摘要
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SO4^(2-)和Cl^(−)含量分别提高了121.92和49.82 mg·kg^(−1),土壤电阻降低,土壤升温速度呈先快后慢的趋势。设定温度72℃(1,2-二氯乙烷和水共沸点)、加热时间12 h时,污染物去除效果不佳;提高设定温度至95℃,延长加热时间至36 h时,1,2-二氯乙烷去除率可达78.29%~100%。在修复效果的比较上,浅层土壤优于深层土壤;在能量利用率的比较上,间歇加热抽提优于连续加热抽提。污染物性质及土壤对污染物的吸附作用是影响污染物热脱附效果的主要因素,单一污染土壤的1,2-二氯乙烷去除率高于氯苯;在先加入1,2-二氯乙烷后再加入氯苯的复合污染土壤中,氯苯去除率高于1,2-二氯乙烷;老化时间越长,污染物热脱附去除效果越差。本研究结果可为ISERH技术修复氯代烃化工污染场地的工程设计提供参考。
The present research was to study the remediation of chlorohydrocarbon for contaminated soil by insitu 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 SO4^(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.
作者
孟宪荣
葛松
许伟
吴建生
李长宁
MENG Xianrong;GE Song;XU Wei;WU Jiansheng;LI Changning(Suzhou Environmental Science Research Institute,Suzhou 215007,China;School of Environmental Science and Engineering,Suzhou University of Science and Technology,Suzhou 215009,China;Suzhou Nuclear Power Research Institute,Suzhou 215004,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2021年第2期669-676,共8页
Chinese Journal of Environmental Engineering
基金
江苏省环保科研课题(2016061)
苏州市科技发展计划项目(SS201727,SS2019005)。
关键词
原位电阻热脱附
氯代烃
土壤修复
复合污染
in-situ electrical resistance heating
chlorohydrocarbon
soil remediation
combined pollution
