Effect of functional monomer on synthesis and characterization of ion imprinted polymer for selective separation of Pb (II) ions

Pb(II)-ion imprinted polymer (IIP) was prepared by bulk polymerization of themetal complex of Pb (II) and gallic acid as a ligand, EGDMA as a crosslinker, AIBN as an initiator in ethanol as a porogen. The effect of monomer methyl methacrylate (Pb-IIP-MMA) and 4-vinyl pyridine (Pb-IIP-4VP) which has different alkalinity was investigated due to IIPs performance. As a control, Non Imprinted Polymer (NIP) was synthesized using the same method as IIP without the use of templates. The synthesized polymers were characterized using Atomic Absorption Spectrometry (AAS), Fourier Transform Infrared (FTIR), Scanning Electron Microscope (SEM), and Thermogravimetric Analysis (TGA). Leaching process by 1 M HN03 has no significant effect on IIP structure. Both Pb-IIP-MMA and Pb-IIP-4VP have the optimum adsorption of Pb (II) ion at pH 5 and 90 minutes contact time. The adsorption processes of Pb-IIP-MMA and Pb-IIP-4VP are in accordance with second-order pseudo kinetics with the values of R2=0.8904 and 0.8525 respectively. IIP corresponds to the Freundlich's adsorption isotherm with R2=0.8045 (Pb-IIP-MMA) and 0.8489 (Pb-IIP-4VP). The highest adsorption capacity of Pb (II) 5.92 mg/g was obtained by IIP-4VP. IIP-MMA and IIP-4VP have good selectivity against Cd (II) and Cr (III) interference ion compared to NIP.