Chromium Iii
Mostrando 13-24 de 84 artigos, teses e dissertações.
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13. Speciation and preconcentration of chromium from water and food samples by synthesized chelating resin
A resina poli(ácido N,N'-dipropionitrila metacrilamida-co-divinilbenzeno-co-2-acrilamida-2-metil-1-propanosulfonico) foi sintetizada com um novo adsorvente quelante para especiação de cromo em amostras de água e alimento por espectrometria de absorção atômica com chama (FAAS). A resina foi caracterizada por espectroscopia no infravermelho por transfor
J. Braz. Chem. Soc.. Publicado em: 2013-05
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14. Especiação redox de crômio em amostras de solos contaminados / Redox especiation of chromium in contaminated soil samples
Chromium and its compounds are employed in various industrial processes, and these activities are responsible for the disposal of significant amounts of materials containing this element in the environment. Due to the known toxic feature of Cr(VI) in biological systems, the determination of chromium species has acquired great importance in environmental chem
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/03/2012
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15. Mathematical modeling for digestible protein in animal feeds for tilapia
The objective of this study was to formulate mathematical models to estimate digestible protein in some animal feeds for tilapia. Literature results of the proximate composition of crude protein, ether extract, and mineral matter, as well as digestible protein obtained in biological assays, were used. The data were subjected to multiple linear stepwise backw
Revista Brasileira de Zootecnia. Publicado em: 2012-06
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16. Highly improved chromium (III) uptake capacity in modified sugarcane bagasse using different chemical treatments
The present paper focuses on improving chromium (III) uptake capacity of sugarcane bagasse through its chemical modification with citric acid and/or sodium hydroxide. The chemical modifications were confirmed by infrared spectroscopy, with an evident peak observed at 1730 cm-1, attributed to carbonyl groups. Equilibrium was reached after 24 h, and the kineti
Quím. Nova. Publicado em: 2012
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17. Estudo da sorção de íons de CR(III) utilizando a macrófita aquática Lemna minor / Study of CR(III) ions biosorption using the aquatic macrophyte Lemna minor
Nas últimas décadas tem-se observado sérios impactos ambientais tendo o desenvolvimento tecnológico e industrial como fonte geradora no que diz respeito ao descarte sem controle de substâncias poluentes no meio ambiente, em particular, a poluição dos recursos hídricos. Diversos problemas relacionados a crescentes despejos de metais pesados em corpos
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/05/2011
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18. The influence of Chromium supplied by tanning and wet finishing processes on the formation of cr(vi) in leather
Chromium used in leather manufacturing can be oxidized from the trivalent to the hexavalent state, causing environmental concerns. In this study, the influence of Cr(III) from tanning, deacidification pH, fatliquors, chrome retanning and vegetable retanning on the formation of Cr(VI) in leather was analyzed by comparing natural and aged samples. In wet-blue
Brazilian Journal of Chemical Engineering. Publicado em: 2011-06
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19. Evaluatin of metabisulfite and a commercial stee wool for removing chromium (VI) from wastewater.
Efficiency of metabisulfite and a commercial steel wool as reducing agents in the removal of Cr(VI) from wastewaters was evaluated. Chromium( VI) was converted to Cr(III), precipitated with NaOH, and removed by filtration. A reduction of more than 1.0 x 10(5) and 4.0 x 10(5) fold in total Cr and the Cr(VI) concentrations, respectively, was observed by employ
Enviromental Chemistry Letter. Publicado em: 2011
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20. Pré-concentração de Cr(III) e análise de especiação de cromo empregando montmorilonita saturada com íons potássio
The clay mineral montmorillonite-K10 (MT), treated under acidic medium and saturated with potassium ions (MTK), was employed in sorption and desorption studies aiming the preconcentration of Cr(III) and the speciation analysis of chromium. The sorption process of Cr(III) was close to 100%, suggesting that MTK was a good material for Cr(III) preconcentration,
Química Nova. Publicado em: 2011
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21. Substituted tridentate pyrazolyl ligands for chromium and nickel-catalyzed ethylene oligomerization reactions: effect of auxiliary ligand on activity and selectivity
Dois novos complexos de cromo(III) contendo ligantes tridentados [CrCl3(L)] (1a, L = bis[2-(3-fenil-1-pirazol)etil)]amina; 2a, L = bis[2-(3-metil-5-fenil-l-pirazol)etil]sulfeto) foram preparados e caracterizados por análise elementar. Após ativação com metilaluminoxano (MAO), estes pré-catalisadores mostraram altas frequências de rotação nas reaçõe
Publicado em: 2011
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22. Estudo da especiaÃÃo do cromo no processo de adsorÃÃo por carvÃo ativado usando a espectroscopia de emissÃo de raios X Kβ / Study of the chromium speciation during the adsorption process on activated carbon as assessed by X-ray Kβ emission spectroscopy
Este trabalho visa estudar a reduÃÃo do cromo hexavalente à forma trivalente atravÃs do processo de adsorÃÃo, avaliada pela espectrometria Kβ de emissÃo. Amostras de carvÃo ativado foram utilizados como material adsorvente, enquanto a resina Amberlite IR 120 foi usada como um indicador da presenÃa de Cr(III) em todas as soluÃÃes contendo Cr(V
Publicado em: 2011
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23. Redução de cromo hexavalente por bactérias isoladas de solos contaminados com cromo / Reduction of hexavlent chromium by isolated bacteria of contaminated soils with chromium
A redução do Cr(VI) para Cr(III) diminui a toxidade deste metal no ambiente, uma vez que o Cr(III) é insolúvel às membranas biológicas. Assim, a redução microbiana do Cr(VI) é uma alternativa para reduzir os impactos ambientais causados por este metal, utilizado em diversos processos industriais. O objetivo deste trabalho foi selecionar microrganism
Publicado em: 2010
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24. APLICAÇÃO DE MÉTODOS VOLTAMÉTRICOS DE ANÁLISE NA ESPECIAÇÃO DE CROMO, SELÊNIO E ANTIMÔNIO EM MATRIZES SALINAS / APPLICATION OF VOLTAMMETRIC METHODS TO THE SPECIATION ANALYSIS OF CHROMIUM, SELENIUM AND ANTIMONY IN SALINE MATRICES
This work aimed to explore the speciation analysis of chromium, selenium and antimony, elements of clinical and geochemical relevance, in the saline samples seawater, hydrothermal fluid and hemodialysis fluid. These samples, although linked to different research areas, have many similarities relating to their chemical compositions or the presence of metallic
Publicado em: 2010