Degradação fotocatalítica de rodamina b utilizando ferritas de cobre e níquel sintetizadas pelo método de complexação combinado edta-citrato

Abstract

World pollution has increased due to increasing global industrialization. The aquatic environment is one of the most affected, with many different types of pollutants being found, which cause variation in the original characteristics of water bodies. Dyes make up a class of these pollutants, which have an organic nature and resistance to conventional treatments, requiring the application of more effective processes such as Advanced Oxidative Processes (AOP's), for the treatment of contaminated environments. AOP's cover a wide range of processes, including methods that use semiconductor catalysts to promote the generation of hydroxyl radicals (HO•), such as heterogeneous photocatalysis. The nature of these materials is diverse, and spinel ferrites have these semiconductor properties, with the general formula, MFe2O4, they are magnetic, chemically and mechanically stable, where M represent cations of divalent metals, which can be composed of a mixture of these cations, the in order to better adjust the properties of the materials. In this work, the study of the use of mixed ferrites of copper and nickel (NixCu(1-x)Fe2O4) in different proportions (x = 0; 0.2; 0.8 and 1) was carried out to photocatalytically degrade the dye Rhodamine B, simulating an industrial effluent. The mixed copper and nickel ferrites were synthesized by the combined EDTA-Citrate complexation method, and characterized by the techniques of XRD, Ritveld Refinement, SEMFEG, EDS, TG, FT-IR and ERD UV-Vis. Preliminary tests were proposed to evaluate the degradation of the Rhodamine B dye, namely: self-degradation, photolysis and photocatalysis, with the photocatalytic degradations presenting better results. Finally, the effect of reaction parameters: catalyst load and pH on degradation was studied to establish the best reaction conditions, which were achieved for a catalyst load of 0.62 g/L, pH = 10 and dye concentration of 10 ppm. The samples containing the highest copper content (CuFe2O4 and Ni0.2Cu0.8Fe2O4) obtained the best degradation results with approximately 60% removal of the Rhodamine B dye.