||Surfactant-Enhanced Solubilization of Residual Dodecane in Soil Columns. 2. Mathematical Modeling.
Abriola, L. M. ;
Dekker, T. J. ;
Pennell, K. D. ;
||Michigan Univ., Ann Arbor. Dept. of Civil and Environmental Engineering.;Robert S. Kerr Environmental Research Lab., Ada, OK.;Ford Motor Co., Dearborn, MI.
Surface active substances ;
Mathematical models ;
Soil chemistry ;
Porous materials ;
Soil columns ;
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A mathematical model is developed to describe surfactant enhanced solubilization of nonaqueous phase liquids (NAPLs) in porous media. The model incorporates aqueous phase transport equations for organic and surfactant components as well as a mass balance on the organic phase. Rate-limited solubilization and surfactant sorption are represented by a linear driving force expression and a Langmuir isotherm, respectively. The model is implemented in a one-dimensional Galerkin finite element simulator which idealizes entrapped residual organic as a collection of spherical globules. Soil column data for the solubilization of residual dodecane by an aqueous solution of polyoxyethylene (20) sorbitan monooleate are used to evaluate the conceptual model. Input parameters were obtained, where possible, from independent batch experiments. Calibrated model simulations exhibit good agreement with measured effluent concentrations, supporting the utility of the conceptual modeling approach. Sensitivity analyses explore the influence of surfactant concentration and flushing strategy on NAPL recovery.