Advanced organic molecular sieve membranes for carbon capture: Current status, challenges and prospects

Carbon capture is crucial to reducing anthropogenic carbon emissions and thus mitigating global warming. Owing to the energy-efficient and environmental-benign features, membrane technology holds great potential to achieve highly efficient carbon capture. To realize economically viable membrane technology, developing high-performance membrane materials is of key importance. Recently, organic molecular sieve membranes (OMSMs), not only possessing excellent processability like conventional polymer but also containing high-density, well-defined micropores for molecular differentiation, have attracted increasing research attention. In this review, we discuss recent progress of OMSMs for carbon capture, including the separation of three relevant gas pairs, that is, H₂/CO₂ (pre-combustion capture), O₂/N₂ (oxy-fuel combustion) and CO₂/N₂ (post-combustion capture). Membrane materials including polymers of intrinsic microporosity, thermal-rearranged polymers, covalent organic frameworks, and the emerging hydrogen organic frameworks and porous organic cages, are analyzed. The regulation strategies and stability of micropore structure, and the processability of OMSM materials are summarized. Moreover, we highlight the applications of the OMSMs for the three carbon capture routes. Finally, we conclude with a perspective on the major challenges and the opportunities existing in OMSMs, aiming at identifying the future directions.