| 摘要: |
| 【目的】探讨碳酸钙对铜、铅、铬复合污染土壤的钝化效果及修复机制。【方法】利用碳酸钙对复合污染土壤中的Cu、Pb和Cr进行钝化处理，以重金属有效态含量的减少对碳酸钙投加量进行优化，并对土壤中Cu、Pb和Cr有效态含量的减少进行动力学模拟；运用改进的BCR分级提取法对土壤中的3种重金属进行形态分析，并对修复后的土壤进行X射线衍射(XRD)分析，初步探讨碳酸钙对复合污染土壤中3种重金属的钝化机制。【结果】碳酸钙投加量为50 g/kg时，其对Cu、Pb和Cr污染土壤的修复效果最佳，此时Cu、Pb和Cr有效态含量减少的动力学符合Elovich方程；钝化28 d后，与空白对照组（未添加CaCO3）相比，Cu、Pb和Cr 3种重金属的可交换态含量分别减少28.2%，31.9%和74.8%，可还原态含量分别增加2.9,2.0和1.3倍，残渣态含量分别增加5.8，2.7和1.3倍，可氧化态含量无明显变化。【结论】碳酸钙对土壤中Cu、Pb、Cr 3种重金属的有效态含量有明显钝化效果,其一方面通过提高土壤pH提升土壤对重金属的吸附性能，促进重金属生成Cu3(OH)2(CO3)2等沉淀；另一方面其直接与重金属生成更难溶的PbCO3等沉淀，促进土壤中重金属的钝化。 |
| 关键词: 重金属污染 土壤修复 形态分析 钝化机制 |
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| 基金项目:国家“863”计划项目“污泥土地利用风险控制综合技术研发与示范(2012AA063608 03)”；国家国际合作专项“污水厂污泥与餐厨垃圾高级厌氧消化技术及应用合作研究（2014DFA91650）” |
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| Remediation of Cu(Ⅱ),Pb(Ⅱ) and Cr(Ⅲ) contaminated soils with CaCO3 |
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MA Rongsheng,CHEN Jie,XIA Peng,et al
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| Abstract: |
| 【Objective】This study investigated the passivation effect and remediation mechanism of CaCO3 on Cu,Pb and Cr contaminated soils.【Method】CaCO3 was added to immobilize heavy metals in contaminated soils.The best CaCO3 dosage was chosen according to the immobilization efficiency,and dynamic simulation of the reduction of Cu,Pb and Cr effective contents in soil was carried out.After amendment of CaCO3,the fractions of heavy metals were measured,and the crystal structure of soil was studied using X-ray diffraction (XRD) technique.【Result】CaCO3 performed the best immobilization effect with the dose of 50 g/kg,and the reduction of Cu,Pb and Cr effective contents followed the Elovich equation.After 28 days’ immobilization,the exchangeable contents of Cu,Pb and Cr were reduced by 28.2%,31.9% and 74.8% compared with the control,the reduction contents increased by 2.9,2.0 and 1.3 times,the residual contents increased by 5.8,2.7 and 1.3 times,while the oxidation contents did not change much.【Conclusion】CaCO3 reduced the effective contents of heavy metals in soil by improving soil pH to improve soil adsorption of heavy metals and promote precipitation of heavy metals,and reacting with heavy metals in soil. |
| Key words: heavy metal pollution soil remediation morphological analysis immobilization mechanism |
