Preparation method and application of Ni-NH2-MOF-coated HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen

Abstract

The invention discloses a preparation method and application of a Ni-NH2-MOF-coated HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen, and belongs to the field of gas separation. The method comprises the following steps: 1, preparing HPP-COF powder; 2, preparing Ni-NH2-MOF (Metal Organic Framework) powder; and 3, compounding. According to the invention, Ni-NH2-MOF and HPP-COF are introduced into the field of gas adsorption, and a method for combining COF and MOF materials is creatively provided by utilizing the interaction of specific recognition of a perfluorinated compound and an amino group and a polymerization reinforcing structure on the surface of HPP-COF; a PFCs / N2 mixed gas separator meeting actual production requirements is prepared, the high adsorption capacity of MOF and the high stability of COF are combined, the problems that a traditional static porous material is poor in selectivity, stability and acid resistance are solved, specific adsorption of MOF to PFCs is enhanced, and selectivity is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of gas separation, and particularly relates to a preparation method and application of a Ni-NH2-MOF@HPP-COF composite material for adsorptive separation of perfluorocarbon gas / nitrogen. BACKGROUND

[0002] Gas insulated switchgear (GIS) is a kind of compact electrical equipment, and the operation reliability of GIS is crucial for the safe and stable operation of a power system. SF6 is widely used in GIS switch cabinets due to its excellent arc extinguishing and insulating properties, but partial discharge and other faults may occur in the gas insulated equipment during long-term operation, causing the decomposition of SF6 to produce perfluorocarbon gases (PFCs) such as carbon tetrafluoride (CF4), hexafluoroethene (C2F6) and perfluoropropane (C3F8), which further leads to a decrease in the insulating properties. On the other hand, PFCs have a huge greenhouse effect and a very high global warming potential (GWP): the GWP of CF4 is 7,380 times that of CO2, the GWP of C2F6 is 12,200 times that of CO2, and the GWP of C3F8 is 8,830 times that of CO2. They have a very long atmospheric lifetime (CF4 is about 50,000 years, C2F6 is about 10,000 years, and C3F8 is about 2,600 years), and once emitted, they will continue to accumulate in the atmosphere, causing irreversible long-term climate warming effects, and they also pose a threat to the health and safety of maintenance personnel. In recent years, in the field of adsorption of insulating gases, metal oxide adsorbent materials have been used to adsorb reaction products and moisture present in electrical equipment, and certain effects have been achieved, but there is a lack of efficient separation means for CF4, C2F6 and C3F8.

[0003] Current mainstream PFCs / N2 separation technologies such as low-temperature distillation, catalytic decomposition and membrane separation have the defects of high energy consumption, complex operation or high equipment cost. In contrast, adsorption separation technology based on porous adsorbents is concerned due to its simple operation and high energy efficiency ratio, but traditional adsorbents (such as zeolite and activated carbon) are limited by disordered pore structure and surface chemical inertness, which show low PFCs adsorption capacity, poor selectivity and insufficient regeneration efficiency in actual working conditions, and are difficult to meet the industrial separation requirements. The crystal porous materials metal organic framework (MOF) and covalent organic framework (COF) materials provide a new direction for breaking through the above bottleneck due to their customizable crystal structure, high specific surface area and precisely controllable pore characteristics. By changing the types of organic ligands, different pore sizes and surface chemical properties can be adjusted. However, the existing crystal porous material adsorbents still face two challenges: (1) the adsorption capacity and selectivity of traditional static porous materials are mutually restricted, and it is difficult to ensure high selectivity under large adsorption capacity; (2) the pores of most static porous materials cannot dynamically adapt to the complex working condition requirements of PFCs / N2 mixed gas separation, and in the actual operation process, the materials are often exposed to acidic environment, which makes the geometric spatial structure of the materials change easily in multiple adsorption-regeneration cycles, resulting in continuous attenuation of adsorption capacity and selectivity. SUMMARY

[0004] In order to solve the above technical problems, the application provides a preparation method and application of a Ni-NH2-MOF@HPP-COF composite material for adsorptive separation of perfluorocarbon gas / nitrogen.

