Simultaneously promoting CO₂ permeability and selectivity of polyethylene oxide membranes via introducing CO₂-philic KAUST-7

To overcome the challenging trade-off between permeability and selectivity in polymer CO2 separation membranes, CO2-philic metal-organic framework (MOF) KAUST-7 was incorporated within polyethylene oxide (PEO)-type matrices to prepare mixed matrix membranes (MMMs). A cross-scale approach of quantum chemical calculations and molecular dynamics simulations was used to explore the behavior and mechanism of CO2 adsorption on KAUST-7. The strong affinity between KAUST-7 and CO2 enabled a dramatic increase in the CO2 solubility of MMMs. The 2 wt% KAUST-7 loaded MMM exhibited CO2 permeability and CO2/N-2 selectivity of 608 Barrer and 75, respectively, representing 41.7% and 54% improvement compared to the neat membrane, exceeding the 2019 upper bound. Furthermore, long-term separation tests for 100 h demonstrated the stability of these membranes.