基于EKG电动脱水去除稻田土壤 重金属Cd的试验研究

为研究基于EKG电动脱水去除稻田土壤重金属镉(Cd)的效果,进行了土壤淋洗-电动脱水室内模拟试验,重点考察了FeCl₃淋洗后在不同电压梯度(1,2,3,4,5 V/cm)和不同电极间距(20, 30, 40, 50 cm)下,土壤各截面pH值的变化特点和电动脱水去除土壤Cd的效果。结果表明:电动脱水前后土壤各截面pH值均在2.2~2.5之间波动;土壤Cd的电动脱除率随电压梯度增大而增大,随电极间距增大而减小,脱除率最大可达47%;单位电动脱除率的能耗均与电压梯度和电极间距的大小呈正相关。试验结果说明以EKG为电极材料进行电动脱水,能有效地控制土壤各截面pH值,促进土壤孔隙水中可移动态Cd的高效脱除。

Removing Cd from Paddy Field Soil with Electric Dehydration Based on Electrokinetic Geotextile

To investigate the rate of removing heavy metal Cd from paddy field soil with electric dehydration based on Electrokinetic geotextile (EKG), a leaching-electric dehydration laboratory simulation experiment was conducted. The variations of pH value of soil and the removal rate of Cd were inspected under different voltage gradients (1,2,3,4,5 V/cm) and electrode spacings (20, 30, 40, 50 cm) after leaching with FeCl₃. Results show that during the electric repair, the pH value of soil fluctuated between 2.2-2.5; the electric removal rate of Cd in soil increased with the climbing of voltage gradient, while decreased with the expansion of electrode spacing, and the removal rate was up to 47%; moreover, the energy consumption per unit of electric removal rate is positively correlated with the voltage gradient and the electrode spacing. The research finding demonstrates that electrokinetic dehydration with EKG as electrode material could control the pH value of soil effectively and promote the efficient removal of movable Cd in pore water of soil.