The determination of diffusion coefficients of counter ion in an ion exchange membrane using electrical conductivity measurement

Electrical conductivity experiments were carried out in a bi-ionic (chloride–nitrate) electrolyte with and without a permselective anion exchange membrane (ACS of Tokuyama Soda) at variable chloride/nitrate concentration. Diffusion coefficients of counter ions (Cl− and NO3−) in the membrane were determined from a mathematical model based on the Nernst–Planck diffusion–convection theory: the mean diffusion coefficients in the membrane were obtained by fitting the (conductivity vs. concentration) curves with the Nernst–Planck equation.