Blue fluorescent silica gel, preparation method and application

Abstract

The invention belongs to the technical field of chemical material synthesis, and particularly relates to blue fluorescent silica gel as well as a preparation method and application thereof. The blue fluorescent silica gel provided by the invention is specifically prepared by the following steps: firstly, dissolving citric acid in water, adding an amino silanization reagent into the water, and preparing silanization carbon quantum dots through a hydrothermal method reaction; and secondly, dispersing silica gel in ethanol, adding the prepared silanized carbon quantum dots, adding ammonia water, and modifying the silica gel with the carbon quantum dots to obtain the blue fluorescent silica gel. The preparation method has the beneficial effects that the preparation raw materials of the blue fluorescent silica gel provided by the invention are wide in source and low in cost, and the whole preparation process is simple to operate and is more suitable for large-scale production of the blue fluorescent silica gel.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical material synthesis, and particularly relates to blue fluorescent silica gel, a preparation method and application thereof. Background Art

[0002] Carbon quantum dots (CQDs) are a class of carbon nanomaterials with outstanding fluorescence properties. They are composed of quasi-discrete spherical carbon nanoparticles with a size of less than 10 nm. They have the characteristics of good water solubility, high biocompatibility and easy modification. However, CQDs are prone to agglomeration, which can lead to fluorescence quenching and greatly reduce their fluorescence performance.

[0003] Fluorescent silica gel porous materials have the characteristics of high porosity and outstanding fluorescence properties, and have broad application prospects in the fields of residual pesticides and metal ion detection.

[0004] In recent years, in order to improve the photostability and optoelectronic properties of CQDs, researchers have carried out various functional modifications through rational design, and introduced them into polymer matrices. In particular, CQDs are combined with silica gel materials to prepare CQD-modified fluorescent silica gel, which also possesses the characteristics of both components.

[0005] For example, patent CN112321833A forms a molecular imprinting material by grafting a molecular imprinting functional monomer with a fluorescent dye, combining the monomer with fluorescence, and hydrogen bonding the monomer with the template molecule. However, the versatility of this technology is poor, and the prepared fluorescent material is encapsulated in silica gel, which is not conducive to further modification.

[0006] In addition, patent CN 114106635A discloses a method for preparing a fluorescent silica gel material using biscarbazole aldehyde and melamine. However, the preparation process of the fluorescent silica gel material provided therein is extremely complicated and time-consuming.

[0007] In addition, the raw material cost of the preparation method of the fluorescent silica gel material provided in the above scheme is also relatively high, which results in a high ex-factory processing price of the industrialized product.

[0008] Therefore, it is extremely necessary to improve the preparation process of fluorescent silica gel materials, broaden the source of raw materials, simplify process operations, reduce manufacturing costs, and make the manufacture of fluorescent silica gel materials more suitable for large-scale production. Summary of the Invention

[0009] In order to solve the above technical problems, the present invention provides a blue fluorescent silica gel, a preparation method and an application.

[0010] The present invention provides a method for preparing blue fluorescent silica gel, comprising the following steps: Preparation of S1 Silylated Carbon Quantum Dots Dissolve citric acid in water, add an aminosilylating agent thereto, mix thoroughly, and prepare silanized carbon quantum dots by a hydrothermal reaction; Preparation of S2 blue fluorescent silica gel Silica gel was dispersed in ethanol, and the silanized carbon quantum dots prepared in S1 were added, and ammonia water was added at the same time to modify the silica gel with carbon quantum dots to obtain blue fluorescent silica gel.

[0011] In the preparation method of the above-mentioned blue fluorescent silica gel provided by the present invention, preferably, in S1, the aminosilanization agent is selected from any one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyl-trimethoxysilane or diethylenetriaminopropyl-trimethoxysilane.

[0012] More preferably, in S1, the aminosilylating agent is 3-aminopropyltriethoxysilane.

[0013] Preferably, in S1, the weight-to-volume ratio of citric acid to water is 1 g:3-50 mL, and the weight-to-volume ratio of citric acid to aminosilylating agent is 1-5 g:1 mL.

[0014] More preferably, in S1, the weight-to-volume ratio of citric acid to water is 1 g:8-15 mL, and the weight-to-volume ratio of citric acid to aminosilylating agent is 1-3 g:1 mL.

