A new approach on synergistic effect and chemical stability of graphene oxide-magnetic nanocomposite in the heterogeneous Fenton degradation of caffeine

Autor(es)

Ramirez-Ubillus, Manuel Alejandro ^[1] ; Costa-Serge, Nayara de Melo ^{[1, 2]} ; Hammer, Peter ^[1] ; Pupo Nogueira, Raquel Fernandes ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ UNESP, Inst Chem, BR-14800900 Araraquara, SP - Brazil

^[2] UNESP, Inst Chem, Natl Inst Alternat Technol Detect Toxicol Evaluat, BR-14800900 Araraquara, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Environmental Science and Pollution Research; v. 28, n. 39, p. 55014-55028, OCT 2021.
• Citações Web of Science: 0

Resumo

Two compositions of graphene oxide-magnetite nanocomposites were studied as catalysts in the heterogeneous Fenton process. Transmission electron microscopy and X-ray diffraction revealed that the graphene oxide sheets were covered with nanoparticles of magnetite, with an average crystallite size of 7 nm. Infrared spectroscopy analysis indicated that the phases interacted through covalent Fe-O-C bonds. The composites presented significantly improved catalytic activity, compared to pure magnetite, with a synergistic effect of up to a factor of 17.1 for the Fenton degradation of caffeine, achieving total removal after 90 min. This synergistic effect was a consequence of the interaction between the phases, resulting in improved mass transfer of caffeine to the catalyst surface, adsorption and efficient degradation, with enhanced HO center dot generation. The surface reaction constant increased by up to three orders of magnitude, demonstrating the important role of graphene oxide in the degradation kinetics of the heterogeneous Fenton process. The surface-bonded hydroxyl radicals were responsible for caffeine degradation, achieving 9.4 mu mol L-1. After five degradation cycles, a loss of Fe-O-C bonds and increase in oxygenated groups were associated with a small decrease of caffeine removal efficiency, from 98 to 82%, without significant iron leaching, in the dark, and with low consumption of hydrogen peroxide. (AU)

• Processo FAPESP: 18/17517-0 - Hidróxidos duplos lamelares como catalisadores em processo foto-Fenton heterogêneo para a degradação de fármacos presentes em efluente hospitalar
• Beneficiário: Nayara de Melo Costa Serge
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• 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