Rational Formulation Design of Multicomponent Membranes for Carbon Dioxide Separation

The discovery of a membrane that can effectively remove carbon dioxide from coal-burning power plant emissions would help lower carbon dioxide emissions worldwide. To make membrane-based carbon capture economically viable, new formulations must be identified with high selectivity and high CO₂ permeance. We demonstrated herein the ability to break the permeability/selectivity trade-off by using multicomponent mixed-matrix membranes (McMMMs) with two, three or four components wherein each constituent has a specific function and have been designed for compatibility and high gas separation performance. The chemical interaction between the metal-organic framework (MOF) nanoparticles and the polymers is the key factor for optimizing the MOF-polymer interfacial compatibility. Compared with the neat polymer material, the CO₂ permeability and CO₂/N₂ selectivity were significantly enhanced, while the predicted cost of carbon capture was reduced. The permeability/selectivity values surpass the Robeson upper bound and suggest the potential of these membranes for practical CO₂ separations.