Carbon dots capped cerium oxide nanoparticles for highly efficient removal and sensitive detection of fluoride

Since the excess exposure to F- may induce serious issues to human health, the effective adsorption and sensitive detection of F- is essential. Therefore, carbon dots (CDs) capped CeO2 (CeO2@CDs) was synthesized via hydrothermal treatment of tannic acid and CeCl3. Due to abundant phenolic hydroxyl are reserved and excellent hydrophilicity, CeO2@CDs possess high F- adsorption capacity. The partition coefficient parameters (PC) are determined to be 2.65 L/g, which is comparable with previous work. The kinetics results and adsorption isotherm are consistent with pseudo-second-order model and Freundlich model, respectively, indicating the chemisorption dominate the adsorption, mainly via the ion exchange between hydroxyl and F-. Since phenolic hydroxyl existed on the CeO2@CDs, synergetic effect of CDs and CeO2 contribute to superior ROS eliminating capacity, even at acidic conditions. Moreover, due to the ROS scavenging of CeO2 @CDs abilities can be potentiated by F-, colorimetric detection of F- can be realized via horseradish peroxidase as an indicator. The linear range is 0.3-2.1 mM with limit of detection is 0.13 mg/L. The current results imply that CeO2@CDs possess potential in both efficient removal and sensitive detection of F- related contamination issues and elucidation of development to address other anions related issues.