The application of polymer inclusion membranes based on CTA with 1-alkylimidazole for the separation of zinc(II) and manganese(II) ions from aqueous solutions

Abstract

Polymer cellulose triacetate membranes doped with 1-alkylimidazole as fixed carriers were applied for the investigation of the facilitated transport of Zn(II) and Mn(II) ions from an aqueous sulphate feed phase (c M = 0.001 mol/dm 3 ). For the polymer inclusion membranes (PIMs) doped with 1-alkylimidazole (alkyl - from hexyl up to decyl), the following patterns of transport selectivity were found: Zn(II) > Mn(II). The highest initial flux of Zn(II) ions (2.65 μmol/m 2 ·s) was found for PIMs doped with 1-decyl-imidazole, whereas the best Zn(II)/Mn(II) selectivity coefficients equal to 19.7 were found for 1-hexyl-imidazole. Permeability coefficients for Zn(II) and Mn(II) ions transported across PIMs increase with an increase in the pK a values of 1-alkylimidazole. The polymer membranes of cellulose triacetate-o-NPPE with 1-alkylimidazole were characterised by scanning electron microscopy, non-contact atomic force microscopy and thermal analysis techniques. The influence of membrane morphology on the Zn(II) and Mn(II) transport process was discussed.