【作者】 吴婵；

【导师】 陆晓华；

【作者基本信息】 华中科技大学 ， 环境科学， 2007， 硕士

【摘要】 土壤污染具有隐蔽性、潜伏性和不可逆性等特点,因此,土壤污染一般极难恢复或治理。重金属是最为重要的一类土壤污染物。本文首先介绍了污染土壤修复技术现状,以镉污染土壤为对象,研究了不同条件对土壤中镉解吸行为的影响,污染土壤中镉的电动力学迁移效果,并以铁屑和活性炭构成原电池对土壤中镉进行了电动力学迁移的可行性研究。论文的主要结论包括:(1)镉的解吸效果随着pH值的减小和离子强度的增加而增加。当pH小于4.8时,随着pH的增加,镉的解吸率迅速减小。有机酸的加入能够促进土壤中镉的解吸行为。EDTA能够较大的提高土壤中镉的解吸效果,而柠檬酸对镉的解吸效果影响很小。(2)污染土壤中镉的电动力学迁移效果随施加电压的增加而增加。镉的迁移效果受pH的影响较大,较低的pH产生较为明显的迁移效果。(3)利用铁屑和活性碳构建原电池产生电场驱动土壤中镉的电动力学迁移是可行的。不同电极间距(10 cm,20 cm,30 cm)处理结果表明,镉的迁移效果随电极间距的增加而显著降低。10 cm电极间距土壤中镉的去除率达77.93%,50 cm的电极间距下镉的迁移作用很小。阴极室加入酸性冲洗液如盐酸溶液,柠檬酸溶液等有助于电压的提高,阴极室加入EDTA对镉的迁移效果影响不大。更多还原

【Abstract】 Soil pollution is lagging, dormant and irreversible, therefore, soil pollution is usually difficult to be remedied and treated. Heavy metal is a kind of important soil pollutant. This paper reviewed the soil remediation technology firstly, used cadmium as a representative heavy metal pollutant, investigated the effect of different factors on desorptions of cadmium, and investigated the electrikinetic movement of cadmium with different conditions. The feasibility of the process to restore Cd-comtaminated soil by an iron (Fe) and carbon (C) primary cell is studied also. The main conclusions of this thesis are as follows:(1) The desorption of cadmium increased with the decline of pH and the increase of ionic strength. At pH below 4.8, the desorption of cadmium declinced linearly with the rise of pH. The desorption of cadmium can enhanced by organic acids. EDTA showed excellent enhancement on the desorption of cadmium, however, the desorption of cadmium can not be enhanced by citric acid.(2) In the process to restore Cd-comtaminated soil by electrikinetic, the movement of cadmium was greatly increased with the rise of the electric potential. The movement of cadmium was also related to the value of pH. Low pH also has enhancement on the elecromigration efficiency of cadmium.(3) The processes to restore Cd-comtaminated soil by an iron (Fe) and carbon (C) primary cell were feasible. A primary cell, with different distances of electrodes, 10 cm, 20 cm, 30 cm and 50 cm respectively, were used to restore Cd-comtaminated soil. The results indicated that the eletromigration efficiencies of Cd declined with the increase of distance. And the eletromigration efficiency was up to 77.93% when the distance of electrodes was 10cm but negligible when the distance of electrodes was 50 cm. The addition of acid eg.HCl and citric acid to cathode compartment could increase the electric potential. The addition of EDTA to cathode compartment had negligible enhancement on the eletromigration efficience of cadmium.更多还原