线性等温吸附条件下有机污染物在地下饱水带中迁移的数学模型及参数分析

Mathematical model for the migration of organic pollutant in saturated water zone under the linear isothermal equilibrium adsorption condition and analysis of its parameters

为研究在固-液界面的吸附降解等行为对饱水带中的有机污染物的迁移转化过程的影响,综合考虑有机污染物在饱水带中的扩散、吸附解吸、分配以及微生物降解作用,根据线性等温平衡吸附理论,建立了地下水流动方程与有机污染物在饱水带中迁移方程耦合的数学模型,探讨了模型中的分配系数及溶解项、吸附项的一阶反应速率等参数的改变对有机污染物运移规律的影响.结果表明,随着分配系数的增大,有机污染物因固相介质的吸附和截留而被限制其随地下水迁移;微生物降解作用对有机污染物的浓度有重要影响,随着反应速率的改变,污染物在固相和水相中的浓度迅速改变.本文的研究结果为定量描述溶质迁移过程提供理论依据,同时也为实验室中模型参数的测定提供可靠的依据.

This paper aims at studying the effects of the some behaviors on the solid—fluid interface such as adsorption,desorption,degradation etc.on the migration of organic pollutant in saturated water zone.Based on the linear isothermal equilibrium adsorption theory,the coupling model of underground water flow equation and the organic pollutant migration equation in saturated water zone is established under considering the diffusion,adsorption and desorption,distribution and biodegradation of organic pollutant in saturated water zone.The effects of the parameters in the model——distribution coefficient,one-order reaction rate of dissolved phase and one-order reaction rate of adsorption phase——on the migration law of the organic pollution in saturated water zone are discussed.It is shown that,with the increase of the distribution coefficient,the adsorption of solid media controls the migration of the organic pollution;the biodegradation has great effect on the concentration of the organic pollution in underground water,the concentration rapidly changes with the variation of reaction rate.The study result in this paper can provide theoretical basis for quantitatively describing the migration process of solvent and provide reliable basis for measuring the model parameters in laboratory.