▎ 摘　　要

NOVELTY - Composite hydrogel is prepared from inorganic nanoparticles, graphene oxide, epichlorohydrin, perchloric acid, and natural polysaccharides, where the natural polysaccharide substance is chosen from at least one of chitosan and konjac glucomannan. USE - The composite hydrogel is used in water treatment (claimed). ADVANTAGE - The composite hydrogel has network structure and high mechanical strength, has excellent water absorption, magenta, methyl orange adsorption and reusability, and absorbs most of the heavy metal ions. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the composite hydrogel, comprising (a) preparing graphene oxide by using Hummers method, (b) dissolving epichlorohydrin, perchloric acid, ethanol and water, adding natural polysaccharide substances and toluene, carrying out reflux reaction at 90-100 degrees C for 2-4 hours, filtering, washing the filter cake with ethanol, and drying at 40-60 degrees C to obtain the solid powder N-(3-chloro-2-hydroxy) propyl sugar, dissolving graphene oxide in water, adding sodium carbonate and N-(3-chloro-2-hydroxy) propyl sugar, carrying out reflux reaction for 1-2 hours, filtering, washing the filter cake with distilled water, and drying at 40-60 degrees C to obtain a bonded natural polysaccharide substance, and (c) adding inorganic nanoparticles to water, continuously adding bonding natural polysaccharide substances, stirring for 20-30 minutes, standing for 1-3 minutes, pouring, and standing for 24-48 hours to obtain the composite hydrogel.