Preparation method and application of novel europium-based metal organic framework film

Abstract

The invention discloses a preparation method and application of a novel europium-based metal organic framework film, and belongs to the field of new materials and sensors. According to the novel metal organic framework film, FTO glass is used as a cathode and an electroplating carrier, and a graphite rod is used as an anode; according to the preparation method, a mixed solution of 3, 3 ', 4, 4'-benzophenone tetracarboxylic dianhydride and europium nitrate is used as an electroplating solution, a novel europium-based metal organic framework with a film structure is rapidly generated on the surface of an FTO glass carrier through an electro-deposition method, and the preparation process is low in energy consumption, less in pollution and easy and safe to operate; the novel europium-based metal organic framework film has a red luminescence property and can specifically identify CO3 < 2->; the prepared europium-based metal organic framework is directly deposited on FTO glass, aggregation of the metal organic framework is effectively inhibited, active sites are fully exposed, the detection speed and selectivity are improved, and the europium-based metal organic framework has extremely important application value in the fields of environment monitoring, food detection and water quality analysis.

Description

Technical Field

[0001] The invention relates to the field of metal organic framework materials and fluorescence sensing technology, and in particular to a novel europium-based metal organic framework film preparation method and application thereof. Background Art

[0002] Carbonate ions are one of the commonly used ions in analytical chemistry. Their detection is of great significance in the fields of environmental monitoring, food testing, and water quality analysis. For example, the detection of carbonate ions in beverages and alcoholic beverages can evaluate their acidity and alkalinity and bubble content; the detection of carbonate ions in the environment can evaluate the carbon cycle process in the atmosphere, soil, and water bodies; the detection of carbonate ions in water bodies is conducive to the detection of the acidity and alkalinity of water bodies and the balance of carbon dioxide in the atmosphere.

[0003] At present, the main method for detecting carbonate is ion chromatography, which is cumbersome to operate and requires professional testing with high technical requirements and relatively high cost. Fluorescence spectroscopy has the advantages of simple operation, fast analysis speed and low price. Metal organic framework compounds (MOFs) are a type of organic-inorganic hybrid materials with certain pore sizes and surface areas that have been developed in recent years. The ever-changing organic and inorganic components enable MOFs to form a variety of topological structures. Due to the particularity of its structure, it has received widespread attention in the field of fluorescence detection technology in recent years. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art, and to provide a novel method for preparing a europium-based metal organic framework film and its application, which belongs to the field of new materials and sensors; the novel metal organic framework film uses FTO glass as a cathode and an electroplating carrier, a graphite rod as an anode, and a mixed solution of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and europium nitrate as an electroplating solution, and a novel europium-based metal organic framework with a thin film structure is quickly generated on the surface of the FTO glass carrier by an electrodeposition method, and the preparation process has low energy consumption, less pollution, simple and safe operation; the novel europium-based metal organic framework film has red luminescence performance and can specifically identify CO3 2- The prepared europium-based metal-organic framework is directly deposited on FTO glass, which effectively inhibits the aggregation of the metal-organic framework, fully exposes the active sites, improves the detection speed and selectivity, and has extremely important application value in the fields of environmental monitoring, food testing and water quality analysis.

[0005] In order to achieve the above technical effects, the following technical solutions are adopted:

[0006] A novel method for preparing a europium-based metal organic framework film comprises the following steps:

[0007] Using FTO conductive glass as the cathode, a graphite rod as the anode, and a mixed solution of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and europium nitrate hexahydrate as the electroplating solution, the novel europium-based metal-organic framework thin film is prepared by electrodeposition.

[0008] Furthermore, the size of the FTO conductive glass is 15 - 30 mm * 8 - 15 mm * 1.5 - 3.0 mm, and the resistance is 4 - 9 Ω; before use, it is ultrasonically cleaned with absolute ethanol and deionized water for 5 - 15 min respectively.

[0009] Furthermore, the diameter of the graphite rod is 4 - 8 mm. Furthermore, the solvent of the mixed solution of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and europium nitrate is N,N-dimethylformamide.

[0010] Furthermore, the concentration of 3,3',4,4'-benzophenone tetracarboxylic dianhydride in the mixed solution is 4.8 g / L - 8 g / L; the concentration of europium nitrate hexahydrate in the mixed solution is 0.675 g / L - 1.125 g / L.

[0011] Furthermore, the electrodeposition method is carried out using a DC regulated power supply.

[0012] Furthermore, the electrodeposition voltage is 4 V - 8 V, and the deposition time is 20 - 40 min.

