Solvent-Free Preparation of Tannic Acid Carbon Dots for Selective Detection of Ni2+ in the Environment

Abstract

Carbon dots (CDs) are widely used nanomaterials that not only exhibit good biocompatibility and photostability, but also benefit from a simple preparation process and easy functionalization, making them promising for broad applications in the fields of heavy metal ion detection and optoelectronic devices. Based on the excellent optical properties of CDs and the current situation of increasing energy shortages, this paper selects the natural polyphenolic compound tannic acid (TA) found in biomass materials as the carbon source and innovatively adopts a simple and convenient solvent-free pyrolysis method without auxiliary reagents or solvents. The CDs with good water solubility and certain fluorescence properties were directly prepared under the condition of high temperature, and the obtained CDs exhibited blue fluorescence, and a high QY of 35.4% was obtained at 300 °C. The analysis and results demonstrate the selectivity of these CDs for the detection of various metal ion solutions. In particular, these CDs are sensitive to Ni2+ and can be used as fluorescent sensors for the efficient and sustainable detection of Ni2+, whereas previous sensors were often specific to Fe3+ and Hg2+. Thus, a new sensing technique has been developed for the detection of Ni2+ to achieve more sensitive and rapid detection.

Preparation of Multicolor Fluorescent Carbon Dots Based on Catechol and o-Phthalaldehyde

“…In the ultraviolet absorption region, both the Y-CDs and G-CDs exhibit significant absorption peaks at 251 nm and 284 nm. The absorption peak at 251 nm corresponds to the π-π* transition of the C=C bond in the carbon nucleus, while the absorption peak at 284 nm corresponds to the n-π* transition of the C=C bond in the carbon nucleus [ 13 ]. In addition, distinct from the UV-Vis absorption spectra of Y-CDs and G-CDs, we observed that there was a characteristic absorption peak at 276 nm in the spectra of B-CDs, which corresponds to the B-absorption peak.…”

“…Researchers have gradually discovered that CDs have exceptional properties, including low toxicity, antibleaching, good biocompatibility [ 2 , 3 , 4 ], and excellent photostability [ 5 , 6 , 7 ]. These materials have received considerable attention in the field of nanomaterials, especially in biological imaging [ 8 , 9 ], drug release [ 10 , 11 ], fluorescent probes [ 12 , 13 ], optoelectronic devices [ 14 , 15 ], and other application fields. At present, various methods for synthesizing CDs have been developed, including laser ablation [ 16 ], chemical oxidation [ 17 ], microwave-assisted techniques [ 18 , 19 ], hydrothermal methods [ 20 , 21 ], electrochemical synthesis [ 22 , 23 ], and solution chemistry [ 24 ].…”

Carbon Dots—Types, Obtaining and Application in Biotechnology and Food Technology

“…Carbon dot based sensors are most commonly based on a fluorescence quenching mechanism induced by the surface states of the carbon dots. On this basis, metal ions such as Ag + [125], Fe 3+ [126], Hg 2+ [127], Cu 2+ [122], Ni 2+ [128] be detected. Ezati et al [129] have devised a method for detecting ammonia and its derivatives using specially prepared carbon dot-containing paper.…”

Recent trends in nanostructured carbon-based electrochemical sensors for the detection and remediation of persistent toxic substances in real-time analysis

“…Intensity, specificity, and reliability are the three most crucial factors to consider while investigating sensors. The types of energy transmission that sensors could detect include heat, electric and magnetic, electrochemical and mechanical [70][71][72][73][74]. Due to their extreme sensitivity and selectivity, electrochemical sensors stand out amongst them as particularly interesting analytical techniques.…”