(2020) Journal of Hazardous Materials_An efficient system for electro-Fenton oxidation of pesticide by a reduced graphene oxide-aminopyrazine@3DNi foam gas diffusion electrode

Senthilnathan J., Younis S.A., Kwon E.E., Surenjan A., Kim K.-H., Yoshimura M.

(Elsevier B.V.) Journal of Hazardous Materials ISSN: 3043894 Vol.400 Issue. Article No.123323 DOI: 10.1016/j.jhazmat.2020.123323

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 H2O2 and OH radicals by this electrode was assessed relative to 3DNiF and rGO-AmPyraz@indium tin oxide (ITO) electrodes and with/without a coated Fe3O4 plate. The rGO-AmPyraz@3DNiF electrode showed the maximum production of these radicals at 2.2 mmol h⁻¹ and 410 μmol 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 H2O2 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.

Our sincere thanks to the PCGMR, Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan and Department of Civil Engineering, and Indian Institute of Technology Madras, Chennai, India for the facilities provided for material characterization and applications. KHK acknowledges support provided by the R&D Center for Green Patrol Technologies through the R&D for Global Top Environmental Technologies funded by the Ministry of the Environment (Grant No: 2018001850001) as well as by a grant from the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (Grant No: 2016R1E1A1A01940995).