▎ 摘　　要

NOVELTY - Preparation of graphene oxide-TiO2 composite material comprises taking graphene oxide, adding ethanol/water at volume ratio of 350:25, ultrasonic dispersing, forming suspension of graphene oxide, stirring, oil bath heating at 80 degrees C; mixing titanium butoxide and ethanol/sulfuric acid at volume ratio of 25:0.375, adding into suspension oxidized graphene at titanium butoxide and titanium dioxide mass ratio of 1:1-9, heating at 80 degrees C, stirring; and centrifuging, ultra-pure water washing and drying. USE - Method for preparing graphene oxide-TiO2 composite material used for separation/enrichment of heavy metal ions (all claimed). ADVANTAGE - The method optimizes synthesis of composite material, and increases efficiency of separation/enrichment of sediment heavy metals and rare earth elements in environmental water samples. The material has good adsorption rate, large adsorption capacity, high selectivity, strong anti-interference ability and long life. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) preparation of graphene oxide comprising taking 2.5 g potassium persulfate and 2.5 g phosphorus pentoxide, adding 12 mL concentrated sulfuric acid, adding 3 g graphite, dispersing uniformly, heating at 80 degrees C for 4.5 hours, standing overnight, filtering, cooling, water washing until neutral, vacuum drying at 40 degrees C to get pre-oxidized graphite; dispersing in 120 mL concentrated sulfuric acid, adding potassium permanganate under ice bath, reacting at not less than 20 degrees C, stirring at 35 degrees C for 7 days; adding 250 mL deionized water, cooling to less than 50 degrees C, heating up to 98 degrees C, stirring for 2 hours, placing reaction liquid in beaker, adding 0.7 L deionized water, ending reaction; adding 20 mL 30 vol.% hydrogen peroxide solution, reducing permanganate and manganese dioxide to manganese ions, magnetic stirring for 2 hours, standing overnight; and draining upper layer solution, washing remaining solids with 1.3 L 10 vol.% hydrochloric acid, centrifuging, washing using deionized water until neutral, and freeze-drying; and (2) separation/enrichment of heavy metal ions comprising taking 30-50 mg graphite oxide-TiO2 composite material, placing in PTFE microcolumn, filling ends of the column with cotton to prevent oxidation of graphene composites, fastening screw cap; cleaning using 0.1 mol/L nitric acid and 0.1 mol/L ammonium acetate, adjusting pH to 3-10, enriching solution containing heavy metal ion using 0.3-1 mol/L nitric acid solution and eluting.