Electrocatalytic degradation of phenol in acidic and saline wastewater.

The electrocatalytic degradation of low concentration of phenol (100 800mgL(-1)) as a model contaminant for wastewater treatment was studied on modified beta-PbO2 anode. Various affected factors such as current density (7.5-30 mAcm(-2)), reaction temperature (5-60 degrees C), pH (2-6), salinity of the electrolyte (0.5-10 g L(-1) K2SO4), and circulation rate (100-2400 mLmin(-1)) were investigated. Phenol at a concentration level of 100 mg L(-1) could be completely degraded within 30 min under the current density of 7.5 mA cm(-2) with the addition of K2SO4 (1.0 g L(-1)) at pH 5.6 and temperature 60 degrees C. The method showed promising application for treating phenolic wastewater of high salinity and acidity. Analysis of the intermediates of the phenol degradation products indicated good catalytic characteristics of the anode for breaking down the aromatic compounds to organic acids. The overall degradation of phenol was considered a controlled process of mass-transfer. According to the proposed model and Arrhenius's Law, the activation energy was calculated 23.8 kJ mol(-1).