Preparation method of ZIF-8 material

Abstract

The invention discloses a preparation method of a ZIF-8 material. The invention discloses a method for preparing a ZIF-8 material, which is simple to operate, rapid, efficient, safe and environment-friendly at normal temperature and pressure. The method comprises the following specific steps: dissolving an imidazole ligand in a solvent, then dissolving a nitrogen-containing crystallization regulator in the solution, then dissolving a zinc salt in the same solvent, and mixing with the solution to obtain the ZIF-8 material. The crystallization regulator added in the invention can control the crystallization speed, regulate the particle size of the product and reduce the dosage of raw materials. The ZIF-8 material obtained by the synthesis method is complete in structure, regular in morphology, relatively uniform in particle size, high in crystallinity and large in specific surface area; meanwhile, the method also has the advantages of environment friendliness, simple process, safety in operation, low cost, high efficiency and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal organic frameworks, and in particular relates to a method for preparing a ZIF-8 material that is green, safe, efficient and has good benefits. Background Art

[0002] Metal organic frameworks (MOFs) are a class of crystalline porous organic-inorganic hybrid materials with a periodic network structure. They are formed by inorganic metal ions or metal clusters connected with organic ligands. MOFs are different from both inorganic porous materials and general organic complexes. They have the rigidity of inorganic materials and the flexibility of organic materials. In comparison, MOFs have the advantages of high specific surface area, adjustable pore structure, and chemical diversity. They have been widely studied in adsorption separation, catalysts, drug delivery, optical materials, gas energy storage, etc. There are many types of MOFs, which can be specifically divided into several major series such as IRMOFs, ZIFs, MILs, CPLs and PCNs.

[0003] Zeolitic imidazolate frameworks (ZIFs), a subclass of MOFs, are coordination polymers formed by tetracoordinated transition metals (such as Co and Zn) linked to imidazole ligands (such as 2-methylimidazole and benzimidazole). These polymers exhibit a zeolite-like structure. ZIFs combine the excellent properties of zeolites and metal-organic frameworks (MOFs) with exceptional chemical stability, attracting considerable research interest.

[0004] ZIF-8 is the most representative of ZIFs, with promising applications in catalysis, separation, and adsorption. Prepared from a divalent zinc salt and 2-methylimidazole, ZIF-8 is a white powder with a zeolite SOD topology that is stable in boiling water and alkaline solutions. Chen Xiaoming's group synthesized this material for the first time, and Yaghi's group systematically named it ZIF-8 and confirmed its excellent thermal and chemical stability.

[0005] ZIF-8 is considered one of the most promising MOFs materials for large-scale synthesis and even mass production. Its synthesis methods are diverse, with the most common methods being hydrothermal and solvothermal. Patent CN107611387A uses ZIF-8 as a precursor for the positive electrode material of a lead-carbon battery. It uses zinc nitrate hexahydrate as a zinc source and 2-methylimidazole as an organic ligand, synthesizing ZIF-8 in a methanol-based solvent atmosphere. Patent CN115536858B synthesizes ZIF-8 by dissolving hydrated zinc nitrate and 2-methylimidazole in a polar solvent, mixing, and stirring. Patent CN106883179A uses a solvothermal method to synthesize ZIF-8. First, zinc nitrate hexahydrate is dissolved in deionized water, and 2-methylimidazole is dissolved in DMF (i.e., N,N-dimethylformamide) solvent. Then, a certain amount of DMF or a mixture of DMF and water is heated as a base liquid. The zinc nitrate solution and 2-methylimidazole solution are added dropwise to the base liquid to obtain the ZIF-8 material. This method requires a continuous reaction at 80°C to 180°C for 8 to 28 hours, which faces greater cost and environmental pressures. Patent CN114133584B introduces a green, efficient, and uniform method for synthesizing ZIF-8 materials. Its main features are that the synthesis reaction uses 2-methylimidazole, resorcinol, and zinc salt as raw materials. Although water is used as the solvent, the solvent cost is low and environmentally friendly, but the reaction process requires the addition of up to 100g / L of resorcinol. At the same time, it also has high equipment requirements and requires continuous high-speed stirring of 800r / min to 1000r / min, which has become a limiting factor affecting its large-scale synthesis. Therefore, it is of great significance to develop a safe and efficient method for synthesizing ZIF-8 materials. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a green, safe, efficient and cost-effective method for preparing ZIF-8 material.

