中文摘要：

采用1次平衡法对Cd^2＋、Pb^2＋在小麦根际和非根际土壤中的吸附。解吸行为进行比较研究．结果表明，根际土对Cd^2＋和Pb^2＋的吸附能力高于非根际土，2类土壤对Cd^2＋的吸附等温线与Freundlich方程有较好的拟合性，Pb^2＋的等温吸附过程可由Langmuir方程与Freundlich方程来描述．双常数方程是描述根际、非根际土Cd^2＋和Pb^2＋吸附动力学行为的最优模型，其次为Elovich方程，最差模型是一级动力学方程．Cd^2＋、Pb^2＋的解吸存在滞后现象，相比于非根际土，根际土吸附态Cd^2＋、Pb^2＋的解吸率更低，Cd^2＋、Pb^2＋的解吸量与其初始吸附量之间的关系符合2次幂方程．2类土壤Cd^2＋、Pb^2＋的解吸速率随重金属初始浓度的增加而增加，随解吸时间的延长而不断降低．描述根际和非根际土Cd^2＋、Pb^2＋的解吸动力学过程的最优模型均为双常数方程，其次为Elovich方程，一级动力学方程拟合效果不佳．

英文摘要：

Sorption-desorption behavior of Cd^2＋ and Pb^2＋ in the rhizosphere and bulk soil of wheat was studied by the batch method. The results indicated that the sorption capacity of rhizosphere soil to Cd^2＋ and Pb^2＋ was higher than that of bulk soil. Isothermal curves of Cd^2＋ sorption by rhizosphere and bulk soil fitted Freundlich equation well. Isothermal sorption process of Pb^2＋ could be well described by Langmuir equation and Freundlich equation. Two - constant equation was the best model to describe the sorption kinetics of Cd^2＋ and Pb^2＋ , followed by Elovich equation, and the worst model was first-order dynamics equation. There was sorption-desorption hysteresis of Cd^2＋ and Pb^2＋ . The desorptive rates of Cd^2＋ and Pb^2＋ in rhizosphere soil was lower than that of bulk soil. The relationship between desorptive quantity of Cd^2＋ and Pb^2＋ in two soils and the initial sorptive quantity coincided with quadratic equation. The desorptive rates of Cd^2＋ and Pb^2＋ in two soils increased with the higher initial concentrations of Cd^2＋ and Pb^2＋ in the treatments, and decreased with the increasing desorptive time. Two- constant equation was the optimal model to describe the desorptive kinetics of Cd^2＋ and Pb^2＋ in the two soils, and followed by Elovich equation, while the first-order dynamics equation fitted not well.