甲苯在典型土壤中的迁移性能

Migration Property of Toluene in Typical Soils

采用一维土柱装置模拟非水相液体(NAPLs)在我国两种典型土壤(北京潮土与湖南红壤)中的垂向迁移过程,以甲苯为例研究了其在两种土壤中的迁移性能;采用XRD技术测定土壤的矿物组成。实验结果表明,当潮土和红壤孔隙率均为45%时,甲苯在潮土中的迁移速率和最终迁移距离均显著高于在红壤中。甲苯在潮土中的阻滞系数(Rf=18.9)小于在红壤中(Rf=26.5),表明红壤对甲苯的吸附阻滞作用强于潮土。XRD表征结果显示,红壤中粒径小的黏粒含量较高,具有较多的黏土矿物,对甲苯具有更强的吸附阻滞能力,致使甲苯在红壤中垂向迁移速率小,最终迁移距离较短。

Taken toluene as an example, the vertical migration processes of non aqueous phase liquids （NAPLs） in two typical soils named fiuvo-aquic soil and red soil in China were studied using a one dimension soil column. The mineral composition of soil was determined by XRD. The experimental results show that when the porosities of fluvo-aquic soil and red soil are all 45%, the migration rate and the stable migration distance of toluene in fluvo-aquic soil are faster and longer than those in red soil. The adsorption and retardation effect of red soil is significantly larger than that of fluvo- aquic soil, which may be explained by the higher value of retardation coefficient （Re） of red soil （Re =26.5 ） compared to that of fluvo-aquic soil （Rf=18.9）. The XRD characterization results show that the red soil has higher content of clay with small size and more clay mineral with stronger adsorption capability to toluene, resulting in the slower migration rate and shorter stable migration distance of toluene in red soil.