【作者】 殷甫祥；

【导师】 林玉锁； 封克；

【作者基本信息】 扬州大学 ， 环境科学， 2010， 硕士

【摘要】 土壤气相抽提技术（Soil Vapor Extraction ,SVE）是一种广泛应用于去除土壤中挥发性有机物（VOCs）的原位修复技术。通过模拟SVE通风处理苯单一污染土壤及甲苯、乙苯、正丙苯和苯、甲苯、乙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、不同土柱直径、不同土壤粒径和不同污染物种类等因素对模拟了SVE通风效率的影响。结果表明,当土壤污染物只有苯这一种时,通风流量仅需0.03 L·min^-1即可在10h内进入拖尾期,去除率达到99%以上;当柱径14 cm、土壤粒径为10目,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;相同土壤装填量,不同柱径,通风流量0.15L·min^-1条件下,柱底面积/装土高度（S/H）越大,去除率越高;土壤粒径由10目变为20-40目后,土壤密实度增加,非水相液体（Non-aqueous Phase Liquids, NAPLs）与气相间的传质系数降低,SVE效率降低;另一组实验研究了通风流量为0.1L·min^-1、0.2L·min^-1和0.3L·min^-1条件下对黄棕壤中苯、甲苯、乙苯的去除效率,结果表明,苯、甲苯、乙苯分别在12h、18h、24h内都进入拖尾期,TVOCs去除率分别达到99.52%和99.55%,通风流量为0.1L·min^-1时就能很好地去除土壤中的污染物。比较通风流量为0.15L·min^-1和0.10L·min^-1时的通风效率后分析可知苯环上碳原子数越多,沸点升高,饱和蒸气压降低,使得挥发性减弱,且饱和蒸气压低的正丙苯对土壤中甲苯、乙苯脱附和挥发的阻碍作用明显,导致甲苯、乙苯、正丙苯污染的土壤更难净化,故VOCs的分子结构和性质也是影响污染物去除效率的重要因素。更多还原

【Abstract】 As an in situ remediation technology, soil vapor extraction （SVE） has been widely used to remove volatile organic compounds （VOCs） from soil. In order to find the optimum conditions of removing volatile organic compounds （VOCs） from soil by soil vapor extraction （SVE） technology. Through simulated the ventilation process of SVE, some parameters such as the different continuous ventilation, the different soil water content and intermittent aeration,the diameters of soil columns, soil particle size and different types of pollutants have been studied on restoring yellow brown soil contaminated by benzene and two groups of toluene, ethylbenzene, n-Propylbenzene and benzene, toluene, ethylbenzene. The results showed that when the soil contaminants only one kind of benzene, it was get into tailing stage within 10h and the removal efficiency of benzene was more than 99% at 0.03 L·min^-1 ventilation flow rate ;the ventilation flow rate and soil water content were two important factors on SVE, and they both had the best values.When the column diameter was 14cm, the soil particle size of 10 mesh, continuous up-flow rate of 0.15L·min^-1 and water content about 17.98%, the removal efficiency of toluene, ethylbenzene, n-Propylbenzene and TVOCs amounts to 99.84%,99.45%,98.25% and 99.30%, The repairing effect is best and superior to intermittent ventilation. When soil water content is 6.01% 24.73% the removal efficiency of TVOCs only amounts to 63.03% and when soil water content is 24.73% the removal efficiency of TVOCs only amounts to 89.03%. The results showed that water content which is too high or too low is disadvantageous to the removal of VOCs.The other results showed that the larger bottom area /soil height （S/H） , the better efficient when different column diameter and the same weight of soil loading; soil particle size is 20-40 mesh, soil density increased, non-aqueous phase liquids （ NAPLs） and gas phase mass transfer coefficient decreased, SVE efficiency will be reduced; Another group of experiments study on the removal efficiency of benzene, toluene, ethylbenzene in yellow brown soil when the ventilation flow rate are 0.1L·min^-1 and 0.2L·min^-1. The results showed that benzene, toluene, ethylbenzene are get into tailing stage within 12h ,18h and 24h respectively, and the removal efficiency of TVOCs amounts to 99.52% and 99.55%. The pollutants can be removed very well When the ventilation flow rate is 0.1L·min^-1. After compared with the efficiency of ventilation flow of 0.15L·min^-1 and 0.10L·min^-1 knows that the longer branched chain on benzene ring, the higher boiling point, the lower saturated vapor pressure and the less volatile, furthermore, toluene and ethylbenzene are desorbed and hindered significantly by n-Propylbenzene which is lowest saturated vapor pressure and make toluene, ethylbenzene and n-Propylbenzene polluted soil more difficult to purify. Molecular structure and property are the important factors which also affect the pollutants removal efficiency.更多还原