Publications

The effect of successive limiting current density (LCD) determination procedures on electrodialysis with ultrafiltration membrane (EDUF) system was studied in order to evaluate their impact on ion-exchange (IEM) and ultrafiltration membranes (UFM) integrity by measuring in situ the membrane potential difference. In the first protocol, two successive LCD determination procedures were carried-out by increasing the voltage by 2 V from 0 to 40 V, spaced by a rest period of 60 min. In the second protocol, the LCD determination procedures were performed every 20 min during 60 min. For both protocols, voltage–current curves were plotted for IEM and UFM and I_lim values were determined. Results showed that only anion-exchange membrane (AEM) showed a typical sigmoidal curve for both protocols. Moreover, it was demonstrated that a rest time period of 60 min between two successive LCD determination procedures had no impact on system current density and membrane potential difference while four successive LCD determinations spaced by a constant rest period of 20 min allowed delaying the appearance of I_lim and over-limiting current region. A mathematical sigmoid-model approach was also proposed allowing for the first time the calculation of the different parameters typical of water splitting phenomenon from a voltage–current curve.