Abstract：
Electro-osmosis has been well recognized as a technique for the remediation of petroleum-contaminated soil, however seasonally freezing and thawing adds the complexity of petroleum mobility in cold regions. To investigate the influence of freeze-thaw on the electroosmotic removal of petroleum and explore the enhancement of freeze-thaw on the electroosmotic remediation efficiency in remediating the petroleum-contaminated soils, a set of laboratory tests were performed in three types of treatment modes, freeze-thaw (FT), electro-osmosis (EO) and freeze-thaw combined electro-osmosis (FE). The petroleum redistributions as well as the moisture content changes after the treatments were evaluated and compared. The petroleum removal rates of the three treatments were analyzed, and the underlying mechanisms were elaborated. The results indicated that the overall efficiency of the treatment mode regarding petroleum removal from soil followed the order of FE > EO > FT, corresponding to 54%, 36% and 21% in maximum, respectively. A considerable amount of water solution with surfactant was driven into contaminated soil during FT process, but the petroleum mobilization primarily occurred inside of the specimen. A higher remediation efficiency was yield in EO mode, but the induced dehydration and cracks leaded to the dramatical depression in the efficiency in further process. It is proposed that the petroleum removal is closely related to the flow of water solution with surfactant that is favorable to the solubility and mobilization of the petroleum in soil. Thus, the water migration induced by freeze-thaw cycles substantially improved the efficiency of the electroosmotic remediation in FE mode that gave the best performance for the remediation of the petroleum-contaminated soil.
摘要：
电渗已被公认为是一种修复石油污染土壤的技术，然而，季节性的冻融增加了寒冷地区石油流动性的复杂性。为了研究冻融对石油电渗去除的影响，探讨冻融对石油污染土壤电渗修复效率的增强作用。在三种类型的治疗模式下进行了一组实验室测试，冻融(FT),电渗(EO)和冻融联合电渗(FE)。对处理后的石油再分布以及水分含量变化进行了评估和比较。分析了三种处理的石油去除率,并阐述了基本机制。结果表明，该处理模式对土壤中石油去除的总效率遵循FE>EO>FT的顺序，相当于54%，36%和最大21%，分别。在FT过程中，大量含有表面活性剂的水溶液被驱入污染的土壤中，但是石油动员主要发生在标本内部。EO模式下的修复效率更高，但是诱导的脱水和裂缝导致进一步加工效率大大降低。提出石油的去除与表面活性剂水溶液的流动密切相关，这有利于石油在土壤中的溶解和动员。因此，冻融循环引起的水分迁移大大提高了FE模式下电渗修复的效率，从而为石油污染土壤的修复提供了最佳性能。
