Degradation of Phenol in the Presence of Ammonia by Electrochemical Oxidation in the Chloride System

Abstract

This paper investigated the effect of ammonia-nitrogen to the removal of phenol by electrochemical oxidation in the Chloride System. The electrode of RuO2-Pt/Ti was used as the anode and a Ti plate as the cathode. The results of cyclic voltammetry experiments showed that the RuO2-Pt/Ti anode had no effect of the direct oxidation for both phenol and ammonia- nitrogen, which suggested that the intermediate products of phenol degradation can not be completed on the surface of anode. That makes the electrode more stable and increases the life of electrode. The experiments results showed that the presence of ammonia-nitrogen played an important role in the electrochemical oxidation of phenol. On one hand, the nitrate nitrogen produced by the oxidation of ammonia would be reduced to ammonia by the cathode, which wasted lots of power and hinder the oxidation of phenol. On the other hand, the chloramine produced by the reaction between ammonia-nitrogen and hypochlorite may served as a strong oxidant which can enhance the oxidation of phenol. The degradation of phenol and ammonia was adversely affected by both low and strong alkaline pH. A. Preparation for the Electrode In this research, the RuO2-Pt/Ti electrode (from TOHOTEC Co. Japan) was used as anode to degrade phenol and ammonia. RuO2 is a sort of widely used electrode covering material with strong ability of the evolution of chlorine and higher oxygen evolution potential while high oxygen evolution potential can reduce the losses of electric power and increase the current efficiency. A titanium plate was used as the cathode. B. Cyclic Voltammetry (CV)