An all-weather seawater desalination material, preparation method and application

Abstract

The present invention discloses an all-weather seawater desalination material, a preparation method and an application. The all-weather seawater desalination material comprises a first hydrophilic membrane layer, a hydrogel layer and a second hydrophilic membrane layer which are sequentially laminated from top to bottom. Among them, the first hydrophilic membrane layer is a fiber fabric with photothermal nanoparticles formed on the surface, the microcapsule phase change material is uniformly distributed in the hydrogel layer, and the second hydrophilic membrane layer is a fiber fabric or a fiber fabric with photothermal nanoparticles formed on the surface. The present invention uses a hydrogel material, a microcapsule phase change material and a fiber fabric with photothermal nanoparticles formed on the surface, which have excellent synergy, to form a material capable of realizing all-weather seawater desalination, and solves the technical problem of the strong dependence of the current water evaporation technology on sunlight.

Description

Technical Field

[0001] The present invention belongs to the technical field of seawater desalination materials, and more specifically, relates to an all-weather seawater desalination material, a preparation method and an application thereof. Background Art

[0002] With the development of social economy, the demand for energy by human beings is increasing. Due to the global energy shortage, sustainable and renewable environmental-friendly energy is favored by people. As the most promising sustainable renewable energy, solar energy occupies an important position in the energy field. Therefore, effectively utilizing solar energy is the key to solving the energy crisis and environmental pollution problems. At present, the ways of utilizing solar energy can be divided into three categories: photoelectric conversion, photochemical conversion and photothermal conversion. Among them, photothermal conversion, that is, converting light energy into heat energy, is the most direct and simplest and efficient way to use solar energy. Generating steam by using solar energy can directly convert the energy in sunlight into heat to promote the evaporation of water. Therefore, it has great application potential in energy conversion, seawater desalination, sewage treatment, liquid-liquid separation, disinfection and sanitation systems, etc. Excellent photothermal conversion materials can efficiently utilize solar energy, such as semiconductors, conjugated polymers, noble metal particles, and carbon materials, etc. However, on the one hand, the heat converted by the photothermal material during the day cannot be fully utilized, resulting in a certain waste. On the other hand, the characteristics of the sun rising in the east and setting in the west lead to the disadvantages of instability and intermittency in the utilization of solar energy, greatly reducing the utilization rate of solar energy. Therefore, safe and reliable energy storage technology is needed to support it.

[0003] Phase change materials release or absorb latent heat during the phase change process to cope with the change of environmental temperature, so as to achieve the regulation effect on the local environmental temperature. When the temperature is high, the phase change material absorbs heat and melts to store heat; when the external temperature drops, the phase change material releases heat and condenses to release heat, keeping the object temperature relatively stable. However, traditional phase change materials have problems such as leakage, phase separation and corrosion, which severely limit the use of such materials. Therefore, how to effectively utilize the heat storage and heat release performance of phase change materials and improve the efficiency of seawater desalination and sewage treatment has become an urgent problem to be solved at present. Summary of the Invention

[0004] Aiming at the above defects or improvement requirements of the prior art, the present invention provides an all-weather seawater desalination material, a preparation method and an application thereof. The purpose is to use a hydrogel material with excellent synergy, a microcapsule phase change material and a fiber fabric with photothermal nanoparticles formed on the surface to form a material capable of realizing all-weather seawater desalination, and solve the technical problem of the strong dependence of the current water evaporation technology on sunlight.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided an all-weather seawater desalination material, which is characterized in that it includes a first hydrophilic membrane layer, a hydrogel layer, and a second hydrophilic membrane layer that are sequentially laminated from top to bottom. Among them, the first hydrophilic membrane layer is a fiber fabric with photothermal nanoparticles formed on its surface, the microcapsule phase change material is uniformly distributed in the hydrogel layer, and the second hydrophilic membrane layer is a fiber fabric or a fiber fabric with photothermal nanoparticles formed on its surface.

[0006] Preferably, the microcapsule phase change material includes a core and a shell. The core is a phase change material, and the shell is a polymer wall material. The phase change material is an inorganic phase change material, an organic phase change material, or an organic-inorganic hybrid phase change material. The phase change temperature of the phase change material is 0°C - 80°C, and the mass ratio of the phase change material to the polymer wall material in the microcapsule phase change material is 3:7 to 7:3. Preferably, the particle size of the microcapsule phase change material is 1 - 200 μm.

