Ternary cross-linked PVA-APTES-ZIF-90 membrane for enhanced ethanol dehydration performance

To eliminate the interfacial defects between polymeric matrix and inorganic fillers in hybrid membranes, various strategies have been proposed by modifying membrane materials or optimizing membrane formation process. In this work, a ternary cross-linked PVA-APTES-ZIF-90 (PVA, poly(vinyl alcohol); APTES, 3-aminopropyltriethoxysilane; ZIF-90, zeolitic imidazolate framework-90) membrane was developed to eliminate interfacial defects between PVA and ZIF-90 for enhanced ethanol dehydration performance, where APTES served as a covalently linked bridge to cross-link PVA and ZIF-90 simultaneously. The morphologies and physicochemical properties of the resultant membranes were characterized by various characterization techniques. Moreover, we also explored the effects of [ZIF-90]/[APTES] mole ratio and [ZIF-90]/[APTES] loading on the separation performance of the trinity membranes. The results indicated that ZIF-90 particles showed better dispersion and compatibility in PVA-APTES-ZIF-90 trinity membranes than in PVA/ZIF-90 hybrid membrane, attributed to the ternary cross-linking among PVA, APTES, and ZIF-90. Compared with pristine PVA membrane, PVA-APTES-ZIF-90 trinity membranes showed stronger anti-swelling and mechanical properties, as well as more excellent separation performance, which resulted from the incorporation of cross-linker APTES and ZIF-90 particles. The separation factor of the optimal PVA-APTES-ZIF-90 trinity membrane was improved by 215.4%, up to 552, accompanied by a total flux of 82 g/m 2 h. Ternary cross-linking among cross-linker, inorganic filler, and polymeric chain is therefore believed to be a feasible strategy in preparing polymeric-based hybrid membranes with high separation performance. Graphical abstract Summary: A novel ternary cross-linked hybrid membrane with APTES as co-cross-linkers of ZIF-90 and PVA for efficient ethanol dehydration