Usage of coconut coir for sustainable production of high-valued carbon dots with discriminatory sensing aptitude toward metal ions

A novel, remunerative, green synthetic methodology without adding any kind of extra chemical reagent has been proposed for synthesizing highly fluorescent carbon dots (C-dots) by using waste coconut coir as the C source. The as-prepared C-dots possessed a quantum yield of 48% and displayed a high solubility rate in aqueous media. The fluorescence emission intensity of C-dots is found to be excitation dependent with high stability toward variation in the reaction medium. The bio-congenial performance of C-dots has been checked by employing quantitative multi-assay including fungus, plant, aquatic animals, and at the chromosomal level. It is notable that the antibacterial studies of as-prepared C-dots have presented appealing outcomes which advocated that C-dots prepared using coconut coir are biocompatible toward both Gram-positive and Gram-negative bacteria with no zone of inhibition in much higher concentration ranges. The as-prepared C-dots provided a simple sensing podium with high sensitivity and selectivity with a "turn-on and turn-off" fluorescence response for the detection of dual metal ions i.e. cadmium and copper ions in aqueous media with a detection limit of 0.18 nM and 0.28 nM, respectively. The practical utilities of the biocompatible C-dots have been checked over different water resources. The current work provided a simple, easy, bio-matched, harmless, rapid, and cost-effective sensory probe for wastewater remediation.