▎ 摘　　要

NOVELTY - The preparation method of magnetic graphene-based zinc oxide nano-composite material involves ultrasonically dispersing graphene oxide in deionized water to obtain graphene oxide suspension, dissolving sodium nitrite in water to obtain sodium nitrite aqueous solution, cooling, adding sulfanilic acid and hydrochloric acid aqueous solution, and reacting under ice water bath condition to obtain aryl diazonium salt, dissolving sodium borohydride in water to obtain sodium borohydride aqueous solution, and adjusting the pH value of the graphene oxide suspension. USE - Preparation method of magnetic graphene-based zinc oxide nano-composite material for degrading organic pollutants such as methylene blue in water (claimed). ADVANTAGE - The method enables preparation of magnetic graphene-based zinc oxide nano-composite material with excellent photocatalytic degrading performance and regeneration performance. DETAILED DESCRIPTION - The preparation method of magnetic graphene-based zinc oxide nano-composite material involves (1) ultrasonically dispersing 60 mg graphene oxide in 60 ml deionized water to obtain graphene oxide suspension with concentration of 1 mg/ml, dissolving 42 mg sodium nitrite in 25 g water to obtain sodium nitrite aqueous solution, cooling to 0-5 degrees C, adding 110 mg sulfanilic acid and 1 ml 1 mol/l hydrochloric acid aqueous solution, and reacting under ice water bath condition for 30 minutes to obtain aryl diazonium salt, dissolving 320-400 mg sodium borohydride in 15-20 ml water to obtain sodium borohydride aqueous solution, adjusting the pH value of the graphene oxide suspension to 9-10 with 5 wt.% sodium carbonate aqueous solution, adding sodium borohydride aqueous solution, uniformly stirring at 75-85 degrees C for 1-2 hours, cooling to room temperature after the reaction is finished, ultrasonically stripping for 10-30 minutes, dripping aryl diazonium salt under stirring condition, reacting for 1-3 hours under ice water bath and room temperature conditions, dialyzing against deionized water until the pH value is 7, and ultrasonically treating for 15-30 minutes to obtain sulfonated graphene aqueous solution, (2) adding cobalt(II) chloride hexahydrate and iron(III) chloride hexahydrate according to cobalt ion and ferric ion molar ratio of 2:1 into deionized water to obtain mixed liquid, adding the mixed liquid to sulfonated graphene aqueous solution to obtain graphene mixed liquid, adjusting the pH value of the graphene mixed liquid to greater than or equal to 11 using 15-30 %mass aqueous ammonia, transferring the graphene mixed liquid into a reactor within 15-30 minutes, ultrasonically treating at 100-150 degrees C for 3-5 hours, cooling to room temperature, and washing with anhydrous ethanol and water to obtain magnetic graphene, and (3) adding zinc nitrate hexahydrate to the magnetic graphene aqueous solution obtained in the step (2) according to mass ratio of zinc nitrate hexahydrate and magnetic graphene (20-1):1, adjusting the pH value to 11 using 25% concentrated ammonia, ultrasonically dispersing for 1 hour, adding the obtained mixed liquid into the reactor, hydrothermally reacting at 160-200 degrees C for 10-12 hours, cooling the mixed solution to room temperature, and washing with water and anhydrous ethanol. An INDEPENDENT CLAIM is included for use of magnetic graphene-based zinc oxide nano-composite material in sewage treatment, which involves adding magnetic graphene-based zinc oxide nano-composite material to an aqueous solution containing methylene blue or methyl orange organic dye, where the mass ratio of magnetic graphene-based zinc oxide nano-composite material with the organic pollutant is (80-120):1, oscillating for 15-30 minutes so that the organic pollutant with magnetic graphene-based zinc oxide nano-composite material reaches the adsorption and desorption balance with wavelength of 365 nm, UV light irradiating for 1.5-3 hours, photodegrading the organic dye in water, magnetically separating the magnetic graphene-based zinc oxide nano-composite material in the mixed solution, recycling and reusing.