A metal-organic framework material Ni(pyip) and its preparation method and applications

Abstract

This invention discloses a metal-organic framework material Ni(pyip), its preparation method, and its applications, belonging to the field of gas adsorption and separation technology. The chemical formula of the metal-organic framework material is Ni(pyip), where pyip is 5-(pyridin-4-yl)-isophthalic acid. The preparation method includes the following steps: dispersing a nickel metal salt in a mixed solvent of N,N-dimethylformamide and deionized water to obtain a first mixed solution; adding 5-(pyridin-4-yl)-isophthalic acid to the first mixed solution, and adding concentrated acid; transferring the solution to a high-pressure reactor for solvothermal synthesis to obtain the nickel-based metal-organic framework material. The metal-organic framework material prepared by this invention exhibits a saturated adsorption capacity of 1126.78 mg / g for the atmospheric pollutant toluene, which is 3-4 times that of traditional industrial adsorbents, demonstrating high industrial application value.

Description

Technical Field

[0001] This invention relates to the field of gas adsorption and separation technology, and more specifically, to a metal-organic framework material Ni(pyip) and its preparation method and applications. Background Technology

[0002] Volatile organic compounds (VOCs) are among the major air pollutants emitted by industries such as petrochemicals, coating and printing, and pharmaceutical synthesis. Toluene, a typical aromatic hydrocarbon VOC, is toxic, flammable, and explosive, posing a serious threat to the ecological environment and human health. With increasingly stringent environmental regulations, the development of efficient and safe toluene adsorption and recovery technologies has become an urgent need.

[0003] Currently, the mainstream industrial technologies for toluene treatment include combustion, condensation, and adsorption. Among these, adsorption is widely used due to its simple operation, low cost, and ease of toluene resource recovery. Activated carbon and zeolite molecular sieves are the most common industrial adsorbents. However, activated carbon typically has a saturated adsorption capacity of only ~350 mg / g for toluene at room temperature and pressure, and poses a flammable safety hazard. Traditional zeolite molecular sieves (such as ZSM-5), limited by their pore size and ion exchange sites, generally have an adsorption capacity of less than 300 mg / g for toluene, making it difficult to meet the needs of deep treatment of high-concentration waste gases.

[0004] In recent years, metal-organic frameworks (MOFs) have been regarded as candidate materials for next-generation high-performance adsorbents due to their ultra-high specific surface area, designable pore structure, and tunable chemical functionality. However, most of the MOFs reported so far (such as HKUST-1 and ZIF-8) have performed poorly in toluene adsorption tests, with adsorption capacities often below 600 mg / g. Furthermore, some materials are prone to framework collapse or poor cycle stability due to pore blockage during adsorption-desorption cycles.

[0005] Therefore, developing a metal-organic framework adsorbent with a novel topology, high toluene adsorption capacity, and good cycling stability remains a pressing technical problem to be solved in this field. Summary of the Invention

[0006] Based on this, in order to solve one of the above-mentioned technical problems, the present invention provides a metal-organic framework material Ni(pyip), its preparation method, and its applications, the specific technical solution of which is as follows: A metal-organic framework material Ni(pyip), wherein the chemical formula of Ni(pyip) contains 5-(pyridin-4-yl)-isophthalic acid; The metal-organic framework material Ni(pyip) has a monoclinic crystal system with space group Cc and cell parameters a=15.8333 Å, b=15.3686 Å, c=18.9863 Å, α=γ=90°, β=100.794°.

[0007] In addition, the present invention also provides a method for preparing a metal-organic framework material Ni(pyip), the method comprising the following steps: S1. N,N-dimethylformamide and deionized water are mixed evenly to obtain a mixed solvent; a nickel metal salt is dispersed in the mixed solvent to obtain a first mixed solution; S2. Add 5-(pyridin-4-yl)-isophthalic acid to the first mixed solution, add concentrated acid, and stir thoroughly to obtain a second mixed solution; S3. The second mixed solution is transferred to a high-pressure reactor for solvothermal synthesis reaction. After the reaction is completed, a suspension is formed. The suspension is then subjected to solid-liquid separation, and the solid phase is washed multiple times with N,N-dimethylformamide. After drying, it is heated under vacuum to remove the solvent, thus obtaining the metal-organic framework material Ni(pyip).

