$Fe^{3+}$ imprinted polymeric systems

Abstract

The ion-imprinting is a technique which is prepared using metal ions and binding with high crosslinking for the preparation of adsorbents for the separation of metal ions. Ion-imprinted materials are easy to prepare, stable, inexpensive and capable of molecular recognition. The aim of this study is to prepare an ion-imprinted polymer, which can be used for the selective removal of $Fe^{3+}$ ions. Chitosan-succinate was chosen as the complexing monomer, $Fe^{3+}$as template and epichlorohydrin was chosen as crosslinking agent. In the first step, chitosan was modified with succinic anhydrides and complex formation occured between carboxylic acid functional groups and $Fe^{3+}$ ions. Secondly, $Fe^{3+}$ - chitosan-succinate polymer was crosslinked with epichlorohydrin. After that, the template ($Fe^{3+}$ ions) was removed using 0.1 M HCl solution and the $Fe^{3+}$ -imprinted polymer was used in the adsorption-desorption process. Molecular cavity for the $Fe^{3+}$ ion was obtained in the $Fe^{3+}$-imprinted polymer. The maximum adsorption capacity has found to be 78.2 mg/g. Adsorption equilibrium was achieved in about 60 min. The relative selectivity coefficients of imprinted polymers for $Fe^{3+} /Al^{3+}$ and $Fe^{3+}/Mn^{2+}$ were 5.13 and 4.0 times greater than non-imprinted matrix, respectively. It should be noted that the $Fe^{3+}$ -imprinted polymer could be used many times without decreasing the adsorption capacity significantly.