Open AccessHydrothermal oxidation method to synthesize nitrogen containing carbon dots from compost humic acid as selective Fe(III) sensor
Author(s) -
Yan Zhu,
Ying Bao,
Liping Wang,
Jingtao Bi,
Yong Liu,
Chuang Xie
Publication year - 2020
Publication title -
materials research express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 35
ISSN - 2053-1591
DOI - 10.1088/2053-1591/abb5f1
Subject(s) - x ray photoelectron spectroscopy , quantum yield , photoluminescence , aqueous solution , humic acid , fluorescence , fourier transform infrared spectroscopy , carbon fibers , materials science , spectroscopy , analytical chemistry (journal) , chemistry , quenching (fluorescence) , nuclear chemistry , inorganic chemistry , chemical engineering , fertilizer , environmental chemistry , organic chemistry , composite number , engineering , composite material , physics , optoelectronics , quantum mechanics
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.