[0005] The application introduces Ni-NH2-MOF and HPP-COF into the field of gas adsorption, utilizes the specific recognition interaction between perfluorocarbon gas (PFCs) and amino group, and the surface polymerization reinforcement structure of HPP-COF, and creatively proposes a method combining COF and MOF materials to prepare a PFCs / N2 mixed gas separation material that meets the actual production requirements, combines the high adsorption capacity of MOF with the strong stability of COF, and solves the problems of poor selectivity, poor stability and poor acid resistance of traditional static porous materials.

[0006] A preparation method of a Ni-NH2-MOF@HPP-COF composite material for adsorptive separation of perfluorocarbon gas / nitrogen, specifically completed according to the following steps:

[0007] I. Preparation of HPP-COF powder:

[0008] ①, dissolve 1,4-benzene diboronic acid in an ice bath 1,4-dioxane to obtain solution A;

[0009] ②, 2, 3, 6, 7, 10, 11-hexahydroxytriphenyl is dissolved in preheated trimethylbenzene to obtain solution B;

[0010] ③, solution A and solution B are mixed uniformly, and glacial acetic acid is added, mixed uniformly, to obtain solution C;

[0011] ④, solution C is transferred to the reaction kettle, and is reacted at 120 DEG C for 4-6 days to obtain a reaction product; the reaction product is immersed in methanol for activation, and finally vacuum dried to obtain HPP-COF powder;

[0012] Second, the preparation of Ni-NH2-MOF powder:

[0013] Ni (NO3) 2.6H2O and 3-amino isonicotinic acid are dissolved in N, N-dimethylformamide to obtain solution D; solution D is reacted at 160 DEG C for 2-3 days to obtain a reaction product; the reaction product is immersed in N, N-dimethylformamide for activation, and then vacuum dried to obtain Ni-NH2-MOF powder;

[0014] Third, the preparation of Ni-NH2-MOF@HPP-COF composite material:

[0015] ①, the Ni-NH2-MOF powder is dissolved in N, N-dimethylformamide, and ultrasonic treated for a period of time to obtain a Ni-NH2-MOF solution;

[0016] ②, the HPP-COF powder is dissolved in methanol, and ultrasonic treated for a period of time to obtain a HPP-COF solution;

[0017] ③, under the condition of stirring, the HPP-COF solution is added to the Ni-NH2-MOF solution, and then glacial acetic acid is added, and stirring is continued for a period of time to obtain solution E;

[0018] ④, solution E is transferred to the reaction kettle, and is reacted at 80 DEG C for 18h-30h to obtain a reaction product; the reaction product is immersed in N, N-dimethylformamide and methanol for alternating activation for 2-3 days, and the alternating solvent activation is carried out every 3h-5h, and finally vacuum dried to obtain the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen.

[0019] The Ni-NH2-MOF@HPP-COF composite material is used for adsorbing and separating perfluorocarbon gas and nitrogen; the perfluorocarbon gas is CF4, C2F6 or C3F8.

[0020] The principle of the application:

[0021] HPP-COF is an organic framework with -NH- as covalent bond synthesized by nucleophilic aromatic substitution reaction. Compared with the imine bond (-C=N-) in some COFs which is easy to be hydrolyzed, -NH- bond has higher bond energy and stronger chemical inertness, and is not easy to be attacked by H + (acidic conditions) or OH - (alkaline conditions), so its stability in acid and alkali environment is significantly improved. HPP-COF is covalently polymerized on Ni-NH2-MOF by in-situ growth method to improve the structural stability and acid resistance of the MOF, so that the structure of the MOF can remain stable in multiple adsorption-regeneration cycles.

[0022] Meanwhile, the ligand functional group NH2 on the Ni-NH2-MOF not only serves as the positioning site for HPP in-situ growth, but also enhances the specific recognition ability of the MOF to PFCs, greatly improving the selectivity of the material to PFCs.

