Continuous electropermutation with ion-exchange textiles

A continuous electropermutation process using ion-exchange textiles has been developed in order to eliminate cations from low concentration solutions. The applied voltage was used simultaneously as the driving force for extracting the cations and regenerating the ion-exchange textiles. Due to their sheet form and swelling in aqueous solutions, these ion-exchange materials provide a good contact with ion-exchange membranes. This process was tested with NaCl solutions under various experimental conditions; then it was applied to treate a solution containing metal ions such as Zn2+. The study carried out with a laboratory pilot developing an active membrane area of 20 cm(2) showed that the process is able to achieve high levels of removal (>95%) and to concentrate cations in small volumes of the receiving compartment. The presence of ion-exchange textiles in the feed compartment of the ED stack allows a lower power consumption than with conventional electrodialysis.