AbstractCuprous oxide nanoparticles (Cu2O) were synthesized by electrochemical method and as an add-on toconstruct polyethersulfone (PES) nanofiltration (NF) membranes. Field emission scanning electron microscopy (FESEM),3D surface images, X-ray diffraction (XRD) analysis, and Fourier transform infrared (FTIR) spectroscopy were utilizedto indicate membranes and nanoparticles. Membranes were evaluated by tests of water content, porosity, contact angle,salt rejection, water flux and average pore size measurements. The results show the enhancement of surface hydro-philicity by the addition of Cu2O nanoparticles. The highest unalloyed water flux was obtained by membrane, includ-ing 0.05wt% Cu2O nanoparticles, and the highest rejection was revealed by a membrane containing 2wt% Cu2Onanoparticles. The Na2SO4rejection reached 66.94%, which was significantly higher than the bare PES membrane. Thisperformance may be owing to increased Na2SO4adsorption sites. The heavy metals rejection of CrSO4, Pb(NO3)2, andCu (NO3)2increased 79.38%, 85.08%, and 81% for the M5 membrane, respectively, while it was 45%, 46%, and 49% for bare membrane, respectively. Furthermore, the flux of unalloyed water increased from 9.78L/m·h on the pure PES membrane to 36.78L/m·h on the M1 membrane. The decrease of surface roughness and also the increase of hydro-philic groups improved the antifouling properties of the membranes.
