IG - Instituto de Geociências
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2172
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Item Acesso aberto (Open Access) Adsorção de molibdato em minerais de argilas naturais e modificadas com ácido sulfúrico, ácido húmico e uréia(2013-03) PEREIRA, Patrícia Magalhães; LEMOS, Vanda Porpino; RODRIGUES, E.; FAIAL, Kelson do Carmo FreitasClay sediments from the municipalities Assis Brazil (Acre), were leached with solutions of sulfuric acid, humic acid and urea, to evaluate the retention capacity of molybdate in these materials and to investigate the feasibility of the adsorption processes at solid-solution interfaces. The materials were characterized from data of XRD, FTIR spectra, surface charge and chemical composition. The Langmuir isotherm models, Freundlich and Sips were used to fit the experimental data of adsorption. The minerals identified in the clay sediments were smectite, kaolinite, illite, quartz, albite, calcite and microclineo. The chemical modification leads amorphization of the modified sample with sulfuric acid and delamination along the plane 001 of the modified sample with urea. The settings defined by mathematical parameters (KL,Kf) of the adsorption isotherms, evaluation Ce vs. qe, pH vs. Qe, Qmax (sips) and Kd, indicated that the S10H15 sample is more efficient in the adsorption MoO42- ,with com qMax = 6.83 mg. L-1.Item Acesso aberto (Open Access) Influência do método de síntese no processo de pilarização com titânio de uma esmectita da região amazônica(2006-12) GUERRA, Denis de Jesus Lima; LEMOS, Vanda Porpino; ANGÉLICA, Rômulo Simões; AIROLDI, ClaudioSmectite clays of the State of Acre, Brazil, were used for the pillarization process. The natural and pillarized matrices were characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermal analysis, scanning electron microscopy, energy dispersive spectroscopy and textural analysis. The titanium pillarized solutions Ti(OC2H5)4 and TiCl4 were analyzed by FTIR. The intercalation ion was obtained by reacting Ti(OC2H5)4 with HCl (HCl/Ti ~ 1) and TiCl4 with ethanol (Ti/clay ~ 25 mmol Ti/g). The notronite intercalation was carried out using two methods: with dropwise hydrochloric acid in titanium ethoxide solution, and using titanium tetrachloride, kept under vigorous stirring at 25 °C for 3 h and calcination at 450 °C and 600 °C. The X-ray diffraction results of the pillarization process show an increase (15.30 Å to 18.76 Å) in the basal spacing of the natural clay and in the specific surface area (44.37 m2/g to 188.72 m2/g) The thermal stability of the natural clay was improved by the pillarization procedure.Item Acesso aberto (Open Access) Nutrientes (K, P, Ca, Na, Mg e Fe) em sedimentos (solos aluviais) e cultivares (feijão e milho) de praias e barrancos de rios de água branca: a bacia do purus no estado do Acre, Brasil(2009) MARTINS, Milta Mariane da Mata; COSTA, Marcondes Lima daThe present research highlights the macronutrient abundance in the sediments of beaches and cliffs and cultivates in the river Purus and flowing, southwest of Amazon. The concentrations found in leaves and bean seeds and corn leaves reflect the mineralogical and chemical nature of those rich sediments in K2O and Na2O, which are formed by smectite, illite and K-feldspar. The factors of transfer of the elements in the corn leaves and bean (Ca>K>Na) and bean seeds (Na>K>Ca) demonstrate that the nutrient needs of the cultivate were found appropriately in the sediments (soils) of the beaches and cliffs.