Peracetic acid enhanced electrochemical advanced oxidation for organic pollutant elimination

Abstract

A synergistic process adding peracetic acid (PAA) in electrochemistry (EC) was established to eliminate organic contaminants in water as a novel advanced oxidation process (AOP). The introduced PAA could be activated by the EC system, substituting electrolyte and promoting the methylene blue (MB) removal than the sole PAA and conventional EC systems. A series of scavenging tests demonstrated that the activation products were hydroxyl radical (HO·) and organic radicals (R-O·) in this EC/PAA process, which both played the dominant role for the MB decontamination. The effect of PAA dose, current density, initial pH, and initial MB concentration on the MB decolorization were investigated, and the results indicated that 93.99% MB was removed with the optimized conditions of 3.6 mmol L−1 PAA, 7.5 mmol L−1 H2O2, initial pH 3, and 10 mg L−1 MB concentration. The influence of water matrix (Cl−, HCO3−, SO42−, and humic acid) for removing MB was determined, and the results showed that the MB removal was considerably inhibited by these constituents of water. Lastly, the decomposition mechanism for the MB was suggested through the outcome of mass spectrometry. This study demonstrated that the EC/PAA process could be a feasible method, advancing the development of AOP for water treatment.