Modeling Surfactant LAS Influenced PAHs Migration in Soil Column

The objective of the present work was to study the transport of Polycyclic Aromatic Hydrocarbons (PAHs) in artificially contaminated and oil field soil columns while Linear Alkylbenzene Sulfonate (LAS) was used as leaching solvent. Through soil column leaching experiments, the through curves (BTCs) of the tracer (Br−) and PAHs were obtained. The batch equilibrium experiments were conducted. The partition coefficients, and the retardation factor (R) were calculated. Nonlinear least-squares optimization approach was used to fit BTCs of Br− and PAHs. The symmetrical BTC for Br− was fitted using equilibrium convention-dispersion equation (CDE) model, and the physical and hydrodynamic parameter, i.e. the dispersion coefficient (D) was calculated. Based on these, the equilibrium and non-equilibrium CDE models were applied to fit the asymmetrical and tailing BTCs of PAHs. Results showed that two-site CDE model is better in fitting the observed data. The concentration distributions of PAHs with leaching time at different depth in the soil column were also estimated using two-site CDE model.