▎ 摘　　要

NOVELTY - Graphene oxide is prepared by adding natural graphite, potassium persulfate and phosphorus pentoxide into 180 mol/L concentrated sulfuric acid, heating solution in oil bath at 40-100 degrees C and reacting to obtain pre-oxidized graphite; adding pre-oxidized graphite and potassium permanganate in 180 mol/L concentrated sulfuric acid, reacting at 0-20 degrees C, then putting in oil bath at 20-60 degrees C and reacting for 0.5-5 hours to obtain yellowish brown muddy solution; adding 30 wt.% hydrogen peroxide to obtain bright yellow muddy solution; and filtering to obtain yellow graphene oxide. USE - Method for preparing graphene oxide (claimed). ADVANTAGE - The method is safe and convenient to operate, low in cost, and suitable for preparing and purifying graphene oxide in batch process; and utilizes easy to obtain raw material. The obtained graphene oxide is a single-layer structure, contains much active group and has excellent dispersivity in solvent. DETAILED DESCRIPTION - Preparation of graphene oxide comprises: (A) preparing potassium persulfate, phosphorus pentoxide, concentrated sulfuric acid and natural graphite at ratio of 1:0.2-5:0.2-7:0.2-6, adding natural graphite, potassium persulfate and phosphorus pentoxide into 180 mol/L concentrated sulfuric acid to obtain clear solution, heating solution in oil bath at 40-100 degrees C, reacting the solution for 1-7 hours to obtain black sediment mixture, cooling at 20-25 degrees C for 1-10 hours, then filtering, washing with secondary water until the filtrate is neutral, and drying the sediment in air to obtain pre-oxidized graphite; (B) preparing pre-oxidized graphite, potassium permanganate and concentrated sulfuric acid at ratio of 1:0.5-6:10-43, adding the pre-oxidized graphite and potassium permanganate in a reactor containing 180 mol/L concentrated sulfuric acid, reacting at 0-20 degrees C, then putting in oil bath at 20-60 degrees C and reacting for 0.5-5 hours to obtain yellowish brown muddy solution, adding 30 wt.% hydrogen peroxide to obtain bright yellow muddy solution, cooling to 20-25 degrees C, filtering, and washing with 5-20 wt.% hydrochloric acid to obtain yellow graphene oxide; and (C) purifying graphene oxide by preparing sulfuric acid and hydrogen peroxide mixed aqueous solution and placing the yellow graphene oxide in the mixed aqueous solution, vibrating, dispersing, and filtering to obtain yellow cake-like material.