Preconcentration of copper using double-imprinted polymer via solid phase extraction

Abstract

The aim of this study is to prepare double-imprinted polymers which can be used for the selective removal of Cu(II) ions from synthetic waters. Chitosan-succinate (CS) was choosen as the metal complexing polymer. In the first step, chitosan was modified with succinic anhydrides. Modified chitosan was complexed with copper(II) ions and then reacted with 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS). In the prepared imprinted sorbent, both Cu(II) and AAPTS were used as templates. Then polymeric beads were crosslinked with tetraethoxysilane (TEOS). After that, the template (i.e., Cu(II) ions) was removed using 0.1 M HNO3 solution. These Cu(II)-imprinted microbeads were used in the adsorption-desorption process. The effect of initial concentration of metal, the adsorption equilibria and the pH of the medium on adsorption capacity of Cu(II)-imprinting sorbents were studied. The maximum adsorption capacity and the relative selectivity coefficients of imprinted beads for Cu(II)/Zn(II), Cu(II)/Ni(II) and Cu(II)/Co(II) were also calculated. The double-imprinted polymers could be used many times without decreasing their adsorption capacities significantly