ELECTRODIALYSIS OF HYDROCHLORIC-ACID

Electrodialysis (E.D.) was not commonly used for the extraction and the reconcentration of acids because the standard anion exchange membranes (A.E.M.) are highly permeable to proton. Recently, special A.E.M. showing a reduced proton leakage have been developed for the recovery of acids by E.D. In this paper, we present a study of E.D. of hydrochloric acid solutions using one of these membranes. The two main parameters which quantify the performances of the process: the current efficiency of HCl removal and the maximum reconcentration level of the acid are analysed on the basis of a transport model. The current efficiency is only determined by the proton leakage through the A.E.M. while the maximum reconcentration level is also determined by the water transport through the two ion exchange membranes.