▎ 摘　　要

NOVELTY - Preparing polyvinyl alcohol/carboxymethyl chitosan/graphene oxide composite nanofiber membrane comprises (1) dissolving polyvinyl alcohol in deionized water with stirring while heating to obtain a polyvinyl alcohol solution, (2) dissolving carboxymethyl chitosan in deionized water to obtain carboxymethyl chitosan solution, (3) using graphite, potassium permanganate, concentrated sulfuric acid and hydrogen peroxide as raw materials and oxidizing by improving the Hummers method, (4) stirring and mixing polyvinyl alcohol solution, carboxymethyl chitosan solution and graphite oxide aqueous dispersion in a mass ratio of 7:3:1-12, obtaining composite spinning solution, and electrostatic spinning the composite spinning solution to obtain a composite fiber membrane, and (5) thermally crosslinking the above-mentioned composite fiber membrane in a vacuum oven, then crosslinking in glutaraldehyde vapor. USE - The nanofiber membrane is used in adsorption of heavy metal ions, preferably nickel ions, copper ions, silver ions and/or lead ions. ADVANTAGE - The nanofiber membrane has large specific surface area, high porosity, large efficient contact area with heavy metal ions, good adsorption capacity for various heavy metal ions, the adsorption capacity can reach 230-410 mg/g, and the time to reach adsorption equilibrium is short, so it has a good application prospect for treating heavy metal wastewater. DETAILED DESCRIPTION - Preparing polyvinyl alcohol/carboxymethyl chitosan/graphene oxide composite nanofiber membrane comprises (1) dissolving polyvinyl alcohol in deionized water with stirring while heating to obtain a polyvinyl alcohol solution, (2) dissolving carboxymethyl chitosan in deionized water to obtain carboxymethyl chitosan solution, (3) using graphite, potassium permanganate, concentrated sulfuric acid and hydrogen peroxide as raw materials and oxidizing by improving the Hummers method, allowing to stand the oxidized product, high-speed centrifuging at 12000-20000 revolutions per minute and freeze-drying to obtain yellow-brown airgel-type graphite oxide, placing the graphite oxide in deionized water, and ultrasonically treating in an ice-water bath with a power of 20000 HZ to obtain a graphite oxide aqueous dispersion, (4) stirring and mixing polyvinyl alcohol solution, carboxymethyl chitosan solution and graphite oxide aqueous dispersion in a mass ratio of 7:3:1-12, obtaining composite spinning solution, and electrostatic spinning the composite spinning solution to obtain a composite fiber membrane, and (5) thermally crosslinking the above-mentioned composite fiber membrane in a vacuum oven, then crosslinking in glutaraldehyde vapor, and then vacuum-drying at 25°C for 10-14 hours to obtain final product. An INDEPENDENT CLAIM is also included for polyvinyl alcohol/carboxymethyl chitosan/graphene oxide composite nanofiber membrane prepared by the above preparation method.