水溶性羧甲基壳聚糖对Cd2+的解吸行为研究

为改善壳聚糖(CTS)的水溶性及对重金属的配位能力,合成水溶性好并能与重金属形成配位作用的水溶性羧甲基壳聚糖(WSCC),研究了WSCC对镉的增溶、解吸行为,考察了pH、离子强度、有机质含量和WSCC初始浓度对镉的解吸影响。结果表明:WSCC对碳酸镉的增溶效果显著,当其质量浓度为2g/L时溶液中Cd2+可达到275mg/L;WSCC对镉解吸能力随着土壤中有机质含量的增加而降低,pH的升高、离子强度的增加和WSCC初始浓度的增加有利于镉的解吸;WSCC对镉污染土壤的解吸更符合准二级动力学方程,该静态解吸研究可以为镉污染土壤的修复提供基础信息及依据。

Study on desorption behavior of Cd2+ in soil with water-soluble carboxymethyl chitosans

Water-soluble chitosans(WSCC) with high water solubility and coordination ability for heavy metal was synthesized by the reaction of CTS with carboxymethyl.The performance of obtained WSCC for solubilization and desorption of cadmium in soil was studied,and the influence of pH,ionic strength,organic matter content and initial WSCC concentration on cadmium desorption was also investigated.The results showed that WSCC presented obvious solubilizing ability to cadmium carbonate,when the concentration of WSCC was 2 g/L,the concentration of Cd2+ in aqueous solution could reached to 275 mg/L.Higher organic matter content in soil resulted in lower desorption efficiency of WSCC for cadmium,and the desorption efficiency of cadmium increased with increasing pH,ionic strength and initial concentration of WSCC.The data of cadmium 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 cadmium contaminated soil.