Inspection for the desorption effect and mechanism of petroleum from contaminated soil in surfactant solution

Purpose In order to investigate the desorption effect and mechanism of petroleum from petroleum contaminated soil (PCS) in surfactant solution (SAA-solution). Method In this study, the desorption effect of SAA-solution cleaning of PCS was systematically analyzed by using orthogonal experiments. In addition, the petroleum mechanism of desorption from the PCS surface was further explored by kinetic and thermodynamic studies. Results The results indicated that the petroleum removal efficiency (Re) gradually decreased with the increase of PCS particle size and PCS aging time. The highest petroleum Re was 82.13% under optimum conditions. Subsequently, FT-IR and petroleum component analysis showed the petroleum light components were easily removed from PCS, while the petroleum heavy components limited the desorption of petroleum. The kinetic studies revealed that the petroleum desorption was well depicted by the pseudo-first-order kinetic model, and the desorption rate increased with the decrease of PCS particle size. Meanwhile, the petroleum desorption equilibrium was well described by the Langmuir isotherm model and proceeded by a chemical mechanism. The thermodynamic studies demonstrated that the petroleum desorption from PCS was a viable, spontaneous, and endothermic process. Conclusion The study provided theoretical guidance to apply SAA-solution cleaning industrial PCS. Graphical Abstract