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

Separation of propylene (C3H6) and propane (C3H8) is a vital step for the manufacture of high-purity C3H6 as an important energy source and critical raw material in the petrochemical industry. Due to their similar sizes and properties, the separation of C3H6 and C3H6 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 C3H6/C3H8 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 C3H6/C3H8 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 C3H6/C3H8 separation.