Ferritas de Cobalto obtidas pelo método de coprecipitação: caracterização e atividade fotocatalítica para a descoloração aquosa de corante
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Data
2021-10-08
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Universidade Estadual Paulista (Unesp)
Resumo
As ferritas são materiais que apresentam propriedades físicas interessantes, aliadas a uma boa estabilidade química e a diversos campos de aplicação, como catálise e fotocatálise. Entre as ferritas destaca-se a ferrita de cobalto, de estrutura espinélio inverso, que possui propriedades superparamagnéticas, alta coercividade e anisotropia, além de apresentar elevada estabilidade química e física. Este trabalho tem como objetivo investigar a síntese e atividade fotocatalítica das ferritas de cobalto, de estequiometria CoxFe3-xO4, onde 0,4 ≤ x ≤ 1,2, obtidas pelo método de coprecipitação na descoloração de soluções de corante. Os pós sintetizados foram caracterizados pelas técnicas de difração de raios X, espectroscopia na região do Infravermelho (FTIR) e espectroscopia de reflectância difusa UV-Vis. A morfologia das partículas foi acompanhada por microscopia eletrônica de varredura (MEV), indicando a formação de partículas aproximadamente esféricas. A atividade fotocatalítica das partículas foi investigada pelo processo de descolaração do corante Rodamina 6G, na presença de luz ultravioleta, em um período de 240 minutos. As ferritas de cobalto apresentaram uma atividade fotocatalítica em torno de 80% na descoloração do corante Rodamina 6G, com melhores resultados em meio básico.
Ferrites are materials that have interesting physical properties combined with good chemical stability and several fields of application, such as catalysis and photocatalysis. Among the ferrites stands out the cobalt ferrite, with inverse spinel structure, that has superparamanetic properties, high coercivity and anisotropy, besides presenting good chemical and physical stability. This project aims to investigate the synthesis and photocatalytic activity of cobalt ferrites with stoichiometry CoxFe3-xO4, where 0.4 ≤ x ≤ 1.2, obtained by the coprecipitation method in the decolorization of dye solutions. The powders synthesized were characterized by X-ray diffraction, Infrared spectroscopy (FTIR) and UV-Vis diffuse reflectance spectroscopy. The morphology of the particles was followed by scanning electron microscopy (SEM), indicating the formation of approximately spherical particles. The photocatalytic activity of the powders was investigated by the discoloration process of the Rhodamine 6G dye, in the presence of ultraviolet light, in a period of 240 minutes. Cobalt ferrites showed a photocatalytic activity in about 80% in the discoloration process of the Rhodamine 6G dye solution, with better results in basic medium.
Ferrites are materials that have interesting physical properties combined with good chemical stability and several fields of application, such as catalysis and photocatalysis. Among the ferrites stands out the cobalt ferrite, with inverse spinel structure, that has superparamanetic properties, high coercivity and anisotropy, besides presenting good chemical and physical stability. This project aims to investigate the synthesis and photocatalytic activity of cobalt ferrites with stoichiometry CoxFe3-xO4, where 0.4 ≤ x ≤ 1.2, obtained by the coprecipitation method in the decolorization of dye solutions. The powders synthesized were characterized by X-ray diffraction, Infrared spectroscopy (FTIR) and UV-Vis diffuse reflectance spectroscopy. The morphology of the particles was followed by scanning electron microscopy (SEM), indicating the formation of approximately spherical particles. The photocatalytic activity of the powders was investigated by the discoloration process of the Rhodamine 6G dye, in the presence of ultraviolet light, in a period of 240 minutes. Cobalt ferrites showed a photocatalytic activity in about 80% in the discoloration process of the Rhodamine 6G dye solution, with better results in basic medium.
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Ferrita de Cobalto, Coprecipitação, Fotocatálise, Cobalt Ferrite, Coprecipitation, Photocatalysis