Effect of Urea and Chitosan Doping on Red Bean Carbon Dots as Heavy Metal Detectors

Abstract

The synthesis of red bean carbon dots doped with urea and chitosan has been successfully carried out using the bottom-up method via hydrothermal technique at 200°C for 4 hours. UV-VIS characterization showed that Carbon Dots : Red Beans + NaOH had an absorbance value of 2.55, Carbon Dots : Red Beans + NaOH + Urea had an absorbance value of 1.55, while Carbon Dots :Red Beans + Urea + Chitosan had an absorbance value of 2.66. FTIR characterization shows that the Carbon Dots do not change in spectral wave number with wave numbers 3265 cm -1 to 1021 cm -1 . Microstructure of Red Beans + NaOH Carbon Dots has a spherical microstructure with a diameter of between 7-12 nm, and Red Beans + NaOH + Urea Carbon Dots has a cubical microstructure. Meanwhile, Carbon Dots from Red Beans + Urea + Chitosan have a spherical microstructure with a diameter of 6 - 9 nm. The EDX characterization shows that the Carbon Dots sample contains the elements C, O, K, Cl, Na.