Mixed-Matrix Membranes Embedded with Ultramicroporous Metal–Organic Framework Nanosheets for Enhanced Propylene/Propane Separation

Mixed-matrix membranes (MMMs) show great promise for C3H6/C3H8 separation by combining polymers and inorganic fillers, but issues such as filler agglomeration and poor compatibility reduce performance. Herein, high-performing CPL-type MOFs/6FDA-DAM MMMs were developed with uniformly dispersed ZU-901 nanosheets achieved through solvent optimization and filler morphology control. At 20 wt % ZU-901 loading, the selectivity reached 49.7 (309% improvement) with a C3H6 permeability of 84.5 Barrer, exceeding the 2020 upper bound and outperforming most MOF-based MMMs. In contrast, MMMs with CPL-1 and CPL-1-NH2 showed lower selectivity due to larger pores and poor interfacial compatibility. This study offers valuable insights into achieving highly selective C3H6/C3H8 separation by precisely regulating the filler dispersion and interfacial compatibility.