The invention provides a method for extracting fluorescent
carbon quantum dots from semi
coke. The method comprises the following steps: firstly, adding semi
coke powder into a 4M to 6M
nitric acid solution, and carrying out stirred refluxing at the temperature of 80 DEG C to 120 DEG C; carrying out natural cooling, then, carrying out
centrifugation for 30 minutes to 60 minutes at the rate of 10,000r / min to 15,000r / min, collecting supernatant, removing precipitates, and
drying the obtained supernatant by
distillation in a reduced-pressure
distillation manner, so as to obtain black solids; dispersing the black solids in deionized water, carrying out neutralizing by
ammonia water, then, carrying out
centrifugation for 30 minutes to 60 minutes at the rate of 10,000r / min, and collecting supernatant; dialyzing the supernatant by
dialysis bags, collecting solutions in the
dialysis bags, and carrying out
vacuum drying for 24 hours to 48 hours at the temperature of 60 DEG C to 80 DEG C, thereby obtaining the
carbon quantum dots. According to the method, the semi
coke which is low in cost and easy in
raw material obtaining is adopted as a
carbon source, and the
carbon quantum dots can be obtained through simple chemical oxidation,
evaporation,
neutralization,
centrifugation and
dialysis treatment processes. The carbon
quantum dots have the particle size of 3nm to 5nm and are uniform in dispersion, and surfaces of the carbon
quantum dots have a large number of carboxyl groups and hydroxyl groups, so that a relatively good fluorescent property is shown.