Electro-Fenton catalyzed by Fe-rich lateritic soil for the treatment of food colorant Bordeaux Red (E123): Catalyst characterization, optimization of operating conditions and mechanism of oxidation

Autor(es)

Ganiyu, Soliu O. ^[1] ; de Araujo Costa, Emily C. T. ^[1] ; Martinez-Huitle, Carlos A. ^[1] ; dos Santos, V, Elisama

Afiliação do(s) autor(es)

^[1] Univ Fed Rio Grande do Norte, Inst Chem, BR-59078970 Natal, RN - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Separation and Purification Technology; v. 242, JUL 1 2020.
• Citações Web of Science: 0

Resumo

In this study, electro-Fenton (EF) process catalysed by iron-rich laterite has been investigated for the degradation of food colorant Bordeaux Red (E123). The laterite was characterized and the effect of catalyst dosage, calcination temperature, initial solution pH and concentration as well as applied current on the decay of the organic matter during the treatment of E123 solution was evaluated. The characterization results showed that the laterite consists of over 30% iron oxides along with significant amount of Al2O3, TiO2 and SiO2. Strong oxidant, major hydroxyl radical ((OH)-O-center dot) was generated in the solution from both homogeneous and heterogeneous catalytic decomposition of electrogenerated H2O2 by Fe3+/Fe2+ redox couple leached into the solution and at the surface of the solid iron oxides. The mineralization efficiency of the process was enhanced by increasing the catalytic dosage up to 8.5 g L-1, calcination temperature up to 400 degrees C and applied current in the range of 50-250 mA, whereas lower COD removal was observed with an increase on the initial solution pH and colorant concentration. At optimum conditions (8.5 g L-1 dosage, 400 degrees C calcination temperature, 0.5 mM initial E123 concentration, pH 3 and applied current of 250 mA using platinum anode and carbon-felt as cathode), complete COD removal (100%) was achieved in less than 4 h of electrolysis, demonstrating the high potential of the laterite-catalysed heterogeneous electro-Fenton (HEF) process for the remediation of organic pollutants. (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