Degradation of atrazine by electroactivation of persulfate using FeCuO@C modified composite cathode: Synergistic activation mechanism

In sulfate radical-based advanced oxidation processes (SR-AOPs), high-efficiency and perdurable materials have drawn considerable interest for use as cathodes, which can effectively degrade refractory organic contaminants through the synergistic electro-activation and transition metal activation of persulfate (PS). Here, the FeCuO@C modified composite cathode (FeCuO@C/AGF) was synthesized via the solvothermal and thermal treatment method based on the CuFe-MOF-74 structure, and the electro-activation PS process (EC/FeCuO@C/AGF/PS) was developed to effectively remove atrazine (ATZ). The surface morphology, electrochemical characteristics, chemical composition, crystal structure, and electrode surface wettability of FeCuO@C/AGF were investigated. It was found that the proposed EC/FeCuO@C/AGF/PS process can successfully remove 100% of ATZ in 20 min at a low current density (2 mA cm-2) and a low PS concentration (0.4 mM), and PS is successfully activated by combining the electrical and transition metal synergistic activation. The FeCuO@C/AGF cathode exhibits outstanding catalytic functionality over a broad pH range (2-9) and remains stable over five successive cycles. Additionally, the active species involved in the reaction as well as the potential ATZ degradation reaction mechanisms and pathways are discussed. Electrochemical oxidation is a process in which both radicals (SO4·-, ·OH, and O2·-) and non-radical (1O2) participate in the degradation of ATZ. The intermediates of the ATZ degradation process were studied upon the toxicity changing, and the toxicity of the intermediates was found to be reduced during degradation. These results present a novel approach toward the establishment of an effective and reliable electrode in SR-AOPs that can efficiently treat pesticide wastewater.