Mutual Separation of Vanadium and Tungsten from Aqueous Solution via Electrochemical Reduction and Sorption onto Chelating Resin

The possibility of mutual separation of V and W oxoanions from aqueous solution was investigated by elecro-reduction of V(V) to V(IV) in a flow-type electrolyzer combined with column sorption on a selective resin having l-deoxy-l-(methylamino)-glucitol functional groups. At pH 3, V(V) oxoanion (VO(3)(-)) was reduced to V(IV) cation, which passed into the effluent, whereas W, existing as WO(4)(2-), was quantitatively retained by the resin. In this way, complete separation of V and W was achived. By elution with 1 M HCl, the V(IV) in a form of VO(2+) was eluted. Tunsgten was eluted quantitatively with 1 M NaOH. A co-removal and co-elution of V with W was observed, which is supposed to be due to V(IV)/W heteropolyanion formation during the electro-reduction..