流化床式低温等离子体降解土壤中六氯苯的实验研究  

Study on the degradation of hexachlorobenzene in contaminated soil by fluidized-bed non-thermal plasma

作　　者：屠璇 张硕[1] 刘振[1] 闫克平[1] TU Xuan;ZHANG Shuo;LIU Zhen;YAN Keping(Institute of Industrial Ecology and Environment,College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学化学工程与生物工程学院工业生态与环境研究所,杭州310027

出　　处：《浙江大学学报（农业与生命科学版）》2022年第3期351-358,368,共9页Journal of Zhejiang University:Agriculture and Life Sciences

基　　金：国家重点研发计划项目(2019YFC1805604)。

摘　　要：针对土壤中难降解的六氯苯,开展了流化床式介质阻挡放电反应器对其降解特性的实验研究。结果表明:介质阻挡放电过程中产生了20μs脉宽的脉冲电流。空气流速为4.0 L/min时,土壤达到充分流化状态。增加放电电压会提高反应器的能量密度,有利于六氯苯的降解,但发热会导致能量利用率降低。当放电电压增至16 kV、能量密度为172.5 J/L、放电32 min时,六氯苯降解率达到97.3%。相较于酸性土壤,中性或碱性土壤对六氯苯的降解更有利。提高土壤中六氯苯的初始含量会使其降解率降低,但绝对去除量增加。六氯苯的降解符合一级动力学方程,放电过程中C—Cl键受到活性物质攻击而断裂,生成了低取代氯苯和小分子有机酸等副产物,表明土壤中六氯苯的降解过程以脱氯为主。该结果对实现高效修复实际污染土壤具有重要的现实意义。To study the degradation of hexachlorobenzene(HCB)in contaminated soil by dielectric barrier discharge(DBD),a fluidized-bed DBD reactor was used to degrade HCB in contaminated soil.The results showed that a discharge current pulse could be generated with a 20μs pulse width.When the air flow rate was 4.0 L/min,the soil reached a fully fluidized state.The energy density of reactor increased with the increase of discharge voltage,which promoted HCB degradation,but increasing heating led to lower energy utilization.The HCB degradation rate reached 97.3%after 32 min while the energy density was 172.5 J/L at a discharge voltage of 16 kV.The neutral or alkaline condition was more beneficial to HCB degradation than the acidic condition.With the increase in the initial HCB concentration,the degradation rate of HCB decreased,but the absolute degradation amount increased.The degradation of HCB conformed to first-order kinetic equation.During the discharge process,the C—Cl bond was attacked by active substances,and low-substituted chlorobenzene and small molecular organic acids and other byproducts were generated,which indicated that the degradation of HCB in contaminated soil was mainly a dechlorination process.The research results have important practical significance for the remediation of actual contaminated soil.

关 键 词：六氯苯 介质阻挡放电 脉冲放电 降解 

分 类 号：X53[环境科学与工程—环境工程]