Sustainable Fe3+ reduction by Fe3O4@tourmaline in Fenton-like system

Abstract

To address the issue of low Fe3+ reduction efficiency in the traditional Fenton system, a Fe3O4@tourmaline (Tml) catalyst was developed. For the first time, we investigated the reduction ability of Fe3+ and the source of electrons for Fe3+ reduction in the Fe3O4@Tml Fenton-like system. Results showed that the magnetic catalyst could regenerate 26.17 ± 0.57 μM Fe2+ after stirring at 300 rpm for 60 min. The density functional theory (DFT) calculations showed that Fe3+ tends to get electrons from OH– in water rather than directly from Tml, with a free energy change of −2.954 eV. The Fe3O4@Tml Fenton-like system could remove 96.66 ± 0.01% of sulfathiazole (STZ) after 60 min. In addition, the mechanism of STZ removal suggested that surface ·OH and free ·OH worked together to treat STZ. This study provides a novel Fenton-like catalyst for efficient degradation of STZ and presents the theoretical basis for Fe3+ reduction.