In-situ synthesis of ZIF-8 gel network in mixed matrix membranes for enhanced CO2/N2 separations

The urgent need for efficient CO₂ capture technologies to mitigate climate change has driven the advancement of membrane-based separation systems. We report a mixed matrix membrane design through the in-situ growth of a ZIF-8 gel network within a Pebax-1657 matrix. By tuning the solvent ratio and concentration of modulator, ZIF-8 gel rather than particles are formed within the polymer, establishing a three-dimensional interconnected MOF network that ensures homogeneous filler dispersion and creates continuous gas transport nanochannels. The optimized membrane achieves a remarkable CO₂ permeability of 183.9 Barrer and a CO₂/N₂ selectivity of 73.3, surpassing the 2008 Robeson upper bound. These values represent 190.4 % and 34.9 % enhancements in permeability and selectivity, compared to the pristine polymer. The membrane also demonstrates robust operational stability and maintains > 95 % of its initial performance over 60 days. This work offers a promising solution to creating continuous channels in CO₂ separation membranes.