Zirconium-based MOF material and application thereof in acid gas degradation

Abstract

The invention discloses a zirconium-based MOF material and application thereof in acidic gas degradation, and belongs to the technical field of adsorbents, the overall strength of the zirconium-based MOF material is improved by taking a layered structure of a zinc-aluminum layered carrier as a carrier, and after amination treatment of 3-aminopropyltriethoxysilane, Lewis alkaline sites on the surface are increased, so that the adsorption capacity of the zirconium-based MOF material is improved, and the adsorption capacity of the zirconium-based MOF material is improved. According to the zirconium-based MOF material disclosed by the invention, the zirconium-based MOF material is added into acidic VOCs, so that the bonding strength of electrophilic carbonyl groups or carboxyl groups in acidic VOCs is improved, the hydrophobic effect of the zirconium-based MOF material can be improved, and the phenomenon that the structure is damaged due to water erosion in wet industrial flue gas is avoided; a zirconium-based MOF adsorption material is obtained through a hydrothermal method, titanium-based MOF is subjected to ion exchange modification, titanium-based MOF grows on the surface in situ, the titanium / zirconium-based dual-MOF adsorption material of a sandwich structure is obtained, the specific surface area, porosity and overall strength of the zirconium-based MOF material are improved, and adsorption and conversion of the zirconium-based MOF material to harmful gas molecules are improved to a great extent.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of adsorbents, and particularly relates to a zirconium-based MOF material and application thereof in degradation of acid gases. BACKGROUND

[0002] In recent years, traditional means and ideas have not made breakthrough progress. Due to the rapid development of nanotechnology and the gradual maturity of nanomaterials, various porous materials such as molecular sieves, activated carbon, carbon nanotubes and porous polymers have been proposed. However, the nanopore of the metal organic framework structure is the most advantageous and promising waste gas treatment material. Compared with traditional inorganic and organic porous materials, the three-dimensional regular structure of the metal organic framework has absolute advantages in many indicators of waste gas treatment materials, and the continuous flow production preparation technology can greatly reduce the production cost.

[0003] A method for adsorbing and separating sulfur-containing acid gases is disclosed in Chinese Patent No. CN105833662B. The anionic metal organic framework material contains a large number of regularly arranged negatively charged inorganic anion functional groups, and the size of the organic ligand can be adjusted to controllably adjust the size of the MOF material pore size, or the pore space structure can be adjusted by inserting the structure. The negatively charged inorganic anion can form an electrostatic environment in the confined space of the MOF material, and can selectively adsorb sulfur-containing acid gas molecules by forming electrostatic interaction with the electron-deficient atoms of the acid gas, thereby realizing high-capacity and high-selectivity separation of sulfur-containing acid gas. However, the negatively charged inorganic anion functional group in the scheme is SiF6 2- In humid industrial flue gas, the water content is generally 10-15%, and the Si-F bond of SiF6 2- is easily attacked and hydrolyzed by water molecules, resulting in collapse of the skeleton and thus degradation of the cyclic adsorption capacity of the MOF. SUMMARY

[0004] The application aims to provide a zirconium-based MOF material and application thereof in degradation of acid gases. The layered structure of the zinc-aluminum layered carrier is used as a carrier to improve the overall strength of the zirconium-based MOF material. After 3-aminopropyltriethoxysilane amination treatment, the Lewis base sites on the surface are increased, and the hydrophobicity of the zirconium-based MOF material is improved, thereby avoiding erosion by water in humid industrial flue gas, structural damage and decline in adsorption effect.

[0005] The object of the application can be achieved by the following technical solutions:

[0006] A preparation method of a zirconium-based MOF material, comprising the following steps:

[0007] Step one: titanium / zirconium-based MOF adsorbent material, 2,5-dihydroxyterephthalic acid and N,N-dimethylformamide were added to a reaction kettle lined with polytetrafluoroethylene, stirred at 20-25°C and 500-600 r / min for 20-30 min, then titanium isopropylate was added, and stirring was continued for 20-30 min, then acetic acid solution was added, and ultrasonic dispersion was carried out for 40-60 min, heated to 120-140°C, and stirring was continued for 24-26 h, then naturally cooled to room temperature, filtered, the filter cake was washed with N,N-dimethylformamide and methanol for 2-3 times respectively, and vacuum dried at 60-80°C for 1-2 h, to obtain a titanium / zirconium-based double MOF adsorbent material.

