Degradation of cationic red X-GRL by electrochemical oxidation on modified PbO2 electrode

This work investigated the degradation of an azo dye, cationic red X-GRL, by electrochemical oxidation on a novel PbO2 anode modified by fluorine resin. The influences of treatment time, electrolyte concentration, current density, temperature and initial dye concentration on the color and COD removal were critically examined. This process showed a high current efficiency and competitive energy consumption for effective treatment of dye wastewater containing a certain salt content. In the investigated electrolyte concentrations, high salt content exhibited insignificant promotion on the color and COD removal but favored the decrease of energy consumption. During treatment, the current efficiency decreased but the energy consumption increased with treatment time; thus, this method was more suitable for the pretreatment of high-concentrated azo dye wastewater. Based on the degradation intermediates identification, a simplified degradation pathway for cationic red X-GRL was proposed.