▎ 摘　　要

NOVELTY - The extraction of graphene quantum dots from coffee grounds solid waste involves adding recovered coffee residue to dilute hydrochloric acid, stirring, carrying out ultrasonic surface activation, filtering, washing with deionized water, washing solid coffee grounds in distilled water, ultrasonically dispersing, adding aqueous ammonia and hydrazine hydrate mixture, stirring, reacting, taking out and naturally cooling, filtering residual black solid, dispersing strong fluorescent graphene quantum dots in deep brown filtrate, transferring to dialysis bag for dialysis and drying. USE - Extraction of environmentally-friendly graphene quantum dots from coffee grounds solid waste (claimed). ADVANTAGE - The method enables extraction of environmentally-friendly graphene quantum dots from coffee grounds solid waste with readily available and inexpensive material by simple process, and achieves low energy consumption. DETAILED DESCRIPTION - The extraction of graphene quantum dots from coffee grounds solid waste involves adding 1 g recovered coffee residue to 80 ml concentration of 0.05-0.1 mol/l dilute hydrochloric acid, stirring, carrying out ultrasonic surface activation for 2-20 hours, stopping ultrasonically treating process, filtering, washing repeatedly with deionized water until the pH of filtrate coffee grounds reaches to 7, washing solid coffee grounds in 100 ml distilled water, ultrasonically dispersing, adding 1-10 ml aqueous ammonia and 5-40 ml hydrazine hydrate mixture (solution of pH is not less than 12), stirring, putting in Teflon (RTM: PTFE) reactor, reacting at 120-200 degrees C for 5-20 hours, taking out and naturally cooling, filtering with 25 nm filter, filtering residual black solid, stably dispersing large number of strong fluorescent graphene quantum dots in the deep brown filtrate, transferring to dialysis bag for dialysis after the filtration of the solution is completed and drying the solution at 120 degrees C.