饱和非均质介质中PCE的运移分布与修复研究

Research of PCE migration and remediation of saturated heterogeneous media

重非水相液体(DNAPLs)泄漏进入土壤-地下水环境成为长期污染源,给人类健康及生态环境带来严重威胁。将四氯乙烯(PCE)作为特征污染物,通过二维砂箱实验探究饱和非均质介质中PCE的运移分布,及Tween 80溶液对PCE的去除效果。采用透射光法监测运移与修复过程,定量评估PCE的修复效率。结果表明,由于PCE无法克服毛细压力,在低渗透性介质上方聚积污染池;由于拉断效应,PCE在运移路径上以离散状形式存在。离散状PCE与Tween 80溶液的有效接触面积大,易被优先溶解去除,控制着修复效率。Tween 80溶液对离散状PCE修复效果显著,可作为有效的修复溶剂选用。

The dense non-aqueous phase liquids(DNAPLs)in subsurface act as long-term source zone,posing a serious threat to human health and the ecological environment.PCE was selected as a representative DNAPLs.The two-dimensional sandbox experiment was conducted to investigate the migration of PCE infiltration and source-zone flushing process.Light transmission method was used to monitor the migration and remove process of PCE within the sandbox,and evaluate the removal efficiency.Results showed that PCE accumulated on the low-permeability lenses,and laterally spread out since it did not build up enough pressure to overcome the entry pressure.PCE existed as discrete ganglia due to the snap-off effect on the migration pathway.PCE ganglia was preferentially solubilized by micelles due to a larger contact area with Tween 80 solution,and thus control the removal efficiency.Tween 80 solution can be selected as an effective solvent with significant removal efficiency.