School of Environment and State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing, 100084, China; National Engineering Laboratory for Site Remediation Technologies, Beijing, 100015, China.
Department of Civil Engineering, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
Chemosphere. 2020 Jul;250:126209. doi: 10.1016/j.chemosphere.2020.126209. Epub 2020 Feb 18.
To address the challenge of trichloroethene (TCE) remediation in low permeability zone, an inexpensive Cu-Ni bimetallic cathode was proposed in electrokinetic (EK) remediation system to couple electrokinetic migration with in situ electrochemical hydrodechlorination. Aqueous phase TCE was originally added into the anolyte so that breakthrough curves through the low permeability porous soil compartment could be obtained to better understand TCE migration driven by electroosmosis flow using different cathodes. The Cu-Ni cathode resulted in more TCE migration of 7.64 mg compared to that of 5.99 mg with Ni and 4.22 mg with mixed metal oxide (MMO) cathode, suggesting that the Cu-Ni cathode was capable of driving more TCE flux out of the contaminated soil. With the Cu-Ni cathode, 98.4% of TCE flux that reached the cathode was electrochemically reduced on the cathode, which was much higher than that with MMO cathode (77.9%) or Ni cathode (59.6%). TCE mass that was transported by electroosmosis flow increased from 2.04 to 6.68 mg when the voltage gradient increased from 1 to 4 V cm, with the normalized energy consumption increasing from 0.06 to 0.16 kWh kg per unit water movement, and from 0.54 to 2.55 kWh g per unit TCE transport. For TCE that did reach the cathode compartment, > 98% degradation maintained at the Cu-Ni cathode with various voltage gradients. The coupled electrokinetic and electrochemical hydrodechlorination technology appears to be a promising strategy for the remediation of low permeability porous media.
为了解决低渗透区三氯乙烯（TCE）修复的挑战，在电动（EK）修复系统中提出了一种廉价的 Cu-Ni 双金属阴极，以将电动迁移与原位电化学加氢脱氯相结合。最初将水相 TCE 添加到阳极电解液中，以便通过低渗透率多孔土壤隔室获得突破曲线，从而更好地理解电渗流驱动的 TCE 迁移，使用不同的阴极。Cu-Ni 阴极导致 7.64mg 的 TCE 迁移量比 Ni 阴极的 5.99mg 和混合金属氧化物（MMO）阴极的 4.22mg 更多，表明 Cu-Ni 阴极能够将更多的 TCE 通量从污染土壤中驱出。在 Cu-Ni 阴极的作用下，到达阴极的 98.4%的 TCE 通量在阴极上被电化学还原，这远高于 MMO 阴极（77.9%）或 Ni 阴极（59.6%）。当电压梯度从 1V/cm 增加到 4V/cm 时，电渗流输送的 TCE 质量从 2.04mg 增加到 6.68mg，归一化能耗从每单位水运动 0.06kWh/kg 增加到 0.16kWh/kg，从每单位 TCE 输送 0.54kWh/g 增加到 2.55kWh/g。对于到达阴极隔室的 TCE，在各种电压梯度下，在 Cu-Ni 阴极上保持了>98%的降解。电动和电化学加氢脱氯相结合的技术似乎是修复低渗透多孔介质的一种很有前途的策略。
