MoS2 composite aerogel microsphere moisture absorption material and preparation method and application thereof

Abstract

The application discloses a kind of MoS2 Composite Aerogel Microbeads Moisture Absorption Material and its preparation method and application, its preparation method is: step 1: glycerol and acetylacetone molybdenum are dissolved in isopropyl alcohol / water solution, mix evenly to obtain transparent solution, the transparent solution is hydrothermal reaction, after reaction cooling, using ethanol washing, drying to obtain MoG powder;Step 2: MoG powder and thiourea are dissolved in ethanol / water solution, mix evenly to obtain brown solution, the brown solution is hydrothermal reaction, after reaction cooling, using ethanol washing, drying to obtain MoS2 powder;Step 3: MoS2 Powder is dissolved in acetic acid / water solution, after mixing, add chitosan powder, heat and mix evenly after solution cooling, drop into liquid nitrogen to form microbeads, after microbeads freeze-drying, immerse in sodium hydroxide / ethanol solution and solidify, then soak in calcium chloride solution, drying is obtained MoS2 Composite Aerogel Microbeads Moisture Absorption Material, its preparation method is simple, cost is lower, and moisture absorption performance is good.

Description

Technical Field

[0001] This invention belongs to the field of hydrogel technology, specifically relating to a MoS2 composite aerogel microsphere hygroscopic material, its preparation method, and its application. Background Technology

[0002] The Earth's atmosphere possesses a vast and renewable water resource, with 98% of atmospheric water existing in a gaseous state (vapor), and the remainder in a condensed state (clouds and fog). Atmospheric water harvesting (AWH) is primarily achieved through three methods: fog harvesting, dew harvesting, and adsorbent-based AWH. Fog harvesting, which uses vertical nets to capture small water droplets, is energy-efficient and low-cost, but requires persistently high relative humidity, thus often limiting its application to mountainous or coastal areas. Dew harvesting can operate at lower relative humidity and / or temperatures, but in these cases, refrigeration requires significant energy consumption to cool the air below the dew point. Therefore, existing dew systems are limited to areas with high relative humidity and temperature, while adsorbent-based AWH (Adsorption-Based Water Hydration) has a wide operating range. Adsorbent materials typically have a strong affinity for water, thus they can adsorb water vapor in both dry and humid environments. Furthermore, the water release process can utilize renewable energy sources, such as solar energy, for power. AWH can be well integrated with photothermal conversion technology, especially since arid and semi-arid regions often have abundant solar radiation. Therefore, by utilizing photothermal conversion technology to obtain solar energy and efficiently converting it, and combining it with AWH, the problem of freshwater shortage in arid and semi-arid regions can be alleviated, which has good application prospects. However, despite material advancements, problems such as low adsorption efficiency, small adsorption capacity, and the large amount of energy required for desorption limit the application of adsorbent-based AWH technology. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a method for preparing a MoS2 composite aerogel microsphere hygroscopic material, wherein the prepared MoS2 composite aerogel microsphere hygroscopic material has the advantages of high adsorption efficiency, large adsorption capacity, and low energy required for desorption.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing a MoS2 composite aerogel microsphere hygroscopic material, comprising the following steps:

[0005] Step 1: Dissolve glycerol and molybdenum acetylacetonate in isopropanol / water solution (water solution of isopropanol), mix well to obtain a transparent solution, carry out hydrothermal reaction of the transparent solution, cool after the reaction is completed, wash with ethanol, and dry to obtain MoG powder.

[0006] Step 2: Dissolve the MoG powder obtained in Step 1 and thiourea in an ethanol / water solution (an aqueous solution of ethanol), mix well to obtain a brown solution, carry out a hydrothermal reaction of the brown solution, cool after the reaction is completed, wash with ethanol, and dry to obtain MoS2 powder.

[0007] Step 3: Dissolve the MoS2 powder obtained in Step 2 in acetic acid / water solution (aqueous solution of acetic acid), mix well, add chitosan powder, heat and mix well, cool the solution to room temperature, drop it into liquid nitrogen to form microbeads, freeze-dry the microbeads, immerse them in sodium hydroxide / ethanol solution (solution formed by sodium hydroxide dissolved in ethanol) to solidify, immerse the solidified microbeads in calcium chloride solution, and then dry to obtain the MoS2 composite aerogel microbead moisture-absorbing material.

[0008] In the above technical solution, the volume-to-mass ratio of glycerol to molybdenum acetylacetonate in step 1 is 0.05-0.2 mL / mg, the volume ratio of isopropanol to water in the isopropanol / water solution is 3:1, and the volume ratio of glycerol to isopropanol / water solution is 0.2-1:1.

