College of Geo-exploration Science and Technology, Jilin University, Changchun 130026, China.
Anal Methods. 2021 Mar 14;13(10):1269-1277. doi: 10.1039/d0ay01978j. Epub 2021 Feb 24.
Chemical leaching, an emerging technology for treating heavy metal-polluted soils, requires a design for reasonable and new eluent and an evaluation of its efficiency on the simultaneous removal of different elements. In this study, the leaching effect and biodegradability of chelating agents were compared, and ethylenediamine disuccinic acid (EDDS) was selected to combine with ferric chloride (FeCl) for the design of a mixed eluent (EDDS + FeCl). Through batch experiments, the influences of the eluent concentration and solution pH on leaching were revealed, and leaching efficiencies of EDDS, FeCl, and EDDS + FeCl on six heavy metals Cd, Cr, Pb, Cu, Ni, and Zn in the soil were separately analyzed. Results indicated that EDDS + FeCl showed advantages over both EDDS and FeCl alone, and it presented an excellent effect, especially for simultaneously leaching multiple heavy metals from the soil. The highest leaching efficiencies for Cd, Cr, Pb, Cu, Ni, and Zn reached up to 71.36%, 21.29%, 31.14%, 30.25%, 34.05%, and 4.96%, respectively. According to different soil types and target elements, the concentration, pH condition, and mass ratio of EDDS + FeCl could be adjusted for soil remediation. Fourier transform infrared spectroscopy proved that the better leaching effect of EDDS + FeCl was attributed to changes in the number and strength of functional groups in the solution, which enhanced the chelating ability of the mixed eluent and heavy metal ions. Therefore, chemical leaching by EDDS + FeCl for the remediation of multiple heavy metal-contaminated soil is a potential feasible strategy.
化学淋洗是一种新兴的处理重金属污染土壤的技术，需要设计合理且新颖的淋洗剂，并评估其同时去除不同元素的效率。本研究比较了螯合剂的浸出效果和生物降解性，选择乙二胺二琥珀酸（EDDS）与氯化铁（FeCl）结合，设计混合淋洗剂（EDDS+FeCl）。通过批实验，揭示了淋洗剂浓度和溶液 pH 对浸出的影响，并分别分析了 EDDS、FeCl 和 EDDS+FeCl 对土壤中六种重金属（Cd、Cr、Pb、Cu、Ni 和 Zn）的浸出效率。结果表明，EDDS+FeCl 比 EDDS 和 FeCl 单独使用具有优势，对同时从土壤中浸出多种重金属具有优异的效果。Cd、Cr、Pb、Cu、Ni 和 Zn 的最高浸出效率分别高达 71.36%、21.29%、31.14%、30.25%、34.05%和 4.96%。根据不同的土壤类型和目标元素，可以调整 EDDS+FeCl 的浓度、pH 条件和质量比，以进行土壤修复。傅里叶变换红外光谱证明，EDDS+FeCl 具有更好的浸出效果，这归因于溶液中官能团数量和强度的变化，增强了混合淋洗剂和重金属离子的螯合能力。因此，EDDS+FeCl 化学淋洗修复多种重金属污染土壤是一种潜在可行的策略。
