The invention discloses a method for high efficiency preparation of
carbon quantum dots by using
biomass soot, wherein the method comprises the following specific steps: 1, adding concentrated
nitric acid and concentrated
sulfuric acid or a mixture of the two components into
soot obtained by burning
biomass, and carrying out ultrasonic treatment for 1 h-5 h, to obtain a dispersion liquid of the
soot; 2, carrying out heating treatment of the dispersion liquid of the soot for 10-36 h at the temperature of 80 to 120 DEG C, naturally cooling to
room temperature, then placing the cooled product into
ice water, adding ultra pure water, stirring, and adjusting the
mixed solution to be neutral with K2CO3, to obtain a crude product; and 3, centrifuging the crude product to filter out a precipitate, carrying out grading
dialysis of the filtrate by using
dialysis bags with different
cut-off molecular weights, concentrating dialysates of all parts, and thus obtaining carbon
quantum dot solutions with different size ranges. The selected raw materials are low in price and stable in sources, the preparation process is simple, and obtained
carbon quantum dots can emit yellow
fluorescence, have high
quantum yield, and are suitable for light electric conversion,
biological imaging,
ion sensing and other fields.