[0008] Step two: titanium / zirconium-based double MOF adsorbent material, anhydrous ethanol and deionized water were added to a reaction kettle, stirred at 60-70°C and 500-600 r / min for 10-15 min, then 3-aminopropyl triethoxysilane was added, the pH value was adjusted to 3-4 with hydrochloric acid solution, and stirring was continued for 6-7 h, then naturally cooled to room temperature, filtered, the filter cake was washed with deionized water and anhydrous ethanol for 2-3 times respectively, and vacuum dried at 60-80°C for 1-2 h, to obtain a zirconium-based MOF material.

[0009] Further, the amount ratio of titanium / zirconium-based MOF adsorbent material, 2,5-dihydroxyterephthalic acid, N,N-dimethylformamide, titanium isopropylate and acetic acid solution is 40-50 g:80-90 g:2-3 L:100-120 g:100-120 mL.

[0010] Further, the amount ratio of titanium / zirconium-based double MOF adsorbent material, anhydrous ethanol, deionized water and 3-aminopropyl triethoxysilane is 50-60 g:1-2 L:3-4 L:70-80 mL.

[0011] Further, the titanium / zirconium-based MOF adsorbent material is prepared by the following steps:

[0012] Step one: titanium / zirconium-based MOF adsorbent material, 2,5-dihydroxyterephthalic acid and N,N-dimethylformamide were added to a reaction kettle lined with polytetrafluoroethylene, stirred at 20-25°C and 500-600 r / min for 20-30 min, then titanium isopropylate was added, and stirring was continued for 20-30 min, then acetic acid solution was added, and ultrasonic dispersion was carried out for 40-60 min, heated to 120-140°C, and stirring was continued for 24-26 h, then naturally cooled to room temperature, filtered, the filter cake was washed with N,N-dimethylformamide and methanol for 2-3 times respectively, and vacuum dried at 60-80°C for 1-2 h, to obtain a titanium / zirconium-based double MOF adsorbent material.

[0013] Further, the amount ratio of the titanium / zirconium-based MOF adsorbent material, 2,5-dihydroxyterephthalic acid, N,N-dimethylformamide, isopropyl titanate and acetic acid solution is 40-50 g:80-90 g:2-3 L:100-120 g:100-120 mL.

[0014] Further, the titanium / zirconium-based MOF adsorbent material is prepared by the following steps:

[0015] The zirconium-based MOF adsorbent material and toluene are added into a reaction kettle lined with polytetrafluoroethylene, stirred at 20-25℃ and 500-600 r / min for 20-30 min, then tetrabutyl titanate is added, heated to 100-120℃ and continuously stirred for 24-26 h, naturally cooled to room temperature, filtered, the filter cake is washed with methanol for 2-3 times, centrifuged at 15000-16000 r / min for 2-3 times, then the product is washed with deionized water and anhydrous ethanol for 2-3 times respectively, vacuum dried at 60-80℃ for 1-2 h, to obtain the titanium / zirconium-based MOF adsorbent material.

[0016] Further, the amount ratio of the zirconium-based MOF adsorbent material, toluene and tetrabutyl titanate is 80-90 g:2-3 L:25-28 mL.

[0017] Further, the zirconium-based MOF adsorbent material is prepared by the following steps:

[0018] The zinc-aluminum layered carrier, terephthalic acid and N,N-dimethylformamide are added into a reaction kettle lined with polytetrafluoroethylene, stirred at 20-25℃ and 500-600 r / min for 20-30 min, then zirconium chloride is added, continuously stirred for 20-30 min, then acetic acid solution is added, ultrasonic dispersed for 40-60 min, heated to 120-140℃, continuously stirred for 24-26 h, naturally cooled to room temperature, filtered, the filter cake is washed with N,N-dimethylformamide and methanol for 2-3 times respectively, vacuum dried at 60-80℃ for 1-2 h, to obtain the zirconium-based MOF adsorbent material.

