| 甘肃白银东大沟铅锌镉复合污染场地水泥固化稳定化原位修复 |
| 摘要点击 2982 全文点击 1208 投稿时间：2017-03-02 修订日期：2017-04-09 |
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| 中文关键词 重金属 水泥 固化稳定化 浸出毒性 微观分析 |
| 英文关键词 heavy metal cement solidification/stabilization leaching toxicity microscopic analysis |
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| 中文摘要 |
| 以甘肃白银东大沟Pb、Zn、Cd复合污染土壤为研究对象，通过毒性浸出、形态提取、微观分析等手段，研究了水泥对重金属污染场地的固化稳定化效果及适用性.毒性浸出结果表明，水泥对污染土壤中Cd、Zn能够起到较好的固化稳定化作用，在5%的添加量下，水泥对Cd、Zn的修复效率分别达到99.5%~100%、96.6%~98.8%，而Pb的浸出浓度提高了2.6~5.8倍；在8%的添加量下，水泥对Cd、Zn的修复效率分别达到99.6%~100%，94.4%~97.9%，而Pb的浸出浓度提高了1.9~12.5倍.形态分析结果表明，水泥能够使土壤中的酸可提取态Cd、Zn向残渣态转化，可还原态Pb向可氧化态、残渣态转化，稳定性增强.微观特征分析结果表明，Pb2+、Zn2+、Cd2+这3种离子可以参与水泥的水化反应，生成相应的硅酸盐矿物和氢氧化物，进而对其起到固化稳定化作用.综上，水泥在重金属污染场地修复工程中具有良好的优势，但在具体应用过程中需注意场地及环境条件的特殊性. |
| 英文摘要 |
| In order to evaluate the effects and mechanism of in-situ cement solidification/stabilization (S/S) on heavy metal contaminated soils, leaching tests, speciation analysis, and microscopic analysis were conducted after cement treatment of a Pb, Zn, and Cd contaminated site in Baiyin, China. The leaching test results showed that cement could effectively stabilize Cd and Zn, which could reduce 99.5%-100% and 96.6%-98.8% of H2SO4-HNO3 extractable Cd and Zn, respectively. However, the leaching concentration of Pb was 2.6-5.8 times higher than that before 5% cement treatment. After adding 8% cement, H2SO4-HNO3 extractable Cd and Zn were reduced by 99.6%-100% and 94.4%-97.9% respectively. Similarly, the leaching concentration of Pb was 1.9-12.5 times higher than that before 8% cement treatment. The results of sequential extraction test proposed by the European Community Bureau of Reference (BCR) showed that cement could transform acid extractable Cd and Zn to residual form and transform reducible fractions of Pb to oxidizable and residual form, increasing the stability of heavy metals in soil. The microscopic analysis results showed that Pb2+, Zn2+, and Cd2+ could participate in the process of cement hydration and form silicate minerals and hydroxides. In conclusion, cement could be an effective S/S agent to remediate heavy metal contaminated soils, and site characteristics and environmental conditions should also be considered during the construction process. |
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