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中国农学通报

中国农学通报 ›› 2009, Vol. 25 ›› Issue (3): 255-259.

• 资源 环境 生态 土壤 气象 • 上一篇    下一篇

镉在针铁矿和腐殖酸及其复合胶体中的吸附解吸行为比较研究

罗文倩,魏世强   

  • 收稿日期:2008-11-16 修回日期:2008-12-02 出版日期:2009-02-05 发布日期:2009-02-05

Adsorption and Desorption Behaviors of Cadmium on/from Goethite ，Humic Acid and Its Compound Colloid with Humic Acids

  • Received:2008-11-16 Revised:2008-12-02 Online:2009-02-05 Published:2009-02-05

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摘要： 采用批平衡实验法，比较研究了重金属镉在针铁矿、腐殖酸及针铁矿—腐殖酸复合胶体中的吸附热力学和动力学特征。结果表明，在试验浓度范围内，三种吸附剂对Cd2+的等温吸附特征均可用Langmuir、Freundlich和Linear方程加以描述。其中以Langmuir方程的拟合效果最佳，线性相关系数为：0.991、0.996、0.999，由此得出的最大吸附量分别为41.67、38.46、45.46 mg/g，表明腐殖酸与针铁矿复合胶体较两者单一体系的吸附力有所提高，且所吸附的镉均难以解吸，平均解吸率分别为5.871% 、5.918%、1.068%。三种吸附剂对Cd2+的吸附可分为两个阶段，即吸附开始4h内的快速反应阶段和此后的慢速反应阶段，在前4h的快速吸附阶段，吸附量可达到平衡吸附量的90%-95%

关键词: 玉米, 玉米, 抗除草剂基因, 苏云金杆菌毒蛋白基因, 半夏凝集素基因, 转基因

Abstract: The thermodynamics and kinetics of Cd2+ adsorption and desorption on/from goethite， humic acid and its compound colloid with humic acids were studied by batch experiments. The results showed that within the range of cadmium concentration tested， Cd2+ adsorption was increased with the increase of its initial concentration， and the compound colloid had a higher Cd2+ adsorption capacity than goethite and humic acid. The adsorption isotherms of Cd2+ by the three samples could significantly confirm to Langmuir，Freundlich and Linear equation， while Langmuir was the best one. The maximum adsorption of Cd2+ by the three tested samples was 41.667，38.461，45.455 mg/g，respectively，according to Langmuir equation. The compound colloid had a lower Cd2+ desorption rates than goethite and humic acid， which was only 1.068% as compared to 5.871% from goethite and 5.918% from humic acid， indicating that compound colloid had a higher adsorption strength for cadmium. The kinetics of Cd2+ adsorption reactions by the three tested samples could be divided into two stages, namely the fast adsorption process with 4 hours, which could reach 90%~95% of the equilibrium, and a slow adsorption process afterwards.