Effects of coupling hybrid processes on the treatment of wastewater containing a commercial mixture of diuron and hexazinone herbicides

Autor(es)

Souza, F. L. ^[1] ; Rocha, R. S. ^[1] ; Ferreira, N. G. ^[2] ; Rodrigo, M. A. ^[3] ; Lanza, M. R. V. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Inst Chem, POB 780, BR-13560970 Sao Carlos, SP - Brazil

^[2] Natl Inst Space Res, BR-12201970 Sao Jose Dos Campos - Brazil

^[3] Univ Castilla La Mancha, Dept Chem Engn, Fac Chem Sci & Technol, Campus Univ S-N, E-13071 Ciudad Real - Spain

• Tipo de documento: Artigo Científico
• Fonte: Electrochimica Acta; v. 328, DEC 20 2019.
• Citações Web of Science: 2

Resumo

This work evaluates the effects of coupling Conductive Diamond Electrochemical Oxidation (CDEO) with electrogenerated peroxide (CDEO-H2O2), iron (II) catalyst (electro-Fenton, EF) and UV irradiation (photoelectron-Fenton, PEF) techniques for the treatment of wastewater containing a commercial mixture of Diuron and Hexazinone herbicides. Although the techniques employed in this study exhibited significant differences in terms of current charge, energy consumption and amounts of byproducts formed, they have shown to be capable of degrading and mineralizing both herbicides (Diuron and Hexazinone). The application of electrooxidation technique with and without hydrogen peroxide generation led to the oxidation of both herbicides, where removal rates ranging from 74% to 99% and 77% -92% were obtained for Hexazinone and Diuron, respectively. Hexazinone and Diuron were completely removed after 90 min in the EF process. PEF was found to be the most efficient technique for having drastically reduced the time for complete degradation of the herbicides, although 25% of organic carbon remained in solution after 120 min of electrolysis. Higher rates of herbicides degradation were obtained in this order: PEF > EF > CDEO/H2O2/UV > CDEO/H2O2 > CDEO > UV. The result indicates that the production of oxidants is promoted by the hybrid processes, and this leads to an improvement in the oxidation of the pollutants. The synergistic coefficient obtained for the coupled techniques were higher than one in terms of both herbicides degradation and Total Organic Carbon (TOC) removal. Two important sub-products of reaction were identified, and their degradation route is in agreement with the reports published in the literature. Essentially, this work draws attention to the synergistic effect caused by the coupling of techniques involving the treatment of chemical agents in wastewater and sheds light on how to use this coupling technique for the development of more efficient treatment processes. (C) 2019 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 14/50945-4 - INCT 2014: Instituto Nacional de Tecnologias Alternativas para Detecção, Avaliação Toxicológica e Remoção de Micropoluentes e Radioativos
• Beneficiário: Maria Valnice Boldrin
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/15000-6 - Processos eletro-oxidativos aplicados na degradação de herbicidas empregados na Orizicultura
• Beneficiário: Fernanda de Lourdes Souza
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 17/10118-0 - Estudo e aplicação da tecnologia eletroquímica para a análise e a degradação de interferentes endócrinos: materiais, sensores, processos e divulgação científica
• Beneficiário: Marcos Roberto de Vasconcelos Lanza
• Modalidade de apoio: Auxílio à Pesquisa - Temático