ELECTROCATALYTIC DEGRADATION OF PHENOL IN ACIDIC AND SALINE WASTEWATER

ABSTRACT

The electrocatalytic degradation of low concentration of phenol (100–800 mg L⁻¹) as a model contaminant for wastewater treatment was studied on modified β-PbO₂ anode. Various affected factors such as current density (7.5–30 mA cm⁻²), reaction temperature (5–60°C), pH (2–6), salinity of the electrolyte (0.5–10 g L⁻¹ K₂SO₄), and circulation rate (100–2400 mL min⁻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°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.

Keywords:

• Electrocatalysis
• Phenol
• Anodic oxidation
• Wastewater treatment

ACKNOWLEDGEMENTS

This work was sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (98679) and Zhejiang Provincial Natural Science Foundation of China (200043).