Résumé
The ionic composition of a polymeric anion exchange membrane and the transport number of sulfate ions through this membrane are determined when it is in contact with mixed Na2SO4-H2SO4 solutions.
The amount of sorbed species and the transport numbers are obtained by the radiotracer method. Sorption results combined with those of Raman spectroscopy allow the ionic composition of the membrane material to be obtained.
The sulfate/hydrogen sulfate ratio increases with the salt content of the equilibrating solution. For very low acid contents, the transport number of the sulfate ion reaches unity while it does not exceed 0.85 for the same acid concentrations in the absence of sodium sulfate.