[0013] A novel europium-based metal-organic framework thin film is prepared by using any one of the above preparation methods.

[0014] The application of the above-prepared novel europium-based metal-organic framework thin film in detecting carbonate ions.

[0015] The application of the above novel europium-based metal-organic framework thin film in detecting carbonate ions in the fields of environmental monitoring, food detection, and water quality analysis.

[0016] For example: the determination of the carbonate ion content in actual tap water samples.

[0017] The novel europium-based metal-organic framework material prepared by using the above preparation scheme has application value in the fields of environmental monitoring, food detection, and water quality analysis.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. In the present invention, with europium ions as the coordination center and 3,3',4,4'-benzophenone tetracarboxylic dianhydride as the ligand, through the electron transfer between the coordination center and the ligand, the fluorescence emission wavelength can reach 657 nm. This novel europium-based metal-organic framework thin film has red luminescence properties and can specifically recognize CO3 2- ; it can realize the detection of carbonate ions under infrared non-destructive conditions;

[0020] 2. The europium-based metal-organic framework prepared by the present invention is directly deposited on FTO, effectively inhibiting the aggregation of the metal-organic framework, fully exposing the active sites, and improving the detection speed and selectivity.

[0021] 3. Compared with the existing detection technologies, the synthesis method of the europium-based metal-organic framework in the present invention is simple and fast. The synthesis steps in the present invention have low energy consumption, short time consumption, less pollution, simple and safe operation; and it has extremely important application value in the fields of environmental monitoring, food detection, and water quality analysis. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0023] Figure 1 It is a process schematic diagram of the europium-based metal-organic framework material prepared in the embodiment of the present application;

[0024] Figure 2 It is an X-ray diffraction spectrum diagram of the europium-based metal-organic framework material powder prepared in Example 1 of the present application;

[0025] Figure 3 It is a scanning electron microscope image of the europium-based metal-organic framework material prepared in Example 1 of the present application;

[0026] Figure 4 It is a Fourier transform infrared spectrum diagram of the europium-based metal-organic framework material prepared in Example 1 of the present application;

[0027] Figure 5 It is an ultraviolet-visible absorption spectrum diagram of the europium-based metal-organic framework material prepared in Example 1 of the present application;

[0028] Figure 6 It is a practical image of the europium-based metal-organic framework material prepared in Example 1 of the present application under different light conditions;

[0029] Figure 7 It is a fluorescence absorption and emission spectrum diagram of the europium-based metal-organic framework material prepared in Example 1 of the present application in air and aqueous solution;

[0030] Figure 8 It is a fluorescence relative intensity comparison diagram of the europium-based metal-organic framework material prepared in Example 1 of the present application for detecting mixed ions. Detailed Embodiments

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0034] Example 1:

[0035] According to Figure 1 As shown in the schematic diagram of the process for preparing the europium-based metal-organic framework material, the preparation of the europium-based metal-organic framework material in the example is completed.

[0036] A method for preparing a europium-based metal-organic framework thin film material comprises the following steps:

[0037] Example 1:

[0038] (1) Dissolve 48 mg of 3,3’,4,4’-benzophenone tetracarboxylic dianhydride (HBPTC) and 6.75 mg of europium nitrate hexahydrate in 10 mL of DMF; place the obtained mixed solution in an ultrasonic cleaner and ultrasonicate for 10 min to obtain an electroplating solution;

[0039] (2) Ultrasonicate a 15 mm * 8 mm * 1.5 mm FTO glass successively with 10 mL of ethanol and deionized water for 5 min to remove the oxides and contaminants on the surface, and the resistance is 4 Ω;

[0040] (3) Place the electrode holding the FTO glass into the electroplating solution for the electrodeposition process of Eu-HBPTC. Use a graphite rod as the anode and the FTO glass as the cathode, and use a DC regulated power supply dual-electrode cell. Set the electroplating conditions as a constant voltage of 4 V and an electroplating time of 20 min. After electroplating is completed, take out the FTO glass, rinse the film with distilled water, and dry it in the air for standby.

[0041] Example 2:

[0042] (1) Dissolve 64 mg of 3,3’,4,4’-benzophenone tetracarboxylic dianhydride (HBPTC) and 9 mg of europium nitrate hexahydrate in 10 mL of DMF; place the resulting mixed solution in an ultrasonic cleaner and ultrasonicate for 30 min to obtain an electroplating solution;

[0043] (2) Ultrasonicate a 30 mm * 15 mm * 2.2 mm FTO glass successively with 10 mL of ethanol and deionized water for 10 min to remove surface oxides and contaminants, and its resistance is 7 Ω;

[0044] (3) Place the electrode holding the FTO glass into the electroplating solution to carry out the electrodeposition process of Eu-HBPTC. Use a graphite rod as the anode and the FTO glass as the cathode, and use a DC regulated power supply bipolar cell. Set the electroplating conditions as a constant voltage of 6 V and an electroplating time of 30 min. After electroplating is completed, take out the FTO glass, rinse the film with distilled water, and dry it in air for standby.

