▎ 摘　　要

NOVELTY - Preparing a graphene magnetic aerogel involves: (1) pre-oxidizing graphite by separately taking graphite powder, concentrated nitric acid, concentrated sulfuric acid and potassium permanganate, adding to a reaction vessel, stirring and mixing to get a dark brown viscous liquid, washing the viscous liquid to pH of 6.8-7.2 and drying, then putting the dried material into a crucible with a temperature of 800-1000 degrees C, covering the crucible with a lid, cooling the crucible to room temperature to obtain an expanded graphite, then taking the expanded graphite, potassium persulfate and phosphorous pentoxide, heat preserving in concentrated sulfuric acid at 80 degrees C for 1-8 hours, then washing the solution with water to make the pH of 6.8-7.2, and drying the product after washing to obtain a pre-oxidized graphite; (2) preparing and purifying graphene oxide; and (3) preparing iron(II,III) oxide magnetic nanospheres. USE - The method is useful for preparing graphene magnetic aerogel, which is useful for adsorption of pollutants such as dyes, organic solvents and heavy metal particles, and in sewage treatment. ADVANTAGE - The graphene magnetic aerogel has high adsorption performance and surface area. DETAILED DESCRIPTION - Preparing a graphene magnetic aerogel involves: (1) pre-oxidizing graphite by separately taking graphite powder, concentrated nitric acid, concentrated sulfuric acid and potassium permanganate in a mass ratio of (0.5-2):(0.5-2):(0.2-1.5):(0.2-1.5), adding to a reaction vessel, stirring and mixing to get a dark brown viscous liquid, washing the viscous liquid to pH of 6.8-7.2 and drying, then putting the dried material into a crucible with a temperature of 800-1000 degrees C, covering the crucible with a lid, cooling the crucible to room temperature to obtain an expanded graphite, then taking the expanded graphite, potassium persulfate and phosphorous pentoxide in a mass ratio of (1-5):(1-4):(1-4), heat preserving in concentrated sulfuric acid at 80 degrees C for 1-8 hours, then washing the solution with water to make the pH of 6.8-7.2, and drying the product to obtain a pre-oxidized graphite; (2) preparing and purifying graphene oxide by fully mixing the pre-oxidized graphite and sodium nitrate with concentrated sulfuric acid in a mass ratio of (0.1-1):(0.1-1), then stirring at 0-8 degrees C for 10-60 minutes, adding potassium permanganate to the pre-oxidized graphene in a mass ratio of (1-6):(0.1-1) to react for 20-100 minutes, then heating at 30-60 degrees C to continuously react for 10-100 minutes, adding 50-150 ml deionized water, then continuously heating at 80-100 degrees C, heat preserving and stirring for 10-40 minutes, when the reaction solution is cooled to room temperature, adding 150-300 ml deionized water and 1-10 ml 30% hydrogen peroxide solution to obtain a golden yellow graphene oxide solution, filtering, washing 2-7 times with deionized water and 5-10% hydrochloric acid, respectively, centrifuging 2-7 times the washed product under the condition of 1000-3000 rpm, and then carrying out dialysis purification treatment for 3-7 days to obtain a desired graphene oxide solution; (3) preparing iron(II,III) oxide magnetic nanospheres by taking ferric chloride hexahydrate, polyvinylpyrrolidone and anhydrous sodium acetate in a mass ratio of (1-5):(1-3):(2-4), mixing in the reaction vessel filled with ethylene glycol for 30-90 minutes, then placing the mixed solution in a stainless steel hydrothermal reactor, heat preserving at 170-250 degrees C for 5-15 hours, collecting the resulting product through an external magnet, then centrifuging 2-7 times the product at room temperature and 3500-4000 rpm for 4-15 minutes each time, and drying the centrifuged sample at 50-90 degrees C for 10-20 hours; and (4) mixing the graphene oxide solution, reducing agent and iron(II,III) oxide magnetic nanospheres in a mass ratio of (0.1-5):(0.01-0.1):(0.1-5), performing Solvothermal reaction under the condition of 80-100 degrees C to generate graphene magnetic hydrogel, then washing with 10-40 vol.% ethanol solution and freeze-drying.