▎ 摘　　要

NOVELTY - Preparing graphene oxide based on mixed acid system comprises e.g. washing graphite raw material using water, drying, smashing, passing through 200 meshes sieve, preparing graphite powder, adding the graphite powder in plugging agent, carrying out ultrasonic treatment, ultrasonic stirring, preparing the first acid system, preparing second acid system, adding first acid system into second acid system, preparing mixed liquid, ultrasonically stirring, preparing composite liquid, ultrasonically stirring, centrifuging, taking supernatant, adding ammonium sulfate solution, salting out and filtering. USE - The method is useful for preparing graphene oxide based on mixed acid system (claimed). ADVANTAGE - The method reduces the using amount of strong acid and decreases corrosion of equipment and heat generated by reaction, so that the reaction efficiency is higher, and is suitable for large-scale industrial production, uses simple equipment, prepares graphene with stable quality, is economical, and solves problem of producing large amount of heat, equipment corrosion during preparation, and low reaction rate. DETAILED DESCRIPTION - Preparing graphene oxide based on mixed acid system comprises (i) preparing graphite powder: washing the graphite raw material using water, drying, smashing, then passing through 200 meshes sieve, preparing graphite powder, where the graphite material is crystalline flake graphite piece, (ii) preparing first acid preparation system: adding the graphite powder in plugging agent and carrying out ultrasonic treatment, where the plugging agent is the first acid component, prepared graphite mass concentration is 0.1-1 g/ml of graphite-first acid component dispersing agent, the first acid component is organic strong acid and inorganic strong acid, using graphite-first acid component dispersant for ultrasonic stirring process for 0.5-3 hours, preparing the first acid system, (iii) preparing second acid system: smashing the oxidizing agent, then adding the second acid component and dissolving, where the dissolution temperature is 40-60 degrees C, the oxidizing agent mass concentration is 0.5-5 g/ml of oxidizing agent-second acid component solution, where the second acid component is organic weak acid and inorganic weak acid, adding longer chain organic acid in oxidizing agent-second acid component solution, where the mass ratio of graphite powder and longer chain organic acid is 100:0.1-1, carrying out ultrasonic treatment of longer chain organic acid oxidizing agent and second acid component solution for 0.5 hours, naturally cooling, preparing the second acid system solution, and (iv) preparing graphene oxide: at 40 degrees C low temperature, adding the first acid system according to 1-2 drops/second drop-wise speed in the second acid system, preparing mixed liquid, the adding volume of first acid system into the second acid system is calculated according to the following equation: C graphite V first acid system/C oxidizing agent V to be added second acid system = 1:2-8, where C graphite is graphite ? first acid component of graphite and dispersant mass concentration, V first acid system represents the volume of the first acid system, C oxidizing agent represents oxidizing agent-second acid component oxidant mass concentration, and V to be added second acid system represents the added volume of first acid system to the second acid system, ultrasonically stirring mixed liquid for 0.5-3 hours, at 70-100 degrees C ambient temperature, adding the mixture dropwise in water, placing for 3-10 minutes to prepare composite liquid, where the water volume is calculated according to the equation: C graphite V first acid system/ rho water V water = 1:20-50, where the C graphite is graphite-mass concentration of graphite in the first acid component dispersant, V first acid system represents the volume of the first acid system, rho water represents density of water, V water represents water volume, ultrasonically stirring composite liquid for 0.5-3 hours, then centrifuging for 5 minutes at a rotating speed of 4000 revolutions/minute, taking the supernatant, adding 2-5% ammonium sulfate solution in supernatant and salting out and filtering, using de-ionized water to clean filter cake, then washing, drying by alcohol, and preparing graphene oxide.