Research On The Mechanism And Influencing Factors Of Graphite Oxide’s Percolation Transformation

As an important intermediate product of graphene,a new material,graphite oxide has received extensive attention for its purification and functionalization technology.The most common preparation method of graphite oxide is the Hummers method.The product contains a variety of impurities.During the process of separating and purifying the graphite oxide solution,the graphite oxide solution undergoes percolation and forms a stable colloid with water,causing separation and purification difficulties.In view of this problem,this paper mainly studies the characterization method of percolation transition threshold of graphite oxide solution and the mechanism and synergistic effect of alkali metal on percolation transition threshold of graphite oxide slurry.Based on the classic percolation theory and DLVO colloidal stability theory,by adding different kinds of metal ions to pure graphite oxide aqueous solutions of different concentrations,the solution conductivity,thermal conductivity,viscosity,surface tension and absorbance change with the concentration of metal ions Curve.XRD,SEM,TEM,and Zeta characterization methods were used to analyze the state of graphite oxide solution in the abrupt interval of conductivity,thermal conductivity,viscosity,surface tension,and absorbance,and to confirm whether the percolation transition occurred.Then compare the second-order rate of change of the electrical conductivity,thermal conductivity,viscosity,surface tension and absorbance of the graphite oxide solution,screen the indicators that can significantly indicate the percolation transformation process of the graphite oxide solution,and explore its Universality under different concentrations of graphite oxide and different metal ions type conditions.The results show that the electrical conductivity is the most significant physical parameter to characterize the percolation transition threshold of the graphite oxide solution.The slope of the curve of the change in concentration at the percolation threshold is 645.31%.Even if the solid concentration of the graphite oxide solution or the valence of the ion species is changed,the conductivity is still applicable.The process of washing and purifying the graphite oxide raw material solution and the process of adding metal ions to the pure graphite oxide solution are reversible,and the mechanism of percolation transformation that occurs in both cases is the same.In order to solve the problem of separation of graphite oxide due to percolation transition,the conductivity was used as the characterization method of percolation transition threshold,the valence state of the metal ion in the purification agent,the p H of the solution and the ambient temperature were changed.Factors and mechanism of percolation transition threshold of graphite slurry,analyze their synergy and find out the best operating conditions.The greatest degree of influence on the percolation transition threshold of graphite oxide is the type and valence of metal ions,followed by the p H of the solution,and the smallest degree of environmental temperature.The type and valence of metal ions interact with the p H value of the solution.The optimal filtration conditions are trivalent metal purifying agent,p H = 4.92,and 35 °C.The results of this paper provide some guidance for the further purification and separation of graphite oxide and its functional modification,and have certain reference value for the industrialized large-scale,high-purity preparation of graphite oxide.The main work studied in this paper was supported by the National Natural Science Foundation of China,“The Influence Mechanism of Self-assembly and Percolation in the Filtration Process of Microscale Graphite Oxide Layered Materials”.Thanks again to the National Funding Committee for its support for the work of this project.