Reactions and transport modeling of surfactant and anthracene in the soil flushing process

Soil flushing using surfactants is a promising alternative to the pump-and-treat method of removing hydrophobic organic compounds. The interactions and transport modeling of the surfactant and chemicals in soil were studied by batch and column experiments. Sodium dodecylsulfate (SDS), an anionic surfactant, and anthracene, a hydrophobic organic, were chosen as a representative surfactant and chemical for the soil flushing process. The equilibrium model was observed to predict the SDS breakthrough in soil columns. Mobilization of anthracene from soil matrices by flushing medium containing SDS was noted to be a rate-limiting process. A non-equilibrium model was found to be suitable for the prediction of anthracene breakthrough. The quasi-equilibrium isotherm between anthracene in SDS solution and the soil appeared to be of the Langmuir type.