Extensive accumulation of waste tires, which is hard to decompose naturally, have led to serious resource waste and environmental pollution. Carbon element, primarily contained in waste tire, making them an ideal precursor for the synthesis of carbon dots. N-doped carbon dots (N-CDs) were synthesized by acid-free one-step hydrothermal synthesis method using waste tires powder pyrolysic carbon black (CBp) as carbon source and ammonium persulfate (APS)-triethanolamine (TEA) oxidation-reduction system as oxidant and N element as doping agent, respectively. The synthesis conditions of N-CDs were optimized by orthogonal experiments, while the composition, structure and fluorescence properties of N-CDs were characterized by FTIR, XPS, TEM and steady-state fluorescence spectrometer. A fluorescent ink for anti-counterfeiting was further prepared from N-CDs and evaluated for its performance. The results showed that N-CDs exhibited a basic spherical structure with a particle size of 3~6 nm. Under excitation at 325 nm, N-CDs displayed a maximum fluorescence emission intensity at 410 nm, indicating its wavelength-dependent fluorescence emission property. The photoluminescence quantum yield of N-CDs was 5.14%, which was 12.5 times higher than that of carbon dots (CDs) synthesized by chemical oxidation method using nitric acid as oxidant. The anti-counterfeiting fluorescent ink emitted blue-green fluorescence under a 365 nm UV light, and luminescence phenomenon still remained stable and obvious after 7-day storage.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |