Sustainable Green Synthesis of Carbon Nanodots From <i>Gloriosa superba</i> Flower for Selective Sensing of Cr <sup>6+</sup> Ions in the Environmental Water Samples
Abstract
This study highlights the biogenic synthesis of fluorescent carbon nanodots (CNDs) derived from Gloriosa superba floral precursor‐based carbon dots for the selective sensing of environmental metal pollutants. The CNDs were synthesized using a simple and eco‐friendly hydrothermal method and characterized through Uv–vis spectroscopy, fluorescence spectroscopy, Fourier‐transform infrared (FTIR), XRD, X‐ray photoelectron spectroscopy (XPS), and high resolution transmission electron microscopy (HRTEM) analyses. FTIR and XPS results confirm the presence of oxygen‐ and nitrogen‐containing functional groups, indicating successful heteroatom doping on the CNDs surface. The XRD pattern exhibited a broad diffraction peak around 2θ° ≈ 22°, characteristic of the amorphous carbon structure of the nanodots. HRTEM images revealed uniformly dispersed spherical nanoparticles with average size of ~3 nm. The synthesized CNDs demonstrated strong green photoluminescence with a relative quantum yield of ±17%, excellent water solubility, and good biocompatibility. Additionally, antioxidant and genotoxicity assays indicated the nontoxic and biologically safe nature of the material. Among the tested metal ions, the GS‐CNDs exhibited remarkable selectivity and sensitivity toward hexavalent chromium (Cr 6+ ), with a detection limit of 0.45 μM attributed to fluorescence quenching. Overall, the Gloriosa superba flower derived CNDs offer a sustainable green nanomaterial for sensitive Cr 6+ detection and hold strong potential for future application in environmental water analysis.