Electro-Fenton Process Catalyzed By Fe₃O₄Magnetic Nanoparticles For Degradation Of Simulated Textile Wastewaters

magnetic nanoparticles (MNPs) were employed for electro-Fenton (Fe3O4-electro-Fenton) degradation of C.I. Reactive Blue19(RB19) in an undivided electrochemical reactor with an activated carbon fiber felt cathode and a platinum anode. On the basis of physicochemical characterization of the Fe3O4MNPs as well as quantitative measurements of iron leaching and H2O2generation, it is concluded that the Fe3O4MNPs facilitated the decomposition of H2O2to generate hydroxyl radicals (·OH). Moreover, the cathodic electro-Fenton facilitated electro-regeneration of ferrous ion and maintained continuous supply of H2O2. The effect of several operational parameters such as pH, current density, amount of added Fe3O4MNPs, initial RB19concentration, and temperature on the removal of total organic carbon was investigated. It was found that the Fe3O4-electro-Fenton degradation of RB19followed two-stage first-order kinetics with an induction period and a rapid degradation stage. Mineralization of RB19proceeded rapidly only at pH3.0. Increasing the current density and the dosage of Fe3O4MNPs enhanced the rate of RB19degradation. However, higher current densities and Fe3O4dosages inhibited the reaction. The rate of RB19degradation decreased with the increase in initial RB19concentration and increased with the increase in temperature. The removal efficiency of total organic carbon reached87.0%after120min of electrolysis at an initial pH of3.0, current density of3.0mA/cm2,1.0g/L concentration of added Fe3O4MNPs,100mg/L initial dye concentration, and35℃temperature. On the basis of the analytical results for the intermediate products and the assumption that·OH radicals are the major reactive species, we propose a possible pathway of RB19degradation during the cathodic electro-Fenton process using Fe3O4MNPs as iron source.