Cr(VI) transport through ceramic ion-exchange membranes for treatment of industrial wastewaters

This work is devoted to assessment of the possibility of using ceramic membranes, which contain an ion-exchange component, such as hydrated zirconium dioxide (HZD), for Cr(VI) removal from dilute solutions by electrodialysis. Transport properties of the membranes were investigated. HZD-containing membranes were found to be permeable to anions in acidic media while they demonstrate cation-exchange properties in alkaline media. Cr(VI) anion transport through HZD membranes was studied. It was shown that an increase in the amount of ion-exchanger in the membrane results in a rise in electrodialysis efficiency. The transport number of Cr(VI) species was found to range from 0.33 to 0.63 for currents below the limiting current. It was also shown that increasing the concentration of H⁺ or Cr(VI) ions in the solution to be purified allows higher rate of Cr(VI) ion transport through the membrane.