▎ 摘　　要

NOVELTY - Preparation of graphene oxide-supported titanium dioxide coupling material, involves adding pre-oxidized graphite to concentrated sulfuric acid, adding sodium nitrate and potassium permanganate, and reacting, heating, adding ultra-pure water, reacting, adding ultra-pure water and hydrogen peroxide, reacting, washing the product with hydrochloric acid solution, then washing with plenty of water, ultrasonically dispersing to obtain oxidized graphene suspension, adding ethanol to oxidized graphene suspension, stirring, adding mixture of tetraisopropyl titanate and ethanol and stirring. USE - Preparation of graphene oxide-supported titanium dioxide coupling material used for removing hexavalent chromium in wastewater (claimed), and treatment of electroplating, leather tanning, printing and dyeing wastewater. ADVANTAGE - The preparation method of coupling material is simple and easy to realize industrial production. The prepared coupling material has excellent photocatalytic activity of titanium dioxide and the adsorption performance of graphene oxide, and effectively removes hexavalent chromium in wastewater. The product can be used for electroplating, leather tanning, printing and dyeing wastewater treatment. DETAILED DESCRIPTION - Preparation of graphene oxide-supported titanium dioxide coupling material, involves (i) adding graphite powder, potassium persulfate and phosphorus pentoxide to 10-50 mL concentrated sulfuric acid at 50-100 degrees C for 2-8 hours where the mass ratio of graphite powder, potassium persulfate and phosphorus pentoxide is 1:(0.5-2):(0.5-2) and mass concentration of concentrated sulfuric acid is 90-98%, and then cooling to 20-40 degrees C, adding 800-1200 mL ultra-pure water, maintaining for 8-12 hours, washing the product to neutral and then drying at 40-80 degrees C to obtain pre-oxidized graphite, (ii) adding pre-oxidized graphite to 200-300 mL concentrated sulfuric acid, then adding sodium nitrate and potassium permanganate where the mass concentration of concentrated sulfuric acid is 90-98% and the mass ratio of pre-oxidized graphite, sodium nitrate and potassium permanganate is 1:(0.5-2):10-50, and performing reaction at 0-5 degrees C for 2-6 hours, heating at 30-40 degrees C for 1-4 hours, adding 200-800 mL ultra-pure water, reacting at 80-100 degrees C for 1-6 hours, then adding 800-1200 mL ultra-pure water and 20-60 mL hydrogen peroxide having concentration of 20-30%, continuing the reaction for 1-6 hours, washing the resulting product with hydrochloric acid solution having a mass concentration of 5-15%, and then washing with plenty of water to neutral, and ultrasonically dispersing at 30-60 degrees C for 1-4 hours to obtain oxidized graphene suspension having mass concentration of 1-10 mg/mL, (iii) adding 10-1000 mL ethanol to 10-1000 mL of oxidized graphene suspension obtained in step (ii), transferring the mixture to a water bath and stirring at a temperature of 5-60 degrees C for 1-100 minutes, slowly adding mixture of 5-60 mL tetraisopropyl titanate and 1-500 mL ethanol to the obtained mixture, stirring at 5-60 degrees C for 0.5-10 hours, then evaporating ethanol and water in the gel at 50-100 degrees C to obtain a light gray powder, drying the resulting powder at 10-100 degrees C for 2-24 hours, then grinding to obtain graphene oxide-supported titanium dioxide coupling material. An INDEPENDENT CLAIM is included for method for removing hexavalent chromium in wastewater using graphene oxide-supported titanium dioxide coupling material, which involves taking certain volume of hexavalent chromium wastewater with mass concentration of 1-200 mg/L, adding sodium hydroxide or hydrochloric acid to hexavalent chromium wastewater to adjust the pH value to 1-11, adding a certain amount of graphene oxide-supported titanium dioxide coupling material to the hexavalent chromium wastewater where the mass concentration of the coupling material in the solution is 0.1-10 g/L, fully contacting and reacting graphene-supported titanium dioxide coupling material and hexavalent chromium wastewater at 10-50 degrees C for 0.5-5 hours under the no light conditions, and then placing quartz glass with UV lamp in hexavalent chromium wastewater, stirring evenly the wastewater for 1-24 hours, and reacting, separating the graphene oxide-supported titanium dioxide coupling material from the solution by a filter after the reaction is completed, and determining hexavalent chromium remaining in the solution by UV spectrophotometry.