Abstract
In this review, we discuss the various facets of ion-exchange phenomena as well as approaches thereto mainly on the basis of our research work. The approaches stated here include ion-exchange chromatography, capillary electrophoresis, X-ray absorption fine structure (XAFS), ion transfer voltammetry at a liquid/liquid interface, a coupled acoustic-gravity filed etc. Ion exchange chromatography has been principally used as a practical tool but is also an efficient tool for evaluating ion-exchange selectivity. However, results have been analyzed in an improper way, which practically gives convenient information but possibly incorrect physical views. This has been partly overcome by introducing electrostatic models into the interpretation of ion-exchange chromatographic retention data. Similar models have proven effective in the discussion of the ionic partition into molecular aggregates such as micelles and surface monolayers. Finally, an acoustic method is discussed as a tool for a dynamic study of ion-exchange. Although an acoustic force is usually a function of the sizes of particles, size effects can be eliminated when a gravity force is incorporated. In this coupled acoustic-gravity field, we can visually resolve the acoustic properties of an ion-exchange resin particle, which are varied by the progress of ion-exchange.
