Synthesis of carbon nanodots from waste paper with hydrothermal method

Synthesis of C-Dots from waste paper has been successfully created. A total of 5 grams of waste paper is mixed with 40 mL aquades, 30 mL H₂SO₄ and 50 mL NaOH 2 M. A precursor solution is prepared by adding urea in 20 ml of material. Synthesis of C-Dots done by heating the precursor hydrothermally using a furnace with three conditions, namely with 1-4 grams of urea, 20-50 minutes of synthesis time, and 150-300°C of temperature. In a variation of urea and time, the temperature is controlled at 300°C. In a variation of the time and temperature, urea is controlled at 3 grams. In a variation of the urea and temperature, time is controlled for 30 minutes. The maximum absorption C-Dots generated on the various of amount urea, temperature, and synthesis time in the range of 360-600 nm. The width of the absorbance area was increased by adding 1-3 grams of urea and were decreased when urea is added 4 grams or more. The absorbance peaks of C-dots decreases with increasing temperature synthesis. Meanwhile, an increasing of synthesis time does not affect to the width of the absorbance spectra. It precisely causes decreasing of peaks of the absorbance spectra. The functional groups present on the surfaces of C-dots can be identified by the presence of specific peaks in their FTIR spectra, i.e. N–H, C=C, C–N, and C–C at various urea, N–H, C=O, C=C and C–O at temperature and synthesis time.