School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China.
School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China.
J Hazard Mater. 2021 Apr 15;408:124885. doi: 10.1016/j.jhazmat.2020.124885. Epub 2020 Dec 18.
Removal of lead (II) (Pb) from contaminated soil was investigated using a new-type switchable-array-electrode electrokinetics assisted by permeable reactive barrier (SAE/EK-PRB). The soil pH after treatments with SAE/EK-PRB ranged from 3.5 to 4.8, and the peak values of current density was highest with 3.01 mA/cm at voltage gradient 2.5 V/cm. Both voltage gradient and moisture content promoted the removal of Pb. Moisture content 35% and 2.5 V/cm were considered as the optional operating conditions. Different PRB filling materials including zeolite, fly ash, active carbon alone and the combination of fly ash and graphene oxide were, therefore, investigated under the optional operating conditions. The highest removal reached 92.6% with the combination of fly ash and graphene oxide. Pb forms in the soil with different PRB filling materials showed the percentages of weak bindings, such as exchangeable and carbonate forms decreased. However, strong binding, residual form increased largely, indicating the SAE/EK-PRB could effectively reduce the environmental risk of Pb to a great extent. Fly ash and the combination of zeolite and fly ash as PRB filling materials demonstrated to be highly promising for the effective EK remediation of Pb-contaminated soil, taking the economic and environmental principles and remediation efficiency into consideration.
采用新型可切换阵列电极电动强化可渗透反应屏障（SAE/EK-PRB）技术去除污染土壤中的铅（II）（Pb）。经 SAE/EK-PRB 处理后，土壤的 pH 值在 3.5 到 4.8 之间，在 2.5 V/cm 的电压梯度下，电流密度的峰值最高可达 3.01 mA/cm。电压梯度和水分含量均促进了 Pb 的去除。35%的水分含量和 2.5 V/cm 的电压梯度被认为是可选的操作条件。在可选的操作条件下，研究了不同的 PRB 填充材料，包括单独的沸石、粉煤灰、活性炭以及粉煤灰和氧化石墨烯的组合。因此，采用粉煤灰和氧化石墨烯的组合，Pb 的去除率最高可达 92.6%。用不同 PRB 填充材料形成的土壤中的 Pb 表现出较弱结合的百分比，如可交换和碳酸盐形式减少。然而，强结合的残余形式大大增加，表明 SAE/EK-PRB 可以在很大程度上有效降低 Pb 的环境风险。考虑到经济和环境原则以及修复效率，粉煤灰和沸石与粉煤灰的组合作为 PRB 填充材料，被证明对受 Pb 污染的土壤进行有效的 EK 修复具有很大的潜力。
