Abstract: The present invention provides an improved process for the regeneration of ion exchange gels and resins. Exhausted regenerating solutions from a either a cationic or anionic exchange column are converted into fresh regenerating solutions via one or a combination of electrodialysis units having at least one bipolar membrane. The spent regenerants may be treated in an electrodialytic water splitter, an acid or base purification unit, or any combination thereof, to reclaim as much or as little of the regenerating solution as is required by the particular process.

Abstract: The present invention relates to a method and an apparatus of electodialytically treating an acid such as citric acid to produce a desired salt of the anion of the acid, such as sodium citrate. A cation can be introduced into a solution via a cheap donor salt solution such as NaCl or KCl, without significantly altering or degrading the purity of the final product. The apparatus comprises a three-compartment cell, which comprises at least two adjacent anion selective membranes to accomplish a cation substitution reaction exploiting the differential selectivities of the adjacent anion membranes employed.