Effect of Tween surfactant components for remediation of toluene-contaminated groundwater

The objectives of this study were to select potentially suitable surfactants that solubilize toluene present as a contaminant and to determine the effectiveness of toluene removal from groundwater by the selected surfactants. Four different surfactants of Tween series were chosen based on surfactant types, toxicity, HLB (Hydrophilic-Lipophilic Balance), CMC (Critical Micelle Concentration). In the separatory funnel experiments, Tween 20 was not able to solubilize at least 1 mL of toluene and was considered ineffective. Tween 40, Tween 60 and Tween 80 were relatively good toluene solubilizers. The highest recovery (98%) of the toluene was obtained using a nonionic surfactant (Tween 60) in the batch experiments. In Tween series surfactant, the trend of ionic strength magnitude in sampled groundwater was closely related with that of recovery rates. The ionic strength of aqueous phase had a strong effect in aqueous activity. The aqueous activity was decrease when ionic strength was increased. The test methods employed may be useful for rapid selection of surfactants and are essential for reducing cost in surfactant-assisted remediation. Also, these selected surfactants are expected to be in practical use for remediation of toluene-contaminated groundwater.