Modeling the transport of sulfuric acid and its sulfates (MgSO4, ZnSO4, Na2SO4) through an anion-exchange membrane

• Selectivity of membrane Selemion AAV in mixtures of H2SO4 and its salts was studied.
• Leakage of cations (Mg2 +, Zn2 +, Na+) on the AAV anode side in electrodialytic process
• Model of the H2SO4-sulfate transport through an anion-exchange membrane
• Association M·SO4 in the sulfate transport through AAV should be taken into account.

The separation of sulfuric acid from its sulfates (MgSO4, ZnSO4, Na2SO4) by the electrodialytic method was investigated. The weak-basic anion-exchange membrane Selemion AAV was used. It was found that the current efficiency of anion transport (HSO4−, SO42 −) was independent on the kind of metal cation present on the cathode side of membrane. Despite the presence of the external electric field acting against the concentration force, the permeability of metal cations to the anode side of AAV in the electrodialytic process was close to that in a diffusive one. The developed transport model based on the Nernst–Planck equation and Donnan equilibria satisfactorily described the permeation of acid. To describe suitably the transport of metal sulfates, the assumption about their full dissociation is insufficient and the metal cation–sulfate anion association should be taken into account.