Electrodialysis (ED) of solutions containing ternary combination of electrolytes (NaCl, KCl, CaCl2, MgCl2, FeCl3)
was carried out. Besides linear velocity of the fluid flowing through the ED cell, physical properties of cations
and their interaction with the gel phase of membrane significantly influenced ion transport. The role of concentration
polarization was evaluated from limiting current density (LCD) measurement. Theoretically estimated
LCD values based on effective diffusivity of each ions and mass transfer coefficients (Sherwood number, Sh correlation)
satisfactorily (error ± 5–7%) predicted experimental data. Measurement of transport number, adsorption
equilibrium, water uptake and membrane resistance were carried out for each composition to understand
the role of cations—membrane equilibriumin ion transport. Cationswith higher charges showed reduced transport
number, higher adsorption and higher resistance over cation exchange membrane (CEM). Water uptake
measurement of equilibrated CEM showed negligible difference when cations of similar charges were
interchanged while a meager 1.5% variation was noted when cations of different charges were interchanged.