城市土壤吸附重金属动力学特征及其与土壤理化性质的关系

Adsorption Kinetic Characteristics of Heavy Metals in Urban Soils and the Relationship with the Physicochemical Properties of Soils

以长春市土壤为对象,既研究了长春市土壤理化性质特征,又采用间歇法研究了城市土壤吸附重金属Pb、Cd和Cu动力学特征及其两者之间的关系。结果表明:长春市土壤pH接近于中性或者偏碱性;土壤碳酸钙、有机质含量升高;土壤砂粒化;土壤CEC和Eh具有逐渐降低的趋势。土壤吸附重金属动力学过程包括快速阶段和慢速阶段,不同重金属在不同吸附阶段吸附速率明显不同。双常数速率方程和Elovich方程基本上可以描述土壤对Pb、Cd和Cu吸附的动力学过程。pH、碳酸钙和砂粒含量是影响Pb吸附速率的主要因子;碳酸钙含量是影响Cd吸附速率的主要因子。

The batch techniques were adopted to study the adsorption kinetics characteristics of Pb,Cd,Cu in soils from Changchun city, and the analytical methods of soil properties were adopted to study physicochemical properties of urban soils. Meanwhile multiple stepwise regression was used to define the chief factors influencing the adsorption kinetics characteristics of heavy metals in soils. The results showed that the pH of the soils in Changchun city approached to neuter or alkaline, and the amount of CaCO3 and organic matter in soils increased, but CEC, Eh and water content in soils tended to decrease gradually. According to the rate, the kinetic processes of heavy metals adsorbed by soils included fast phase and slow phase, and the adsorption rates of different heavy metals in different phases were diverse obviously. The kinetic processes of Pb,Cd,Cu adsorbed by soils could be described by the two constants equation and Elovich equation. The adsorption rate of Pb was mainly affected by pH,CaCO3 and the quantity of sand grain , and the adsorption rate of CA was mainly affected by the amount of CaCO3.