[0045] Example 3:

[0046] A preparation method of an europium-based metal-organic framework thin film material is as follows:

[0047] (1) Dissolve 80 mg of 3,3’,4,4’-benzophenone tetracarboxylic dianhydride (HBPTC) and 11.25 mg of europium nitrate hexahydrate in 10 mL of DMF. Place the resulting mixed solution in an ultrasonic cleaner and ultrasonicate for 30 min to obtain an electroplating solution.

[0048] (2) Ultrasonicate a 30 mm * 15 mm * 3.0 mm FTO glass successively with 10 mL of ethanol and deionized water for 10 min to remove surface oxides and contaminants; its resistance is 9 Ω;

[0049] (3) Place the electrode holding the FTO glass into the electroplating solution to carry out the electrodeposition process of Eu-HBPTC. Use a graphite rod as the anode and the FTO glass as the cathode, and use a DC regulated power supply bipolar cell. Set the electroplating conditions as a constant voltage of 8 V and an electroplating time of 40 min. After electroplating is completed, take out the FTO glass, rinse the film with distilled water, and dry it in air for standby.

[0050] Evaluate and characterize the europium-based metal-organic framework thin film material prepared in Example 2:

[0051] Figure 2 It is the X-ray diffraction pattern of the europium-based metal-organic framework material powder prepared in Example 2. The peak near 7° in the diffraction peak is the characteristic diffraction peak of Eu-HBPTC, and the diffraction peaks at 27.5° and 37.5° are the characteristic peaks of the FTO glass, indicating the success of preparing the Eu-HBPTC metal-organic framework thin film by the electrodeposition method.

[0052] Figure 3 Scanning electron microscopy image of the europium-based metal-organic framework material prepared in Example 2. As can be seen from Figure a, the morphology of the directly electrodeposited thin film is uniform. Under high-magnification scanning electron microscopy, it can be seen that the microtopography is similar to a porous quasi-spherical structure, which is conducive to the exposure of active sites, thereby enhancing the reaction activity.

[0053] Figure 4 Fourier transform infrared spectroscopy diagram of the europium-based metal-organic framework material prepared in Example 2. The absorption peaks located near 3400 cm -1 , 1620 cm -1 and 1410 cm -1 belong to the stretching vibration absorption peak of -OH, and the symmetric and asymmetric stretching vibration absorption peaks of C=O respectively. The peak shapes and positions of the ligand HBPTC and Eu-MOF are similar, indicating that the metal ion Eu 3+ only coordinates with the oxygen on the carbonyl bond in the ligand Eu 3+ , without causing a change in the C=O bond of the ligand functional group. At the same time, it can also be seen that the corresponding infrared absorption peaks of the two substances have shifted, indicating that Eu 3+ has successfully coordinated with HBPTC.

[0054] Figure 5 Ultraviolet-visible absorption spectroscopy diagram of the europium-based metal-organic framework material prepared in Example 2. It can be found from the figure that the Eu-HBPTC thin film has a relatively broad absorption peak at wavelengths of 290 - 320 nm.

[0055] Figure 6 Images of the europium-based metal-organic framework material prepared in Example 2 under different lighting conditions. The obvious color change characteristics of the Eu-MOF thin film from bright colorless to red under natural light and irradiation with a 254 nm to 365 nm portable ultraviolet lamp lay a material foundation for further developing it into a sensor with optical sensing performance.

[0056] Figure 7 Fluorescence absorption and emission spectra of the europium-based metal-organic framework material prepared in Example 2 in air and aqueous solution. As can be seen from the figure, when the excitation wavelength is 317 nm, the emission wavelengths of the Eu-HBPTC thin film in air are 593 nm, 617 nm, and 657 nm respectively; when the excitation wavelength is 317 nm, the emission wavelengths of the Eu-HBPTC thin film in water are 593 nm, 617 nm, and 650 nm respectively; the fluorescence intensity in water is slightly weaker than that in air, and the maximum emission wavelength blue-shifts from 657 nm in air to 650 nm. It can be seen that the Eu-HBPTC thin film can also emit strong fluorescence in water, which lays an experimental foundation for further salt solution testing.

