中文摘要：

通过吸附-解吸试验分别研究了壳聚糖和EDTA对污染棕红壤土中Pb的解吸作用。结果表明，壳聚糖螫合剂及EDTA均能显著提高棕红壤中吸附态铅的解吸效率，增加解吸溶液中Pb的浓度。壳聚糖对污染土壤中Pb的解吸作用随着壳聚糖加入量的增大而增大，在达到一定浓度时提取率达到最高值，最后趋向平缓，而提取液pH值的变化对提取率影响较小；EDTA的提取率随其加入量增大而增加，然后趋缓，而提取液pH的增加提取率则呈先下降后上升的趋势，在pH为3时最低。壳聚糖与EDTA比较而言．两者的提取率比较接近。

英文摘要：

Soils are a major sink for lead （Pb）, which can be absorbed and bioaccumulated by plants and animals and eventually consumed by humans. Phytoremediation, the use of plants to remove or stabilize contaminants, is an inexpensive technique that can be applied to large areas for both remediation and the prevention of soil erosion. However, the low soluhility of most lead compounds rarely results in Pb hyperaccumulation in plant. The use of chemical agents to increase metal desorption and solubility from soil has been a helpful tool to enhance metal uptake by plants. The objective of this study is to examine the role of ethylenediaminetetracetic acid （EDTA） or Chitosan in Pb desorption from soil at various experimental conditions. The results showed that the portion of lead desorbed from soil increased with an increasing concentration of EDTA or Chitosan. The effects of solution pH value to desorption level were obvious, especially the portions of lead desorbed from soil （33% for EDTA, and 62% for chitosan） were higher at very acid conditions （pH was 2）. The results show compared with EDTA, Chitosan was a natural macromolecule organic compound, and harmless to the plant and soil, therefore chitosan was a new available chelate for phytoremediation on Pb contamination soil.