a The Sericultural Research Institute of Hunan Province , Changsha , PR China.
Int J Phytoremediation. 2018 Mar 21;20(4):378-383. doi: 10.1080/15226514.2017.1393396.
In this study, the adsorption behavior of Cd ions by rhizosphere soil (RS) and non-rhizosphere soil (NS) originated from mulberry field was investigated. The Langmuir, Freundlich and the Dubinin-Radushkevich (D-R) equations were used to evaluate the type and efficiency of Cd adsorption. The RS was characterized by lower pH but the higher content of soil organic matter and cation exchange capacity (CEC) as compared to NS. Also, the maximum adsorption of Cd for RS (5.87 mg/g) was slightly bigger than that for NS (5.36 mg/g). In Freundlich isotherm, the K of the adsorption of Cd to surface of the RS components was higher than that of the NS, indicating stronger attraction between Cd and components of the RS. According to the D-R model, the adsorption of Cd by both soils was dominated by ion exchange phenomena. These results indicated that mulberry roots modified physical and chemical properties of the RS under field conditions, which also affected the Cd sorption efficiency by soil components during laboratory experiments. Current knowledge of the Cd sorption processes in the rhizosphere of mulberry may be important if these trees are planted for use in phytoremediation of Cd contaminated soils.
本研究考察了源于桑树种植地的根际土壤（RS）和非根际土壤（NS）对 Cd 离子的吸附行为。采用 Langmuir、Freundlich 和 Dubinin-Radushkevich（D-R）方程来评估 Cd 吸附的类型和效率。与 NS 相比，RS 的特点是 pH 值较低，但土壤有机质和阳离子交换容量（CEC）的含量较高。此外，RS 对 Cd 的最大吸附量（5.87 mg/g）略高于 NS（5.36 mg/g）。在 Freundlich 等温线中，Cd 对 RS 组分表面的吸附 K 值高于 NS，表明 Cd 与 RS 组分之间具有更强的吸引力。根据 D-R 模型，两种土壤对 Cd 的吸附均受离子交换现象的控制。这些结果表明，在田间条件下，桑树根系改变了 RS 的物理和化学性质，这也影响了实验室实验中土壤成分对 Cd 吸附效率。如果将这些树木种植在用于 Cd 污染土壤的植物修复中，那么了解桑树根际 Cd 吸附过程的知识可能很重要。
