| 可渗透反应复合电极法对铬(Ⅵ)污染土壤的电动修复 |
| 摘要点击 4375 全文点击 1392 修订日期：2011-08-05 |
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| 中文关键词 污染土壤 六价铬 电动修复 可渗透反应层 复合电极 |
| 英文关键词 contaminated soil Cr(Ⅵ) electrokinetic remediation permeable reactive layers composite electrodes |
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| 中文摘要 |
| 将Fe0、沸石等活性材料附着在电极上构成可渗透反应复合电极,以Cr(Ⅵ)污染土壤为处理对象,对电动修复过程中可渗透反应复合电极法对土壤pH的控制、Cr的去除效果以及形态变化进行了研究.结果表明,添加可渗透反应材料的复合电极法比单一电极法无论在土壤pH控制还是Cr的去除方面都有明显的改善和提高,其中以在阳极同时添加Fe0和沸石效果最为显著.在施加2 V·cm-1的直流电压,运行5 d后,相比在阳极单纯添加沸石或Fe0可渗透反应层,添加"Fe0+沸石"反应层能在最大程度上减小阳极土壤pH值的波动,可将土壤pH值控制在5.5~8.5范围内,土壤中任意位置Cr(Ⅵ)的去除率可提高到97%以上,土壤中残留的Cr(Ⅲ)更少,可渗透反应层对Cr的截留量可分别提高8倍和1.8倍,并将98%的Cr(Ⅵ)转化为低毒的Cr(Ⅲ).研究结果为开发具有实用意义的可渗透反应复合电极修复技术提供了理论依据. |
| 英文摘要 |
| Electrokinetic transport processes have been shown to have potential for the effective removal of heavy metals from soils. However, pH changes near the anode and cathode limit their widespread application in the remediation of contaminated soils. Permeable reactive composite electrodes (PRCE) were made by attaching reactive materials such as Fe0 and zeolite to the electrodes, and the effects of the composite electrodes on pH control, chromium removal efficiency and Cr speciation changes were studied in the electrokinetic remediation process of Cr(Ⅵ) contaminated soil. Composite electrodes consisting of permeable reactive materials gave better pH control and Cr removal efficiency compared to traditional electrodes, and a Fe0+zeolite reactive layer in the anode exhibited the best performance compared to zeolite or Fe0 alone. After 5 days of electrokinetic remediation with a DC voltage of 2 V·cm-1, the Fe0+zeolite reactive layer lowered the pH fluctuation, maintained the soil pH in the range of 5.5 to 8.5, raised the Cr(Ⅵ) removal efficiency up to 97% in any soil section, produced lower Cr(Ⅲ) residues, enhanced the amount of Cr retention up to 8 and 1.8 times respectively, and transformed 98% of the Cr(Ⅵ) into lower toxicity Cr(Ⅲ). This study provides a theoretical basis for the exploitation of permeable reactive composite electrodes which are a practical option for future applications. |
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