Electrochemical study of carboxylic acids with Nb-supported boron doped diamond anode. Part 1: Potentiodynamic measurements and bulk oxidations

•Electrochemical degradation of carboxylic acids on Nb/BDD electrode•Adsorption or non-adsorption interactions of organics towards Nb/BDD surface•FA and OA interactions with surface sites allow a faster oxidation.

The present study was motivated by the reports that promote the use of boron doped diamond (BDD) anode for electrochemical oxidation (EO) of different organic compounds. EO approach on BDD proceeds via electrochemical generation (by water discharge) of hydroxyl radicals and their subsequent reactions. Although the discussion about the degradation of different organic compounds on Si-supported BDD anodes has been already reported; no attempts have been published about the electrochemical degradation of carboxylic acids (acetic, formic and oxalic acids) on Nb/BDD electrode. The interest to elucidate the mechanisms for removing carboxylic acids from water, as a model reaction, contributes to the understanding of more complex reactions involving organic pollutants. In this work, the results clearly demonstrate that organic molecules can be degraded in different way and level by using 0.25 M HClO4 as supporting electrolyte due to the oxidants electrochemically generated as well as the interaction of carboxylic acid with BDD surface by adsorbed/non-adsorbed intermediates. The direct evidence for these processes was found during potentiodynamic measurements and bulk electrolysis of carboxylic acids resulting in different evolution of organic matter removals. The strong oxidants as well as the oxidation potentials were analyzed by spin trapping and voltammetry kinetic studies, respectively.