▎ 摘　　要

NOVELTY - Pollution-free low cost preparation of graphene oxide comprises mixing graphite and strong acid, adding strong oxidizing agent, continuously stirring, oxidizing to obtain exfoliated graphite sheet, centrifugally separating the supernatant i.e. strong acid, which is used for the next reaction, slowly pouring the mud product in deionized water, diluting, stirring, repeatedly washing the centrifuge with hydrochloric acid diluted in deionized water, centrifuging to separate single layer graphene oxide aqueous solution and concentrating the graphene oxide aqueous solution. USE - Pollution-free low cost preparation of graphene oxide. ADVANTAGE - The pollution-free low cost preparation method provides high density graphene oxide with high specific surface area. It is safe and controllable, has low energy consumption and no explosion danger, circularly uses the concentrated sulfuric acid, provides waste material, which can be used into fertilizer, and fully uses the raw materials. DETAILED DESCRIPTION - Pollution-free low cost preparation of graphene oxide comprises mixing graphite and strong acid by stirring at 0-40 degrees C for 5-30 minutes, adding strong oxidizing agent, continuously stirring for 1-8 hours, oxidizing to obtain exfoliated graphite sheet, centrifugally separating the supernatant i.e. strong acid, which is used for the next reaction, slowly pouring the mud product in deionized water, diluting, stirring, repeatedly washing the centrifuge with 1 mol/L hydrochloric acid diluted in deionized water, centrifuging to separate single layer graphene oxide aqueous solution, adjusting the pH of wastewater at 7 using ammonia, where wastewater contains nitrogen, potassium and iron elements of inorganic fertilizer, concentrating the graphene oxide aqueous solution by spray drying or supercritical drying and obtaining high density graphene oxide powder with high specific surface area.