Hydrothermal oxidation method to synthesize nitrogen containing carbon dots from compost humic acid as selective Fe(III) sensor. (16th September 2020)

• Record Type: Journal Article
• Authors: Zhu, Yan; Bao, Ying; Wang, Liping; Bi, Jingtao; Liu, Yong; Xie, Chuang
• Is Part Of: Materials research express. Volume 7:Number 9(2020)
• Publication Date: 2020-09-16
• Subjects: iron ion probe -- fluorescence quenching -- humic acid -- sludge -- nitrogen containing carbon dots; Materials science -- Research -- Periodicals; Materials science -- Periodicals; 620.11
• DOI: 10.1088/2053-1591/abb5f1
• Languages: English
• ISSNs: 2053-1591

Abstract

Abstract: Residual sludge which is generated as a by-product during wastewater treatment needs efficient and environmentally friendly disposal. In this work, nitrogen containing carbon dots (N-CDs) was synthesized via one-step hydrothermal oxidation of humic acid for the first time, which was alkalinely extracted from the compost of sludge. The successful doping of the functional groups (hydroxyl, carboxyl and amino) on the surface of N-CDs were characterized by x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The optical properties of the synthetic N-CDs were obtained from Ultraviolet-visible spectroscopy and Photoluminescence spectra. The N-CDs had an average diameter at 1.88 nm and exhibited a well-defined spherical shape. The aqueous solution of N-CDs with excitation-dependent properties showed a strong blue emission with 8.8% quantum yield (QY) under an excitation wavelength of 340 nm, which indicate the synthesized N-CDs a promising sensing probes for iron ions in aquatic system. Moreover, the mechanism of the N-CDs sensing technique was investigated in detail, which can be explained by the fluorescence static quenching effect and a ground-state complex formed in this process. This research demonstrates an extremely sensitive method for detecting heavy metal Fe 3+ at a lower 1.9 nM level by using N-CDs as fluorescent probes without a complicated procedure.