Zeolite-Geopolymer Composites Membrane Gas Application: Material Design, Gas Transport Mechanism And Research Opportunities

Abstract

Aluminosilicate-based hybrid materials have emerged as a sustainable solution for biogas purification. This mini-review summarizes recent advances in zeolite-geopolymer composite membranes, focusing on material design, gas transport mechanisms, and future research opportunities. Geopolymers offer an environmentally friendly alternative to conventional membranes because of their excellent chemical resistance, long-term stability, and low-temperature processing. Incorporating high-surface-area, ion-exchange zeolites into the geopolymer matrix improves membrane selectivity and gas separation performance. Two main fabrication strategies in-situ hydrothermal crystallization and ex-situ zeolite incorporation are compared, highlighting their influence on crystalline phase formation and membrane microstructure. The review also discusses gas transport mechanisms, emphasizing the roles of molecular sieving and diffusion at the geopolymer-zeolite interface. A key challenge is balancing mechanical strength with functional porosity, as excessive zeolite loading may introduce structural defects. Finally, future research directions are proposed to optimize membrane durability and separation performance for large-scale biogas purification.