College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China.
Sci Rep. 2020 Mar 24;10(1):5297. doi: 10.1038/s41598-020-60896-5.
Removal of hexavalent chromium [Cr(VI)] from soils and water has been widely studied for its high toxicity. Although leaching method is viewed as an effective approach to eliminate Cr(VI) and some studies attempted to enhance leaching performance via the external electric field, there is little knowledge about the influential factor in electro-leaching system on Cr(VI) removal performance. In this study, an electro-leaching technology was developed for removing Cr(VI) from groundwater aquifer to comprehensively discuss the correlation between the operational parameters and Cr(VI) removal efficiency. When the applied voltage was 20 V and the initial Cr(VI) concentration was 40 mg/kg, Cr(VI) removal efficiency achieved 99.9% in 120 min in the electro-leaching system, 15% higher than the system without the electric field. Cr(VI) removal efficiencies increased with the voltage demonstrating the significant enhancement of the electro-leaching method in removing Cr(VI). When Cr(VI) concentration climbed to 120 mg/kg, Cr(VI) removal efficiency remained above 85%. The effects of different voltages, Cr(VI) concentrations, pollutant distribution and salt content of leaching solution on the leaching effect were also investigated. Meanwhile, the relationship between the current intensity change and the amount of removed Cr(VI) during the electro-leaching process was first investigated, and the relevant model was fitted. There is a quadratic linear correlation between the amount of current change and the amount of removed Cr(VI). This novel electro-enhanced leaching method can effectively remove Cr(VI) from contaminated groundwater aquifer by enhancing the migration of charged contaminant ions during the leaching process, and it is worthy of further study of heavy metal remediation.
从土壤和水中去除六价铬[Cr(VI)]因其高毒性而得到广泛研究。虽然浸出法被认为是消除 Cr(VI)的有效方法，并且一些研究试图通过外部电场来增强浸出性能，但对于电浸出系统中影响 Cr(VI)去除性能的因素知之甚少。在本研究中，开发了一种电浸出技术，用于从地下含水层中去除 Cr(VI)，以综合讨论操作参数与 Cr(VI)去除效率之间的相关性。当施加的电压为 20 V，初始 Cr(VI)浓度为 40 mg/kg 时，在电浸出系统中，Cr(VI)的去除效率在 120 min 内达到 99.9%，比没有电场的系统高 15%。Cr(VI)去除效率随电压的升高而增加，表明电浸出法在去除 Cr(VI)方面有显著的增强效果。当 Cr(VI)浓度升高到 120 mg/kg 时，Cr(VI)的去除效率仍保持在 85%以上。还研究了不同电压、Cr(VI)浓度、污染物分布和浸出液盐含量对浸出效果的影响。同时，首次研究了电浸出过程中电流强度变化与去除的 Cr(VI)量之间的关系，并对相关模型进行了拟合。电流变化量与去除的 Cr(VI)量之间存在二次线性关系。这种新型的电增强浸出方法可以通过增强浸出过程中带电污染物离子的迁移来有效地去除受污染地下水中的 Cr(VI)，值得进一步研究用于重金属修复。