[0023] The beneficial effects of the present application are:

[0024] The brittle skeleton of traditional crystalline porous materials is prone to structural collapse or active site deactivation in multiple adsorption-regeneration cycles under acidic conditions, resulting in continuous attenuation of adsorption capacity and selectivity. The present application improves the mechanical stability and acid resistance of the MOF by coordinating assembly and surface polymerization of HPP-COF on Ni-NH2-MOF, ensuring the structural stability of the material in multiple adsorption cycles in practical applications. At the same time, the amino group enhances the specific adsorption of the MOF to PFCs through weak hydrogen bonding and polar-induced dipole interaction, improving the selectivity. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Adsorption capacity of CF4 of the Ni-NH2-MOF@HPP-COF composite material prepared in Example 1 and Examples 6-9;

[0026] Figure 2 Adsorption capacity of CF4 of the Ni-NH2-MOF@HPP-COF composite material prepared in Examples 1-5;

[0027] Figure 3 Characterization chart of cycle desorption-adsorption selectivity and cycle desorption-adsorption capacity of CF4 of the Ni-NH2-MOF@HPP-COF composite material prepared in Example 1. DETAILED DESCRIPTION

[0028] The following drugs were all purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (analytical grade, 99% purity): 1,4-phenylenediboric acid (165.74), 2,3,6,7,10,11-hexahydroxytriphenylene (324.28), dioxane, mesitylene, acetic acid, N,N-dimethylformamide, methanol, nickel nitrate hexahydrate (Ni(NO3)2·6H2O), and 3-aminoisonicotinic acid.

[0029] Specific Implementation Method 1: This implementation method is a preparation method of Ni-NH2-MOF@HPP-COF composite material for adsorption and separation of perfluorinated carbon gas / nitrogen, specifically completed according to the following steps:

[0030] I. Preparation of HPP-COF powder:

[0031] ① Dissolve 1,4-phenyldiboronic acid in an ice bath containing 1,4-dioxane to obtain solution A;

[0032] ② Dissolve 2,3,6,7,10,11-hexahydroxytriphenylene in preheated trimethylbenzene to obtain solution B;

[0033] ③ Mix solution A and solution B thoroughly, then add glacial acetic acid and mix thoroughly to obtain solution C;

[0034] ④ Transfer solution C to a reaction vessel and react at 120℃ for 4 to 6 days to obtain the reaction product; immerse the reaction product in methanol for activation, and finally vacuum dry to obtain HPP-COF powder;

[0035] II. Preparation of Ni-NH2-MOF powder:

[0036] Ni(NO3)2·6H2O and 3-aminoisonicotinic acid were dissolved in N,N-dimethylformamide to obtain solution D; solution D was reacted at 160℃ for 2 to 3 days to obtain the reaction product; the reaction product was activated by immersion in N,N-dimethylformamide and then vacuum dried to obtain Ni-NH2-MOF powder.

[0037] III. Preparation of Ni-NH2-MOF@HPP-COF composite materials:

[0038] ① Dissolve Ni-NH2-MOF powder in N,N-dimethylformamide and sonicate for a period of time to obtain Ni-NH2-MOF solution;

[0039] ② Dissolve HPP-COF powder in methanol and sonicate for a period of time to obtain HPP-COF solution;

[0040] ③ Under stirring conditions, HPP-COF solution is added to Ni-NH2-MOF solution, then glacial acetic acid is added, and stirring is continued for a period of time to obtain solution E;

[0041] ④ Transfer solution E to a reaction vessel and react at 80℃ for 18-30 h to obtain the reaction product; immerse the reaction product in N,N-dimethylformamide and methanol for alternating activation for 2-3 days, with alternating solvent activation every 3-5 h, and finally vacuum dry to obtain the Ni-NH2-MOF@HPP-COF composite material for adsorption and separation of perfluorinated carbon gas / nitrogen.

[0042] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the mass ratio of 1,4-phenylenediboric acid to the volume ratio of 1,4-dioxane in step one ① is (0.5g~0.6g):25mL. The other steps are the same as in Specific Implementation Method One.

