Electro-Fenton-like reactions of transition metal ions with electrogenerated hydrogen peroxide

We evaluated and compared the hydroxyl radical-generating ability of chromium, iron, cobalt, nickel, copper, lanthanum, and cerium ions when reacted with electrogenerated hydrogen peroxide by usage the voltammetry. There was reproduced an electro-Fenton-like reaction in electrochemical cell when metal salt added. The nature of metal ions determined the appearance and increasing of current of hydroxyl radicals cathodic reduction due to individual rate of the redox cycling of metal ions with ongoing cathodic regeneration of Fenton-active metal ions oxidation state. The approximated current magnitude growth in relation to metal ions concentration was calculated for each tested metal. It expressed in μA·ml·μmol−1 and is equal to HO•-generating ability of metal ions. Results are usable for improvement of advanced oxidation processes (AOPs) through enhancement of exploitation of electro-Fenton-like processes with selecting metals that are more active. Besides, in accordance with concept of metal-induced hydroxyl radical stress in biological systems, the hydroxyl radical-generating ability of metal ions is equal to their pro-oxidant capacity