熱解吸對污染土壤中不同形態汞的去除作用

更新時間：2014-07-17 10:22 來源：環境工程學報作者: 閱讀：2010

中文摘要:

選取貴州省萬山礦區的汞污染土壤樣品進行不同形態汞的熱解吸去除行為研究。研究了熱解吸過程中∑Hg的去除效果及動力學，以及溫度和時間對污染土壤中不同形態汞的去除作用。結果表明，熱解吸修復技術可有效去除土壤中的汞，土壤中∑Hg的熱解吸過程符合二級動力學方程。固定熱解吸時間在10 min時，隨著熱解吸溫度的升高，土壤中水溶態汞、鹽酸溶態汞和堿溶態汞含量呈現先下降后上升再下降的趨勢，王水溶汞和鹽酸溶態汞始終呈現下降趨勢，說明不同形態的汞之間發生了轉化。熱解吸溫度為250℃時，隨著熱解吸時間的增加，環境風險大的水溶態汞、鹽酸溶態汞、堿溶態汞和硝酸溶態汞的去除率大幅增加，土壤的有機質損失較少，說明在低溫下，延長熱解吸時間，對生物毒性強的形態汞有良好的修復效果，且此溫度下處理后的土壤更容易恢復農田耕作。

英文摘要:

Mercury-contaminated soil samples from Wanshan mining area in Guizhou Province were treated with thermal desorption process to investigate the removal of mercury speciations.Removal of ∑Hg and its kinetics were discussed,and the removal efficiencies of different mercury speciations were investigated at different temperatures and times as well.The experimental results indicated that thermal desorption could effectively remove mercury from the soil.Kinetics of thermal desorption process of ∑Hg from soil can be well interpreted by the second rate equation.When treated for 10 min,with the rise of temperature,the concentration of water-soluble mercury,acid soluble-mercury and alkaline solublility mercury in soil were found to decrease at low temperature,then increase afterwards and decrease at last,but the concentrations of the other two mercury speciations decreased all the time,which indicates that transformation may happen between different mercury speciations.At 250℃,with the increase of treated time,the concentration of water-soluble mercury,acid soluble mercury,alkaline solublility mercury and nitric acid soluble mercury were reduced greatly,and the loss of organic matter in soil was less,suggesting that low temperature with long-time treatment can reduce the risk of Hg in soil,and help soil to restore farmland tillage.

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