Transfer of H2SO4, Na2SO4 and ZnSO4 by dialysis through an anion exchange membrane

Competitive diffusion between H2SO4 and its salts (Na2SO4 and ZnSO4) was performed using a Neosepta AFN anion exchange membrane. The stronger affinity of sulfuric acid and the higher mobility of protons in the membrane with respect to sodium and zinc cations explain the great difference in the diffusivity between acid and salts through this membrane. Coexisting sodium and zinc sulfates have no significant effect on H2SO4 diffusion flux, ion content and electrical resistance. The results are analyzed with acid sulfuric solutions on the basis of the Nernst-Planck equation and Goldman hypothesis. Calculated values are compared with experimental values. This work shows that diffusion dialysis allows one to recover sulfuric acid from effluents containing sodium and zinc ions.