Polyacid-based metal-organic framework material, preparation method and application thereof

Abstract

This invention relates to the field of metal-organic framework (MOF) material preparation technology, and discloses a polyacid-based MOF material, its preparation method, and its applications. The chemical formula of this polyacid-based MOF material is M2(C7H8N4). n (HBW 12 O 40 )·mH2O, and the polyacid-based metal-organic framework material is a plate-like crystal, wherein M is Co and / or Ni, n is 1-6, and m is 3-10. According to the technical solution of the present invention, a sixteen-membered ring is formed by interconnecting metal atoms with Bim ligands, and (HBW 12 O 40 ) 4‑ The anionic unit constructs a unique three-dimensional structure with three connection points, which enables the obtained polyacid-based organometallic framework material to have better water absorption performance.

Description

Technical Field

[0001] This invention relates to the field of metal-organic framework material preparation technology, specifically to a polyacid-based metal-organic framework material, its preparation method, and its application. Background Technology

[0002] Air-to-water extraction technology, as an emerging technology, can effectively capture water resources from the air, providing clean drinking water globally. Unlike fog collection and air-cooling water extraction technologies, adsorption-based air-to-water extraction technology captures water molecules from the air using adsorbent materials, evaporates and desorbs the water molecules under heating, and finally collects the liquid water through a condensation device. Therefore, adsorption-based air-to-water extraction technology can overcome the limitations of climatic conditions, ensuring water supply with low consumption and high efficiency. Metal-organic frameworks (MOFs) have stable framework structures, resulting in high stability. Due to their high specific surface area and high porosity, they can rapidly adsorb water molecules from the air and have a high water adsorption capacity. Polyoxometalates, as classic transition metal oxide clusters, possess excellent hydrophilic properties due to their abundant oxygen atoms. Synthesizing novel polyoxometalate-based MOFs using polyoxometalates as metal nodes can improve the water adsorption performance of these materials. Therefore, polyoxometalate-based MOFs are highly promising water adsorption materials with significant application prospects in adsorption-based air-to-water extraction technology. Summary of the Invention

[0003] The purpose of this invention is to overcome the problem of low water absorption capacity in traditional absorbent materials in the prior art, and to provide a polyacid-based metal-organic framework material, its preparation method, and its application. In this invention, a sixteen-membered ring is formed by interconnecting metal atoms with Bim ligands, and (HBW... 12 O 40 ) 4- The anionic unit constructs a unique three-dimensional structure with three connection points, which enables the obtained polyacid-based organometallic framework material to have better water absorption performance.

[0004] To achieve the above objectives, the present invention provides a polyacid-based metal-organic framework material with the chemical formula M2(C7H8N4). n (HBW 12 O 40 ) m H2O, and the polyacid-based metal-organic framework material is a plate-like crystal, wherein M is Co and / or Ni, n is 1-6, and m is 3-10.

[0005] Preferably, the polyacid-based metal-organic framework material has a triclinic crystal system and a space group of [missing information]. P -1.

[0006] Preferably, the chemical formula of the polyacid-based metal-organic framework material is Co2(C7H8N4)4(HBW). 12 O 40 )·4H2O and / or Ni2(C7H8N4)4(HBW 12 O 40 )·7H2O.

[0007] A second aspect of the present invention provides a method for preparing the above-mentioned polyacid-based metal-organic framework material, the method comprising: carrying out a hydrothermal reaction in water with metal salts of Co and / or Ni, borotungstic acid and Bim ligand under acidic conditions.

[0008] Preferably, the mass ratio of the metal salt, the borotungstic acid, the Bim ligand, and water is (0.03-0.06):(0.03-0.06):(0.01-0.05):10, and more preferably (0.04-0.05):(0.04-0.05):(0.02-0.03):10.

[0009] Preferably, the metal salt is nickel chloride and / or cobalt chloride.

[0010] Preferably, the Bim ligand is bis(1H-imidazol-1-yl)methane.

[0011] Preferably, the hydrothermal reaction is carried out under acidic conditions with a pH of 3-4.

