A fluorinated, defect-free ZIF-8/PDMS mixed matrix membrane for enhancing ethanol pervaporation

A high-quality mixed matrix membrane (MMM) with high flux and separation factor is fostered to enhance ethanol pervaporation. In this study, a fluorinated and defect-free ZIF-8/PDMS membrane was prepared by the covalent bonding among fluoromonomer, ZIF-8 particles and PDMS using a one-pot method. ZIF-8 is first modified with 3-amino-1,2,4-triazole (Atz) to graft –NH2 groups, and then modified with glycidyl methacrylate (GMA). This was achieved by the amine-epoxide addition reaction (named GZIF-8) to facilitate covalent bonding with methacrylate-functionalized PDMS, where the interfacial compatibility ZIF-8 and PDMS is improved. Moreover, 1H,1H,2H,2H-perfluorooctyl methacrylate (13F) as F-monomer is introduced into the membrane formation process by the polymerization of methacrylate groups among 13F, ZIF-8 and PDMS, where a fluorinated structure with high hydrophobicity and low surface energy is formed. The pervaporation performance for a 5 wt% ethanol solution at 60 °C shows that the resulting MMM has a high separation factor of 9.5 and total flux of 1681 g m−2 h−1 under the optimized parameters of 3 wt% GZIF-8 loading and 12 wt% 13F amounts.