通过吸附实验及释放实验,研究了包头市南海湖表层沉积物对Cd^2+的吸附、释放作用。结果表明,Cd^2+在南海湖沉积物上的吸附既符合Langmuir型又符合Freundlich型,且以Langmuir型为最佳;Cd^2+的吸附对pH值依赖程度较高,随pH值的增高而增强;温度的降低,离子强度和泥沙浓度的增加,均不利于南海湖沉积物对Cd^2+的吸附。在6 h以内,Cd^2+的释放百分率随时间的增加而增大,并于6 h达到极值,6 h后急剧下降,并在10 h后趋于平稳;Cd^2+的释放百分率随pH值的升高而降低。弱酸至碱性环境有利于Cd^2+的吸附,酸性环境有利于Cd^2+的释放。
The Nanhai Lake (E 109°59′2″-110°2′26″, N 40°30′08″-40°33′32″) located in Nanhai wetland nature reserve in Baotou City of north China. This research mainly focuses on the adsorption and release of Cd^2+ on the surface sediments of the Nanhai Lake. The results were described as follows:The Freundlich isotherm type model and Langmuir isotherm type model were used in this study, which were all fit the experimental equilibrium of Cd^2+, and the Langmuir isotherm type model was better. In adsorption experiments, the adsorptive capacities of Cd^2+ increased with pH and temperature, decreased with ionic strength and sediment concentration. While in release experiments, the release percentage of Cd^2+ changes fluctuated during beginning 10 h, reached the maximum (9%) at 6 h, and smooth out after 10 h. Lower pH and acid condition were propitious to Cd^2+ release.