Partial degradation of phenol by advanced electrochemical oxidation process.

The partial electrocatalytic degradation of phenol to organic acids has been investigated using an undivided electrolytic reactor with a beta-PbO2 anode containing fluorine resin. It was found that the decrease of benzoquinone (BQ) formed during phenol degradation and the acceleration of the process from phenol to organic acids are possible under an optimized operating condition. A possible pathway for phenol degradation was proposed, and a mathematical model for phenol and BQ evolution was developed. Operating parameters such as initial pH, current density, and temperature of the reaction were found to greatly impact the degradation rate of the phenol and even the pathway. Higher removal rate of phenol and BQ can be achieved at an appropriate temperature and higher current density in acidic medium preferably at pH 4. Under these conditions, phenol would be more likely degraded in the pathway from phenol to organic acids rather than through the BQ. When phenol is completely removed, the toxicity of the wastewater would be lessened suitable for biological process treatment. Accounting for the decrease of instantaneous current efficiency (ICE) during degradation, partial degradation would be highly economical for wastewater treatment, which would be an alternative process in practical application.