Degradation of Orange II in aqueous solution by a novel electro/Fe₃O₄ process

The removal of Orange II in aqueous solution by Fe₃O₄ enhanced anode oxidation (EC/Fe₃O₄ process) was performed in an electrochemical reactor. The process involved the use of a dimensionally stable anode and a stainless steel cathode. Fe₃O₄ was performed as particle electrodes to increase mass transfer coefficient and reduce energy consumption. Various parameters were investigated to optimize the process, including initial pH, Fe₃O₄ dosage and current density. The results indicated that the decolorization of Orange II followed pseudo first-order kinetics. The decolorization was favorable in acidic media than in neutral or alkaline solution, while it increased with the Fe₃O₄ dosage and current density. The total organic carbon (TOC) removal efficiency was 33.2% after 120 min reaction. The X-ray photoelectron spectroscopy was applied to investigate the surface properties of Fe₃O₄ before and after reaction.