[0019] Further, the amount ratio of the zinc-aluminum layered carrier, terephthalic acid, N,N-dimethylformamide, zirconium chloride and acetic acid solution is 40-50 g:100-200 g:2-3 L:140-150 g:100-120 mL.

[0020] Further, the zinc-aluminum layered carrier is prepared by the following steps:

[0021] Zinc nitrate hexahydrate, urea and deionized water are added into a reaction kettle, stirred at 60-70 DEG C and 500-600r / min for 10-15min, then alumina is added, continue to stir for 30-40min, heated to 130-140 DEG C and aged for 48-50h, filtered, the filter cake is washed with deionized water and anhydrous ethanol until the last washing liquid is neutral, vacuum dried at 60-80 DEG C for 1-2h, to obtain a zinc-aluminum layered carrier.

[0022] Further, the amount ratio of zinc nitrate hexahydrate, urea, deionized water and alumina is 50-60mL: 20-30g: 800-900mL: 22-25mL.

[0023] The application further provides application of the zirconium-based MOF material in acid gas degradation.

[0024] The application has the following beneficial effects:

[0025] 1. The zirconium-based MOF material prepared by the application, by using the layered structure of the zinc-aluminum layered carrier as a carrier, the overall strength of the zirconium-based MOF material is improved, after the 3-aminopropyl triethoxysilane is aminated, the Lewis base sites on the surface are increased, so that the combination strength of the electrophilic carbonyl or carboxyl in the acid VOCs is improved, and the 3-aminopropyl triethoxysilane after amination has hydrophobicity, which can improve the hydrophobic effect of the zirconium-based MOF material, avoid being eroded by moisture in the humid industrial flue gas, and cause the structure to be destroyed and the adsorption effect to be reduced.

[0026] 2. The titanium / zirconium-based double MOF adsorption material of the application, the zirconium-based MOF adsorption material is obtained by a hydrothermal method, and then modified by titanium ion exchange, so as to increase the specific surface area and the pore, and the titanium-based MOF is in-situ grown on the upper and lower surfaces of the double MOF by esterification reaction of the hydroxyl and the carboxyl by using a wet chemical method, to obtain a sandwich structure titanium / zirconium-based double MOF adsorption material, the titanium deposited in the pores of the zirconium-based MOF adsorption material provides part of the titanium source for the formation of the sandwich structure, and further increases the stability of the sandwich structure. The formation of the sandwich structure increases the specific surface area and the porosity of the zirconium-based MOF material, and also improves the overall strength of the zirconium-based MOF material, greatly improves the adsorption and conversion of the harmful gas molecules by the zirconium-based MOF material; the titanium in the titanium-based MOF has photocatalytic activity and can photocatalytically degrade the harmful components of the acid gas.

[0027] 3. The present application increases the Lewis base sites on the surface of the titanium / zirconium-based double MOF adsorbent material by amination treatment, thereby improving the binding strength of electrophilic carbonyl or carboxyl groups in acidic VOCs, and the titanium / zirconium-based double MOF adsorbent material after amination treatment has good hydrophobicity. After drying and recycling for 100 times after washing with deionized water, it still has excellent physical and chemical properties and adsorption efficiency. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] Embodiment 1: A preparation method of a zirconium-based MOF material, comprising the following steps:

[0030] S1: 50 mL of zinc nitrate hexahydrate, 20 g of urea and 800 mL of deionized water are added to a reaction kettle, stirred at 60°C and 500 r / min for 10 min, then 22 mL of aluminum oxide is added, and stirring is continued for 30 min. Heating to 130°C for 48 h, suction filtration, washing the filter cake with deionized water and anhydrous ethanol until the last washing liquid is neutral, and vacuum drying at 60°C for 1 h to obtain a zinc-aluminum layered carrier.

