Frabrication Of Three-Dimensional Graphene Sponge And Aerogel Materials And Investigation On Its Adsorption Property

In recent years,oil and organic liquid leakage accidents occur frequently,seriously polluting water resources,and directly threatening the health of marine organisms and human beings.Graphene(RGO)is used to prepare high performance adsorbents due to its hydrophobicity,large specific surface area and excellent chemical stability.However,how to effectively control the pore structure and surface hydrophobicity of graphene,maximize its excellent properties,achieve large adsorption capacity,fast adsorption rate and high selectivity remain to be explored in depth.In practical applications,graphene-based adsorbents will suffer from different temperatures,acid-base conditions and recycling performance.Based on this series of problems,this paper aims to synthesize two kinds of porous graphene adsorbents by template method and self-assembly method from the structure and properties of graphene,analyze their wettability,stability,adsorptive capacity and recyclability,and comprehensively explore the application of graphene materials in wastewater treatment.Specific research contents and results are as follows:1.By template method,RGO was loaded on the polyurethane sponge matrix to prepare graphene porous sponge by one-step extraction.Firstly,graphene was prepared by two methods:chemical reagent(hydrazine hydrate)reduction method and high temperature reduction method,respectively,named as CRGO and HRGO.By means of scanning electron microscopy(SEM),X-ray diffraction(XRD),Raman spectroscopy(Raman)and specific surface area tester(BET),it is proved that HRGO has more expansive lamellar structure,wider lamellar spacing,fewer surface defects and larger specific surface area than CRGO.Then RGO was loaded on PU sponge by one-step extraction method.The the water contact angle of HRGO/PU sponge was 150.0±2.5°and reached the superhydrophobic limit.RGO/PU sponge was modified with binary long and short chain organic silane solution,then the hydrophobicity was improved significantly.The water contact angle of modified S-HRGO/PU sponge reached 162.4±1.0°,which realized superhydrophobicity.S-HRGO/PU sponge exhibited high adsorption capacity for various organic solvents and oils,was 48-74 g/g,and maintained high adsorption stability after20 cycles.Moreover,this sponge held stable superhydrophobicity at different temperature and pH.For high viscous oil,the Joule-heat generated by electric current in sponge can reduce the viscosity.With the help of Joule-heat,the adsorption rate of S-HRGO/PU sponge for heavy oil was greatly increased,and the water/oil separation time was shortened by 37.9%.2.By self-assembly method,graphene aerogel were prepared.The plate-like graphene was assembled into three dimensional porous structure by Van der Waals'force and?-?bond.Three kinds of RGO aerogel were prepared by hydrazine reduction,vitamin C reduction and hydrothermal reduction,respectively.The influence of and reduced method and reaction time on the formation of RGO aerogel was studied,and the best technological conditions were explored.By comparison,it is found that RGO aerogel reduced by different methods has great differences in density,morphology,specific surface area and adsorption capacity.RGO aerogel was prepared by N-doped with RGO aerogel and adding fibrous material(biomass cellulose and carbon fiber)as support.It was found that N-doped carbon fiber/graphene aerogel improved the structural stability of aerogel,which exhibited ultra-light density(7.19 mg/cm~3)and high specific surface area(329.602 m~2/g).Meanwhile,its performance is further improved.N-doped carbon fiber/graphene aerogel had superhydrophobicity,high adsorption capacity(206.38 g/g),recyclability,excellent mechanical compression property and thermal stability.