Versatile Coffee Carbon Dots as Lead (ii) and Copper (ii) ion Fluorescence Detectors and Copper Corrosion Inhibitor

A simple and green tandem hydrothermal and pyrolysis method was developed for the synthesis of blue fluorescence carbon dots from coffee green bean powder and urea as raw materials. The carbon dots were characterized by ultraviolet visible spectrophotometer, Fourier-transform infrared spectroscopy and ocean optics spectrophotometer. The carbon dots had a bright blue emission centered at 505 nm under UV light with the excitation wavelength at 360 nm. The carbon dots also showed a quenching effect with lead (ii) ions and copper (ii) ions. Furthermore, a method for copper (ii) and lead (ii) ion detection in aqueous solution was developed with acceptable linearity of 97.26% and 99.41% respectively and selectivity to some common ions. The carbon dots also demonstrated the ability to act as copper corrosion inhibitors in 1% sodium chloride solution showing an inhibition efficiency of 77% at 1000 ppm. It is worth noting that the synthesized fluorescent carbon dots are eco-friendly and inexpensive. They could find application in chemical sensing and copper corrosion inhibition in salt environments.

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Study on Photocatalytic Properties of La–Nd/ZnO in UV-vis Region and Possibility of Large-Scale Effluent Treatment Containing Reactive Dyes

NANO ◽

10.1142/s1793292021500739 ◽

2021 ◽

pp. 2150073

Author(s):

Liuqi Cao ◽

Liming Wang ◽

Mingrui Xie ◽

Yong Shen ◽

Lihui Xu ◽

...

Keyword(s):

Large Scale ◽

Uv Light ◽

Raw Materials ◽

Reactive Dyes ◽

Effluent Treatment ◽

Excitation Wavelength ◽

X Ray ◽

Compound Material ◽

Visible Irradiation ◽

Nanometer Zinc Oxide

Flower-shaped nanometer zinc oxide and its complex incorporating La–Nd have been prepared using hydrothermal method with zinc chloride and urea as raw materials, ethylene glycol as morphology controller. The powdered samples were characterized by scanning electron microscopy, X-ray diffractometry, photocatalytic test with solutions of reactive dyes as indicators. In conclusion, the optimum doping ratios of La/Nd are considered to be 3%/3%. When 3%La–3%Nd/ZnO was served as photocatalyst, considerable degradations of dyes were caused under the ultraviolet and visible light without exception, owing to the expanded excitation wavelength and reduced band gap of ZnO after incorporating. While using the compound material in effluent treatment containing reactive dyes, the decomposition rate of dyes, respectively, reached 99.99% and 80% or more under UV-light and visible irradiation for 60 min, appreciable removal effects of organic pollutants were obtained, testifying 3%La–3%Nd/ZnO to be a splendid UV-Vis catalyst.

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High Quantum Yield Fluorescent Chitosan-Based Carbon Dots for the Turn-On-Off-On Detection of Cr(VI) and H2O2

NANO ◽

10.1142/s1793292021501034 ◽

2021 ◽

pp. 2150103

Author(s):

Yudong Zhang ◽

Yan Dong ◽

Haifu Zheng ◽

Xueyun Yang ◽

Cheng Yao

Keyword(s):

Quantum Yield ◽

Carbon Dots ◽

Blue Emission ◽

Inner Filter Effect ◽

Hydrothermal Carbonization ◽

Reduction Reaction ◽

High Quantum Yield ◽

One Pot ◽

Quenching Effect ◽

High Quantum

One-pot hydrothermal carbonization approach was employed to synthesize the blue-emission carbon dots derived from chitosan (Cs) and o-phenylenediamine (OPD). The Cs-based carbon dots (Cs–CDs) possessed a certain high quantum yield of 58% and exhibited excellent solubility, stability and fluorescence response in aqueous solutions. The Cs–CDs were designed as a sensor for Cr(VI) and H2O2 determination. The sensing strategy of Cr(VI) was based on the inner filter effect (IFE) and static quenching effect (SQE), showing a good linear correlation ranging from 1 to 130[Formula: see text][Formula: see text]M with a detection limit (LOD) of 0.91[Formula: see text][Formula: see text]M. In addition, the determination for H2O2 was attributed to the elimination of IFE (EIFE) due to the reduction reaction and the detection for H2O2 was in the linear range from 1.0 to 200.0[Formula: see text][Formula: see text]M with LOD of 0.51[Formula: see text][Formula: see text]M. Finally, the proposed designed sensor could be simply applied for detection of Cr(VI) and H2O2 in real samples.

