Abstract
We have already reported that the density and compressibility of particles can be acoustically evaluated, and have proposed a coupled acoustic-gravity field as a potentially useful physical force field. Particles are aggregated at the equilibrium position, which is determined by their acoustic properties rather than by their sizes. These acoustic properties of ion-exchange resins strongly depend on the hydration natures of counterions. Ion-exchange resins with different counterions can thus be discriminated by this acoustic-based field. This approach allows the visual identification of resins and the evaluation of the extent of an ion-exchange reaction.
