Author: Dwight Craig Ramdon
Publisher:
ISBN:
Category : Chromium
Languages : en
Pages : 740
Book Description
Kinetics and Mechanisms of the Reactions of Chromium (VI) with Sulfur-containing Compounds in Aqueous Acid Solution
Author: Dwight Craig Ramdon
Publisher:
ISBN:
Category : Chromium
Languages : en
Pages : 740
Book Description
Publisher:
ISBN:
Category : Chromium
Languages : en
Pages : 740
Book Description
Kinetics and Mechanisms of Reactions of Chromium (VI) with Iron (II) Species
Author: James H. Espenson
Publisher:
ISBN:
Category : Chemical kinetics
Languages : en
Pages : 318
Book Description
Publisher:
ISBN:
Category : Chemical kinetics
Languages : en
Pages : 318
Book Description
Equilibrium and Kinetic Studies in Aqueous Acidic Solutions of Chromium (III), Chromium (VI) and Cerium (IV)
Author: James Ying-Peh Tong
Publisher:
ISBN:
Category :
Languages : en
Pages : 520
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 520
Book Description
Studies of Chromium(VI) Reactions with Sulfur-containing Compounds
Author: Muirhead. Katharine Ann Myers
Publisher:
ISBN:
Category :
Languages : en
Pages : 212
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 212
Book Description
Remediation of Chromium(VI) in the Vadose Zone
Author: Min Ahn
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Immobilization and detoxification of chromium in the vadose zone is made possible by the existence of an effective reductant, SO2, that exists in a gaseous form at room temperature. Experimental studies were designed to characterize stoichiometry and kinetics of chromium reduction both in aqueous solutions at pH values near neutrality and in soil. First, batch experiments and elemental analyses were conducted to characterize the stoichiometry and kinetics of Cr(VI) reduction in water. The stoichiometric ratio of S(IV) removed to Cr(VI) removed ranged between 1.6 and 1.8. The overall reaction is believed to be the result of a linear combination of two reactions in which dithionate is an intermediate and sulfate is the stable oxidized product. The reaction was also rapid, with the half-time of about 45 minutes at pH 6 and about 16 hours at pH 7. A two-step kinetic model was developed to describe changes in concentrations of Cr(VI), S(IV), and S(V). Nonlinear regression was applied to obtain the kinetic parameters. The rate of reaction was assumed to be second-order with respect to [Cr(VI)] and first-order with respect to [S(IV)], and [S(V)]. The values for the rate coefficient for the first reaction (k1) were found to be 4.5 ("10%), 0.25 ("9.4%) (mM-2h-1) at pH 6 and 7, respectively. The values of the rate coefficient for the second reaction (k2) were 25 ("29%), 1.1 ("30%) (mM-2h-1) at pH 6 and 7, respectively. The reaction rate decreased as pH increased. Experiments showed that the rate at pH 7 was lower than that at pH 6 by one order of magnitude. Second, batch experiments and elemental analyses were conducted to characterize the stoichiometry and kinetics of Cr(VI) reduction in soil. The stoichiometric ratio of S(IV) removed to Cr(VI) removed was almost 2, which is slightly higher than that for the reaction in water. This higher value may be due to S(IV) oxidation by soil-derived Fe(III). The reaction was rapid, with the half-time less than 2 minutes, which is faster than in water. The rate coefficients, k1 and k2, were 22 ("41%) and 13 ("77%) (M-2h-1), respectively.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Immobilization and detoxification of chromium in the vadose zone is made possible by the existence of an effective reductant, SO2, that exists in a gaseous form at room temperature. Experimental studies were designed to characterize stoichiometry and kinetics of chromium reduction both in aqueous solutions at pH values near neutrality and in soil. First, batch experiments and elemental analyses were conducted to characterize the stoichiometry and kinetics of Cr(VI) reduction in water. The stoichiometric ratio of S(IV) removed to Cr(VI) removed ranged between 1.6 and 1.8. The overall reaction is believed to be the result of a linear combination of two reactions in which dithionate is an intermediate and sulfate is the stable oxidized product. The reaction was also rapid, with the half-time of about 45 minutes at pH 6 and about 16 hours at pH 7. A two-step kinetic model was developed to describe changes in concentrations of Cr(VI), S(IV), and S(V). Nonlinear regression was applied to obtain the kinetic parameters. The rate of reaction was assumed to be second-order with respect to [Cr(VI)] and first-order with respect to [S(IV)], and [S(V)]. The values for the rate coefficient for the first reaction (k1) were found to be 4.5 ("10%), 0.25 ("9.4%) (mM-2h-1) at pH 6 and 7, respectively. The values of the rate coefficient for the second reaction (k2) were 25 ("29%), 1.1 ("30%) (mM-2h-1) at pH 6 and 7, respectively. The reaction rate decreased as pH increased. Experiments showed that the rate at pH 7 was lower than that at pH 6 by one order of magnitude. Second, batch experiments and elemental analyses were conducted to characterize the stoichiometry and kinetics of Cr(VI) reduction in soil. The stoichiometric ratio of S(IV) removed to Cr(VI) removed was almost 2, which is slightly higher than that for the reaction in water. This higher value may be due to S(IV) oxidation by soil-derived Fe(III). The reaction was rapid, with the half-time less than 2 minutes, which is faster than in water. The rate coefficients, k1 and k2, were 22 ("41%) and 13 ("77%) (M-2h-1), respectively.
Nuclear Science Abstracts
Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 882
Book Description
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 882
Book Description
Pandex Current Index to Scientific and Technical Literature
Author:
Publisher:
ISBN:
Category : Medicine
Languages : en
Pages : 1318
Book Description
Publisher:
ISBN:
Category : Medicine
Languages : en
Pages : 1318
Book Description
Technical Abstract Bulletin
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 440
Book Description
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 440
Book Description
Dissertation Abstracts International
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 1396
Book Description
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 1396
Book Description
Chromium Reactions in Geologic Materials
Author:
Publisher:
ISBN:
Category : Chromium
Languages : en
Pages : 328
Book Description
Publisher:
ISBN:
Category : Chromium
Languages : en
Pages : 328
Book Description