六价铬在具有渗透性反应墙的渗流槽中迁移实验研究

地下水中六价铬的污染修复是目前地下水污染修复研究的热点课题之一。以室内模拟为基础,进行了六价铬[Cr（Ⅵ）]随水流迁移的渗流槽实验,以及利用课题组研发的新型壳聚糖材料填充渗透性反应墙（PRB）,进行六价铬吸附试验研究。结果表明：在重金属迁移实验中,地下水的流速是影响Cr（Ⅵ）在含水层中迁移的主要因素,含水层介质的变化都会对Cr（Ⅵ）的迁移发生重要的影响。实验过程中,从进水口到出水口各个取样点依次出现Cr（Ⅵ）的质量浓度峰值,并且随着时间的延长,质量浓度峰值没有减少的趋势,证明了Cr（Ⅵ）在含水介质中基本上没有吸附。Cr（Ⅵ）的质量浓度峰值在含水介质中的持续时间不长,由于弥散作用造成了在相当长的时间内的较明显的拖尾现象。模拟渗透性反应墙的实验中,在同样的流速条件下,Cr（Ⅵ）的质量浓度峰值的出现时间相对先前的实验有明显滞后,并且质量浓度也有明显的减少,说明新型壳聚糖材料对Cr（Ⅵ）有较高的吸附作用,再达到质量浓度的峰值后,墙体后面的采样口中Cr（Ⅵ）的质量浓度减少的更为平缓,说明随着水流的流动,吸附在壳聚糖材料上的Cr（Ⅵ）有缓慢的析出。

Experiment on sexavalent chromium transport in seepage sand box with permeable reactive barrier

Remediation of groundwater contaminated by sexavalent chromium is a hot research on groundwater contaminant remediation.Based on seepage sand box experiments,in this paper authors have carried on experiment on Cr（Ⅵ） transport and adsorption in seepage sand box with permeable reactive barrier（PRB）.The results indicate that（1） the impact of groundwater flow（advection） is the main factor of Cr（Ⅵ） transport.Changes in permeability of aquifer will have a large impact on the Cr（Ⅵ） transport.In addition,the peak concentration of Cr（Ⅵ） has appeared in turn and it don＇t decline with time.The duration of peak concentration is not too long,but smearing phenomenon has occurred obviously in a quite long time.This phenomenon is due to diffusion.In this experiments,when the water went through the permeable reactive barrier（PRB） at the same flow rate,the time when the peak of the Cr（Ⅵ） occurred lagged behind than previous experiments and there was a mark decrease in concentration,it shows that the adsorption material has a higher adsorption capacity of Cr（Ⅵ）,the peak concentration reached after the wall decreased more slowly,indicating the Cr（Ⅵ） precipitated slowly with the water flow.