Synthesis of ion imprinted polymeric nanoparticles for selective pre-concentration and recognition of lithium ions

Abstract

This work reports the preparation of lithium ionimprinted polymer materials using benzo-12-crown-4 as a selective crown ether, methacrylic acid (MAA) as a functional monomer, ethyleneglycol dimethacrylate (EGDMA) as a crosslinker, and 2,2′-azobisisobutyronitrile (AIBN) as a radical initiator. The imprinted lithium ion was removed from the polymeric matrix using a 1.0 mol L⁻¹ HNO₃ solution. The resulting sorbent was characterized using scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) theory, X-ray diffraction (XRD) and IR spectroscopy. The prepared particles have a diameter of 50–60 nm which results in the fast recognition of lithium ions. The maximum adsorption capacity and pre-concentration factor of the prepared particles were 1019.27 μmol g⁻¹ and 100, respectively. The Li⁺-imprinted sorbent was reused ten times without a significant decrease in binding affinity. The relative standard deviation (RSD%) and the limit of detection were evaluated to be 2.1% and 3.29 μg L⁻¹, respectively. Finally, the resulted IIP particles showed high selectivity toward lithium ions over some foreign metal ions with selectivity coefficients above 18.5.