气相抽提法（SVE）去除土壤中挥发性有机污染物的试验研究

通过模拟土壤气相抽提技术（Soil Vapor Extraction,SVE）通风处理甲苯、乙苯、正丙苯混合污染的黄棕壤,研究了不同通风流量、不同土壤含水率、间歇通风等因素对目标污染物去除率的影响。结果表明,通风流量和含水率是影响去除率的重要因素。当柱径14 cm、土壤粒径为10目连续通风时,最佳通风流量为0.15 L.min-1,最佳含水率约17.98%条件下,甲苯、乙苯、正丙苯的去除率分别为99.84%、99.45%、98.25%,总挥发性有机物（Total VOCs,TVOCs）去除率达到了99.30%,且优于间歇通风;含水率为6.01%、24.73%时,TVOCs的去除率仅为63.03%、89.03%,表明含水率过高或过低都不利于VOCs的去除;苯环上支链越长,分子量越大,沸点越高,越难以被脱附去除,反之亦然,表明有机物的分子结构和大小也是影响通风效果的重要因素。

Soil Vapor Extraction（SVE）to Remove Volatile Organic Compounds in Soil

Soil vapor extraction（SVE）has been widely used to remove volatile organic compounds（VOCs）from soils as an in-situ reme-diation technology.Simulated ventilation study has been carried out in a laboratory for a yellow brown soil contaminated with toluene,ethyl-benzene and n-propylbenzene.Effects of ventilation rate,soil moisture content and time interval between aeration on removal effeciency of contaminants had been investigated.The results showed that the ventilation rate and soil moisture content were two key factors influencing re-moval rate of VOCs by SVE.Removal pencentages of 99.84%,99.45%,98.25% and 99.30% for toluene,ethylbenzene,n-propylbenzene and total VOCs,respectively,were observed under the following experimental conditions：a column diameter of 14 cm,tested soil being passed through a 10 mesh sieve,a continuous up-flow rate of 0.15 L.min-1 and soil moisture water content at about 17.98%.The removal rate of VOC under continuous aeration was generally higher than under the intermittent aeration.At higher or lower soil moisture contents of 6.01% or 24.73%,the removal efficiency of total VOCs amounts to 63.03% or 89.03%,which indicated negtive effects of soil moisture content at too high or too low levels.A general trend was that molecular structure and size of benzene series were also important factors influencing remedi-ation efficiency of VOCs.Longer branched chain on benzene ring,greater molecular weight and higher boiling point would lead to more diffi-cult decontamination of VOCs from soils.