Abstract:
Renewable biowaste-derived carbon dots have garnered immense interest owing to their
exceptional optical, fluorescence, chemical, and environmentally friendly attributes, which have been
exploited for the detection of metals, non-metals, and organics in the environment. In the present
study, water-soluble fluorescent carbon dots (CDs) were synthesized via facile green microwave
pyrolysis of pine-cone biomass as precursors, without any chemical additives. The synthesized
fluorescent pine-cone carbon dots (PC-CDs) were spherical in shape with a bimodal particle-size
distribution (average diameters of 15.2 nm and 42.1 nm) and a broad absorption band of between
280 and 350 nm, attributed to a - * and n- * transition. The synthesized PC-CDs exhibited the
highest fluorescent (FL) intensity at an excitation wavelength of 360 nm, with maximum emission of
430 nm. The synthesized PC-CDs were an excellent fluorescent probe for the selective detection of
Cu2+ in aqueous solution, amidst the presence of other metal ions. The FL intensity of PC-CDs was
exceptionally quenched in the presence of Cu2+ ions, with a low detection limit of 0.005 g/mL; this
was largely ascribed to Cu2+ ion binding interactions with the enriched surface functional groups on
the PC-CDs. As-synthesized PC-CDs are an excellent, cost effective, and sensitive probe for detecting
and monitoring Cu2+ metal ions in wastewater.
