Hyperbranched polyester having nitrogen core: synthesis and applications as metal ion extractant

Hyperbranched polyesters, based on 2,2-bis(hydroxymethyl)propionic acid as an AB, monomer and triethanol amine as a core molecule were synthesized and characterized with C-13{H-1} NMR spectroscopy and size exclusion chromatography. The sorption behavior of the hyperbranched polyester systems containing the oxygen ligating sites towards ions such as Cu(II), Co(II), Ni(II), Cd(II), Zn(II), Pb(II) and Fe(III) was studied for the first time. The efficiency of binding (EOB) of the system for the seven metal ions was found to be in the range of 0.6-26.0 moles of metal ions per mole of the polyester, indicating good potential of some of them for metal extraction. The optimum pH range for the maximum extraction of metal ion was found to be 5.0-7.0 for Cu(II) and Pb(II), 4.5-7.0 for Fe(III), 6.0-8.0 for Co(II) and Ni(II), 6.0-7.5 for Cd(II) and 6.5-8.0 for Zn(II). The hyperbranched polyesters were found to be fully efficient for the extraction of these metal ions at 10 ng ml(-1) concentration level. (C) 2004 Elsevier B.V. All rights reserved.