Navegando por Autor "Furtado, Liliam Quelem Tavares"

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    Desenvolvimento de metodologia analítica utilizando sistema em fluxo e casca de arroz para pré-concentração de chumbo em amostras de sedimento
    (Universidade Federal de Goiás, 2018-06-20) Furtado, Liliam Quelem Tavares; Coelho, Luciana Melo; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4794563A2; Coelho, Luciana Melo; Alves, Vanessa Nunes; Silva, Sidnei Gonçalves da
    The present work presents a study of use of the rice husk as adsorbent material for the determination of lead ions in sediment samples obtained at different points of Rio Doce region (Espírito Santo), using flow injection system. With detection metal determination wes used Atomic Flame Absorption Spectrometry. The physico-chemical characterization of the material was done by Infrared Region Spectroscopy, Scanning Electron Microscopy, X-ray Dispersive Energy Analysis and X-ray Diffraction and determination of the zero load point. In adsorptive processes, the pH directly influences the extraction of the ion and the study of this parameter indicated that in pH 6,00 better extraction conditions are obtained. After pH determination, a multivariate optimization 2 4 of the parameters influencing the ion adsorption process was performed. The variables evaluated were adsorbent mass, preconcentration flow, volume and eluent concentration. Subsequently, a univariate study of the mass and preconcentration flow variables was performed, as well as a study of the elution flow rate. The best responses for flow system operation were obtained using: adsorbent mass 70.0 mg, eluent concentration (HNO3) 0,50 mol L-1 , eluent volume 1000 μL, preconcentration flow 2.0 mL min-1 and elution flow 1.0 mL min-1 . From the optimized conditions, the procedure showed to be effective for the Pb2+ species, with limits of detection (LD) and quantification (LQ), respectively, equal to 0.015 and 0.05 mg L-1, with a relative standard deviation (DPR) of 6.821% and a preconcentration factor of 49.5. Recovery values were obtained between 87 - 100% for fortified sediment samples. In order to analyze the selectivity of the method, the evaluation of possible interferences was carried out, based on the calculation of the interference factor (FI). The Cu (II), Ni (II), Co (II), Fe (III) and Zn (II) ions were analyzed in different proportions. The procedure presented was satisfactory for preconcentration of Pb2+ ions, and it can be used for extraction of the same. As it proved to be fast, efficient, low cost, besides the reduction in reagent consumption and waste generation. Factors that favor the development of a system based on the principles of "Green Chemistry".