Preparation Of Functionalized Graphene-based Composite Bulk Materials And Study On Oil Adsorption Performance

In this thesis,based on the oil diffusion data obtained by C++programming,graphene was used as the basic material to realize the performance optimization and regulation of graphene aerogel through the functionalization of nanoparticles to achieve large oil absorption capacity,high oil-water separation selectivity and efficient recycle performance.The optimization and the functionalization mechanism are applied to the preparation of high-efficiency PU sponge,and the prepared functionalized graphene-based bulk material is used for oil-water separation.The specific research contents are as follows:First,based on the threshold division,the oil diffusion-processing photo is processed to obtain the oil diffusion surface area and the oil layer thickness at different time and different wind level conditions by C++programming.The results show that as the wind level increases,the time for the oil to spread to a stable state becomes significantly shorter.The diffusion area of 100?L diesel,lubricating oil and crude oil are distributed in the range of 3000-8000 cm²,and the oil layer thickness is distributed in the range of 100-300 nm.Because of its low viscosity,n-hexane quickly covered the limited water surface under the action of water surface tension,which reduced the surface tension between water and air.Then the diffusion of n-hexane to the surface of n-hexane molecular layer occurred,and the driving force changed greatly,so the n-hexane has the smallest diffusion surface.The diffusion area of 500?L dyed n-hexane was 560cm² and the diffusion oil layer thickness was 9?m.Based on the diffusion data,the diffusion areas of 1 ton of lubricating oil,diesel oil,crude oil and dyed n-hexane are predicted to be 5.46km²?4.86 km²?11.38 km² and 0.18 km²,respectively,which reveals the rapid spread of oil under natural conditions and the necessity of emergency treatment with high-efficiency oil-absorbing materials.Secondly,the porous magnetic Fe₃O₄ nanoparticles are ultrasonically mixed uniformly with the graphite oxide(GO)aqueous solution,and the functionalized graphene aerogel was obtained by hydrothermal self-assembly,freeze-drying,microwave irradiation and PS microsphere surface modification with ethylenediamine as reducing agent.The results show that Fe₃O₄ nanospheres and PS microspheres are embedded in the graphene aerogel skeleton,respectively,and form a typical micro-nano hierarchical rough structure,and synergistically with the PS surface hydrophobic modification,which makes aerogel with WCA exceeding 140^o.The anchoring of Fe₃O₄ nanoparticles on the graphene sheets reduces the space for the graphene sheets to aggregate during the reduction process,effectively improving the stability and compression resistance of the three-dimensional network skeleton structure.The graphene aerogel porosity reaches 99.7%and the adsorption capacity of lubricating oil and crude oil are37 and 40 times of its own mass respectively.The embedding of Fe₃O₄ nanoparticles gives the graphene aerogel good magnetic responsiveness,and after the saturated oil absorption,the aerogel can be recycled by magnetic recovery-mechanical extrusion.Third,the graphite oxide aqueous solution was mixed with(3-mercaptopropyl)trimethoxysilane(MPS)/hydrochloric acid solution,and the graphene aerogel was fabricated by self-assembly and natural drying with MPS as a reducing agent and a functionalizing agent.The results show that the silicon thiol formed during the hydrolysis of MPS can effectively reduce the graphite oxide to graphene in the hydrothermal self-assembly process,and the different scale polysiloxane nanoparticles formed by the uneven hydrolysis of high concentration MPS are distributed on the surface of the graphene skeleton.The graphene aerogel skeleton endows with a macroporous structure of 1-5?m and a mesoporous structure with a size of less than 50 nm.The hydrophobic surface of polysiloxane and the hierarchical rough surface constructed by polysiloxane at different scales synergistically promoted WCA over 160^o.The graphene aerogels have no thermal weight loss at 250 ^oC,due to the good dispersion of graphene sheets and the chemical bonding force between graphene sheets and polymer within the aerogels.Based on the action mechanism of MPS multi-functionalization,the graphene aerogels with adjustable properties were obtained by hydrothermal self-assembly and freeze-drying process with the regulation of MPS concentration in graphite oxide aqueous solution.The results show that when the concentration of MPS increased from 0.01 vol%to 0.2 vol%,the aerogel pore size increased from less than 30?m to 300?m,and the size of polysiloxane nanoparticles on the graphene sheets increased significantly and changed from spherical to petal-like.The high concentration of MPS not only increases the spacing of the graphene sheets and the effectiveness of GO reduction,but also ensures that the GAs density can be tuned from3.5 to 64 mg·cm^-3,and the wettability can be controlled from hydrophilic to highly hydrophobic.The aerogel with a density of 3.5 mg·cm^-3 adsorbed 182 and 143 times of lubricating oil and n-hexane of its own weight,respectively,and maintained high adsorption capacity in 20 cycles.Finally,based on the mechanism of reaction for MPS and GO,functionalized graphene/polyurethane(FGN/PU)sponge was solvothermally synthesized by a one-pot method using the PU sponge as a skeleton.The results show that during the solvothermal reaction,the silicon thiol formed by the hydrolysis of MPS can not only dehydrate and condense with the hydroxyl group on the surface of PU sponge,but also the hydroxyl group at the other end of the silicon thiol can dehydrate and condense with the hydroxyl group on the surface of GO.Then the crater-like graphene sheet layer is closely adhered to the surface of the PU sponge skeleton,thereby effectively improving the mechanical strength and corrosion resistance of the sponge skeleton.The excellent hydrophobicity of the polysiloxane and the rough structure formed on the surface of the sponge skeleton synergistically contribute to the functionalized sponge with WCA over 160^o.Modified sponge can be used as an efficient filter,which can be connected with a vacuum system to continuously and selectively separate oil from water.Because the functionalized PU sponge retained original PU structural integrity,at the same time,the material was superhydrophobic and highly structurally stable,and capable of separating oil up to 53,000times of its own mass with high oil–water separation efficiency(>99.5%).