01.1 - Graduação (Sede)
URI permanente desta comunidadehttps://arandu.ufrpe.br/handle/123456789/2
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Item Influência de granitos anorogênicos (Tipo A) na geoquímica de elementos terras raras em solo no semiárido brasileiro(2023-02-24) Santana, Laura Mariana Nascimento de; Silva, Ygor Jacques Agra Bezerra da; Nascimento, Rennan Cabral; http://lattes.cnpq.br/5916790861002578; http://lattes.cnpq.br/0904824873761236; http://lattes.cnpq.br/5352138228552126The global demands for rare earth elements (REEs) are continuously increasing and, consequently, the accumulation of these elements in the soil and the environment has caused adverse effects on human and environmental health, causing growing concern not only in the scientific community, but throughout society. The geochemistry of REEs in soils remains poorly understood, particularly in semi-arid environments. Studies on the dynamics of REEs in different geological, pedological and climatic contexts are necessary to understand the different biogeochemical behaviors of these elements. However, there are still no studies on the effect of type A granites on the physical, chemical and mineralogical attributes of soils located in different environmental conditions. Thus, the present work aimed to evaluate the influence of the mineralogy of anorogenic granites (A Type) on the mineralogy and geochemistry of rare earth elements in the Brazilian semi-arid region. The soil profile was selected based on the geological map of Pernambuco. A Type granite was analyzed using a petrographic microscope, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Soil morphology was described based on the Soil Description and Collection Manual in the Field and the soil profile classification was according to the Brazilian Soil Classification System. REEs readings were made by optical emission spectrometry. An X-ray diffractometer was used to identify the minerals in the soil fractions. The soil profile derived from type A granite in the semi-arid region was classified as CAMBISSOLO HÁPLICO Ta Eutrófico Típico, defined by the presence of an incipient B diagnostic horizon (Bi), being deep, not stony, not gravelly and not rocky. Based on the fertilizer recommendation manual for the state of Pernambuco, the natural fertility of the soil profile originating from type A granite was considered moderate. A Type granite showed a high proportion of mafic and accessory minerals, mainly biotite, hornblende, allanite, garnet, opaque minerals and apatite. Bastnasite and monazite weathering were the main sources of REEs in the soil. The average total concentration of REEs in the soil profile originating from A type granite was very high (394.2 mg kg-1), being higher than the average of soils derived from other granite types (I and S Types), as well as from average of the soils of Europe, China, Japan, Sweden and the reference soils of Brazil. Soil derived from A type granite showed REE enrichment, with slight fractionation between LREEs and HREEs. The LaN/YbN ratio slightly higher than one also confirmed the slight fractionation between LREEs/HREEs. There was no fractionation between LREEs (LaN/SmN ratio <1). However, there was a slight fractionation among the HREEs (GdN/YbN ratio > 1) due to these metals being more mobile than the LREEs. The positive cerium (Ce) anomaly is explained by the oxidizing condition of the profile, in which Ce3+ transforms into Ce4+, presenting low solubility and a greater tendency to enrichment. The positive europium (Eu) anomaly is explained by the substitution of Eu by strontium (Sr2+) in plagioclase. Therefore, the positive Eu anomaly in the soil reflects the same geochemical signature in its parent material. The mineralogical composition of A type granite, as well as the mineralogy of the soil, had a strong influence on the geochemistry of REEs in the soil. This study provides evidence of the influence of A type granite on the geochemistry of REEs in soil located in the Brazilian semi-arid region.Item Síntese e caracterização de novos materiais luminescentes à base de glutamato e ítrio(2019-12-09) Valença, Maria Eduarda de Goes; Falcão, Eduardo Henrique Lago; Vila Nova, Suzana Pereira; http://lattes.cnpq.br/7716018904442218; http://lattes.cnpq.br/0614524019382645; http://lattes.cnpq.br/5887132704910210This work focuses on the synthesis of new luminescent materials using as precursors the commercial monosodium glutamate and rare earth ions (yttrium, neodymium and europium), which presented a gel aspect. The methodology used follows a previous work, in which a material containing glutamate and neodymium was obtained. The hypothesis raised was that it would be possible to obtain a similar material replacing the neodymium by the yttrium, based on the similar chemical properties between these two metals. This substitution is justified by the fact that neodymium is about three times more expensive than yttrium. Initially, materials containing only glutamate and yttrium were obtained, which presented a gel aspect, varying the proportions between the metal and the ligand. The proportion (in millimol) that contains the smallest amount of metal in relation to the binder and still forms the material with gel aspect is 1:10, metal-ligand, respectively. However, the proportion chosen to continue the work was 1:5, because it was also employed in the previous work. To the yttrium and glutamate gel were added varying amounts (1 to 50% mol) of neodymium and europium in order to assign luminescent properties to the material. The characterization of the materials included the techniques of infrared spectroscopy, Raman spectroscopy and luminescence spectroscopy. The infrared spectra of the material containing only yttrium and glutamate showed a profile similar to those of the material containing only neodymium and glutamate. The materials containing yttrium, neodymium and glutamate also followed the same profile, while those containing yttrium, europium and glutamate varied minimally. The Raman spectra of the yttrium and glutamate materials coincided with those of neodymium and glutamate. However, those of europium and glutamate materials varied substantially compared to the others. This suggests that the yttrium coordinates to the glutamate similarly to the neodymium does, but the europium coordinates differently. The luminescence spectra were obtained for the material containing only neodymium and for the material containing yttrium and neodymium. The characteristic Nd3+ transitions were observed, and the intensities varied according to the amount of neodymium present in each sample.Item Estudo de propriedades reológicas e espectroscópicas de materiais a base de glutamato monossódico e íons terras raras(2021-07-22) Souza, Danylla Thaiana Teles de Oliveira; Falcão, Eduardo Henrique Lago; http://lattes.cnpq.br/0614524019382645; http://lattes.cnpq.br/5710207526340992In the present work, syntheses of materials formed from commercial monosodium glutamate (GMS) and rare earth ions (RE) La3+ and Y3+ were performed. The methodology used follows that of previous works, carried out by our research group, which obtained new materials from the reaction between GMS and RE ions. This methodology produced transparent, hygroscopic materials with high viscosity. Initially, the 1:1 ratios between TR (La3+ or Y3+) and the ligand (GMS) were chosen for the structure and properties analyses. Subsequently, a small amount (10%) of europium ion (Eu3+) was added to the materials, with the aim of attributing luminescence to the material. For the characterizations rheology measurements and vibrational spectroscopy (infrared and Raman) were used. Through rheological studies it was observed that the viscosity and elasticity parameters vary as the external stress is applied, characterizing the material as a non-Newtonian fluid. The analysis of frequency as a function of storage modulus (G’) and loss modulus (G’’) determined that for high frequencies the system reaches equilibrium, and for low frequencies the system keeps evolving. In addition, it was noted that despite having elasticity, it is not superior to viscosity, with no freezing point. Therefore, the material cannot be classified as a gel. Infrared spectra and Raman spectra were similar in all samples, with minimal variation in the spectra of materials containing yttrium. This suggests that coordination between RE ions and GMS occurs in a similar way.