[0031] A zinc-aluminum layered carrier is obtained by a hydrothermal synthesis method, with urea providing an alkaline environment. The inherent two-dimensional structural characteristics, such as large specific surface area, exchangeable anions and flexible interlayer space, make it a very promising pollutant adsorbent material. In addition to electrostatic adsorption, the adsorption process is also related to the hydrogen bonds formed between OH- in LDH and functional groups in pollutants. In addition, LDH has a large number of surface defect sites, thereby improving the catalytic activity of LDH, which has great potential in adsorption desulfurization.

[0032] S2: 40 g of zinc-aluminum layered carrier, 100 g of terephthalic acid and 2 L of N,N-dimethylformamide are added to a reaction kettle lined with polytetrafluoroethylene, stirred at 20°C and 500 r / min for 20 min, then 140 g of zirconium chloride is added, and stirring is continued for 20 min, then 100 mL of acetic acid solution is added, ultrasonic dispersion is performed for 40 min, heating to 120°C, and stirring is continued for 24 h, natural cooling to room temperature, filtration, washing the filter cake with N,N-dimethylformamide and methanol for 2 times respectively, and vacuum drying at 60°C for 1 h to obtain a zirconium-based MOF adsorbent material.

[0033] S3: 80 g of zirconium-based MOF adsorbent material and 2 L of toluene were added to a reaction kettle lined with polytetrafluoroethylene, stirred at 20 DEG C and 500 r / min for 20 min, then 25 mL of tetrabutyl titanate was added, heated to 100 DEG C and continued to stir for 24 h, naturally cooled to room temperature, filtered, the filter cake was washed twice with methanol, centrifuged twice at 15000 r / min, then the product was washed twice with deionized water and anhydrous ethanol respectively, and vacuum dried at 60 DEG C for 1 h to obtain a titanium / zirconium-based MOF adsorbent material.

[0034] The specific surface area of the zirconium-based MOF adsorbent material was improved to some extent by the synthesis modification of titanium ion exchange, and part of the zirconium ions with larger radius in the structure of the zirconium-based MOF adsorbent material were successfully replaced by titanium ions with smaller radius, so that the pore size and specific surface area were improved.

[0035] S4: 40 g of titanium / zirconium-based MOF adsorbent material, 80 g of 2,5-dihydroxyterephthalic acid and 2 L of N,N-dimethylformamide were added to a reaction kettle lined with polytetrafluoroethylene, stirred at 20 DEG C and 500 r / min for 20 min, then 100 g of isopropyl titanate was added, continued to stir for 20 min, then 100 mL of acetic acid solution was added, ultrasonic dispersion for 40 min, heated to 120 DEG C and continued to stir for 24 h, naturally cooled to room temperature, filtered, the filter cake was washed twice with N,N-dimethylformamide and methanol respectively, and vacuum dried at 60 DEG C for 1 h to obtain a titanium / zirconium-based double MOF adsorbent material.

[0036] The zirconium-based MOF adsorbent material was prepared by a hydrothermal method, the specific surface area and the pore were increased by titanium modification, and the titanium-based MOF was in-situ grown on the upper and lower surfaces of the double MOF by esterification reaction of hydroxyl and carboxyl group by using wet chemical method, thereby obtaining a titanium / zirconium-based double MOF adsorbent material.

[0037] S5: 50 g of titanium / zirconium-based double MOF adsorbent material, 1 L of anhydrous ethanol and 3 L of deionized water were added to a reaction kettle, stirred at 60 DEG C and 500 r / min for 10 min, then 70 mL of 3-aminopropyltriethoxysilane was added, the pH value was adjusted to 3 with hydrochloric acid solution, continued to stir for 6 h, naturally cooled to room temperature, filtered, the filter cake was washed twice with deionized water and anhydrous ethanol respectively, and vacuum dried at 60 DEG C for 1 h to obtain a zirconium-based MOF material.

