气相抽提去除红壤中挥发性有机污染物的去污机理探讨

DECONTAMINATION MECHANISM OF THE VOLATILE ORGANIC COMPOUND REMOVAL FROM RED EARTH BY SOIL VAPOR EXTRACTION

通过探讨土壤气相抽提去除红壤中挥发性有机污染物的去污机理,建立了一维稳态条件下污染物在土壤多孔介质中传质的总微分方程,分别求出了平衡模型和动力学模型的解析解和数值解,并用实验结果对平衡模型和动力学模型进行了模拟和验证.实验结果和模型模拟结果表明理论模型与实验结果吻合良好,平衡模型和动力学模型在描述污染物在土柱通风过程中的传质时,分别适用于不同的阶段.在通风初期平衡模型能够很好地描述实验结果,而随着时间的推移,平衡模型的预测曲线逐渐偏离数据点,到了通风中后期,只有动力学模型才能够较好地描述和预测实验结果.

Soil Vapor Extraction（SVE）has been widely used to remove volatile organic compounds （VOCs） from unsaturated soil.It is safe,economical,and highly efficient.In this paper,a total differential equation of the mass transfer in soil porous media under one-dimensional steady-state has been established,followed by the decontamination mechanism study of VOCs removal from red earth through SVE.Then analytic and numerical solutions were acquired for balanced and kinetic models,respectively.Results of the experiments and model simulations showed that the two in good agreement.For mass transfer of contaminant,the balanced and kinetic model were applied to different stages of soil column ventilation process.At the beginning of ventilation,a balanced model matched the experimental results well.However,as time went by,the balanced model prediction curve gradually deviated from data points.By the end of ventilation,only the kinetic model could describe and predict experimental results.