Behavior of a Ti/RuO2 anode in concentrated chloride medium for phenol and their chlorinated intermediates electrooxidation

The electrooxidation of phenol and its intermediate compounds in concentrated sodium chloride solutions on a Ti/RuO2 anode was studied with electrochemical techniques allied to UV-vis spectrometry, Gas Chromatography/Mass Spectroscopy (GC/MS) and chemical oxygen demand (COD) analysis. Results have shown that although the increase of chloride ion concentration favors initially the chlorophenols formation, it also favors both the phenol and chlorophenols degradation through an indirect oxidation mechanism. Increasing amounts of chloride ion led to a decrease in the specific energy consumption for both phenol and COD removal from solution. CG/MS analysis indicated that after a 30-min electrolysis in the presence of 20 g L-1 NaCl, with a current density of 10 mA cm(-2), the treated solution contained less than 0.002% of the initial phenol concentration (100 mg L-1). A substantial reduction in the chlorophenols concentration was also achieved under the same electrolysis conditions. (C) 2010 Elsevier B.V. All rights reserved.