[0043] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that: the mass ratio of 2,3,6,7,10,11-hexahydroxytriphenylene in step 1 ② to the volume ratio of preheated trimethylbenzene is (1.8g~2.0g):25mL; the preheating temperature in step 1 ② is 55℃~65℃. Other steps are the same as in Specific Implementation Method 1 or 2.

[0044] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the volume ratio of glacial acetic acid, solution A, and solution B in step one ③ is 1:10:10. The other steps are the same as in Specific Implementation Methods One to Three.

[0045] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: in step one, the reaction product is immersed in methanol for activation for 2 to 3 days; the vacuum drying temperature in step one, step four is 70°C to 80°C. Other steps are the same as in Specific Implementation Methods One to Four.

[0046] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in the following ways: the molar ratio of Ni(NO3)2·6H2O and 3-aminoisonicotinic acid in step two is 1:2; the molar ratio of Ni(NO3)2·6H2O to the volume ratio of N,N-dimethylformamide in step two is 1 mmol: 10 mL; the activation of the reaction product by immersing it in N,N-dimethylformamide for 2 to 3 days is described in step two; and the vacuum drying temperature in step two is 70°C to 80°C. Other steps are the same as in Specific Implementation Methods One to Five.

[0047] Specific embodiment seven: the difference between this embodiment and one of the specific embodiments one to six is that the mass to volume ratio of the Ni-NH2-MOF powder to N,N-dimethylformamide in step three ① is (0.1g~0.15g):200mL; the ultrasonic treatment time in step three ① is 10min~20min. The other steps are the same as specific embodiments one to six.

[0048] Specific embodiment eight: the difference between this embodiment and one of the specific embodiments one to seven is that the mass to volume ratio of the HPP-COF powder to methanol in step three ② is (0.1g~0.2g):200mL; the ultrasonic treatment time in step three ② is 10min~20min. The other steps are the same as specific embodiments one to seven.

[0049] Specific embodiment nine: the difference between this embodiment and one of the specific embodiments one to eight is that the mass ratio of Ni-NH2-MOF to HPP-COF in solution E in step three ③ is 1:1; the volume ratio of the HPP-COF solution to glacial acetic acid in step three ③ is 20:1; the time of continuous stirring in step three ③ is 3h~5h; the stirring speed in step three ③ is 300rpm~500rpm; the temperature of vacuum drying in step three ④ is 70℃~80℃, and the vacuum drying time in step three ④ is 10h~14h. The other steps are the same as specific embodiments one to eight.

[0050] Specific embodiment ten: this embodiment is the use of Ni-NH2-MOF@HPP-COF composite material for adsorptive separation of perfluorocarbon gas and nitrogen; the perfluorocarbon gas is CF4, C2F6 or C3F8.

[0051] The beneficial effects of the present application are verified by the following examples:

[0052] Example 1: a preparation method of a Ni-NH2-MOF@HPP-COF composite material for adsorptive separation of perfluorocarbon gas / nitrogen, specifically completed by the following steps:

[0053] I. Preparation of HPP-COF powder:

[0054] ①, 0.55g 1,4-benzenediboronic acid was dissolved in 25mL ice bath 1,4-dioxane to obtain solution A;

[0055] ②, 1.98g 2,3,6,7,10,11-hexahydroxytriphenylamine was dissolved in 25mL 60℃ triphenylmethane to obtain solution B;

[0056] ③, solution A and solution B were mixed uniformly, then 2.5mL glacial acetic acid was added and mixed uniformly to obtain solution C;

[0057] IV. transferring solution C into a reaction kettle, reacting at 120°C for 6 days to obtain a reaction product; immersing the reaction product into methanol for activation for 3 days, and finally drying under vacuum at 80°C to obtain HPP-COF powder;

[0058] II. preparing Ni-NH2-MOF powder:

[0059] dissolving 1 mmol Ni(NO3)2·6H2O and 2 mmol 3-amino isonicotinic acid in 10 mL N,N-dimethylformamide to obtain solution D; reacting solution D at 160°C for 3 days to obtain a reaction product; immersing the reaction product into N,N-dimethylformamide for activation for 3 days, and then drying under vacuum at 80°C to obtain Ni-NH2-MOF powder;

[0060] III. preparing Ni-NH2-MOF@HPP-COF composite material:

[0061] I. dissolving Ni-NH2-MOF powder in N,N-dimethylformamide, and ultrasonic treating for 15 min to obtain Ni-NH2-MOF solution;

[0062] The mass of Ni-NH2-MOF powder to the volume of N,N-dimethylformamide in step III 1 is 0.1 g:200 mL;

[0063] II. dissolving HPP-COF powder in methanol, and ultrasonic treating for 15 min to obtain HPP-COF solution;

[0064] The mass of HPP-COF powder to the volume of methanol in step III 2 is 0.1 g:200 mL;

[0065] III. adding HPP-COF solution into Ni-NH2-MOF solution under the condition of stirring at 400 rpm, and then adding glacial acetic acid, and continuously stirring for 3 h to obtain solution E;

[0066] The mass ratio of Ni-NH2-MOF to HPP-COF in solution E in step III 3 is 1:1;

[0067] The volume ratio of HPP-COF solution to glacial acetic acid in step III 3 is 20:1;

[0068] iv. Solution E is transferred into a reaction kettle and reacted at 80°C for 24h to obtain a reaction product; the reaction product is alternately activated in N,N-dimethylformamide and methanol for 3 days, and the activation is performed every 4h, and finally vacuum dried at 80°C for 12h to obtain a Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen.

[0069] Example 2: The difference between this example and Example 1 is that the mass ratio of Ni-NH2-MOF to HPP-COF in solution E in step three ③ is 1:0.5. Other steps and parameters are the same as those in Example 1.

[0070] Example 3: The difference between this example and Example 1 is that the mass ratio of Ni-NH2-MOF to HPP-COF in solution E in step three ③ is 1:0.75. Other steps and parameters are the same as those in Example 1.

[0071] Example 4: The difference between this example and Example 1 is that the mass ratio of Ni-NH2-MOF to HPP-COF in solution E in step three ③ is 1:1.25. Other steps and parameters are the same as those in Example 1.

[0072] Example 5: The difference between this example and Example 1 is that the mass ratio of Ni-NH2-MOF to HPP-COF in solution E in step three ③ is 1:1.5. Other steps and parameters are the same as those in Example 1.

[0073] Example 6: The difference between this example and Example 1 is that solution E is transferred into a reaction kettle and reacted at 80°C for 18h to obtain a reaction product in step three ④. Other steps and parameters are the same as those in Example 1.

[0074] Example 7: The difference between this example and Example 1 is that solution E is transferred into a reaction kettle and reacted at 80°C for 22h to obtain a reaction product in step three ④. Other steps and parameters are the same as those in Example 1.

[0075] Example 8: The difference between this example and Example 1 is that solution E is transferred into a reaction kettle and reacted at 80°C for 26h to obtain a reaction product in step three ④. Other steps and parameters are the same as those in Example 1.

[0076] Example 9: The difference between this example and Example 1 is that solution E is transferred into a reaction kettle and reacted at 80°C for 30h to obtain a reaction product in step three ④. Other steps and parameters are the same as those in Example 1.

[0077] Gas adsorption analysis was performed by static volumetric method using a BSD-660M A3M analyzer. This system measures the adsorption capacity of carbon tetrafluoride (CF4) and nitrogen (N2) in a mixture of CF4 and N2 (volume ratio of CF4 to N2 is 1:9) under controlled conditions, and its integrated in-situ degassing function ensures the integrity of sample preparation. Before measurement, the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen was vacuum activated in methanol at 373 K for 6 hours to remove residual solvents and adsorbed contaminants.

