Glutathione assisting the waste tobacco leaf to synthesize versatile biomass-based carbon dots for simultaneous detection and efficient removal of mercury ions

High-efficient conversion of the waste biomass into eco-friendly novel bifunctional materials for selective monitoring and effective removal of mercury ions (Hg 2+ ) is of great significance to achieve the environment sustainable development, but has not attracted enough attention. Herein, we exploited glutathione (GSH) assisting waste tobacco leaf as the biomass-related precursors to successfully yield a novel red fluorescence emission biomass-based carbon nanodots (CDs) with a remarkably large Stokes shift of ~ 232 nm through one-pot hydrothermal method. Owing to the synergistic Hg-S bond and the coordination effects of the Hg 2+ to the abundant –COOH, –NH 2 and –OH groups on the surface of CDs, this proposed biomass-based CDs showed a red fluorescence decrease response for Hg 2+ with a high selectivity and a lower detection limit of 0.45 μM in environmental water samples. Furthermore, this binding endowed this proposed biomass-based CDs possessed a high removal efficiency of above 99.4% for Hg 2+ as well. This work showed a novel insight into recycling the waste tobacco leaf into novel, economic, efficient, reliable, and eco-friendly biomass-based CDs for simultaneously precise traceability and high-efficient removal of Hg 2+ pollution in environmental matrices. • A biomass-based N, S-codoped CDs with a red fluorescence emission (~ 652 nm) was synthesized by employing waste tobacco leaf as the precursor. • The sensitive detection of Hg 2+ with LOD of 0.45 μM was achieved by using the CDs. • Hg 2+ could be removal with a high efficiency of 99.4% by using the CDs. • The interaction between the CDs and Hg 2+ was revealed to be the synergistic Hg-S bond and the coordination effects.