垃圾防渗粘性土对多环芳烃菲(PHEs)的吸附作用研究

研究了持久性有机污染物多环芳烃菲(PHEs)在垃圾防渗粘性土中的吸附机理规律及其吸附模型,探讨了pH值及土样颗粒等影响因素对吸附效果的作用机制,提出了垃圾填埋场防渗粘性土的优化设计。结果表明:菲在粘性土中的吸附过程包括4个阶段,达到吸附平衡的时间为9h;吸附等温线符合Freundlich模型,相关系数为0.98,属于非线性等温吸附;菲的水-土分配系数Kd为0.01,有机碳和水之间的分配系数为14.29;当pH值7.42时,土样对菲的吸附量随pH值的增大而迅速增大;pH值7.42的酸性环境中,对菲的吸附量也变大,但是随着酸性的加强,当pH值6.74之后,吸附能力不再有明显变化;菲的最大吸附量与土体的粘粒含量、比表面积呈正比,由大到小顺序为粘性土粉质粘土细砂。

Adsorption Behavior of Polycyclic Aromatic Hydrocarbon Phenanthrene on Anti-permeation Clayey Soil in Landfill

The clay adsorption rule and adsorption models of polycyclic aromatic hydrocarbons (PHE)that is belonged to persistent organic pollutants,which were studied through the experiments of adsorption kinetics.Influences of pH and particle size on adsorption isotherm were studied.According to the experimental results,the adsorption mechanism and the influencing factors were discussed.It was found that the entire adsorption process has undergone four stages,and the adsorption equilibrium time was nine hours.The adsorption isotherm fit better with Freundlich model with a correlation coefficient of 0.98,which belonged to non-linear isothermal adsorption.The soil-water partition coefficient of Philippine(Kd)was 0.01,and the organic carbon and water partition coefficient was 14.29.When pH>7.42,the adsorption capacity of soil samples increased rapidly with the pH value became larger.When pH<7.42,it would increased with pH value became smaller at the same time,but when pH<6.74,the adsorption capacity was no longer changed significantly.The max adsorption capacity of Phe was proportional to the content of the soil clay and specific surface area.Descending order of the adsorption capacity was clay>silty clay>fine sand.