Co/Zn Bimetallic <scp>MOF</scp> ‐Embedded Pebax Mixed Matrix Membranes for Enhanced <scp>CO</scp> ₂ Separation

ABSTRACT In the present investigation, bi‐metallic zeolitic imidazolate frameworks (BM‐ZIF), consisting of 75% Co 2+ and 25% Zn 2+ ions, were synthesized at ambient temperature in an aqueous environment. The BET surface area, along with the CO 2 , N 2 , and CH 4 uptake capabilities of BM‐ZIF, was systematically assessed. Membranes based on Pebax‐1657 were prepared by incorporating BM‐ZIF particles into the polymer matrix, with filler content ranging from 5 to 25 wt% relative to the polymer. The dispersion of the inorganic filler within the membrane matrix, as well as the structural characteristics, physicochemical interfaces, and filler‐polymer interactions, were characterized utilizing FESEM, FTIR, XRD, and DSC techniques. FESEM analysis substantiated the uniform dispersion of the filler throughout the membrane matrix. DSC results showed that crystallinity decreased progressively as the filler loading increased. The synthesized MMMs demonstrated enhanced gas adsorption characteristics relative to the Pebax membrane. Performance of the MMMs was assessed using a custom‐designed experimental setup designed to test both pure gases and binary gas mixtures. For an optimal filler loading of 20 wt% BM‐ZIF, a remarkable 122% increase in CO 2 permeability, alongside 59% and 50% enhancements in CO 2 /N 2 and CO 2 /CH 4 selectivity, respectively, was achieved compared to the unmodified Pebax. In the case of a binary gas mixture, the membrane exhibited a CO 2 permeability of 39.51 Barrer and CO 2 /CH 4 separation factor of approximately 18.8. These findings elucidate the capability of bi‐metallic ZIF fillers to augment the gas separation properties of MMMs, thereby presenting substantial advancements for applications in energy and environmental sectors.