粉砂介质包气带中甲苯蒸气挥发的迁移转化  

Migration transformation of toluene vapor in silty sand soil vadose zone

作　　者：龚亚炬 宋云 李培中 魏文侠 

机构地区：[1]轻工业环境保护研究所,北京100095

出　　处：《环境工程学报》2018年第1期206-212,共7页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(41201516);环保公益性行业科研专项(201409047)

摘　　要：挥发性有机物通过包气带向上迁移到地表或室内引发的蒸气入侵(vapor intrusion,VI)问题越发受到关注。以甲苯作为研究对象,采用土柱实验,对粉砂介质包气带中甲苯蒸气发生的扩散、生物降解的规律进行研究。结果表明,粉砂介质中,甲苯蒸气扩散穿透70 cm土柱时间为24 h,甲苯蒸气在土柱内扩散10 d时,土柱达到短暂的稳态平衡;12~30 d时,处于动态平衡;30~60 d时,土柱内甲苯蒸气浓度下降速率发生变化,土柱内O_2体积分数下降了8%,CO_2体积分数增加了6%;60 d时,甲苯蒸气基本被降解。说明覆盖一定厚度的粉砂对甲苯蒸气的迁移有比较好的阻滞和生物降解作用。The problem of vapor intrusion（VI）caused by volatile organic compounds （VOCs） which migrate to the surface or indoors through vadose zone has been paid more and more attention. To study the diffusion and biodegradation regularity of toluene vapor in silty sand soil vadose zone, a soil column experiment was carried out. The results showed that toluene vapor could penetrate 70 centimeter soil column in 24 h, while the soil col- umn reached a short steady-state balance at 10 days. It reached a dynamic balance between 12 and 30 days. There would be a shift on the decreasing rate of toluene vapor concentration in the soil column between 30 and 60 days, and the volume fraction of O2 in the soil column decreased by 8% , while the volume fraction of CO： in- creased by 6%. After 60 days, toluene vapor degradation had basically been completed. The results showed that silty sand with certain thickness could effectively retard migration of toluene vapor and beneficial for its biodegradation.

关 键 词：蒸气入侵 甲苯蒸气 扩散 生物降解 

分 类 号：X53[环境科学与工程—环境工程]