Facile synthesis of carbon dots by the hydrothermal carbonization of avocado peels and evaluation of the photocatalytic property

Abstract

The preparation of carbon quantum dots (CQDs) from agricultural waste sources stands out as a significant type of biomass-based nanomaterials. This is primarily because of their minute size, exceptional water solubility, lack of toxicity, and impressive stability. Here, carbon quantum dots (CQDs) were successfully prepared by a one-step hydrothermal method using the waste from Avocado peels and only water as solvent. Physicochemical properties of the CQDs were characterized by UV–vis, PL, FTIR, XRD, SEM, TEM, and HRTEM. The diameter of the CQDs was found to satisfy the quantum size effect and this was also supported by the reduced graphitization. The CQDs were used for the removal of methyl orange (MO), a common anionic dye, from an aqueous solution. The effectiveness of MO removal was directly related to the pH and the amount of the nanomaterial used. Under optimal experimental conditions, with a 7.5 mg catalyst dose, a 120-minute reaction time, and a pH of 10, the maximum degradation of MO (78 %) was achieved.