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Using KNbO3 catalyst produced from a simple solid-state synthesis method in a new piezophotocatalytic ozonation hybrid process

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Autor(es):
de Moraes, Nicolas Perciani ; Souto, Robson da Silva ; Campos, Tiago Moreira Bastos ; Thim, Gilmar Patrocinio ; Yu, Lianqing ; Rocha, Robson da Silva ; Rodrigues, Liana Alvares ; Lanza, Marcos Roberto de Vasconcelos
Número total de Autores: 8
Tipo de documento: Artigo Científico
Fonte: CERAMICS INTERNATIONAL; v. 49, n. 18, p. 14-pg., 2023-08-09.
Resumo

The present work reports the development and application of potassium niobate (KNbO3) as a catalyst in a novel hybrid piezophotocatalytic ozonation process aimed at wastewater remediation. Pure KNbO3 samples were produced through a simple solid-state synthesis using water-soluble ammonium niobate (V) oxalate hydrate (C4H4NNbO9.xH2O) as niobium source, employing different potassium precursors (KNO3, K2CO3, KOH, and C8H5KO4). The synthesis was also carried out using powdered niobium oxide as a precursor, aiming to evaluate the differences between the niobates obtained. The results achieved in this study show that all the niobates produced using ammonium niobate (V) oxalate hydrate were composed solely of the orthorhombic structure of KNbO3, while the materials synthesized using niobium oxide exhibited the rhombohedral structure of KNbO3 along with niobium-rich potassium niobates (K3Nb8O21, K2Nb4O21, and KNb3O8) and residual niobium oxide. This behavior was attributed to the enhanced chemical homogeneity derived from the synthesis using ammonium niobate (V) oxalate hydrate, which facilitated the reaction between the components during the thermal treatment step. Furthermore, the optical and morphological properties of the niobates were considerably influenced by the application of different potassium salts. Owing largely to its morphological and electrical properties, the material synthesized using potassium hydrogen phthalate displayed the highest photocatalytic activity in terms of methylene blue discoloration among the niobates produced using C4H4NNbO9.xH2O. Finally, the proposed piezophotocatalytic ozonation process was found to be a highly efficient strategy for the discoloration of methylene blue, as it successfully harnessed the synergy between the multiple mechanisms involving active radical generation toward the development of a highly promising hybrid advanced oxidation process. (AU)

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
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