2种吸附模型下非饱和土中污染物迁移规律分析

Analysis of Pollutants Migration in Unsaturated Soil Under Two Adsorption Models

在土壤污染物防控领域,涉及到污染物在土体中的迁移问题,基于土体中污染物质量守恒原理,建立等温线性平衡吸附和等温非线性平衡吸附2种模型下非饱和土中污染物迁移的数学模型,模型从液、固2相中污染物的质量守恒出发,描述非饱和土中污染物的迁移规律,通过Comsol Multiphysics软件对2种模型下污染物迁移输运规律进行了详细讨论.结果表明:在等温非线性平衡吸附模型下土体各点处污染物浓度大于等温线性平衡吸附模型结果,在分析污染物在吸附能力较强的粘性土中迁移或吸附性较强的金属离子在多孔介质中的迁移问题时,选择线性吸附模型更符合实际,否则会造成计算结果偏大.

In the field of soil contamination,it is concerned with the migration of pollutants in soil.Based on the mass conservation principle of contaminant in soil,a mathematical model of contaminant transport in unsaturated soils is established under the two models of linear and nonlinear isothermal equilibrium adsorptions to describe the law of pollutant migration in unsaturated soil accurately,based on the conservation of mass of pollutants in liquid and solid phases.And the law of pollutant migration under the two models is discussed in detail by using Comsol physics software.The results show that the pollutant concentration at each point of the soil mass is higher than that of the one-zone model under the nonlinear adsorption model,and the analysis results also show that when analyzing the migration of cohesive soil with stronger adsorption capacity or metal ions with stronger adsorption capacity in porous media,it is more practical to choose linear adsorption model,otherwise the calculation result will be too large.