Cuprous oxide (Cu2O) nanoparticles in nanofiltration membrane with enhanced separation performance and anti-fouling properties

Cuprous oxide nanoparticles (Cu 2 O) were synthesized by electrochemical method and as an add-on to construct 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 utilized to 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 hydrophilicity by the addition of Cu 2 O nanoparticles. The highest unalloyed water flux was obtained by membrane, including 0.05 wt% Cu 2 O nanoparticles, and the highest rejection was revealed by a membrane containing 2 wt% Cu 2 O nanoparticles. The Na 2 SO 4 rejection reached 66.94%, which was significantly higher than the bare PES membrane. This performance may be owing to increased Na 2 SO 4 adsorption sites. The heavy metals rejection of CrSO 4 , Pb(NO 3 ) 2 , and Cu (NO 3 ) 2 increased 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 9.78 L/m 2 ·h on the pure PES membrane to 36.78 L/m 2 ·h on the M1 membrane. The decrease of surface roughness and also the increase of hydrophilic groups improved the antifouling properties of the membranes.