Zinc(II) selective removal from other transition metal ions by solvent extraction and transport through polymer inclusion membranes with D2EHPA

An experimental investigation concerns zinc(II), cobalt(II), nickel(II), copper(II) and cadmium(II) ions separation from aqueous chloride solutions by solvent extraction and transport through polymer inclusion membrane (PIM) processes. The selective transport of metal ions from the aqueous chloride source phase through PIM containing cellulose triacetate (support), o-nitrophenyl pentyl ether (plasticizer) and di(2-ethylhexyl)phosphoric acid (ion carrier) is shown. Zn(II) can be effectively removed from dilute aqueous chloride solutions by its transport through PIMs with di(2-ethylhexyl)phosphoric acid as the ionic carriers into 1.0 M HCl as the receiving phase. The transport selectivity of Zn(II) over Co(II), Ni(II), Cu(II) and Cd(II) decreases while the pH of the solution increases in the source phase. Also, by solvent extraction, Zn(II) can be selectively removed from dilute aqueous chloride solutions.