Study On Assembly Of Dual Network Graphene Aerogel And Oil/Water Separation Performance

Adsorptive materials play a vital role in the later stage of marine oil spill accident treatment—the removal of oil film.Conventional adsorption materials such as oil-absorbing tampons,oil-absorbing resins and carbon particles have the disadvantages of low adsorption capacity(less than 50 g·g^-1),poor oil-water selectivity,difficult oil recovery and so on.Graphene aerogels are potential adsorption materials due to their developed pore structure and inherent hydrophobicity.However,at present,graphene aerogels are often doped with cellulose and carbon nanotubes to improve their performance,which is complicated and expensive.How to improve the mechanical and adsorption properties of the material only by adjusting its internal structure is an urgent problem to be solved.Aiming at the above problems,this paper adopts the reducing agent and crosslinking agent to control the internal structure of graphene aerogels collaboratively.A physical stacking and chemical crosslinking dual network graphene aerogel was prepared,which processes the advantages of simple process,high adsorption,oil-water high selectivity,compressible and great repeated use.It is of great practical significance for efficient removal and recovery of marine oil.In this paper,a dual network graphene aerogel preparation method was developed.The improved Hummers method was used to prepare graphene oxide.Through single factor investigation,the preparation conditions of dual network graphene aerogel were optimized,and its surface chemistry,microstructure,wettability,specific surface area,compressibility and flame retardancy were comprehensively analyzed.The adsorption capacity was evaluated by adsorption capacity and adsorption kinetics experiments.The separation characteristics of oil and water were investigated by adsorption-analytical cycle and simulated adsorption-recovery experiment of marine oil spill.Based on the superhydrophobic/superhydrophilic surface construction mechanism,the formation of rough nano-micro protrudes on the surface and excellent hydrophobicity are proved.Through the internal structure characterization analysis the generation principle of the physical stacking and chemical crosslinking of the dual network.The hydrophobic force on the surface of the material was quantitatively analyzed by means of chemical force probe technique.The results showed that the the optimum preparation method of double network graphene aerogels is ultrasonic for 45 min with 200 W,centrifugation at 1000 rpm for 5 min,with the concentration of graphene oxide,ascorbic acid and cysteamine are 4 mg·m L^-1,4 mg·m L^-1,0.25mg·m L^-1,respectively.Surface chemical analysis and microstructure results confirmed that internal structure of graphene aerogel was cooperatively regulated by reducing agents and cross-linking agents,which made the structure transit from ordered layered stack structure to criss-crossing dual network structure.Comparing with the traditional hydrothermal reduction graphene aerogels,the dual network graphene aerogel processed ower density(4.2 mg·cm^-3),a larger specific surface area(366.8 cm²·g^-1),excellent mechanical properties and a high adsorption capacity(150-310 g·g^-1)for a variety of oils and organic solvents.After five adsorption extrusion cycles,the recovery of oil was as high as 85%.and the separation efficiency was 99.9%,which is able to meet the offshore oil efficient adsorption and recovery.Through the oil absorption-separation simulation device,the efficiency of oil-water separation was up to 99.5%.Based on the supe-hydrophobic/superlipophilic surface construction mechanism,the rough microstructure and low-oxygen content make it exhibit excellent hydrophilic performance.The dual network structure of physical stacking and chemical crosslinking enhanced the skeleton structure,regulated the pore structure size,and realized the high adsorption and compressibility of the material.Nanomechanical methods revealed the strong hydrophobicity on the surface of the dual network graphene aerogel,which enabled it to achieve efficient oil-water separation.