▎ 摘　　要

NOVELTY - Composite hydrogel comprises titanium nanotubes dispersed on the surface of graphene oxide. USE - Composite hydrogel for removing tetracycline in waste water (claimed). ADVANTAGE - The composite hydrogel is prepared in simple and cost effective manner using raw materials that are cheap and easily available. The method involves no organic solvents in preparing composite hydrogel and is suitable for industrial production. The composite hydrogel has high adsorption selectivity. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing composite hydrogel which involves: (A) dissolving graphene oxide in water; (B) sonicating the mixture; (C) adding titanium nanotubes to the graphene oxide solution; (D) sonicating mixture for 36-48 hours to obtain a titanium nanotubes-graphene mixed solution; (E) mixing 10 mL of titanium nanotubes-graphene oxide mixed solution with 0.5 mL of 40 mg/mL vitamin C; (F) stirring for 3-4 minutes; and (G) heating mixed solution in water bath at 85-90 degrees C for 6-8 hours to obtain titanium nanotube-graphene oxide hydrogel.