| Cd2+、Pb2+在根际和非根际土壤中的吸附-解吸行为 |
| 摘要点击 3923 全文点击 1589 投稿时间：2006-05-07 修订日期：2006-07-03 |
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| 中文关键词 Cd2+ Pb2+ 根际土 非根际土 吸附-解吸 |
| 英文关键词 Cd2+ Pb2+ rhizosphere soil bulk soil sorption-desorption |
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| 中文摘要 |
| 采用1次平衡法对Cd2+、Pb2+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Cd2+和Pb2+的吸附能力高于非根际土，2类土壤对Cd2+的吸附等温线与Freundlich方程有较好的拟合性，Pb2+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Cd2+和Pb2+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.Cd2+、Pb2+ 的解吸存在滞后现象，相比于非根际土，根际土吸附态Cd2+、Pb2+ 的解吸率更低，Cd2+、Pb2+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Cd2+、Pb2+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Cd2+、Pb2+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 Cd2+ and Pb2+ 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 Cd2+ and Pb2+ was higher than that of bulk soil. Isothermal curves of Cd2+ sorption by rhizosphere and bulk soil fitted Freundlich equation well. Isothermal sorption process of Pb2+ could be well described by Langmuir equation and Freundlich equation. Two - constant equation was the best model to describe the sorption kinetics of Cd2+ and Pb2+, followed by Elovich equation, and the worst model was first-order dynamics equation. There was sorption-desorption hysteresis of Cd2+ and Pb2+. The desorptive rates of Cd2+and Pb2+ in rhizosphere soil was lower than that of bulk soil. The relationship between desorptive quantity of Cd2+ and Pb2+ in two soils and the initial sorptive quantity coincided with quadratic equation. The desorptive rates of Cd2+ and Pb2+ in two soils increased with the higher initial concentrations of Cd2+ and Pb2+ in the treatments, and decreased with the increasing desorptive time. Two-constant equation was the optimal model to describe the desorptive kinetics of Cd2+ and Pb2+ in the two soils, and followed by Elovich equation, while the first-order dynamics equation fitted not well. |
