Poly(vinyl alcohol)/zeolitic imidazolate frameworks (ZIF-8) mixed matrix membranes for pervaporation dehydration of isopropanol

In this study, nanostructured zeolitic imidazolate frameworks (ZIF-8) were successfully synthesized and incorporated into the PVA solution to prepare PVA/ZIF-8 mixed matrix membranes (MMMs). The prepared ZIF-8 nanoparticles and MMMs were characterized by X-ray diffraction (XRD), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM). The prepared MMMs were used to separate mixtures of isopropanol (IPA)/water at 30 °C in the pervaporation (PV) process. The different ZIF-8 loadings in PVA polymer, such as 1, 2.5, 5, 7.5 and 10 wt%, have been tried and ZIF-8 with 5 wt% loading shows the best PV performance. As a result, the 5 wt% ZIF-8 in PVA membrane increases permeation five times without much decrease in separation factor. Separation factor decreases significantly at higher loadings of ZIF-8 due to the agglomeration of nanoparticles in the PVA matrix.