原位电阻热脱附修复氯代烃污染土壤

针对原位电阻热脱附(ISERH)技术基础性研究不足、缺乏小试设备研发等问题,利用自主研发ISERH设备,以1,2-二氯乙烷和氯苯为目标污染物,探究了ISERH过程中土壤温度变化及设定温度、加热时间、污染物种类、老化时间对污染物热脱附效果的影响.结果表明,在热脱附过程中氯代烃污染土壤的主要阴离子SO42-和Cl-含量分别...

Remediation of chlorohydrocarbon contaminated soil by in-situ electrical resistance heating

The present research was to study the remediation of chlorohydrocarbon for contaminated soil by in-situ electrical resistance heating (ISERH) with independent designed ISERH equipment due to the lack of basic research and development of laboratory scale test equipment of ISERH. 1,2-dichloroethane and chlorobenzene were selected to be targeted contaminants to study the effects of temperature, heating time, pollutant species and aging time on the removal efficiency of contaminants during the ISERH process. The results showed that the content of ${rm{SO}}_4^{2 - }$ and Cl− in chlorohydrocarbon contaminated soil increase 121.92 mg·kg−1 and 49.82 mg·kg−1 respectively during ISERH process, resulting in a reduction of soil electric resistance, and a fast followed by slow tendency of soil temperature. Contaminants could not be removed effectively when temperature was at azeotropic point 72 ℃ and heat for 12 h. Whereas the 1,2-dichloroethane removal efficiency increased to 78.29%~100% when the temperature increased to 95 ℃ and heating time lengthened to 36 h. In the aspect of remediation effect, shallow soil layer was superior to deep soil layer. And on the energy-efficient side, the manner of intermittent heating and extraction possess an advantage over the continuous mode. Contaminant nature and absorption between contaminant and soil are the main factors affecting removal efficiency. The removal efficiency of 1,2-dichloroethane is higher than chlorobenzene, while which is invers in the combined pollution soil of pre-filled 1,2-dichloroethane and post-added chlorobenzene. The longer the aging time, the worse the thermal desorption efficiency. The experimental results can provide references for the engineering design of ISERH technology to industrial site remediation of chlorohydrocarbon.