氯苯污染土壤低温原位热脱附修复

In-situ low temperature thermal desorption for remediation of the chlorobenzene contaminated soil

为了考察低温原位热脱附技术对土壤中氯苯的修复效果,以土壤中氯苯为目标污染物,控制热脱附设备设定温度、土壤粒径、土壤含水率,对不同条件下土壤中的氯苯进行测定分析,研究其对热脱附效果的影响。结果表明:原位热脱附过程中土壤温度变化以加热棒为中心,随着距离增加而呈现时间和空间上的滞后效应;原位热脱附设定温度越高,土壤修复效果越好,当土壤设定温度为100℃时,90%土壤样品氯苯去除率达99%以上,与设定温度130℃修复效果相当;土壤粒径越小,其比表面积大,对污染物吸附效率越高,所需热脱附时间越长;含水率影响氯苯在土壤中的挥发速率、有效孔隙率和透气率,含水率过高或过低都不利于氯苯污染土壤原位热脱附修复。热脱附设备设定温度、土壤粒径、土壤含水率对低温原位热脱附技术去除土壤中氯苯的效果具有较大的影响。

In order to investigate the effect of low temperature in situ thermal desorption on chlorobenzene in soil,the chlorobenzene in soil was taken as the target pollutant,and the set temperature of the thermal desorption equipment,soil particle size,soil moisture content were controlled,the chlorobenzene in soil under different conditions was determined and analyzed to study their influences on the thermal desorption effect.The results show that the change of soil temperature was centered on the heating rod during the process of in-situ thermal desorption,and presented the hysteresis effects with time and spatial appear as the distance increased.The higher the set temperature of in-situ thermal desorption was,the better the soil remediation effect was.When the set temperature of the soil was 100℃,the removal rates of chlorobenzene for 90%soil samples were over 99%,which was equivalent to the remediation effect at set temperature of 130℃.For soil with small particle size,it presented a high pollutant adsorption efficiency due to the large specific surface,thus the time for its thermal desorption was longer;The moisture of soil affects volatilization rate of chlorobenzene in soil,and the effective porosity and air permeability of the soil.Too high or low moisture content was not conducive to in situ thermal desorption remediation of chlorobenzene contaminates soil.The set temperature of the thermal desorption equipment,soil particle size and soil moisture content had a great influence on chlorobenzene removal from soil by low temperature in situ thermal desorption technology.