AbstractIn this study, sorption and the transport mechanism of surfactants in clayey soil was examined. The adsorption and desorption isotherms for sodium dodecyl sulfate (SDS) and biosurfactant (UH‐biosurfactant) with sand and kaolinite were quantified. Kaolinite clay had the highest sorption capacity compared to blasting sand. Miscible displacement breakthrough experiments were done in order to determine the transport parameters. Transport parameters such as the dispersion coefficient (D) and the retardation factor (R) of the above‐mentioned surfactant solutions were determined in clayey soils [sand (82.5 %) and kaolinite (17.5 %) mixture] with and without ionic strength. In this study 0.1 g/L NaCl was used as the electrolyte solution. A two‐region transport convective–diffusive model was used to model the breakthrough curves of the surfactants. This model resulted in excellent descriptions of the data. Bromide ions were chosen as the tracer material in order to characterize the column. Perchloroethylene (PCE) is used in various kinds of industrial and commercial applications. SDS and UH‐biosurfactant were used to flush the PCE contaminated soil. UH‐biosurfactant solubilized more PCE compared to that of SDS in contaminated soils.