Studies on the effect of functional monomer and porogen on the properties of ion imprinted polymers based on Cr(III)-1,10-phenanthroline complex designed for selective removal of Cr(III) ions

Abstract

New chromium(III) ion-imprinted polymers (IIPs) intended for selective removal of Cr(III) ions from aqueous media were prepared using Cr(III)-1,10-phenanthroline complex as a template by bulk polymerization. The properties of IIPs synthesized using different functional monomers, including acidic (methacrylic acid) and neutral (styrene) agents, polar protic and aprotic porogens (ethanol, acetonitrile) and initiators (2,2′-azobisisobutyronitrile, lauroyl peroxide), were studied in terms of their morphology, sorption properties towards Cr(III) ions, selectivity and reusability. The polymer's particles were characterized using FT-IR, nitrogen adsorption/desorption analysis and scanning electron microscopy. The analytes, Cr(III) ions, were quantitatively retained on the IIPs at pH4.5 and eluted with 0.1molL−1 EDTA solution. Our studies showed that the neutral functional monomer, aprotic solvent and azo initiator provided the best selectivity and sorption properties of IIP. Under optimal conditions, Cr(III)-IIP prepared using ST and AIBN showed good selectivity, reusability and stability. The selectivity coefficient was 16.7, 9.6 and 4.4 for Cr(III)/Cu(II), Cr(III)/Fe(III) and Cr(III)/Mn(II), respectively. Good reproducibility of the results, obtained even after a hundred cycles, testifies to the long-term stability of the sorbents. IIP(4)ST-AIBN can successfully be used as a sorbent in solid phase extraction to selective chromium separation from the water solution.