Metal-organic framework materials capable of enriching water in dry air, their preparation and use
By synthesizing the metal-organic framework material ZPF-2-MX, the problem of low water absorption efficiency of porous materials under low humidity was solved, and efficient water collection and recycling in dry air was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANKAI UNIV
- Filing Date
- 2021-04-12
- Publication Date
- 2026-06-26
AI Technical Summary
Existing porous materials have low water absorption efficiency and require high energy consumption under low humidity conditions, making it difficult to effectively capture and transport water resources in the air.
A metal-organic framework material, ZPF-2-MX, was designed and synthesized. It can reversibly adsorb and desorb water vapor with divalent metal ions under low humidity by organic ligand 2-hydroxy-5-halogen pyrimidine, thereby achieving water enrichment by utilizing its high specific surface area and porous properties.
It achieves efficient water collection in dry air, has stable circulation performance and low-temperature adsorption and high-temperature release characteristics, and is suitable for reversible adsorption and desorption of water under low humidity conditions.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of inorganic functional materials, specifically relating to a class of metal-organic frameworks (MOFs), their synthesis methods, and applications. Background Technology
[0002] Two-thirds of the world's population faces water scarcity. However, water vapor and droplets in the atmosphere account for approximately 10% of global freshwater resources, including lakes, totaling over 130 trillion liters. Effective utilization of these resources could provide a significant solution to the water shortage problem. Currently, no effective method has been developed to capture and transport atmospheric water under low humidity conditions (below 30%). Theoretically, materials capable of absorbing and transferring atmospheric moisture using minimal energy (such as solar thermal energy) would be a promising candidate for water-absorbing devices.
[0003] Porous materials, such as zeolites, silica gel, and MOFs, can adsorb and capture moisture from air over a wide range of humidity levels. However, traditional adsorbents (such as zeolites and silica gel) either have low water absorption efficiency or require high energy consumption to release moisture. Although MOFs have been developed for many applications, including gas storage, separation and catalysis, energy conversion, and dehumidification, their use for water harvesting has only recently been proposed. The framework flexibility of MOFs, which allows them to be designed, prepared, and modified at the molecular level, coupled with their ultra-high porosity, makes them well-suited to address the aforementioned challenges.
[0004] Constructing porous framework materials capable of capturing water in the air is a major research topic, and there are very few precedents for constructing porous framework materials based on dry air conditions. This application addresses the shortcomings of traditional porous materials, such as low water absorption efficiency, high humidity requirements, and high energy consumption for water release. It creatively designs and synthesizes a class of metal-organic framework materials as water-capturing materials. Utilizing their reversible adsorption and desorption of water vapor, low operating humidity, high specific surface area, and porosity, a series of highly efficient water-collecting materials have been successfully synthesized. Summary of the Invention
[0005] The purpose of this invention is to provide a method for synthesizing metal-organic framework materials, and to creatively synthesize a class of metal-organic framework materials that can reversibly adsorb and desorb water vapor under low humidity, and apply them to enrich water in dry air.
[0006] On one hand, the present invention provides a class of metal-organic framework materials ZPF-2-MX, M=Zn / Co, X=F / Cl / Br / I, characterized in that it is obtained by coordination of the organic ligand 2-hydroxy-5-halogen pyrimidine and a divalent metal ion.
[0007] Preferably, the organic ligand 2-hydroxy-5-halogen pyrimidine is any one of (a) 2-hydroxy-5-fluoropyrimidine, (b) 2-hydroxy-5-chloropyrimidine, (c) 2-hydroxy-5-bromopyrimidine, and (d) 2-hydroxy-5-iodopyrimidine.
[0008] Preferably, the divalent metal ion is a zinc or cobalt ion.
[0009] On the other hand, the present invention provides a method for preparing the metal-organic framework material ZPF-2-MX, comprising the following steps:
[0010] 1) The organic ligand 2-hydroxy-5-halogen pyrimidine and divalent metal ions are added to water, and the pH is adjusted by deprotonation through an alkaline solution to carry out the reaction;
[0011] 2) After the reaction is complete, the product is separated and dried;
[0012] 3) The separated and dried products are heated under vacuum to obtain the final product.