[0008] Further, in step S1, the volume ratio of N,N-dimethylformamide to deionized water is (2~10):1; The mass-to-volume ratio of the nickel metal salt to the N,N-dimethylformamide is 5 mg: (2~5) mL.

[0009] Further, in step S1, the nickel metal salt is at least one of nickel chloride and nickel nitrate.

[0010] Furthermore, the molar ratio of the nickel metal salt to 5-(pyridin-4-yl)-isophthalic acid is (1~3):1.

[0011] Furthermore, in step S2, the concentrated acid is at least one of concentrated hydrochloric acid and concentrated nitric acid.

[0012] Furthermore, the mass-to-volume ratio of the nickel metal salt to the concentrated acid is 1 mg: (1~10) μL.

[0013] Furthermore, in step S3, the temperature of the thermal synthesis reaction is 90~180℃, and the time is 24~60 h.

[0014] Furthermore, in step S3, the heating activation temperature is 100~200℃, and the time is 3~12h.

[0015] In addition, the present invention also provides an application of the metal-organic framework material Ni(pyip), which is the application of the metal-organic framework material Ni(pyip) in the adsorption and treatment of air pollutants, wherein the air pollutant is toluene.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention prepares a metal-organic framework material, Ni(pyip), with a novel topological structure. In its monoclinic crystal system (space group Cc), nickel ions form a unique coordination mode with 5-(pyridin-4-yl)-isophthalic acid ligands within its crystalline channels. The channel surface is rich in aromatic rings and polar sites, enabling strong π-π stacking interactions and van der Waals forces with toluene molecules, thereby achieving efficient recognition and capture of aromatic hydrocarbon molecules. Furthermore, the raw materials of this invention are readily available, the operation is simple, the overall process is easy to operate, and it is readily scalable for production and industrial application.

[0017] 2. The Ni(pyip) material prepared in this invention exhibits a saturated adsorption capacity of up to 1126.78 mg / g for toluene at room temperature (298 K) and atmospheric pressure. Compared with traditional industrial adsorbents (such as activated carbon at ~350 mg / g and zeolite molecular sieves at <300 mg / g), the adsorption capacity of this material is increased by 3 to 4 times, significantly outperforming most reported metal-organic framework materials (typically below 600 mg / g), demonstrating extremely strong potential for industrial applications.

[0018] 3. The Ni(pyip) material prepared by this invention has a rigid framework structure and reversible adsorption-desorption behavior. The Ni(pyip) material is not prone to framework collapse or pore blockage during the adsorption of toluene, and has high adsorption efficiency and good recycling performance, which can meet the needs of long-term industrial operation.

[0019] 4. The Ni(pyip) material prepared by this invention has a significantly increased single-use adsorption capacity. Using this material can effectively reduce the packing volume and regeneration frequency of the adsorption tower, and reduce the energy consumption of the system. At the same time, the higher adsorption capacity is conducive to improving the solvent recovery rate of toluene, thereby significantly reducing the equipment investment and operating costs of volatile organic compound treatment, and has extremely high economic value and market promotion prospects. Attached Figure Description

[0020] The invention will be further understood from the following description taken in conjunction with the accompanying drawings. The components in the drawings are not necessarily drawn to scale, but rather the emphasis is on illustrating the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.

[0021] Figure 1 This is a schematic diagram (direction 1) of the metal-organic framework material Ni(pyip) prepared in Example 1 of the present invention. Figure 2 This is a schematic diagram (direction 2) of the metal-organic framework material Ni(pyip) prepared in Example 1 of the present invention. Figure 3 This is a schematic diagram comparing the single-crystal XRD and calculated simulation values ​​of the metal-organic framework material Ni(pyip) prepared in Example 1 of the present invention. Figure 4 The PXRD patterns of the metal-organic framework materials Ni(pyip) prepared in Examples 1-4 of this invention are shown below. Figure 5 The toluene adsorption isotherm of Ni(pyip), a metal-organic framework material prepared in Example 1 of this invention, at 298 K. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] In one embodiment of the present invention, a metal-organic framework material Ni(pyip) is provided, wherein the chemical formula of the metal-organic framework material Ni(pyip) is 5-(pyridin-4-yl)-isophthalic acid; The metal-organic framework material Ni(pyip) has a monoclinic crystal system with space group Cc and cell parameters a=15.8333 Å, b=15.3686 Å, c=18.9863 Å, α=γ=90°, β=100.794°.

