Intensification of nickel recovery from water using an electrically driven hybrid process: continuous electropermutation

Process intensification through the combined use of electrodialysis (ED) and ion-exchange resin (IER) hybrid process, called continuous electropermutation (CEP), was employed to remove Ni(II) cations from water. To carry out this process, Amberjet 1200 H cation-exchange resin was introduced into the feed compartment of the ED cell. The applied electrical field improves the mobility of species and ensures a continuous resin activation which is a main drawback in IER process. Furthermore, the IER incorporated in the ED cell enhances the conductivity of the feed water, therefore it extends the range of ED which could be applied for the recovery of ions from very low concentration wastewaters. The effects of some factors such as the type of regenerating electrolyte, current density, quantity of resin incorporated in the conducting space and concentration of Ni(II) at the inlet were investigated. The efficiency of CEP and ED for Ni(II) removal was expressed in terms of recovery rate and concentration factor. In CEP process, recovery rates of 99% were found with a 40 ppm Ni(II) concentration and an applied current density of 2 mA.cm(-2) resulting in an outlet Ni(II) concentration lower than 1 ppm, against 73.69% in conventional ED. Moreover, in CEP Ni(II) cation was recovered in receiver compartment more than the feed solution with concentration factor more than 10 against 0.39 in ED. On the other hand, the voltage of ED cell was found to increase due to the lower conductivity in the feed compartment compared with that of CEP. In CEP, the highest concentration factor was found at an applied current density of 2.7 mA.cm(-2) which reached 41.26. Finally, with increasing Ni(II) feed inlet concentration, there was a trade-off between obtaining a high Ni(II) concentration in the receiver compartment and a low Ni(II) concentration at the outlet of feed compartment.