[0013] Preferably, in the reaction solution, the molar ratio of divalent metal ions to the organic ligand 2-hydroxy-5-halogen pyrimidine is 1:(1-10), and more preferably 1:2.
[0014] Preferably, the initial concentration of the organic ligand 2-hydroxy-5-halogen pyrimidine in the reaction solution is 0.1-10 mol / L, more preferably 1-2 mol / L.
[0015] Preferably, the ion source of divalent metal ions in the reaction solution is any water-soluble salt such as nitrate, acetate, chloride, sulfate, and perchlorate.
[0016] Preferably, the alkaline solution is a sodium hydroxide, potassium hydroxide, or ammonium hydroxide solution.
[0017] Preferably, the concentration of the alkaline solution is 0.1-10 mol / L, more preferably 1-2 mol / L.
[0018] Preferably, the final pH of the solution is 4-11, more preferably 5-7.
[0019] Preferably, the synthesis temperature of the metal-organic framework is 0-50℃, with a preferred temperature of 20-30℃.
[0020] The technical solution adopted by the present invention to achieve the above-mentioned objective is as follows: adding the organic ligand 2-hydroxy-5-halogen pyrimidine and divalent metal ions to water, ultrasonically treating them to make them mix evenly, using an alkaline solution as a deprotonating agent, and adjusting the pH to 5-7 at 20-30℃ to obtain the product.
[0021] On the other hand, the metal-organic framework material ZPF-2-MX of the present invention can be used to enrich water in dry air.
[0022] Preferably, the relative humidity of the dry air is 5-30%.
[0023] Preferably, the metal-organic framework material obtained by the present invention has reversible water vapor adsorption and desorption properties. At low temperatures, it can absorb water vapor from dry air, while at high temperatures it can release it, thereby condensing and collecting it as liquid water. This process can be repeated multiple times.
[0024] Preferably, the mass of the metal-organic framework material used is 0.01-100g, more preferably 0.1-1g.
[0025] Preferably, the low temperature is 0-40℃, and more preferably 20-30℃.
[0026] Preferably, the high temperature is 50-150℃, more preferably 60-100℃.
[0027] Preferably, the low-temperature adsorption time is 1-200 min, more preferably 15-30 min.
[0028] Preferably, the high-temperature desorption time is 1-200 min, more preferably 15-30 min.
[0029] Preferably, the device used in the condensation process is a cold hydrazine or a commercial condenser.
[0030] Preferably, the number of cycle wheels is 2-100, more preferably 5-10.
[0031] Water collection tests in dry air show that the obtained metal-organic framework material ZPF-2-MX has stable water collection performance and stable recycling performance.
[0032] Preferably, the obtained metal-organic framework material ZPF-2-MX has reversible water vapor adsorption and desorption properties, low operating humidity, large specific surface area, and regular and adjustable pore structure, which is beneficial for collecting liquid water in dry air. Attached image description:
[0033] Figure 1 Schematic diagram of metal-organic framework material ZPF-2-MX and its water enrichment in dry air.
[0034] Figure 2 PXRD of metal-organic framework material ZPF-2-MX.
[0035] Figure 3Water vapor adsorption curve of metal-organic framework material ZPF-2-MX.
[0036] Figure 4 Average mass of liquid water obtained by enriching water in dry air using the metal-organic framework material ZPF-2-MX Detailed implementation method:
[0037] Unless otherwise stated in the context of this application, the technical terms and abbreviations used herein have the conventional meanings known to those skilled in the art; unless otherwise stated, the raw material compounds used in the following examples are all commercially available.
[0038] The synthesis and characterization of various properties of metal-organic framework materials as described in this invention are specifically implemented as follows. Conversely, the following examples are only for further explanation and illustration of this invention and should not be considered as limiting the scope of the invention, which will be limited only by the claims.
[0039] Examples 1-8 describe the synthesis method of metal-organic framework materials, and Examples 9-12 describe the water collection experiments in dry air to obtain metal-organic framework materials.
[0040] Example 1:
[0041] The synthesis of ZPF-2-Zn-F, a metal-organic framework material capable of accumulating water in dry air, is carried out through the following specific steps:
[0042] 2 mmol of the organic ligand 2-hydroxy-5-fluoropyrimidine and 1 mmol of zinc nitrate were added to 10 mL of water and sonicated until homogeneous. A 1 mol / L sodium hydroxide solution was used as a deprotonating agent. The reaction was carried out at 25 °C with the pH adjusted to 6 to obtain the white solid product ZPF-2-Zn-F. Its PXRD is shown below. Figure 2 As shown.
