SORPTION AND TRANSPORT OF SULFATE SPECIES IN AN ANION-EXCHANGE MEMBRANE IN CONTACT WITH NA2SO4-H2SO4 SOLUTIONS DETERMINED BY RADIOTRACERS AND RAMAN-SPECTROSCOPY

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