Abstract
By applying sequentially the same experimental procedure formerly developed and based on the Nernst–Planck approach, it was possible to reconstruct the electrodialytic (ED) recovery of trisodium citrate.
The membranes exhibited an almost ideal behaviour and only the citrate anions carried the electric charge passing through the anionic membranes. By performing several voltage-current, electro-osmosis and desalination tests, it was possible to assess in sequence the limiting electric currents and resistances of the anionic and cationic membranes, the transport numbers for anion and cation in the solution and membranes, and for solute and water. Whereas the electric resistance (Rc) of the cationic membranes was found to be approximately constant (0.15 ± 0.06 ?) and independent of solute concentration, that for the anionic ones was not only greater than Rc, but also a logarithmic function of the solution electric conductivity in D compartment. Provided that the current applied was less than 2/3 of the limiting current corresponding to the cationic membrane (Ilim,c,) the basic engineering parameters enabled the time course of the voltage applied to the ED stack to be reconstructed with a mean percentage error of 17.5%.
