摘要
介绍了利用一种自制的特殊装置,测定污染物离子在掺入粉煤灰的饱和粘土介质中迁移的扩散系数D和分配系数Kd的方法.通过一系列污染物在粉煤灰-粘土介质中的纯扩散迁移试验,运用一个简单的理论模型,通过拉普拉斯(Laplace)变换方法,对一个单独的试验,可同时推断出扩散系数和分配系数.镍和锌的扩散试验结果表明:粉煤灰对金属离子的阻滞作用是明显的,使离子的扩散系数大大降低,锌离子在掺入10%~20%粉煤灰的粘土介质中的有效扩散系数降幅达20~40倍;但粉煤灰的掺入量不一定越大越好,对镍和锌离子的扩散而言,粉煤灰的掺入量为10%~15%即可.并且,从源浓度求得的扩散系数D和有效扩散系数D*值比从土屏障中浓度剖面得出的要大.
This paper introduces a technique for determining the diffusion coefficients and distribution coefficients of contaminants passing through saturated fly ash-clay samples. The technique is illustrated on the basis of a number of laboratory tests involving pure diffusion migration of contaminants through fly ash-clay media from Shanghai, China. A simple theoretical model is used to analyze the test and result shows that the diffusion coefficient and distribution coefficient from a single test can be deduced by Laplace transform method. The diffusion experiments results of Zn^2 ＋ , Ni^2 ＋ show that the hindrances effect of fly ash on diffusion of Zn^2 ＋ , Ni^2 ＋ in fly ash-clay media is apparent. The diffusion coefficients in clay added with fly ash decrease dramatically. In this experiment, the effective diffusion coefficients of Zn^2＋ in clay decrease by 20-40 times after 10-20 percent fly ash is added into clay. The results also indicate that the diffusion coefficients of Zn^2 ＋ , Ni^2 ＋ in saturated fly ash-clay media do not neces- sarily decrease as the amount of fly ash added into clay increases. The appropriated amount of fly ash added into clay is 10-15 percent based on the result of diffusion experiments of Zn^2＋ , Ni^2＋ in different fly ash-clay mixtures in this study. Also, D and D^＊ values derived from reservoir concentration are higher than D and D^＊ values derived from soil concentration profiles.
出处
《同济大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2007年第11期1520-1524,共5页
Journal of Tongji University:Natural Science
基金
上海市科技发展基金项目(022312202)
同济大学文远基金
关键词
污染物
粉煤灰
扩散系数
分配系数
粘土
contaminant
fly ash
diffusion coefficient
distribution coefficient
clay