[0009] In step 2 of the above technical solution, the mass ratio of MoG powder to thiourea is 0.2-2:1, the volume ratio of ethanol to water in the ethanol / water solution is 3:1, and the mass-volume ratio of MoG powder to ethanol / water solution is 0.2-2 g / L.

[0010] In step 3 of the above technical solution, the mass ratio of chitosan to MoS2 powder is 2-20:1, the concentration of acetic acid / water solution is 5w / w%, the volume-mass ratio of its amount to the amount of chitosan is 10-50mL / g, the concentration of calcium chloride solution is 8wt%, and the volume ratio of its amount to the amount of acetic acid / water solution is 1-4:1.

[0011] In the above technical solution, the hydrothermal reactions in steps 1 and 2 are carried out in a stainless steel high-pressure reactor, and the reaction temperature is 150-220℃, and the reaction time is 1-10h.

[0012] In step 3 of the above technical solution, the heating temperature is 50-100℃, and the concentration of the sodium hydroxide / ethanol solution is 2 mol / L.

[0013] In the above technical solution, the drying process in steps 1 and 2 is vacuum drying, and the drying process in step 3 is freeze drying.

[0014] In the above technical solution, during the mixing process in steps 1, 2 and 3, ultrasonic dispersion is also performed simultaneously with stirring.

[0015] The second objective of this invention is to provide a MoS2 composite aerogel microsphere moisture-absorbing material with advantages such as high adsorption efficiency, large adsorption capacity, and low energy required for desorption.

[0016] To achieve the above objectives, the technical solution of the present invention is as follows: a MoS2 composite aerogel microsphere moisture-absorbing material, which is prepared by the method described above.

[0017] A third objective of this invention is to provide an application of the MoS2 composite aerogel microsphere hygroscopic material described above in air water extraction, moisture absorption irrigation, or photothermal conversion.

[0018] This invention has the following advantages and positive effects:

[0019] This invention uses molybdenum acetylacetonate as the molybdenum source and thiourea as the sulfur source to prepare MoS2 nanoflowers via a solvothermal method. These nanoflowers are then combined with calcium chloride, a hygroscopic salt, to prepare a hygroscopic gel. The preparation method is simple, low-cost, and exhibits good performance. This invention prepares the composite aerogel into a hollow, porous, bead-like structure, providing more contact sites between the hygroscopic salt and free water molecules in the air, as well as increasing the evaporation area, thereby improving the atmospheric water collection rate. This invention also uses MoS2 (molybdenum disulfide) to assist chitosan in constructing an adsorbent-based air humidifier (AWH), where chitosan... The raw materials are widely available and inexpensive, making them environmentally friendly. The molybdenum disulfide composite aerogel microsphere hygroscopic material prepared by this invention can be used for atmospheric water collection. By combining it with solar energy, it provides a sustainable green strategy for producing clean water and alleviating water scarcity. Under 1 sun light intensity, the surface temperature of the molybdenum disulfide composite aerogel microsphere hygroscopic material provided by this invention reaches a maximum of 41.6℃ after 30 minutes, and the water evaporation rate is 2.25 kg / m³ under 1 sun light intensity. -2 h -1 At 60% RH, its moisture absorption capacity is 0.70 g / L. -1 min -1 .

[0020] The mechanism is as follows: calcium chloride can be used to absorb moisture from the atmosphere (equivalent to absorbing moisture), and under sunlight, molybdenum disulfide has photothermal conversion properties, so it can raise the surface temperature of the hygroscopic material and release the absorbed moisture (desorption of absorbed moisture). During the desorption process, fresh water can be collected through condensation. Attached Figure Description

[0021] Figure 1 This is a SEM image of MoG in Embodiment 1 of the present invention;

[0022] Figure 2 Here is a SEM image of MoS2 in Embodiment 1 of the present invention;

[0023] Figure 3 This is a TEM image of MoS2 in Embodiment 1 of the present invention;

[0024] Figure 4 The image shown is an HRTEM image of MoS2 in Embodiment 1 of the present invention.

[0025] Figure 5 This is the EDS diagram of MoS2 in Embodiment 1 of the present invention;

[0026] Figure 6 The UV-Vis-NIR absorption spectra of MoS2 composite aerogel microspheres and blank aerogel microspheres in Example 1 of this invention are shown.

