EDTA-ENHANCED ELECTROKINETIC EXTRACTION OF CADMIUM FROM A NATURAL CLAY OF HIGH BUFFER CAPACITY
Electrokinetic extraction of contaminants from soils is a promising in-situ remediation technology. During the process, protons generated at the anode enhance the dissolution of metals into the solution phase. However, development of the low pH environment by the process alone is often difficult for natural soils of high buffer capacities. Enhancement agents are thus being used to promote desorption of heavy metals from soil particle surfaces. In this study, EDTA was used to remove cadmium from a natural clay of high buffer capacity from Shanghai, China. Batch experiments and an electrokinetic extraction experiment were conducted to investigate the effectiveness of EDTA in extracting cadmium from the soil. The results of batch tests indicate that it is practically very difficult to solubilize the cadmium sorbed on soil particle surfaces when the soil pH is above 7.0 without enhancement. With the addition of EDTA, more than 90％ of the sorbed cadmium can be dissolved into solution in the pH range of 2.0-11.0. The results of the electrokinetic experiment indicate that the spiked cadmium was transported towards the anode when the final soil pH was increased to 7.8 at the anode and 11 at the cathode. However, a significant amount of cadmium was accumulated in a narrow zone near the anode after 20 hours of electrokinetic treatment.
electrokinetic eztraction cadmium contamination natural clay buffer capacity EDTA
Ying-Ying GU Albert T.YEUNG Hong-Jiang LI
Department of Civil Engineering, University of Hong Kong, Pokfulam Road, Hong Kong Special Administr ShenZhen Environment Project Service Center, Block 5, No.50, Street One, Honggui Road, Shenzhen 5180
国际会议
International Symposium on Geoenvironmental Engineering(国际环境岩土工程研讨会
杭州
英文
790-795
2009-09-08（万方平台首次上网日期，不代表论文的发表时间）