An efficient system for electro-Fenton oxidation of pesticide by a reduced graphene oxide-aminopyrazine@3DNi foam gas diffusion electrode

Abstract

A stable rGO-AmPyraz@3DNiF gas diffusion electrode was prepared via modification of 3D nickel foam (3D-NiF) with aminopyrazine functionalized reduced graphene oxide (rGO-AmPyraz) for the electro Fenton (EF) process. The generation capacity of H<inf>2</inf>O<inf>2</inf> and OH radicals by this electrode was assessed relative to 3DNiF and rGO-AmPyraz@indium tin oxide (ITO) electrodes and with/without a coated Fe<inf>3</inf>O<inf>4</inf> plate. The rGO-AmPyraz@3DNiF electrode showed the maximum production of these radicals at 2.2 mmol h?1 and 410 ?mol h?1, respectively (pH 3) with the least leaching of Ni2+ such as < 0.5 mg L?1 even after 5 cycles (e.g., relative to 3DNiF (24 mg L?1). Such control on Ni ion leaching was effective all across the tested pH from 3 to 8.5. Its H<inf>2</inf>O<inf>2</inf> generation capacity was far higher than that of the nanocarbon supported on commercially available ITO conductive glass. The mineralization of dichlorvos (at initial concentration: 50 mg L?1) was confirmed with its complete degradation as the concentrations of the end products (e.g., free Cl?1 (5.36 mg L?1) and phosphate (12.89 mg L?1)) were in good agreement with their stoichiometric concentration in dichlorvos. As such, the proposed system can be recommended as an effective electrode to replace nanocarbon-based product commonly employed for EF processes. © 2020 Elsevier B.V.