▎ 摘　　要

NOVELTY - Preparing graphene-based hydrogel with three-dimensional network structure comprises (i) ultrasonically dispersing graphene oxide solution with a concentration of 10 mg/ml in deionized water and equipped with evenly dispersed and flocculent graphene oxide solution, (ii) adding tris(hydroxymethyl)aminomethane hydrochloride to the ultrasonically dispersed graphene oxide solution and stirring to dissolve, and keeps the solution pH weakly acidic using tris(hydroxymethyl)aminomethane hydrochloride, (iii) adding dopamine hydrochloride to mixed solution of step (ii), then stirring and dissolving, and (iv) hydrothermally reacting the above-mentioned uniformly mixed solution at high temperature, and then post-treating to obtain polydopamine-functionalized graphene-based hydrogel. USE - The graphene-based hydrogel with three-dimensional network structure is useful in water treatment including freshwater purification, seawater desalination and high-salt concentrated water desalination (claimed). ADVANTAGE - The method: has simple process, low cost, short cycle, low energy consumption and high repeatability; is easy to operate; and utilizes easily avialable raw materials. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for water treatment using graphene-based hydrogel with three-dimensional network structure comprising placing the graphene-based hydrogel on the surface of the volume of water for distillation, where the light time is 1-5 hours, light intensity is 1-7 kW/m2, the hydrogel extension height is 0-5 cm, and the salinity of the volume water is 0-14 wt.% sodium hydroxide.