Atmospheric water collection material

Abstract

The invention discloses an atmospheric water collection material. The nanofiber membrane comprises a hydrophilic nanofiber layer and a hydrophobic nanofiber layer which are laminated, wherein the hydrophilic nanofiber contains MOF. Compared with the prior art, the method has the advantages that the MOF is doped into the hydrophilic fiber of the asymmetric wettability Janus fiber membrane, so that the capability of capturing and adsorbing water molecules in the air of the material can be remarkably enhanced, and the atmospheric water collection efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of atmospheric water collection, and particularly relates to an atmospheric water collection material. BACKGROUND

[0002] With the increasingly serious global water resource shortage problem, it is particularly important to develop new water resource acquisition technologies. Atmospheric water collection technology, as an effective means of extracting water from air, shows broad application prospects in arid and semi-arid areas. Traditional water collection methods mainly rely on condensation or adsorption, but these methods are generally low in efficiency and are significantly affected by environmental humidity.

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

[0004] Metal-organic framework (MOF) material is a kind of crystalline porous material with periodic network structure formed by self-assembly of inorganic metal centers (metal ions or metal clusters) and bridged organic ligands. It has high specific surface area, adjustable pore structure, and excellent chemical stability and thermal stability. SUMMARY

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

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] An atmospheric water collection material comprises a hydrophilic nanofiber layer and a hydrophobic nanofiber layer stacked together, characterized in that the hydrophilic nanofiber contains MOF.

[0008] Preferably, the composition of the hydrophilic nanofiber consists of MOF, gelatin and polyvinyl alcohol, wherein the content of MOF is 5-15wt%, and the content of gelatin is 15-25wt%.

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

[0010] Preferably, the composition of the hydrophobic nanofiber is polyvinyl alcohol.

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

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

[0013] More preferably, the composition of the water-absorbing fiber bundle consists of MOF and gelatin, wherein the content of MOF is 20-40wt%.

[0014] More preferably, each of the water-absorbing fiber bundles is substantially parallel to each other, and the spacing is 5-10mm.

[0015] More preferably, the diameter of the water-absorbing fiber bundle is 1-5 microns.

[0016] Preferably, the MOF is MOF-303. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a preparation flowchart of the atmospheric water collecting material of the present application.

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

[0019] Figure 3 It is an infrared spectrum of the atmospheric water collecting material of the present application.

[0020] Figure 4 It is the moisture absorption performance of the atmospheric water collecting material of the present application under different humidity conditions.

[0021] Figure 5 It is the moisture absorption performance comparison of the atmospheric water collecting material of the present application and the existing atmospheric water collecting material.

[0022] Figure 6 It is the water retention performance of the atmospheric water collecting material of the present application.

[0023] Figure 7 It is the repeated swelling performance of the atmospheric water collecting material of the present application. DETAILED DESCRIPTION

[0024] The technical solutions of the present application are further described in detail below in combination with examples.

[0025] Example 1

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

[0027] (1) Preparation of hydrophilic nanofiber membrane layer: MOF-303 powder (CAS: 2050043-41-7), gelatin and PVA are mixed in a mass ratio of 1:2:7, added to deionized water, ultrasonic treatment for 1 hour, and then magnetic stirring for 12 hours to obtain a uniform spinning solution. Then the spinning solution is pushed to the spinneret at a stable speed, and electrospun in a high-voltage static electric field to obtain a hydrophilic nanofiber membrane 1 with a thickness of 1 mm.

[0028] (2) Pre-embedded water-absorbing fiber bundle: MOF-303 powder and gelatin are mixed in a mass ratio of 1:2, added to deionized water, ultrasonic treatment for 1 hour, and then magnetic stirring for 12 hours to obtain a uniform spinning solution. Then the spinning solution is pushed to the spinneret at a stable speed, and the hydrophilic nanofiber membrane substrate is reciprocated along the set deposition track to deposit several water-absorbing fiber bundles 2 with a diameter of 2 microns (single fiber diameter of 0.1-0.2 microns). The deposition tracks of the water-absorbing fiber bundles are approximately parallel to each other with a spacing of about 5 mm.

[0029] (3) Preparation of hydrophobic nanofiber membrane layer: PVA is added to deionized water, ultrasonic treatment for 1 hour, and then magnetic stirring for 12 hours to obtain a uniform spinning solution. Then the spinning solution is pushed to the spinneret at a stable speed, and a layer of hydrophobic nanofiber membrane 3 with a thickness of 1 mm is covered on the hydrophilic nanofiber membrane.

[0030] Comparative Example 1

[0031] The preparation process of the atmospheric water collection material comparative sample (Gelatin@NFM) is the same as that of Example 1, except that no MOF-303 powder is added during the preparation of the hydrophilic nanofiber membrane layer, and the mass ratio of gelatin to PVA is 2:7.

[0032] Figure 2 It is a scanning electron microscope (SEM) image of the hydrophilic layer of the atmospheric water collection material (Gelatin / MOF@NFM) of the application. From the SEM image, it can be observed that there are no free MOF particles in the hydrophilic nanofiber layer, indicating that the MOF has entered the fiber body.

[0033] Figure 3 It is an infrared spectrum (FTIR) of the atmospheric water collection material of the application, wherein curve a is MOF-303 material, curve b is Gelatin / MOF@NFM, and curve c is Gelatin@NFM.

[0034] Moisture absorption performance:

[0035] The experiment was carried out in a constant temperature and humidity experiment box. The material to be tested was placed in the experiment box with a pre-set humidity, and the moisture absorption rate was determined by weighing the test material after 12 hours of moisture absorption at room temperature.