[0012] Preferably, the pH of the reaction system is adjusted to 3-4 using a hydrochloric acid solution with a concentration of 0.5-1.5 mol / L.

[0013] Preferably, the conditions for the hydrothermal reaction include: a temperature of 150-180℃ and a time of 80-120h.

[0014] The third aspect of this invention provides the application of the above-mentioned polyacid-based metal-organic framework materials in the water adsorption process.

[0015] According to the technical solution of this invention, a sixteen-membered ring is formed by interconnecting metal atoms with Bim ligands, and (HBW) 12 O 40 ) 4- The anionic unit constructs a unique three-dimensional structure with three connection points, which enables the obtained polyacid-based organometallic framework material to have better water absorption performance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the polyacid-based metal-organic framework material described in this invention; Figure 2This is a simplified three-dimensional structural diagram of the polyacid-based metal-organic framework material described in this invention; Figure 3 This is the XRD pattern of the polyacid-based metal-organic framework material prepared in Example 1; Figure 4 This is the infrared spectrum of the polyacid-based metal-organic framework material prepared in Example 1. Detailed Implementation

[0017] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] The chemical formula of the polyacid-based metal-organic framework material described in this invention is M2(C7H8N4). n (HBW 12 O 40 ) m H2O, and the polyacid-based metal-organic framework material is a plate-like crystal, wherein M is Co and / or Ni, n is 1-6, and m is 3-10.

[0020] In this invention, preferably, the polyacid-based metal-organic framework material has a triclinic crystal system and a space group of [missing information]. P -1.

[0021] In this invention, the chemical formula of the polyacid-based metal-organic framework material is Co2(C7H8N4)4(HBW). 12 O 40 )·4H2O and / or Ni2(C7H8N4)4(HBW 12 O 40 )·7H2O.

[0022] In some embodiments of the polyacid-based metal-organic framework material according to the present invention, the chemical formula of the polyacid-based metal-organic framework material is Co2(C7H8N4)4(HBW). 12 O 40 )·4H₂O, wherein Co has a oxidation state of +2, W has a oxidation state of +6, and B has a oxidation state of +3. Specifically, the parameters of the polyacid-based metal-organic framework material include: a triclinic crystal system and a space group ofP -1, the unit cell parameters include: a=12.038(6), b=14.536(7), c=22.142(10), α=76.417(6), β=83.598(6), γ=71.602(6), V =3571(3), Z=2. More specifically, the polyacid-based metal-organic framework material can be a red plate-like crystal.

[0023] In some embodiments of the polyacid-based metal-organic framework material according to the present invention, the chemical formula of the polyacid-based metal-organic framework material is Ni2(C7H8N4)4(HBW). 12 O 40 )·7H₂O, wherein Ni has a oxidation state of +2, W has a oxidation state of +6, and B has a oxidation state of +3. Specifically, the parameters of the polyacid-based metal-organic framework material include: a triclinic crystal system and a space group of P -1, unit cell parameters include: a=11.9953(13), b=14.4616(15), c=22.038(2), α=76.1230(10), β=83.6580(10), γ=71.4280(10), V =3515.7(6), Z=2. More specifically, the polyacid-based metal-organic framework material can be a green, plate-like crystal.

[0024] The polyacid-based metal-organic framework material according to the present invention Figure 1 This is a schematic diagram of the structure of the polyacid-based metal-organic framework material described in this invention. Specifically, Figure 1 The schematic diagram shown in (a) illustrates the Co atom, the Bim ligand, and (HBW) 12 O 40 ) 4- A schematic diagram of a polyacid-based metal-organic framework structure formed by anionic units. Figure 1 (c) shows a schematic diagram of a sixteen-membered ring formed by the interconnection of Co atoms and Bim ligands. The sixteen-membered ring units are connected by shared Co atoms to form a one-dimensional chain-like organometallic complex. Figure 1 (b) and Figure 1 (c) shows a partial schematic diagram of the structure of a polyoxometallic framework material. Figure 2 This is a simplified three-dimensional structural diagram of the polyacid-based metal-organic framework material described in this invention.