[0043] Example 2:
[0044] The synthesis of ZPF-2-Co-F, a metal-organic framework material capable of accumulating water in dry air, is carried out through the following specific steps:
[0045] 4 mmol of the organic ligand 2-hydroxy-5-fluoropyrimidine and 2 mmol of cobalt acetate were added to 10 mL of water and sonicated until homogeneous. A 1 mol / L sodium hydroxide solution was used as a deprotonating agent. The reaction was carried out at 25 °C with the pH adjusted to 7 to obtain the pink solid product ZPF-2-Co-F. Its PXRD is shown below. Figure 2 As shown.
[0046] Example 3:
[0047] The synthesis of ZPF-2-Zn-Cl, a metal-organic framework material capable of accumulating water in dry air, is carried out through the following specific steps:
[0048] 2 mmol of the organic ligand 2-hydroxy-5-chloropyrimidine and 1 mmol of zinc perchlorate were added to 10 mL of water and sonicated until homogeneous. A 1 mol / L potassium hydroxide solution was used as a deprotonating agent. The reaction was carried out at 25 °C with the pH adjusted to 5 to obtain the white solid product ZPF-2-Zn-Cl. Its PXRD is shown below. Figure 2 As shown.
[0049] Example 4:
[0050] The synthesis of ZPF-2-Co-Cl, a metal-organic framework material capable of accumulating water in dry air, is carried out through the following specific steps:
[0051] 4 mmol of the organic ligand 2-hydroxy-5-chloropyrimidine and 2 mmol of cobalt sulfate were added to 10 mL of water and sonicated until homogeneous. A 1 mol / L potassium hydroxide solution was used as a deprotonating agent. The reaction was carried out at 25 °C with the pH adjusted to 6 to obtain the pink solid product ZPF-2-Co-Cl. Its PXRD is shown below. Figure 2 As shown.
[0052] Example 5:
[0053] The synthesis of ZPF-2-Zn-Br, a metal-organic framework material capable of accumulating water in dry air, is carried out through the following specific steps:
[0054] 2 mmol of the organic ligand 2-hydroxy-5-bromopyrimidine and 1 mmol of zinc nitrate were added to 10 mL of water and sonicated until homogeneous. A 1 mol / L sodium hydroxide solution was used as a deprotonating agent. The reaction was carried out at 25 °C with the pH adjusted to 7 to obtain the white solid product ZPF-2-Zn-Br. Its PXRD is shown below. Figure 2 As shown.
[0055] Example 6:
[0056] The synthesis of ZPF-2-Co-Br, a metal-organic framework material capable of accumulating water in dry air, is carried out through the following specific steps:
[0057] 4 mmol of the organic ligand 2-hydroxy-5-bromopyrimidine and 2 mmol of cobalt acetate were added to 10 mL of water and sonicated until homogeneous. A 1 mol / L sodium hydroxide solution was used as a deprotonating agent. The reaction was carried out at 25 °C with the pH adjusted to 7 to obtain the pink solid product ZPF-2-Co-Br. Its PXRD is shown below. Figure 2 As shown.
[0058] Example 7:
[0059] The synthesis of ZPF-2-Zn-I, a metal-organic framework material capable of accumulating water in dry air, is carried out through the following specific steps:
[0060] 2 mmol of the organic ligand 2-hydroxy-5-iodopyrimidine and 1 mmol of zinc perchlorate were added to 10 mL of water and sonicated until homogeneous. A 1 mol / L sodium hydroxide solution was used as a deprotonating agent. The reaction was carried out at 25 °C with the pH adjusted to 5 to obtain the white solid product ZPF-2-Zn-I. Its PXRD is as follows: Figure 2 As shown.
[0061] Example 8:
[0062] The synthesis of ZPF-2-Co-I, a metal-organic framework material capable of accumulating water in dry air, is carried out through the following specific steps:
[0063] 4 mmol of the organic ligand 2-hydroxy-5-iodopyrimidine and 2 mmol of cobalt sulfate were added to 10 mL of water and sonicated until homogeneous. A 1 mol / L sodium hydroxide solution was used as a deprotonating agent. The reaction was carried out at 25 °C with the pH adjusted to 6 to obtain the pink solid product ZPF-2-Co-I. Its PXRD is shown below. Figure 2 As shown.