[0015] As further preferred, in S1, the weight-to-volume ratio of citric acid to water is 1 g:10 mL, and the weight-to-volume ratio of citric acid to aminosilylating agent is 2 g:1 mL.

[0016] Preferably, the temperature of the hydrothermal reaction in S1 is 155-200° C., and the reaction time is 5-20 h.

[0017] More preferably, the temperature of the hydrothermal reaction in S1 is 160-190° C., and the reaction time is 8-12 h.

[0018] As a further preference, the temperature of the hydrothermal reaction in S1 is 180° C., and the reaction time is 10 h.

[0019] Preferably, the mass fraction of the ammonia water described in S2 is 20% to 50%.

[0020] More preferably, the mass fraction of the ammonia water described in S2 is 20% to 30%.

[0021] As further preferred, the mass fraction of the ammonia water described in S2 is 25%.

[0022] Preferably, the weight-to-volume ratio of the silica gel to ethanol in S2 is 1 g: 20-30 mL, and the weight-to-volume ratio of the silica gel to the silanized carbon quantum dots prepared in S1 and ammonia water is 1 g: 2-5 mL: 2-8 mL.

[0023] More preferably, the weight-to-volume ratio of the silica gel to ethanol in S2 is 1 g: 20-25 mL, and the weight-to-volume ratio of the silica gel to the silanized carbon quantum dots prepared in S1 and ammonia water is 1 g: 2-3 mL: 2-4 mL.

[0024] Preferably, the particle size of the silica gel described in S2 is 200-300 mesh.

[0025] Furthermore, the present invention provides a method for preparing blue fluorescent silica gel, comprising the following steps: Preparation of S1 Silylated Carbon Quantum Dots Citric acid is dissolved in water, an aminosilylating agent is added thereto, the mixture is thoroughly mixed, and the mixture is reacted at 155-200°C for 5-20 h by a hydrothermal method to prepare silylated carbon quantum dots, wherein the weight-to-volume ratio of citric acid to water is 1 g:3-50 mL, and the weight-to-volume ratio of citric acid to aminosilylating agent is 1-5 g:1 mL; Preparation of S2 blue fluorescent silica gel Silica gel with a particle size of 200-300 mesh was dispersed in ethanol, and the silanized carbon quantum dots prepared in S1 were added. Ammonia water was also added to modify the silica gel with carbon quantum dots to obtain blue fluorescent silica gel. The weight-to-volume ratio of silica gel to ethanol was 1 g:20-30 mL, and the weight-to-volume ratio of silica gel to the silanized carbon quantum dots prepared in S1 and ammonia water was 1 g:2-5 mL:2-8 mL. The mass fraction of ammonia water was 20%-50%.

[0026] The blue fluorescent silica gel prepared by the above-mentioned preparation method and the application of the blue fluorescent silica gel are also the technical contents protected by the present invention. The application is specifically to use the blue fluorescent silica gel in the preparation of detection materials or identification materials.

[0027] The beneficial effects of the present invention are: (1) A method for preparing fluorescent silica gel material with a wide range of raw material sources, simple operation steps and low synthesis cost is provided, namely, firstly, aminosilylating agent and citric acid are reacted hydrothermally to generate silyl-modified carbon quantum dots, and then the carbon dots are modified onto the silica gel surface by a gel-sol reaction method to obtain a blue fluorescent silica gel material.

[0028] (2) The carbon quantum dots synthesized by the hydrothermal method in the present invention are non-toxic and harmless and have strong fluorescence. Compared with fluorescent dyes, the fluorescent silica gel synthesized after modification with carbon quantum dots has strong blue fluorescence and can be used in the preparation of synthetic inspection and detection materials or identification materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of the blue fluorescent silica gel provided by the present invention; Figure 2 TEM image of the silanized carbon quantum dots prepared in Example 1 of the present invention; Figure 3 This is an infrared absorption spectrum of the blue carbon quantum dot-modified silica gel and silica gel prepared in Example 1 of the present invention; Figure 4 This is a fluorescence image of the blue fluorescent silica gel prepared in Example 1 of the present invention under ultraviolet light. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the present invention, the present invention will be further explained in conjunction with specific embodiments.

