Qian Jie, Li Ying-Hua, Su Fei, Wu Ji-Guo, Sun Jia-Ru, Huang Tian-Ci
School of Resources and Civil Engineering, Northeastern University, Shenyang, 110004, China.
Environ Sci Pollut Res Int. 2023 Jan;30(1):2118-2127. doi: 10.1007/s11356-022-22287-3. Epub 2022 Aug 5.
In order to solve the problem of soil pollution caused by excess heavy metals, cadmium (Cd), a novel soil-washing agent organic chelating acid-based deep eutectic solvent (OCA-DES), was investigated for the removal of Cd from the contaminated soil of coking plant. Four kinds of OCA-DES were prepared by mixing choline chloride (Ch-Cl) with four organic chelating acids (citric acid, oxalic acid, tartaric acid, and malic acid), respectively, to compare their washing efficiency of Cd from soil. The effects of washing operation conditions on the Cd removal efficiency were investigated. Side effects of citric acid-based deep eutectic solvent (CA-DES) on soil were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). The results showed that CA-DES had the best Cd removal efficiency and could reach as high as 93.75%, under ideal conditions. CA-DES mainly washed extractable and reducible Cd. The CA-DES washing process has less side effects on soil and hardly eroded the soil or changed the mineral structure of the soil. The main roles of CA-DES washing Cd include (1) hydrogen bonds capturing Cd; (2) the carboxyl group(-COOH) forming soluble chelate with Cd; and (3) releasing H ions in exchange for Cd. This study demonstrates that CA-DES, a novel soil-washing agent, has excellent removal of cadmium from soil and is environment-friendly.
为了解决过量重金属导致的土壤污染问题，研究了一种新型土壤清洗剂——基于有机螯合酸的深层共熔溶剂（OCA-DES）对炼焦厂污染土壤中镉（Cd）的去除效果。分别将氯化胆碱（Ch-Cl）与四种有机螯合酸（柠檬酸、草酸、酒石酸和苹果酸）混合制备了四种OCA-DES，以比较它们对土壤中镉的洗脱效率。研究了洗脱操作条件对镉去除效率的影响。利用扫描电子显微镜（SEM）、X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）分析了柠檬酸基深层共熔溶剂（CA-DES）对土壤的副作用。结果表明，在理想条件下，CA-DES的镉去除效率最佳，可达93.75%。CA-DES主要洗脱可提取态和可还原态镉。CA-DES洗脱过程对土壤的副作用较小，几乎不会侵蚀土壤或改变土壤的矿物结构。CA-DES洗脱镉的主要作用包括：（1）氢键捕获镉；（2）羧基（-COOH）与镉形成可溶性螯合物；（3）释放氢离子以交换镉。本研究表明，新型土壤清洗剂CA-DES对土壤镉具有优异的去除效果且环境友好。
