Preparation And Performance Of Graphene Oxide-Based Magnetic Imprinted Polymers

Graphene oxide and metal-organic frameworks are both nanomaterials with large specific surface areas.Graphene oxide has excellent physical and chemical characteristics and can be stably dispersed in aqueous solution.The metal organic framework is an excellent nano-adsorption material with adjustable pore size.Graphene oxide is used as the substrate to prepare grapheme oxide-based functional materials and grapheme oxide/metal materials.The organic frame composite material is a support material for imprinted polymers,which not only improves its adsorption capacity and specific selection recognition effect,but also improves the polymer to overcome the defects of easy stacking of graphene sheets and combines the advantages of metal organic frames.In this paper,three grapheme oxide composite-based magnetically imprinted polymers are synthesized based on graphene oxide materials.Combined with chromatographic analysis,inductively coupled plasma emission spectroscopy,ultraviolet spectroscopy,and solid-phase extraction techniques,the magnetically imprinted polymers prepared are applied to large enrichment,separation and detection of copper and lead ions in molecular proteins and environmental water samples.The main work of this paper was shown as follows:?1?A facile protein imprinted polymer?M-MIPs?based on magnetic rich-amine mesoporous silica/graphene oxide was synthesized using dopamine as the functional monomer and bovine hemoglobin as the template molecule.Innovatively,Fe₃O₄nanoparticles coated with amino was introduced onto graphene oxide by an inverse microemulsion method for facilitating surface polymerization dopamine imprinted layer.The protein adsorption tests showed that the imprinted layer with an optimized ratio of magnetic rich-amine mesoporous silica/graphene oxide,dopamine and bovine hemoglobin can significantly shorten theadsorption equilibrium time of the M-MIPs toward bovine hemoglobin.The adsorption equilibrium time of the M-MIPs toward bovine hemoglobin was 40 min.Under optimized conditions,the imprinting factor of the M-MIPs toward bovine hemoglobin was 2.09 and the maximum adsorption capacity was 164.5 mg g^-1.Several experimental parameters,including temperature and p H of solution,type and volume of elution solvent,washing solvent,extraction time were investigated in detail.The recoveries of the bovine hemoglobin in spiked bovine calf serum samples were ranged from 84.6%to102.5%.?2?A type of magnetic ion-imprinted polymer?M-IIPs?based on magnetic graphene oxide/MIL-101?Cr?was synthesized with surface imprinting technology using magnetic graphene oxide/MIL-101?Cr?as the supporting materials,Cu???and Pb???as templates,dopamine as the functional monomer.The morphology,particle size,and magnetic properties of the M-IIPs were characterized by Fourier-transform infrared spectroscopy,vibrating sample magnetometer and scanning electron microscope.The adsorption kinetics,isothermal adsorption performance and adsorption selectivity of M-IIPs toward Cu???and Pb???were investigated in detail.The results showed that the M-IIPs have a superior adsorption performance toward Cu???and Pb???with the maximum adsorption capacity of 144.92 mg g^-1 and 322.58 mg g^-1,respectively.The magnetic solid-phase extraction conditions were optimized in detail.The M-IIPs was successfully used for the separation and detection of trace amounts of Cu???and Pb???in water samples.The recoveries of Cu???and Pb???were 81.99?89.91%and81.24?95.15%,respectively.?3?In this study,a green and facile three-dimensional magnetic molecularly imprinted polymer?DES-3DMMIPs?based on new-type three-dimensional magnetic graphene oxide/MIL-101?Cr?with eco-friendly deep eutectic solvent monomer was prepared through the surface grafting copolymerization technique for the selective recognition and separation of bovine hemoglobin.The morphology and structure property of the DES-3DMMIPs were characterized by scanning electron microscopy,Fourier-transform infrared spectrometry and the vibrating sample magnetometer.The adsorption experiment of the DES-3DMMIPs toward bovine hemoglobin was investigated in detail.The influences of the concentration of bovine hemoglobin,adsorption time,incubation p H,solution ionic strength on the adsorption performance of the DES-3DMMIPs were discussed.The maximum adsorption capacity of DES-3DMMIPs was calculated as 173.31 mg g^-1 with the imprinting factor of 3.03.The adsorption equilibrium was reached quickly within 20 minutes.Furthermore,DES-3DMMIPs can extract bovine hemoglobin from bovine blood successfully with the recoveries of 85.2?108.7%.