Experimental studies were conducted to remove hydrophobic organic compounds (HOCs) from diesel fuel-contaminated soil. Interactions between non-ionic surfactants and diesel fuel were investigated to understand the partitioning effect in heterogeneous soil–water-surfactant systems. The effective critical micellar concentration (CMCeff) was identified from surfactant adsorption, which led to the maximum partitioning of HOCs in the system. This partitioning was attributed to the surfactant (i) lowering the interfacial tension between HOC and soil, (ii) solubilizing HOCs, and (iii) mobilizing HOCs from a solid phase to a pseudo-aqueous phase. The strong adsorption capacity of clay in the soil led to an increase of CMCeff from 20 to 2,500 mg/L of Tween 80. The data for surfactant adsorption and desorption on the soil followed Freundlich’s isotherm and showed irreversible adsorption for surfactant, especially in the presence of clay. The diesel migration from soils to the aqueous phase of surfactant was observed beyond its derived CMC value. The maximum removal efficiency of HOCs could be reached at CMCeff of surfactant due to the higher solubility and competitive adsorption in the presence of clay. Understanding of the soil-surfactant-diesel behavior helped in the effective field implementation of surfactant-enhanced soil flushing for the remediation of oil-contaminated soil.

中文翻译：

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土壤-水系统中表面活性剂和柴油与土壤性质相关的相互作用的评估


进行了实验研究，以从柴油燃料污染的土壤中去除疏水性有机化合物 （HOCs）。研究了非离子表面活性剂和柴油燃料之间的相互作用，以了解非均质土壤-水-表面活性剂系统中的分配效应。从表面活性剂吸附中确定有效临界胶束浓度 （CMCeff），这导致 HOCs 在系统中的最大分配。这种分配归因于表面活性剂 （i） 降低 HOC 和土壤之间的界面张力，（ii） 溶解 HOCs，以及 （iii） 将 HOC 从固相移动到伪水相。粘土在土壤中的强吸附能力导致 Tween 80 的 CMCeff 从 20 mg/L 增加到 2,500 mg/L。表面活性剂在土壤上的吸附和解吸数据遵循 Freundlich 等温线，并显示表面活性剂的不可逆吸附，尤其是在粘土存在的情况下。观察到柴油从土壤迁移到表面活性剂的水相超过其得出的 CMC 值。由于在粘土存在下具有更高的溶解度和竞争性吸附，因此在表面活性剂的 CMCeff 下可以达到 HOCs 的最大去除效率。了解土壤-表面活性剂-柴油的行为有助于有效地在现场实施表面活性剂增强的土壤冲洗，以修复受石油污染的土壤。