A facile one-pot synthesis of fluorescent carbon dots from degrease cotton for the selective determination of chromium ions in water and soil samples

A highly fluorescent carbon dots were prepared by a facile one-pot hydrothermal method using degrease-cotton (human waste) as the carbon source. The structure and morphology of prepared C-dots were characterized by fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The as-prepared C-dots exhibit excellent emission property, high stability and have a narrow size distribution of 2-4 nm in diameter. Moreover, it is attractive that C-dots can be used as an effective fluorescent probe for the detection of chromium ions with good selectivity and sensitivity in an aqueous solution. The quenching phenomenon was observed after the C-dots interacted with the metal ions; and the results showed that the optimum conditions for its interaction with chromium ions were: 4.0 x 10(-5) g/mL of concentration of C-dots, pH =6.5 of buffer solution, and 20 min of time. Based on the optimum conditions, a new sensitive method detecting chromium ions was established. The method has been successfully applied to detect chromium ions in water and soil samples with satisfactory results.