Sintesis Nitrogen-Doped Carbon Dots (N-CDS) dengan Metode Hidrotermal dari Kulit Nangka dan Potensinya Sebagai Antibakteri

Abstract

This research aims to utilize jackfruit peel waste as a carbon source for synthesizing Carbon Dots (CDs) and Nitrogen-Doped Carbon Dots (N-CDs), as well as to evaluate the antibacterial potential of N-CDs. In the first stage, jackfruit peel was carbonized at 200°C for 2 hours. In the second stage, CDs and N-CDs were synthesized by combining 5 g of jackfruit peel powder with 2.5 g of urea as a nitrogen dopant through a hydrothermal method at 200°C for 8 hours. The mixture was then ultrasonicated for 30 minutes and centrifuged for 1 hour at a speed of 3000 rpm. The synthesized CDs and N-CDs were characterized using a UV lamp at 365 nm, UV-Visible spectroscopy, FTIR, Photoluminescence (PL) spectroscopy, and TEM. Characterization results showed that both CDs and N-CDs exhibit favorable fluorescence properties, evidenced by blue fluorescence when exposed to UV light at 365 nm. The UV-Vis absorbance peaks for CDs and N-CDs were observed at 269 nm and 278 nm, respectively. FTIR analysis identified the presence of O-H, C-H, C=O, C-O-C, and C-N-C groups in both samples, with the C-N group detected only in N-CDs, confirming successful nitrogen doping. PL tests revealed that adding urea enhanced the emission wavelengths of CDs and N-CDs from 492 nm to 494 nm, with quantum yield values of 3.09% and 9.51%, respectively. TEM analysis of N-CDs revealed spherical particles ranging from 7 to 9 nm in size, with an average diameter of 7.26 nm. Antibacterial tests demonstrated that N-CDs have potential as antibacterial, although the inhibition zones against Escherichia coli and Staphylococcus aureus were 2.3 mm and 1.75 mm, respectively, which fall into the weak category. When diluted with distilled water in a 1:2 ratio, N-CDs still exhibited antibacterial activity, but with smaller inhibition zones of 1.1 mm for both bacteria.