Preparation And Properties Of Magnetic Functional Nanomaterials

Magnetic hybrid nanoparticles have superparamagnetism from magnetite and special properties from polymer parts,such as biocompatibility,stimuli-responsivity,fluorescence,and the dispersion of hybrid nanoparticles,are obviously improved compared to that of magnetite.The research of magnetic hybrid nanoparticles have been intensively pursued because of their potential application in biomedicine,catalysis,separation and other fields.In this paper,this dissertation focuses on the preparation,structure characterization,morphology characterization,catalytic properties,and recycling performance of ferroferric oxide-based magnetic nanomaterials,and develops different preparation methods,different catalytic targets,and composition of ferroferric oxide-based magnetic polymers.The synthesis,magnetic separation performance and catalytic performance of the material were studied;specifically as follows:?1?Fe₃O₄ nanoparticles were prepared by chemical co-precipitation,The Fe₃O₄@OA nanoparticle was abtainedby surface-modifying with oleic acid.PVI-Pd?II?@Fe₃O₄@OA were prepared via precipitation polymerization in supercritical carbon dioxide.The catalytic properties of magnetic polymer to reduce the methylene blue were studied.PVI-Pd?II?@Fe₃O₄@OA materials showed excellent catalytic performance in the reduction of methylene blue with sodium borohydride as reducing agent.Typically,the polymer–metal complexes exhibited higher catalytic activity whenmolar ratio of VIm:Pd?II?=4:1.The catalysts could be easily recycled by an external magnetic field and reused without obvious activity loss even after repeated the catalytic experiments for 15 times.Magnetic nanocomposites also exhibit good catalytic reduction of 4-NP.?2?Magnetic nanoparticles with uniform particle size were prepared by solvothermal method.The surface were coated with silica and functionalized with vinyltriethoxysilane.Precipitation polymerization in scCO₂.the prepared polymer magnetic nanoparticles are used for loading cobalt with different contents,and the prepared cobalt-loaded magnetic nanocomposites are used for catalysis.The methyl orange?MO?was degraded to investigate the catalytic performance of MO at different pH values and the catalytic properties of different nanocomposite magnetic nanocomposites.Experiments show that the composite has the best catalytic effect on the degradation of the azo dye MO at pH=2.5;this magnetic nanocatalyst can be reused five times and the catalytic activity is kept well.The orange yellow G and methyl red containing only one azo group in the dye molecule have excellent catalytic degradation performance,of which the degradation of Congo red can reach 86.42%;double the amount of catalyst under the same experimental conditions can also achieve the Congo The red is completely degraded.?3?Magnetic nanoparticles with uniform particle size were prepared by solvothermal method.The surface of the magnetic nanoparticles was coated with RF and a magnetic colloidal crystal template was prepared by vertical precipitation method.Magnetic macroporous carbon was prepared by using the magnetic colloidal crystal template.The hard templating template supported by the opal structure was prepared by injecting an acidic titania precursor?tetrabutyl titanate?using a space-limited solvent volatilization to induce self-assembly.The magnetic titania nanospheres with controllable thickness of the titanium dioxide shell were prepared.The photocatalytic degradation of a certain concentration of methylene blue?MB?solution was used as a model to investigate the catalytic properties of the prepared magnetic titania nanospheres;the repeated use of the prepared magnetic titania nanosphere catalysts was explored.