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

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 FeO magnetic nanoparticles (Cu-FeO MNPs) were found to be a highly efficient heterogeneous Fenton-like catalyst for complete decolorization of the RhB solution with HO at pH ~ 7 and 25 °C. The effects of the catalyst loading, initial concentrations of RhB and HO, co-existing natural organic matter and inorganic salts, reaction temperature, and radical scavengers on the catalytic performance of Cu-FeO were investigated. Monte-Carlo simulations revealed that copper dopants facilitated the activation of HO via adopting a terminal end-on adsorption mode and increased collision frequency by bringing the RhB molecules closer to HO and the magnetite surface. These theoretical calculations provide new insight into the promotional effect of copper dopants in magnetite at molecular level.