Solvent impregnated resins are promising for the removal of polar organic compounds from aqueous streams, but have low mass transfer rates. A thorough understanding of the phenomena occurring inside the pores of the solvent impregnated resin is therefore required. In this study a mathematical model was developed to describe the simultaneous diffusion and reaction. The diffusion was described using the Maxwell Stefan approach towards multi component diffusion and included the volume expansion of the organic phase. The model was validated using experimental data from the literature on the extraction of phenol by Cyanex923 impregnated in macro-porous polypropylene. The model described the experimental data as function of temperature and initial concentration accurately with an R-2 > 0.96 and a regressed reaction rate constant with a confidence interval of +/- 6%. Analysis of the model results revealed that multi-component effects as described by the Maxwell-Stefan model were of limited importance whereas the volume expansion was essential to accurately describe the experimental data. (C) 2015 Elsevier Ltd. All rights reserved,