Abstract: A preparation method of charcoal-based fertilizer is provided. Particularly, a special pig manure charcoal modified by amino grafting, a preparation method thereof, and its application in the reuse of nitrogen from farmland drainage are provided. The preparation method includes the following steps: 1) drying raw pig manure to a moisture content of 80%-85% and carrying out pickling, drying, and crushing successively to obtain a dried pig manure powder; 2) conducting liquid nitrogen pretreatment and high-temperature charcoalization to obtain an expanded pig manure charcoal; 3) performing carboxylation treatment to obtain a carboxylated pig manure charcoal; 4) amino grafting: adding an ammonia liquor to the carboxylated pig manure charcoal obtained in step 3), stirring for 20-24 h in an oil bath at 200-240° C.; washing and filtering; and drying and grinding to obtain the special pig manure charcoal modified by amino grafting.

Abstract: A preparation method of charcoal-based fertilizer is provided. Particularly, a special pig manure charcoal modified by amino grafting, a preparation method thereof, and its application in the reuse of nitrogen from farmland drainage are provided. The preparation method includes the following steps: 1) drying raw pig manure to a moisture content of 80%-85% and carrying out pickling, drying, and crushing successively to obtain a dried pig manure powder; 2) conducting liquid nitrogen pretreatment and high-temperature charcoalization to obtain an expanded pig manure charcoal; 3) performing carboxylation treatment to obtain a carboxylated pig manure charcoal; 4) amino grafting: adding an ammonia liquor to the carboxylated pig manure charcoal obtained in step 3), stirring for 20-24 h in an oil bath at 200-240° C.; washing and filtering; and drying and grinding to obtain the special pig manure charcoal modified by amino grafting.

Abstract: Disclosed is a method of preparing a carbon quantum dot from soybean dregs by hydrothermal synthesis, including: mixing the soybean dregs with water, and subjecting the reaction mixture under heating at 100-500° C. in an autoclave for reaction; cooling the reaction mixture when the reaction is completed, and removing insoluble substances from the reaction mixture; and dialyzing the reaction mixture, and lyophilizing the dialyzed product to produce the carbon quantum dot. The invention further provides the carbon quantum dot prepared by the above method and a use thereof in the detection of Fe3+ and Hg2+ in water, where the lowest detection limit can reach 30 nmol/L and the detection range is 0.1-50 ?mol/L.

Abstract: Disclosed is a method of preparing a carbon quantum dot from soybean dregs by hydrothermal synthesis, including: mixing the soybean dregs with water, and subjecting the reaction mixture under heating at 100-500° C. in an autoclave for reaction; cooling the reaction mixture when the reaction is completed, and removing insoluble substances from the reaction mixture; and dialyzing the reaction mixture, and lyophilizing the dialyzed product to produce the carbon quantum dot. The invention further provides the carbon quantum dot prepared by the above method and a use thereof in the detection of Fe3+ and Hg2+ in water, where the lowest detection limit can reach 30 nmol/L and the detection range is 0.1-50 ?mol/L.