DTPA浸提条件下土壤性质对镉浸提效果的影响

Influence of Soil Properties on Cadmium Leaching Efficiency under DTPA Leaching Condition

为研究土壤理化性质对二乙基三胺五乙酸(DTPA)浸提条件下镉浸出效果的影响,对27个镉污染土样进行连续15 d浸提批实验,计算15 d时镉浸提率与土壤/溶液镉分配系数Kd,探究这两个指标随土壤性质的变化。结果显示,浸提发生10 min时有0.24±0.11比例的镉被浸提,最终浸提率为0.59±0.20,Kd值为22.13±17.71 L·kg-1。镉浸提率与初始镉浓度、有机质含量(OM)、粘粒含量呈正相关;与阳离子交换量(CEC)、粉粒含量呈负相关。Kd值与初始镉浓度、OM、粘粒含量显示出显著对数线性负相关,随CEC、粉粒含量呈对数线性增加。本研究对土壤重金属修复有参考意义。

Experiments are carried out to investigate the influence of soil properties on soil cadmium(Cd)leaching efficiency assisted by diethylenetriamine pentaacetatic acid(DTPA).A batch of leaching experiments on 27 Cd-polluted soils is performed for 15 days in the laboratory.The extraction proportion and soil/solution distribution coefficient(K d)are calculated.The results show that 0.24±0.11(mean value±standard deviation)Cd is leached at 10 min,while the final DTPA-assisted leaching proportion are 0.59±0.20 and the K d is 22.13±17.71L·kg^-1.The leaching proportion of Cd is positively correlated with the initial cadmium concentration and the organic matter(OM)and clay contents,and negatively correlated with the cation exchange capacity(CEC)and the silt content.A significant negative logarithmic linear correlation is shown between the K d value and the initial cadmium concentration and the OM and clay contents,while a positive logarithmic linear correlation is observed between the K d value and the CEC and silt content.The present study could be useful reference to the remediation of heavy metal pollution in soils.