Preparation method of carbon quantum dots, and method for detecting dichromate ions by using carbon quantum dots

A carbon quantum dot and dichromate technology, which is applied in the field of carbon quantum dot preparation, can solve the problems of less detection, complicated methods, and complicated preparation of substances for detecting ions, and achieves low raw materials, uniform particle size distribution, and simple methods. quick effect

Active Publication Date: 2018-12-07
INST OF CHEM CHINESE ACAD OF SCI +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

for Cr 2 o 7 2- The detection of ions is rarely studied, and most of the methods are r

Method used

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  • Preparation method of carbon quantum dots, and method for detecting dichromate ions by using carbon quantum dots
  • Preparation method of carbon quantum dots, and method for detecting dichromate ions by using carbon quantum dots
  • Preparation method of carbon quantum dots, and method for detecting dichromate ions by using carbon quantum dots

Examples

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Embodiment 1

[0043] Use a pipette gun to add phosphoric acid into a 100ml beaker filled with deionized water to form an aqueous phosphoric acid solution, then add ethylenediamine to the above solution, and the molar ratio of phosphoric acid to ethylenediamine is 1:2. Stirring is then carried out at 80°C. A relatively violent reaction was carried out in an instant, and a large amount of white smoke was released during the reaction. Then, the beaker was placed on a magnetic stirrer, and the stirring was accelerated at 80°C to allow the reactants to fully react, and then transferred to a sealed polytetrafluoroethylene container. In the reaction kettle, put it into an oven and react under heating at 160°C for 8h. After cooling down to room temperature naturally, the obtained yellow-brown solution was passed through a 0.22 μM filter membrane, and the obtained filtrate was transferred to an ultrafiltration tube for centrifugation for 15 minutes to obtain the final clear solution in the tube. Th...

Embodiment 2

[0045] Use a pipette gun to add phosphoric acid to a 100ml beaker filled with deionized water to form a phosphoric acid aqueous solution, then use a pipette gun to add ethylenediamine to the above solution, the molar ratio of phosphoric acid to ethylenediamine is 1:4. Stirring is then carried out at 80°C. A relatively violent reaction was carried out in an instant, and a large amount of white smoke was released during the reaction. Then, the beaker was placed on a magnetic stirrer, and the stirring was accelerated at 80°C to allow the reactants to fully react, and then transferred to a sealed polytetrafluoroethylene container. In the reaction kettle, put it into an oven and react under heating at 140°C for 8h. After naturally cooling to room temperature, pass the obtained yellow-brown solution through a 0.22 μM filter membrane, transfer the obtained filtrate into an ultrafiltration tube and centrifuge for 30 min to obtain the final clear solution in the tube. The solution in ...

Embodiment 3

[0047] The present invention has also studied carbon quantum dots for different concentrations of Cr 2 o 7 2- detection situation.

[0048] (1) Adopt the carbon quantum dots of embodiment 1 to configure the carbon quantum dot solution, wherein the carbon quantum dot concentration is 0.3mg / ml.

[0049] (2) Configure Cr with a concentration of 0, 0.1, 0.2, 0.3, 0.5, 0.7, 1, 2, 3, 5, 7, 10, 15, 20, 25, 40, 50, 70, 90, 100, 120, 140, 160 μM 2 o 7 2- Solution, the above series of known concentrations of Cr 2 o 7 2- Solution is added in the carbon quantum dot solution that step (1) prepares, irradiates excitation light (excitation wavelength is 365nm), measures the change of its fluorescence intensity with Cr 2 o 7 2- Concentration variation (see figure 2 ), the results show that the fluorescence intensity increases with Cr 2 o 7 2- The concentration increases and decreases; according to the detected fluorescence intensity of the solution, the relationship between the...

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Abstract

The invention belongs to the technical field of applications of fluorescence carbon nano-materials, and concretely relates to a preparation method of carbon quantum dots, and a method for detecting dichromate ions by using the carbon quantum dots. The green preparation of the carbon quantum dots is carried out by using cheap and easily available phosphoric acid or water-soluble phosphate and organic amine as raw materials without a surface passivating agent or other additives in order to prepare the N,P-doped carbon quantum dots having a good water solubility, the carbon quantum dots have uniformly distributed particle sizes, and the average diameter of carbon quantum dot particles is not more than 5 nm. The preparation method has the advantages of cheap raw materials, simplicity and fastness, the selective detection of Cr<2>O<7><2-> is realized by the quantum dots, the detection limit of the quantum dots to Cr<2>O<7><2-> is low, the lowest detection limit can reach 1.2 [mu]M, and highly sensitive detection is achieved. The detection method is not affected by most interference ions (such as Cu<2+>, K<+>, Na<+>, Ca<2+>, Mg<2+>, Co<2+>, Ni<2+>, Ba<2+>, Pb<2+>, Fe<2+>, Zn<2+>, Al<3+>and Fe<3+>, and has a great application prospect.

Description

technical field [0001] The invention belongs to the technical field of application of fluorescent carbon nanometer materials, in particular to a method for preparing carbon quantum dots and a method for detecting dichromate with carbon quantum dots. Background technique [0002] At present, the wide application of compounds containing hexavalent chromium in the chemical industry has caused great harm to the environment and human health. Long-term exposure to large doses of hexavalent chromium can cause chromic skin ulcers, dermatitis and eczema, and cause damage to the respiratory tract, eyes and digestive tract. Therefore, quantitative detection of chromium ion concentration becomes particularly important. At present, the diphenylcarbazide spectrophotometric method is the standard method for determining hexavalent chromium ions, but due to the shortcomings of this method, such as detection limit difference, many interferences, complicated operation, time-consuming and labo...

Claims

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Application Information

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IPC IPC(8): G01N21/64B82Y30/00
CPCB82Y30/00G01N21/643
Inventor 王春儒武斌蒋礼
Owner INST OF CHEM CHINESE ACAD OF SCI
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