Maxwell-Stefan modeling of mass transfer in solvent impregnated resins

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 R2>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.