Investigation of the influence of the anode composition of DSA-type electrodes on the electrocatalytic oxidation of phenol in neutral medium

Autor(es)

Paula D. P. Alves ^[1] ; Magali Spagnol ^[2] ; Germano Tremiliosi-Filho ^[3] ; Adalgisa R. de Andrade ^[4]

Afiliação do(s) autor(es)

^[1] Universidade de São Paulo. Faculdade de Filosofia Ciências e Letras. Departamento de Química - Brasil

^[2] Universidade de São Paulo. Faculdade de Filosofia Ciências e Letras. Departamento de Química - Brasil

^[3] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

^[4] Universidade de São Paulo. Faculdade de Filosofia Ciências e Letras. Departamento de Química - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Chemical Society; v. 15, n. 5, p. 525-533, 2004-10-00.

Resumo

In this paper, phenol oxidation was used as a probe reaction to carry out a systematic investigation of the electrocatalytic activity of DSA-type anodes with nominal compositions equal to Ti/Ru0.3M0.7O2 and Ti/Ir0.7M0.3O2 (M = Ti and Sn) in 1.0 mol L-1 NaClO4. Under CV conditions, phenol oxidation favors polymerization that completely blocks the electrode activity after few cycles independently of the anode material. The following intrinsic catalytic efficiency was observed under CV conditions: Ti/Ru0.3Ti0.7O2 >> Ti/Ru0.3Sn0.7O2 > Ti/Ir0.7Ti0.3O2 > Ti/Ir0.7Sn0.3O2. However, electrolysis experiments (i = 40/80 mA cm-2) run in laboratory-scale showed that the proper choice of anode material can improve the yields of CO2 as final product. HPLC and TOC techniques were used in order to quantify the electrode efficiency. It is important to emphasize that all anodes presented good ability to oxidize the phenolic portion, and a TOC reduction as high as 80% was observed for the Ti/Ru0.3Ti0.7O2 electrode. Benzoquinone formed in the beginning of the electrolysis is continuously oxidized as the reaction proceeds. Malic, tartaric and malonic acids were also identified as other by-products of phenol oxidation. (AU)

• Processo FAPESP: 01/10338-1 - Oxidação de substâncias orgânicas tóxicas utilizando ânodos dimensionalmente estáveis ativados
• Beneficiário: Adalgisa Rodrigues de Andrade
• Modalidade de apoio: Auxílio à Pesquisa - Regular