【摘要】 用阳离子表面活性剂十六烷基三甲基溴化铵(HDTMA-Br)和阴离子型表面活性剂十二烷基苯磺酸钠(SDBS)对黄土进行改性处理,并制备了一系列土壤样品。比较了甲苯在天然黄土和改性土中的不同吸附特性,并探讨了它们不同的吸附机理。通过比较甲苯在两类土壤中的吸附特性可以发现,等温吸附曲线均符合弗德里希方程式,但改性黄土的吸附能力为天然黄土的3~6倍。当同时用阴-阳离子表面活性剂进行黄土改性,吸附能力比单独使用阳离子表面活性剂改性的黄土增强15%~20%。土柱实验证明改性黄土对有机污染物对硝基苯胺的迁移具有明显的滞后性,使污染带前锋到达土柱出水口的时间延迟了50倍,也使土柱被穿透的时间延长了3.5倍。可见用表面活性剂对黄土改性能有效地在包气带滞留污染物,在一定程度上延缓或防止地面石油泄漏对含水层的污染。更多还原

【Abstract】 Both cationic surfactant hexadecyltrimethylammonium bromide(HDTMA-Br) and anionic surfactant sodium dodethylbenzene sulfonate(SDBS) were used to modify a series of loess samples.The sorption characteristics of toluene on the natural and modified soils were compared and the adsorption mechanisms were investigated.Through the comparison of toluene adsorption in two kinds of soils,it was found that all the isothermal adsorption curves fitted the Freundlich equation,but the adsorption capacity of the modified loess was enhanced by 3～6 times. Moreover,loess soils coated with anion-cation surfactants had a higher adsorptive capacity by 15～20% than corresponding single-cation organosoils.The column tests proved that the time interval for the contaminant plume front in the modified soil reached the outlet was delayed by 50 times longer than the natural loess.Meanwhile,the retardation capacity of the HDTMA-modified soil for p-nitroaniline solution to breakthrough was enlarged at least 3.5 times greater than the natural loess.It is evident that modification of loess with surfactants can significantly hold up the petroleum pollutant migration within the vadose zone,which will,to certain extent,release or prevent groundwater contamination from petroleum leakage.更多还原