[0007] The present invention provides a method for preparing ZIF-8 materials at room temperature and pressure that is simple, rapid, efficient, safe, and environmentally friendly. The method comprises dissolving an imidazole ligand in a solvent, dissolving a nitrogen-containing crystallization modifier in the solvent, and dissolving a zinc salt in the same solvent before mixing the mixture with the solvent to produce the ZIF-8 material.

[0008] The preparation method of the aforementioned ZIF-8 material comprises the following steps:

[0009] (1) dissolving an imidazole ligand in a solvent to obtain a solution A;

[0010] (2) dissolving a nitrogen-containing alkaline accelerator in the above solution A to obtain solution B;

[0011] (3) dissolving the zinc salt in the same solvent as in step (1) to obtain solution C;

[0012] (4) Solution C is added to solution B to obtain ZIF-8 material.

[0013] Furthermore, step (1), step (2), step (3) and step (4) are carried out at normal temperature and pressure.

[0014] Furthermore, in step (1), the imidazole ligand refers to 2-methylimidazole;

[0015] Furthermore, in step (1) and step (3), the solvent refers to water, ethanol, methanol or a mixture of two or three of these solvents. If necessary, N-dimethylformamide, dimethyl sulfoxide or tetrahydrofuran can be added as a solubilizing agent.

[0016] Furthermore, in step (2), the crystallization modifier refers to a combination of any one or more of the following nitrogen-containing substances: n-hexylamine, cyclohexylamine, di-n-hexylamine, dicyclohexylamine, isooctylamine, 2-methylcyclohexylamine, 4-butylcyclohexylamine, 4-pentylcyclohexylamine, 4-methylcyclohexylamine, 4-sec-butylcyclohexylamine, 1-methylcyclohexylamine, 4-propylcyclohexylamine, 4-phenylcyclohexylamine, N-benzylcyclohexylamine, n-butylamine, tert-butylamine, sec-butylamine, isobutylamine, di-n-butylamine, tripentylamine, dipentylamine, isopentylamine, neopentylamine, n-pentylamine, cyclopentylamine, triisopentylamine, diisopentylamine, and cyclohexyl carbonate.

[0017] Furthermore, in step (3), the zinc salt refers to any one or more of zinc sulfate (or zinc sulfate heptahydrate), zinc chloride (or zinc chloride hexahydrate), zinc nitrate (or zinc nitrate hexahydrate), zinc acetate (or zinc acetate dihydrate), and zinc bromide (or zinc bromide dihydrate);

[0018] Furthermore, step (4) is carried out under ultrasound, stirring or shaking.

[0019] Compared with the prior art, the present invention has the following advantages or effects:

[0020] (1) The process of the present invention is simple, and the reaction only takes 1-2 hours at room temperature and pressure. During the material synthesis process, no heating equipment such as an oil bath is required, and no high-temperature and high-pressure resistant reactor equipment is required, thereby significantly reducing the equipment cost and operating cost during the material preparation process. The present invention has the advantages of low equipment requirements, low energy consumption, high synthesis speed and efficiency, and good reproducibility.

[0021] (2) The present invention adds a nitrogen-containing crystallization regulator, which can control the crystallization rate, regulate the product particle size, and reduce the amount of raw materials used. The nitrogen-containing crystallization regulator is a combination of any one or more of the following chemicals: n-hexylamine, cyclohexylamine, di-n-hexylamine, dicyclohexylamine, isooctylamine, 2-methylcyclohexylamine, 4-butylcyclohexylamine, 4-pentylcyclohexylamine, 4-methylcyclohexylamine, 4-sec-butylcyclohexylamine, 1-methylcyclohexylamine, 4-propylcyclohexylamine, 4-phenylcyclohexylamine, N-benzylcyclohexylamine, n-butylamine, tert-butylamine, sec-butylamine, isobutylamine, di-n-butylamine, tripentylamine, dipentylamine, isopentylamine, neopentylamine, n-pentylamine, cyclopentylamine, triisopentylamine, diisopentylamine, and cyclohexyl carbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the SEM image of the ZIF-8 material prepared in Example 1.

