Optimization of electrochemical decolorization of certain arylazo pyridone dyes

Abstract

Electrocatalytic decolorization of arylazo pyridone dyes was investigated in the presence of sodium chloride using a DSA Ti/PtOx electrode in dilute sodium hydroxide. The decolorization could be attributed to the indirect oxidation of the investigated dyes by electrogenerated hypochlorite formed from the chloride oxidation. The electrochemical decolorization was investigated for the different sodium hydroxide concentrations in the range from 40 mg dm(-3) to 4 g dm(-3), sodium chloride concentrations in the range from 15 to 40 g dm(-3), currents in the range of 100 to 250 mA and dye concentrations from 5 to 20 mg dm(-3). The optimum electrolysis conditions are suggested. The effect of substituents on the reaction rate was also studied.