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Ratiometric and selective fluorescent nanosensor for the detection of glucose

Current Chinese Chemistry ◽

10.2174/2666001601666210106121954 ◽

2021 ◽

Vol 01 ◽

Author(s):

Shengda Qi

Keyword(s):

Limit Of Detection ◽

Blue Emission ◽

Glucose Sensing ◽

Excitation Wavelength ◽

Dual Emission ◽

Fluorescent Intensity ◽

Quenching Effect ◽

Color Evolution ◽

Nanocomposite System ◽

Dual Emissions

Background and Methods: Dual-emission fluorescent nanosensor for the detection of glucose has been developed by simply mixing the blue-emission C-dots (CDs) with red-emission glutathione modified CdTe QDs. Results and Discussion: The ratiometric fluorescence system exhibits dual emissions peak at 442nm and 600 nm under a single excitation wavelength (365 nm). Due to the strong quenching effect of hydrogen peroxide to the quantum dots, the fluorescence of the QDs in the nanocomposite system could be selectively quenched by H2O2, while the fluorescence of the CDs remained constant, resulting in a distinguishable fluorescence color evolution (from red to blue) of the nanosensor which could be observed obviously by the naked eye. When this nanosensor mixed with glucose oxidase, H2O2 can be produced by the enzyme catalysis reaction, which could quench the fluorescent intensity of QDs. So this system can be used to detect glucose. The limit of detection of this present method was as low as 0.1 μM. Conclusion: the result for glucose was satisfying, suggesting its potential application for glucose sensing.

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Detection of nitrite based on fluorescent carbon dots by the hydrothermal method with folic acid

Royal Society Open Science ◽

10.1098/rsos.172149 ◽

2018 ◽

Vol 5 (5) ◽

pp. 172149 ◽

Cited By ~ 9

Author(s):

Haitao Lin ◽

Liyun Ding ◽

Bingyu Zhang ◽

Jun Huang

Keyword(s):

Hydrothermal Method ◽

Carbon Dots ◽

Nitrite Concentration ◽

One Pot ◽

Quenching Effect ◽

Transmission Electron ◽

The Relationship ◽

Fluorescent Carbon Dots ◽

Hydrolysis Of ◽

Fluorescent Carbon

A fluorescent carbon dots probe for the detection of aqueous nitrite was fabricated by a one-pot hydrothermal method, and the transmission electron microscope, X-ray diffractometer, UV–Vis absorption spectrometer and fluorescence spectrophotometer were used to study the property of carbon dots. The fluorescent property of carbon dots influenced by the concentration of aqueous nitrite was studied. The interaction between the electron-donating functional groups and the electron-accepting nitrous acid could account for the quenching effect on carbon dots by adding aqueous nitrite. The products of the hydrolysis of aqueous nitrite performed a stronger quenching effect at lower pH. The relationship between the relative fluorescence intensity of carbon dots and the concentration of nitrite was described by the Stern–Volmer equation ( I 0 / I − 1 = 0.046[ Q ]) with a fine linearity ( R 2 = 0.99). The carbon dots-based probe provides a convenient method for the detection of nitrite concentration.

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A Review of Fluorescent Carbon Dots, Their Synthesis, Physical and Chemical Characteristics, and Applications

Nanomaterials ◽

10.3390/nano11061448 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1448

Author(s):

Mychele Jorns ◽

Dimitri Pappas

Keyword(s):

Carbon Dots ◽

Hydrothermal Carbonization ◽

Quantitative Information ◽

Fluorescent Imaging ◽

Excitation Wavelength ◽

Cell Type ◽

Different Types ◽

Biological Environment ◽

Physical And Chemical ◽

Fluorescent Carbon Dots

Carbon dots (CDs) are a particularly useful type of fluorescent nanoparticle that demonstrate biocompatibility, resistance to photobleaching, as well as diversity in composition and characteristics amongst the different types available. There are two main morphologies of CDs: Disk-shaped with 1–3 stacked sheets of aromatic carbon rings and quasi-spherical with a core-shell arrangement having crystalline and amorphous properties. They can be synthesized from various potentially environmentally friendly methods including hydrothermal carbonization, microwaving, pyrolysis or combustion, and are then purified via one or more methods. CDs can have either excitation wavelength-dependent or -independent emission with each having their own benefits in microscopic fluorescent imaging. Some CDs have an affinity for a particular cell type, organelle or chemical. This property allows the CDs to be used as sensors in a biological environment and can even provide quantitative information if the quenching or intensity of their fluorescence is dependent on the concentration of the analyte. In addition to fluorescent imaging, CDs can also be used for other applications including drug delivery, quality control, photodynamic therapy, and photocatalysis.

