Abstract
Both anodic oxidation and generation of hydrogen peroxide through electroreduction of oxygen may be useful for oxidative degradation of organic compounds. To clarify the effect of electrode reactions of both sides of a bipolar plate on the current efficiency for oxidative degradation of phenol, experiments were conducted by using an undivided bipolar electrolyzer having a vertical stack of perforated graphite electrodes. The Faradaic current If was arranged as a function of the electrode potential difference EB between opposite sides of a bipolar plate. By analyzing the If - EB curves for the electrolyses in solutions containing different reactants, separate currents corresponding to anodic and cathodic reactions were determined. The effect of EB on the COD current efficiency Ce(COD) for the oxidative degradation of phenol could be well explained by the contribution of the currents of phenol oxidation and oxygen reduction to the total current. The value of Ce(COD) in case of sparging oxygen showed a bimodal curve having the maximum values with respect to EB.
