热解吸对污染土壤中不同形态汞的去除作用

摘要: 选取贵州省万山矿区的汞污染土壤样品进行不同形态汞的热解吸去除行为研究。研究了热解吸过程中∑Hg的去除效果及动力学，以及温度和时间对污染土壤中不同形态汞的去除作用。结果表明，热解吸修复技术可有效去除土壤中的汞，土壤中∑Hg的热解吸过程符合二级动力学方程。固定热解吸时间在10 min时，随着热解吸温度的升高，土壤中水溶态汞、盐酸溶态汞和碱溶态汞含量呈现先下降后上升再下降的趋势，王水溶汞和盐酸溶态汞始终呈现下降趋势，说明不同形态的汞之间发生了转化。热解吸温度为250℃时，随着热解吸时间的增加，环境风险大的水溶态汞、盐酸溶态汞、碱溶态汞和硝酸溶态汞的去除率大幅增加，土壤的有机质损失较少，说明在低温下，延长热解吸时间，对生物毒性强的形态汞有良好的修复效果，且此温度下处理后的土壤更容易恢复农田耕作。

中文摘要:

选取贵州省万山矿区的汞污染土壤样品进行不同形态汞的热解吸去除行为研究。研究了热解吸过程中∑Hg的去除效果及动力学，以及温度和时间对污染土壤中不同形态汞的去除作用。结果表明，热解吸修复技术可有效去除土壤中的汞，土壤中∑Hg的热解吸过程符合二级动力学方程。固定热解吸时间在10 min时，随着热解吸温度的升高，土壤中水溶态汞、盐酸溶态汞和碱溶态汞含量呈现先下降后上升再下降的趋势，王水溶汞和盐酸溶态汞始终呈现下降趋势，说明不同形态的汞之间发生了转化。热解吸温度为250℃时，随着热解吸时间的增加，环境风险大的水溶态汞、盐酸溶态汞、碱溶态汞和硝酸溶态汞的去除率大幅增加，土壤的有机质损失较少，说明在低温下，延长热解吸时间，对生物毒性强的形态汞有良好的修复效果，且此温度下处理后的土壤更容易恢复农田耕作。

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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