[0025] The method for producing the polyacid-based metal-organic framework material of the present invention includes: carrying out a hydrothermal reaction of metal salts of Co and / or Ni, borotungstic acid and Bim ligand in water under acidic conditions.

[0026] In the method described in this invention, the mass ratio of the metal salt, the borotungstic acid, the Bim ligand, and water can be (0.03-0.06):(0.03-0.06):(0.01-0.05):10, preferably (0.04-0.05):(0.04-0.05):(0.02-0.03):10.

[0027] In the method described in this invention, the metal salt may be nickel chloride and / or cobalt chloride. In the most preferred embodiment, the metal salt is nickel chloride.

[0028] In the method described in this invention, preferably, the Bim ligand is bis(1H-imidazol-1-yl)methane.

[0029] In the method described in this invention, preferably, the hydrothermal reaction is carried out under acidic conditions with a pH of 3-4.

[0030] In the method described in this invention, the pH of the reaction system is adjusted to 3-4 using a hydrochloric acid solution with a concentration of 0.5-1.5 mol / L. Preferably, the pH of the reaction system is adjusted to 3-4 using a hydrochloric acid solution with a concentration of 0.8-1.2 mol / L.

[0031] In the method described in this invention, the conditions for the hydrothermal reaction may include: a temperature of 150-180°C and a time of 80-120 hours. Preferably, the conditions for the hydrothermal reaction include: a temperature of 155-170°C and a time of 90-100 hours.

[0032] In the method described in this invention, the hydrothermal reaction can be carried out under stirring, and the stirring conditions may include: a stirring rate of 50-100 r / min and a time of 0.5-1.5 h. The hydrothermal reaction can be carried out in a stainless steel reactor.

[0033] In the method described in this invention, the hydrothermal reaction process may include: placing a metal salt of Co and / or Ni, borotungstic acid, and Bim ligand in a polytetrafluoroethylene liner, adding deionized water and stirring, adjusting the pH of the reaction system to 3-4 using hydrochloric acid solution, and then placing the liner in a reaction vessel for the reaction. After the reaction is complete, the mixture is cooled to room temperature and washed with deionized water.

[0034] This invention also provides the application of the above-mentioned polyacid-based metal-organic framework materials in the water adsorption process.

[0035] In practical applications, the polyacid-based metal-organic framework material described in this invention can capture water molecules in the air, evaporate and decompose the water molecules under heating conditions, and finally collect the liquid water through a condensation device.

[0036] The following examples further illustrate the polyacid-based metal-organic framework materials, their preparation methods, and applications according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0037] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0038] In the following examples and comparative examples, the parameters of the polyoxometalate metal-organic frameworks were tested according to the following methods: Water adsorption capacity test: A programmable temperature and humidity test chamber was used for the test. First, the mass of the weighing dish was recorded as m1. Then, the sample was weighed, placed in the weighing dish, and dried in an oven at 105℃ for 12 hours. The mass of the weighing dish containing the sample was recorded as m2. Finally, the dried sample was placed in the temperature and humidity test chamber and subjected to full adsorption at room temperature under five relative humidity conditions (30%, 50%, 70%, and 90%) for 10 hours. The mass of the sample after this period was recorded as m3. The formula for calculating the saturated adsorption capacity of the sample is as follows: W=(m3-m2) / (m2-m1) Determination of the crystal structure of polyacid groups: High-quality crystals were selected under a high-power microscope and fixed on an X-ray single-crystal diffractometer for data collection, with Mo-target Kα rays as the X-ray diffraction source. The crystal structure was analyzed using the SHELXL-2018 / 3 software package. The direct method was used to initially solve the crystal structure, and the data was refined using the least squares F2 method. Non-hydrogen atoms in the crystal structure were anisotropically refined, and hydrogenation was performed on C and N atoms using the theoretical hydrogenation method.