[0064] Example 9:
[0065] 0.5 g of ZPF-2-Zn-F powder was weighed and placed in an environment of 25℃ and 20% humidity to absorb water vapor from the air for 30 min. The adsorbed water vapor was then released at 80℃ for 30 min, and collected using cold hydrazine to obtain liquid water. This process was repeated 5 times. The average mass of the obtained liquid water is shown in the figure. Figure 4 .
[0066] Example 10:
[0067] 1 g of ZPF-2-Co-F powder was weighed and placed in an environment of 25℃ and 15% humidity to absorb water vapor from the air for 60 min. Then, the adsorbed water vapor was released at 100℃ for 15 min, and collected using cold hydrazine to obtain liquid water. This process was repeated 7 times. The average mass of the obtained liquid water is shown in the figure. Figure 4 .
[0068] Example 11:
[0069] 0.1 g of ZPF-2-Zn-Cl powder was weighed and placed in an environment of 25℃ and 25% humidity to absorb water vapor from the air for 20 min. The adsorbed water vapor was then released at 60℃ for 60 min, and collected using cold hydrazine to obtain liquid water. This process was repeated 10 times. The average mass of the obtained liquid water is shown in the figure. Figure 4 .
[0070] Example 12:
[0071] 0.8 g of ZPF-2-Co-Cl powder was weighed and placed in an environment of 25℃ and 30% humidity to absorb water vapor from the air for 40 min. The adsorbed water vapor was then released at 90℃ for 40 min, and collected using cold hydrazine to obtain liquid water. This process was repeated 8 times. The average mass of the obtained liquid water is shown in the figure. Figure 4 .
Claims
1. The application of a class of metal-organic framework materials capable of reversibly adsorbing and desorbing water vapor at low humidity, said metal-organic framework material being obtained by coordination of an organic ligand 2-hydroxy-5-halogen pyrimidine with a divalent metal ion, wherein the divalent metal ion is a zinc or cobalt ion, characterized in that, The metal-organic framework material is used to enrich water in dry air with a relative humidity of 5-30%.
2. The use of the metal-organic framework material according to claim 1, characterized in that, The organic ligand 2-hydroxy-5-halogen pyrimidine is any one of (a) 2-hydroxy-5-fluoropyrimidine, (b) 2-hydroxy-5-chloropyrimidine, (c) 2-hydroxy-5-bromopyrimidine, and (d) 2-hydroxy-5-iodopyrimidine.
3. An application of the metal-organic framework material according to any one of claims 1-2, characterized in that, The method for preparing the metal-organic framework described herein includes the following steps: 1) The organic ligand 2-hydroxy-5-halogen pyrimidine and divalent metal ions are added to water, and the pH is adjusted by deprotonation through an alkaline solution to carry out the reaction; 2) After the reaction is complete, the product is centrifuged and dried; 3) The product after centrifugation and drying is heated under vacuum to obtain the final product.
4. The application according to claim 3, characterized in that, In preparation step 1), the molar ratio of divalent metal ions to the organic ligand 2-hydroxy-5-halogen pyrimidine is 1:(1-10).
5. The application according to claim 3, characterized in that, In step 1), the initial concentration of the organic ligand 2-hydroxy-5-halogen pyrimidine in the reaction solution is 0.1-10 mol / L.
6. The application according to claim 3, characterized in that, In preparation step 1), the ion source for divalent metal ions is its nitrate, acetate, chloride, sulfate, or perchlorate.
7. The application according to claim 3, characterized in that, In preparation step 1), the alkaline solution is a sodium hydroxide, potassium hydroxide, or ammonium hydroxide solution.
8. The application according to claim 3, characterized in that, The concentration of the alkaline solution in preparation step 1) is 0.1-10 mol / L.
9. The application according to claim 3, characterized in that, The final pH of the solution in preparation step 1) is 4-11.
10. The application according to claim 3, characterized in that, The synthesis temperature of the metal-organic framework in preparation step 1) is 0-50℃.