Methyl parathion imprinted polymer nanoshell coated on the magnetic nanocore for selective recognition and fast adsorption and separation in soils

Core-shell magnetic methyl parathion (MP) imprinted polymers (Fe3O4@MPIPs) were fabricated by a layer-by-layer self-assembly process. In order to take full advantage of the synergistic effect of hydrogen-binding interactions and π-π accumulation between host and guest for molecular recognition, methacrylic acid and 4-vinyl pyridine were chosen as co-functional monomers and their optimal proportion were investigated. The core-shell and crystalline structure, morphology and magnetic properties of Fe3O4@MPIPs were characterized. The MP-imprinted nanoshell was almost uniform and about 100 nm thick. Binding experiments demonstrated that Fe3O4@MPIPs possessed excellent binding properties, including high adsorption capacity and specific recognition, as well as fast adsorption kinetics and a fast phase separation rate. The equilibration adsorption capacity reached up to 9.1 mg/g, which was 12 times higher than that of magnetic non-imprinted polymers, while adsorption reached equilibrium within 5 min at a concentration of 0.2 mmol/L. Furthermore, Fe3O4@MPIPs successfully provided selective separation and removal of MP in soils with a recovery and detection limit of 81.1-87.0% and 5.2 ng/g, respectively.