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摘要
Batch sediment washing experiments were conducted to remove six metals (Cu, Zn, Ni, Cd, Cr, and Pb) from contaminated sediments. The effect of different operating parameters such as: type of washing solutions, reaction time, solution concentration, pH, and liquid/solid ratio were investigated. Besides, the kinetic of the extraction process was also studied. In the proposed work, cheating agent, i.e., di-sodium salt of ethylenediamine tetraacetate (Na(2)EDTA), was applied for extraction of heavy metals from contaminated sediment and showed significantly high efficiency compared with other agents. The extraction efficiency was 33%, 73%, 29%, 88%, 13%, and 83% for Cu, Zn, Ni, Cd, Cr, and Pb, respectively, at a 0.1 M Na(2)EDTA washing solution, liquid/solid ratio of 10, pH 4.0, and 2 h washing time. The chelant extraction process was a first-order reaction. The k(1) (apparent rate constant for metal desorption) values were 0.0822-0.5598 h(-1), and the order was Pb > Zn > Cd > Ni > Cu > Cr. Moreover, the results indicated that the extraction efficiency of metals is directly proportional to the liquid/solid ratio and concentration of washing solution while inversely proportional to the pH in the range of 3-10. The results will be useful as preliminary evaluation of the removal of heavy metals from the contaminated sediments using chelating agents in washing operation.
- 出版日期2017-4
- 单位中山大学
