Salt ions move along field orientation in constant electric field. Thus the principle of solution electroneutrality is met at any field point. Ion-exchange membranes represent polymer films, have fixed ionogenic groups trapping and exchanging ions (counterions). Membranes in electrolytic solutions are electron conduction-free, i.e. they act as electrolytic conductors, not bipolar electrodes.
The principle of multichamber electrodialysis is concluded in placement of a set of separated alternating cation-exchange and anion exchange membranes between two electrodes. So, demineralized and concentrated solutions flow in the formed chambers. The transfer process in such a system is repeated for many times that allows to reduce dramatically relative losses of energy on electrodes. Appplication of the principle of multichamber electrodialysis made it possible to design compact electrodialyzers with a big surface of membrances.
Efficiency and quality of used membranes is of utmost priority in electrodialysis process. In addition to chemical stability, mechanical strength and stable size ion-exchange membrane shall have a high selective ability, good current conductivity, revers diffusion small rate and low osmotic permeability within the working range of compositions and solution concentrations.
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