Metal–organic framework-based mixed-matrix membranes for olefin/paraffin separation: from materials innovation to industrial readiness

The separation of olefins from their corresponding paraffins is a critical and energy-intensive process in the petrochemical industry. Conventional cryogenic distillation, although widely used, suffers from high operational costs and environmental impact due to the close physical properties of these light hydrocarbons. In contrast, membrane-based separation, especially using metal–organic framework (MOF)-based mixed-matrix membranes (MMMs) has emerged as a promising alternative, offering energy-efficient and scalable solutions. This review presents a comprehensive overview of recent advancements in MOF–MMMs for olefin/paraffin separation, focusing on the synergistic integration of MOFs as selective fillers and polymers as processable matrices. The unique structural tunability of MOFs through precise pore engineering, open metal sites, and π-affinitive functionalities enable enhanced olefin selectivity via mechanisms such as size exclusion, π-complexation, and kinetic sieving. Coupled with improved polymer–MOF compatibility strategies, MOF–MMMs have demonstrated remarkable performance, often surpassing the Robeson upper bound. Key developments in fabrication techniques, filler functionalization, and thin-film composite architectures are discussed alongside comparative performance data for olefin/paraffin separation. The review also addresses critical challenges that must be overcome for industrial adoption, including scalable MOF synthesis, module fabrication, long-term membrane stability, and tolerance to real-gas contaminants. By bridging the gap between materials innovation and process engineering, MOF–MMMs are poised to play a transformative role in redefining future olefin purification technologies.