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A Short Report on the Polymerization of Pyrrole and Its Copolymers by Sonochemical Synthesis of Fluorescent Carbon Dots

Polymers ◽

10.3390/polym11081240 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1240 ◽

Cited By ~ 7

Author(s):

Moorthy Maruthapandi ◽

Aharon Gedanken

Keyword(s):

Carbon Dots ◽

Solid State Nmr ◽

Uv Light ◽

Analytical Techniques ◽

Short Report ◽

X Ray Diffraction ◽

X Ray ◽

Polymeric Chains ◽

Fluorescent Carbon Dots ◽

Scientific Aspect

In polymer chemistry, polymerization constitutes the process of the conversion of monomers into polymers using an initiator to form polymeric chains. There are many polymerization techniques and different systems exist by which the polymers are classified. Recently, our group has reported the synthesis of polymers using both carbon dots (CDs) and UV light as initiators. In these reports, the carbon dots were used with or without UV light. The CDs produce free radicals in the presence of UV light, indicating their role as initiators. The CD surface has many unshared or unpaired electrons, making it negatively charged. The present study focuses on the use of CDs for the formation of polymers from monomers containing various functional group. The properties of the synthesized CDs and the polymers obtained from the various monomers were characterized by various analytical techniques, including Fourier-Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Solid-State NMR spectroscopy. This polymerization technique is of interest both from the scientific aspect and for its applicative potential. The synthesized polymers were investigated for their various applications.

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Highly Fluorescent Carbon Dots as a Potential Fluorescence Probe for Selective Sensing of Ferric Ions in Aqueous Solution

Chemosensors ◽

10.3390/chemosensors9110301 ◽

2021 ◽

Vol 9 (11) ◽

pp. 301

Author(s):

Raji Atchudan ◽

Somasundaram Chandra Kishore ◽

Thomas Nesakumar Jebakumar Immanuel Edison ◽

Suguna Perumal ◽

Rajangam Vinodh ◽

...

Keyword(s):

Aqueous Solution ◽

Carbon Dots ◽

Fluorescence Probe ◽

Synthesis Method ◽

Blue Emission ◽

Spherical Shape ◽

Average Diameter ◽

Excitation Wavelength ◽

X Ray ◽

Fluorescence Characteristics

This paper’s emphasis is on the development of a fluorescent chemosensor for Fe3+ ions in an aqueous solution, using hydrophilic carbon dots (O-CDs). A simple, cost-effective, and environmentally friendly one-step hydrothermal synthesis method was used to synthesize fluorescent hydrophilic O-CDs from Oxalis corniculata (Family; Oxalidaceae). The graphitic structure and size distribution of the O-CDs was verified by X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy studies. The resulting O-CDs had a near-spherical shape and an adequate degree of graphitization at the core, with an average diameter of 4.5 nm. X-ray photoelectron and Fourier transform infrared spectroscopy methods revealed the presence of several hydrophilic groups (carbonyl, amine, carboxyl, and hydroxyl, along with nitrogen and oxygen-rich molecules) on the surface of O-CDs. The synthesized hydrophilic O-CDs with excitation wavelength-dependent emission fluorescence characteristics showed a high quantum yield of about 20%. Besides this, the hydrophilic O-CDs exhibited a bright and controllable fluorescence with prolonged stability and photo-stability. These fluorescent hydrophilic O-CDs were used as a nanoprobe for the fluorometric identification of Fe3+ ions in an aqueous solution, with high sensitivity and selectivity. By quenching the blue emission fluorescence of this nanosensor, a highly sensitive Fe3+ ion in the range of 10–50 µM with a minimum detection limit of 0.73 µM was achieved. In addition, the developed nanosensor can be used to sense intracellular Fe3+ ions with high biocompatibility and cellular imaging capacity, and it has a lot of potential in biomedical applications.

