Supercritical Ethane Processing of ZIF-8 Membranes towards Pressure-Resistant CH/CH Separation.

ZIF-8 membranes have shown great promise in industrial-scale CH/CH separation. Nonetheless, sustainable preparation of pressure-resistant ZIF-8 membranes remains a grand challenge. In this study, we pioneered the use of supercritical ethane (scCH) 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 CO (scCO). Gas permeation results indicated that obtained ZIF-8 membrane exhibited an ideal CH/CH selectivity of 172.1 with CH permeance of 5.9×10 mol ⋅ m ⋅ s ⋅ Pa. Of particular note, the membrane maintained stable CH/CH selectivity of ~150 with CH flux of ~1.6×10 mol ⋅ m ⋅ s at operation pressure of 6 bar, which was significantly different from ZIF-8 membranes obtained from scCO 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 CH production.