Plastic bags were used to produce carbon dots (CDs), which can contribute to solving environmental problems.
The enhanced quantum yield (QY) was achieved in this study through the passivation of CDs with sulfur (S) and
nitrogen (N). Pyrolysis and hydrothermal methods were used to produce S-N co-doped CDs (S-N-CDs) from
plastic bags. Notably, S-N-CDs significantly enhanced the QY to 16.20 %. The resulting S-N-CDs retained
remarkable fluorescence performance over high ionic strengths and UV light irradiation. The incorporation of
functional groups containing oxygen, sulfur, and nitrogen in S-N-CDs created recognition sites that enable
specific and highly selective sensing of Fe3+ ions, with a quenching ability of up to 62 %. Moreover, these S-NCDs displayed a wide linearity in the range of 110.64–600 µM for Fe3+ ion detection. The sensing system
exhibited exceptional performance in detecting Fe3+ in actual water samples with %Recovery of 90–100 % and %
RSD below 0.39 %, The findings highlight the prospect of S-N-CDs from plastic bags as promising sensors for
future environmental analysis, addressing the urgent need for effective and sustainable solutions.
