有机质胶体对卡马西平在多孔介质中迁移影响模拟实验

发布时间：2019-05-27 06:09

【摘要】：有机质胶体与有机污染物的相互作用会影响污染物在多孔介质中迁移转化等环境行为.为研究有机质胶体对药物和个人护理品(PPCPs)在土壤环境中迁移的影响,本实验以卡马西平(CBZ)为目标污染物,用商用腐殖酸制备有机质胶体,分别选择石英砂、标准土和野外所取土样为研究介质,通过室内土柱模拟实验探究有机质胶体存在时污染物在多孔介质中的迁移行为.结果表明,描述一维溶质运移的两点化学非平衡模型能够较好模拟CBZ在各介质土中的运移过程,说明污染物运移过程中与介质间发生了化学非平衡吸附作用;石英砂柱中加入胶体后,对CBZ的吸附过程无明显影响,但在解吸时阻滞因子及滞留量变小,可见胶体与石英砂间作用微弱,解吸过程中胶体与污染物结合形成复合体后对污染物有增溶作用;胶体存在时,标准土和自然土对CBZ的吸附量和迁移阻滞强度均明显大于石英砂,其中有机质及黏土矿物的作用最为明显,有机质中的低能/高能吸附位点以及黏土矿物极性表面均能够固定污染物;由于有机质含量较高,自然土对CBZ在吸附-解吸过程中的阻滞截留强度大于标准土.针对本实验中CBZ的迁移情况,提出了疏水性有机污染物在含有机质胶体土壤中的迁移过程中各种作用的概念模型.
[Abstract]:The interaction between organic matter colloid and organic pollutants will affect the environmental behavior such as migration and transformation of pollutants in porous media. In order to study the effect of organic matter colloid on the migration of drug and personal nursing product (PPCPs) in soil environment, carbamazepine (CBZ) was used as the target pollutant to prepare organic matter colloid with commercial humic acid. Quartz sand was selected respectively. The standard soil and the soil samples taken in the field were used as the research medium. the migration behavior of pollutants in porous media in the presence of organic matter colloid was studied by indoor soil column simulation experiment. The results show that the two-point chemical non-equilibrium model describing one-dimensional solute transport can simulate the transport process of CBZ in each medium soil, which indicates that the chemical non-equilibrium adsorption occurs between the pollutant transport process and the medium. After adding colloid to quartz sand column, it had no obvious effect on the adsorption process of CBZ, but the blocking factor and retention decreased during desorption, which showed that the interaction between colloid and quartz sand was weak. In the process of desorption, colloid and pollutant combine to form complex, and it has solubilization effect on pollutants. In the presence of colloid, the adsorption capacity and migration blocking strength of CBZ in standard soil and natural soil are significantly higher than those in quartz sand, and the effect of organic matter and clay minerals is the most obvious. The low energy / high energy adsorption sites in organic matter and the polar surface of clay minerals can fix pollutants. Due to the high content of organic matter, the blocking and interception strength of CBZ in natural soil during adsorption and desorption was higher than that in standard soil. In view of the migration of CBZ in this experiment, the conceptual models of various roles of hydrophobic organic pollutants in soil containing organic colloids were proposed.
【作者单位】：中国地质大学(北京)水资源与环境学院水资源与环境工程北京市重点实验室;
【基金】：环境保护公益性行业科研专项(201309001-4) 中央高校基本科研业务费专项(35832015023)
【分类号】：X131

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