Dialysis applied to the selectivity study of cation exchange membranes in contact with strong electrolytes

Preliminary tests allowed us to improve an experimental device and to defin e a measurement protocol leading to a choosing criterion among different me mbranes through leakage flux determinations. This method presents the advan tages of being simple, accurate and allows a continuous monitoring of the l eakage process through ion exchange membranes by measuring the conductivity in the downstream compartment. For well-defined experimental conditions (e lectrolyte nature and concentration), the electrolyte flux determination al lows one to classify different membranes by their selectivity. The higher t he membrane selectivity, the lower the electrolyte leakage. From one membra ne to another, the electrolyte flux variations are considerable. Thus, a cl assification through the electrolyte leakage method seems to be more accura te than other methods such as the counter-ion transport number determinatio n.