[0027] Figure 7 The MoS2 composite aerogel microspheres and blank aerogel microspheres in various embodiments of the present invention are at 1kW m -2 Surface temperature variation under solar radiation intensity;

[0028] Figure 8 The MoS2 composite aerogel microspheres and blank aerogel microspheres in various embodiments of the present invention are at 1kWm -2 Infrared image under solar radiation intensity;

[0029] Figure 9 The MoS2 composite aerogel microspheres and blank aerogel microspheres in various embodiments of the present invention are at 1kWm -2 A graph showing water evaporation under solar radiation intensity;

[0030] Figure 10 The graph shows the moisture absorption rate of MoS2 composite aerogel microspheres and blank aerogel microspheres in various embodiments of the present invention at 70% RH.

[0031] Figure 11 This is a graph showing the moisture absorption rate of MoS2 composite aerogel microspheres-1 under different humidity levels in Example 1 of the present invention.

[0032] Figure 12 This is a graph showing the evaporation rate, sample surface temperature, and ambient temperature of MoS2 composite aerogel microspheres-1 under different solar radiation intensities during an outdoor experiment in Example 1 of this invention.

[0033] Figure 13 This is a graph showing the moisture absorption rate and ambient temperature of MoS2 composite aerogel microspheres-1 in outdoor experiments under different humidity levels in Example 1 of this invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment provides a method for preparing a MoS2 composite aerogel microsphere hygroscopic material, including the following steps:

[0037] Step 1 (Preparation of MoG powder): Dissolve 8 mL of glycerol and 60 mg of molybdenum acetylacetonate in 20 mL of isopropanol / water mixed solution (volume ratio of isopropanol to water = 3:1), stir vigorously for 10 min, sonicate for 20 min, transfer the obtained uniform transparent solution to a stainless steel autoclave, react at 190 °C for 3 h, after the autoclave cools, wash three times with ethanol by centrifugation, and after washing, vacuum dry at 60 °C to obtain MoG powder;

[0038] Step 2 (Preparation of MoS2 powder): Dissolve 20 mg MoG powder and 40 mg thiourea in 40 mL of ethanol / water mixed solution (ethanol to water volume ratio = 3:1), stir for 10 min, sonicate for 20 min, transfer the obtained uniform brown solution to a stainless steel autoclave, react at 200 °C for 6 h, after the autoclave cools, wash three times with ethanol by centrifugation, and after washing, vacuum dry at 60 °C to obtain MoS2 powder;

[0039] Step 3 (Preparation of MoS2 composite aerogel microsphere hygroscopic material): Dissolve 0.25g MoS2 in 50mL of 5% (w / w) acetic acid / water mixed solution, ultrasonically stir for 10min, add 1.5g chitosan powder, stir at 60℃ for 20min, then ultrasonically for 15min. After the solution cools to room temperature, drop it into liquid nitrogen to form microspheres. After freeze-drying the microspheres, immerse them in 300mL of sodium hydroxide / ethanol solution (concentration 2mol / L) for curing, then soak them in 100mL of 8wt% calcium chloride solution, and freeze-dry for 48h to obtain MoS2 composite aerogel microsphere-1.

[0040] Example 2

[0041] Similar to Example 1, except that the amount of MoS2 powder used in step 3 is 0.15g, and the final product is MoS2 composite aerogel microspheres-2.

[0042] Example 3

[0043] Similar to Example 1, except that the amount of MoS2 powder used in step 3 is 0.125g, and the final product is MoS2 composite aerogel microspheres-3.

[0044] Example 4

[0045] Similar to Example 1, except that the amount of MoS2 powder used in step 3 is 0.1g, and the final product is MoS2 composite aerogel microspheres-4.

[0046] Blank example

[0047] 1.5 g of chitosan powder was dissolved in 50 mL of 5% (w / w) acetic acid / water solution, stirred at 60 °C for 20 min and sonicated for 15 min. After the solution was cooled to room temperature, it was dropped into liquid nitrogen to form microbeads. After freeze-drying, the microbeads were solidified by immersing them in 300 mL of 2 mol / L sodium hydroxide / ethanol solution. Then, they were immersed in 100 mL of 8 wt% calcium chloride solution and freeze-dried for 48 h to obtain blank aerogel microbeads.

[0048] Figure 1 and Figure 2 These are SEM images of MoG and MoS2 obtained in Embodiment 1 of the present invention. Figure 1 As can be seen, MoG has a uniform spherical structure with a diameter of 600 nm, is highly uniform, and has a smooth surface. Figure 2 As can be seen, the obtained MoS2 has a diameter of 600 nm and still maintains a uniform spherical structure similar to MoG nanospheres. Figure 1 and Figure 2 It clearly shows that 2D (two-dimensional) ultrathin sheet-like layers are uniformly grown on the outside of MoG nanospheres, thus MoS2 exhibits a nanoflower morphology.

