70 resultados para biological activated carbon


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Biosorption of neodymium in batch experiments took similar to 2 h to achieve the equilibrium biosorbent-metal for all microorganisms tested. The best biosorption coefficient at a constant pH value of 1.5 was obtained using the microalgae Monoraphidium sp. (1521 mg g(-1) cell), followed by Bakers' yeast (313 mg g(-1) cell), Penicillium sp. (178 mg g(-1) cell), and activated carbon (61 mg g(-1) cell). When compared to the biosorption of other metals, these results pointed out to the application of biosorption in neodymium recovery from acidic solutions. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

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The adventitious rooting process of in vitro cultured plantlets is a technique that has been employed for the vegetative propagation of a significant number of native and exotic species. Many factors are associated with the rooting stage influencing positive and/or negatively the establishment of micropropagation protocols. The objective of this work was a literature review of the main inherent factors concerning in vitro rooting process including the correlation among others the endogenous and exogenous auxins levels, juvenility, genotype, mineral nutrition, culture medium conditions, addition of growth regulators and other substances as phenolic compounds and active coal besides growth environmental conditions of in vitro cultures. Although the complete elucidation of all processes involved with rooting of in vitro cultured plants has not been achieved so far, a comprehensive study of the main factors that interfere on rooting is fundamental for the establishment of new researches that might contribute for the rooting of economically important plants.

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The cultivation of sugarcane demands the use of herbicides such as Diuron and Hexazinone. Some supply wells from Ribeirão Preto, SP, Brazil, built in the Guarani Aquifer are located in recharge points, and the presence of sandy Quartzarenic Neosol in these areas increases the vulnerability of the groundwater to contamination from herbicides This paper reports the water quality monitored in some wells located in the recharge area and the removal of Diuron and Hexazinone by means of adsorption in granular activated carbon (GAC), preceded or not by preoxidation with chlorine and chlorine dioxide in a pilot plant. The results indicated that Diuron was more strongly adsorbed than Hexazinone and that the saturation time of the GAC in the test with preoxidation was shorter than in the test without preoxidation, which may have occurred mainly due to the formation of by-products that competed with the adsorption of the herbicides.

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The aims of this study were to characterize the microstructure of a commercially pure titanium (cpTi) surface etched with HCl/H 2SO 4 (AE-cpTi) and to investigate its in vitro cytocompatibility compared to turned cpTi (T-cpTi). T-cpTi showed a grooved surface and AE-cpTi revealed a surface characterized by the presence of micropits. Surface parameters indicated that the AE-cpTi surface is more isotropic and present a greater area compared to T-cpTi. The oxide film thickness was similar between both surfaces; however, AE-cpTi presented more Ti and O and less C. Osteoblastic cell proliferation, alkaline phosphatase activity, and bone-like nodule formation were greater on T-cpTi than on AE-cpTi. These results show that acid etching treatment produced a surface with different topographical and chemical features compared to the turned one, and such surface modification affected negatively the in vitro cytocompatibility of cpTi as demonstrated by decreasing culture growth and expression of osteoblastic phenotype.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Engenharia Civil - FEIS

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)