Enhanced CO2-capture performance of polyimide-based mixed matrix membranes by incorporating ZnO@MOF nanocomposites

Abstract

Mixed matrix membranes (MMMs) have received numerous interests as promising membrane configurations for dealing with the energy-intensive gas separation processes. In this study, MMMs were fabricated by incorporating novel ZnO@MOF nanocomposites (ZnO@ZnBDC) into Matrimid (PI) matrix. The physico-chemical properties and microstructures of ZnO@ZnBDC nanocomposites and ZnO@ZnBDC/PI MMMs were characterized. The CO2/CH4 separation performance of MMMs was evaluated and analyzed according to the solution-diffusion mechanism. ZnBDC in the nanocomposites increased CO2 permeability by providing mass transfer pathways with low resistance in the MMMs, while ZnO increased the CO2/CH4 selectivity via high CO2 affinity. Owing to the synergistic effect of the nanocomposites, MMMs with 0.75 wt% ZnO@ZnBDC showed CO2 permeability of 11.5 Barrer and CO2/CH4 selectivity of 39.5, which increased by 67% and 33%, respectively, by comparing with control PI membrane.