Mixed matrix membranes for CO₂ separations by incorporating microporous polymer framework fillers with amine-rich nanochannels

Membrane-based separation processes can improve separation efficiency and reduce the environmental hazards and energy costs of traditional separation processes. Mixed matrix membranes (MMMs) with broad development prospects are frequently restricted by interfacial incompatibility and the blockage of gas transport channels in the filler matrix. Here, we report a new type of high-valence metal-induced microporous polymer (HMMP-1) filler, with a high density of free amine groups, and having excellent alkaline stability. The HMMP-1 nanoparticles were incorporated into polyvinylamine (PVAm) to prepare facilitated transport mixed matrix membranes (MMMs). The resulting HMMP-1 based MMMs maintain their pore aperture structure, which is mainly due to the excellent compatibility between the polymer component in the HMMP-1 and PVAm. Amine-rich nanochannels with appropriate pore size allow rapid CO₂ transport through the filler pores by preferential adsorption monomolecular surface diffusion, leading to high CO₂ permeance and excellent separation performance for CO₂/CH₄, CO₂/N₂ and CO₂/H₂ compared with many other reported membranes. A techno-economic evaluation suggests that the MMM is feasible for carbon capture from post-combustion flue gas.