[0049] Figure 3 and Figure 4 These are TEM and HRTEM images of MoS2 from Embodiment 1 of the present invention, respectively. Figure 4 As can be seen, MoS2 nanoflowers exhibit a distinct hollow microstructure, and from... Figure 3 It can be seen that the distribution of MoS2 nanoflowers exhibits good uniformity, with a diameter of approximately 600 nm.

[0050] Figure 5 This is an EDS image of MoS2 in Example 1 of the present invention. It confirms that the MoS2 nanoflowers contain the elements Mo, S, O, and C, with Mo and S being uniformly distributed. The elemental distribution is consistent with the morphological results of the MoS2 nanoflowers. The presence of the elements O and C may be due to the presence of carbon and oxygen elements in the preparation and testing environment of the MoS2 nanoflowers.

[0051] Figure 6 The images show the UV-Vis-NIR absorption spectra of MoS2 composite aerogel microsphere-1 and blank aerogel microsphere in Example 1 of this invention. The molybdenum disulfide composite aerogel microsphere has excellent light absorption in the solar radiation spectrum of 250-2000 nm, with an average solar light absorption rate as high as 95%.

[0052] Figure 7 The MoS2 composite aerogel microspheres and blank aerogel microspheres in various embodiments of the present invention are at 1kW m -2 Surface temperature variation under solar radiation intensity.

[0053] Figure 8 The MoS2 composite aerogel microspheres and blank aerogel microspheres in various embodiments of the present invention are at 1kW m -2 Infrared images under solar radiation intensity: Figure a shows the surface temperature of MoS2 composite aerogel microsphere-1; Figure b shows the surface temperature of MoS2 composite aerogel microsphere-2; Figure c shows the surface temperature of MoS2 composite aerogel microsphere-3; Figure d shows the surface temperature of MoS2 composite aerogel microsphere-4; Figure f shows the surface temperature of blank aerogel microspheres. As can be seen from the figures, the surface temperatures of both MoS2 composite aerogel microspheres and blank aerogel microspheres continuously increase with increasing testing time. At the same time interval, the surface temperature of MoS2 composite aerogel microsphere-1 is the highest, reaching 41.6℃, while the surface temperature of the blank aerogel microspheres is the lowest.

[0054] Figure 9 The MoS2 composite aerogel microspheres and blank aerogel microspheres in the various embodiments of the present invention are at 1kW m -2 The graph shows the water evaporation rate under solar radiation intensity. It can be seen from the graph that MoS2 composite aerogel microspheres-1 have a high water evaporation rate of 2.25 kg / m³. -2 h -1 .

[0055] Figure 10 The graph shows the moisture absorption rates of MoS2 composite aerogel microspheres and blank aerogel microspheres in various embodiments of the present invention at 70% RH. The graph shows that MoS2 composite aerogel microsphere-1 has a higher moisture absorption capacity.

[0056] Figure 11 This is a graph showing the moisture absorption rate of MoS2 composite aerogel microspheres-1 in Example 1 of the present invention under different humidity levels (40%RH, 50%RH, 60%RH, 70%RH). The moisture absorption capacity of MoS2 composite aerogel microspheres-1 continuously increases with increasing humidity.

[0057] Figure 12Images show the evaporation rate, sample surface temperature, and ambient temperature of MoS2 composite aerogel microspheres-1 under different solar radiation intensities during outdoor experiments in Example 1 of this invention. As can be seen from the images, the surface temperature of the MoS2 composite aerogel microspheres-1 changes with the intensity of sunlight, while the evaporation rate shows a stable upward trend, confirming that the MoS2 composite aerogel microspheres-1 possesses good evaporation capacity, with a maximum evaporation rate of 5.32 kg / m³. -2 h -1 .

[0058] Figure 13 Images show the moisture absorption rate of MoS2 composite aerogel microspheres-1 under different humidity levels and ambient temperatures in an outdoor experiment of Example 1 of this invention. The images show that the moisture absorption fluctuates with changes in sunlight intensity, but generally exhibits a stable upward trend, confirming that the MoS2 composite aerogel microspheres-1 possesses good moisture absorption capacity, with a maximum moisture absorption rate reaching 1.21 g / cm³. -1 .