[0078] Figure 1 Adsorption capacity of CF4 of the Ni-NH2-MOF@HPP-COF composite material prepared for Example 1, Examples 6-9;

[0079] From Figure 1 It can be seen that the adsorption capacity of CF4 gradually increases with the increase of reaction time, indicating that the structure of the composite material is continuously optimized with the prolongation of reaction time, the pore structure tends to be perfect, and the active sites are gradually fully exposed. When the reaction time reaches 24 hours, the adsorption capacity reaches the peak, at this time the structure and interface coupling state of the material are optimal, forming a more efficient hierarchical pore structure and stronger adsorption sites, thereby significantly improving the adsorption capacity of CF4. However, when the reaction time exceeds 24 hours, the adsorption capacity begins to decrease, which may be due to the degradation of the material structure caused by too long reaction time, such as pore collapse, partial structure disorder or interface overgrowth blocking the pore, etc., ultimately leading to the decrease of adsorption performance.

[0080] Gas adsorption analysis was performed by static volumetric method using a BSD-660M A3M analyzer. This system measures the adsorption capacity of carbon tetrafluoride (CF4) and nitrogen (N2) in a mixture of CF4 and N2 (volume ratio of CF4 to N2 is 1:9) under controlled conditions, and its integrated in-situ degassing function ensures the integrity of sample preparation. Before measurement, the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen was vacuum activated in methanol at 373 K for 6 hours to remove residual solvents and adsorbed contaminants.

[0081] Figure 2 Adsorption capacity of CF4 of the Ni-NH2-MOF@HPP-COF composite material prepared for Example 1-5;

[0082] The CF4 adsorption capacity in the figure increases first and then decreases with the increase of the COF / MOF molar ratio, and reaches a peak in the molar ratio interval of 1.25-1.5. The increase in adsorption capacity is due to the introduction of COF in this stage and the formation of hierarchical pore structure and interface synergistic effect with MOF, which enhances the accessibility of adsorption sites and gas diffusion efficiency; while the adsorption capacity decreases after exceeding the optimal ratio, because the excess COF blocks the MOF channels and covers the active sites, resulting in imbalance of material structure and reduction of adsorption performance.

[0083] The BSD-660M A3M analyzer was used to perform gas adsorption analysis by static volume method. The system measures the adsorption capacity of carbon tetrafluoride (CF4) and nitrogen (N2) in a mixed gas of CF4 and N2 (volume ratio of CF4 and N2 is 1:9) under controlled conditions, and the integrated in-situ degassing function ensures the integrity of sample preparation. Before measurement, the Ni-NH2-MOF@HPP-COF composite material used for adsorption separation of perfluorocarbon gas / nitrogen was vacuum activated in methanol at 373 K for 6 hours to remove residual solvents and adsorbed contaminants.

[0084] Figure 3 The figure shows the characterization of the cyclic desorption-adsorption selectivity and cyclic desorption-adsorption capacity of the Ni-NH2-MOF@HPP-COF composite material prepared in Example 1 for CF4;

[0085] In the figure, after 10 cycles of adsorption-desorption, the CF4 adsorption capacity of the material only shows a slight decrease, while its selectivity for CF4 / N2 remains at a high level and almost no decay is observed, showing excellent cycle stability. This indicates that the material not only maintains the integrity of the structure during multiple adsorption-desorption processes, avoiding pore collapse or active site deactivation, but also has highly stable surface chemical properties and separation selectivity, and has good potential for practical application.

