Oleic acid removal from ethanolic solutions by ion exchange

Oleic acid uptake from ethanolic solutions was studied at (298.15 ± 0.1) K using a strong anion exchange resin (Amberlyst A26OH). Kinetic data measured at a high stirring rate and different oleic acid concentrations were correlated assuming that the mass transfer resistance is concentrated in the solid phase. In this way it was possible to determine the effective diffusivities of the solute inside the porous structure of the resin. The oleic acid concentration (8–16% by mass) did not influence the calculated values. They were employed as initial estimates for modeling breakthrough data reported on the literature, using the package Chromatography from Aspen Plus software. The selected model takes into account the mass transfer around the resin beads, the axial dispersion in the liquid phase and the diffusion inside the resin phase. The parameter selected for the fitting procedure was the effective diffusivity, so that the values obtained from the modeling of the breakthrough curves and those from the kinetic study could be compared. Both set of values were coherent, varying within the range from (4.5 to 10.2) × 10−12 m2 s−1. This study indicates that the removal of oleic acid from ethanolic solutions using ion exchange is a viable process.

► Ion exchange has good performance in adsorbing oleic acid from ethanolic solutions.
► Measurement of oleic acid effective diffusivity within the anion exchange resin.
► Experimental effective diffusivities not affected by oleic acid concentration.
► Modeling of oleic acid breakthrough curves using Aspen Chromatography.
► Diffusivities obtained by breakthrough modeling compared to the experimental values.