜的概念可以被重新定义以实现更高的性能。作为此类系统的首个示例，我们发现，在MOF ZIF-8多晶膜生长过程中，可以原位掺入经表面处理的沸石MFI纳米颗粒。由此得到的全纳米多孔混合膜展现出的丙烯/丙烷分离特性超过了为聚合物、纳米多孔材料及聚合物基混合膜定义的已知上限性能极限。这为新一代包含相互连接的纳米多孔晶相的化学分离膜奠定了基础。
