LAUSR

The formation of cadmium(II) complexes with hydrophobic 1-alkylimidazoles (1-hexylimidazole (1), 1-heptylimidazole (2), 1-octylimidazole (3), 1-decylimidazole (4)) was tested by liquid–liquid partition method. On the basis of the extraction data, stability constants of cadmium(II) and Pb(II) complexes were determined. It had been assumed that differences in the formation of cadmium(II) and lead(II) complexes with alkylimidazoles could be used to separate those ions. The possibility of cadmium(II) and lead(II) ion separation in the transport through polymer inclusion membranes (PIMs) was examined. PIMs comprising of cellulose triacetate, o-nitrophenylpentyl ether, and alkylimidazole (1-4) were used. The membranes were characterized using atomic force microscopy (AFM). The results have shown that cadmium(II) ions are effectively transported through PIMs. The best result achieved for cadmium(II) removal from Cd(II)–Pb(II) solution for PIMs with (4) was 95.5% after 24 h. For this membrane, the separation coefficients for Cd(II)/Pb(II) were 1.62. Best Cd(II)/Pb(II) selectivity coefficients equal to 2.94 were found for (1). The influence of the basicity of carrier molecules on transport kinetics was discussed as well.