Synthesis of Fe,Mn-Cporous/CF and its application as cathode for electro-Fenton decomposition of organics in water: A comprehensive study

In this study, Fe,Mn-Cporous/CF materials were successfully fabricated by calcination of hydrothermal-produced MIL-100(Fe,Mn)/CF material in N2 gas and applied as an effective cathode in the electro-Fenton (EF) decomposition of Methylene Blue (MB) in water. The characteristics of the materials were analyzed by SEM, XRD, EDX, FTIR, XPS, and TGA-DTG methods. The removal efficiencies of MB, COD, and TOC after 60 min were 98.49, 81.80, and 61.35, respectively, under the conditions: MB concentration of 20 mg/L, Na2SO4 concentration of 50 mM, current density of 13.33 mA.cm−2, pH 3, and temperature of 25 °C. The effects of some anions on the MB removal efficiency were examined and in the order of SO42- < Cl- < NO3- < HCO3- < HPO42-. Radical quenching tests demonstrated the formation and active roles of •OH as the dominant radical. The excellent stability and reusability of the electrode under optimal operating conditions make it great potential for practical applications in the treatment of wastewater containing recalcitrant organics. The EF process was also tested for various water matrices and types of dyes to test its practical application. The mineralization and the ecotoxicity of the treated wastewater were also studied. The mechanism of the EF process using Fe,Mn-Cporous/CF cathode, and the degradation pathway of MB during the EF process were proposed. © 2023 Elsevier Ltd