Effect of the ionic composition of the accepting solution on the numbers characterizing ionic transport through an ion-exchange membrane: Theoreticalsubstantiation for measuring transport numbers with the hydrodynamic isolation technique

Effect of the composition of an ion-accepting solution on the effective ion ic transport numbers (TN) that are measured with the method of hydrodynamic isolation of the membrane in an asymmetrical system with different composi tions of the ion-releasing and ion-accepting solutions is studied. Electrol yte concentrations and current densities where this effect is the lowest ar e determined. For any arbitrary system, using the releasing and accepting s olutions of different compositions increases the efficient ionic TN through ion-exchange membranes due to an increase in the diffusion flux caused by mutual diffusion at low currents. At a certain current density, TN can be r eferred to the releasing solution and membrane, and are independent of the composition of the accepting solution. Below this current density, the effi cient TN characterize the system as follows from the TN definition.