[0023] Figure 2 This is the SEM image of the ZIF-8 material prepared in Example 2.

[0024] Figure 3 This is the XRD pattern of the ZIF-8 material prepared in Example 1.

[0025] Figure 4 This is the BET test graph of the ZIF-8 material prepared in Example 1.

[0026] Figure 5 This is the BET test graph of the ZIF-8 material prepared in Example 2.

[0027] Figure 6 This is the pore size distribution diagram of the ZIF-8 material prepared in Example 1. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the implementation and protection scope of the present invention are not limited thereto.

[0029] Example 1

[0030] 12.39 g of 2-methylimidazole was dissolved in 250 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 9.5 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 7.37 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0031] pass Figure 1 It can be seen that the ZIF-8 material prepared by the process of Example 1 of the present invention has a relatively uniform particle size of 700 nm-1000 nm, and a rhombic dodecahedron structure with clear edges and corners.

[0032] pass Figure 3 It can be seen that the diffraction peak of the ZIF-8 material prepared by the process of Example 1 of the present invention is consistent with the diffraction peak of ZIF-8 reported in the literature, and the intensity of the diffraction peak is very high, indicating that the ZIF-8 material prepared by the present invention has high crystallinity.

[0033] pass Figure 4 It can be seen that the nitrogen adsorption-desorption curve of the ZIF-8 material prepared by the process of Example 1 of the present invention is a Type I isotherm, which is a typical microporous structure.

[0034] pass Figure 6 It can be seen that the average pore diameter of the ZIF-8 material prepared by the process of Example 1 of the present invention is about 1.3 nm, and it has a microporous structure.

[0035] Example 2

[0036] 9.64 g of 2-methylimidazole was dissolved in 200 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 12 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 7.37 g of zinc acetate dihydrate was added to 75 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0037] pass Figure 2 It can be seen that the ZIF-8 material prepared by the process of Example 1 of the present invention has a relatively uniform particle size of 700 nm to 900 nm, and a rhombic dodecahedron structure with clear edges and corners.

[0038] pass Figure 5 It can be seen that the nitrogen adsorption-desorption curve of the ZIF-8 material prepared by the process of Example 1 of the present invention is a Type I isotherm, which is a typical microporous structure.

[0039] Example 3

[0040] 9.64 g of 2-methylimidazole was dissolved in 250 ml of tap water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 8.0 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 7.37 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B under continuous stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0041] Example 4

[0042] 16.52 g of 2-methylimidazole was dissolved in 250 ml of tap water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 10.0 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 7.37 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0043] Example 5

[0044] 12.39 g of 2-methylimidazole was dissolved in 250 ml of tap water and stirred for 5 minutes to fully dissolve it to obtain solution A; 12.0 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it to obtain solution B; 7.37 g was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it to obtain solution C; solution C was completely poured into solution B under continuous stirring and continued to stir for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0045] Example 6

[0046] 49.5 g of 2-methylimidazole was dissolved in 900 ml of tap water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 50.0 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 29.5 g of zinc acetate dihydrate was added to 300 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B under continuous stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 8 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 12 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0047] Example 7

[0048] 2.21 g of 2-methylimidazole was dissolved in 50 ml of tap water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 2.5 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 10 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0049] Example 8

[0050] 2.48 g of 2-methylimidazole was dissolved in 50 ml of tap water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 3.0 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0051] Example 9

[0052] 12.39 g of 2-methylimidazole was dissolved in 250 ml of tap water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 9.5 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 7.37 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0053] Example 10

[0054] 9.64 g of 2-methylimidazole was dissolved in 200 ml of tap water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 12 mL of n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 7.37 g of zinc acetate dihydrate was added to 75 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0055] Example 11

[0056] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 2.0 mL of di-n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0057] Example 12

[0058] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 2.5 mL of di-n-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0059] Example 13

[0060] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 2.0 mL of isobutylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0061] Example 14

