有機物在土壤-水-界面活性劑系統中之分佈情形曾引起廣泛的重視，因為所獲得的結果除將影響有機物在環境中之傳輸與宿命外，同時也是以界面活性劑復育受污染土壤的重要參考依據。一般認為界面活性劑之種類、土壤性質與有機物之水溶解度為決定其分佈最主要的參數，在本研究中參照上述參數並以一系列之實驗探討Kd值與Kd*值之變化解釋這些參數所產生的影響。 界面活性劑可增加有機污染物在水相中的溶解度，也可吸附於土壤上增加土壤有機質含量使有機物脫附困難，陽離子界面活性劑與土壤間的作用機制主要為電荷引力，因此土壤的陽離子交換能力(CEC)是最主要的影響因子，且其容易於表面形成吸附性微胞導致污染物傾向分佈於土壤；影響非離子界面活性劑吸附於土壤的主要因子為土壤無機相性質；包括電荷間斥力、凡得瓦爾力、與氫鍵等皆會影響陰離子吸附，因其吸附機制複雜所以目前尚未能獲得一具體結論。 由研究結果顯示，土壤有機質含量愈高，以界面活性劑復育愈困難，其主要原因在以分佈形式存在於土壤有機質中污染物較難被脫附。高水溶解度有機物在土壤-水-界面活性劑系統中其分佈行為主要受到土壤有機質與吸附於土壤上界面活性劑性質之影響，因此界面活性劑對土壤之吸附特性為決定其吸脫附之重要因子；低水溶解度的有機物在此系統中容易受到溶液性質之影響，界面活性劑在溶液中形成微胞可明顯增加污染物自土壤上脫附。綜合上述因子以陰離子界面活性劑、針對低有機質土壤、低水溶解度污染物將是提高脫附效率的最佳選擇。 Distribution of organic contaminants in soil-water-surfactant system has been an important issue in recent years. The distribution coefficients determine the fate and transportation of contaminants in the environments. Also, the efficiency of soil remediation by surfactant washing could be evaluated via the contaminant distribution coefficients. The objective of this study is to evaluate soil remediation efficiency using surfactant washing on the basis of surfactant properties, soil properties and contaminant solubility. The normalized value, Kd*/Kd, was used to elucidate the remediation efficiency under the above operation conditions. In this research, prior to finding the relation between the soil properties and the surfactant adsorption characteristics, as a guide to proper surfactant selection and the best concentration for maximum performance, is necessary. Cationic surfactants tended to be strongly adsorbed to soils and clays via the electrostatic interactions and thus the adsorption capacities were directly proportional to the CEC values of the examined solids. The anionic surfactant sorption is related to the van der Waals force or hydrogen bonding for clay surface. The adsorption of nonionic surfactants usually showed a correlation with the soil mineral properties. For the relatively water-soluble compounds, the surfactant adsorption on the soil surface is the dominant factor determining the desorption capacity. For the less-soluble compounds, the existence of micelles in the solution leads to significant contaminant desorption. The contaminants partitioning to the SOM or the adsorbed surfactants causes a relatively poorer desorption efficiency. Anionic surfactants do not form admicelle on soil surface to significantly enhance SOM. Thus, the anionic surfactant to remedy low solubility compounds on low SOM soil is the best choice.
