Electrochemical degradation of tebuthiuron pesticide using a flow reactor: Insights into the co-generation of oxidants and ecotoxicological risks

Autor(es)

Souto, Robson S. ; Sanchez-Montes, Isaac ; Santos, Gessica O. S. ; Cordeiro-Junior, Paulo J. M. ; Colombo, Renata ; Santos, Mauro C. ; Lanza, Marcos R. V.

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING; v. 13, n. 2, p. 13-pg., 2025-04-25.

Resumo

Innovative contaminants treatment approaches are essential to addressing persistent environmental contamination from pesticides such as tebuthiuron (TBT), as they provide us with more effective and safer alternatives to traditional degradation methods. A notable advanced treatment approach is the combined electrochemical process which involves ultraviolet-C (UVC) activation of in-situ electrogenerated H2O2 and chlorine species - the combined UVC/e-H2O2@e-ClO- system. This method uses an electrochemical flow reactor equipped with a gas diffusion cathode and a DSA (R)-Cl2 anode, allowing the simultaneous production of both oxidants. Under the best experimental conditions (10 mA cm-2, 10 mmol L -1 of Cl-, and pH 7), the combined UVC/e-H2O2@e-ClO- system promoted over 99.0 % TBT degradation in 60 min of treatment and 63.2 % total organic carbon removal in 90 min, with low energy consumption (1.54 kWh g -1 TOC). The roles of different reactive oxygen species (H2O2, HClO/ClO-, and hydroxyl radicals (HO center dot)) were also evaluated, and a mineralization pathway was proposed based on the analysis of the by-products generated under the different electrochemical conditions. Although several byproducts were detected during the degradation process, toxicological estimations suggested that these intermediates are less toxic than the parent compound; in this sense, it is evident that the degradation process helps reduce the environmental impact of TBT. Thus, the combined electrochemical process of activating H2O2 and chlorine species effectively degrades organic pollutants in chloride-containing wastewater, offering a sustainable and efficient treatment solution. Additionally, while TBT degradation has been extensively studied in the literature, it is the first time that a combined UVC/e-H2O2@e-ClO- approach has been employed to investigate this contaminant and its toxicity effects following treatment. (AU)

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