Complementary Mechanism Model for the Electrochemical Mineralization

Gustavo      Rodrigues de Oliveira; Cynthia      Kerzia Costa de Araujo; Carlos      Alberto Martinez-Huitle; Djalma      Ribeiro da Silva

doi:10.2174/138527212803251730

Abstract

Comninellis and his research group have elucidated a theoretical model that permits us to predict the chemical oxygen demand (COD) and instantaneous current efficiency (ICE), during the electrochemical oxidation of organic pollutants on a synthetic boron-doped diamond thin film electrodes (BDD) in a batch recirculation system under galvanostatic conditions. Several studies highlight the good correlation between theoretical predictions and empirical data, but it was noted that some data, from some experiments, were not in agreement with the theoretical model, since it achieved efficiencies above 100%. Recently, few studies have reported phenomena that occur in electrocatalytic systems which were not deducted in the first models. Thus, we emphasize that the mineralization of organic compounds on BDD electrodes involves not only hydroxyl radicals but also the molecular oxygen present in air, in saturated aqueous solutions or strong oxidants generated from simultaneous reactions. Therefore, this highlights summarizes the results reported by other electrochemists until nowadays to understand the electrochemical oxidation mechanisms.

Keywords: Dissolved oxygen, Hydroxyl radicals, Complementary mechanism model, Strong oxidant species, electrochemical oxidation, galvanostatic, organic pollutants, anode, hydroxyl radicals, biodegradable