Supercritical Ethane Processing of ZIF-8 Membranes towards Pressure-Resistant C₃H₆/C₃H₈ Separation

ZIF-8 membranes have shown great promise in industrial-scale C₃H₆/C₃H₈ separation. Nonetheless, sustainable preparation of pressure-resistant ZIF-8 membranes remains a grand challenge. In this study, we pioneered the use of supercritical ethane (scC₂H₆) as reaction medium for preparing pressure-resistant ZIF-8 membranes. Membrane growth in neutral organic environment was proven to have less disturbance to structure integrity compared with supercritical CO₂ (scCO₂). Gas permeation results indicated that obtained ZIF-8 membrane exhibited an ideal C₃H₆/C₃H₈ selectivity of 172.1 with C₃H₆ permeance of 5.9×10^-9 mol ⋅ m^-2 ⋅ s^-1 ⋅ Pa^-1. Of particular note, the membrane maintained stable C₃H₆/C₃H₈ selectivity of ~150 with C₃H₆ flux of ~1.6×10^-3 mol ⋅ m^-2 ⋅ s^-1 at operation pressure of 6 bar, which was significantly different from ZIF-8 membranes obtained from scCO₂ reaction medium. Through combining with advantages of zero pollutant discharge and full ligand recovery, our protocol holds great promise in sustainable preparation of pressure-resistant ZIF-8 membranes towards practical application in high-purity C₃H₆ production.