EUBCE 2026 - Tong LIN - Hydrothermal Intensification of Biomass to Fluorescent Carbon Quantum Dots: Process Design for High-Value Bio-Chemicals

Hydrothermal Intensification of Biomass to Fluorescent Carbon Quantum Dots: Process Design for High-Value Bio-Chemicals

Short Introductive summary

Fluorescent carbon quantum dots (CQDs) are high-value biochemicals used as nano-catalysts, security inks, bio-sensors and fluorescent probes, but their production from lignocellulosic waste is hindered by a yield–quantum-yield (QY) trade-off. We developed an intensified hydrothermal platform comparing one-step versus two-step protocols combining acid, alcohol or oxidant cleavage without post-doping. Sixty-four feedstock–solvent–process combinations (4 biomass × 2 routes × 8 solvents) were screened at 200 °C, 12 h. Rice straw, bamboo dust, coffee spent and ryegrass were processed either by one-step solvent-thermal carbonization or by two-step pre-depolymerisation (70 °C) followed by carbonization. Absolute yield (AY) and QY were determined gravimetrically and against quinine-sulfate standard, respectively. First full-factorial dataset shows record native QY = 13.61 % (coffee, one-step 4 mL H2O2) at AY = 0.48 wt %, and maximum AY = 7.96 wt % (coffee, two-step ethanol) with QY = 2.82 %. Experimental validation demonstrates that the process exhibits good reproducibility and structural consistency, with the prepared carbon quantum dots showing excellent fluorescent performance.

T. Lin, Southeast University, Nanjing, Jiangsu Province, P.R. CHINA
D. Shen, Southeast University, Nanjing, Jiangsu Province, P.R. CHINA