| Expandable graphite is an efficient functional carbon-based material,which can expand at a high temperature or microwave irradiation to produce expanded graphite with a high expansion volume.Expanded graphite can be widely used in sealing,flame retardant,oil spill adsorption,catalysis and other industrial fields.However,the traditional chemical oxidation preparation method of expandable graphite generally uses strong acids and oxidants such as concentrated sulfuric acid,high orange acid and potassium as intercalation agent and oxidant,which will produce severe environmental pollution with poor safety performance and is seriously hazardous to health.Thus,its application is limited in industrial production.Therefore,the innovation of expandable graphite intercalation process,as well as expandable graphite preparation technology,and the realization of its green preparation are great of importance to promote its industrial application;also it is the urgent in the field of graphene carbon material industry.The strategy proposed in this thesis focuses on revolutionizing the intercalation process of flake graphite and realizing its electrochemical efficient intercalation.We designed an electrochemical intercalation device for the production of expandable graphite,and determined the optimal process conditions for the electrochemical intercalation of expandable graphite through single-factor and orthogonal experiments,aiming to explore the green preparation of expandable graphite with the help of microwave expansion technology.Subsequently,the morphologies,histomorphologies and chemical compositions of the fabricated samples were characterized and monitored.In this thesis,for the application of expanded graphite,the tribological property of shackled phosphorus/expanded graphite/polyester resin/polytetrafluoroethylene（PTFE）composite-based material produced using expanded graphite as reinforced additive was tested.The adsorption performances of nepheline organics and oil substances by expanded graphite,as well as that for the uptake of volatile organic compounds were also evaluated.The friction coefficient of fabricated PTFE-based composite is 0.112 and the wear rate was 6.31×10-15m3/Nm,which shows that this composite has an excellent friction and wear reduction performance.The optimal preparation process conditions for preparing expandable graphite by electrochemical oxidation are that:natural flake graphite（g）:glacial acetic acid（m L）:deionized water（m L）:sodium nitrate（g）=5 g:75 m L:125 m L:6.5 g for the addition ratios of reacts,natural flake graphite and red copper mesh employed as anode and cathode,60 min for the react time,and70 m A·cm-2 for the current density.After the series of treatments involving water washing,filtration and drying,the expandable graphite（GIC）was prepared.GIC can be expanded by microwave irradiation to produce expanded graphite（EG）;the tested expanded volume（EV）of this sample is 332 m L/g.In comparison with activated carbon,the expanded graphite was less effective in capturing nephews,but its performance for the uptake of oil was higher.The expanded graphite can be reused after desorption treatment,so the expanded graphite has an excellent reuse performance,which indicates that the expanded graphite can be used for the emergency disposal of environmental oil spills.The application of expanded graphite is also investigated in this thesis for the adsorption and disposal of volatile organic compounds（VOCs）and the reclamation of the adsorption spent.The adsorption device with the expanded graphite used as adsorbent to adsorb VOCs was constructed by simulating the working conditions of an auto parts paint booth,and saturated expanded graphite was regenerated by microwave expansion.After ten cycles,results of SEM,Raman and AFM measurements attested that graphene nanosheets are successfully produced from the spent expanded graphite.The strategy for the reutilization of spent expended graphite is achieved,exhibiting a promising prospect in the practical application. |
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