▎ 摘　　要

NOVELTY - The preparation method of graphene oxide involves adding crystalline flake graphite into a beaker, adding phosphoric acid, stirring, leaving still, and naturally cooling, adding sulfuric acid to the moderate acidification system, stirring, cooling, dripping potassium permanganate to the acidification system, reacting in water bath, heat-preserving, cooling, pouring into crushed ice, dripping hydrogen peroxide, centrifugally separating the obtained mixture, washing the lower layer precipitate, centrifugally separating or filtering, and vacuum drying. USE - Preparation method of graphene oxide (claimed). ADVANTAGE - The method enables preparation of graphene oxide with wide raw material source, excellent oxidization effect, uniform product size, high yield, excellent energy saving effect, emission reduction effect, excellent safety, and stability without spark, by simple, economical and industrial process. DETAILED DESCRIPTION - The preparation method of graphene oxide involves (1) adding crystalline flake graphite into a beaker, adding 85 %mass phosphoric acid, stirring at room temperature for certain time, leaving still for overnight, and naturally cooling to room temperature, (2) adding 95 %mass sulfuric acid to the moderate acidification system in step (1), stirring at room pressure for certain time, placing in a cold water groove, and cooling to room temperature, (3) dripping potassium permanganate to the acidification system in step (2), reacting in water bath at 45-55 degrees C, heat-preserving for a certain time, cooling to room temperature, pouring into crushed ice, dripping 30 %mass hydrogen peroxide under condition of stirring till the reaction liquid fades, (4) centrifugally separating the mixture obtained in step (3), washing the lower layer precipitate with deionized water, 30 %mass hydrochloric acid, and anhydrous ethanol two times, centrifugally separating or filtering by a microporous filter film, and vacuum drying.