[0039] Infrared spectroscopy test: Grind the sample into powder, add a small amount of potassium bromide, press it into a round shape using a tablet press, and then place it in a Thermo Fisher Fourier transform infrared spectrometer for testing.

[0040] Example 1 Add 0.05g CoCl2·6H2O and 0.05g (H5BW) 12 O 4011.4H₂O and 0.025g of bis(1H-imidazol-1-yl)methane were placed in a polytetrafluoroethylene (PTFE) liner, and 10mL of deionized water was added and stirred for 1h. The pH of the reaction system was then adjusted using a 1mol / L hydrochloric acid solution, and the pH was measured to be 3.5. The PTFE liner was placed in a 25mL reactor, sealed, and reacted at 160℃ for 96h. After cooling to room temperature, the mixture was washed with deionized water. The resulting red, flaky crystals are the polyacid-based metal-organic framework material A1 of this invention.

[0041] The water adsorption capacity, polyacid-based metal-organic framework material A1 was tested, the polyacid-based crystal structure was determined, and infrared spectroscopy was performed. The test results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.25 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.32 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.25 g / g; The adsorption capacity is 2.51 g / g under 90% humidity conditions.

[0042] The XRD pattern of polyacid-based metal-organic framework material A1 is as follows: Figure 3 As shown.

[0043] The infrared spectrum of polyoxometallic framework material A1 is as follows: Figure 4 As shown.

[0044] Example 2 Add 0.05g NiCl2·6H2O and 0.05g (H5BW) 12 O 40 11.4H₂O and 0.025g of bis(1H-imidazol-1-yl)methane were placed in a polytetrafluoroethylene (PTFE) liner, and 10mL of deionized water was added and stirred for 1h. The pH of the reaction system was then adjusted using a 1mol / L hydrochloric acid solution, and the pH was measured to be 3.7. The PTFE liner was placed in a 25mL reactor, sealed, and reacted at 160℃ for 96h. After cooling to room temperature, the mixture was washed with deionized water, and the resulting green flaky crystals were the polyacid-based metal-organic framework material A2 of this invention.

[0045] The water adsorption capacity of polyacid-based metal-organic framework material A2 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.23 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.29 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.21 g / g; Under conditions of 90% humidity, the adsorption capacity is 2.49 g / g.

[0046] Example 3 Add 0.04g CoCl2·6H2O and 0.04g (H5BW) 12 O 40 11.4H₂O and 0.02g of bis(1H-imidazol-1-yl)methane were placed in a polytetrafluoroethylene (PTFE) liner, and 10mL of deionized water was added and stirred for 1h. The pH of the reaction system was then adjusted using 0.8mol / L hydrochloric acid solution, and the pH was measured to be 3.7. The PTFE liner was placed in a 25mL reactor, sealed, and reacted at 170℃ for 100h. After cooling to room temperature, the mixture was washed with deionized water. The resulting red, flaky crystals are the polyacid-based metal-organic framework material A3 of this invention.

[0047] The water adsorption capacity of polyacid-based metal-organic framework material A3 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.24 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.30 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.23 g / g; The adsorption capacity is 2.50 g / g under a humidity of 90%.

[0048] Example 4 Add 0.045g CoCl2·6H2O and 0.045g (H5BW) 12 O 40 11.4 H₂O and 0.03 g of bis(1H-imidazol-1-yl)methane were placed in a polytetrafluoroethylene (PTFE) liner, and 10 mL of deionized water was added and stirred for 1 h. The pH of the reaction system was then adjusted using a 1.2 mol / L hydrochloric acid solution, and the pH was measured to be 3.4. The PTFE liner was placed in a 25 mL reaction vessel, sealed, and reacted at 155 °C for 90 h. After cooling to room temperature, the mixture was washed with deionized water, and the resulting red, flaky crystals were the polyacid-based metal-organic framework material A4 of this invention.

[0049] The water adsorption capacity of polyacid-based metal-organic framework material A4 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.22 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.31 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.23 g / g; Under conditions of 90% humidity, the adsorption capacity is 2.49 g / g.

