Adsorption behavior of metal ions on alkylhistidine extractant impregnated resins: Effect of functional groups of histidine

Two types of alkylhistidine extractants, histidine-2-ethylhexyl amide (His-EH) and N-p-tert-octylphenoxyacetyl-histidine (OP-His) were prepared. The alkylhistidine extractants were impregnated onto a methacrylate-based polymer support to investigate the adsorption selectivity for metal ions. His-EH, which has coordinating imidazole and amino groups, adsorbs Cu(II), Ni(II), Zn(II) and Co(II) at pH > 5. By contrast, OP-His, which has imidazole and carboxyl groups, shows adsorption selectivity; Cu(II) > Zn(II) > Ni(II) > Co(II). A column was packed with OP-His impregnated resin to investigate the separation selectivity between Cu(II) and Co(II). Cu(II) was selectively adsorbed and was efficiently concentrated to 59 times the concentration of the feed solution. (C) 2013 Elsevier B.V. All rights reserved.