[0007] Preferably, the thickness of the hydrogel layer is 2 μm - 20 mm, such as 10 μm, 20 μm, 40 μm, 100 μm, 500 μm, 1 mm, 5 mm, 10 mm, or 20 mm. Specifically, it can be made into coatings or specimens with different shapes and thicknesses according to the working conditions.

[0008] Preferably, the phase change material is at least one of paraffin, dodecane, pentadecane, hexadecane, methyl laurate, n-decanol, neopentyl glycol, or polyethylene glycol; the polymer wall material is at least one of polyethylene, polypropylene, melamine-formaldehyde, polysiloxane, polymethyl methacrylate, toluene diisocyanate, melamine resin, or polyurea.

[0009] Preferably, the matrix material of the hydrogel layer is a hydrophilic polymer material. Preferably, the matrix material of the hydrogel layer is at least one of polyvinyl alcohol, polyacrylic acid, gelatin, or sodium alginate.

[0010] Preferably, the photothermal nanoparticles are at least one of carbon nanotubes, graphene, carbon black, or light-absorbing materials. Among them, the light-absorbing materials are at least one of manganese dioxide, polypyrrole, or polydopamine; preferably, the thickness of the first hydrophilic membrane layer and the second hydrophilic membrane layer is 0.02 - 5 mm.

[0011] Preferably, the fiber fabric is a hydrophilic fabric, such as silk, cotton, linen, etc.; the fiber fabric includes any one of woven fabrics, knitted fabrics, and non-woven fabrics.

[0012] According to another aspect of the present invention, there is provided a preparation method for an all-weather seawater desalination material, including the following steps:

[0013] (1) After uniformly mixing the microcapsule phase change material, hydrophilic polymer material, crosslinking agent, and water, a crosslinking reaction occurs to obtain a hydrogel layer;

[0014] (2) By means of spraying or in-situ growth method, photothermal nanoparticles are formed on the fibrous fabric to obtain a first hydrophilic film layer and a second hydrophilic film layer;

[0015] (3) The first hydrophilic film layer and the second hydrophilic film layer are adhered to both sides of the hydrogel layer by pressing, and after standing, the all-weather seawater desalination material is obtained.

[0016] According to another aspect of the present invention, a method for preparing an all-weather seawater desalination material is provided, including the following steps:

[0017] (1) After uniformly mixing the microcapsule phase change material, hydrophilic polymer material, crosslinking agent, and water, a crosslinking reaction occurs to obtain a hydrogel layer;

[0018] (2) By means of spraying or in-situ growth method, photothermal nanoparticles are formed on the fibrous fabric to obtain a first hydrophilic film layer;

[0019] (3) The first hydrophilic film layer and the second hydrophilic film layer are adhered to both sides of the hydrogel layer by pressing, and after standing, the all-weather seawater desalination material is obtained, and the second hydrophilic film layer is a fibrous fabric.

[0020] Among them, the preparation process of the microcapsule phase change material is prior art, and it can be prepared by in-situ polymerization, interfacial polymerization method, interfacial polycondensation or sol-gel method.

[0021] Preferably, step (1) is: uniformly mixing 15 - 75 parts of hydrophilic polymer material, 25 - 75 parts of microcapsule phase change material, 1 - 35 parts of crosslinking agent, and 30 - 160 parts of water, then crosslinking and standing to obtain a hydrogel layer. Among them, the crosslinking agent is glutaraldehyde, hydrochloric acid, tannic acid or a photo-crosslinking agent.

[0022] Preferably, the temperature of the crosslinking reaction in step (1) is 5 - 50 °C, and the time of the crosslinking reaction is 1 minute - 1 hour.

[0023] According to still another aspect of the present invention, an application of an all-weather seawater desalination material is provided, for all-weather seawater desalination or sewage purification. The all-weather seawater desalination material is placed on polystyrene foam material, such that the second hydrophilic film layer is placed in water, and the first hydrophilic film and the hydrogel layer float on the water surface. The polystyrene foam has the functions of floating and heat insulation.