[0036] Figure 4 The moisture absorption performance of the atmospheric water collection material of the present application under different humidity conditions. Among them, the specific experimental data of relative humidity 30%, 70%, 90% are shown in Table 1.

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

[0038] From the above experimental results, it can be seen that after introducing MOF into the hydrophilic nanofiber of Gelatin@NFM, a synergistic effect can be produced, thereby significantly improving the ability of the material to capture and adsorb water molecules in the air under different humidity environments.

[0039] Figure 5 The moisture absorption performance of the atmospheric water collection material of the present application and the existing atmospheric water collection material [1-6] is compared. It can be seen that the moisture absorption capacity of the atmospheric water collection material of the present application under different humidity conditions all exceeds that of the reported moisture absorption materials.

[0040] [1] SA-ZIF-8@SPI film: H. Liu, Xie W.-Y; Song F; Wang X.-L. and Wang Y.-Z; Chemical Engineering Journal 2019, 369, 1040-1048.

[0041] [2] HPCF: W. Chen, Zhang F; Yang Q; Yin C; Xiao T; Jiang L; Bai X; Tan X. and Lei Y; Langmuir 2025, 41 (27), 17369-17379.

[0042] [3] PET / EVA film: V.-T. Do and Chun D.-M; Colloids and Surfaces A: Physicochemical and Engineering Aspects 2023, 671, 131664.

[0043] [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.

[0044] [5] LBC@LiCl: W. Yao, Zhu X; Xu Z; Davis R. A; Liu G; Zhong H; Lin X; Dong P; Ye M. and Shen J; ACS Applied Materials & Interfaces 2022, 14 (3), 4680-4689.

[0045] [6] CA / PS blend electrospun fibers: S. Abosedira, Soliman M; Ebrahim S; Fadl E. and Khalil M; Alexandria Engineering Journal 2025, 111, 579-587.

[0046] Water retention performance:

[0047] The Gelatin / MOF@NFM material of the present application is placed in a constant temperature and humidity test box, and absorbs moisture for 12 hours at a relative humidity of 90% and room temperature. After the moisture absorption is completed, the material is placed in a constant temperature and humidity box with a temperature of 25±2°C and a relative humidity of 40%±5%, and then weighed and recorded every 1 hour to evaluate the water retention performance of the target object within 12 hours. As shown in Figure 6 , the atmospheric water collection material of the present application can effectively maintain and retain moisture for a long time.

[0048] Repetitive swelling performance:

[0049] The repetitive swelling performance of the Gelatin / MOF@NFM material of the present application is evaluated by a moisture absorption-desorption cycle experiment:

[0050] Moisture absorption: The material is placed in a constant temperature and humidity test box, and absorbs moisture for 12 hours at a relative humidity of 90% and room temperature, and the water absorption rate is determined.

[0051] Desorption: The material after moisture absorption is placed in a culture dish and covered with a smaller culture dish, and weighed every hour under sunlight. After desorption is completed (the weight basically does not change), the material is placed in a 70°C oven to dry the residual moisture.

[0052] As shown in Figure 7 , the water absorption rate of the atmospheric water collection material of the present application after 6 days of cycle operation can still reach more than 50% of the initial value, and has good repetitive swelling performance. This result fully proves that the high water absorption composite material has good recyclable and reusable performance, and can still maintain high water absorption capacity after multiple uses.

[0053] Example 2

[0054] The preparation of the atmospheric water collection material is the same as that of Example 1 (Gelatin / MOF@NFM), except that there is no water-absorbing fiber bundle between the hydrophilic nanofiber membrane layer and the hydrophobic nanofiber membrane layer.

[0055] Example 3

[0056] The preparation of the atmospheric water collection material is the same as that of Example 1 (Gelatin / MOF@NFM), except that the thickness of the hydrophilic nanofiber membrane layer is 2 mm, the spacing of the water-absorbing fiber bundle is 10 mm, and the thickness of the hydrophobic nanofiber membrane layer is 2 mm.

[0057] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application 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 replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An atmospheric water harvesting material comprising stacked layers of hydrophilic nanofibers and hydrophobic nanofibers, characterized in that: The hydrophilic nanofiber contains MOF.

2. The atmospheric water harvesting material of claim 1, wherein: The hydrophilic nanofiber is composed of MOF, gelatin and polyvinyl alcohol, wherein the content of MOF is 5-15wt%, and the content of gelatin is 15-25wt%.

3. The atmospheric water harvesting material of claim 2, wherein: The content of MOF is 10wt%, and the content of gelatin is 20wt%.

4. The atmospheric water harvesting material of claim 1, wherein: The hydrophobic nanofiber is composed of polyvinyl alcohol.

5. The atmospheric water harvesting material of claim 1, wherein: The thickness of the hydrophilic nanofiber layer is 1-2mm, and the thickness of the hydrophobic nanofiber layer is 1-2mm.

6. The atmospheric water harvesting material of claim 1, wherein: A plurality of water-absorbing fiber bundles are embedded between the hydrophilic nanofiber layer and the hydrophobic nanofiber layer.

7. The atmospheric water harvesting material of claim 6, wherein: The water-absorbing fiber bundle is composed of MOF and gelatin, wherein the content of MOF is 20-40wt%, and preferably, the mass ratio of MOF to gelatin is 1:

2.

8. The atmospheric water harvesting material of claim 6, wherein: Each of the water-absorbing fiber bundles is substantially parallel to each other, and the interval is 5-10mm.

9. The atmospheric water harvesting material of claim 6, wherein: The diameter of the water-absorbing fiber bundle is 1-5 microns.

10. The atmospheric water harvesting material of claim 1 or 7, wherein: The MOF is MOF-303.

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