Catalytic Effect of Hydrogen Peroxide in the Electrochemical Treatment of Phenolic Pollutants using a BDD Anode

Abstract

AbstractPhenolic pollutants are recalcitrant substances that cannot be removed from wastewater using the current treatments. In this study, degradation of phenolic pollutants was studied on the basis of the application of hydrogen peroxide during the electrooxidation process using BDD as anode (EO−H2O2 coupled process). The process was optimized using 4‐chlorophenol (4‐CP) as model compound and later an emerging pollutant, Nonylphenol Ethoxylate‐10 (NP10EO), was degraded using the optimized experimental conditions found. To ascertain treatment effectiveness, experiments with hydrogen peroxide (H2O2), electrooxidation (EO) and EO−H2O2 (coupled process) were carried out. The variables considered in this investigation were pH, current density, quantity of H2O2, and reaction time. It was observed that the coupled process (EO−H2O2) increases degradation efficiency, reaching 81.9 % for 4‐CP and 94.3 % for NP10EO. UV/VIS spectrophotometry, COD and HPLC analysis verified these results. The results of the analysis by cyclic voltammetry after the EO−H2O2 coupled process indicate that pollutants in the solution were efficiently oxidized. It was concluded that small amounts of hydrogen peroxide (250 μL 30 % w/v solution per 1.1 L) are sufficient to attain good results; larger amounts of H2O2 produce inhibitory effects during degradation. The slow cathode (SS) oxidation during the experiments was confirmed by XPS and AFM analysis.