[0025] In addition, the present invention also provides a method for preparing a metal-organic framework material Ni(pyip), the method comprising the following steps: S1. N,N-dimethylformamide and deionized water are mixed evenly to obtain a mixed solvent; a nickel metal salt is dispersed in the mixed solvent to obtain a first mixed solution; S2. Add 5-(pyridin-4-yl)-isophthalic acid to the first mixed solution, add concentrated acid, and stir thoroughly to obtain a second mixed solution; S3. The second mixed solution is transferred to a high-pressure reactor for solvothermal synthesis reaction. After the reaction is completed, a suspension is formed. The suspension is then subjected to solid-liquid separation, and the solid phase is washed multiple times with N,N-dimethylformamide. After drying, it is heated under vacuum to remove the solvent, thus obtaining the metal-organic framework material Ni(pyip).

[0026] In one embodiment, in step S1, the volume ratio of N,N-dimethylformamide to deionized water is (2~10):1; The mass-to-volume ratio of the nickel metal salt to the N,N-dimethylformamide is 5 mg: (2~5) mL.

[0027] In one embodiment, in step S1, the nickel metal salt is at least one of nickel chloride and nickel nitrate.

[0028] In one embodiment, the molar ratio of the nickel metal salt to 5-(pyridin-4-yl)-isophthalic acid is (1~3):1.

[0029] In one embodiment, in step S2, the concentrated acid is at least one of concentrated hydrochloric acid and concentrated nitric acid.

[0030] In one embodiment, the mass-to-volume ratio of the nickel metal salt to the concentrated acid is 1 mg:(1~10) μL.

[0031] In one embodiment, in step S3, the temperature of the thermal synthesis reaction is 90~180°C and the time is 24~60 h.

[0032] In one embodiment, in step S3, the temperature for heating activation is 100~200℃ and the time is 3~12h.

[0033] In addition, the present invention also provides an application of the metal-organic framework material Ni(pyip), which is the application of the metal-organic framework material Ni(pyip) in the adsorption and treatment of air pollutants, wherein the air pollutant is toluene.

[0034] In the above scheme, through process optimization, the metal-organic framework material possesses a novel topological structure, and its crystalline pore environment is specifically designed for the efficient capture of aromatic hydrocarbon molecules. The metal-organic framework material exhibits extremely high adsorption capacity for toluene at room temperature and pressure, with an adsorption capacity as high as 1126.78 mg / g, which is 3 to 4 times that of traditional industrial adsorbents such as activated carbon and zeolite. It has the advantages of high adsorption efficiency and good cycle stability. Furthermore, thanks to its ultra-high adsorption capacity, this material can significantly improve the solvent recovery rate of a single adsorption cycle, effectively reduce the volume of the adsorption tower, and lower the system's operating energy consumption, thereby significantly reducing the equipment investment and operating costs for industrial waste gas treatment, and possessing extremely high industrial application value.

[0035] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments.

[0036] Example 1: Mix 6 mL of N,N-dimethylformamide and 1 mL of deionized water thoroughly to obtain a mixed solvent; 10 mg of NiCl2 was dispersed in a mixed solvent to obtain the first mixed solution; 10 mg of 5-(pyridin-4-yl)-isophthalic acid was added to the first mixed solution, followed by 10 μL of concentrated hydrochloric acid. The mixture was stirred thoroughly to obtain the second mixed solution. The second mixed solution was transferred to a high-pressure reactor and reacted at 120°C for 48 h. After the reaction was completed, a suspension was formed. The suspension was filtered and the filter cake was washed with N,N-dimethylformamide. After drying, it was placed in a vacuum and heated to 150°C for 10 h to activate it, thus obtaining the metal-organic framework material Ni(pyip)-1.

[0037] Example 2: Mix 8 mL of N,N-dimethylformamide and 1 mL of deionized water thoroughly to obtain a mixed solvent; 15 mg of Ni(NO3)2 was dispersed in a mixed solvent to obtain the first mixed solution; Add 20 mg of 5-(pyridin-4-yl)-isophthalic acid to the first mixed solution, then add 100 μL of concentrated nitric acid and stir thoroughly to obtain the second mixed solution; The second mixed solution was transferred to a high-pressure reactor and reacted at 150°C for 24 h. After the reaction was completed, a suspension was formed. The suspension was filtered and the filter cake was washed with N,N-dimethylformamide. After drying, it was placed in a vacuum and heated to 150°C for 12 h to activate it, thus obtaining the metal-organic framework material Ni(pyip)-2.

