Challenges and recent advances in MOF-polymer composite membranes for gas separation

Membrane technology has attracted tremendous attention in the field of gas separation due to its low cost and energy consumption. Polymer membranes are used in some industrial-scale gas separation processes, however, they often suffer a trade-off between permeability and selectivity. To overcome this limitation, porous materials with molecular sieve properties have been combined with polymers to give membranes with enhanced gas separation performance. Metal-organic frameworks (MOFs) are nanoporous materials possessing ultrahigh porosity, large surface area, structural diversity and rich functionalities, which make them promising candidates for gas separation. This review primarily focuses on the fabrication methods of MOF-polymer composite membranes including MOF-based mixed-matrix membranes (MMMs) and polymer supported MOF membranes. Recent progress in MOF membrane fabrication, incorporating the challenges and difficulties faced, are presented. Furthermore, corresponding solutions and strategies are given in detail to offer instructions to fabricate membranes with ideal morphology and performance.