Electrochemical Oxidation of Phenolic Compounds from Dilute Aqueous Solutions

The feasibility of electrochemical oxidation of selected organic compounds was evaluated in the laboratory using cyclic voltammetric techniques. A rotating ring disk (Pt) electrode was used. The phenolic compounds of environmental importance were selected for investigation. The results show clearly that phenolic compounds are electrochemically oxidizable, as reflected by the unique characteristics of voltammograms. The anodic current is proportional to the removal rate of organic substances. It also noticed that the aliphatic compounds are found in the products of electrolysis of phenols. There is strong evidence that aromatic ring cleavage is achieved at the electrode surface. Among the phenolic compounds tested, the phenols with the most amount of hydroxy functional group are the easiest to be oxidized; the greater the number of hydroxy group, the larger the anodic current. The other factor, which is also important in affecting the oxidation efficiency, is the pH value in the solution. Under the alkaline condition, the hydroxyl ions are oxidized to form the hydroxyl radicals in the anodic region. Those radicals would react with the neutral molecules and cause the benzene ring to undergo hydrolization.