Degradation of real lindane wastes using advanced oxidation technologies based on electrogenerated hydrogen peroxide

Autor(es)

Silva, Taynara O. ; Fernandez-Cascan, Jesus ; Isidro, Julia ; Saez, Cristina ; Lanza, Marcos R. V. ; Rodrigo, Manuel A.

• Tipo de documento: Artigo Científico
• Fonte: PROCESS SAFETY AND ENVIRONMENTAL PROTECTION; v. 180, p. 9-pg., 2023-10-20.

Resumo

In this work, hydrogen peroxide (H2O2) is produced using an optimized electrochemical cell equipped with a gas diffusion electrode (GDE) as cathode, reaching efficiencies as high as 20.1%, when operating in a single compartment configuration, which increases up to the range 50-60, when a proton exchange membrane is used to separate the anodic and cathodic compartments, pointing out the great significance of the anodic oxidation of H2O2 and the scavenging effects of the oxidants produced on the anode surface. As compared to previous materials tested, the GDE implemented in this cell underwent a more sustainable manufacturing procedure and exhibited an outstanding performance. The H2O2 produced electrochemically is dosed to the real leachate of an industrial dump, strongly polluted with derivatives of lindane. This waste is associated to the operation of a large facility in the seventies and contains different isomers of hexachlorocyclohexane and other chlorinated hydro-carbons, produced during the ageing of the dump. Effects of the addition of iron (II) sulfate salts and irradiation of UVC were also evaluated. All electrochemically-assisted technologies evaluated (named as chemical (EACO), Fenton (EAFO), photolysis (EAPO) and photo-Fenton (EAPFO) oxidations) were able to successfully remove the pollutants, although with important differences in the efficiencies reached. Results demonstrate that EACO, that is, oxidation by molecular H2O2 is the most effective treatment for the treatment of this type of wastes, pointing out that activation of H2O2 to hydroxyl radicals, either by electrochemically assisted Fenton or photolysis is not positive for this waste. As well, among the different pollutants contained in the raw waste, removal of hexa-chlorocyclohexane (HCHs) and non-chlorinated volatile organic compounds (VOCs) stands out (both groups being the primary species contained in the wastes). These results are very important not only because of the outstanding productions of H2O2 reached with the novel approach of electrochemical cell used, but also because of the implications of the mechanistic understanding of the attack of H2O2 species in the design of a full-scale application to remediate this real important problem. (AU)

• Processo FAPESP: 22/07227-0 - Eletrodo de difusão gasosa a base de carbono modificado com benzofenona aplicado a co-geração de radicais oxidantes em um reator
• Beneficiário: Taynara Oliveira Silva
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto
• Processo FAPESP: 19/08701-4 - Eletrossíntese de peróxido de hidrogênio utilizando Eletrodos de Difusão Gasosa (EDG) modificados com óxidos metálicos nanoestruturados combinados
• Beneficiário: Taynara Oliveira Silva
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• 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