Surface modification of nano-Fe3O4 with EDTA and its use in H2O2 activation for removing organic pollutants

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 degrees 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.