Confinement water-based high-efficiency photothermal evaporation material and device

Abstract

The application provides a confined water type high-efficiency photothermal evaporation material and device, which comprises a nanopore photothermal conversion material layer and a hydrophilic material filled in the nanopore to form a high-water-absorption confined evaporation structure. The hydrophilic material is preferably filled into the nanopore by an atomic layer deposition method, and the hydrophobic material layer is preferably obtained by photothermal conversion nanoparticle suspension immersion coating or spraying. The application forms a high-water-absorption confined evaporation structure by constructing a nanopore photothermal conversion material layer and filling a hydrophilic material in the nanopore, changes the evaporation form of water molecules in the confined space, reduces the evaporation enthalpy, thereby significantly improves the evaporation rate and the photothermal conversion efficiency, greatly improves the solar energy conversion capacity, saves the manufacturing cost and the energy consumption cost, and is applicable to micro devices and has higher universality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photothermal evaporation material preparation, and particularly relates to a confined water type efficient photothermal evaporation material and device. BACKGROUND

[0002] The photothermal evaporation material can obtain fresh water by using solar energy to heat evaporation. The technology does not consume other traditional power sources and heat sources, is environmentally friendly and clean, and can reduce the energy consumption cost of the evaporation system, and gradually attracts people's attention.

[0003] The photothermal evaporation material generally comprises a water absorption unit and a photothermal conversion evaporation unit. The water absorption unit promotes the transportation of water at the interface to the photothermal conversion unit. The photothermal conversion unit converts solar energy into heat energy to promote water evaporation, and obtains treated clean water resources. Therefore, the structure of the photothermal evaporation material has an important influence on the photothermal evaporation rate. By regulating the structure of the water absorption unit and the photothermal conversion evaporation unit, the photothermal conversion efficiency can be regulated, thereby significantly improving the industrial application value.

[0004] For the interface evaporation model, in the case of only solar energy input, due to the latent heat requirement of water evaporation, the water vapor production rate of the two-dimensional interface photothermal evaporation interface under one-time solar irradiation (1 kW / m 2 ) will be limited to 1.47 kg m -2 h -1 (assuming an energy conversion efficiency of 100%). Most of the methods today are to introduce wind energy, electric energy, convection and other external energy sources other than solar energy to improve the evaporation rate, which relatively increases the energy consumption. Or by constructing a three-dimensional photothermal evaporation material, the content of the photothermal conversion material per unit area is increased, thereby improving the photothermal evaporation rate. This method increases the manufacturing cost and is not suitable for some small device fields.

[0005] Patent CN202210214827.7 discloses a cattail-based light-heat interface evaporation material and its preparation method and application. The cattail is carbonized in a tube furnace to obtain carbon powder. The cattail is added to a reaction kettle, and sodium hydroxide is added to react to obtain cattail leaf cellulose. The cattail leaf cellulose is added to a container, and water and carbon powder are added. After filtration, a cattail-based light-heat film is obtained. When used, the cattail leaves can be bundled as a water guide material, and the cattail-based light-heat film is placed on it to form an interface evaporation device. The light-heat conversion cattail-based light-heat film constructs a three-dimensional pore structure through cattail leaf cellulose and carbon powder dispersion liquid, has strong hydrophilicity and water guiding ability, and has good light absorption. At the same time, the cattail leaves are used as hydrophilic and water guiding materials to improve the water evaporation efficiency and salt resistance. However, the light-heat interface evaporation material needs special raw material sources to have good water absorption and light-heat conversion performance, which has certain limitations, and the energy conversion efficiency needs to be further improved. Therefore, it is necessary to design an improved limited water type high-efficiency light-heat evaporation material and device to solve the above problems. SUMMARY

[0006] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a limited water type high-efficiency light-heat evaporation material and device, by constructing a nano-pore light-heat conversion material layer and filling a hydrophilic material in the nano-pore, forming a high water absorption limited evaporation structure, so that the evaporation form of water molecules in the limited space changes, the evaporation enthalpy is reduced, thereby significantly improving the evaporation rate and light-heat conversion efficiency, greatly improving the solar energy conversion ability, saving the manufacturing cost and energy consumption cost, and being applicable to micro devices, having higher universality.

[0007] In order to achieve the above-mentioned purpose of the application, the present application provides a limited water type high-efficiency light-heat evaporation material, comprising a nano-pore light-heat conversion material layer and a hydrophilic material filled in the nano-pore, to form a high water absorption limited evaporation structure.

