A drying-free, water-based process for fabricating mixed-matrix membranes with outstanding pervaporation performance
Despite much progress in the development of mixedmatrix membranes (MMMs) for many advanced applications,the synthesis of MMMs without particle agglomeration orphase separation at high nanofiller loadings is still challenging.In this work, we synthesized nanoporous zeolitic imidazoleframework (ZIF-8) nanoparticles with a particle size of 60 nmand a pore size of 0.34 nm in water and directly added theminto an aqueous solution of the organic polymer poly(vinylalcohol) (PVA) without an intermediate drying process. Thisapproach led to a high-quality PVA/ZIF-8 MMM withenhanced performance in ethanol dehydration by pervapora-tion. The permeability of this MMM is three times higher thanthat of pristine PVA, and the separation factor is nearly ninetimes larger than that of pristine PVA. The significantlyimproved separation performance was attributed to theincrease in the fractional free volume in the membranes.