[0031] Example 1 Preparation of S1 Silylated Carbon Quantum Dots Dissolve 2 g of citric acid in 20 mL of water, add 1 mL of 3-aminopropyltriethoxysilane, mix thoroughly, pour the mixed solution into a hydrothermal reactor, react at 180°C for 10 h, and after cooling, take out the product solution to obtain silanized carbon quantum dots; Preparation of S2 blue fluorescent silica gel Disperse 2 g of 200-300 mesh silica gel particles in 45 mL of anhydrous ethanol, add 5 mL of the silanized carbon quantum dot solution prepared in S1, and at the same time add 6 mL of 25% ammonia water. Place a magnetic bar and stir continuously for 10 h. Filter out the silica gel with filter paper and rinse with ethanol.

[0032] Attachment Figure 1 Schematic diagram of the structure of the blue fluorescent silica gel provided by the present invention; Figure 2 is a transmission electron microscope (TEM) image of the silanized carbon quantum dots prepared in step S1; Figure 3 This is the infrared absorption diagram of blue fluorescent silica gel modified with silica gel and blue carbon quantum dots; Figure 4 The fluorescence of carbon quantum dots under 365 nm ultraviolet light.

[0033] As can be seen from the above figures, after the blue quantum dots are modified on the non-fluorescent silica gel, it shows strong blue fluorescence under 365 nm ultraviolet light.

Claims

1. A method for preparing blue fluorescent silica gel, characterized in that: The following steps are involved: Preparation of S1 Silylated Carbon Quantum Dots Dissolve citric acid in water, add an aminosilylating agent thereto, mix thoroughly, and prepare silanized carbon quantum dots by a hydrothermal reaction; Preparation of S2 blue fluorescent silica gel Silica gel was dispersed in ethanol, and the silanized carbon quantum dots prepared in S1 were added, and ammonia water was added at the same time to modify the silica gel with carbon quantum dots to obtain blue fluorescent silica gel.

2. The method for preparing blue fluorescent silica gel according to claim 1, wherein: The aminosilylating agent described in S1 is selected from any one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyl-trimethoxysilane and diethylenetriaminopropyl-trimethoxysilane.

3. The method for preparing blue fluorescent silica gel according to claim 1, wherein: In S1, the weight-to-volume ratio of citric acid to water is 1 g: 3-50 mL, and the weight-to-volume ratio of citric acid to aminosilylating agent is 1-5 g: 1 mL.

4. The method for preparing blue fluorescent silica gel according to claim 1, wherein: The hydrothermal reaction temperature described in S1 is 155~200℃, and the reaction time is 5~20 h.

5. The method for preparing blue fluorescent silica gel according to claim 1, wherein: The mass fraction of the ammonia water described in S2 is 20% to 50%.

6. The method for preparing blue fluorescent silica gel according to claim 1, wherein: The weight-to-volume ratio of the silica gel to ethanol described in S2 is 1 g: 20-30 mL, and the weight-to-volume ratio of the silica gel to the silanized carbon quantum dots prepared in S1 and ammonia water is 1 g: 2-5 mL: 2-8 mL.

7. The method for preparing blue fluorescent silica gel according to claim 1, wherein: The particle size of the silica gel described in S2 is 200-300 mesh.

8. The method for preparing blue fluorescent silica gel according to claim 1, wherein: The following steps are involved: Preparation of S1 Silylated Carbon Quantum Dots Citric acid is dissolved in water, an aminosilylating agent is added thereto, the mixture is thoroughly mixed, and the mixture is reacted at 155-200°C for 5-20 h by a hydrothermal method to prepare silylated carbon quantum dots, wherein the weight-to-volume ratio of citric acid to water is 1 g:3-50 mL, and the weight-to-volume ratio of citric acid to aminosilylating agent is 1-5 g:1 mL; Preparation of S2 blue fluorescent silica gel Silica gel with a particle size of 200-300 mesh was dispersed in ethanol, and the silanized carbon quantum dots prepared in S1 were added. Ammonia water was also added to modify the silica gel with carbon quantum dots to obtain blue fluorescent silica gel. The weight-to-volume ratio of silica gel to ethanol was 1 g:20-30 mL, and the weight-to-volume ratio of silica gel to the silanized carbon quantum dots prepared in S1 and ammonia water was 1 g:2-5 mL:2-8 mL. The mass fraction of ammonia water was 20%-50%.

9. Application of the blue fluorescent silica gel prepared by the preparation method according to claim 1, characterized in that: The blue fluorescent silica gel is used in preparing detection materials or marking materials.

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