Eco-Friendly Synthesis of Green Fluorescent Carbon Quantum Dots derived from Phoenix dactylifera fruit for Mn²⁺ Detection and Efficient Photocatalytic Degradation of Organic Dyes

Manganese contamination in potable water and the persistence of synthetic dyes in wastewater represent urgent environmental and public health challenges. Herein, a sustainable, low-cost strategy is reported for dual-function environmental remediation using green-emissive carbon quantum dots (CQDs) derived from Phoenix dactylifera (date-palm) fruit via a simple reflux synthesis. The CQDs exhibited strong photoluminescence with emission peaks at 430 nm (blue) and 538 nm (green). Comprehensive spectroscopic and microscopic analyses confirmed their structural and optical properties. Notably, the CQDs demonstrated remarkable selectivity and sensitivity toward Mn²⁺ ions with a detection limit of 0.21 ppm, making them promising candidates for water quality monitoring. Additionally, the CQDs effectively adsorbed Methyl Red (MR) and Methylene Blue (MB) following Langmuir and pseudo-second-order kinetics, and exhibited superior photocatalytic degradation efficiencies (>85%) under sunlight. These findings underscore the potential of P. dactylifera-derived CQDs as multifunctional nanomaterials for environmental sensing and wastewater treatment.