Green synthesis of biomass derived carbon dots via microwave-assisted method for selective detection of Fe3+ ions in an aqueous medium

Heavy metal ion represents the most serious issues to the environment and human beings. Detection and removal of heavy metal ions in the water bodies are essential. Generally, carbon dots are used as a good fluorescence sensor to sense heavy metal ions. In the present study, Papaya seeds are successfully modified into water-soluble carbon dots by one-step microwave-assisted method. Synthesised carbon dots average size was about 1.45 nm with spherical shape analysed by HRTEM and the presence of decorated functional groups was analysed by FTIR. Papaya seeds carbon dots (PPYCDs) emit bright blue colour under UV radiation. PPYCDs emits a fluorescence emission peak at 405 nm with an excitation wavelength of 335 nm. PPYCDs have the greatest quenching efficiency with Fe3+ ions and display a rapid and good sensitivity due to the decorated functional groups present on them. The Fe3+ ions detection limit was about 2.35 μMol and these ecofriendly carbon dots being synthesised by a simple procedure without any complicated instrumentation and toxic reagents, paves a way for the sensor applications effectively.