In this study, in-situ synthesis of zinc oxide (ZnO) nanoparticles was utilized as an effective approach to prepare poly(vinyl alcohol) (PVA) and poly(vinyl alcohol)-graft-acrylonitrile/2-hydroxyethyl methacrylate (PVA-g-AN/HEMA) membranes with ZnO nanoparticles. The membranes were characterized by using Frourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-Ray diffraction (XRD) and contact angle measurements. Both of the membranes were utilized in separation of acetone/water mixtures via pervaporation technique and the optimum conditions regarding ZnO content within the membranes, acetone content in the feed solution and operating temperature were determined. PVA-g-AN/HEMA-ZnO nanocomposite membranes showed high permeation rate but low separation factor compared to PVA-ZnO nanocomposite membranes. Permeation rate and separation factor values were found to be in the range of 0.028-0.137 and 0.035-0.174 kg m(-2) h(-1), 17.61-325 and 9.4-84.5 depending on the pervaporation conditions for PVA-ZnO and PVA-g-AN/HEMA-ZnO nanocomposite membranes, respectively. (C) 2020 Elsevier B.V. All rights reserved.