College of Environmental Sciences and Engineering, Peking University, Beijing Key Laboratory for Solid Waste Utilization and Management, Beijing, 100871, China.
Ecological Environment Consulting Department, Beijing Construction Engineering Environmental Remediation Co., Ltd., Beijing, 100015, China.
J Environ Manage. 2024 Nov;370:122732. doi: 10.1016/j.jenvman.2024.122732. Epub 2024 Oct 5.
Electrokinetic remediation (EKR) has been applied for in-situ removal of Cd from contaminated soil, and the EKR enhanced with polarity reversal has achieved a higher Cd removal efficiency. However, the migration and accumulation mechanisms of Cd in the EKR process have not been investigated. In this paper, the cross-impacts of the voltage gradient, citric acid concentration in the electrolyte, and polarity reversal frequency on the removal efficiency by EKR of Cd and the optimization conditions were investigated. The migration and accumulation mechanisms of Cd were explored by analyzing the changes in electrokinetic process parameters, experimental phenomena, and X-ray diffraction (XRD) analysis. The results showed that the maximum removal efficiency of Cd reached 82.26%. The optimal conditions were determined by fitting the RSM model using the BBD design. In the EKR experiment with polarity reversal, Cd accumulated mainly in the middle part of the soil, attributed to the formation of chemical precipitation focusing area caused by soil pH transition, ion-induced potential gradient well trapping effect (IIPGWTE), or soil compaction induced by water loss. In conclusion, the various parameters have cross-impacts on the EKR of Cd-contaminated soil, and efficient in-situ removal of Cd from the contaminated soil can be achieved by adjusting the parameter conditions.
电动修复（EKR）已被应用于原位去除污染土壤中的 Cd，而极性反转增强的 EKR 则实现了更高的 Cd 去除效率。然而，EKR 过程中 Cd 的迁移和积累机制尚未得到研究。本文通过分析电渗流过程参数、实验现象和 X 射线衍射（XRD）分析的变化，研究了电压梯度、电解质中柠檬酸浓度和反转频率对 EKR 去除 Cd 效率的交叉影响及其优化条件。结果表明，Cd 的最大去除效率达到了 82.26%。采用 BBD 设计拟合 RSM 模型确定了最佳条件。在具有极性反转的 EKR 实验中，Cd 主要积聚在土壤的中部，这归因于土壤 pH 转变引起的化学沉淀聚焦区的形成、离子诱导的势梯度阱效应（IIPGWTE）或因水分流失导致的土壤压实。总之，各种参数对 EKR 去除污染土壤中的 Cd 具有交叉影响，可以通过调整参数条件来实现从污染土壤中高效原位去除 Cd。
