▎ 摘　　要

NOVELTY - Chitosan-polydopamine-graphene hydrogel adsorbing material comprises mercaptochitosan, dopamine hydrochloride and biomass-based porous graphene at 5-20:1 mass ratio. USE - Used as chitosan-polydopamine-graphene hydrogel adsorbing material. ADVANTAGE - The biomass-based porous graphene has rich porous structure. The polydopamine nanoparticle is uniformly grown in the porous graphene large specific surface and pore structure. The hydrogel adsorbing material has abundant pore structure, large amount of amino, carboxy and hydroxy groups, and strong complexation adsorption capacity with chromium ion (Cr4+) and rhodamine B. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the chitosan-polydopamine-graphene hydrogel adsorbing material comprising centrifuging and separating egg white liquid of egg, placing the separated protein in deionized water solvent, adding ascorbic acid, putting in constant temperature reactor, heating at 25-45 degrees C, stirring for 5-10 hours until forming colloid, adding graphene oxide and urea, stirring to form gel, conducting freezing-thawing treatment of the gel-like product by freezing at - 15 to - 25 degrees C, thawing at 25-35 degrees C, and repeating freezing-thawing treatment for 2-4 times, uniformly mixing the solid product and potassium hydroxide solution, putting in hydrothermal reaction kettle, reacting for 2-4 hours at 160-180 degrees C, putting the solid mixed product in atmosphere furnace, heating at 2-10 degrees C/minute, raising the temperature to 700-800 degrees C under argon atmosphere, keeping the temperature and calcining for 2-3 hours, and obtaining biomass-based porous graphene; adding into deionized water, ultrasonically dispersing uniformly, adding tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) solution and adjusting the pH of the solution at 8.5, reacting for 20-30 hours at 20-40 degrees C, filtering, washing and drying, and obtaining nano-polydopamine grafted porous graphene; adding phosphoric acid (H3PO4), chitosan and sodium nitrate (NaNO2) into concentrated nitric acid (HNO3), controlling HNO3, H3PO4 and NaNO2 ratio at 2-2.5:1:0.2-0.4, reacting for 1-3 hours at 40-70 degrees C, adding sodium hydroxide to adjust the pH of the solution at 5-6, adding deionized water until there is a large amount of precipitates, and obtaining carboxylated chitosan; adding into deionized water, ultrasonically dispersing uniformly, adding cystamine dihydrochloride, activating agent 1-hydroxy-7-azabenzotriazole and condensing agent 1-ethyl-(3-dimethylaminopropyl)carbonyldiimide hydrochloride, reacting for 10-20 hours, centrifuging and separating, washing and drying to prepare cystamine chitosan; adding into ethanol solvent, ultrasonically dispersing uniformly, adding dithiothreitol, reacting for 15-25 hours, centrifugally separating, washing and drying, and obtaining thiolated chitosan; and adding nano-polydopamine grafted porous graphene and thiolated chitosan into dimethyl sulfoxide solvent, reacting for 15-30 hours at 30-60 degrees C until there is a large amount of gel-like product, washing and dialyzing.