[0024] Generally speaking, compared with the prior art by the above technical solutions conceived by the present invention, at least the following beneficial effects can be achieved.

[0025] (1) The present invention uses a hydrogel material with excellent synergy, a microcapsule phase change material, and a fiber fabric with photothermal nanoparticles formed on its surface to form a photothermal material with a sandwich structure. Under strong sunlight, the heat converted by photothermal conversion is used for water evaporation and phase change energy storage; when sunlight is weak on cloudy days or in the evening, the phase change material releases heat to ensure continuous water evaporation, so that effective desalination of seawater or sewage treatment can be achieved throughout the day. In addition, the shaping effect of the hydrogel ensures a sufficient filling amount of the phase change material and the hydrophilicity of the intermediate layer, thus achieving excellent sunlight utilization efficiency and water evaporation rate.

[0026] (2) In the present invention, a polymer wall material is selected as the shell of the microcapsule phase change material. Since most polymer materials have poor hydrophilicity, the hydrophilicity and water transmission of the intermediate layer are realized by the hydrogel sandwiched between the microcapsules. The microcapsule phase change material can effectively prevent the leakage of the phase change material and the volume change caused by phase change, improving the internal temperature control and heat release stability of the material, and at the same time avoiding the blockage of the water transmission channel and the steam escape channel during the phase change process. When the temperature is high, the phase change material absorbs heat and stores the heat; when the external temperature drops, the phase change material releases heat to keep the object temperature relatively stable.

[0027] (3) In the present invention, the proportions of the components in the hydrogel layer are strictly controlled, and the crosslinking time is also strictly controlled, so that the hydrogel layer maintains a certain viscosity at a low crosslinking degree, thereby enabling the first hydrophilic film layer and the second hydrophilic film layer to be effectively adhered to the hydrogel layer without falling off.

[0028] (4) In the present invention, the second hydrophilic film layer can only use a fiber fabric. Since the second hydrophilic film layer comes into contact with water during application and plays a role in water conduction, the fiber fabric can meet the requirements of high water absorption performance. The second hydrophilic film layer can also use a fiber fabric with photothermal nanoparticles formed on its surface, and the advantage is that there is no need to distinguish which layer should be placed on the water surface during application. Description of the Drawings

[0029] Figure 1 It is a physical diagram of the all-weather seawater desalination material of Example 1 of the present invention;

[0030] Figure 2 In (a), it is a scanning electron microscope image of the photothermal fiber material of Example 2 of the present invention, Figure 2 In (b), it is Figure 2 a partial enlarged view of (a) in the figure;

[0031] Figure 3 In (a), it is a scanning electron microscope image of the hydrogel material of Example 3 of the present invention; Figure 3 In (b), it is Figure 3 a partial enlarged view of (a) in the figure;

[0032] Figure 4 DSC curve of the microcapsule phase change material prepared in Example 4 of the present invention;

[0033] Figure 5 For the all-weather seawater desalination material of Example 5 of the present invention compared with the traditional membrane material under 1 kW m -2 Heating-cooling curve under xenon lamp irradiation;

[0034] Figure 6 For the all-weather seawater desalination material of Example 6 of the present invention compared with the traditional membrane material under 1 kW m -2 Infrared thermal imaging photos at different times under xenon lamp irradiation;

[0035] Figure 7 For the all-weather seawater desalination material of Example 7 of the present invention under 1 kW m -2 Water mass loss diagram within 1 hour during the seawater desalination process under xenon lamp irradiation. Detailed implementation manners

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] Example 1

[0038] Using dodecanol as the core material and hexamethylene diisocyanate (HDI) and 1,3-propanediamine as the wall material monomers, phase change microcapsules were prepared by the interfacial polymerization method.

[0039] Mix 40 parts by weight of the microencapsulated phase change agent, 50 parts by weight of polyvinyl alcohol, 2 parts by weight of glutaraldehyde, 6 parts by weight of hydrochloric acid, and 80 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, crosslink at room temperature for 30 minutes, and demold to obtain a 10 mm thick hydrogel layer.

