SORPTION AND SEPARATION OF DIVALENT METALS BY A MACROMOLECULAR RESIN CONTAINING ORGANOPHOSPHORUS ACIDS

Studies have been conducted on the equilibrium distribution of divalent zinc ion between aqueous solution and macromolecular resin impregnated with phosphoric acid bis(2-ethylhexyl ester) (D2EHPA). The mechanism of Zn(II) sorption on the impregnated sorbent is different from that for the solvent extraction, being expressed by a simple ion-exchange reaction, with the equilibrium constant of 0.036 kg of sorbent/dm3. The separations of Zn(II)/Cu(II) using D2EHPA-impregnated sorbent and of Co(II)/Ni(II) by the resin impregnated with (2-ethylhexyl)phosphonic acid mono(2-ethylhexyl ester) (EHPNA) have also been conducted in a batch operation. It was found that the selective sorptions of Zn(II) to Cu(II) and of Co(II) to Ni(II) can be attained satisfactorily with the separation factors of 55.2 and 6.73, respectively.