Toxicological Profile of 1,4-Benzoquinone and Its Degradation By-Products during Electro-Fenton, Electrocoagulation, and Electrosynthesized Fe(VI) Oxidation

Abstract

This paper reports on the degradation of 1,4-benzoquinone (1,4-BQ) and its toxic behaviors in association with the formation of degradation by-products during electro-Fenton (EF), electrocoagulation (EC), and electrosynthesized Fe(VI) oxidation. The results of the study show that all these electrochemical processes (EPs) yielded a complete 1,4-BQ degradation. Fe(VI) oxidation provided considerably faster degradation than did the others. Hydroquinone, catechol, and oxalic acid as by-products of oxidation have been identified by high-performance liquid chromatography analysis for each process. The concentration of intermediates varied differently when the EPs were compared. The intermediate formation against time was reasonably correlated with the toxicity trends determined from the inhibition of Vibrio fischeri luminescence. After the EF and EC processes, the level of toxicity remained close to that of raw 1,4-BQ solution. However, Fe(VI) oxidation noticeably reduced the toxicity and the higher 1,4-BQ degradation.