[0038] Example 3: Mix 12 mL of N,N-dimethylformamide and 1 mL of deionized water thoroughly to obtain a mixed solvent; 20 mg of NiCl2 was dispersed in a mixed solvent to obtain the first mixed solution; Add 60 mg of 5-(pyridin-4-yl)-isophthalic acid to the first mixed solution, then add 150 μL of concentrated hydrochloric acid and stir thoroughly to obtain the second mixed solution; The second mixed solution was transferred to a high-pressure reactor and reacted at 150°C for 48 hours. After the reaction was completed, a suspension was formed. The suspension was filtered and the filter cake was washed with N,N-dimethylformamide. After drying, it was placed in a vacuum and heated to 150°C for 10 h to activate it, thus obtaining the metal-organic framework material Ni(pyip)-3.

[0039] Example 4: Mix 6 mL of N,N-dimethylformamide and 2 mL of deionized water thoroughly to obtain a mixed solvent; 15 mg of NiCl2 was dispersed in a mixed solvent to obtain the first mixed solution; Add 15 mg of 5-(pyridin-4-yl)-isophthalic acid to the first mixed solution, then add 100 μL of concentrated hydrochloric acid and stir thoroughly to obtain the second mixed solution; The second mixed solution was transferred to a high-pressure reactor and reacted at 150°C for 48 h. After the reaction was completed, a suspension was formed. The suspension was filtered and the filter cake was washed with N,N-dimethylformamide. After drying, it was placed in a vacuum and heated to 180°C for 12 h to activate it, thus obtaining the metal-organic framework material Ni(pyip)-4.

[0040] Test example: a. Single-crystal structure analysis of the metal-organic framework material Ni(pyip) prepared in this invention: The Ni(pyip)-1 prepared in Example 1 was subjected to diffraction data collected at 293 K using a single-crystal diffractometer (Rigaku XtaLabSynergy) with Cu-Ka rays as the incident light. The unit cell parameters were obtained using the least squares method, and the structure was analyzed and refined using the SHELXTL program. The crystallographic data of Ni(pyip)-1 are shown in Table 1 below. The results show that the composition of Example 1 is Ni(pyip). Examples 2-4 are the same as Example 1 and will not be described again here.

[0041] Table 1: Diffraction Data

[0042] Analysis of the data in Table 1 shows that the material prepared in this application has the composition of Ni (pyip), belongs to the monoclinic crystal system, has the space group Cc, and has the cell parameters a=15.8333 Å, b=15.3686 Å, c=18.9863 Å, α=γ=90°, and β=100.794°.

[0043] in addition, Figure 1-2 This is a coordination diagram of Ni(pyip)-1 prepared in Example 1 of this application. As can be seen from the figure, Ni in the MOF material Ni(pyip) of this application is coordinated with three oxygen atoms and one pyridine nitrogen atom in four 5-(pyridin-4-yl)-isophthalic acid.

[0044] b. X-ray powder diffraction (XRD) analysis of the metal-organic framework material Ni(pyip) prepared in this invention: The crystal structures of Ni(pyip)-1, Ni(pyip)-2, Ni(pyip)-3, and Ni(pyip)-4 prepared in Examples 1-4 of this invention were characterized using a German D8 ADVANCE X-ray powder diffractometer. The scanning range was 5-50° at twice the diffraction angle, with a scanning step size of 0.02°. The voltage and current used for the test were 40 kV and 40 mA, respectively, and CuK X-rays were used.

[0045] Figure 3 This paper compares the PXRD pattern of Ni(pyip)-1 prepared in Example 1 of this invention with the calculated simulation value. Based on single-crystal X-ray diffraction data, an optimized all-atom crystal structure model of the material was constructed using Materials Studio software. According to Bragg's diffraction law, its powder X-ray diffraction (PXRD) pattern was obtained through theoretical simulation. The simulated pattern was compared with the experimentally obtained PXRD pattern. The results show that the characteristic peak positions of the two are basically consistent, and the characteristic peak at the 8-10° position is highly consistent, indicating that the crystal structure of the material is consistent with the theoretical model obtained from single-crystal analysis.

