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

Author(s)

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

• Document type: Journal article
• Source: JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING; v. 13, n. 2, p. 13-pg., 2025-04-25.

Abstract

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)

• FAPESP's process: 20/02743-4 - Fe/RuO2-TiO2 films supported on carbon felt for norfloxacin degradation by heterogeneous electro-fenton process
• Grantee: Géssica de Oliveira Santiago Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/22210-0 - EMU granted in process 2017/10118-0: liquid chromatograph (HPLC)
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 19/06650-3 - EMU granted in the 2017/10118-0 process: potentiostat system with impedance module
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 18/22022-0 - EMU granted in the 2017/10118-0 process: spectroelectrochemistry system
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 16/19612-4 - Degradation of endocrine disruptors carbofuran, methylparaben and propylparaben via electrogenerated H2O2 and associated processes (electrogenerated H2O2/UV, electro-Fenton e photoelectro-Fenton)
• Grantee: Paulo Jorge Marques Cordeiro Junior
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 22/12895-1 - Advanced processes for the degradation of emerging pollutants: catalytic materials, electroanalytical sensors and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/22211-7 - EMU granted in process 2017/10118-0: total organic carbon analyzer (TOC)
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program