[0050] Example 5 Add 0.04g NiCl2·6H2O and 0.04g (H5BW) 12 O 40 11.4H₂O and 0.03g of bis(1H-imidazol-1-yl)methane were placed in a polytetrafluoroethylene (PTFE) liner, and 10mL of deionized water was added and stirred for 1h. The pH of the reaction system was then adjusted using 1.2mol / L hydrochloric acid solution, and the pH was measured to be 3.6. The PTFE liner was placed in a 25mL reactor, sealed, and reacted at 170℃ for 100h. After cooling to room temperature, the mixture was washed with deionized water. The resulting green, flaky crystals are the polyacid-based metal-organic framework material A5 of this invention.

[0051] The water adsorption capacity of polyacid-based metal-organic framework material A5 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.21 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.27 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.20 g / g; Under conditions of 90% humidity, the adsorption capacity is 2.47 g / g.

[0052] Example 6 Add 0.04g CoCl2·6H2O and 0.05g (H5BW) 12 O 40 11.4H₂O and 0.025g of bis(1H-imidazol-1-yl)methane were placed in a polytetrafluoroethylene (PTFE) liner, and 10mL of deionized water was added and stirred for 1h. The pH of the reaction system was then adjusted using a 1.0mol / L hydrochloric acid solution, and the pH was measured to be 3.5. The PTFE liner was placed in a 25mL reactor, sealed, and reacted at 165℃ for 100h. After cooling to room temperature, the mixture was washed with deionized water. The resulting red, flaky crystals are the polyacid-based metal-organic framework material A6 of this invention.

[0053] The water adsorption capacity of polyacid-based metal-organic framework material A6 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.23 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.29 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.21 g / g; The adsorption capacity is 2.48 g / g under 90% humidity conditions.

[0054] Example 7 Add 0.04g NiCl2·6H2O and 0.05g (H5BW) 12 O 40 11.4 H₂O and 0.025 g of bis(1H-imidazol-1-yl)methane were placed in a polytetrafluoroethylene (PTFE) liner, and 10 mL of deionized water was added. The mixture was stirred for 1 h, and the pH of the reaction system was adjusted using 0.9 mol / L hydrochloric acid solution. The pH of the reaction system was measured to be 3.4 using a pH meter. The PTFE liner was placed in a 25 mL reaction vessel, sealed, and reacted at 160 °C for 100 h. After cooling to room temperature, the mixture was washed with deionized water. The resulting green, flaky crystals are the polyacid-based metal-organic framework material A7 of this invention.

[0055] The water adsorption capacity of polyacid-based metal-organic framework material A7 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.22 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.26 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.20 g / g; Under conditions of 90% humidity, the adsorption capacity is 2.47 g / g.

[0056] Example 8 Add 0.05g NiCl2·6H2O and 0.04g (H5BW) 12 O 40 11.4H₂O and 0.03g of bis(1H-imidazol-1-yl)methane were placed in a polytetrafluoroethylene (PTFE) liner, and 10mL of deionized water was added and stirred for 1h. The pH of the reaction system was then adjusted using 0.8mol / L hydrochloric acid solution, and the pH was measured to be 3.5. The PTFE liner was placed in a 25mL reactor, sealed, and reacted at 155℃ for 90h. After cooling to room temperature, the mixture was washed with deionized water, and the resulting green flaky crystals were the polyacid-based metal-organic framework material A8 of this invention.

[0057] The water adsorption capacity of polyacid-based metal-organic framework material A8 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.24 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.28 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.22 g / g; Under conditions of 90% humidity, the adsorption capacity is 2.47 g / g.

[0058] Comparative Example 1 Polyacid-based metal-organic framework materials were prepared according to Example 1, except that CoCl2·6H2O was replaced with copper chloride, and no crystals were precipitated in the end.

[0059] Comparative Example 2 Polyacid-based metal-organic framework materials were prepared according to Example 1, except that CoCl2·6H2O was replaced with ferric chloride, and no crystals were precipitated in the end.

