▎ 摘　　要

NOVELTY - Preparing graphene oxide comprises carrying out oxidation reaction of graphite in concentrated acid and strong oxidizing agent to obtain graphite oxide containing reaction mixture, diluting the reaction mixture using water to obtain an aqueous dispersion, stirring the aqueous dispersion, allowing to stand for separation and removing the supernatant, diluting the resulting residue with water into an aqueous dispersion, grading and filtering, drying the fine sieve material, pulverizing, carrying out thermal expansion, dispersing, ultrasonic processing, and drying. USE - The method is useful for preparing graphene oxide (claimed). ADVANTAGE - The method shortens the preparation of graphene oxide and produces high purity graphene oxide. DETAILED DESCRIPTION - Preparing graphene oxide comprises (i) carrying out oxidation reaction of graphite in concentrated acid and strong oxidizing agent to obtain graphite oxide containing reaction mixture, (ii) diluting the reaction mixture using water to obtain an aqueous dispersion, where the insoluble solid content is 0.1-15 g/l of an aqueous dispersion, (iii) stirring the aqueous dispersion, allowing to stand for separation and removing the supernatant, (vi) repeating step (ii) and (iii) for 1-3 times, (iv) diluting the resulting residue with water into an aqueous dispersion, where the insoluble solid content is 0.1-15 g/l of the aqueous dispersion, grading and filtering the resultant aqueous dispersion as follows: filtering the resulting aqueous dispersion through 30-200 crude sieve, processing the crude sieve with flushing action of the water or diluting with water to form the aqueous dispersion, where the insoluble solid content is 0.1-15 g/l of the aqueous dispersion, filtering the aqueous dispersion through 200-300 fine sieve, where the crude screen mesh is larger than the fine screen mesh, filtering by the first grade crude sieve and repeating for 1-3 times; (v) drying the fine sieve material and pulverizing to obtain a crushed material; (vi) carrying out thermal expansion of crushed material in an inert atmosphere for 30-120 minutes at 300-400 degrees C, (vii) washing the thermal expansion product with water and drying to obtain dried product, (viii) dispersing the dried product in water to form an aqueous dispersion, ultrasonic processing, microwave processing and/or high shear processing the resulting aqueous dispersion to obtain graphene oxide sol, and (ix) drying the resulting graphene oxide sol to obtain graphene oxide. An INDEPENDENT CLAIM is also included for preparing the graphene, comprising (a) preparing the graphene oxide according to above method, and (b) reducing the graphene oxide to obtain graphene.