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The simultaneous recovery of trivalent and tetravalent chromium ions through charged ion-exchange membranes by using three detachable cells was tested at different current densities. The effect of mono- and divalent valence ions corresponding to trivalent and hexavalent chromium ions in the feed phase was investigated. The recovery factor values of chromium (III) and (VI) ion without current density were obtained and found that it was higher in the absence of binary monovalent and divalent ions, but increased with increasing current density and decreased in the presence of the binary mono- and divalent ions. The transport of both oxidation states of chromium ions through membranes was also correlated with the flux data.

The drawback of using the special three compartment cells for both trivalent and hexavalent chromium was demonstrated: recovery increased with an increase of current density and decreased in the presence of co-existent ions in the feed phase. In other words, the recovery of trivalent and hexavalent chromium is more effective in the absence of co-existent ions while the recovery can be improved by using cation- and anionexchange membranes for trivalent and hexavalent chromium ions, respectively.