Remediation Of Contaminated Soil With Polycyclic Aromatic Hydrocarbons (PAHs) By Single And Mixed Surfactants

Surfactant Enhanced Remediation (SER) has been widely used to control the pollution of polycyclic aromatic hydrocarbons (PAHs) in soil. In this work, the two types of gemini anionic surfactant AGS and traditional nonionic surfactants including Tween-80, TritonX-100 and Brij35 were chosen in order to obtain the environmentally friendly and economic surfactant remediation technology. The desorption of phenanthrene and naphthalene in soil by single and mixed surfactant systems has been studied. The impact of temperature, ionic strength, molar ratios and their interactions on the flushing of PAHs have been discussed further, ultimately determining the optimal experimental conditions and providing a preliminary proposal. The adsorption of Tween-80, TritonX-100 and Brij35 have been analyzed. Besides, it has been conducted about the comparison of desorption efficiency by the nonionic and gemini surfactant systems. The adsorption of nonionic surfactants increased with the concentration of surfactant. It indicates that:the balance is achieved at the certain points and the sorption isotherms of surfactants are fitted by Langmuir model. The desorption efficiency of AGS is higher than Brij35 and lower than Tween-80 and TritonX-100. The efficiency of phenanthrene and naphthalene by AGS is 94%,79% respectively. The presence of naphthalene effectively enhances the solubilization of phenanthrene in mixed compounds. A study of remediation of contaminated soil with PAHs by AGS and Brij35 mixed surfactants has been determined. The remarkable effect of temperature on the desorption of phenanthrene in soil has been observed. The significance of three factors follows the order:temperature>ionic strength >molar ratios by variance analysis. The optimal conditions are chosen as temperature of 25℃, molar ratios of 1:3, and ionic strength of 50 mg/L. In a word, the normal temperature, low levels of ionic strength and higher proportion between AGS and Brij35 will improve the flushing of PAHs in soil, and can effectively save the costs of surfactant.