土柱通风法去除表层土中氯化苦的模拟实验研究

Experimental Investigation and Numerical Modeling for Removal of Chloropicrin from Topsoil by Soil Vapor Extraction

土壤气相抽提 (SVE)技术广泛应用于不饱和土壤中挥发性有机污染物的去除。本实验采用土柱通风法模拟SVE ,对氯化苦在表层土中的迁移过程和去除效果进行了分析。当气体Darcy流速为 0 .0 1 3cm/s时 ,经过 2 .5天氯化苦在表层土中的含量由 2 0 0mg/kg降至一半 ,9天后氯化苦基本不残留。当气体Darcy流速提高到 0 .0 2 1cm/s时 ,氯化苦的挥发半残留时间降为 1天 ,共需 5天即可全部挥发。本文采用一维非平衡模型预测和评价挥发效果 ,模型模拟和实验结果吻合较好。

Soil vapor extraction (SVE) has been effectively used for the removal of volatile petrochemicals from unsaturated soil. Some of the commonly used soil fumigants also have high volatilization, which makes it possible to remove fumigants from topsoil by SVE. The removal of chloropicrin, a kind of commonly used volatile fumigant in China, was investigated in this paper. After 2.5 days' ventilation in the soil column, with a Darcy's velocity of 0.013cm/s, the chloropicrin content declines from 200?mg/kg to a half, and to zero after 9 days. While the velocity increases to 0.021?cm/s, the complete removal time shortens to 5 days. A non-equilibrium model was developed and described in this paper, which shows the consistency of the model and the experimental results.