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| Potassium permanganate oxidation-electrokinetic advanced remediation for soils contaminated with trivalent chromium |
| Received:October 21, 2017 |
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| KeyWord:potassium permanganate(KMnO4);oxidation;electrokinetic remediation;trivalent chromium;soil |
| Author Name | Affiliation | | MENG Fan-sheng | Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | NIE Lan-yu | Rizhao Municipal Environmental Protection Bureau, Rizhao 276826, China | | XUE Hao | Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | ZHANG Dao-ping | Chinese Research Academy of Environmental Sciences, Beijing 100012, China |
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| Abstract: |
| The proportion of trivalent chromium[Cr(Ⅲ)] is higher in soils contaminated with chromium residues. The potassium permanganate(KMnO4) oxidation-electrokinetic advanced remediation method was proposed as a means to overcome the low Cr(Ⅲ) removal efficiency of the conventional electrokinetic method for the remediation of chromium-contaminated soil. A voltage of 1 V·cm-1 DC was applied together with the addition of KMnO4 into the cathode for the advanced remediation of simulated Cr(Ⅲ)-contaminated Kaolin as well as chromium residue-contaminated soils collected from a chemical factory in China. Experiments were run for 96 hours. The total chromium[Cr(T)] removal efficiency was significantly enhanced by the(KMnO4) oxidation-electrokinetic advanced remediation method, and the Cr(T) removal rate of the groups with KMnO4 oxidation was up to 78.4% and 42.6%, as compared with 32.4% and 20.9% for the control groups without KMnO4 oxidation, for the simulated Cr(Ⅲ)-contaminated Kaolin(32.4%) and chromium residue-contaminated soils, respectively. The Cr(T) removal rate enhancement increased with the increasing KMnO4 concentration. Under the direct electric field, the MnO-4 added in the cathode moved toward the anode, and the Cr(Ⅲ) positive ions migrated toward the cathode through the soils; some Cr(Ⅲ) ions were adsorbed on the soils by precipitation during migration. The other Cr(Ⅲ) ions were oxidized to hexavalent chromium[Cr(Ⅵ)] ions during KMnO4 migration, and the Cr(Ⅵ) negative ion migrated toward to the anode. Because the migration rate of Cr(Ⅵ) ions was higher than that of Cr(Ⅲ) ions in the soils, the precipitation of Cr(Ⅲ) ions could be controlled effectively, and the chromium removal efficiency could be improved. |
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