Application of Shrinking-Core Model for Ionization of Hydrophobic Ionic Beads

Abstract

AbstractA model based on the pseudo-steady-state shrinking core for the ionization of PMMA/MAA beads is presented. This accounts for the film mass transfer, intraparticle diffusion, and chemical reaction resistances in series. The film mass transfer resistance plays a minor role in the overall ionization process for the range of experiments studied herein. The specific reaction rate constants and diffusion coefficients increase as the pH of phosphate buffer increases, due to the increased accessibility of hydroxide ion and increased swelling of the gel layer, respectively; the specific reaction rate constants and diffusion coefficients are little influenced by the change of ionic strength of the phosphate buffer. The model shows that the rate of ionization depends upon the concentration of the buffer solution.