Novel Bi-MOF material and preparation method and application thereof

Abstract

The invention belongs to the field of preparation of metal organic frameworks (MOFs) materials, and particularly discloses a novel Bi-MOF material and a preparation method and application thereof.The preparation method comprises the following steps that bismuth nitrate pentahydrate powder and 2, 4, 6-triiodobenzene-1, 3, 5-tricarboxylic acid are ultrasonically dispersed in N, N-dimethylformamide, and a mixed solution is obtained; and carrying out solvothermal reaction on the mixed solution, separating, washing and drying to obtain Bi-MOF crystal particles. The halogen atom iodine is innovatively introduced into the structure of the obtained novel Bi-MOF material, the electronic structure is changed, and iodide ions can be rapidly recognized through the iodine-iodine halogen bond action. Due to the properties, the SWUST-1 has a good application prospect in the fields of rapid identification, real-time detection, adsorption, photocatalysis and biomedicine of trace radioactive iodine.

Description

Technical Field

[0001] The present invention relates to the field of preparation of metal organic frameworks (MOFs) materials, and in particular to a novel Bi-MOF material and a preparation method and application thereof. Background Art

[0002] Metal-organic frameworks (MOFs) are a type of porous material composed of metal ions and organic ligands. They have a highly ordered structure and excellent properties such as large specific surface area, high porosity, and adjustable structure and function. Among them, bismuth-based metal-organic frameworks (Bi-MOFs) are composed of Bi 3+ Bismuth, one of the least toxic heavy metals, is linked to organic ligands. Bismuth possesses both hexa- and octa-coordinate structures, potentially creating unique pore structures and active sites. Bi-MOFs are therefore non-toxic, environmentally friendly, and thermally and chemically stable, offering broad application prospects in adsorption separation, catalysis, energy storage, and environmental remediation. However, the reported variety of Bi-MOFs is relatively limited, and some exhibit drawbacks, such as poor ion recognition and insufficient Lewis acidity.

[0003] The introduction of halogen atoms can significantly improve the performance of Bi-MOFs in terms of electronic structure, surface properties, and coordination environment. The introduction of halogen atoms will reduce the band gap. This is because the halogen orbitals can hybridize with the bismuth orbitals to form a new valence band. The strong spin-orbit coupling effect of the halogen atoms may cause band splitting, and the lone electron pairs of the halogens and the empty orbitals of bismuth can form charge transfer channels. In terms of ion recognition, the electron-withdrawing effect of the halogens can enhance the Lewis acidity of Bi-MOFs. At the same time, the halogen atoms will form halogen bonds with ions (such as iodide ions), thereby improving the recognition ability of ions. However, the introduction of halogen atoms into the Bi-MOF structure has rarely been reported. Summary of the Invention

[0004] To solve the above problems, the present invention provides a new Bi-MOF material and its preparation method and application.

[0005] The technical solutions of the present invention are as follows:

[0006] A new Bi-MOF material is provided. The halogen atom iodine is introduced into the structure of the new Bi-MOF material. The raw materials for preparing the new Bi-MOF material include bismuth nitrate pentahydrate, 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid, and N,N-dimethylformamide.

[0007] The present invention also provides a method for preparing the novel Bi-MOF material, the technical solution of which is as follows:

[0008] A method for preparing a novel Bi-MOF material comprises the following steps:

[0009] S1. Grinding bismuth nitrate pentahydrate solid powder;

[0010] S2. Ultrasonic dispersion of the bismuth nitrate pentahydrate powder and 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid in N,N-dimethylformamide to obtain a mixed solution;

[0011] S3. Subjecting the mixed solution to a solvothermal reaction, and obtaining novel Bi-MOF crystal particles after separation, washing, and drying.

[0012] In a further technical solution, in step S2, the molar ratio of the bismuth nitrate pentahydrate to 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid is:

[0013] Bismuth nitrate pentahydrate: 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid = 1:2-1:5.

[0014] In a further technical solution, in step S3, the solvent thermal reaction specifically includes the following steps:

[0015] The mixed solution in step S2 is placed in a polytetrafluoroethylene-lined reactor and heated in an oven at 110° C.-130° C. for 60 h-75 h.

[0016] In a further technical solution, in step S3, the washing method specifically includes the following steps:

[0017] The mixture was washed with N,N-dimethylformamide, and the light yellow solid particles at the lower layer were separated after natural precipitation and washed, and the washing was repeated three times.

[0018] In a further technical solution, in step S3, the drying method specifically includes the following steps:

[0019] Use a vacuum drying oven to dry at 50°C-65°C for 2h-4h to obtain a new Bi-MOF material.

[0020] The present invention also provides the use of the novel Bi-MOF material in identifying iodide ions.

[0021] The beneficial effects of the present invention are:

[0022] 1. This invention focuses on the synthesis strategy and performance optimization of Bi-MOFs, and proposes a novel Bi-MOF material and its preparation method based on a solvothermal method. By introducing the innovative strategy of halogen atom iodine into the Bi-MOF structure, the performance of Bi-MOFs is significantly improved from the perspectives of electronic structure, surface properties, and coordination environment, providing an important theoretical basis and technical support for the optimized design of Bi-MOFs. The novel Bi-MOF material of the present invention has a simple synthesis process and can be prepared within a wide range of raw material molar ratios, which facilitates the adjustment of the molar ratio according to actual needs in further applications, thereby controlling costs.

[0023] 2. The novel Bi-MOF material of the present invention can be successfully applied to the rapid identification and response of trace iodine ions, and can respond to iodine ions as low as 50 mM within 10 minutes. This MOF material is expected to show excellent performance in the field of rapid trace identification of radioactive iodine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The synthetic route for preparing SWUST-1 in Example 1 is shown below;

[0025] Figure 2 Scanning electron micrograph of SWUST-1 prepared in Example 1 and elemental mapping of Bi, I, and O;

[0026] Figure 3 This is the total element distribution spectrum of SWUST-1 prepared in Example 1;

[0027] Figure 4 This is the single crystal analytical structure diagram of SWUST-1 prepared in Example 1;

[0028] Figure 5 This is the X-ray diffraction pattern of SWUST-1 prepared in Example 1;

[0029] Figure 6 The X-ray diffraction patterns of SWUST-1 prepared by different raw material ratios in Example 2;

[0030] Figure 7 Dark-field optical microscopy time series images of SWUST-1 interacting with different concentrations of iodine ions in Example 3. Scale bar: 15 μm.

[0031] Figure 8 This is the X-ray diffraction pattern of SWUST-1 after reacting with iodide ions in Example 3. DETAILED DESCRIPTION

[0032] In order to make the contents of the present invention easier to understand, the technical solutions of the present invention are further explained clearly and completely below in conjunction with specific implementation methods.

[0033] This embodiment provides a new Bi-MOF material, in which the halogen atom iodine is introduced into the structure of the new Bi-MOF material. The raw materials for its preparation include bismuth nitrate pentahydrate, 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid, and N,N-dimethylformamide. The new Bi-MOF material is named SWUST-1.

[0034] Example 1:

[0035] A method for preparing SWUST-1 based on a solvothermal reaction, specifically comprising the following steps:

[0036] (1) Using an agate mortar, grind bismuth nitrate pentahydrate solid to a fine powder. Weigh 0.0243 g of the ground bismuth nitrate pentahydrate powder and 0.1352 g of 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid and place them in a 20 mL glass bottle.

[0037] (2) Add 10 mL of N,N-dimethylformamide to the glass bottle of step (1) above, and sonicate in an ultrasonic instrument until the solid is completely dissolved;

[0038] (3) Transfer the solution from step (2) above to a 50 mL polytetrafluoroethylene-lined reactor and heat in a 120°C oven for 72 h;

[0039] (4) After the reaction is completed, the reaction mixture is cooled naturally, and after standing, the yellowish solid particles at the bottom layer are removed and washed with N,N-dimethylformamide. This process is repeated three times.

[0040] (5) The light yellow solid particles obtained in the above step (4) were dried in a vacuum drying oven at 60° C. for 3 h to obtain SWUST-1 crystal particles.

[0041] In this embodiment, the synthetic route for preparing SWUST-1 is as follows: Figure 1 As shown, SWUST-1 crystal particles can be synthesized according to this route.

[0042] In this example, the scanning electron microscopy image of SWUST-1 prepared and the distribution of Bi, I, and O elements are shown in FIG. Figure 2 As shown, Bi, I, and O elements are evenly distributed in the particles.

[0043] In this example, the total element distribution spectrum of SWUST-1 prepared is as follows: Figure 3 shown.

[0044] In this embodiment, the single crystal structure of SWUST-1 prepared is shown in FIG. Figure 4 shown.

[0045] In this example, the X-ray diffraction pattern of the prepared SWUST-1 is as follows: Figure 5 As shown in Figure 3, the XRD patterns of the experimentally prepared SWUST-1 particles are well matched with those of the analyzed single crystal structure simulation.

[0046] Example 2:

[0047] Compared with Example 1, this embodiment has a different molar ratio of bismuth nitrate pentahydrate to 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid, and specifically includes the following steps:

[0048] (1) Using an agate mortar, grind bismuth nitrate pentahydrate solid to a fine powder state, and weigh five portions (0.0243 g) of bismuth nitrate pentahydrate powder and place them in five 20 mL glass bottles respectively;

[0049] (2) Weigh five portions of 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid powder, with masses of 0.0588 g, 0.0882 g, 0.1176 g, 0.1352 g, and 0.1470 g, respectively (the molar ratios of bismuth nitrate pentahydrate to 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid are 1:2, 1:3, 1:4, 1:4.6, and 1:5, respectively), and add them to the five glass bottles prepared in step (1) above, respectively;

[0050] (3) Add 10 mL of N,N-dimethylformamide to each of the five glass bottles prepared in step (2) above, and sonicate in an ultrasonicator until the solid is completely dissolved;

[0051] (4) Take five portions of the solution in step (3) and transfer them into five 50 mL polytetrafluoroethylene-lined reactors, and heat them in a 120°C oven for 72 h.

