Preparation And Performance Study Of Graphene Oxide/silica Hybrid Nanofiltration Composite Membrane

Graphene has attracted the attention of the scientific community since its discovery.Graphene is a two-dimensional nanomaterial with only one atom thickness.The unique structure of graphene gives graphene various properties.Its excellent properties in mechanical,optical,electrical,and thermal aspects have been widely studied and explored by scientists.Graphene has also been proved to have great potential in physics,chemistry,biology,materials and other aspects.After theoretical verification and practical research,graphene and its derivatives can be applied to water treatment fields such as wastewater treatment and seawater desalination treatment,with a certain development potential.The purpose of our research is to alleviate the shortage of fresh water resources and expand the application of graphene and its derivatives in the field of water treatment.In this paper,the following research was carried out on graphene oxide composite materials and composite membranes:The graphene oxide?GO?used in this article was successfully prepared by using the modified Hummers method.After the successful preparation of graphene oxide,we prepared graphene by multi-reduction method.We characterized the prepared graphene oxide and graphene by Ultraviolet and visible spectrophotometry?UV-Vis?,transmission electron microscope?TEM?,X-ray diffraction?XRD?,Fourier transform infrared spectroscopy?FTIR?.After research and discussion,graphene oxide is lamellar,thin and transparent,with wrinkles on the surface.A large number of oxygen-containing functional groups exist on the surface of graphene oxide sheets,including carboxyl groups,hydroxyl groups,and epoxy groups.At the same time,graphene oxide has good hydrophilic properties and can form a stable dispersion in water.After the graphene oxide is prepared,it is compounded with other materials on this basis.Through in situ hydrolysis,using tetraethylorthosilicate?TEOS?as the silicon source,the graphene oxide/silica?GO/SiO₂?hybrid composite was successfully prepared in an alkaline environment.Through various characterization methods,the graphene oxide/silica composite was characterized,analyzed and discussed.Transmission electron microscopy images can clearly observe the dense silica particles loaded on the graphene oxide surface.Fourier transform infrared spectroscopy?FTIR?,X-ray photoelectron spectroscopy?XPS?and Raman spectroscopy all indicate that silica is successfully loaded on the surface of graphene oxide sheets.The BET specific surface area test?BET?image shows that the graphene oxide/silica composite material is a porous material.At the same time,the thermal stability of graphene oxide/silica is further improved than pure graphene oxide.On the basis of graphene oxide/silica composite materials and graphene oxide,we successfully prepared graphene oxide/silica composite membranes and pure graphene oxide membranes by vacuum suction filtration.The morphology of the membrane surface and membrane cross-section of the graphene oxide/silica composite membrane was observed by field emission scanning electron microscope?FESEM?.Atomic force microscopy?AFM?results indicate that the graphene oxide/silica composite membrane indicates increased roughness.The graphene oxide/silica composite membrane has a water contact angle of less than ninety degrees and has hydrophilic properties.In order to study the application of graphene oxide/silica composite membrane in the field of water treatment,we conducted a water flux test and a rejection test on the composite membrane.The pure water permeability of graphene oxide/silica composite membrane and pure graphene oxide membrane gradually decreases with the increase of membrane thickness,but the water flux of GO/SiO₂ composite membrane is higher than that of pure GO membrane Be bigger.The rejection rate of rhodamine B?Rhb?by GO/SiO₂ composite membrane showed a positive correlation with the membrane thickness,and the rejection rates were all greater than 98%.Graphene oxide/silica composite membrane has certain development potential in the field of water treatment.