Preparation and characterization of an ion imprinted polymer for selective separation of Cr(III) ions from water

Abstract

Ion imprinted polymer (IIP) is a technique for creating selectivity through binding cavities on the surface of the adsorbent. The selectivity of polymer adsorbents is based on the coordination geometry, ion coordination numbers, charge, and polymer size. In this research, IIP with chromium ion (Cr3+) as metal template, gallic acid (GA) as ligand, and methyl methacrylate (MMA) as functional monomer was successfully synthesized via bulk polymerization method with ethylene glycol dimethyl acrylate (EGDMA) as crosslinker and azo-bis-isobutyronitrile (AIBN) as initiator. Mole ratio of GA and MMA was observed in this study. The imprinted Cr(III) ion was removed from polymer matrix using 0.1 M HNO3 for 46 h. The structure of Cr-IIP was characterized by FTIR, SEM-EDX and TGA. The optimum absorption of Cr(III) ions was achieved at pH 5 and 120 min contact time. The results indicated that adsorption mechanism followed the Freundlich equation with R2 0.9927 and the maximum adsorption capacity was 170.07 mg/g. The relative selectivity factor of Cr/Fe; and Cr/Ag for IIP is 4.07 and 4.7, respectively. Furthermore, the synthesized Cr-IIP was applied for preconcentration study before analysis of Cr(III) in real sample combined with AAS with % recovery for upstream, middle stream, and downstream are 121.37 %; 110.26 % and 110.87 %.