中文摘要：

在电修复过程中，距离阳极越近，pH越低，氧化还原电位越高，越有利于从土壤颗粒中释出重金属并加速电动力学修复土壤过程。本文采用逼近阳极法以不断缩短两极间距离，增强电修复效果。研究中采用模拟cd污染土壤，在电场强度为1V·cm^-1的条件下验证逼近阳极法的修复效果。结果表明，逼近阳极法能够有效地降低修复过程的能耗。在达到同样修复效果的情况下，其单位体积能耗仅为单阳极法的56％。此外，逼近阳极法还显著增大了土壤中Cd的迁移速率，从而缩短了修复过程所耗时间。在距离阳极5、10、15和20cm处，cd的平均富集速率分别为单阳极法的1．50、2．44、3．72和2．00倍，整体修复耗时仅为传统方法的60％。可见。逼近阳极电动力学修复技术具有极大的优越性，并有着良好的应用前景。

英文摘要：

During the electrokinetic remediation （ER） of heavy metal polluted soil, the soil closer to anode has lower pH value and higher redox potential. Either low pH or high redox is helpful to release heavy metal from soil particles and therefore to accelerate the remediation. So, the ＂approaching anodes＂ technique was developed as a simple way to shorten the distance between the anode and cathode and consequently to enhance the remediation. In this technique, a series of anodes were placed in the soil successively. The anode farthest from the cathode was chosen as working anode at the beginning of remediation. After the soil in the vicinity of the anode was cleaned, the working anode was switched to the next anode nearer to the cathode. During the whole ER process, the working anode was switched in order to reduce the distance between anode with cathode gradually. Synthetic Cd contaminated soils was used to test the feasibility of the approaching anodes tech nique. The results showed that the energy consumption per unit volume was significantly reduced in ER process with approaching anodes, which was only about 56% of that with single anode while achieving the same effect. Besides, Cd migration velocity was largely increased and the whole operating time was accordingly saved. The enrichment velocity of Cd in places of 5, 10, 15 and 20 cm was about 1.50, 2.44, 3.72 and 2.00 times to that with single anode respectively. Thus, this process showed great priority and was quite promising in practical application.