Tuning the Polymer–Zeolite Interface in Mixed Matrix Membranes for Enhanced CO₂ Separation

Background: Mixed matrix membranes (MMMs) offer promising potential for efficient CO₂ separation owing to their ability to integrate the advantages of polymers and inorganic fillers. However, the polymer–zeolite interface often presents challenges such as filler agglomeration and non-ideal morphologies that limit membrane performance. Methods: This review explores strategies for tuning the polymer–zeolite interface through surface functionalization of zeolites, compatibility modification in the polymer matrix, and fabrication techniques. Emphasis is placed on membrane morphology, interface bonding, and their correlation with gas separation efficiency. Results: Functionalized zeolites were found to enhance dispersion within the polymer matrix and form stronger interfacial adhesion, leading to improved CO₂ permeability and selectivity. Several studies reported surpassing Robeson’s upper bound, indicating performance gains through tailored interfaces. Conclusions: Tailoring the polymer–zeolite interface is critical to achieving scalable, high-performance MMMs for CO₂ capture. This review identifies current progress, limitations, and future directions to facilitate industrial deployment of MMM technologies.