Non linear transport of sorbitol in ion exchange membranes during electrodialysis

Abstract

Polyatomic alcohol sorbitol is widely used in food and pharmaceutical industry as a sugar substitute.
In industry sorbitol is produced by hydrogenation of D-glucose. At the stage of purification of an aqueous
solution of sorbitol is necessary to remove sodium salts from the solution. The most effective method of
demineralization is electrodialysis. The purpose our work was researching of the regularities of the sorbitol
electromigration through the ion exchange membrane in a wide range of current densities.
The obtained results show that the linear dependent of sorbitol fluxes from current density is keeped
until the limiting diffusion of current density. In case of excessing limiting current density was registered the
decreasing of the mannitol fluxes which was connected with a recharge of cations in anions and anions in
cations on the boundary ion exchange membranes – electrolyte solution. Through the further increasing of
current density it was observed the increasing of the mannitol fluxes as a results of the conjugating mannitol
fluxes with hydrogen and hydroxyl ions. The best effect of demineralization of sorbitol was achieved with a
slight excess of the limiting diffusion current density.