Magnetic and hydrophilic imprinted particles via ATRP at room temperature for selective separation of sulfamethazine

In this work, a facile route to prepare hydrophilic molecularly imprinted particles with magnetic susceptibility (MMIPs) was first reported via atom transfer radical precipitation polymerization (ATRPP) in a methanol/water solvent at low temperature (298 K), which can be considered as an environment-friendly system. During the process, 2-hydroxyethyl methacrylate and N, N-methylenebisacrylamide monomers were added to improve the hydrophilicity of the polymers. The obtained materials were characterized in detail by X-ray diffraction, transform infrared spectroscopy, thermogravimetric analysis, vibrating sample magnetometer, scanning electron microscopy and transmission electron microscopy, and then used for the selective separation of sulfamethazine (SMZ) from aqueous medium. The images showed Fe₃O₄ nanoparticles that were successfully embedded into the polymer particles with the size ranging from 450 to 650 nm, which exhibited great superparamagnetic susceptivity and high thermal stability. Batch adsorption experiments were performed to determine specific adsorption equilibrium, kinetics, and selective recognition and separation. The effect of the ratio of the double monomers used in the adsorption property was also studied. The equilibrium data of MMIPs toward SMZ was well fitted by the Langmuir isotherm model, and the maximum adsorption capacity estimated was 66.67 μmol g⁻¹. The adsorption kinetics rapidly achieved equilibrium within 1.0 h and was well described by the pseudo-second-order model. The MMIPs synthesized showed outstanding affinity and selectivity toward SMZ over structurally analogous antibiotics and easily achieved magnetic separation under an external magnetic field. In addition, the adsorption performance of the resulting MMIPs was no obviously decreased at least six repeated cycles.