Method for extracting carbon quantum dots from activated carbon

A technology for carbon quantum dots and activated carbon, which is applied in the field of extracting carbon quantum dots, can solve the problems of low yield, expensive instruments, complicated processes, etc., and achieves the effects of uniform particle size, easy purification, and simple preparation process.

Active Publication Date: 2011-02-16
FUZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these methods have more or less disadvantages, such as expensive equipment, complicated process, low yield, difficult separation, etc.

Method used

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  • Method for extracting carbon quantum dots from activated carbon
  • Method for extracting carbon quantum dots from activated carbon
  • Method for extracting carbon quantum dots from activated carbon

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Add 1 g of dry activated carbon powder to 100 ml of 4 mol L -1 Reflux in nitric acid for 24 h. After naturally cooling to room temperature, take out the suspension and evaporate the resulting suspension to dryness by distillation under reduced pressure. The black solid (about 1.105 g) obtained by evaporation to dryness was dispersed in water and washed with 0.5 mol L -1 Neutralize with NaOH solution, and then centrifuge at 4000 rpm for 15 min to remove non-fluorescent precipitates. Collect the supernatant, and use four ultrafiltration centrifuge tubes with different molecular weight cut-offs of 3 kDa, 5 kDa, 10 kDa, and 30 kDa for step-by-step centrifugation. Five products with molecular weights 30 KDa were obtained by ultrafiltration and centrifugation, except for the product of >30 KDa, the other products showed good fluorescence activity. By weighing the mass of non-fluorescent active components, it can be estimated that the yield of carbon quantum dots is about 30...

Embodiment 2

[0028] Add 50 g of dry activated carbon powder to 100 ml of 12 mol L -1 Reflux in nitric acid for 30 h. After cooling down to room temperature naturally, take out the suspension and evaporate the resulting suspension to dryness by distillation under reduced pressure. Disperse the black solid obtained by evaporating to dryness with 0.5 mol L -1 Neutralize with NaOH solution, and then centrifuge at 4000 rpm for 30 min to remove non-fluorescent precipitates. The supernatant was collected, centrifuged with an ultrafiltration centrifuge tube with a molecular weight cut-off of 30 kDa, and the filtrate was collected and dried at 80°C to obtain <30 kDa carbon quantum dots.

Embodiment 3

[0030] Add 25 g of dry activated carbon powder to 100 ml of 8 mol L -1 Reflux in nitric acid for 30 h. After cooling down to room temperature naturally, take out the suspension and evaporate the resulting suspension to dryness by distillation under reduced pressure. Disperse the black solid obtained by evaporating to dryness with 0.5 mol L -1 Neutralize with NaOH solution, and then centrifuge at 4000 rpm for 30 min to remove non-fluorescent precipitates. The supernatant was collected, centrifuged with an ultrafiltration centrifuge tube with a molecular weight cut-off of 10 kDa, and the filtrate was collected and dried at 100°C to obtain <10 kDa carbon quantum dots.

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Abstract

The invention provides a method for extracting carbon quantum dots from activated carbon, which comprises the following steps of: adding dry activated carbon powder to salpeter solution and stirring for backflow; performing reduced pressure distillation for evaporating suspension obtained by backflow to dryness; dispersing obtained black solids in water, and neutralizing obtained solution with sodium hydroxide; and finally, centrifugating neutralized black suspension for removing precipitation, separating supernatant fluid by using an ultrafiltration centrifugal tube or an ultrafiltration membrane, collecting filtrate, and drying the filtrate to obtain carbon quantum dots. The method uses cheap and available activated carbon as carbon sources, and can obtain a large number of carbon quantum dots by simple chemical oxidation process and simple subsequent processes of evaporation, saturation, centrifugation and ultrafiltration. The carbon quantum dots are graphite structure nanocrystals with the grain diameter of 3 to 5 nm, the surfaces of which have a large amount of hydroxide radicals. The carbon quantum dots have good fluorescence and electrochemiluminescence.

Description

technical field [0001] The invention relates to a method for extracting carbon quantum dots from activated carbon. Background technique [0002] Luminescent nanoparticles have important application value in optoelectronic devices, biomarkers and biomedicine. Semiconductor quantum dots such as CdS, CdSe, CdTe, CdSe / ZnSe, PbS, Si, etc. have the advantages of controllable size, narrow emission wavelength range and high luminous quantum yield, but due to their poor water solubility, chemical Poor stability and most of them have strong toxicity and other shortcomings, which greatly restrict their application, especially in the field of biomedicine. [0003] Compared with the above-mentioned common semiconductor quantum dots, carbon quantum dots have many advantages, such as good chemical stability, biocompatibility and low toxicity, etc., thus gaining more and more attention. However, as an emerging nanomaterial, the preparation method of carbon dots is still rare. The methods...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K11/65C01B31/02B82B3/00
Inventor 池毓务董永强陈国南
Owner FUZHOU UNIV
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