Efficient degradation of p-arsanilic acid with released arsenic removal by magnetic CeO2–Fe3O4 nanoparticles through photo-oxidation and adsorption

Abstract For the first time, a bifunctional CeO2–Fe3O4 material was synthesized and employed for the photocatalytic degradation of p-arsanilic acid (p-ASA) under UV light irradiation and simultaneous thorough removal of the released inorganic arsenic by adsorption from solution. The effects of major factors, including the initial pH, concentration of chloride ion, ammonia nitrogen and humic acid, on the p-ASA degradation were investigated. Under various water quality conditions, an excellent removal of p-ASA could always achieved in the CeO2–Fe3O4 photocatalytic process, and p-ASA could be completely converted to As(V) within 28 min. Simultaneously, the released As(V) could be adsorbed onto the CeO2–Fe3O4 nanoparticles surface with high efficiency above 98% at the initial pH range of 4–7. The p-ASA degradation efficiency significantly decreased in the presence of Cl− and humic acid by scavenging ·HO, while NH4+ had insignificant effect on the degradation of p-ASA. Based on the UV-vis, FTIR, XPS analysis and the major degradation products detected, the mechanism of the p-ASA photocatalytic degradation and the released As(V) adsorption by CeO2–Fe3O4 nanoparticles were proposed. Combined with the photocatalytic property and high adsorption capacity of As(V), the synthesized magnetic CeO2–Fe3O4 nanoparticles have significant potential applications for controlling the risk of p-ASA in aquatic environment.