• Title/Summary/Keyword: VI

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Separation and analysis of Cr(III) and Cr(VI) using 8-hydroxyquinoline complexation of Cr(III) (8-Hydroxyquinoline을 이용한 크롬 3가 및 6가의 분리 및 분석)

  • Lim, Heon-Sung;Lee, Sueg-Geun
    • Analytical Science and Technology
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    • v.20 no.3
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    • pp.246-250
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    • 2007
  • The quantitative determination of chromium(VI) by separation from chromium(III) complex of 8-hydroxyquinoline using solvent extraction has been studied. The reaction conditions for chromium(III) complex of 8-hydroxyquinoline and the solvent extraction of complex were investigated in detail. The chromium(III) complex was extracted with organic solvent (n-hexane) and residual chromium(VI) was determined by ICP-AES in aqueous layer. This technique is quantitative in the pH range of 8-9 and the limitations such as interfering ions were discussed.

A Study for Kinetics and Oxidation Reaction of Substituted Benzyl Alcohols Using Cr(VI)-6-Methylquinoline (Cr(VI)-6-Methylquinoline을 이용한 치환 벤질 알코올류의 산화반응과 속도론에 관한 연구)

  • Park, Young Cho;Kim, Young Sik
    • Applied Chemistry for Engineering
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    • v.26 no.3
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    • pp.372-376
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    • 2015
  • 6-MQCC (Cr(VI)-6-methylquinoline) complex was synthesized by the reaction of 6-methylquinoline with chromium(VI) trioxide in 6 M HCl. The structure was characterized using IR (Infrared Spectroscopy) and ICP (Inductively Coupled Plasma) analysis. The oxidation of benzyl alcohol using 6-MQCC in various solvents showed that the reactivity increased with the increase of the dielectric constant, in descending order of DMF > acetone > chloroform > cyclohexene. In the presence of DMF solvent with acidic catalyst such as sulfuric acid ($H_2SO_4$), 6-MQCC oxidized benzyl alcohol (H) and its derivatives ($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, $m-NO_2$) were effectively oxidized. Electron-donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. The Hammett reaction constant (${\rho}$) was -0.69 (308 K). The observed experimental data was used to rationalize the fact that the hydride ion transfer occurred at the rate-determining step.

Removal of Trichloroethylene, Cr(VI) and Nitrate in Leachate by Bentonite and Zero Valent Iron (벤토나이트와 영가 철에 의한 침출수 내의 Trichloroethylene, Cr(VI), 질산성질소의 제거)

  • Lee, Hyun-Joo;Park, Jae-Woo
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.2
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    • pp.23-31
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    • 2004
  • Trichloroethylene(TCE), Cr(VI), and nitrate removal efficiency of a novel reactive barrier were experimented, and the types of corrosion species that form on the surface of the iron and bentonite as a result of reaction were investigated with Raman spectrophotometer. The reactive barrier is composed of bentonite and zero valent iron(ZVI), and this can substitute conventional geosynthetic clay liners for landfill leachate. Tests were performed in batch reactors for various ZVI content (0, 3, 6, 10, 13, 16, 20, 30, 100 w/w %) and pH. The reduction rates and removal efficiencies of TCE, Cr(VI) and nitrate increase at pH 7 buffered solution. As ZVI content increases, TCE, Cr(VI) and nitrate removal efficiencies increase. From the result of analysis with Raman spectrophotometer, Fe-oxides were observed, which are strong adsorbers of cantaminants. Magnetite can be also beneficial to the long term performance of the iron metal.

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