[0052] (5) After the reaction is completed, the reaction mixture is cooled naturally, and after standing, the yellowish solid particles at the bottom layer are taken out and washed with N,N-dimethylformamide, and the process is repeated three times.

[0053] (6) The five portions of SWUST-1 obtained in the above steps were dried in a vacuum drying oven at 60° C. for 3 h to obtain SWUST-1 crystal particles.

[0054] In this embodiment, the X-ray diffraction patterns of SWUST-1 prepared by different raw material ratios are as follows: Figure 6 shown.

[0055] Example 3:

[0056] The application of a novel Bi-MOF material in identifying iodide ions specifically includes the following steps:

[0057] (1) A small amount of SWUST-1 particles prepared in Example 1 was placed in a 2 mL centrifuge tube and ultrasonically dispersed using deionized water;

[0058] (2) Weigh 0.1499 g of sodium iodide and place it in a brown glass bottle. Use a pipette to add 1 mL of deionized water and sonicate until completely dissolved to obtain a 1000 mM iodide ion solution. Gradually dilute the 1000 mM iodide ion solution to obtain iodide ion solutions with concentrations of 100 mM, 50 mM, 10 mM, and 5 mM, respectively.

[0059] (3) Use a pipette to take 10 μL of the solution in step (1) above and drop it on the center of the slide, then cover it with a coverslip and observe it under a dark-field optical microscope;

[0060] (4) Use a pipette to take 10 μL of the iodide ion solution in step (2) above and drop it on the edge of the coverslip, allowing the liquid to enter along the edge of the coverslip, and observe and capture the image of the real-time changes of the particles.

[0061] The SWUST-1 of the present invention can be used to quickly identify iodide ions, and the color change of SWUST-1 particles during the identification process is observed by single-particle in-situ dynamic real-time imaging using dark-field optical microscopy technology.

[0062] The present invention performs X-ray diffraction characterization on SWUST-1 after reaction with iodide ions, which specifically includes the following steps:

[0063] (1) 0.0240 g of SWUST-1 particles prepared according to the method described in Example 1 were placed in a 2 mL centrifuge tube, 1 mL of 5 mM sodium iodide solution was added, shaken, reacted for 1 minute, and then allowed to stand.

[0064] (2) The lower precipitate in step (1) was washed twice with deionized water; the precipitate was then dried in a vacuum drying oven at 60° C. for 3 h to obtain SWUST-1 particles after reaction with iodine ions, which were characterized by X-ray diffractometer.

[0065] The principle of iodide ion recognition is that iodine in the SWUST-1 structure can form a halogen bond with iodide ions, and SWUST-1 reacts with iodide ions to form amorphous BiOI. X-ray diffraction patterns confirm the formation of amorphous BiOI after the reaction of SWUST-1 with iodide ions.

[0066] In this example, dark field optical microscopy time series images of SWUST-1 interacting with iodine ions at different concentrations are shown in FIG. Figure 7 shown.

[0067] In this embodiment, the X-ray diffraction pattern of SWUST-1 after reaction with iodine ions is as follows: Figure 8 shown.

[0068] The above-described embodiments merely represent specific implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A new Bi-MOF material, characterized in that: The halogen atom iodine is introduced into the structure of this new Bi-MOF material, and its preparation raw materials include bismuth nitrate pentahydrate, 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid, and N,N-dimethylformamide.

2. A method for preparing a novel Bi-MOF material, characterized in that: The following steps are involved: S1. Grinding bismuth nitrate pentahydrate solid powder; S2. Ultrasonic dispersion of the bismuth nitrate pentahydrate powder and 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid in N,N-dimethylformamide to obtain a mixed solution; S3. Subjecting the mixed solution to a solvothermal reaction, and obtaining novel Bi-MOF crystal particles after separation, washing, and drying.

3. The method for preparing the novel Bi-MOF material according to claim 2, characterized in that: In step S2, the molar ratio of bismuth nitrate pentahydrate to 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid is: Bismuth nitrate pentahydrate: 2,4,6-triiodobenzene-1,3,5-tricarboxylic acid = 1:2-1:

5.

4. The method for preparing the novel Bi-MOF material according to claim 2, characterized in that: In step S3, the solvent thermal reaction specifically includes the following steps: The mixed solution in step S2 is placed in a polytetrafluoroethylene-lined reactor and heated in an oven at 110° C.-130° C. for 60 h-75 h.

5. The method for preparing the novel Bi-MOF material according to claim 2, characterized in that: In step S3, the washing method specifically includes the following steps: The mixture was washed with N,N-dimethylformamide, and the light yellow solid particles at the lower layer were separated after natural precipitation and washed, and the washing was repeated three times.

6. The method for preparing the novel Bi-MOF material according to claim 2, characterized in that: In step S3, the drying method specifically includes the following steps: Use a vacuum drying oven to dry at 50°C-65°C for 2h-4h to obtain a new Bi-MOF material.

7. Use of the novel Bi-MOF material according to claim 1 in identifying iodide ions.

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