Description of intraparticle diffusional sorption and desorption processes in ion-exchange sorbents

All general effects of ion exchange kinetics can be considered within the framework of a nonlinear phenomenological diffusional model. According to the model, the dependence of intraparticle diffusivity D on the concentration of sorbed (desorbed) ion a is unknown beforehand and, in general, it should be determined from the experiments by solving the so-called inverse problem. Hence, the work considered some important features of this model relating to the sorption–desorption processes.