Application of the Maxwell–Stefan Approach to Acrylonitrile Adsorption and Desorption in a Macroporous Polymer

Abstract

This article reports the application of the Maxwell–Stefan approach for multicomponent liquid-phase diffusion in a macroporous polymer. The adsorption of acrylonitrile onto Dowex Optipore L-493 from water and its desorption from the sorbent in different water/acetone mixtures was modeled. The intraparticle diffusion is treated as diffusion in a nonideal bulk fluid since the pores of the sorbent are large and the molecules–pore wall interactions can therefore be neglected. The results of the simulations are in good agreement with the experimental data. The Maxwell–Stefan intraparticle diffusion coefficients are in the same range as the free liquid diffusion coefficients according to Fick. The calculation of the thermodynamic factors shows that, whereas for low acrylonitrile mole fractions in water, Fick’s diffusion can give good results, the nonideality of the system has to be taken into account for higher acrylonitrile concentrations.