[0040] Immerse 2 g of fiber fabric in 30 mL of 1 mol L -1 Potassium permanganate solution, react for 15 minutes, rinse with water and ethanol, and then dry to obtain the manganese dioxide modified photothermal fiber material.

[0041] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and freeze-dry under vacuum to form the all-weather seawater desalination material.

[0042] Example 2

[0043] Using a 1:1 mixture of n-hexadecane and paraffin wax as the core material and polyurea as the wall material, phase change microcapsules were prepared by interfacial polymerization.

[0044] Mix 20 parts by weight of the microencapsulated phase change agent, 25 parts by weight of gelatin, 3 parts by weight of hydrochloric acid, and 80 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, crosslink at room temperature for 30 minutes, and demold to obtain a 5-mm-thick hydrogel layer.

[0045] Soak 2 g of the fiber fabric in 30 mL of 1 mol L -1 potassium permanganate solution, react for 30 minutes, rinse with water and ethanol, and then dry to obtain the manganese dioxide-modified photothermal fiber material.

[0046] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and vacuum freeze-dry to form the all-weather seawater desalination material.

[0047] From Figure 2 It can be seen from (a) and (b) that the manganese dioxide nanoparticles are evenly distributed on the fiber surface, increasing the light absorption and photothermal conversion performance of the fiber material.

[0048] Example 3

[0049] Using in-situ polymerization method, with n-octadecane as the core material, melamine resin as the wall material, and sodium dodecylbenzenesulfonate as the emulsifier, under high-speed emulsification, microcapsule phase change materials with smooth surface and uniform particle size were prepared.

[0050] Mix 60 parts by weight of the microcapsule phase change material, 75 parts by weight of polyvinyl alcohol, 3 parts by weight of glutaraldehyde, 9 parts by weight of hydrochloric acid, and 80 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, crosslink at room temperature for 30 minutes, and demold to obtain a 20-mm-thick hydrogel layer.

[0051] Soak 2 g of the fiber fabric in 30 mL of 1 mol L -1 potassium permanganate solution, react for 15 minutes, rinse with water and ethanol, and then dry to obtain the manganese dioxide-modified photothermal fiber material.

[0052] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and vacuum freeze-dry to form the all-weather seawater desalination material. From Figure 3 It can be seen from (a) and (b) that the 1-5 micron phase change microcapsules are evenly dispersed in the hydrogel material.

[0053] Example 4

[0054] Using paraffin wax as the core material and silica (SiO2) as the wall material, microencapsulated paraffin wax phase change agents were prepared by in-situ interfacial polycondensation method.

[0055] Mix 40 parts by weight of microencapsulated paraffin wax phase change agent, 50 parts by weight of polyvinyl alcohol, 2 parts by weight of glutaraldehyde, 6 parts by weight of hydrochloric acid, and 160 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, crosslink at room temperature for 30 minutes, and demold to obtain a 10-mm-thick hydrogel layer.

[0056] Mix 20 parts by weight of carbon nanotubes, 1 part by weight of glutaraldehyde, and 5 parts by weight of polyvinyl alcohol evenly, and ultrasonically disperse for 15 minutes. Then spray the obtained solution on the fiber fabric, and finally crosslink and fix it with 3 parts by weight of hydrochloric acid to obtain the photothermal fiber material.

[0057] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and vacuum freeze-dry to form the all-weather seawater desalination material. It can be seen from Figure 4 that the endothermic phase change temperature of the microcapsules is 38.34 °C, and the exothermic peak temperature is 32.35 °C.

[0058] Example 5

[0059] Using paraffin as the core material and the copolymer of styrene and methyl methacrylate as the wall material, prepare microencapsulated paraffin wax phase change agent by emulsion polymerization method.

[0060] Mix 40 parts by weight of microencapsulated paraffin wax phase change agent, 50 parts by weight of sodium alginate, 5 parts by weight of calcium chloride, and 80 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, crosslink at room temperature for 20 minutes, and demold to obtain a 10-mm-thick hydrogel layer.

[0061] Mix 20 parts by weight of polypyrrole, 1 part by weight of glutaraldehyde, and 5 parts by weight of polyvinyl alcohol evenly, and ultrasonically disperse for 15 minutes. Then spray the obtained solution on the fiber fabric, and finally crosslink and fix it with 3 parts by weight of hydrochloric acid to obtain the photothermal fiber material.

