▎ 摘　　要

NOVELTY - Preparing graphene oxide-magnetic nanocomposite, comprises e.g. adding iron(II) chloride tetrahydrate and 8-10 g of ferric chloride hexahydrate into water, adding sodium hydroxide solution to the mixed solution, stirring the mixed solution, placing the stirred mixture in a water bath, adding concentrated nitric acid into stirred mixture, stirring the mixed solution, adding sodium citrate solution to the mixture to stir, cooling and washing the solution with absolute ethyl alcohol, centrifuging to collecting magnetite and then drying in an oven to obtain a magnetite nanoparticle. USE - USE u The graphene oxide-magnetic nanocomposite is useful for monitoring polycyclic aromatic hydrocarbon pollutant. ADVANTAGE - The method provides graphene oxide-magnetic nanocomposite with high quality and safety in a simple and environmentally friendly manner. DETAILED DESCRIPTION - Preparing graphene oxide-magnetic nanocomposite, comprises: (a) adding 3-5 g of iron(II) chloride tetrahydrate and 8-10 g of ferric chloride hexahydrate into 100-200 ml of water, adding 12-15 ml of sodium hydroxide solution with a concentration of 10-30 mole/l to the mixed solution, stirring the mixed solution at a room temperature for 1-5 hours, placing the stirred mixture in a water bath at 60-90 degrees C, continuously stirring the mixture for 1-5 hours, adding 0.3-1 ml of concentrated nitric acid with a mass density of 69.8% into stirred mixture, continuously stirring the mixed solution for 0.5-3 hours, adding 50-150 ml of sodium citrate solution with a mass density of 0.3-1 mole/l to the mixture, stirring the solution for 0.5-3 hours, cooling and washing the solution with absolute ethyl alcohol for 3-5 times, centrifuging and collecting the magnetite from the solution, and drying the magnetite in an oven at a temperature of 80 degrees C to obtain a magnetite nanoparticle; (b) mixing 150-200 ml of absolute ethyl alcohol with 30-50 ml of water, adding 0.1-0.5 g of the magnetite nanoparticle into the solution, mixing and stirring the mixture and adding 5-10 ml of ammonia water with a mass density of 20-40% into the mixed solution, processing the mixed solution under ultrasonic condition for 1-5 hours, dropwisely adding 500-1000 mu l of covering material into the processed solution and then stirring, reacting the mixture for 12-48 hours, washing the reacted mixture with absolute ethyl alcohol for 3-5 times, centrifuging the mixture to collect product, and drying the product into dryer at 80 degrees C to obtain a modified magnetic nanoparticle; (c) dissolving 20-100 mg of graphite oxide into 50-100 ml of dimethyl formamide, adding 0.5-1 g of modified magnetic nanoparticle, adding 20-100 mg of N,N-dicyclohexylcarbodiimide into mixed solution, stirring the mixture for 24-48 hours, placing the stirred solution in water bath at the temperature of 50-80 degrees C, centrifuging and collecting the solid product from the mixture, washing the solid product with water and methanol for 3-5 times to remove redundant graphite oxide, and drying the washed solid product using an oven at 80 degrees C to obtain a graphene oxide magnetic nanoparticle; and (d) adding 0.1-1 g of graphene oxide magnetic nanoparticle and 0.1-1 ml of hydrazine hydrate with a mass density of 60-85% into water, reacting the mixture in water bath at a temperature of 70-98 degrees C for 2-5 hours, centrifuging and collecting the solid product from reacted mixture, washing the solid product with water and methanol for 3-5 times, and placing the washed solid product into an oven at a temperature of 80 degrees C for drying.