特殊环境条件下复合重金属污染固化土中离子迁移特性分析

Analysis on the ion migration characteristics in solidified soil contaminated by complex heavy metals under special environmental conditions

运用有限元软件建立二维轴对称分析模型,研究了重金属离子(Cu^2+,Cd^2+)在土壤中的迁移扩散规律,对比了单一重金属离子(Cu^2+)和复合重金属(Cu-Cd)的迁移特性,分析了固化前后重金属的扩散规律,并考虑了温度和干湿作用的影响。结果表明:复合重金属在渗透过程中的迁移半径大于单一重金属离子的迁移半径;固化后的污染土对于重金属离子的扩散速率有着良好的控制作用,固化作用对单一重金属离子扩散的影响更为明显。环境温度对于重金属离子的扩散速率和范围呈现出正相关的影响;干湿循环作用下重金属离子的扩散范围明显增大。

A two-dimensional axisymmetric analysis model was established by using the finite element method.The migration and diffusion of heavy metal ions(Cu^2+,Cd^2+)in soil were studied.The migration characteristics of single heavy metal ions(Cu^2+)and composite heavy metals(Cu-Cd)were compared.The diffusion of heavy metals before and after solidification were analyzed,and the influences of temperature and dry-wet interaction were considered.The results show that the migration radius of composite heavy metals is larger than that of single heavy metal ions in the infiltration process.The solidified contaminated soil has a good control on the diffusion rate of heavy metal ions,and the effect of solidification on the diffusion of single heavy metal ions is more obvious.The environmental temperature has a positive correlation effect on the diffusion rate and range of heavy metal ions,and the diffusion range of heavy metal ions increases significantly under wet and dry cycles.