Phenolate-based MOF incorporated polyimide membranes with simultaneously enhanced CO2/CH4 separation and anti-plasticization performance

Efficient gas separation is essential for sustainable energy generation and industrial applications; however, membrane materials often encounter an intrinsic trade-off between permeability and selectivity. In this work, we overcome this limitation by incorporating phenolate-based metal-organic frameworks (termed as SU-102) into polyimides (6FDA-Durene) via a physical blending method. Attributable to the strong CO 2 affinity, significant porosity, and distinctive pore size of SU-102, the resulting mixed matrix membranes (MMMs) demonstrate a synergistic enhancement in both CO 2 permeability and selectivity. Specifically, MMMs with 30 wt% SU-102 amounts achieved a CO 2 /CH 4 selectivity of 33.6 and a CO 2 permeability of 1572.3 Barrer, representing increases by 1.8 and 2.2 times, respectively, compared to the pristine 6FDA-Durene membranes. Furthermore, the MMMs exhibited remarkable long-term stability over 72 h of continuous operation. Importantly, hydrogen-bonding interactions between the carboxyl and hydroxyl groups on SU-102 and the imide groups on 6FDA-Durene significantly enhanced the plasticization resistance of the MMMs, which withstood CO 2 pressures up to 12 bar. This work provides a feasible strategy for the design of high-performance gas separation membranes for practical applications.