污染质在多孔粘土屏障内扩散的实验研究

Experimental study on diffusion of contaminant in porous soil barrier

污染质的运移主要由三种方式组成弥散、吸咐和衰减转化。弥散主要包括分子扩散和渗透分散。当研究没有渗流或低水流的垃圾场内污染质穿透屏障墙的行为时,可以不考虑分子渗透分散,但必须考虑分子扩散作用。设计了一个有浓度差、无水头差的实验装置,并用量纲分析方法建立了相应的力学数学模型,来分析屏障墙对污染质离子的控制作用,测定了多种离子在粘土介质中运移的扩散系数,验证了Fick第二定律的基本假定,同时还发现了阴离子在土壤中扩散速度普遍比阳离子大的现象,并对此进行了解释,讨论了温度、流程、屏障材料的性质对离子扩散系数的影响。

Contaminant migration is mainly composed of three aspects, that is, dispersion, absorption and decaying transform. Dispersion also includes molecule diffusion and saturated disperse. The experiment has been designed as a kind of model with three rooms. The concentration grad is the only potency to drive the contamination to environmental medium without water head difference between the two filled liquid rooms. By dimension analysis, a mechanical and math model has been established for investigating the law of some ion contaminants changes when they dispersed. The diffusion coefficients of many ions have been determined in the experiment which also proved the basic assumption of Fick's second law. The experiment results also show that the anion disperses more quickly than ion.