Permselectivity of Ions Through the Ion Exchange Membranes

When there is a distribution of electrical potential, W, in the system, the electrochemical potential of cation A is expressed by rjA, that of anion X as rjx, and that of solvent (water) by i/w 

When the ion exchange membrane equilibrates with the outer solution (j/f membrane phase), 

for standard conditions of each component, cation A and anion X and water, at 1 atm in infinite dilution, 

The electrical potential generated between membrane and solution phases, the Donnan potential, is derived from Eqs. (2.17) and (2.18), 

When a mole of electrolyte dissociates into vA mol of cation A and vx mol of anion X, 

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