PRODUCTION OF SULFURIC-ACID AND CAUSTIC SODA FROM SODIUM-SULFATE BY ELECTROMEMBRANE PROCESSES - COMPARISON BETWEEN ELECTROELECTRODIALYSIS AND ELECTRODIALYSIS ON BIPOLAR MEMBRANE

In order to generate H2SO4 and NaOH from Na2SO4 solutions, the electro -electrodialysis (EED) and the electrodialysis (ED) on bipolar membran e (BPM) are compared. For both these processes, the electroosmosis ass ociated to the transport of the sodium ions through the cation exchang e membrane (CEM) limits the soda concentration. Due to the co-ion leak ages through the BPM which increase with the concentrations of the aci d and the base on both sides of this membrane, the current efficiencie s of both the acid and the base production are higher for the EED than for the ED on BPM. However, the investment cost for EED is higher tha n for ED due to the need for a couple of metallic electrodes per each elementary cell.