Síntese de nanopartículas de CoFe2O4 e NiFe2O4 pelo método Sol-Gel adaptado

• Ano de defesa: 2018
• Autor(a) principal: Ribeiro, Jomar José Knaip
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Energia; UFES; Programa de Pós-Graduação em Energia
• Palavras-chave em Português: Ferrite; Spinel; Waste; Passion fruit; Orange; Espinélio; Sol-Gel; Maracujá; Laranja; Resíduos; Nanopartículas; Ferrita; Engenharia/Tecnologia/Gestão; 620.9
• Link de acesso: http://repositorio.ufes.br/handle/10/10335

The objective of this study was to evaluate the production of AFe2O4 (A = Co ou Ni) spinel type ferrites using an alternative route for the preparation of nanomaterials, from the insertion as a reaction medium of dry particulate tailings from the processing of orange or passion fruit juice. For the characterization of the materials, the techniques of Fourier Transform Infrared Spectroscopy (FTIR), X- ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used. For the nickel and cobalt ferrites, the precursors were produced by means of the solution between nitrates, distilled water and dry particulates of the tailings, being placed in a refractory and sent to a conventional kiln under the conditions of 353 K for 24 h. Specifically for cobalt ferrite, the orange tailings were used, and particulate concentrations were evaluated at the levels of 20, 40 and 60 gL-1 , as well as the calcination temperature of 873, 973, 1073 and 1173 K for 6h to obtain the nanometric powders. Both factors proved to be favorable for the synthesis of materials, but the concentration was more significant for obtaining cobalt ferrite powders, as higher purity levels were obtained in the 60 g.L-1 condition. The effect of calcination time was evaluated under the conditions of 873 K for 1, 2, 3 and 6h, but this factor was not significant. From the optimum values for concentration and calcination time, the nickel ferrites were produced using the passion fruit tailings, using different temperatures for the isothermal treatment under the conditions of 573, 673, 773, 873, 973, 1073, 1173 and 1273 K and 1 h. For the synthesis, the same behavior of the orange particles was observed, obtaining nanocrystalline ferrite materials with spinel-like structure having a high degree of purity with a positive influence on this parameter from the calcination temperature. The results were satisfactory with percentages of the ferrite phase above 98% for both materials produced.