A mixed matrix membrane for enhanced CO2/N2 separation via aligning hierarchical porous zeolite with a polyethersulfone based comb-like polymer

Abstract Background Mixed matrix membranes (MMM)s for CO2/N2 separation still suffer from interfacial defects. Method To address this, a series of MMMs were prepared using polyethersulfone-g-poly (ethylene glycol) (PES-g-PEG) comb-like copolymer to tune the interfacial interaction with a pillared MFI (PMFI) zeolite nanosheets, which has a hierarchical porous structure to improve permeance. The composite membranes were examined by SEM, EDX and XRD. The dependence of gas permeabilities, diffusion and solubility coefficients of CO2 and N2 were determined by the time-lag method. Results The increase in PMFI zeolite loading led to an increase in the permeability coefficient of CO2, which is mainly caused by the increase in CO2 diffusion coefficient. The CO2/N2 gas separation was optimized at a loading of 20wt% PMFI zeolite, which produces a composite membrane with a CO2 permeability of 66.9 Barrer and an ideal permeability selectivity coefficient of 9.6.