Navegando por Autor "RODRIGUES, Emerson Cardoso"

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Acesso aberto (Open Access)
Estudo da influência do tempo de reação e do teor de “Na” na síntese de zeólitas
(Universidade Federal do Pará, 2013-04-05) RODRIGUES, Emerson Cardoso; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
This work aims to synthesize zeolite type "A" using as raw kaolin filler. The synthesis of zeolites was performed in a short time and without agitation. The starting materials and the product were identified and characterized by X ray Diffraction (XRD), Fluorescence Spectrometry, X Ray, Scanning Electron Microscopy (SEM), Grain Size Analysis and Gravimetric and Differential Thermal Analysis (DTA and TG). In the synthesis process was used as the silica source and the alumina metakaolinite, which has been calcined at a temperature of 600 ° C for 2 hours threshold firing in a muffle type furnace. As a source of sodium was used a solution of sodium hydroxide 5 M in the system was also added distilled water. Various syntheses were performed inside an oven at 110 °C. The variation in reaction time and sodium content were the variables in the process. The results of the synthesis of zeolite A proved satisfactory, especially in time of 10 h with a ratio Al / Na = 0.57. The reaction time and amount of sodium are directly proportional to the formation of another phase called zeolitic Hydroxysodalite. From the zeolite A, by ion exchange with a solution of calcium chloride was obtained zeolite 5A without agitation.
Acesso aberto (Open Access)
Produção de material zeolítico a partir de caulim da Amazônia em escala semi piloto: aplicação na adsorção de cobre
(Universidade Federal do Pará, 2019-06-27) RODRIGUES, Emerson Cardoso; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
This work aims to synthesize a zeolite product composed of zeolite type "A" plus sodalite using as filler kaolin starting material. The synthesis of Zeolites was carried out in a short time and in a system with agitation, in a reactor of stainless steel with a volume of approximately 0.001 m3, that is, in semi-pilot scale. The system was heated by steam from a boiler. The X ray diffraction (XRD), X ray Fluorescence Spectrometry, Scanning Electron Microscopy (SEM), Granulometric Analysis and Differential and Gravimetric Thermal Analysis (DTA and TG) were identified and characterized. In the synthesis process the metakaolin was used as the source of silica and alumina, which was obtained at 600 ° C for 2 hours of calcination in a muffle furnace. A 5M sodium hydroxide solution was used as the sodium source. Several syntheses were carried out for a maximum duration of 180 minutes. Every 30 minutes aliquots of the product were taken for the study of reaction kinetics. The results of the zeolite syntheses were satisfactory and the product obtained was applied to the adsorption of Cu2+ ions, in which the influence of the variables: time, temperature, pH and adsorbent quantity were evaluated. The determination of the best adsorption model was performed by the Monte Carlo method via Markov Chain and through the Akaike Information Criterion the isotherms that were closest to the presented results were established. The results obtained were compared with other studies available in the literature and showed significant values, which characterize the process of zeolite production and adsorption as promising and efficient.
Acesso aberto (Open Access)
Produção de zeólita analcima a partir de caulim amazônico
(2013-12) MORAES, Cristiane Gomes; RODRIGUES, Emerson Cardoso; ANGÉLICA, Rômulo Simões; MACÊDO, Emanuel Negrão; NEVES, Roberto de Freitas
In the north of Brazil large mineral reserves are found, which have been exploited in recent decades typically generating large volumes of waste to the environment. In the specific case of the kaolin is the main product exported is for paper coating (commodity) with low value. Its production also generates a massive waste composed mainly of high purity kaolinite, but with no specification to cover paper, being discarded or used in other less noble application. As zeolites are more noble materials and present silica and alumina, one of the goals of this work was the development of the production process of the zeolite analcime from kaolin waste, diatomite and sodium hydroxide solution. In the other hand, the methods described for obtaining zeolites are developed in an alkaline medium, typically using an excess of sodium hydroxide in the reaction, causing environmental and economic problems. The synthesis process of zeolite analcime semi-continuous is described, using excess of sodium hydroxide to be recovered and reused in a new process cycle. The process consisted in five consecutive cycles in an autoclave by reaction of calcined kaolin, diatomaceous earth as a source of additional silica, aqueous solution of sodium hydroxide, and fresh sodium hydroxide solution, and recycled. The reaction process was developed at 210 °C for 24 h. The product obtained at the end of each cycle was analcime zeolite characterized by XRF, XRD, DTA / TG, SEM. The production process of analcime showed high yield and reuse of sodium hydroxide through recycle to be technically feasible.