Hydrothermal synthesis of carbon quantum dots from biowaste for bio-imaging

Carbon Quantum Dots (CQDs) is one of the new types of carbon-based nanomaterials which are rapidly gaining attention due to its excellent properties. In this study, a facile approach was used for synthesizing fluorescent carbon quantum dots using hydrothermal treatment of calamansi (Citrofortunella microcarpa) and pineapples (Ananas comosus) wastes as a carbon source. The carbon quantum dots were synthesized using a 2³ factorial design for the temperature, presence of TEPA, and acid type as the processing parameters to determine the best response. The composition and optical properties of the produced CQDs were characterized using a series of spectral analyses. The as-synthesized CQDs exhibited coagulation in aqueous solution and a strong blue fluorescence under UV light (λ= 365 nm). FTIR analysis confirmed the presence of functional group C-N on the surface of the CQDs which was more pronounced with the incorporation of TEPA.