Electrochemically induced mineralization of organics by molecular oxygen on boron-doped diamond electrode

The complete mineralization of organic pollutants present in wastewater is usually achieved via thermally activated oxygen/air. This process occurs at high temperatures and pressures (300 °C, 200 atm) and often gives small amount of acetic acid as a final product. In this work, we demonstrate using acetic acid as a model compound that organic molecules can be activated electrochemically such that they react at room temperature with oxygen, resulting in mineralization of even acetic acid present in 1 M HClO4 supporting electrolyte. This electrochemically induced activation occurs during anodic polarization of boron-doped diamond electrodes (BDD) in air/oxygen-saturated solutions. The direct evidence for this process was found during electro-oxidation of acetic acid saturated with isotopically labelled 18O2 resulting in evolution of C18O2 and C16O18O. We suggest that the mechanism of activation on BDD is initiated by hydroxyl radicals formed on the electrode surface.