[0062] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and vacuum freeze-dry to form the all-weather seawater desalination material. It can be seen from Figure 5 that in this example, the photothermal + phase change composite material reaches the same temperature as the pure photothermal material under sunlight irradiation; after turning off the light, the exotherm of the phase change material causes the temperature of the composite material to decrease more slowly and shows a plateau.

[0063] Example 6

[0064] Using a 1:1 mixture of paraffin and n-octadecane as the core material and hexamethylene diisocyanate (HDI) and 1,3-propanediamine as the wall material monomers, prepare phase change microcapsules by interfacial polymerization method.

[0065] Mix 40 parts by weight of microcapsule paraffin wax phase change agent, 50 parts by weight of polyacrylic acid, and 80 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, and carry out photocrosslinking at room temperature for 10 minutes, then demold to obtain a hydrogel layer with a thickness of 10 mm.

[0066] Mix 20 parts by weight of polypyrrole, 1 part by weight of glutaraldehyde, and 5 parts by weight of polyvinyl alcohol evenly, and ultrasonically disperse for 15 minutes. Then spray the obtained solution on the fiber fabric, and finally crosslink and fix it with 3 parts by weight of hydrochloric acid to obtain the photothermal fiber material.

[0067] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and vacuum freeze-dry to form the all-weather seawater desalination material. Figure 6 It can be seen that within 60 minutes after turning on the light, the photothermal + phase change composite material and the pure photothermal material reach the same temperature; 10 minutes after turning off the light (i.e., at 70 minutes), the surface temperature of the photothermal + phase change composite material is 3 degrees Celsius higher than that of the pure photothermal material.

[0068] Example 7

[0069] Using n-octadecane as the core material and melamine-formaldehyde polymer as the shell material, synthesize phase change microcapsules by in-situ polymerization method.

[0070] First, mix 14.13 grams of melamine powder, 23.30 grams of formaldehyde solution (37 wt%), and 50 milliliters of deionized water in a three-necked flask. Adjust the pH value of the reaction system to 8.5 with triethanolamine, then keep the reaction at 70 °C and stir for 60 min to obtain melamine-formaldehyde prepolymer. Second, emulsify 230 grams of n-octadecane and 280 grams of sodium styrene-maleic anhydride copolymer solution (4.26 wt%) with a high-speed mixer at 9000 rpm and 60 °C for 45 min to obtain a stable and uniform emulsion. Adjust the pH value of the emulsion mixture to about 4.0 with citric acid. Then, under mechanical stirring, add the melamine-formaldehyde prepolymer dropwise to the prepared emulsion at a speed of 500 rpm for 30 minutes. After adding, raise the reaction temperature to 90 °C and keep it for 3 hours. Then cool the reaction mixture to room temperature to obtain the phase change microcapsule dispersion. Among them, the pH value of the mixture is adjusted to about 4.0 with citric acid. Then, under mechanical stirring, add the droplets to the prepared emulsion.

[0071] Mix 80 parts by weight of microencapsulated phase change agent, 100 parts by weight of polyvinyl alcohol, 4 parts by weight of glutaraldehyde, 10 parts by weight of hydrochloric acid, and 160 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, and crosslink at room temperature for 30 minutes, then demold to obtain a hydrogel layer with a thickness of 20 mm.

[0072] Soak 2 g of fibrous fabric in 30 parts by weight of pyrrole monomer solution, add 5 parts by weight of ferric chloride solution, react for 60 minutes, rinse with water and ethanol, and then dry to obtain the polypyrrole-modified photothermal fiber material.

[0073] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and then vacuum freeze-dry to form the all-weather seawater desalination material. Figure 7 It can be seen that under 1 sun illumination, the composite material can reach an evaporation rate of 2.7 kg m - 2 h -1 , which is 4.5 times that of pure water. After turning off the light, the composite material can still maintain an evaporation rate of 0.86 kg m -2 h -1 .

