不同路域植被类型土壤对Cu^(2+)和Pb^(2+)吸附特性的比较

A Comparative Study of the Adsorption Characteristics of the Cu^(2+) and Pb^(2+) into Soils with Different Vegetation along the Road Area

采用振荡平衡法研究Cu2+和Pb2+两种重金属在长春地区一些典型路域植被土壤中的热力学和动力学吸附特性.结果表明:这两种重金属在不同土壤中的吸附等温线均符合Langmuir方程和Freundlich方程,但Langmuir方程的拟合效果更好,即两种重金属在不同土壤中的吸附过程更接近单分子层吸附模型;灌木丛植被类型的土壤对Cu2+和Pb2+的饱和吸附量最大,分别为3 429,5 311mg/kg;灌木丛植被类型的土壤对重金属的吸附速率最大,由Elovich方程可知,这与该土壤的pH值、阳离子交换量(CEC)、有机质含量和黏粒含量较高等理化性质有关,且Pb2+比Cu2+更易被土壤吸附.

In order to understand the migration and trans[ormation of heavy metal pollutants in the soil covered by different road area vegetation in the Changchun area, the thermodynamics and kinetics of the adsorption of Cu2＋ and Pb2＋ in these soils were studied with the batch equilibration method. The results show that the adsorption isotherms of the two heavy metals in different soil both [it the Langmuir equation and Freundlich equation, but both better fit the Langmuir equation, which shows that the adsorption process was closer to the monolayer adsorption model. For the soil covered with the bush vegetation, the saturation adsorption capacities o{ the Cu2＋ and Pb2＋ were the largest, respectively reached 3 429, 5 311 mg/kg. Elovich equation can describe the adsorption kinetics processes of the Cu2＋ and Pb2＋ in these different soil better, the adsorption rate of the heavy metals into the soil covered with bush vegetation was the largest. The adsorption of these metals into the different soil was related to high pH value, CEC, organic matter content, clay content and other physical and chemical properties. The results show that Pb2＋ was easier to be absorbed by the soil than Cu2＋ , which was related to the physical and chemical properties of the heavy metals.