Preparation And Applications Of Magnetic Nano Carbon-polymer Composites

One-dimension-linear multiwalled carbon nanotubes (MWCNTs) and two-dimension-planar graphene are two kinds of very important carbon materials in recent years, which arewidely used for adsorption of organic substance and dye in water. However, due to itsdifficult to disperse in water, and once it is dispersed in water can be difficult to separateagain, moreover its surface functional groups is limited, which limits the application inwastewater treatment. Herein, this thesis prepared grapheme oxide (GO) by a modifiedHummers method, and then the preparation of the Magnetic Fe3O4-GO composite materialswere prepared by chemical co-precipitation.Then by treating polyethylene glycol (PEG),ethylenediamine for the composite material, the magnetic Fe3O4-GO-PEG compositematerials and aminated magnetic Fe3O4-GO composite material was prepared. In addition, bydoping carboxyl MWCNTs into Fe3O4-GO composite material, the magneticFe3O4-(GO+MWCNTs)-PEG composite material was prepared. Finally, the three kinds ofcomposite material were applied to adsorption and separation of phenol, methylene blue inwater.1. The single-layer GO which contained a lot of oxygen-containing groups (hydroxylcarbonyl epoxy group) was prepared by a modified Hummers method. SEM and XRD resultsindicated that the layers of GO have been separated and the layers spacing was0.859nm; TheN2adsorption-desorption isotherms of GO showed that the surface area of GO was326.6m2/gwith a large number of adsorption sites.2. Magnetic Fe3O4-GO composite material is prepared by chemical coprecipitation atconstant temperature water bath of80℃, and the best quality ratio of Fe3O4and GO equal to4:1obtain by the infrared (FT-IR) and XRD analysis. Magnetic Fe3O4-GO-PEG was thensynthesis through chemical grafting method on the basis of Fe3O4-GO. FT-IR and TGA testsindicated that the PEG had been grafted to the magnetic Fe3O4-GO, transmission electronmicroscopy (TEM) results showed that the addition of PEG significantly improved thedispersion of Fe3O4on GO. The composite material was applied to the adsorption andseparation of methylene blue in water, test results show that the best adsorption effect wasobtained at the molecular weight of PEG is800, and the maximum adsorption capacity was 97.09mg·g-1.3. Aminated magnetic Fe3O4-GO composite material was prepared through aminationprocess of Fe3O4-GO with ethylenediamine. FT-IR and TGA results showed that magneticFe3O4-GO had been successfully grafted by ethylenediamine. SEM results showed that thegrafting of ethylenediamine improved the dispersion of Fe3O4. The composite materials wasapplied to the adsorption and separation of organic pollutants of phenol in water, it was foundthat the adsorption process followed pseudo two order kinetics model and the adsorptionisotherms were fitted to Langmuir model, the maximum adsorption capacity was48.24mg·g-1.4. GO+MWCNTs hybrid was Prepared by chemical grafting method, thenFe3O4-(GO+MWCNTs)-PEG was synthesis on the basis of Fe3O4-GO. FT-IR, XRD and SEMtests showed that GO and MWCNTs has been combined together effectively, the addition ofMWCNTs broadened the interlayer spacing of GO, and Fe3O4has been coordinated into theGO+MWCNTs hybrid successfully. FT-IR and TGA tests indicated that the PEG had beengrafted to the magnetic Fe3O4-(GO+MWCNTs), the corresponding amount of which is about10%. The composite materials was applied to adsorption and separation of methylene blue inwater, test results showed that best adsorption effect was obtained at the doping content ofMWCNTs was40%, the maximum adsorption capacity was119.7mg·g-1.