Purpose

Ethylenediaminetetraacetic acid (EDTA)-enhanced soil washing is an important technique of removing potentially toxic elements (PTEs) from contaminated soils. Conventional mechanical shaking (CMS) method is widely adopted in soil washing. However, it consumes a considerable amount of time and energy. Extraction methods which need less contact time or power, such as static equilibrium extraction (SEE) and ultrasound-assisted extraction (UAE), are potential to replace CMS in industrial application.

Methods

The washing process of the soil from a contaminated site was optimized by investigating various extraction conditions, including EDTA concentration, contact time, and different extraction methods, such as CMS, SEE, and UAE, in this study.

Results

The results indicated that EDTA greatly enhanced the removal of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) from the soil. The EDTA was more effective in removing Pb and Cu than Cd and Zn, regardless of the extraction method. This might be mainly attributed to the strong complexation capacity of EDTA with Pb and Cu and geochemical distribution of the target PTEs. The three extraction methods were almost equally efficient, while SEE required less energy and UAE needed shortened contact time compared with CMS.

Conclusion

Based on the above results, SEE and UAE are promising alternatives to CMS for cleaning up PTEs-contaminated soils.

中文翻译：

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优化萃取程序，以在EDTA辅助土壤洗涤过程中更好地去除潜在的有毒元素

目的

乙二胺四乙酸（EDTA）增强的土壤洗涤是一种从污染土壤中去除潜在有毒元素（PTE）的重要技术。常规机械摇动（CMS）方法被广泛用于土壤洗涤。但是，它消耗了大量的时间和精力。需要更少接触时间或更少功率的萃取方法，例如静态平衡萃取（SEE）和超声辅助萃取（UAE），有可能在工业应用中取代CMS。

方法

在本研究中，通过研究各种萃取条件（包括EDTA浓度，接触时间和不同的萃取方法，如CMS，SEE和UAE），优化了从受污染场所冲洗土壤的过程。

结果

结果表明，EDTA大大提高了土壤中镉（Cd），铜（Cu），铅（Pb）和锌（Zn）的去除。无论采用哪种提取方法，EDTA都比Cd和Zn更有效地去除Pb和Cu。这可能主要归因于EDTA与Pb和Cu的强络合能力以及目标PTE的地球化学分布。与CMS相比，这三种萃取方法几乎具有相同的效率，而SEE所需的能量更少，UAE所需的接触时间更短。

结论

基于以上结果，SEE和阿联酋有望成为CMS的替代品，以清除受PTE污染的土壤。