Hydrophobic-functionalized ZIF-8 nanoparticles incorporated PDMS membranes for high-selective separation of propane/nitrogen

It is still a great challenge to prepare high performance mixed matrix membranes (MMMs) because of the difficulty in finely tuning the compatibility between filler and organic phases. In this work, ZIF-8 nanoparticles hydrophobically functionalized by 5, 6-dimethylbenzimidazole (DMBIM) via shell ligand exchange (SLE) reaction were incorporated into polydimethylsiloxane (PDMS) matrix to fabricate defect-free MMMs. Organic-–inorganic interface compatibility was realized because of more abundant organic ligands from DMBIM. The effects of different loadings on membrane microstructure and gas separation performance were investigated systematically. A significantly enhanced C₃H₈/N₂ separation performance with C₃H₈ permeability over 2.10 × 10⁴ Barrer (91 % higher than that of pure PDMS membrane) and C₃H₈/N₂ selectivity of 99.5 (116 % higher than that of pure PDMS membrane) were achieved. Additionally, the as-prepared membrane also exhibited excellent stability during long term operation.