The facilitated transport of Zn(II), Cd(II), Co(II), and Ni(II) ions from different aqueous chloride source phases (c(Me) = 0.001 mol/dm(3), pH = 6.0) across supported (SLMs) and polymer inclusion membranes (PIMs) doped with 1-decyl-4-methylimidazole as ion carrier was reported. The membrane is characterized by means of atomic force microscopy (AFM). The results show that Zn(II) can be separated very effectively from other transition metal cations as Cd(II), Co(II), and Ni(II) from different equimolar mixtures of such ions. The higher initial fluxes for Zn(II) were found for PIM (3.62-4.10 mol/m(2).s), while the lower values were observed for SLM. However, after taking into account the morphology (porosity, tortuosity) of the membranes, the values of the initial flux of Zn(II) transport across the PIM are lower than those across the SLM. The recovery factor of Zn(II) ions during transport across PIM and SLM from different mixtures of cations is above 95% after 24 hrs. PIM containing 1-decyl-4-methylimidazole are stable for 120 hrs.