Micellar extraction: removal of copper(II) by micelle-solubilized complexing agents of varying HLB using ultrafiltration

The hydrophobic core of micellar systems can solubilize hydrophobic extractants in a way similar to the organic solvent in a classical solvent extraction. In this paper it is demonstrated that micellar extraction can be as effective as solvent extraction and shows the same characteristic features (effect of pH, effect of the hydrophilic/lipophilic balance (HLB) of the extractant, extractant concentration, etc.). A series of 6-[(alkylamino)methyl]-2-(hydroxymethyl)pyridines (CnNHMePyr with n = 4, 8, 10, 12, 14, and 16) are used for this purpose in combination with CTAB and C12EO6 micelles. The removal of copper(II) is achieved by ultrafiltration. A simple model is developed on the basis of equilibrium relations to theoretically predict the yield of copper extraction.