▎ 摘　　要

NOVELTY - A titanium dioxide/graphene oxide small balls comprises alginate and graphene that is uniformly loaded on the balls, and has photocatalytic activity of nano-titanium dioxide. The titanium dioxide/graphene oxide balls are prepared by adding graphite powder, potassium persulfate and phosphorus pentoxide to 10-50 ml concentrated sulfuric acid at 50-100 degrees C for 2-8 hours, cooling, adding ultra-pure water, leaving still to obtain preoxidized graphite, adding preoxidized graphite to concentrated sulfuric acid, drying, adding sodium nitrate and potassium permanganate and reacting. USE - Load type titanium dioxide/graphene oxide small balls for photocatalytic reduction of hexavalent chromium ions (claimed). ADVANTAGE - The load type titanium dioxide/graphene oxide small balls has high adsorption ability and photocatalytic activity, with easy solid-liquid separation and reuse properties. DETAILED DESCRIPTION - The load type titanium dioxide/graphene oxide small balls comprises alginate and graphene that is uniformly loaded on the balls, and has photocatalytic activity of nano-titanium dioxide. The titanium dioxide/graphene oxide balls are prepared by (1) 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 mass ratio of graphite powder, potassium persulfate and phosphorus pentoxide is 1:(0.5-2):(0.5-2), concentration of concentrated sulfuric acid is 90-98%, cooling to 20-40 degrees C, adding 800-1200 ml ultra-pure water, leaving still for 8-12 hours, (2) adding preoxidized graphite obtained in step (1) to 200-300 ml concentrated sulfuric acid, drying at 40-80 degrees C, adding sodium nitrate and potassium permanganate, where concentration of concentrated sulfuric acid is 90-98%, where mass ratio of preoxidized graphite, potassium persulfate and phosphorus pentoxide is 1:(0.5-2):(10-50), reacting at 0-5 degrees C for 2-6 hours, heating at 30-40 degrees C, reacting for 1-4 hours, adding 200-800 ml ultra-pure water, heating at 80-100 degrees C for 1-6 hours, adding 800-1200 ml ultrapure water and 20-60 ml hydrogen peroxide, where concentration of hydrogen peroxide is 20-30%, reacting for 1-6 hours, washing product with 5-15% hydrochloric acid solution, washing with plenty of water to neutral, dispersing at 30-60 degrees C for 1-4 hours to obtain 1-10 mg/ml aqueous suspension of graphene oxide, (3) adding 10-300 ml aqueous suspension of graphene oxide with 100-2500 ml ultra-pure water, adding 1-25 g titanium dioxide, stirring, adding 1-30 g sodium alginate, heating, stirring, ultrasonically dispersing for 10-120 minutes to obtain mixture, (4) adding the mixture to 800-4000 ml calcium chloride solution using syringe to form balls having uniform size, where mass concentration of calcium chloride is 1-10%, reacting at room temperature for 2-12 hours, collecting balls, and washing several times. An INDEPENDENT CLAIM is included for use of load type titanium dioxide/graphene oxide balls in photocatalytic reduction of hexavalent chromium ions, which involves taking certain amount of hexavalent chromium wastewater, adjusting the pH value to 1-11, where mass concentration of the hexavalent chromium wastewater is 1-5000 mg/l, adding certain amount of balls to the waste water, wetting the balls so that weight is 1-100 g, performing reduction reaction under UV lamp irradiation, controlling reaction temperature at 10-50 degrees C, reaction time is 0-24 hours, and separating titanium dioxide/graphene oxide balls.