[0008] As a further improvement of the present application, the thickness of the nano-pore light-heat conversion material layer is 50-200 nm, preferably 80-120 nm; the pore size of the nano-pore is 3-60 nm, preferably 5-20 nm.

[0009] As a further improvement of the present application, the outside of the nano-pore light-heat conversion material layer is not deposited with the hydrophilic material.

[0010] As a further improvement of the present application, the nano-pore light-heat conversion material layer is obtained by dip coating or spray coating of a light-heat conversion nanoparticle suspension, and the nano-pore is a pore formed between the light-heat conversion nanoparticles.

[0011] As a further improvement of the present application, the photo-thermal conversion nanoparticles are hydrophobic photo-thermal conversion nanoparticles, including one or more of zirconium carbide, graphene, carbon nanotubes; the hydrophilic material is a hydrophilic inorganic oxide or an organic material containing one or more of carboxyl, sulfonate, hydroxyl, amino, quaternary ammonium salt.

[0012] As a further improvement of the present application, the hydrophilic inorganic oxide includes one or more of titanium dioxide, aluminum oxide, silicon dioxide; the organic material includes one or more of acrylic acid.

[0013] As a further improvement of the present application, the hydrophilic material is filled into the nanopores by an atomic layer deposition method.

[0014] As a further improvement of the present application, a nanopore photo-thermal conversion material layer is prepared, and then the hydrophilic material is embedded into the nanopores of the photo-thermal conversion material layer by adjusting the number of cycles of atomic layer deposition, so as to adjust the number of confined spaces.

[0015] As a further improvement of the present application, the confined water type high-efficiency photo-thermal evaporation material further includes a hydrophilic substrate, which is obtained by dip coating or spray coating the hydrophobic nanoparticle suspension onto the surface of the hydrophilic substrate; the hydrophilic substrate is preferably a fiber-based hydrophilic substrate, and the material includes one or more of cotton, cellulose, and polyamide.

[0016] A confined water type high-efficiency photo-thermal evaporation device is prepared by using any one of the confined water type high-efficiency photo-thermal evaporation materials described above.

[0017] The present application has the following advantages:

[0018] 1. The confined water type high-efficiency photo-thermal evaporation material provided by the present application forms a high water-absorbing confined evaporation structure by constructing a nanopore photo-thermal conversion material layer and filling a hydrophilic material into the nanopores, so that the evaporation form of water molecules in the confined space changes, the evaporation enthalpy is reduced, and the evaporation rate and photo-thermal conversion efficiency are significantly improved. The present application can be designed in a two-dimensional layer, forming a micro-nano confined space, and the water evaporation amount per unit area is significantly improved, and the utilization rate of photo-thermal conversion material is also improved, so that the manufacturing cost and energy consumption cost are significantly reduced.

[0019] 2. The present application can use photo-thermal conversion nanoparticles to construct a nanopore photo-thermal conversion material layer by a dip coating or spray coating method, so that nanopores are formed between the nanoparticles, and then filled by gas phase deposition. The preparation method is simple, and breaks the limitation of confined structure materials, providing a new preparation method and idea for improving the evaporation rate based on the nano structure for reducing the evaporation enthalpy, and significantly expanding the types of available materials.

[0020] 3. Existing methods for constructing confined spaces often involve building them in three dimensions, with few methods focusing on constructing confined spaces in a two-dimensional plane. This invention utilizes atomic layer deposition (ALD), a method that can prepare atomic thin films suitable for various interfaces at low temperatures and allows for precise control of film thickness. Combined with hydrophobic nanomaterials, this method constructs confined spaces on flexible substrate surfaces, significantly expanding the preparation pathways for such materials and simplifying the preparation process. This has significant implications for the field of photothermal evaporation water treatment.

[0021] 4. By embedding hydrophilic materials into nanopores, this invention not only constructs a confined water space with high water absorption, but also improves the stability and load strength of photothermal conversion nanoparticles through the binding effect of nanopores. Thus, multiple benefits are achieved through a simple preparation method without the need for complicated chemical modification, and therefore it has high versatility. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the confined water-based high-efficiency photothermal evaporation material of the present invention.

[0023] Figure 2 This is a high-resolution transmission electron microscope image of the confined water-based high-efficiency photothermal evaporation material of the present invention.

