Surface modification of nano-Fe3O4 with EDTA and its use in H2O2activation for removing organic pollutants

Abstract

The effect of EDTA on the H₂O₂ activation ability of Fe₃O₄ nanoparticles was investigated for removing organic pollutants. Regular Fe₃O₄ nanoparticles were observed to have moderate catalytic activity, which was not suitable for the degradation of various organic pollutants. The addition of EDTA enhanced the activation of H₂O₂ on the surface of Fe₃O₄ nanoparticles, thereby accelerating the formation of reactive oxygen species and increasing the degradation rates of pentachlorophenol, sulfamonomethoxine, and Rhodamine B by 84.4, 48.3, and 17.5 times, respectively, at pH 5.0 and 40 °C. Based on spectroscopic and density functional theory studies, adsorption mechanisms for H₂O₂ and EDTA on the surface of Fe₃O₄ nanoparticles were proposed. It was clarified that the enhancing effect of EDTA was attributed to an appreciable improvement of Fe³⁺/Fe²⁺ recycling on the surface of Fe₃O₄ nanoparticles, and to the simultaneous degradation of EDTA and target pollutants.