Atmospheric water harvesting material

Abstract

The application discloses an atmospheric water collection material. It comprises a hydrophilic nanofiber layer and a hydrophobic nanofiber layer which are stacked, wherein the hydrophilic nanofiber contains MOF. Compared with the prior art, the application incorporates MOF into the hydrophilic fiber of the asymmetric wetting Janus fiber membrane, can significantly enhance the ability of such material to capture and adsorb water molecules in the air, and thus improves the atmospheric water collection efficiency.

Description

Technical Field

[0001] This invention belongs to the field of atmospheric water collection, and specifically relates to an atmospheric water collection material. Background Technology

[0002] Atmospheric water harvesting technology, as an effective means of extracting moisture from the air, shows broad application prospects in arid and semi-arid regions. Traditional water harvesting methods mainly rely on condensation or adsorption, but these methods are generally inefficient and significantly affected by ambient humidity.

[0003] Asymmetric wettability Janus fiber membrane is a membrane material with one hydrophobic side and the other hydrophilic side. Its unique transmembrane directional water transport function is widely used in oil-water separation, water mist collection and wearable patches.

[0004] Metal-organic framework (MOF) materials are a type of crystalline porous material with a periodic network structure, formed by the self-assembly of inorganic metal centers (metal ions or metal clusters) and bridging organic ligands. They have advantages such as high specific surface area, tunable pore structure, and excellent chemical and thermal stability. Summary of the Invention

[0005] The purpose of this invention is to improve the existing asymmetric wettability Janus fiber membrane by introducing MOF components into the hydrophilic fibers of its hydrophilic layer to enhance its ability to capture and adsorb water molecules in the air, thereby improving water collection efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An atmospheric water-collecting material, comprising a layered hydrophilic nanofiber layer and a hydrophobic nanofiber layer, characterized in that: the hydrophilic nanofibers contain MOF.

[0008] Preferably, the hydrophilic nanofibers are composed of MOF, gelatin and polyvinyl alcohol, wherein the content of MOF is 5-15 wt% and the content of gelatin is 15-25 wt%.

[0009] More preferably, the content of MOF is 10 wt% and the content of gelatin is 20 wt%.

[0010] Preferably, the hydrophobic nanofibers are composed of polyvinyl alcohol.

[0011] Preferably, the thickness of the hydrophilic nanofiber layer is 1-2 mm, and the thickness of the hydrophobic nanofiber layer is 1-2 mm.

[0012] Preferably, a plurality of water-absorbing fiber bundles are embedded between the hydrophilic nanofiber layer and the hydrophobic nanofiber layer.

[0013] More preferably, the absorbent fiber bundle is composed of MOF and gelatin, wherein the MOF content is 20-40 wt%. Most preferably, the mass ratio of MOF to gelatin is 1:2.

[0014] More preferably, each of the absorbent fiber bundles is substantially parallel to each other, with a spacing of 5~10mm.

[0015] More preferably, the diameter of the absorbent fiber bundle is 1 to 5 micrometers.

[0016] Preferably, the MOF is MOF-303. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the preparation process of the atmospheric water collection material of the present invention.

[0018] Figure 2 This is a scanning electron microscope image of the atmospheric water-collecting material (hydrophilic layer) of the present invention.

[0019] Figure 3 This is the infrared spectrum of the atmospheric water-collecting material of the present invention.

[0020] Figure 4 This invention demonstrates the moisture absorption properties of the atmospheric water collection material under different humidity conditions.

[0021] Figure 5 This invention provides a comparison of the moisture absorption properties of atmospheric water collection materials with those of existing atmospheric water collection materials.

[0022] Figure 6 This invention relates to the water retention performance of the atmospheric water collection material.

