土壤电动修复中菲迁移的数值模拟

Simulation on phenanthrene migration in electrokinetic remediation of soil

针对菲污染土壤修复建模的问题,通过对电动力学作用下菲污染土壤的迁移现象的室内模拟实验,确定了影响菲迁移的电渗流、电迁移、对流和弥散4个主要过程,建立了电动力学作用下菲在污染土壤中的迁移模型;运用COMSOL Multiphysics 5.3软件结合迁移模型的各项方程和选取的参数对菲的迁移过程进行了模拟计算。结果表明:当孔隙率分别为0.33、0.38、0.43和0.48时,菲的最大迁移率分别为31.89%、34.78%、37.97%和41.74%;当电压从0.5 V·cm^-1增加至2 V·cm^-1的过程中,电渗流通量增大,最大迁移率可达到44.35%;修复区域的浓度均呈"碗状"分布,模拟计算得到在中间靠近阳极区域的菲的浓度达到最小值2.14 mol·m^-3,迁移率最大为38%。模拟计算的菲迁移分布结果与实验所得结果相吻合,证明该模型用于电动修复多环芳烃污染土壤的适用性。

In order to address the problem of repairing phenanthrene-contaminated soil,both laboratory simulation and experiments were conducted to study the phenanthrene migration in soil under electrodynamics.Electroosmotic flow,electromigration,convection,and dispersion were determined to be the four main processes to affect phenanthrene migration.A phenanthrene migration model in contaminated soil under electrodynamics was established.The phenanthrene migration process was simulated using COMSOL Multiphysics 5.3 software,the migration equations and the selected parameters.Results showed that at the porosities of 0.330,0.380,0.430,and 0.480,the maximum mobility of phenanthrene were 31.9%,34.8%,38.0% and 41.7%,respectively.As the voltage increased from 0.500 V·cm^-1 to 2.00 V·cm^-1,the electroosmotic flux increased accordingly,resulting in a maximum mobility of 44.4%.In the remediation area,a bowl-shaped distribution occurred for the phenanthrene concentration.The simulation calculation determined that phenanthrene concentration reached a minimum value of 2.14 mol·m^-3 in the middle region close to the anode,and the maximum mobility was 38.0% accordingly.The simulated results for phenanthrene migration and distribution were in a good agreement with the experimental results,which verified that the applicability of the developed model in the electrokinetic remediation of soil contaminated by polycyclic aromatic hydrocarbon.