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Synthesis of Carbon Dots via Hydrothermal Reaction for Selective Detection of Serotonin

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17646 ◽

2020 ◽

Vol 20 (9) ◽

pp. 5365-5368

Author(s):

Yeji Kim ◽

Jongsung Kim

Keyword(s):

Carbon Dots ◽

Hydrothermal Reaction ◽

Limit Of Detection ◽

Uv Light ◽

Aqueous Solubility ◽

Excitation Wavelength ◽

Blue Color ◽

Cobalt Ions ◽

Doped Carbon Dots ◽

Nitrogen Doped Carbon

Serotonin (5-HT) is a significant neurotransmitter involved in the regulation of mood, social behavior, depression, and other neurological activities. In this work, we synthesized nitrogen-doped carbon dots using naturally occurring amino acids such as L-aspartic acid and L-cysteine by employing a one-step hydrothermal reaction. The amino acid-derived carbon dots (CDs) are called AACDs. The as-synthesized AACDs showed strong blue-color emission under UV light and photoluminescence (PL) emission maximum wavelength at 457 nm with an excitation wavelength of 344 nm. The AACDs had superior aqueous solubility due to the carboxyl (–COOH) and amine (–NH2) functional groups on their surface. 5-HT could be detected by adding cobalt ions (Co2+) to the AACDs. The Co2+ ions facilitate cross-linking between free amino and carboxylate groups. Fluorescence quenching by AACDs incorporating Co2+ ion was observed to be dependent on the concentration of serotonin. The limit of detection (LOD) of AACDs for 5-HT was 2.24 μM.

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A Novel Nitrogen-Doped Dual-Emission Carbon Dots as an Effective Fluorescent Probe for Ratiometric Detection Dopamine

NANO ◽

10.1142/s1793292021500302 ◽

2021 ◽

pp. 2150030

Author(s):

Jianliang Bai ◽

Xu Chen ◽

Guojun Yuan ◽

Lu Zhang ◽

Zhujun Huang ◽

...

Keyword(s):

Carbon Dots ◽

Uv Light ◽

Dual Emission ◽

Nitrogen Doped ◽

Ratiometric Detection ◽

Orange Fluorescence ◽

New Type ◽

Doped Carbon Dots ◽

Nitrogen Doped Carbon ◽

Fluorescent Carbon Dots

Fluorescent carbon dots (CDs) as a new-type kind of zero-venami material have attracted growing interest. Herein, we developed a novel and convenient method to prepare dual emission nitrogen-doped carbon dots (N-CDs). Under ultraviolet (UV) light, N-CDs show blue and orange fluorescence centered at 435[Formula: see text]nm and 595[Formula: see text]nm, respectively. Because the two emission peaks of N-CDs exhibit different sensitivity to dopamine (DA), the N-CDs can serve as ratiometric fluorescent probes for DA measurement. The ratio ([Formula: see text]/[Formula: see text]) exhibits good linear relationship with DA concentration within the scope of 45–80[Formula: see text][Formula: see text]M. The quenching mechanism of N-CDs toward DA is also proposed, and it is suggested that the quenching may start because by the electrostatic interaction between N-CDs and DA.

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Nitrogen-doped carbon dots from Hutai-8 grape skin and their application in Hg2+ detection

Current Nanoscience ◽

10.2174/1573413716999200819201126 ◽

2020 ◽

Vol 16 ◽

Author(s):

Pan Zhang ◽

Shun-Sheng Zhao ◽

JiaJia Wang ◽

Xiang Rong Liu

Keyword(s):

Heavy Metal ◽

Carbon Source ◽

Fluorescence Quenching ◽

Hydrothermal Method ◽

Water Samples ◽

Carbon Dots ◽

Mercury Ions ◽

Grape Skin ◽

Fluorescent Carbon Dots ◽

Fluorescent Carbon

Background: In recent years, environmental pollution and heavy metal pollution caused by rapid urbanization and industrialization have become increasingly serious. Among them, mercury (II) ion (Hg2+) is one of the highly toxic heavy metal ions, and its pollution comes from various natural resources and human activities. Therefore, people attach great importance to the development of analytical methods for effective analysis and sensitive detection of Hg2+ . Objective: Using grape skin as a green and environmental friendly carbon source, to synthesize fluorescent carbon dots, and try to apply them to the detect the concentration of Hg2+ in water. Method: Using "Hutai No. 8" grape skin as carbon source, fluorescent carbon dots were synthesized by one-step hydrothermal method. Structure and fluorescent properties of the carbon dots were tested using TEM, XPS, XRD and other characterization instruments, and their utilization on detection of mercury ions in the actual water samples was explored. Results: The CDs had a particle size of about 4.8 nm and a spherical shape. There are N-H, C-N, C=O and other functional groups on the surface. It was found that Hg2+ has obvious fluorescence quenching effect on CDs, and thus CDs fluorescence quenching method to detect the concentration Hg2+ was established, and the detection limit is 3.7 μM, which could be applied to test the concentration of Hg2+ in water samples. Conclusion: Using grape skin as carbon source, fluorescent carbon dots were successfully synthesized by hydrothermal method. Carbon dots were used to detect mercury ions in water, and a method for detecting mercury ions in actual water samples was established.

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