[0057] Figure 8Fluorescence relative intensity diagram of the europium-based metal-organic framework material prepared in Example 2 for detecting mixed ions. Solutions of 1.0×10 -3 mol / L of KCl, KBr, KI, KClO4, KBrO3, Na2SO4, K2HPO4, Na3PO4, and K2CO3 were respectively prepared. The Eu-HBPTC thin film was immersed in the above solutions respectively, and at an excitation wavelength of 317 nm, the fluorescence intensity at an emission wavelength of 650 nm was recorded. From Figure 8 It can be seen that the Eu-HBPTC thin film still has good fluorescence characteristics in the solutions of KCl, KBr, KI, KClO4, KBrO3, Na2SO4, K2HPO4, and Na3PO4. The fluorescence intensity significantly decreases in the K2CO3 solution, indicating that carbonate solutions have a quenching effect on the fluorescence of Eu-HBPTC. It also shows that the Eu-HBPTC thin film has a high selectivity for carbonate solutions, and a fluorescence sensor with specific recognition of carbonate solutions can be developed based on this feature.

[0058] In summary, the present invention discloses a preparation method and application of a novel europium-based metal-organic framework thin film, belonging to the fields of new materials and sensors; this novel metal-organic framework thin film uses an FTO glass as the cathode and electroplating carrier, a graphite rod as the anode, and a mixed solution of 3,3’,4,4’-benzophenone tetracarboxylic dianhydride and europium nitrate as the electroplating solution. Through the electrodeposition method, a novel europium-based metal-organic framework with a thin film structure is rapidly formed on the surface of the FTO glass carrier. The preparation process has low energy consumption, less pollution, simple and safe operation; this novel europium-based metal-organic framework thin film has red luminescence properties and can specifically recognize CO3 2- ; the prepared europium-based metal-organic framework is directly deposited on the FTO glass, effectively inhibiting the aggregation of the metal-organic framework, fully exposing the active sites, improving the detection speed and selectivity, and having extremely important application value in the fields of environmental monitoring, food detection, and water quality analysis.

[0059] At this point, those skilled in the art recognize that although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and determined to cover all these other variations or modifications.

Claims

1. A preparation method of a novel europium-based metal-organic framework thin film, characterized in that, The preparation method comprises the following steps: Using the FTO conductive glass as the cathode, the graphite rod as the anode, and the mixed solution of 3,3’,4,4’-benzophenone tetracarboxylic dianhydride and europium nitrate hexahydrate as the electroplating solution, a novel europium-based metal-organic framework thin film is prepared by electrodeposition.

2. The preparation method of a novel europium-based metal-organic framework thin film as described in claim 1, characterized in that, The size of the FTO conductive glass is 15-30mm*10-20mm*1-2.2mm, and the resistance is 4-9Ω; before use, it is ultrasonically cleaned with absolute ethanol and deionized water for 5-15min respectively.

3. The preparation method of a novel europium-based metal-organic framework thin film as described in claim 1, characterized in that, The diameter of the graphite rod is 4-8mm.

4. The preparation method of a novel europium-based metal-organic framework thin film as described in claim 1, characterized in that, The solvent of the mixed solution of 3,3’,4,4’-benzophenone tetracarboxylic dianhydride and europium nitrate is N,N-dimethylformamide.

5. The preparation method of a novel europium-based metal-organic framework thin film as described in claim 1, characterized in that, The concentration of 3,3’,4,4’-benzophenone tetracarboxylic dianhydride in the mixed solution is 4.8g / L to 8g / L; the concentration of europium nitrate hexahydrate in the mixed solution is 0.675g / L to 1.125g / L.

6. The preparation method of a novel europium-based metal-organic framework thin film as described in claim 1, characterized in that, The electrodeposition method is carried out using a DC regulated power supply.

7. The preparation method of a novel europium-based metal-organic framework thin film as described in claim 1, characterized in that, The electrodeposition voltage is 4V to 8V, and the deposition time is 20 to 40min.

8. A novel europium-based metal-organic framework thin film, characterized in that, Prepared by the preparation method of any one of claims 1-7.

9. The application method of a novel europium-based metal-organic framework thin film as described in claim 8, characterized in that, The application of the novel europium-based metal-organic framework thin film in detecting carbonate ions.

10. The application method as described in claim 9, characterized in that, The application of the novel europium-based metal-organic framework thin film in detecting carbonate ions in the fields of environmental monitoring, food detection, and water quality analysis.

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