[0038] Example 2: A preparation method of a zirconium-based MOF material, comprising the following steps:

[0039] S1: 55 mL of zinc nitrate hexahydrate, 25 g of urea and 850 mL of deionized water were added to a reaction kettle, stirred at 65 °C and 550 r / min for 12.5 min, then 23.5 mL of aluminum oxide was added, and stirring was continued for 35 min, heated to 135 °C and aged for 49 h, filtered, the filter cake was washed with deionized water and anhydrous ethanol until the last washing liquid was neutral, and vacuum dried at 70 °C for 1.5 h to obtain a zinc-aluminum layered carrier.

[0040] S2: 45 g of zinc-aluminum layered carrier, 150 g of terephthalic acid and 2.5 L of N,N-dimethylformamide were added to a reaction kettle lined with polytetrafluoroethylene, stirred at 22.5 °C and 550 r / min for 25 min, then 145 g of zirconium chloride was added, and stirring was continued for 25 min, then 110 mL of acetic acid solution was added, ultrasonic dispersion was carried out for 50 min, heated to 130 °C, and stirring was continued for 25 h, and then naturally cooled to room temperature, filtered, the filter cake was washed with N,N-dimethylformamide and methanol for 2 times respectively, and vacuum dried at 70 °C for 1.5 h to obtain a zirconium-based MOF adsorbent material.

[0041] S3: 85 g of zirconium-based MOF adsorbent material and 2.5 L of toluene were added to a reaction kettle lined with polytetrafluoroethylene, stirred at 22.5 °C and 550 r / min for 25 min, then 26.5 mL of tetrabutyl titanate was added, heated to 110 °C and stirring was continued for 25 h, and then naturally cooled to room temperature, filtered, the filter cake was washed with methanol for 2 times, centrifuged at 15500 r / min for 2 times, and then the product was washed with deionized water and anhydrous ethanol for 2 times respectively, and vacuum dried at 70 °C for 1.5 h to obtain a titanium / zirconium-based MOF adsorbent material.

[0042] S4: 45 g of titanium / zirconium-based MOF adsorbent material, 85 g of 2,5-dihydroxyterephthalic acid and 2.5 L of N,N-dimethylformamide were added to a reaction kettle lined with polytetrafluoroethylene, stirred at 22.5 °C and 550 r / min for 25 min, then 110 g of isopropyl titanate was added, and stirring was continued for 25 min, then 110 mL of acetic acid solution was added, ultrasonic dispersion was carried out for 50 min, heated to 130 °C, and stirring was continued for 25 h, and then naturally cooled to room temperature, filtered, the filter cake was washed with N,N-dimethylformamide and methanol for 2 times respectively, and vacuum dried at 70 °C for 1.5 h to obtain a titanium / zirconium-based double MOF adsorbent material.

[0043] S5: 55 g of titanium / zirconium-based double MOF adsorbent material, 1.5 L of anhydrous ethanol and 3.5 L of deionized water were added to the reaction kettle, stirred at 65°C and 550 r / min for 12.5 min, then 75 mL of 3-aminopropyl triethoxysilane was added, the pH value was adjusted to 3.5 with hydrochloric acid solution, and the stirring reaction was continued for 6.5 h, and then naturally cooled to room temperature, filtered, and the filter cake was washed with deionized water and anhydrous ethanol for 2 times respectively, and vacuum dried at 70°C for 1.5 h to obtain a zirconium-based MOF material.

[0044] Example 3: A preparation method of a zirconium-based MOF material, comprising the following steps:

[0045] S1: 60 mL of zinc nitrate hexahydrate, 30 g of urea and 900 mL of deionized water were added to the reaction kettle, stirred at 70°C and 600 r / min for 15 min, then 25 mL of aluminum oxide was added, and the stirring was continued for 40 min, heated to 140°C and aged for 50 h, and then filtered, and the filter cake was washed with deionized water and anhydrous ethanol until the last washing liquid was neutral, and then vacuum dried at 80°C for 2 h to obtain a zinc-aluminum layered carrier.

