Custom Formulation of Multicomponent Mixed-Matrix Membranes for Efficient Post-combustion Carbon Capture

Mixed-matrix membranes have great potential for post-combustion carbon capture. To make membrane-based carbon capture economically viable, new formulations with high selectivity and CO2 permeance must be identified. We demonstrate here the ability to break the permeability-selectivity trade-off by using multicomponent mixed-matrix membranes (McMMMs) with two, three, or four components. Each of these components has a specific function and is designed for compatibility and high separation performance. A highly permeable polymer of intrinsic microporosity, PIM-1, and a CO2-selective polyphosphazene polymer, MEEP80, are chosen as polymer matrices. Chemical interaction between MOF nanoparticles and polymers is a key factor for optimizing the MOF-polymer interfacial compatibility. The systematic study of the impact of MOF pore size and the binding site is investigated to produce 10 different composite membranes. The permeability-selectivity values surpass the Robeson upper bound, while the predicted cost of carbon capture is reduced, which suggests the potential of these membranes for practical CO2 separations.