| 摘要 |
Procedure for the isolation and purification of free acids from the salts thereof by electrodialysis by means of a set of cells with 4 compartments, formed by stacking anionic membranes alternately with cationic membranes, with a proton-generating solution being recirculated through A, water or a dilute solution of the acid to be isolated being recirculated through B, an aqueous solution of the salt of the acid to be isolated being recirculated through C, and an aqueous solution of a salt being recirculated through D, characterized in that both the anolyte and the catholyte are made up of an aqueous solution of a salt of the same composition in both cases, and in that when a difference in potential is applied between the electrodes, migration of the ions occurs, so that a pure free acid is obtained in compartment B. The procedure allows free acid to be obtained without co- existing with its salt in the same compartment, which increases the purity thereof. The procedure is suitable for purifying a large number of acids, especially iminodiacetic acid (IDA). <IMAGE>
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