Cr Vi
Mostrando 13-24 de 229 artigos, teses e dissertações.
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13. Kinetic Analysis of the Decomposition of the KFe3(SO4)2-x(CrO4)x(OH)6 Jarosite Solid Solution in Ca(OH)2 Medium
The decomposition of the solid solution of potassium jarosite with chromium(VI) in Ca(OH)2 media was studied in the present work. According to experimental results, the incorporation of CrO42- into the crystal structure of jarosite resulted in a solid solution with the following approximate formula: [K0.86(H3O)0.14]Fe2.67[(SO4)1.23(CrO4)0.77][(OH)5.01(H2O)0.
J. Braz. Chem. Soc.. Publicado em: 2016-06
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14. Magnetic Nanoparticles Coated with Ionic Liquid as a Sorbent for Solid Phase Extraction of Chromium(VI) Prior to Its Determination by Electrothermal Atomic Absorption Spectrometry
A simple, sensitive and reliable method for the separation, preconcentration and determination of ultra trace amounts of chromium species has been developed. Chromium(VI) in aqueous sample was reacted with 9-phenyl-2,3,7-trihydroxy-6-fluorone to produce a chelate at pH of 5.0 and extracted onto the magnetic nanoparticles coated with the ionic liquid 1-hexade
J. Braz. Chem. Soc.. Publicado em: 2016-01
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15. Removal of Chromium(VI) from Industrial Effluents Through Supported Liquid Membrane Using Trioctylphosphine Oxide as a Carrier
The present study describes extraction of chromium(VI) through supported liquid membrane (SLM), Celgard 2400, which was impregnated with trioctylphosphine oxide (TOPO) dissolved in toluene. The stripping phase was comprised of diphenylcarbazide (DPC) in sulfuric acid (H2SO4) whereas the feed phase consists of potassium dichromate (K2Cr2O7) and hydrogen perox
J. Braz. Chem. Soc.. Publicado em: 2016-01
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16. Use of Biodiesel Press Cake Waste to Prepare Fe/Carbon Reactive Composites for Environmental Applications: Removal of Hazardous CrVI Contaminants
In this work, Ricinus communis L. press cake waste from biodiesel production was used to produce a versatile reactive material for environmental applications. The biodiesel cake waste was impregnated with FeIII at different concentrations (19-45 wt.%) and treated at 400, 600 and 800 °C. Mössbauer, X-ray diffraction (XRD), thermogravimetric analysis (TG/DTA
J. Braz. Chem. Soc.. Publicado em: 2015-10
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17. Biosorption of Mn (II), Co (II) and Cr (VI) in a horizontal rotating tubular bioreactor: experiments and evaluation of the integral bioprocess model
In this research, a multi heavy metals removal process with mixed microbial culture was examined in a horizontal rotating tubular bioreactor (HRTB) with different combinations of process parameters. Three metals were selected as examples of cations (manganese and cobalt) and oxy-anion (hexavalent chromium). Hydrodynamic conditions and biomass sorption capaci
Braz. J. Chem. Eng.. Publicado em: 2014-09
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18. Characterization and Metal Detoxification Potential of Moderately Thermophilic Bacillus cereus from Geothermal Springs of Himalaya
Two thermophilic Bacillus cereus strains (B. cereus-TA2 and B. cereus-TA4) used in the present study were isolated from the geothermal spring of Hunza valley, Gilgit, Pakistan. They showed the ability to withstand and grow at high temperature (85°C). Both these strains could resist multiple metals (copper, cadmium, mercury, manganese, zinc, arsenic, chromiu
Braz. arch. biol. technol.. Publicado em: 2014-08
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19. Impact of environmental stress on biochemical parameters of bacteria reducing chromium
Chromium pollution is produced in connection with industrial processes like in tanneries. It has been suggested that bioremediation could be a good option for clean up. The stress effect of variable chromate levels, pHs and growth temperatures on biochemical parameters of two Cr(VI) reducing bacterial strains Pseudomonas aeruginosa Rb-1 and Ochrobactrum inte
Braz. J. Microbiol.. Publicado em: 2014-06
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20. Fractionation of aquatic humic substances and dynamic of chromium species in an aquatic body influenced by sugarcane cultivation
Este estudo teve como objetivo principal avaliar a influência das SHA obtidas a partir de uma área de cultivo de cana de açúcar sobre a influência das espécies de crômio (Cr(III) e Cr(VI)). Foi estudada a capacidade de complexação (CC) das SHA com as espécies de crômio e estas foram caracterizadas por espectrofotometria de UV/Vis, fluorescência m
J. Braz. Chem. Soc.. Publicado em: 2014-01
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21. Preparation and evaluation of magnetic chitosan particles modified with ethylenediamine and Fe(III) for the removal of Cr(VI) from aqueous solutions
The adsorption of Cr(VI) in aqueous solution by magnetic particles of crosslinked chitosan-ethylenediamine-Fe(III) (MPCh-EDA-FeCL) was studied in a batch system. Fe3+ in the MPCh-EDA-FeCL permitted that adsorption of Cr(VI) occurred with maximum efficiency between pH 3 and 11. The maximum adsorption capacity at pH 7.0 was 81.04 mg g-1 at 25 ºC. The adsorpti
Quím. Nova. Publicado em: 2014
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22. Punica granatum L. protects mice against hexavalent chromium-induced genotoxicity
Este estudo investigou os efeitos quimioprotetores do extrato alcoólico dos frutos da Punica granatum L. (Punicaceae) (EPG) em camundongos expostos ao cromo hexavalente [Cr(VI)]. Os animais foram pré-tratados com o EPG (25, 50 ou 75 mg/kg/dia) durante 10 dias e subsequentemente expostos a uma dose subletal de Cr(VI) (30 mg/kg). A frequência de eritrócito
Braz. J. Pharm. Sci.. Publicado em: 2013-12
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23. Avaliação por EIE do filme contendo o silano γ-UPS como revestimento de passivação para as ligas ZnFe e ZnCo eletrodepositadas
Pré-tratamentos a base de Cr(VI), têm sido usados há muito tempo em diversos materiais, como eletrodepósitos e ligas de zinco; entretanto, por serem tóxicos para o homem e ao meio ambiente, estão sendo definitivamente banidos, segundo diretrizes européias [2000/53/EC]. Nesse contexto, novas tecnologias alternativas têm sido estudadas e desenvolvidas.
Matéria (Rio J.). Publicado em: 2013-12
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24. Hexavalent chromium reduction by immobilized cells of Bacillus sphaericus AND 303
Bacillus sphaericus AND 303, a Cr(VI)-resistant and reducing bacterium reported from serpentine outcrops of Andaman was evaluated for Cr(VI) reduction using immobilized cells under batch culture. Screening of inert matrices for entrapment of whole cells indicated that polyvinyl alchohol-alginate was the most effective one reducing 87.5% of 20 µM Cr(VI) in 2
Braz. arch. biol. technol.. Publicado em: 2013-06