Preparation Of Functionalized Graphene Composite And Its Application In Removal Of Dye Pollutants

Graphene is a flat monolayer of carbon atoms densely packed into atwo-dimensional honeycomb lattice. As a new carbon nanomaterial appeared afterfullerenes and nanotubes, graphene is a basic building block for graphite materials ofall other dimensionalities. Since it was first prepared by the mechanical exfoliation ofgraphite in2004, graphene has aroused great attention on the horizon of nanomaterialscience due to its unique mechanical, electrical, optical and thermal properties.Although graphene has great potential applications in the field of storage materials,catalysts, sensors and biomedical, it is easy to agglomerate through van der Waalsinteraction, which results its poor dispersibility in solvents. Chemicalfunctionalization of graphene can not only overcome these above obstacles, but alsohas important academic research value in expanding the applications of graphene.This article focus on the surface modification of graphene to prepare two differentkinds of graphene based composites. It can be summarized as follows.1）Few-layers graphene was prepared by the microwave assisted exfoliation andreduction of graphite oxide in Ruoff’s report. Using the as-obtained graphene as rawmaterial, we synthesized ethylenediamine functionalized graphene (EDA–G) by thenucleophilic addition of lithium ethylenediamin derivative. The presence ofethylenediamine (EDA) chain in graphene was identified by Fourier transforminfrared spectroscopy (FTIR), electronic energy loss spectroscopy (EELS), X-rayphotoelectron spectroscopy (XPS),Raman spectrum and Zeta potential. The resultshowed that EDA was homogeneously distributed on the whole surface of theobtained EDA–G and the density of the EDA was3.1mmol g-1, which was muchhigher than other reports. Using the resulting EDA–G as a precursor, we also preparedgraphene based supramolecular hydrogels with chemically-responsive property. Whenadding a competitive host–CD or competitive guest AdCNa, the graphene hydrogelsexhibited the gel to sol transition.2）β–Cyclodextrin functionalized graphene oxide（GO–β–CD） was preparedunder alkalin condition using graphene oxide obtained by Hummers method as rawmaterial. FTIR、13C NMR and Raman spectrum confirmed that β–Cyclodextrin (β–CD)was successfully bonded to the surface of graphene oxide. TGA showed that the amount of β-CD in GO–β-CD is36.5mg g-1. What’s more, we also studied theadsorption characteristic in the removal of fuchsin acid from solution. The resultsshowed that β-CD grafted graphene oxide could efficiently remove fuchsin acid dyefrom the water at a high speed and this material can be easily recycled and reusedwith little loss of adsorption capacity after four consecutive cycles of reuse.