Selective separation of cobalt using a new Co(II)-imprinted polymer/cryogel system

Abstract

The aim of the present study was to investigate selective separation and preconcentration of Co(II) ions in aqueous solutions by ion imprinted technique. For this purpose, Co(II)-methacryloylhistidine((MAH)2-Co(II)) complex monomer has been synthesized and polymerized with presence of 2-hydroxyethyl methacrylate (HEMA) followed by flushed out of bonded Co(II) ions from polymer with 5.0 mol*L-1 HNO3. Thus, specific cavities for re-binding of target ions (Co(II)) have been created onto p-HEMA-MAH cryogel column. Prepared metal complex and Co-imprinted polymer/cryogel system have been characterized by FTIR and SEM. The effect of various parameters such as pH, initial concentration, flow rate, ionic strength have been investigated to determine optimal adsorption conditions. The maximum amount of adsorbed Co(II) has found as 106.0 mg*g-1 at pH 8.0 with flow rate of 1 mL*min-1. For selectivity experiments, binding studies were carried out presence of Cu(II) and Ni(II). The k (selectivity coefficient) values have found as 8.9 and 3.8 for Co(II)/Cu(II) and Co(II)/Ni(II) binary mixture, respectively. The reuse of column also has been investigated and there was no significant decrease at adsorption capacity even in consecutive eleven experiments.