Competitive transport of Zn(II), Cd(II), and Cu(II) ions from aqueous chloride source phase (c_Me=0.01M) through polymer inclusion membranes (PIMs) containing cellulose triacetate (support), o-nitrophenyl pentyl ether (plasticizer) and side-armed lariat ether-type derivative of diphosphaza-16-crown-6 (ion carrier) has been investigated. The influence of the group attached type to the PNP-lariat ether molecule on the selectivity and efficiency of Zn(II), Cd(II), and Cu(II) transport through polymer inclusion membranes is studied. The removal of metal ions by transport through PIM’s from acid aqueous phase into 0.1 M CH₃COONH₄, NH₄OH or EDTA aqueous solution (receiving phase) is presented. The selectivity coefficient of Cd/Zn and Cd/Cu decreases with Cl^- concentration increase in source phase for transport with bis-lariat ether, whereas for mono-lariat ether the selectivity coefficients are not changed.