[0046] Figure 4 The figures show the PXRD spectra of Ni(pyip)-1, Ni(pyip)-2, Ni(pyip)-3, and Ni(pyip)-4 prepared in Examples 1-4 of this invention. As can be seen from the figures, the PXRD diffraction peaks of the four Ni(pyip) samples prepared in Examples 1-4 are at the same positions, indicating that Ni(pyip) materials can be synthesized using the experimental conditions of Examples 1-4. Furthermore, the PXRD spectra of all four Ni(pyip) samples show narrow diffraction peaks and strong peak intensities, indicating that these four samples all possess high crystallinity and high phase purity.

[0047] c. Toluene adsorption performance of the metal-organic framework material Ni(pyip) prepared in Example 1 of this invention: The toluene adsorption performance of Ni(pyip) prepared in Example 1 of this invention was tested using a Bestech BSD-VVS multi-station gravimetric vapor adsorption analyzer at 298 K. The adsorption capacity showed a continuous increasing trend with increasing relative pressure (P / P0), exhibiting distinct segmented characteristics: in the low relative pressure region (P / P0 < 0.4), the slow increase in adsorption was mainly attributed to micropore filling and monolayer adsorption; while in the high relative pressure region (P / P0 > 0.4), the adsorption increased significantly, corresponding to capillary condensation within the mesopores or multilayer adsorption on the outer surface. Notably, no obvious saturation plateau was observed across the entire tested pressure range, indicating that the material possesses a large pore volume or flexible pore structure. Its toluene adsorption capacity near saturated vapor pressure ultimately reached approximately 1126.78 mg / g, which is 3-4 times that of conventional toluene adsorbents.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A metal-organic framework material Ni(pyip), characterized in that, The chemical formula of the metal-organic framework material Ni(pyip) is 5-(pyridin-4-yl)-isophthalic acid; The metal-organic framework material Ni(pyip) has a monoclinic crystal system with space group Cc and cell parameters a=15.8333 Å, b=15.3686 Å, c=18.9863 Å, α=γ=90°, β=100.794°.

2. A method for preparing a metal-organic framework material Ni(pyip), characterized in that, The preparation method is used to prepare the metal-organic framework material Ni(pyip) as described in claim 1, and the preparation method includes the following steps: S1. N,N-dimethylformamide and deionized water are mixed evenly to obtain a mixed solvent; a nickel metal salt is dispersed in the mixed solvent to obtain a first mixed solution; S2. Add 5-(pyridin-4-yl)-isophthalic acid to the first mixed solution, add concentrated acid, and stir thoroughly to obtain a second mixed solution; S3. The second mixed solution is transferred to a high-pressure reactor for solvothermal synthesis reaction. After the reaction is completed, a suspension is formed. The suspension is then subjected to solid-liquid separation, and the solid phase is washed multiple times with N,N-dimethylformamide. After drying, it is heated under vacuum to remove the solvent, thus obtaining the metal-organic framework material Ni(pyip).

3. The preparation method according to claim 2, characterized in that, In step S1, the volume ratio of N,N-dimethylformamide to deionized water is (2~10):1; The mass-to-volume ratio of the nickel metal salt to the N,N-dimethylformamide is 5 mg: (2~5) mL.

4. The preparation method according to claim 2, characterized in that, In step S1, the nickel metal salt is at least one of nickel chloride and nickel nitrate.

5. The preparation method according to claim 2, characterized in that, The molar ratio of the nickel metal salt to 5-(pyridin-4-yl)-isophthalic acid is (1~3):

1.

6. The preparation method according to claim 2, characterized in that, In step S2, the concentrated acid is at least one of concentrated hydrochloric acid and concentrated nitric acid.

7. The preparation method according to claim 2, characterized in that, The mass-to-volume ratio of the nickel metal salt to the concentrated acid is 1 mg: (1~10) μL.

8. The preparation method according to claim 2, characterized in that, In step S3, the temperature of the thermal synthesis reaction is 90~180℃ and the time is 24~60 h.

9. The preparation method according to claim 2, characterized in that, In step S3, the heating activation temperature is 100~200℃ and the time is 3~12h.

10. An application of a metal-organic framework material Ni(pyip), characterized in that, The application refers to the application of the metal-organic framework material Ni(pyip) prepared by the preparation method according to any one of claims 1 or 2 to 9 in the adsorption and treatment of air pollutants, wherein the air pollutant is toluene.

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