Preparation And Application Study Of Ionic Liquid Functionalized Magnetic Graphene-based Nanocomposites

Magnetic nanoparticles(NPs) have been used in various fields, such as automatic control, information storage, biological medicine and wastewater treatment, because of their unique structure and excellent magnetic properties. Magnetic nanocomposites have a broad application prospects especially in wastewater treatment with its excellent properties, which is formed by combining magnetic nanoparticles(NPs) and other precursors through physical or chemical method. In this paper, Fe3O4 NPs and magnetic graphene-based nanocomposites have been designed and prepared for wastewater treatment. The main contents and results are as follows:Firstly, magnetic ionic liquid([BMIm]FeCl4) was used as magnetic resource to prepare Fe3O4 NPs by a simple chemical co-precipitation method. The as-formed Fe3O4 NPs with a diameter as small as 5-7 nm, X-ray diffraction(XRD) spectra analysis showed that the characteristic diffraction peaks of Fe3O4 NPs is relatively sharp and with good crystalline. The Fe3O4 NPs have a good ferromagnetic by this synthetic method, which is a huge potential material in application area of magnetic composites.Secondly, graphite oxide(GO) was prepared according to a modified Hummers method, [BMIm]Fe Cl4 and GO combined under the effect of π-π interaction, Fe3O4 NPs appeared in the surface of GO through chemical co-precipitation method.Magnetic nanocomposites with different proportion of GO and Fe3O4 NPs were prepared by controlling the adding amount of reactant. SEM and TEM images show that the as-formed Fe3O4 NPs with small size were uniformly deposited on GO sheets,which indicated the existence of GO plays a inhibitory effect for the reunion of Fe3O4 NPs. The research results indicated that the content of GO is 19.3 wt% of the composite samples with the best property. The adsorption effect of GO@Fe3O4nanocomposites for methylene blue is significantly enhanced, the adsorption equilibrium can be quickly reached, and showed good magnetic responsiveness under the action of magnetic field.Thirdly, the experiment was designed and improved, the GN@Fe3O4nanocomposites was prepared through a simple method by adding ammonia in the presence of GO and Fe2+ to control the pH of the reaction. Fe3O4 NPs with a diameter10-20 nm were deposited on GN sheets. Large specific surface area of GN has verygood adsorption effect to methylene blue, and adsorption capacity can reach 45.2mg/g with good magnetic responsiveness.At last, GO was prepared according to a modified Hummers method, then reduced to GN by NaHB4. GN was dissolved in [BMIm]Cl containing [BMIm]Fe Cl4 to form a homogeneous solution after ultrasonic treatment to prepare GN@Fe3O4nanocomposites through chemical co-precipitation method. Fe3O4 NPs with small size coated on the GN surface and effectively filled in the layers of GN. The magnetic nanocomposites showed excellent adsorption performance for methylene blue with small particle size of Fe3O4 NPs and large specific surface area of GN.