[0046] S2: 50 g of zinc-aluminum layered carrier, 200 g of terephthalic acid and 3 L of N,N-dimethylformamide were added to the reaction kettle lined with polytetrafluoroethylene, stirred at 25°C and 600 r / min for 30 min, then 150 g of zirconium chloride was added, and the stirring was continued for 30 min, then 120 mL of acetic acid solution was added, and ultrasonic dispersion was carried out for 60 min, heated to 140°C, and the stirring was continued for 26 h, and then naturally cooled to room temperature, filtered, and the filter cake was washed with N,N-dimethylformamide and methanol for 3 times respectively, and then vacuum dried at 80°C for 2 h to obtain a zirconium-based MOF adsorbent material.

[0047] S3: 90 g of zirconium-based MOF adsorbent material and 3 L of toluene were added to the reaction kettle lined with polytetrafluoroethylene, stirred at 25°C and 600 r / min for 30 min, then 28 mL of tetrabutyl titanate was added, heated to 120°C and the stirring was continued for 26 h, and then naturally cooled to room temperature, filtered, and the filter cake was washed with methanol for 3 times, centrifuged at 16,000 r / min for 3 times, and then the product was washed with deionized water and anhydrous ethanol for 3 times respectively, and then vacuum dried at 80°C for 2 h to obtain a titanium / zirconium-based MOF adsorbent material.

[0048] S4: 50 g of titanium / zirconium-based MOF adsorbent material, 90 g of 2,5-dihydroxyterephthalic acid, and 3 L of N,N-dimethylformamide were added to a reaction kettle lined with polytetrafluoroethylene, stirred at 25℃ and 600 r / min for 30 min, then 120 g of isopropyl titanate was added, and stirring was continued for 30 min, then 120 mL of acetic acid solution was added, ultrasonic dispersion was performed for 60 min, heating was performed to 140℃, and stirring was continued for 26 h, and then natural cooling was performed to room temperature, filtration was performed, the filter cake was washed with N,N-dimethylformamide and methanol for 3 times respectively, and vacuum drying was performed at 80℃ for 2 h, to obtain a titanium / zirconium-based double MOF adsorbent material.

[0049] S5: 60 g of the titanium / zirconium-based double MOF adsorbent material, 2 L of anhydrous ethanol, and 4 L of deionized water were added to a reaction kettle, stirring was performed at 70℃ and 600 r / min for 15 min, then 80 mL of 3-aminopropyltriethoxysilane was added, the pH value was adjusted to 4 by using a hydrochloric acid solution, and stirring was continued to react for 7 h, and then natural cooling was performed to room temperature, filtration was performed, the filter cake was washed with deionized water and anhydrous ethanol for 3 times respectively, and vacuum drying was performed at 80℃ for 2 h, to obtain a zirconium-based MOF material.

[0050] Comparative Example 1: on the basis of Example 3, without step S1 treatment, the zinc aluminum layered carrier in step S2 was removed, and the remaining steps were unchanged, to prepare a zirconium-based MOF material.

[0051] Comparative Example 2: on the basis of Example 3, the zirconium-based MOF adsorbent material in step S2 was replaced with an anion metal-organic framework material prepared by the preparation method described in paragraph 45 of the specification of a method for adsorbing and separating a sulfur-containing acidic gas disclosed in CN105833662B, to replace the zirconium-based MOF material in the original scheme.

[0052] Comparative Example 3: on the basis of Example 3, without step S3 treatment, the titanium / zirconium-based MOF adsorbent material in step S4 was replaced with the zirconium-based MOF adsorbent material in step S3, and the remaining steps were unchanged, to prepare a zirconium-based MOF material.

[0053] Comparative Example 4: on the basis of Example 3, without step S4 treatment, the titanium / zirconium-based MOF adsorbent material and the titanium-based MOF were directly stirred and uniformly mixed, and the remaining steps were unchanged, to prepare a zirconium-based MOF material.

[0054] The zirconium-based MOF materials obtained in Examples 1-3 and Comparative Examples 1-4 were subjected to performance testing, and were tested by using a BSD-PM specific surface area and micropore analyzer, to compare the specific surface area and average pore size parameters of the MOF materials in different examples and comparative examples.

