碳酸钙对铜铅铬复合污染土壤的修复机制

发布时间：2018-01-09 13:30

本文关键词：碳酸钙对铜铅铬复合污染土壤的修复机制?　出处：《西北农林科技大学学报(自然科学版)》2017年01期 　论文类型：期刊论文

【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50g/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28d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。
[Abstract]:[Objective] to investigate the calcium carbonate of copper, lead, chromium passivation effect and repair mechanism of contaminated soil. [method] the compound pollution of Cu in soil by using calcium carbonate, Pb and Cr passivation to the available content of heavy metals and reduce the amount of calcium carbonate was optimized, and the soil Cu Pb and Cr, the effective content of reduced dynamic simulation; using BCR classification improved morphological analysis of 3 kinds of heavy metals in soil was extracted, and X ray diffraction of the repaired soil (XRD) analysis, preliminary study on passivation mechanism of calcium carbonate on the 3 kinds of heavy metals in contaminated soils. [results] calcium carbonate dosage is 50g/kg, the Cu, Pb and Cr contaminated soil remediation effect best, at Cu, Pb and Cr reduce the dynamic available content accords with Elovich equation; 28d after passivation, and the blank control group (without CaCO3) compared to Cu, Pb and Cr 3 kinds of exchangeable heavy metals contents were reduced by 28.2%, 31.9% and 74.8%, reducible content increased 2.9,2.0 and 1.3 times, the residual content increased 5.8,2.7 and 1.3 times the oxidizable percentage had no obvious change. [Conclusion] the calcium carbonate in soil Cu, Pb, has obvious passivation effect of available content Cr 3 kinds of heavy metals, on the one hand by improving soil pH to enhance the adsorption properties of the heavy metals, heavy metals promote formation of Cu3 (OH) 2 (CO3) 2 precipitation; on the other hand it directly with the heavy metals into more insoluble PbCO3 precipitation, promoting the passivation of heavy metals in soil.

【作者单位】：同济大学环境科学与工程学院/污染控制与资源化研究国家重点实验室;
【基金】：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)”
【分类号】：X53
【正文快照】： 土壤中的重金属迁移慢,具有残留时间长、隐蔽性强、毒性大等问题,经过植物富集后,会通过食物链对人类健康产生威胁[1]。因此,重金属污染土壤的修复一直是国内外环境科学研究的热点和难点问题。目前,重金属污染土壤修复手段主要包括化学修复、物理修复和生物修复,其中原位化学

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