▎ 摘　　要

NOVELTY - Preparing core-shell graphene oxide quantum dot zero-valent iron catalyst comprises e.g. (1) adding graphite powder and concentrated sulfuric acid with a concentration of 98 wt.% in sequence, and the dosing ratio is 30-35 ml concentrated sulfuric acid per gram of graphite powder, and reacting in ultrasonic reactor for 30 minutes under ice bath conditions, adding sodium nitrate and potassium permanganate, stirring for 150 minutes, and the mass ratio of graphite powder, sodium nitrate and potassium permanganate is 4:5:16, heating to 96-98℃, adding deionized water, and stirring for 30 minutes, and (2) adding deionized water, 30% hydrogen peroxide and hydrochloric acid, thermally insulating, reacting for 10 minutes, maintain yellowish brown sticky substance at the bottom, allowing it settle, and pouring off supernatant, adding deionized water, pouring off acid-containing supernatant, repeating for 8-10 times until neutral. USE - The method is useful for preparing core-shell graphene oxide quantum dot zero-valent iron catalyst, which is useful as catalyst for removing refractory wastewater. ADVANTAGE - The method overcomes defect that zero-valent iron particle is easy to agglomerate and fast oxidation, enhances catalytic activity of composite material, and has good application prospect. DETAILED DESCRIPTION - Preparing core-shell graphene oxide quantum dot zero-valent iron catalyst comprises (1) adding graphite powder and concentrated sulfuric acid with a concentration of 98 wt.% in sequence, and the dosing ratio is 30-35 ml concentrated sulfuric acid per gram of graphite powder, and reacting in ultrasonic reactor for 30 minutes under ice bath conditions, adding sodium nitrate and potassium permanganate, stirring for 150 minutes, and the mass ratio of graphite powder, sodium nitrate and potassium permanganate is 4:5:16, heating to 96-98°C, adding deionized water, and stirring for 30 minutes, (2) adding deionized water, 30% hydrogen peroxide and hydrochloric acid, thermally insulating, reacting for 10 minutes, maintain yellowish brown sticky substance at the bottom, allowing it settle, and pouring off supernatant, adding deionized water, pouring off acid-containing supernatant, repeating for 8-10 times until neutral, (3) centrifuging yellow-brown viscous matter after ultrasonic reaction to obtain a yellow-brown precipitate and drying, using dried tan solid as a precursor and water as a solvent to prepare a tan solid and aqueous solution with a mass ratio of 1:500-600, and adjusting pH with 0.1 mol/l sodium hydroxide solution, transferring to reaction kettle, heating at rate of 4°C/minute, and thermally insulating for 30 minutes, reacting, cooling, concentrating and centrifuging filtered solution to obtain a graphene oxide quantum dot solution, (4) ultrasonically reacting graphene oxide quantum dot solution for 30 minutes, dissolving anhydrous ferric chloride in deionized water, mixing, maintaining pH at 11-12, and the temperature at 28-30℃, adding aminopropyltriethoxysilane and stirring, introducing nitrogen as a protective gas, adding deionized aqueous solution of sodium borohydride, and stirring until the amount of hydrogen generated is ≮ 1 ml/minute, performing centrifugation, using oxygen-free deionized water and oxygen-free absolute ethanol to centrifuge for 2-3 times to obtain a core-shell graphene oxide quantum dot zero-valent iron solution, drying, and obtain core-shell graphene oxide quantum dots zero-valent iron catalyst, and (5) adding hydrogen peroxide solution and catalyst to refractory wastewater, adjusting dosage of catalyst and hydrogen peroxide, and staying in reaction tank for 40 minutes.