Redefining progress, challenges, and future opportunities of mixed-matrix membranes from an engineering perspective for commercial gas separation applications: A review

Mixed-matrix membranes (MMMs) for gas separations integrate inorganic fillers into a polymer matrix, combining the cost-effective scalability of polymer membranes with the superior performance of expensive inorganic ones. Over the past three decades, the development of MMMs has focused on addressing scientific challenges such as filler agglomeration and poor interfacial interaction, which significantly impact the performance and scalability. Despite breakthroughs in mitigating these issues, translating these achievements into commercially viable solutions has been limited. This review reevaluates the developments, challenges, and prospects of MMMs, emphasizing the engineering perspective in addressing the practical aspects of scale-up and commercialization. It highlights, in particular, fabrication strategies and the importance of engineering approaches in realizing their commercial potential. Furthermore, it discusses the advantages, disadvantages, scalability, and cost implications of both traditional and recent MMM processing methods, outlining the benchmarks required for MMMs to be commercially viable on a large scale. This perspective encourages a shift towards application-driven research to advance the development of MMMs that meet both performance and commercialization criteria.