Electrochemical mineralization of chlorophenol by ruthenium oxide coated titanium electrode

Electrochemical oxidation of 4-chlorophenol (CP) was investigated (in terms of chemical oxygen demand (COD) and CP removal efficiencies) by using a dimensionally stable anode (DSA) namely ruthenium oxide coated titanium (Ti/RuO 2 ) electrode. Effect of process conditions such as current density ( j ), electrolyte concentration ( m ), initial pH (pH o ), time ( t ) and initial CP concentration ( C o ) has been studied. Current efficiency (CE) and specific energy consumption (SEC) were also measured. Gas chromatograph-mass spectrometry (GC/MS) analysis was used to understand the CP mineralization mechanism which has been established on the basis of intermediates identified such as benzoquinone, hydroquinone and organic acids. Reaction kinetics was expressed by pseudo-first order kinetic model. Maximum COD removal efficiency of 96.7% and CP removal efficiency of 97.2%, respectively, was observed at j = 222.22 A/m 2 , t = 180 min, pH o = 5.2 and m = 400 mg/l with SEC = 655 kWh/kg COD. Operating cost based on the studies performed on laboratory scale EC reactor has been calculated and compared with those reported for other pollutants degradation.