Performance Evaluation of PES/Modified-Titanium Oxide Nanofiltration Membrane for Chromium Sulfate Wastewater Treatment

In this study, polyethersulfone (PES)-based nanofiltration (NF) membranes were prepared by introducing synthesized oleic acid-titanium oxide (OA-TiO2) nanoparticles by phase inversion method. Various concentration of OA-TiO2 nanoparticles were used to the membrane fabrication. The OA-TiO2 nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), and X-Ray Diffraction Analysis (XRD). Moreover, the membrane morphology was investigated by FESEM, 3D surface images. The separation performance of membranes were studied by the contact angle, pure water flux (PWF), flux recovery ratio (FRR%), and the rejection of Na2SO4 and CrSO4. The best pure water flux (18.206 L/m2h) was revealed for M2 with 42% increase compared with neat PES membrane at operation pressure 4.5 MPa due to increase membrane hydrophilicity and better dispersion of OA-TiO2 nanoparticles. Furthermore, the best Na2SO4 rejection (81.5%) was obtained to M3 and the highest CrSO4 removal (80.4%) was revealed to M5 at operation pressure 4.5 MPa. The enhancement of salt rejection attributed to Donnan effects and adsorption mechanism. The incorporation of OA-TiO2 nanoparticles into the PES improved the anti-fouling properties and FRR% increased to 83%.