Claims

1. A method for preparing a Ni-NH2-MOF@HPP-COF composite material for adsorption and separation of perfluorinated carbon gas / nitrogen, characterized in that... The preparation method is specifically completed according to the following steps: I. Preparation of HPP-COF powder: ①, 1, 4-benzenediboronic acid is dissolved in an ice bath 1, 4-dioxane to obtain solution A; ②, 2, 3, 6, 7, 10, 11-hexahydroxytriphenyl is dissolved in preheated trimethylbenzene to obtain solution B; ③, solution A and solution B are mixed uniformly, and glacial acetic acid is added and mixed uniformly to obtain solution C; ④, solution C is transferred into a reaction kettle, and is reacted at 120 DEG C for 4-6 days to obtain a reaction product; the reaction product is immersed in methanol for activation, and finally vacuum dried to obtain HPP-COF powder; II. Preparation of Ni-NH2-MOF powder: Ni (NO3) 2.6H2O and 3-aminoisonicotinic acid are dissolved in N, N-dimethylformamide to obtain solution D; solution D is reacted at 160 DEG C for 2-3 days to obtain a reaction product; the reaction product is immersed in N, N-dimethylformamide for activation, and then vacuum dried to obtain Ni-NH2-MOF powder; III. Preparation of Ni-NH2-MOF@HPP-COF composite material: ①, Ni-NH2-MOF powder is dissolved in N, N-dimethylformamide, and ultrasonic treated for a period of time to obtain a Ni-NH2-MOF solution; ②, HPP-COF powder is dissolved in methanol, and ultrasonic treated for a period of time to obtain a HPP-COF solution; ③, under stirring, the HPP-COF solution is added to the Ni-NH2-MOF solution, and then glacial acetic acid is added, and stirring is continued for a period of time to obtain solution E; ④, solution E is transferred into a reaction kettle, and is reacted at 80 DEG C for 18-30 hours to obtain a reaction product; the reaction product is immersed in N, N-dimethylformamide and methanol for alternating activation for 2-3 days, and the alternating solvent activation is carried out every 3-5 hours, and finally vacuum dried to obtain a Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen.

2. The preparation method of the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen according to claim 1, characterized in that The mass of 1, 4-benzenediboronic acid to the volume of 1, 4-dioxane in step 1 ① is (0.5g-0.6g):25mL.

3. The preparation method of the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen according to claim 1, characterized in that The mass of 2, 3, 6, 7, 10, 11-hexahydroxytriphenyl to the volume of preheated trimethylbenzene in step 1 ② is (1.8g-2.0g):25mL; the preheating temperature in step 1 ② is 55 DEG C-65 DEG C.

4. The preparation method of the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen according to claim 1, characterized in that The volume ratio of glacial acetic acid, solution A and solution B in step 1 ③ is 1:10:

10.

5. The preparation method of the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen according to claim 1, characterized in that The reaction product is immersed in methanol for activation for 2-3 days in step 1 ④; the vacuum drying temperature in step 1 ④ is 70 DEG C-80 DEG C.

6. The preparation method of the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen according to claim 1, characterized in that The molar ratio of Ni(NO3)2·6H2O to 3-amino-isonicotinic acid in step two is 1:2; the molar ratio of Ni(NO3)2·6H2O to N,N-dimethylformamide in step two is 1 mmol:10 mL; the activation time of the reaction product in step two is 2-3 days; the vacuum drying temperature in step two is 70-80℃.

7. The preparation method of the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen according to claim 1, characterized in that The mass ratio of Ni-NH2-MOF powder to N,N-dimethylformamide in step three ① is (0.1-0.15 g):200 mL; the ultrasonic treatment time in step three ① is 10-20 min.

8. The preparation method of the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen according to claim 1, characterized in that The mass ratio of HPP-COF powder to methanol in step three ② is (0.1-0.2 g):200 mL; the ultrasonic treatment time in step three ② is 10-20 min.

9. The preparation method of the Ni-NH2-MOF@HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen according to claim 1, characterized in that The mass ratio of Ni-NH2-MOF to HPP-COF in solution E in step three ③ is 1:1; the volume ratio of HPP-COF solution to glacial acetic acid in step three ③ is 20:1; the continuous stirring time in step three ③ is 3-5 h; the stirring speed is 300-500 rpm; the vacuum drying temperature in step three ④ is 70-80℃, and the vacuum drying time is 10-14 h.

10. The use of the Ni-NH2-MOF@HPP-COF composite material prepared by the preparation method of claim 1 for adsorbing and separating perfluorocarbon gas / nitrogen. The application is used for adsorbing and separating perfluorocarbon gas and nitrogen; the perfluorocarbon gas is CF4, C2F6 or C3F8.

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