J Air Waste Manag Assoc. 2014 Sep;64(9):1013-20. doi: 10.1080/10962247.2014.917129.
When a contaminated site contains pollutants including both nonvolatile metals and Hg, one single remediation technology may not satisfactorily remove all contaminants. Therefore, in this study, chemical extraction and thermal treatment were combined as a remediation train to remove heavy metals, including Hg, from contaminated soil. A 0.2 M solution of ethylenediamine tetraacetic acid (EDTA) was shown to be the most effective reagent for extraction of considerable amounts of Cu, Pb, and Zn (> 50%). Hg removal was ineffective using 0.2 M EDTA, but thermogravimetric analysis suggested that heating to 550 degrees C with a heating rate of 5 degrees C/min for a duration of 1 hr appeared to be an effective approach for Hg removal. With the employment of thermal treatment, up to 99% of Hg could be removed. However executing thermal treatment prior to chemical extraction reduced the effectiveness of the subsequent EDTA extraction because nonvolatile heavy metals were immobilized in soil aggregates after the 550 degrees C treatment. The remediation train of chemical extraction followed by thermal treatment appears to remediate soils that have been contaminated by many nonvolatile heavy metals and Hg. Implications: A remediation train conjoining two or more techniques has been initialized to remove multiple metals. Better understandings of the impacts of treatment sequences, namely, which technique should be employed first on the soil properties and the decontamination efficiency, are in high demand. This study provides a strategy to remove multiple heavy metals including Hg from a contaminated soil. The interactions between thermal treatment and chemical extraction on repartitioning of heavy metals was revealed. The obtained results could offer an integrating strategy to remediate the soil contaminated with both heavy metals and volatile contaminants.
当污染场地含有包括非挥发性金属和 Hg 在内的污染物时，单一的修复技术可能无法完全去除所有污染物。因此，在本研究中，化学萃取和热处理被结合为一种修复技术，用于从污染土壤中去除重金属，包括 Hg。研究表明，0.2 M 的乙二胺四乙酸（EDTA）溶液是提取大量 Cu、Pb 和 Zn（>50%）的最有效试剂。然而，使用 0.2 M EDTA 对 Hg 的去除效果不佳，但热重分析表明，在 550°C 下以 5°C/min 的升温速率加热 1 小时似乎是去除 Hg 的有效方法。采用热处理，Hg 的去除率高达 99%。然而，在化学萃取之前进行热处理会降低随后 EDTA 萃取的效果，因为非挥发性重金属在 550°C 处理后被固定在土壤团聚体中。化学萃取 followed by 热处理的修复技术似乎可以修复受到多种非挥发性重金属和 Hg 污染的土壤。这表明，一种结合了两种或多种技术的修复技术已经被启动，以去除多种金属。更好地了解处理顺序的影响，即哪种技术应该首先应用于土壤性质和去污效率，是非常需要的。本研究提供了一种从污染土壤中去除多种重金属（包括 Hg）的策略。揭示了热处理和化学萃取对重金属重新分配的相互作用。获得的结果可以为修复同时受到重金属和挥发性污染物污染的土壤提供一种综合策略。