[0060] Comparative Example 3 Polyacid-based metal-organic framework materials were prepared according to Example 1, except that CoCl2·6H2O was replaced with ferric chloride, and no crystals were precipitated in the end.

[0061] Comparative Example 4 Polyacid-based metal-organic framework materials were prepared according to the method in Example 1, except that (H5BW) 12 O 40 When 11.4H2O is replaced with phosphotungstic acid, no crystals are precipitated.

[0062] Comparative Example 5 Polyacid-based metal-organic framework materials were prepared according to the method in Example 1, except that (H5BW) 12 O 40 When 11.4H2O was replaced with phosphomolybdic acid, no crystals were precipitated.

[0063] Comparative Example 6 Polyacid-based metal-organic framework materials were prepared according to Example 1, except that the pH of the reaction system was adjusted to 5.0, and polyacid-based metal-organic framework material D1 was finally prepared.

[0064] The water adsorption capacity of polyacid-based metal-organic framework material D1 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.18 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.24 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.14 g / g; Under conditions of 90% humidity, the adsorption capacity is 2.12 g / g.

[0065] Comparative Example 7 Polyacid-based metal-organic framework materials were prepared according to Example 1, except that the hydrothermal reaction temperature was 120°C, and polyacid-based metal-organic framework material D2 was finally obtained.

[0066] The water adsorption capacity of the polyacid-based metal-organic framework material D2 was tested, and the results are as follows: Under conditions of 30% humidity, the adsorption capacity is 0.16 g / g; Under conditions of 50% humidity, the adsorption capacity is 0.21 g / g; Under conditions of 70% humidity, the adsorption capacity is 1.12 g / g; Under conditions of 90% humidity, the adsorption capacity is 2.02 g / g.

[0067] The results of Examples 1-8 and Comparative Examples 1-7 are shown in Table 1 below.

[0068] Table 1

[0069] As can be seen from the results in Table 1, the polyacid-based metal-organic framework material prepared according to the method described in this invention has superior water absorption properties.

[0070] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polyacid-based metal-organic framework material, characterized in that, The chemical formula of this polyacid-based metal-organic framework material is M2(C7H8N4). n (HBW 12 O 40 )·mH2O, and the polyacid-based metal-organic framework material is a plate-like crystal, wherein M is Co and / or Ni, n is 1-6, and m is 3-10.

2. The polyacid-based metal-organic framework material of claim 1, wherein The crystal system of the polyacid-based metal organic framework material is triclinic, and the space group is P -1.

3. The polyacid-based metal-organic framework material of claim 1 or 2, wherein The chemical formula of the polyacid-based metal organic framework material is Co2(C7H8N4)4(HBW 12 O 40 )·4H2O and / or Ni2(C7H8N4)4(HBW 12 O 40 )·7H2O.

4. A method for producing the polyacidic metal-organic framework material according to any one of claims 1 to 3, characterized in that The method includes: carrying out a hydrothermal reaction of metal salts of Co and / or Ni, borotungstic acid, and Bim ligands in water under acidic conditions.

5. The method of claim 4, wherein, The mass ratio of the metal salt, the borotungstic acid, the Bim ligand, and water is (0.03-0.06):(0.03-0.06):(0.01-0.05):10, preferably (0.04-0.05):(0.04-0.05):(0.02-0.03):

10.

6. The method according to claim 4 or 5, characterized in that, The metal salt is nickel chloride and / or cobalt chloride.

7. The method according to claim 4 or 5, characterized in that, The Bim ligand is bis(1H-imidazol-1-yl)methane.

8. The method according to any one of claims 4-7, characterized in that, The hydrothermal reaction is carried out under acidic conditions with a pH of 3-4; Preferably, the pH of the reaction system is adjusted to 3-4 using a hydrochloric acid solution with a concentration of 0.5-1.5 mol / L.

9. The method according to any of claims 4-8, characterized by, The conditions for the hydrothermal reaction include: a temperature of 150-180℃ and a time of 80-120h.

10. The application of the polyacid-based metal-organic framework material according to any one of claims 1-3 in the water adsorption process.

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