[0055] The results are shown in Table 1:

[0056] Table 1 Performance test table of zirconium-based MOF material

[0057]

[0058] The zirconium-based MOF material was washed with deionized water, dried and used for 100 cycles, and then performance testing was performed, and the results are shown in Table 2:

[0059] Table 2 Performance test table of 100 cycles of water washing and regeneration

[0060]

[0061]

[0062] As can be seen from Table 1 and Table 2, the zirconium-based MOF material obtained in Example 1-Example 3 has a pore volume, adsorption volume ratio, pore size distribution, specific surface area, VOCs adsorption efficiency and NOx adsorption efficiency significantly better than the comparative example, indicating that the zirconium-based MOF material prepared by the present application has excellent specific surface area and porosity, and has good adsorption effect on VOCs and NOx.

[0063] In Comparative Example 1, the zinc-aluminum layered carrier is removed, and the zinc-aluminum layered carrier is a layered structure formed by a metal hydroxide, which can improve the photocatalytic activity of the titanium-based MOF as a carrier. The oxygen vacancies in the zinc-aluminum layered carrier can act as electron traps, prolonging the lifetime of photo-generated electrons, increasing the capture of carriers, and providing a stable porous structure and specific surface area, further improving the photocatalytic activity.

[0064] In Comparative Example 2, the zirconium-based MOF adsorption material is replaced by an anionic metal-organic framework material, which contains inorganic anion functional groups SiF6 2- In humid industrial flue gas, SiF6 2- The Si-F bond is easily attacked by water molecules and hydrolyzed, resulting in collapse of the framework, thereby causing the cycle adsorption capacity of the MOF to decay. After washing with deionized water and drying and recycling, the degree of hydrolysis increases, resulting in poor performance testing.

[0065] In Comparative Example 3, the titanium / zirconium-based MOF adsorption material is replaced by a zirconium-based MOF adsorption material, which is synthesized and modified by titanium ion exchange, resulting in replacement of some large radius zirconium ions by smaller radius titanium ions, increasing the specific surface area and pore size of the zirconium-based MOF adsorption material. The titanium deposited in the pores of the zirconium-based MOF adsorption material can provide part of the titanium source for the synthesis of the titanium-based MOF, thereby further increasing the binding strength of the titanium-based MOF grown in situ on the surface, and improving the stability of the sandwich structure.

[0066] In the comparative example 4, the titanium / zirconium-based MOF adsorbent material and the titanium-based MOF are stirred and mixed uniformly. The nanosize effect of the MOF material causes the MOF material to be easy to agglomerate. The dispersion can not be effectively achieved by the physical stirring and mixing. The titanium / zirconium-based MOF adsorbent material is obtained by in-situ generation of the titanium-based MOF from the zirconium-based MOF adsorbent material. The porosity and the specific surface area of the composite material are further improved. The structural stability of the material is improved.

[0067] While the embodiments of the application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the spirit and scope of the application.

Claims

1. A method for preparing a zirconium-based MOF material, characterized in that: The steps include: Step 1: Add titanium / zirconium-based MOF adsorbent material, 2,5-dihydroxyterephthalic acid and N,N-dimethylformamide to a polytetrafluoroethylene-lined reactor, stir at 20-25°C and 500-600r / min for 20-30min, then add isopropyl titanate, continue stirring for 20-30min, then add acetic acid solution, ultrasonically disperse for 40-60min, heat to 120-140°C, continue stirring for 24-26h, naturally cool, filter, wash, and vacuum dry to obtain a titanium / zirconium-based dual MOF adsorbent material; Step 2: Add titanium / zirconium-based dual MOF adsorption material, anhydrous ethanol and deionized water into a reactor, stir at 60-70°C and 500-600r / min for 10-15 minutes, then add 3-aminopropyltriethoxysilane, adjust the pH value to 3-4 with hydrochloric acid solution, continue stirring and reacting for 6-7 hours, cool naturally, filter, wash, and vacuum dry to obtain a zirconium-based MOF material.

2. The method for preparing a zirconium-based MOF material according to claim 1, wherein: The usage ratio of the titanium / zirconium-based MOF adsorption material, 2,5-dihydroxyterephthalic acid, N,N-dimethylformamide, isopropyl titanate and acetic acid solution is 40-50 g: 80-90 g: 2-3 L: 100-120 g: 100-120 mL.

