Synthesis of Mo2C@CeO2@Fe3O4 particles for enhancing three-dimensional heterogeneous electro-Fenton degradation of MIT and HEDP

Mo₂C@Fe₃O₄ and three kinds of MO₂-doped Mo₂C@Fe₃O₄ were successfully fabricated as the Mo₂C@TiO₂@Fe₃O₄, Mo₂C@MoO₂@Fe₃O₄ and Mo₂C@CeO₂@Fe₃O₄ particles for the degradation of 2-methyl-4-isothiazolin-3-one and 1-hydroxy-1,1-diphosphonoethane in a three-dimensional electro-Fenton system. The catalyst particles showed an enhancement for the catalytic activity in the system. Furthermore, the Mo₂C@CeO₂@Fe₃O₄ particles exhibited superior activity for 2-methyl-4-isothiazolin-3-one and 1-hydroxy-1,1-diphosphonoethane degradation compared to the other two particles. Based on the characterization of the synthesized particles, leaching concentration of Fe²⁺, generation of \({H}_{2}{O}_{2}\), \(\bullet OH\), \({O}_{2}^{\bullet -}\), the reasons for the difference in pollutant degradation performance among the three type particles were comprehensively analyzed. At last, some important experimental parameters, such as particles dosage, current density and aeration intensity, which would obviously affect MIT and HEDP degradation performance were studied. Using the Mo₂C@CeO₂@Fe₃O₄ as catalytic particles, optimal 2-methyl-4-isothiazolin-3-one and 1-hydroxy-1,1-diphosphonoethane degradation rates were 97.2% and 73.8% with 0.5 g of particle dosage, 97.22% and 73.75% with 300 mA of current density, and 97.28% and 73.71% with 0.1 L min⁻¹ of aeration intensity.