Seo Dong Cheol, Yu Kewei, DeLaune Ronald D
Department of Oceanography and Coastal Sciences, School of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803, USA.
Chemosphere. 2008 Dec;73(11):1757-64. doi: 10.1016/j.chemosphere.2008.09.003. Epub 2008 Oct 16.
Monometal and multimetal adsorption of selected heavy metals in a sediment from a coastal Louisiana forested swamp used for wastewater treatment was studied. Results from the batch experiments show that the maximum adsorption capacities of the metals by the sediment were in the order of Pb>>Hg>Cr>CdCuZn>>As based on monometal adsorption isotherm, and Hg>Cr>CuCd approximately Pb>>As approximately Zn based on multimetal adsorption isotherm, respectively. Batch experimental data best fit the Langmuir model rather than the Freundlich isotherms. In the column experiments, the maximum adsorption capacities of the metals were in the order of Pb>>Hg>Cr>Cd>Cu>Zn>>As in monometal conditions, and Hg>>Cr>>Pb>CuZn approximately Cd>As in multimetal conditions. The metals became more mobile in multimetal than in monometal conditions. Results from both the batch and column experiments show that competitive adsorption among metals increases the mobility of these metals. Particularly, in this study, Pb in multimetal conditions lost it adsorption capacity most significantly. In both monometal and multimetal conditions, the maximum adsorption capacity of the metals in the column experiments was higher than that in the batch experiment indicating other metal retention mechanisms rather than adsorption may be involved. Therefore, both column and batch experiments are needed for estimating retention capacities and removal efficiencies of metals in sediments.
对路易斯安那州沿海一片用于废水处理的森林沼泽沉积物中选定重金属的单金属和多金属吸附进行了研究。批量实验结果表明，基于单金属吸附等温线，沉积物对金属的最大吸附容量顺序为Pb>>Hg>Cr>Cd>Cu>Zn>>As；基于多金属吸附等温线，顺序分别为Hg>Cr>Cu>Cd≈Pb>>As≈Zn。批量实验数据最符合朗缪尔模型，而非弗罗因德利希等温线。在柱实验中，单金属条件下金属的最大吸附容量顺序为Pb>>Hg>Cr>Cd>Cu>Zn>>As，多金属条件下为Hg>>Cr>>Pb>Cu>Zn≈Cd>As。多金属条件下金属的迁移性比单金属条件下更强。批量实验和柱实验结果均表明，金属间的竞争吸附增加了这些金属的迁移性。特别是在本研究中，多金属条件下的Pb吸附容量损失最为显著。在单金属和多金属条件下，柱实验中金属的最大吸附容量均高于批量实验，这表明可能涉及除吸附之外的其他金属保留机制。因此，需要同时进行柱实验和批量实验来评估沉积物中金属的保留容量和去除效率。