3. The method for preparing a zirconium-based MOF material according to claim 1, wherein: The usage ratio of the titanium / zirconium-based dual MOF adsorption material, anhydrous ethanol, deionized water and 3-aminopropyltriethoxysilane is 50-60 g: 1-2 L: 3-4 L: 70-80 mL.

4. The method for preparing a zirconium-based MOF material according to claim 1, wherein: The titanium / zirconium-based MOF adsorption material is prepared by the following steps: Titanium / zirconium-based MOF adsorption material, 2,5-dihydroxyterephthalic acid and N,N-dimethylformamide are added to a polytetrafluoroethylene-lined reactor, stirred at 20-25°C and 500-600r / min for 20-30min, then isopropyl titanate is added, stirring is continued for 20-30min, then acetic acid solution is added, ultrasonic dispersion is carried out for 40-60min, heated to 120-140°C, stirring is continued for 24-26h, naturally cooled, filtered, washed, and vacuum dried to obtain a titanium / zirconium-based dual MOF adsorption material.

5. The method for preparing a zirconium-based MOF material according to claim 4, characterized in that: The usage ratio of the titanium / zirconium-based MOF adsorption material, 2,5-dihydroxyterephthalic acid, N,N-dimethylformamide, isopropyl titanate and acetic acid solution is 40-50 g: 80-90 g: 2-3 L: 100-120 g: 100-120 mL.

6. The method for preparing a zirconium-based MOF material according to claim 4, characterized in that: The titanium / zirconium-based MOF adsorption material is prepared by the following steps: The zirconium-based MOF adsorbent material and toluene are added to a polytetrafluoroethylene-lined reactor, stirred at 20-25° C. and 500-600 r / min for 20-30 min, and then tetrabutyl titanate is added. The mixture is heated to 100-120° C. and stirred for 24-26 h. The mixture is naturally cooled, filtered, washed, centrifuged at 15000-16000 r / min for 2-3 times, washed, and vacuum dried to obtain a titanium / zirconium-based MOF adsorbent material. The usage ratio of the zirconium-based MOF adsorption material, toluene and tetrabutyl titanate is 80-90 g: 2-3 L: 25-28 mL.

7. The method for preparing a zirconium-based MOF material according to claim 6, characterized in that: The zirconium-based MOF adsorption material is prepared by the following steps: The zinc-aluminum layered support, terephthalic acid and N,N-dimethylformamide were added to a polytetrafluoroethylene-lined reactor, stirred at 20-25°C and 500-600 r / min for 20-30 minutes, and then zirconium chloride was added, and the stirring was continued for 20-30 minutes. Then, acetic acid solution was added, and ultrasonic dispersion was carried out for 40-60 minutes. The mixture was heated to 120-140°C and stirred for 24-26 hours. The mixture was naturally cooled, filtered, washed, and vacuum dried to obtain a zirconium-based MOF adsorption material. The usage ratio of the zinc-aluminum layered carrier, terephthalic acid, N,N-dimethylformamide, zirconium chloride and acetic acid solution is 40-50g:100-200g:2-3L:140-150g:100-120mL.

8. The method for preparing a zirconium-based MOF material according to claim 7, characterized in that: The zinc-aluminum layered support is prepared by the following steps: Zinc nitrate hexahydrate, urea, and deionized water are added to a reactor, stirred at 60-70°C and 500-600 rpm for 10-15 minutes, and then alumina is added. The mixture is stirred for 30-40 minutes, heated to 130-140°C, aged for 48-50 hours, filtered, washed until neutral, and vacuum dried to obtain a zinc-aluminum layered carrier. The usage ratio of the zinc nitrate hexahydrate, urea, deionized water and aluminum oxide is 50-60 mL: 20-30 g: 800-900 mL: 22-25 mL.

9. A zirconium-based MOF material, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the zirconium-based MOF material according to claim 9 in acid gas degradation.

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