Enhanced ceramic membranes filtration by PS pre-Oxidation with CuO assisted FeSO4 catalytic for NOM removal in drinking water treatment

Recently, persulfate oxidation technology has been widely utilized for the degradation of natural organic matter (NOM) in water treatment. This study proposed novel enhanced ceramic membrane filtration system by persulfate (PS) pre-oxidation with CuO and FeSO4 catalytic, which can achieve the high NOM remove performance and low membrane fouling. Firstly, the removal efficiency and mechanism of humic acid (HA) using the CuO/FeSO4/K2S2O8 advanced oxidation system under various operating conditions were investigated. The results indicate that optimal conditions (FeSO4 at 0.016 g/L, CuO at 0.048 g/L, and K2S2O8 at 0.6 g/L) result in substantial removal effects of total organic carbon (TOC, approximately 80 %) and excitation-emission matrix (EEM) spectra by CuO/FeSO4/K2S2O8. Subsequently, with the cycling operation conditions, enhanced ceramic membrane filtration with CuO/FeSO4/K2S2O8 pre-oxidation demonstrates effective removal of HA (approximately 85 %) and significant reduction of membrane fouling (around 60 %), as confirmed by EEM and TOC analysis. Furthermore, during continuous operation, CuO/FeSO4/K2S2O8 pre-oxidation proves to be effective in removing surface water contaminants (approximately 65 %) and mitigating membrane fouling (around 50 %). Finally, through the measurement of Fe2+, Cu2+, and Cu+ concentrations, as well as Field-Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS) characterization of CuO, it becomes evident that CuO exhibits synergistic effects with FeSO4 by adsorbing Fe2+ from the solution and reducing Cu2+ to Cu+. This process generates SO4 center dot-, center dot OH, and center dot O-2(-) radicals within the CuO/FeSO4/K2S2O8 oxidation system. The proposed ceramic membrane filtration system in this study shows great potential in the drinking water treatment for NOM removal.