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00000cam a2200000Ka 4500 |
| 001 |
in00002036639 |
| 005 |
20151101052759.0 |
| 006 |
m f d |
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cr unu|||||||| |
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050302s2003 txu obm 000 0 eng d |
| 035 |
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|a (OCoLC)ocm57937338
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| 035 |
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|a (TxCM)etd-tamu-2003B-2003070614-AHN
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| 035 |
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|a (OCoLC)57937338
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| 040 |
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|a TXA
|c TXA
|d OCLCQ
|d TXA
|d UtOrBLW
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| 049 |
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|a TXAM
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| 099 |
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|a 2003
|a Thesis
|a A346
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| 100 |
1 |
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|a Ahn, Min,
|d 1969-
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| 245 |
1 |
0 |
|a Remediation of chromium(VI) in the vadose zone :
|b stoichiometry and kinetics of chromium(VI) reduction by sulfur dioxide /
|c by Min Ahn.
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| 264 |
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|a [College Station, Tex.] :
|b [Texas A & M University],
|c [2003]
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| 300 |
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|a 1 online resource.
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| 336 |
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|a text
|b txt
|2 rdacontent
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| 337 |
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|a computer
|b c
|2 rdamedia
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| 338 |
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|a online resource
|b cr
|2 rdacarrier
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| 500 |
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|a Vita.
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| 500 |
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|a Abstract.
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| 500 |
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|a "Major Subject: Civil Engineering"
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| 500 |
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|a Title from author supplied metadata (automated record created on Oct. 15, 2004.)
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| 502 |
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|b M.S.
|c Texas A & M University
|d 2003.
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|a Includes bibliographical references.
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| 516 |
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|a Text (Thesis).
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3 |
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|a 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.
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| 538 |
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|a System requirements: Adobe Acrobat Reader.
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| 500 |
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|a Electronic resource.
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| 650 |
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4 |
|a Major civil engineering.
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| 653 |
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|a chromium
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| 653 |
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|a sulfur dioxide
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| 653 |
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|a remediation
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| 653 |
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|a kinetics
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| 653 |
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|a immobilization
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| 700 |
1 |
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|a Batchelor, Bill,
|e thesis advisor.
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| 856 |
4 |
0 |
|u http://hdl.handle.net/1969.1/1183
|z Link to OAK Trust copy
|t 0
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| 948 |
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|a cataloged
|b h
|c 2005/3/10
|d o
|e bsurratt
|f 2:24:43 pm
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| 949 |
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|a updated
|b h
|c 2012/9/6
|e mwilson
|f 12:17:48 pm
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| 994 |
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|a C0
|b TXA
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| 999 |
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|a MARS
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| 999 |
f |
f |
|s 19ffe3b9-de47-3407-81ea-51d61162c176
|i 8a528a2a-d2c5-3b46-a901-14c6f1867c88
|t 0
|
| 952 |
f |
f |
|a Texas A&M University
|b College Station
|c Electronic Resources
|d Available Online
|t 0
|e 2003 Thesis A346
|g Electronic
|h Other scheme
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| 998 |
f |
f |
|a 2003 Thesis A346
|t 0
|l Available Online
|