Recent Advances in the Development of Metal–Organic Frameworks for Propylene and Propane Separation

Separation of propylene (C 3 H 6 ) and propane (C 3 H 8 ) is a vital step for the manufacture of high-purity C 3 H 6 as an important energy source and critical raw material in the petrochemical industry. Due to their similar sizes and properties, the separation of C 3 H 6 and C 3 H 6 is challenging and currently relies on energy-intensive cryogenic distillation. Metal–organic framework (MOF)-assisted adsorptive separation and membrane-based separation are revolutionary energy-saving technologies that can enable efficient gas purification under mild conditions. This review presents the current progress in C 3 H 6 /C 3 H 8 separation achieved with MOFs and MOF-based membranes. The different separation mechanisms (including equilibrium separation, kinetic separation, gate-opening effect, molecular sieving, and combination of them) along with the materials design principles that contribute to benchmark C 3 H 6 /C 3 H 8 separation are discussed. Diverse creative strategies for the fabrication of high-quality MOF membranes (both continuous membranes and mixed-matrix membranes) to surpass the tradeoff between selectivity and gas permeability are summarized. Lastly, this review also outlines the major challenges and opportunities of MOFs to be used for practical C 3 H 6 /C 3 H 8 separation.