熱解吸對(duì)污染土壤中不同形態(tài)汞的去除作用

更新時(shí)間：2014-07-17 10:22 來源：環(huán)境工程學(xué)報(bào) 作者: 閱讀：2116

中文摘要:

選取貴州省萬(wàn)山礦區(qū)的汞污染土壤樣品進(jìn)行不同形態(tài)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(dòng)力學(xué)，以及溫度和時(shí)間對(duì)污染土壤中不同形態(tài)汞的去除作用。結(jié)果表明，熱解吸修復(fù)技術(shù)可有效去除土壤中的汞，土壤中∑Hg的熱解吸過程符合二級(jí)動(dòng)力學(xué)方程。固定熱解吸時(shí)間在10 min時(shí)，隨著熱解吸溫度的升高，土壤中水溶態(tài)汞、鹽酸溶態(tài)汞和堿溶態(tài)汞含量呈現(xiàn)先下降后上升再下降的趨勢(shì)，王水溶汞和鹽酸溶態(tài)汞始終呈現(xiàn)下降趨勢(shì)，說明不同形態(tài)的汞之間發(fā)生了轉(zhuǎn)化。熱解吸溫度為250℃時(shí)，隨著熱解吸時(shí)間的增加，環(huán)境風(fēng)險(xiǎn)大的水溶態(tài)汞、鹽酸溶態(tài)汞、堿溶態(tài)汞和硝酸溶態(tài)汞的去除率大幅增加，土壤的有機(jī)質(zhì)損失較少，說明在低溫下，延長(zhǎng)熱解吸時(shí)間，對(duì)生物毒性強(qiáng)的形態(tài)汞有良好的修復(fù)效果，且此溫度下處理后的土壤更容易恢復(fù)農(nóng)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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