甘氨酸-β-环糊精对土壤中铅的增溶、解吸行为研究

Enhanced Solubilization and Desorption Behavior of Lead in Soil with Glycine-β-cyclodextrin

为改善β-环糊精(β-CD)的水溶性及对重金属的配位能力,将β-环糊精和甘氨酸在碱性条件下用环氧氯丙烷连接起来,合成水溶性极好并能跟重金属形成配位作用的甘氨酸-β-环糊精(GCD),研究了GCD对铅的增溶、解吸行为,考察了pH、离子强度、有机质和甘氨酸-β-环糊精初始浓度对铅的解吸影响。结果表明,GCD对碳酸铅的增溶效果显著,当其浓度为30g.L-1时,水溶液中铅离子浓度可接近7000mg.L-1。GCD对铅解吸能力随着土壤中有机质含量的增加而降低,pH值的升高、离子强度的增加和GCD初始浓度增加有利于铅的解吸。GCD对铅污染土壤的解吸符合准二级动力学模式,该静态解吸研究可以为铅污染土壤的修复提供基础信息。

Glycine-β-cyclodextrin（GCD） with high water solubility and coordination ability for heavy metal was synthesized by the reaction of β-cyclodextrin with glycine under basic condition with epichlorohydrin used as the cross-linking agent.The effects of obtained GCD on enhanced solubilization and desorption behavior of lead in soil was studied,the influence factors of lead desorption,such as pH,ionic strength,organic matter content and initial concentration of GCD,were also investigated and described in details.The results showed that GCD had obvious solubilization for lead carbonate,when the concentration of GCD reached 30 g·L-1,the aqueous lead concentration was about 7 000 mg·L-1.A high organic matter content in soil resulted in a lower desorption efficiency of GCD for lead in soil,and the desorption efficiency of lead increased with increasing pH,ionic strength and initial concentration of GCD.The data of lead desorption in soil were well fitted by the pseudo-second-order rate equation.This static desorption research provided some fundamental information for the remediation of lead contaminated soil.