Effect of sulfuric acid on electro-electrodialysis of HIx solution

• The electrodialysis of HIx solution was examined for the thermochemical IS process.
• Presence of sulfuric acid in the anolyte did not affect the electrodialysis behavior.
• Presence of sulfuric acid in the catholyte caused formation of a whitish precipitate.
• The sulfur components in the catholyte must be removed prior to the electrodialysis.

The effect of sulfuric acid on the concentration of HIx solution by electro-electrodialysis (EED) was examined for the thermochemical water-splitting iodine–sulfur process. Presence of sulfuric acid in the anolyte HIx solution did not affect the concentration behavior. However, sulfuric acid in the catholyte solution caused side reaction(s) producing whitish precipitates, which indicates that the sulfur compound should be removed prior to the EED operation.