[0074] Example 8

[0075] Using a mixture of paraffin and dodecanol at a ratio of 3:1 as the core material and hexamethylene diisocyanate (HDI) and 1,3-propanediamine as the wall material monomers, phase change microcapsules were prepared by interfacial polymerization.

[0076] Mix 40 parts by weight of the microencapsulated phase change agent, 50 parts by weight of gelatin, 2 parts by weight of glutaraldehyde, 5 parts by weight of hydrochloric acid, and 80 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, crosslink at room temperature for 30 minutes, and demold to obtain a 10 mm thick hydrogel layer.

[0077] Mix 20 parts by weight of graphene, 1 part by weight of glutaraldehyde, and 5 parts by weight of polyvinyl alcohol evenly, and ultrasonically disperse for 15 minutes. Then spray the obtained solution on the fibrous fabric, and finally crosslink and fix it with 3 parts by weight of hydrochloric acid to obtain the photothermal fiber material.

[0078] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and then vacuum freeze-dry to form the all-weather seawater desalination material.

[0079] Example 9

[0080] Using a mixture of paraffin and dodecanol at a ratio of 1:1 as the core material and hexamethylene diisocyanate (HDI) and 1,3-propanediamine as the wall material monomers, phase change microcapsules were prepared by interfacial polymerization.

[0081] Mix 80 parts by weight of the microencapsulated phase change agent, 100 parts by weight of gelatin, 10 parts by weight of hydrochloric acid, and 160 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, crosslink at room temperature for 30 minutes, and demold to obtain a 20 mm thick hydrogel layer.

[0082] Mix 20 parts by weight of manganese dioxide, 1 part by weight of glutaraldehyde, and 5 parts by weight of polyvinyl alcohol evenly, and ultrasonically disperse for 15 minutes. Then spray the obtained solution on the fiber fabric, and finally crosslink and fix it with 3 parts by weight of hydrochloric acid to obtain the photothermal fiber material.

[0083] Gently press the prepared hydrophilic photothermal layer on both sides of the hydrogel material layer, let it stand, and vacuum freeze-dry to form the all-weather seawater desalination material.

[0084] Example 10

[0085] In this example, the all-weather seawater desalination material is prepared by the same method as in Example 1. The difference is that in this example, the hydrophilic photothermal layer serves as the first hydrophilic membrane layer, and the second hydrophilic membrane layer is only the fiber fabric.

[0086] Using dodecanol as the core material and hexamethylene diisocyanate (HDI) and 1,3-propanediamine as the wall material monomers, phase change microcapsules were prepared by interfacial polymerization.

[0087] Mix 40 parts by weight of the microencapsulated phase change agent, 50 parts by weight of polyvinyl alcohol, 2 parts by weight of glutaraldehyde, 6 parts by weight of hydrochloric acid, and 80 parts by weight of water evenly, put them into a cylindrical polytetrafluoroethylene mold, crosslink at room temperature for 30 minutes, and demold to obtain a 10-mm-thick hydrogel layer.

[0088] Immerse 2 g of the fiber fabric in 30 mL of 1 mol / L -1 potassium permanganate solution, react for 15 minutes, rinse with water and ethanol, and then dry to obtain the manganese dioxide-modified photothermal fiber material.

[0089] Gently press the prepared manganese dioxide-modified hydrophilic fiber photothermal layer and the unmodified hydrophilic fiber on both sides of the hydrogel material layer, let it stand, and vacuum freeze-dry to form the all-weather seawater desalination material.

[0090] Comparative Example 1

[0091] This comparative example prepares the all-weather seawater desalination material by the same method as in Example 1. The difference is that the crosslinking time is 2 hours. As time goes by, due to excessive crosslinking degree, it is impossible to bond the hydrophilic photothermal layer and the hydrogel material layer.

