Trivalent Chromium
Mostrando 1-12 de 25 artigos, teses e dissertações.
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1. Hybrid Materials Based on Bentonite Functionalized with Amine Groups via the Hydrolytic Sol-Gel Method
Bentonite is a natural clay that presents characteristics such as good capacity to exchange cations, large specific surface area, large porosity, and possibility to undergo intercalation and/or functionalization. This work reports on bentonite functionalization with organomodified alkoxides. Functionalization afforded hybrid materials displaying desirable pr
J. Braz. Chem. Soc.. Publicado em: 2016-05
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2. Corrosion protection in sulfate medium by self-assemb films adsorbed on AA 2024 T3 aluminum alloy surface
In this study, the corrosion protection provided by films of self-assembled molecules on the AA 2024-T3 aluminum alloy has been evaluated by electrochemical and non electrochemical techniques. The film was obtained by immersion of this alloy samples in a solution of 90 mg L-1 alkane-diphosphonate at 50 °C for 5 minutes. Chromating conversion treatment with
Matéria (Rio J.). Publicado em: 2015-06
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3. Influence of chromium concentration on the electron magnetic resonance linewidth of Cr3+ in SrTiO3
Electron magnetic resonance (EMR) spectra of Cr3+ ions in samples of chromium-doped strontium titanate (SrTiO3) have been studied at room temperature for chromium concentrations between 0.20 and 1.00 mol%. According to previous studies, chromium substitutes Ti4+ sites in the lattice and its preferred valence state is Cr4+, which is EMR silent in the X-band,
Materials Research. Publicado em: 31/05/2012
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4. Dinâmica do cromo em solos fertilizados com proteína hidrolisada de couro / Dynamics of chromium in soil fertilized with leather hydrolysate
This study intends to subsidize the decision for utilizing leather hidrolysate as fertilizer in the state of Rio Grande do Sul. The distribution and potential mobility of chromium in different soils, applied in increasing amounts of leather hidrolysate were investigated. The analyses involved sequential fractioning procedure and speciation of chromium, in ad
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2012
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5. Propriedades ópticas, magnéticas e estruturais de monocristais Cs2NaAlF6 dopados com cromo trivalente / Optical, magnetic and structural properties of Cs2NaAlF6 single crystals doped with trivalent chromium
This work is devoted to study the optical, magnetic and structural properties of the elpasolite crystal Cs2NaAlF6 with 0.1, 1.0, 3.0, 10.0, 30.0 and 50.0% of Cr3+ ions. The interest on this material lies on the fact that such system presents a broad, intense band in the visible and infrared regions at room temperature and therefore can be used as a tunable r
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/08/2011
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6. Caracterização da resistência à corrosão de ligas de alumínio após tratamentos alternativos à cromatização, com e sem revestimento orgânico / Characterization of the corrosion resistance of aluminum alloys after alternative treatmentes the chromate, with and without organic coating
In this study, the protective properties provided by new surface treatments for aluminum aiming the replacement of treatments that are harmful to the environment and human health, have been evaluated. The following treatments were investigated: passivation in solution with trivalent chromium ions, surface modification with self assembling molecules (SAM), im
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/03/2011
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7. 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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8. Influence of chromium salts on increased lipid peroxidation and differential pattern in antioxidant metabolism in Pistia stratiotes L
In this work, the changing effect of different concentrations (0, 0.01, 0.1, 1, 10mM) of hexavalent and trivalent chromium on different biochemical parameters along with antioxidant enzymes was investigated on water lettuce (Pistia stratiotes L.) in order to know the possible involvement of this metal in oxidative injury, besides the activities of antioxidan
Brazilian Archives of Biology and Technology. Publicado em: 2010-10
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9. Hexavalent chromium detoxification by living aquatic macrophites root-based biosorption using high resolution x-ray fluorescence / Estudo da reduÃÃo de Cr(VI) usando espÃcies de macrÃfitas aquÃticas vivas pela tÃcnica de fluorescÃncia de raios-X de alta resoluÃÃo
Neste trabalho foi feito o experimento de bioacumulaÃÃo do cromo trivalente e hexavalente por trÃs espÃcies de macrÃfitas aquÃticas: Salvinia auriculata, Pistia stratiotes e Eicchornia crassipes, visando verificar a ocorrÃncia do processo de reduÃÃo do Cr(VI) durante a biossorÃÃo. Previamente, um teste de especiaÃÃo de cromo baseado em extraÃÃ
Publicado em: 2008
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10. SÍNTESE E CARACTERIZAÇÃO DE ÓXIDOS COM BAIXA EXPANSÃO TÉRMICA / SYNTHESIS AND CHARACTERIZATION OF LOW THERMAL EXPANSION OXIDES
Negative and low thermal expansion materials have important potential applications as resistance to thermal shock, as well as, for odontological applications, printed circuit boards, optical components and to produce composites to compensate the positive thermal expansion of materials. For this reason, the study and production of materials with controlled th
Publicado em: 2007
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11. A novel method for fast enrichment and monitoring of hexavalent and trivalent chromium at the ppt level with modified silica MCM-41 and its determination by inductively coupled plasma optical emission spectrometry
Chromium(III) at the ng L-1 level was extracted using partially silylated MCM-41 modified by a tetraazamacrocyclic compound (TAMC) and determined by inductively coupled plasma optical emision spectrometry (ICP OES). The extraction time and efficiency, pH and flow rate, type and minimum amount of stripping acid, and break- through volume were investigated. Th
Química Nova. Publicado em: 2006-06
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12. O impacto do crômio nos sistemas biológicos
The impact of biological chromium's activity may be beneficial or not. This review presents the most relevant chemical aspects of these "two faces" of chromium by covering first, the efforts toward a clearer understanding of the carcinogenic properties of chromium compounds. The biomimetic chemistry of Cr(V) complexes illustrates the interactions of the inte
Química Nova. Publicado em: 2002-07