Phenol degradation mechanism by electrooxidation using stainless steel electrodes

Abstract

The pathway of phenol degradation by electrochemical oxidation was studied in an aqueous solution using AISI 304 stainless steel electrodes. The increase in pH due to the generation of NaOH in the aqueous solution was found to be critical for the proposed degradation mechanism since the deprotonation of phenol occurs at pH 10. The phenoxy anion produced as a result of deprotonation is resonance stabilized. The Fe⁺³ ions (Lewis catalyst) released from the stainless steel anode and the chlorine gas formed by the electrolysis of sodium chloride are found to be responsible for the chlorination of phenoxy anion ensuing the formation of 2-, 4-, 6-substituted chlorophenols. The mechanism was proposed for elucidating the possible degradation pathway of phenol under the above specified conditions.