[0059] As can be seen from Examples 1-7 above, this invention addresses the problems of low adsorption efficiency, small adsorption capacity, and large energy requirements for desorption in existing hygroscopic materials by focusing on their hygroscopic and evaporative properties. It provides a method for preparing and applying a hygroscopic material based on molybdenum disulfide composite aerogel microspheres. This invention utilizes CaCl2 as a hygroscopic agent and MoS2 to assist chitosan in forming a hollow, porous bead-like structure. This provides more contact sites between the hygroscopic salts and free water molecules in the air, as well as an evaporation area, thereby increasing the atmospheric water collection rate. By utilizing photothermal conversion technology to obtain solar energy and achieving efficient energy conversion, and by combining this with airborne heat and water (AWH) technology, it aims to alleviate freshwater shortages in arid and semi-arid regions, demonstrating promising application prospects.

[0060] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any changes, modifications, substitutions, combinations, or simplifications made based on the spirit and principle of the technical solutions of the present invention should be considered equivalent substitutions, and these changes should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a MoS2 composite aerogel microsphere hygroscopic material, characterized in that, Includes the following steps: Step 1: Dissolve glycerol and molybdenum acetylacetonate in a mixed solution of isopropanol / water, mix well to obtain a transparent solution, subject the transparent solution to a hydrothermal reaction, cool after the reaction is complete, wash with ethanol, and dry to obtain MoG powder; Step 2: Dissolve the MoG powder obtained in Step 1 and thiourea in an ethanol / water mixed solution, mix well to obtain a brown solution, carry out a hydrothermal reaction of the brown solution, cool after the reaction is completed, wash with ethanol, and dry to obtain MoS2 powder. Step 3: Dissolve the MoS2 powder obtained in Step 2 in an acetic acid / water mixed solution, mix well, add chitosan powder, heat and mix well, cool the solution to room temperature, drop it into liquid nitrogen to form microbeads, freeze-dry the microbeads, immerse them in a sodium hydroxide / ethanol mixed solution to solidify, immerse the solidified microbeads in a calcium chloride solution, and then dry them to obtain the MoS2 composite aerogel microbead moisture-absorbing material. The MoS2 composite aerogel microsphere moisture-absorbing material has a hollow, porous bead-like structure.

2. The method for preparing the MoS2 composite aerogel microsphere hygroscopic material according to claim 1, characterized in that, In step 1, the volume-to-mass ratio of glycerol to molybdenum acetylacetonate is 0.05-0.2 mL / mg, the volume ratio of isopropanol to water in the isopropanol / water mixed solution is 3:1, and the volume ratio of glycerol to the isopropanol / water mixed solution is 0.2-1:

1.

3. The method for preparing the MoS2 composite aerogel microsphere hygroscopic material according to claim 1, characterized in that, In step 2, the mass ratio of MoG powder to thiourea is 0.2-2:1, the volume ratio of ethanol to water in the ethanol / water mixed solution is 3:1, and the mass-volume ratio of MoG powder to the ethanol / water mixed solution is 0.2-2 g / L.

4. The method for preparing the MoS2 composite aerogel microsphere hygroscopic material according to claim 1, characterized in that, In step 3, the mass ratio of chitosan to MoS2 powder is 2-20:1, the concentration of the acetic acid / water mixed solution is 5 w / w, the volume-to-mass ratio of the amount of acetic acid / water mixed solution to the amount of chitosan is 10-50 mL / g, the concentration of the calcium chloride solution is 8 wt%, and the volume-to-volume ratio of the amount of calcium chloride solution to the amount of acetic acid / water mixed solution is 1-4:

1.

5. The method for preparing the MoS2 composite aerogel microsphere hygroscopic material according to claim 1, characterized in that, The hydrothermal reactions in steps 1 and 2 are carried out in a stainless steel autoclave at a temperature of 150-220°C for 1-10 hours.

6. The method for preparing the MoS2 composite aerogel microsphere hygroscopic material according to claim 1, characterized in that, In step 3, the heating temperature is 50-100℃, and the concentration of the sodium hydroxide / ethanol mixed solution is 2mol / L.

7. The method for preparing the MoS2 composite aerogel microsphere hygroscopic material according to claim 1, characterized in that, The drying process in steps 1 and 2 is vacuum drying, and the drying process in step 3 is freeze drying.

8. The method for preparing the MoS2 composite aerogel microsphere hygroscopic material according to claim 1, characterized in that, In the mixing process of steps 1 and 2, and in the mixing process of step 3, ultrasonic dispersion is performed simultaneously with stirring.

9. A MoS2 composite aerogel microsphere moisture-absorbing material, characterized in that, Prepared by the method described in any one of claims 1-8.

10. The application of the MoS2 composite aerogel microsphere hygroscopic material as described in claim 9 in air-to-water extraction.

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