▎ 摘　　要

NOVELTY - Preparing nitrogen-doped graphene quantum dot hybrid film, comprises e.g. (1) dissolving citric acid and urea in water, stirring to form clear solution, adding into reaction kettle lined with polytetrafluoroethylene, heating; adding the reacted solution into petri dish, heating to dry, and taking out the dried solid, namely precursor material of nitrogen-doped graphene quantum dot N-GQDs; and (2) taking N-GQDs precursor powder, stirring to dissolve it with water, adding it to polyvinyl alcohol aqueous solution, stirring at room temperature, adding glutaraldehyde, ethyl orthosilicate, and silane coupling agent WD-51 to perform a sol-gel reaction to obtain hybrid precursor solution, continuously stirring; adding stirred solution into ultrasonic cleaner, carrying ultrasonic treatment to remove bubbles in the solution; allowing to stand and defoaming the obtained substance to obtain the coating film liquid. USE - The hybrid film is useful for adsorbing and separating copper ions from copper ion-containing wastewater, or selectively adsorbing and separating copper ions from mixed metal solution containing copper ions (claimed). DETAILED DESCRIPTION - Preparing nitrogen-doped graphene quantum dot hybrid film, comprises (1) dissolving citric acid and urea in water, stirring to form clear solution, where added amount is based on molar ratio of citric acid : urea = 1: 0.1-10, adding into reaction kettle lined with polytetrafluoroethylene, heating at 150-160 degrees C for 4-10 hours; adding the reacted solution into petri dish, heating to dry, and taking out the dried solid, namely precursor material of nitrogen-doped graphene quantum dot N-GQDs; (2) taking N-GQDs precursor powder, stirring to dissolve it with water, adding it to 5 wt.% polyvinyl alcohol aqueous solution, stirring at room temperature for 1-5 hours, adding glutaraldehyde, ethyl orthosilicate, and silane coupling agent WD-51 to perform a sol-gel reaction to obtain hybrid precursor solution, continuously stirring for 1-24 hours; adding stirred solution into ultrasonic cleaner, carrying ultrasonic treatment for 0.2-1 hours to remove bubbles in the solution; allowing to stand and defoaming the obtained substance to obtain the coating film liquid; or, taking N-GQDS precursor powder to mix water and stirring to completely dissolve, first, adding glutaraldehyde, orthodoxate, and silane coupling agent WD-51 to perform a sol-gel reaction, continuously stirring for 1-24 hours to obtain hybrid precursor solution; adding the hybrid precursor solution to polyvinyl alcohol aqueous solution (5 wt.%), stirring at room temperature for 1-5 hours, placing hybrid precursor solution in an ultrasonic cleaner under stirring conditions, carrying ultrasonic treatment for 0.2-1 hours to remove bubbles in precursor solution, allowing to stand and defoaming the obtained substance to obtain the coating film liquid; and (3) directly coating the coating film liquid to support to obtain membrane, placing 1-48 hours at room temperature, separating membrane from support, drying the membrane under 10-60 degrees C for 1-48 hours, cooling to obtain nitrogen-doped graphene quantum dot hybrid film without support body which is used for selectively adsorbing copper ions from mixed metal solution; or directly coating the coating film liquid to support to obtain membrane, drying the support and membrane at 10-60 degrees C for 1-48 hours, cooling to obtain nitrogen-doped graphene quantum dot hybrid film with support body which is used for selectively adsorbing copper ions from mixed metal solution; or dissolving coating film liquid with solvent, coating the resulting material to support to obtain membrane, drying the support and membrane together at 10-60 degrees C for 1-48 hours, cooling, to obtain the nitrogen-doped graphene quantum dot hybrid film with support body which is used for selectively adsorbing copper ions from mixed metal solution; or after drying, separating the membrane from support, namely obtaining nitrogen-doped graphene quantum dot hybrid film without support body which is used for selectively adsorbing copper ions from mixed metal solution.