Transport of Sulfuric Acid in Anion Exchange Membranes

J. Molenat , G. Pourcelly , I. Tugas , C. Gavach
Российский электрохимический журнал
Abstract / Full Text

New commercial anion exchange membranes (AEM) that show a reduced proton leakage have beenspecially manufactured for the recovery of acids. This study deals with the transport properties of these AEMin contact with sulfuric acid solutions. It is divided into two parts: (i) The equilibrium properties; i.e., the AEMare not submitted to any driving force. In this case, measurements of acid sorption, water content, sulfur selfdiffusion flux, electrical conductivity, and data of Raman spectroscopy showed that the AEM cannot beaccounted for by the classical, gel-phase model and that, on the other hand, inside the membrane material, onlythe charges of hydrogenosulfate ions balance the charges of the exchange sites. The apparent individual ionicmobilities are also calculated. (ii) The non-equilibrium properties; i.e., the AEM are submitted to an electricaldriving force. In this case, the measurements of unidirectional fluxes allow the determination of the transportnumber of sulfate species. A proton transfer reaction between the weak basic exchange sites and the hydrogenosulfate ions is suspected to occur.