[0023] Figure 7 This invention relates to the repeated swelling performance of the atmospheric water collection material. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0025] Example 1

[0026] The atmospheric water-collecting material (Gelatin / MOF@NFM) of this invention is prepared using electrospinning technology. The electrospinning parameters are set as follows: temperature 25±2℃, humidity 30±5%, voltage 15kV, injection flow rate 1mL / h, and distance from the spinneret to the receiving device 15cm. The specific preparation process is as follows:

[0027] (1) Preparation of hydrophilic nanofiber membrane: MOF-303 powder (CAS: 2050043-41-7), gelatin and PVA were mixed at a mass ratio of 1:2:7, added to deionized water, ultrasonically treated for 1 hour, and then magnetically stirred for 12 hours to obtain a uniform spinning solution. The spinning solution was then pushed to the spinneret at a stable speed and electrospun under a high voltage electrostatic field to obtain a hydrophilic nanofiber membrane 1 with a thickness of 1 mm.

[0028] (2) Pre-embedded water-absorbing fiber bundles: MOF-303 powder and gelatin were mixed at a mass ratio of 1:2, added to deionized water, ultrasonically treated for 1 hour, and then magnetically stirred for 12 hours to obtain a uniform spinning solution. The spinning solution was then pushed to the spinneret at a stable speed and repeatedly spun along the set deposition track on the hydrophilic nanofiber membrane substrate (the diameter of a single filament is 0.1~0.2 micrometers) to deposit several water-absorbing fiber bundles 2 with a diameter of 2 micrometers. The deposition tracks of each water-absorbing fiber bundle are roughly parallel to each other, with a spacing of about 5 mm.

[0029] (3) Preparation of hydrophobic nanofiber membrane: PVA was added to deionized water, ultrasonically treated for 1 hour, and then magnetically stirred for 12 hours to obtain a uniform spinning solution. The spinning solution was then pushed to the spinneret at a stable speed to cover the hydrophilic nanofiber membrane with a hydrophobic nanofiber membrane 3 with a thickness of 1 mm.

[0030] Comparative Example 1

[0031] The preparation process of the atmospheric water collection material comparison sample (Gelatin@NFM) is the same as that in Example 1, except that MOF-303 powder is not added during the preparation of the hydrophilic nanofiber membrane, and the mass ratio of gelatin to PVA is 2:7.

[0032] Figure 2 This is a scanning electron microscope (SEM) image of the hydrophilic layer of the atmospheric water-collecting material (Gelatin / MOF@NFM) of this invention. The SEM image shows that no free MOF particles were observed in the hydrophilic nanofiber layer, indicating that the MOF has been incorporated into the fiber matrix.

[0033] Figure 3 The image shows the Fourier Transform Infrared (FTIR) spectrum of the atmospheric water collection material of this invention. Curve a represents MOF-303 material, curve b represents Gelatin / MOF@NFM, and curve c represents Gelatin@NFM.

[0034] Moisture absorption properties:

[0035] The experiment was conducted in a temperature and humidity controlled chamber. The material to be tested was placed in the chamber with a pre-set humidity level and allowed to absorb moisture at room temperature for 12 hours. The material was then weighed to determine its water absorption rate.

[0036] Figure 4 The moisture absorption performance of the atmospheric water-collecting material of this invention under different humidity conditions is shown in Table 1. Specific experimental data for relative humidity of 30%, 70%, and 90% are shown in Table 1.

[0037] Table 1. Water absorption rate of different materials under different humidity conditions

[0038]

[0039] The experimental results above show that introducing MOF into the hydrophilic nanofibers of Gelatin@NFM can produce a synergistic effect, thereby significantly improving the material's ability to capture and adsorb water molecules in the air under different humidity environments.

[0040] Figure 5 This paper compares the moisture absorption performance of the atmospheric water collection material of the present invention with that of existing atmospheric water collection materials [1-6]. It can be seen that the moisture absorption capacity of the atmospheric water collection material of the present invention exceeds that of the reported moisture-absorbing materials under different humidity conditions.

[0041] [1] SA-ZIF-8@SPI membrane: H. Liu, Xie W.-Y; Song F; Wang X.-L.and Wang Y.-Z; Chemical Engineering Journal 2019, 369, 1040-1048.

[0042] [2] HPCF:W. Chen, Zhang F;Yang Q;Yin C;Xiao T;Jiang L;Bai X;Tan X.andLei Y; Langmuir 2025, 41 (27), 17369-17379.

[0043] [3] PET / EVA film: V.-T.Doand Chun D.-M;

[0044] Colloids and Surfaces A: Physicochemical and Engineering Aspects 2023,671,131664.