[0062] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 2.5 mL of tert-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0063] Example 15

[0064] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 2.5 mL of sec-butylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0065] Example 16

[0066] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 3.5 mL of n-hexylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0067] Example 17

[0068] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 4.0 mL of cyclohexylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0069] Example 18

[0070] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 1.0 g of cyclohexylamine carbonate was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0071] Example 19

[0072] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 3.5 ml of cyclopentylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0073] Example 20

[0074] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 3.0 ml of tripentylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0075] Example 21

[0076] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 3.0 ml of isoamylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0077] Example 22

[0078] 2.48 g of 2-methylimidazole was dissolved in 50 ml of deionized water and stirred for 5 minutes to fully dissolve it, obtaining solution A; 3.0 ml of n-pentylamine was added to solution A and stirred for 5 minutes to fully dissolve it, obtaining solution B; 1.48 g of zinc acetate dihydrate was added to 50 ml of tap water and stirred for 5 minutes to completely dissolve it, obtaining solution C; solution C was completely poured into solution B while continuously stirring, and stirring was continued for 2 hours. The resulting mixed solution was allowed to stand at room temperature and pressure for 4 hours to separate the layers and the sediment layer was taken; the sediment layer was centrifuged and washed, and dried at 100-150°C for 8 hours to obtain a white powdery solid, which was the target product ZIF-8.

[0079] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a ZIF-8 material, characterized in that: The preparation is carried out in the presence of a nitrogen-containing crystallization modifier. The specific method is as follows: (1) dissolving an imidazole ligand in a solvent to obtain a solution A; (2) dissolving a nitrogen-containing crystallization modifier in the above solution A to obtain solution B; (3) dissolving the zinc salt in the same solvent as in step (1) to obtain solution C; (4) Solution C is added to solution B to obtain ZIF-8 material.

2. The method for preparing a ZIF-8 material according to claim 1, wherein Step (1), step (2), step (3) and step (4) are carried out at room temperature and normal pressure.

3. A method for preparing a ZIF-8 material according to claim 1, characterized in that, The solvent is selected from one or more of water, ethanol and methanol.

4. A method for preparing a ZIF-8 material according to claim 1, characterized in that, The imidazole ligand is selected from 2-methylimidazole.

5. A method for preparing a ZIF-8 material according to claim 3, characterized in that, N-Dimethylformamide, dimethyl sulfoxide and tetrahydrofuran are added to the solvent as a solubilizing agent.

6. A method for preparing a ZIF-8 material according to claim 1, characterized in that, The zinc salt is selected from zinc sulfate, zinc sulfate heptahydrate, zinc chloride, zinc chloride hexahydrate, zinc nitrate, zinc acetate dihydrate, zinc acetate, zinc acetate dihydrate, zinc bromide or one or more of zinc bromide dihydrate.

7. A method for preparing a ZIF-8 material according to claim 1, characterized in that, The nitrogen-containing crystallization modifier refers to a combination of any one or more of the following nitrogen-containing substances: n-hexylamine, cyclohexylamine, di-n-hexylamine, dicyclohexylamine, isooctylamine, 2-methylcyclohexylamine, 4-butylcyclohexylamine, 4-pentylcyclohexylamine, 4-methylcyclohexylamine, 4-sec-butylcyclohexylamine, 1-methylcyclohexylamine, 4-propylcyclohexylamine, 4-phenylcyclohexylamine, N-benzylcyclohexylamine, n-butylamine, tert-butylamine, sec-butylamine, isobutylamine, di-n-butylamine, tripentylamine, dipentylamine, isopentylamine, neopentylamine, n-pentylamine, cyclopentylamine, triisopentylamine, diisopentylamine, and cyclohexylamine carbonate.

8. A method for preparing a ZIF-8 material according to claim 1, characterized in that, Step (1) and step (2) are carried out in a natural state, or by means of ultrasound, stirring or shaking to accelerate dissolution.

9. A method for preparing a ZIF-8 material according to claim 1, characterized in that, Step (4) is carried out under ultrasonic, stirring or shaking conditions.

10. The ZIF-8 material prepared by the preparation method according to any one of claims 1 to 9.

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