[0092] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An all-weather seawater desalination material, characterized in that, It includes a first hydrophilic membrane layer, a hydrogel layer, and a second hydrophilic membrane layer that are laminated in sequence from top to bottom. Among them, the first hydrophilic membrane layer is a fibrous fabric with photothermal nanoparticles formed on its surface. The hydrogel layer is uniformly distributed with microcapsule phase change materials. The second hydrophilic membrane layer is a fibrous fabric or a fibrous fabric with photothermal nanoparticles formed on its surface. The microcapsule phase change materials include a core and a shell. The core is a phase change material, and the shell is a polymer wall material. The polymer wall material is at least one of polyethylene, polypropylene, melamine-formaldehyde, polysiloxane, polymethyl methacrylate, toluene diisocyanate, melamine resin, or polyurea. After mixing 15-75 parts of a hydrophilic polymer material, 25-75 parts of microcapsule phase change materials, 1-35 parts of a crosslinking agent, and 30-160 parts of water evenly, crosslinking is carried out to obtain the hydrogel layer.

2. The all-weather seawater desalination material according to claim 1, characterized in that The phase change material is an inorganic phase change material, an organic phase change material, or an organic-inorganic hybrid phase change material. The phase change temperature of the phase change material is 0 °C - 80 °C. The mass ratio of the phase change material to the polymer wall material in the microcapsule phase change material is 3:7 to 7:

3.

3. The all-weather seawater desalination material according to claim 2, wherein The phase change material is at least one of paraffin, dodecane, pentadecane, hexadecane, methyl laurate, n-decanol, neopentyl glycol, or polyethylene glycol.

4. The all-weather seawater desalination material according to any one of claims 1-3, characterized in that, The matrix material of the hydrogel layer is a hydrophilic polymer material.

5. The all-weather seawater desalination material according to claim 4, characterized in that The hydrophilic polymer material is at least one of polyvinyl alcohol, polyacrylic acid, gelatin, or sodium alginate.

6. The all-weather seawater desalination material according to claim 1, wherein The photothermal nanoparticles are at least one of carbon nanotubes, graphene, carbon black, or light-absorbing materials. Among them, the light-absorbing materials are at least one of manganese dioxide, polypyrrole, or polydopamine. The fibrous fabric is a hydrophilic fabric.

7. The all-weather seawater desalination material according to claim 1, characterized in that, The thickness of the first hydrophilic membrane layer and the second hydrophilic membrane layer is 0.02 - 5 mm. The thickness of the hydrogel layer is 2 μm - 20 mm.

8. A method for preparing the all-weather seawater desalination material according to any one of claims 1-7, characterized in that, It includes the following steps: (1) After mixing the microcapsule phase change materials with the hydrophilic polymer material, the crosslinking agent, and water evenly, a crosslinking reaction occurs to obtain the hydrogel layer. (2) The photothermal nanoparticles are formed on the fibrous fabric by spraying or in-situ growth methods to obtain the first hydrophilic membrane layer and the second hydrophilic membrane layer. (3) The first hydrophilic membrane layer and the second hydrophilic membrane layer are laminated on both sides of the hydrogel layer by pressing, and after standing, the all-weather seawater desalination material is obtained.

9. A method for preparing the all-weather seawater desalination material according to any one of claims 1-7, characterized in that, It includes the following steps: (1) After mixing the microcapsule phase change materials with the hydrophilic polymer material, the crosslinking agent, and water evenly, a crosslinking reaction occurs to obtain the hydrogel layer. (2) The photothermal nanoparticles are formed on the fibrous fabric by spraying or in-situ growth methods to obtain the first hydrophilic membrane layer. (3) The first hydrophilic membrane layer and the second hydrophilic membrane layer are laminated on both sides of the hydrogel layer by pressing, and after standing, the all-weather seawater desalination material is obtained. The second hydrophilic membrane layer is a fibrous fabric.

10. The preparation method of the all-weather seawater desalination material according to claim 9, characterized in that, The crosslinking agent is glutaraldehyde, hydrochloric acid, tannic acid, or a photo-crosslinking agent.

11. The preparation method of the all-weather seawater desalination material according to claim 9, characterized in that, The temperature of the crosslinking reaction in step (1) is 5 - 50 °C, and the time of the crosslinking reaction is 1 minute - 1 hour.

12. Use of the all-weather seawater desalination material according to any one of claims 1-7, characterized in that, For all-weather seawater desalination or sewage purification, put the all-weather seawater desalination material into seawater or sewage and support it with foam material so that the second hydrophilic membrane layer is placed in water, and the intermediate layer and the first hydrophilic membrane layer float on the water surface.

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