Rapid and simple preparation method of lignin-based carbon quantum dots with high quantum yield

A technology based on carbon quantum and lignin, which is applied in the field of fluorescent carbon quantum dot preparation, can solve the problems of low fluorescence quantum yield of products, inability to prepare in large quantities, and complicated preparation process, so as to achieve cheap and easy-to-obtain materials and benefit large-scale production. Scale promotion, good water solubility

Active Publication Date: 2021-11-09
GUANGDONG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to overcome the shortcomings and deficiencies in the prior art, such as harsh preparation conditions, complicated preparation process, long time, inability to prepare in large quantities, and low fluorescence quantum yield of the product, The purpose of the present invention is to provide a quick and easy preparation method of lignin-based carbon quantum dots with high quantum yield; the method is to use carboxylated or aminated lignin and organic acid as carbon source; Lignin and organic acid microwave heating, dehydration, polymerization, carbonization, and doping with nitrogen-containing reagents to regulate surface defects, so as to obtain lignin carbon quantum dots with high quantum yield

Method used

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  • Rapid and simple preparation method of lignin-based carbon quantum dots with high quantum yield
  • Rapid and simple preparation method of lignin-based carbon quantum dots with high quantum yield
  • Rapid and simple preparation method of lignin-based carbon quantum dots with high quantum yield

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Embodiment 1

[0033]Dissolve 10g of Longli enzymatic lignin in an alkaline solution, add 6g of monochloroacetic acid dropwise, and heat at a constant temperature for 90 minutes. After the reaction, adjust the pH to acidic to precipitate the modified lignin, centrifugally wash, and dry for later use. Weigh 0.25 g of the obtained modified lignin and 10 g of citric acid, disperse them in 50 mL of ultrapure water under magnetic stirring, add 1.0 g of ethylenediamine, and disperse by ultrasonic oscillation for 15 min. After microwave reaction at 150° C. for 5 minutes, take it out, and naturally cool to room temperature, the crude product of lignin carbon quantum dots is obtained; the crude product is centrifuged, filtered through a filter membrane, and the filtrate is collected. After the filtrate was purified by dialysis with a 5000 Da specification dialysis bag, a lignin-based carbon quantum dot solution was obtained, and its quantum yield was measured to be 56.82%. The lignin-based carbon qua...

Embodiment 2

[0035] Dissolve 10g of bioleborin lignin in an alkaline solution, add 6g of sodium hypochlorite dropwise, and heat at a constant temperature for 90 minutes. After the reaction, adjust the pH to acidic to precipitate the modified lignin, centrifuge and wash, and dry for later use. Weigh 0.5 g of the obtained modified lignin and 10 g of citric acid, disperse them in 50 mL of ultrapure water under magnetic stirring, add 0.5 g of o-phenylenediamine, and disperse by ultrasonic oscillation for 5 min. Then microwave reaction at 150° C. for 20 minutes, take it out, and naturally cool to room temperature to obtain a crude product of lignin carbon quantum dots; centrifuge the crude product, filter it through a filter membrane, and collect the filtrate. After the filtrate was purified by dialysis with a 3000Da specification dialysis bag, a lignin-based carbon quantum dot solution was obtained, and the measured quantum yield was 64.49%. The lignin-based carbon quantum dot solution is rota...

Embodiment 3

[0037] Dissolve 10g of Shanghai Yunzhe alkali lignin in alkaline solution, add 6g of sodium bromide dropwise, and heat at a constant temperature for 90min. After the reaction, adjust the pH to acidic to precipitate the modified lignin, centrifuge and wash, and dry for later use. Weigh 0.5 g of the obtained modified lignin and 1.5 g of glycolic acid, disperse them in 20 mL of ultrapure water under magnetic stirring, add 1 g of urea, and disperse with ultrasonic oscillation for 20 min. Then microwave reaction at 200° C. for 30 minutes, take it out, and naturally cool to room temperature to obtain a crude product of lignin carbon quantum dots; centrifuge the crude product, filter it through a filter membrane, and collect the filtrate. After the filtrate was dialyzed and purified with a 500 Da specification dialysis bag, a lignin-based carbon quantum dot solution was obtained, and its quantum yield was measured to be 42.53%. The lignin-based carbon quantum dot solution is rotative...

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Abstract

The invention belongs to the field of fluorescent carbon quantum dot preparation, and discloses a rapid and simple preparation method of lignin-based carbon quantum dots with a high quantum yield. The method comprises the following steps: firstly, mixing a carbon source consisting of modified lignin and organic acid with a nitrogen source consisting of a nitrogen-containing reagent, adding the mixture into a solvent to obtain a mixed solution, then carrying out ultrasonic treatment on the mixed solution, and finally, carrying out microwave heating on the mixed solution for a period of time to obtain a nitrogen-containing carbon quantum dot mixed solution; and after the reaction is finished, centrifuging, filtering, dialyzing and freeze-drying the mixed solution to obtain carbon quantum dot powder. By adjusting the pH value, the surface groups are protonated or deprotonated, so that the fluorescent carbon quantum dots emitting blue light and green light are obtained. Nitrogen atom doping can stabilize the surface defects of the carbon quantum dots, improve the radiative transition probability and enhance the photoluminescence performance, so that the lignin-based carbon quantum dots with the relative quantum yield as high as 70.77% are obtained.

Description

technical field [0001] The invention belongs to the field of preparation of fluorescent carbon quantum dots, in particular to a method for preparing fast, simple and high quantum yield lignin-based carbon quantum dots. Background technique [0002] Carbon quantum dots are a new type of fluorescent nanoparticles with a size below 10nm. They belong to zero-dimensional carbon nanomaterials and have excellent photoluminescence properties. With its unique nanoscale structure, carbon quantum dots have many excellent properties different from traditional metal quantum dots, such as excellent chemical stability, good light stability and photobleaching resistance, excellent water solubility, low cytotoxicity, and biocompatibility. It has potential application value in biomedical fields such as bioimaging, drug delivery, and ion detection in vivo. Since Xu et al. accidentally produced carbon quantum dots in the experiment in 2004, the research on carbon quantum dots has developed rap...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/15C09K11/65B82Y20/00B82Y40/00
CPCC01B32/15C09K11/65B82Y20/00B82Y40/00
Inventor 秦延林徐少杰卢微邱学青林绪亮武卫东袁慢景
Owner GUANGDONG UNIV OF TECH
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