Selective copper(II) sorption behavior of surface-imprinted core-shell-type polymethacrylate microspheres

Core-shell-type metal ion-imprinted polymer microspheres (MIIPs) were prepared. The shell layer was established on the surface of the polystyrene core via novel precipitation polymerization of ethylene glycol dimethacrylate (EGDMA) and copper methacrylates (Cu(MAA)2). The prepared microparticles showed a very narrow size distribution from 2.5 to 3.2 μm, depending on the amount of the dispersing medium. The size, structure, and zeta potential of the MIIP particles were investigated using scanning electron microscopy (SEM) and a zeta meter. The MIIPs showed an excellent selective separation capability for the target Cu(II) ion over other ions possessing the same ionic valence number, such as Ni(II), Cd(II), and Mg(II). The elapsed time to adsorption equilibrium was very short, and the adsorption capacity increased with pH up to the saturation of 70% at pH 5.6. The MIIP microspheres exhibited a much higher separation capacity and selectivity for the target imprinted ion than non-MIIP.