Mechanism of Fenton catalytic degradation of Rhodamine B induced by microwave and Fe3O4

The Fenton method is an effective technology for the removal of organic materials from wastewater. In this work, an induced catalyst Fe3O4 was synthesized by a hydrothermal method, and the modulation of the chemical composition of Fe3O4 crystals was achieved under the microwave shock method with the same effect as that of calcination treatment. Fe3O4 catalyst for the removal of the dye Rhodamine B (RhB) from polluted wastewater under microwave (MW), H2O2 system. The results showed that Fe3O4 nanomicrospheres prepared by microwave shock exhibited superior catalytic activity under the conditions of 500 W, 0.4 mol/L H2O2 and10 mg/L RhB, and the removal rate of RhB reached 98.5% after 10 min. The Fe3O4 catalysts also exhibited good stability and degradation efficiency. Electron paramagnetic resonance experiments confirmed that ·OH plays a major role in the rapid degradation of RhB. Under microwave action, the catalyst produces electron-hole pairs, in which the holes react with OH− produced by water ionisation to form ·OH, and the microwave-treated Fe3O4 produces more active species. Fe3+ and Fe2+ serve as microwave catalytic activity centers and Fenton catalytic activity centers, respectively. This research demonstrates that optimizing the Fe2+/Fe3+ ratio significantly enhances the degradation efficiency of RhB. This study presents novel views regarding the mechanism of microwave synergistic catalyst-induced Fenton.