[0045] [4] 0.07wt% ZrC nanofluid: J. Gao, Wang Z; Zhao X; Mahian O; Xie H. and Yu W; Energy Conversion and Management 2023, 297, 117750.

[0046] [5] LBC@LiCl: W. Yao, Zhu X; Xu Z; Davis R. A; Liu G; Zhong H; Lin

[0047] [6] CA / PS blended electrospun fibers: S. Abosedira, Soliman M; Ebrahim S; Fadl E. and Khalil M; Alexandria Engineering Journal 2025, 111, 579-587.

[0048] Water retention performance:

[0049] The Gelatin / MOF@NFM material of this invention was placed in a constant temperature and humidity chamber and allowed to absorb moisture for 12 hours at 90% relative humidity and room temperature. After moisture absorption, the material was placed in a constant temperature and humidity chamber at 25±2℃ and 40%±5% relative humidity, and its weight was recorded every hour to evaluate the water retention performance of the target material over 12 hours. Figure 6 As shown, the atmospheric water-collecting material of the present invention can effectively maintain and retain moisture for a relatively long period of time.

[0050] Repeated swelling performance:

[0051] The repeated swelling performance of the Gelatin / MOF@NFM material of this invention was evaluated by a moisture absorption-desorption cycle experiment:

[0052] Moisture absorption: The material is placed in a constant temperature and humidity test chamber and allowed to absorb moisture for 12 hours at a relative humidity of 90% and room temperature. The water absorption rate is then measured.

[0053] Desorption: Place the moisture-absorbing material in a petri dish and cover it with a smaller petri dish. Place it in the sun and weigh it every hour. After desorption is complete (the weight basically no longer changes), put the material in a 70℃ oven to dry the residual moisture.

[0054] like Figure 7 As shown, after 6 days of cyclic operation, the atmospheric water-collecting material of this invention still retains more than 50% of its initial water absorption rate, demonstrating excellent repeated swelling performance. This result fully proves that the superabsorbent composite material has good recyclability and can maintain a high water absorption capacity even after multiple uses.

[0055] Example 2

[0056] The preparation of the atmospheric water-collecting material is the same as in Example 1 (Gelatin / MOF@NFM), except that there are no water-absorbing fiber bundles between the hydrophilic nanofiber membrane layer and the hydrophobic nanofiber membrane layer.

[0057] Example 3

[0058] The preparation of the atmospheric water-collecting material is the same as in Example 1 (Gelatin / MOF@NFM), except that the thickness of the hydrophilic nanofiber membrane is 2 mm, the spacing of the water-absorbing fiber bundles is 10 mm, and the thickness of the hydrophobic nanofiber membrane is 2 mm.

[0059] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An atmospheric water-collecting material, comprising stacked hydrophilic nanofiber layers and hydrophobic nanofiber layers, characterized in that: The hydrophilic nanofibers contain MOF; The hydrophilic nanofibers are composed of MOF, gelatin, and polyvinyl alcohol, wherein the content of MOF is 5-15 wt% and the content of gelatin is 15-25 wt%. The hydrophobic nanofibers are composed of polyvinyl alcohol; A plurality of water-absorbing fiber bundles are embedded between the hydrophilic nanofiber layer and the hydrophobic nanofiber layer. The absorbent fiber bundle is composed of MOF and gelatin, wherein the content of MOF is 20~40 wt%; The absorbent fiber bundles are basically parallel to each other, with a spacing of 5~10mm; The diameter of the absorbent fiber bundle is 1~5 micrometers; The MOF mentioned is MOF-303.

2. The atmospheric water collection material according to claim 1, characterized in that: The hydrophilic nanofibers contain 10 wt% MOF and 20 wt% gelatin.

3. The atmospheric water collection material according to claim 1, characterized in that: The thickness of the hydrophilic nanofiber layer is 1~2 mm, and the thickness of the hydrophobic nanofiber layer is 1~2 mm.

4. The atmospheric water collection material according to claim 1, characterized in that: The absorbent fiber bundle is composed of MOF and gelatin in a mass ratio of 1:2.

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