Copper-promoted heterogeneous Fenton-like oxidation of Rhodamine B over Fe3O4 magnetic nanocatalysts at mild conditions

Abstract

Rhodamine B (RhB) is used in various industries and its effluent must be effectively treated because of its harmful and carcinogenic nature. In this work, ionothermally synthesized Cu-doped Fe₃O₄ magnetic nanoparticles (Cu–Fe₃O₄ MNPs) were found to be a highly efficient heterogeneous Fenton-like catalyst for complete decolorization of the RhB solution with H₂O₂ at pH ~ 7 and 25 °C. The effects of the catalyst loading, initial concentrations of RhB and H₂O₂, co-existing natural organic matter and inorganic salts, reaction temperature, and radical scavengers on the catalytic performance of Cu–Fe₃O₄ were investigated. Monte-Carlo simulations revealed that copper dopants facilitated the activation of H₂O₂ via adopting a terminal end-on adsorption mode and increased collision frequency by bringing the RhB molecules closer to H₂O₂ and the magnetite surface. These theoretical calculations provide new insight into the promotional effect of copper dopants in magnetite at molecular level.