Metal–Organic Frameworks Corset with a Thermosetting Polymer for Improved Molecular-Sieving Property of Mixed-Matrix Membranes
Sheng Yang, Yuhan Wang, Peng Lu, Hua Jin, Fusheng Pan, Zixing Shi, Xuesong Jiang, Chen Chen, Zhongyi Jiang, Yanshuo Li
Abstract
Metal–organic frameworks (MOFs) are promising materials for gas separation membranes. However, the framework flexibility affects their molecular-sieving properties. Herein, we restrict the flexibility of zeolitic imidazolate framework-7 (ZIF-7) by controlling its phase transition in mixed-matrix membranes (MMMs), relying on the so-called “space-confinement effect” of a novel thermosetting polymer, poly 2,2′-( p -oxydiphenyl)-5,5′-bibenzimidazole (OPBI) polymer. Compared with the pure OPBI membrane, the optimized membranes containing 30 wt % ZIF-7 with a narrow-pore (np) phase (ZIF-7-II) exhibited a significant improvement in H 2 /CO 2 separation, e.g., the H 2 /CO 2 ideal selectivity increased ∼2.8 times, surpassing the state-of-the-art upper bound of polymeric membranes and exhibited excellent stability at increased pressure and temperature (8 bar, 180 °C).