Preparation Of Fe₃O₄ Nanowire@GO Hybrid And Its Electromagnetic Shielding And Adsorption Properties

Graphene oxide has potential applications in hydrogen storage composites,electromagnetic shielding,and environmental water pollution treatment due to its large specific surface area,high electrical conductivity,and thinnest and lightest properties.However,with the development of new technologies,the requirements for materials are getting higher and higher,and the functional modification of graphene oxide has become a hot research topic.In this·paper,the Fe3O4 nanowire@graphene oxide(Fe3O4 NWs-pDA@GO)was prepared by one-step method based on the principle of coprecipitation.The growth mechanism of Fe3O4 nanowires was investigated.The orientation state and composite materials of Fe3O4.NWs-pDA@GO were systematically studied.The relationship between the orientation state of Fe3O4 NWs-pDA@GO and the oxygen barrier properties and electromagnetic shielding properties of composites was also studied.On the other hand,Fe3O4 NWs-pDA@GO-PEI was prepared by using polyetherimide(PEI)as modifier.And the adsorption properties of Fe3O4 NWs-pDA@GO-PEI for methylene blue(MB)and heavy metals(Cu2+)were further discussed.The specific work is as follows(1)Fe3O4 nanowire@graphene oxide(Fe3O4 NWs-pDA@GO)was prepared by one-step method based on the principle of coprecipitation,and the orientation state of Fe3O4 NWs-pDA@GO and the oxygen barrier properties and electromagnetic shielding properties of the composite were systematically studied.The characterization methods of Infrared Spectroscopy(FTIR),Thermogravimetric Analysis(TGA)and Raman spectra showed that dopamine can form different complexes with Fe3+/Fe2+in different pH solution environments,and finally lead to the formation of Fe3O4 nanowires.At the same time,the formed polydopamine utilizes its own adhesion to make Fe3O4 nanowires stably bind to the surface of graphite oxide.Further,the weak magnetic field induced Fe3O4 NWs-pDA@GO orientation in the resin matrix,Fe3O4 NWs-pDA@GO/EP with different orientation degrees were prepared,and the oxygen barrier test showed that when the external magnetic field reached 35 mT,Fe3O4 NWs-pDA@GO has an orientation of 96%in epoxy resin and a minimum oxygen permeability coefficient of 3.84 cm3/m2·24 h·0.1 MPa,which is a decrease of 36.7%compared to pure EP.The electromagnetic shielding test showed that the composite material with 2 wt.%Fe3O4 NWs-pDA@GO oriented in a magnetic field of 35 mT showed obvious anisotropy in electromagnetic shielding performance.The electromagnetic loss perpendicular to the incident wave direction is significantly larger than that of the randomly distributed composite material,and the composite material oriented parallel to the incident wave direction is significantly smaller than the randomly distributed composite material.(2)Fe3O4 NWs-pDA@GO-PEI was prepared by using polyetherimide(PEI)as modifier,and the adsorption properties of Fe3O4 NWs-pDA@GO-PEI for methylene blue(MB)and heavy metals(Cu2+)were further discussed.The characterization methods such as UV-Vis and inductively coupled plasma mass spectrometry(ICP-MS)showed that Fe3O4 NWs-pDA@GO-PEI had higher adsorption effect for organic dye(MB)and heavy metal ions(Cu2+).The adsorption capacity and the optimal adsorption capacity reached 112.3 mg/L and 63.54 mg/g,respectively.And its adsorption kinetics and adsorption thermodynamics are consistent with the quasi-secondary kinetic model and the Langmuir adsorption theory.After five cycles of use,its adsorption capacity could be maintained above 80%.