Synthesis and characterization of Fe(III)-ion imprinted polymers (Fe-IIPs) as selective sorbents with Alizarin Red-S and 2-vinylpyridine

Iron (Fe) is an essential trace element that requires monitoring and removal when it acts as a pollutant. Previous studies have demonstrated limited selectivity in separating Fe(III) from complex sample matrices. To overcome these drawbacks, in this study Fe(III)-Ion Imprinted polymers (Fe-IIPs) were synthesized as selective sorbents with Alizarin Red-S as a ligand and 2- Vinylpyridine as a functional monomer. Bulk polymerization was carried out with Trimethylolpropane trimethacrylate (TMPTMA) as a crosslinker. Fe(III) ions were eluted with an HNO3 solution to create the template. Non-Imprinted Polymers (NIPs) prepared without an imprinted ion, served as controls. The synthesized Fe-IIPs were characterized by FTIR (spectra), SEM (morphology), and EDX (elemental content). The effects of contact time, pH, and initial concentration were studied. Adsorption equilibrium was reached within 30 minutes. The maximum adsorption capacity of Fe-IIPs was 134.224 mg g-1 at pH 5. The adsorption isotherm of Fe-IIPs conformed to the Langmuir model, while the kinetic adsorption data fitted the pseudo-second order model. The selectivity coefficient for Fe(III) ions relative to interfering ions exceeded unity, indicative of the imprinting effect.