Dual-emissive waste oil based S-doped carbon dots for acetone detection and Cr(VI) detection/reduction/removal

• Published in: Journal of environmental chemical engineering 2023-04, Vol.11 (2), p.109438, Article 109438
• Main Authors: Rangel, Miriam, Saluja, Sarvagya, Barba, V., Pérez-Huerta, J.S., Agarwal, V.
• Format: Article
• Language: English
• Subjects: Acetone detection; Canola oil; Cr(III); Cr(VI) reduction; Dual optical sensor; Sulfur doped carbon dots
• ISSN: 2213-3437
• DOI: 10.1016/j.jece.2023.109438

Dual-emissive water-dispersible sulfur-doped carbon dots (S-CDs) were prepared through simple heat treatment of canola oil as a carbon source. The S-CDs revealed excitation wavelength-dependent and independent emission band in UV (327 nm) and the visible region (633 nm), respectively. The fluorescent S-CDs ranged from 4 to 9 nm in size and exhibited selectivity and linear “turn-off” fluorescence in the presence of Cr(VI) and acetone, making them potential nanosensors for their detection. Concentration-dependent red-shift of the S-CDs emission spectrum was observed in the presence of acetone, via incremental quenching of the peaks at 327 nm and 633 nm, accompanied by an emergence of new peak at adjacent higher wavelength. Linearity was observed in the range of 0.01–0.08 vol%, with a limit of detection (LOD) of 0.01 vol%. The nanoprobe was tested in spiked tap and river water for Cr(VI) along with acetone detection assays in spiked human urine and phosphate buffer solution. XPS analysis revealed the reduction of Cr(VI) to Cr(III) in the presence of S-CDs, a less toxic form. In addition to the optical detection, fluorescent probes incorporated into poly vinyl alcohol (PVA) matrix could be used for the removal of Cr(VI) ions from the contaminated water. Hence, the proposed S-CDs have potential applications as highly sensitive, selective, cost-effective, and environmental friendly sensors of acetone and Cr(VI), as well as for developing tools for the reduction and removal of Cr(VI) from contaminated water. [Display omitted] •Canola oil derived S-doped carbon dots as dual-emissive optical nanoprobes.•S-CDs as optical sensor (turn-off) for Cr (VI) with 20 nM limit of detection (LOD).•Detection of Cr (VI) is accompanied with its reduction to less toxic form Cr (III).•Removal of Cr(VI) ions from water using S-CDs/PVA composites demonstrated.•Dual detection of acetone demonstrated and tested in spiked human urine sample.