[0024] Figure 3 The mass loss curve of the confined water-based high-efficiency photothermal evaporation material prepared in Example 1 under one sun in pure water.

[0025] Figure 4 The change in enthalpy of evaporation of water in the confined water-based high-efficiency photothermal evaporation material prepared in Example 1 is shown in relation to the number of cycles of titanium dioxide atomic layer deposition. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to specific embodiments.

[0027] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the specific embodiments, while other details that are not closely related to the present invention are omitted.

[0028] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] Please see Figure 1As shown, the application provides a limited water type high-efficiency photothermal evaporation material, which comprises a nano-pore photothermal conversion material layer and a hydrophilic material filled in the nano-pore to form a high water absorption limited evaporation structure. In this way, when used for interface photothermal evaporation, water molecules are quickly absorbed and bound by the hydrophilic material in the nano-pore, forming a limited water nano effect, so that the water evaporation enthalpy is significantly reduced and is more easily evaporated; at the same time, the surrounding photothermal conversion material absorbs solar energy to convert into heat, thereby promoting the evaporation of water in the nano-pore, realizing interface water purification treatment. The application can be designed on a two-dimensional level to form a micro-nano limited space, the water evaporation amount per unit area is significantly increased, and the utilization rate of the photothermal conversion material is increased, so that the manufacturing cost and energy consumption cost are significantly reduced.

[0030] Preferably, the application selects photothermal conversion nanoparticles to construct the nano-pore photothermal conversion material layer, for example, which can be obtained by dipping or spraying a photothermal conversion nanoparticle suspension, and the photothermal conversion nanoparticles form the nano-pores between the nanoparticles. In this way, compared with the prior art which needs to use materials with specific pore structures, the range of selectable materials for the photothermal conversion material layer is significantly expanded, the preparation method is simple and easy to operate, the material thickness can reach the nanometer level, and it is convenient to construct a limited structure film material on a substrate, and the application range is wide.

[0031] The photothermal conversion nanoparticles are preferably hydrophobic photothermal conversion nanoparticles, including one or more of zirconium carbide, graphene and carbon nanotubes. The use of hydrophobic photothermal conversion nanoparticles can improve the hydrophobicity of the nano-pore photothermal conversion material layer, and in combination with the nano-pore structure, the super-hydrophobic function can be realized, the limited effect of the nano-pore is improved, and water distribution to the entire space is prevented, affecting the limited water nano effect.

[0032] Preferably, the hydrophilic material is filled into the nano-pore by an atomic layer deposition method. Researches of the application show that only when the hydrophilic material is filled into the nano-pore, that is, the hydrophobic material layer does not contain the hydrophilic material outside, the water evaporation enthalpy has a good reduction effect; when the hydrophilic material is deposited excessively and deposited into a film outside the hydrophobic material layer, the non-local space outside will increase the evaporation enthalpy. Therefore, the application preferably uses the atomic layer deposition method for embedding and filling, which can use pulse gas phase penetration to uniformly embed the hydrophilic molecules in the nano-pore, achieving a better effect.

[0033] By embedding the hydrophilic material in the nano-pore, the application not only can construct a high water absorption limited water space, but also can improve the stability and load firmness of the photothermal conversion nanoparticles through the binding effect of the nano-pore, so that multiple gain effects are realized through a simple preparation method, and chemical modification is not needed, so the universality is high.

[0034] The thickness of the nano-porous light-heat conversion material layer is 50-800 nm, for example, 50-100 nm, 100-200 nm, 200-500 nm, or 500-800 nm. The pore size of the nano-pores is 3-50 nm, for example, 3-10 nm, 10-20 nm, or 20-50 nm. The present application can construct a two-dimensional limited water type high-efficiency light-heat evaporation material with a nanometer-level thickness, which can be used for the preparation of micro devices, and can also be constructed on the surface of a three-dimensional light-heat substrate to further improve the water evaporation efficiency.

[0035] For example, a nano-porous light-heat conversion material layer with a thickness of about 200 nm is prepared, and then a hydrophilic material with different thicknesses (9 nm-200 nm) is embedded into the nano-pores of the light-heat conversion material layer by adjusting the number of cycles (50-1000 cycles) of atomic layer deposition, so as to adjust the number of limited spaces.

[0036] The hydrophilic material is a hydrophilic inorganic oxide or an organic material containing one or more of carboxyl, sulfonate, hydroxyl, amino, and quaternary ammonium salt. The hydrophilic inorganic oxide includes one or more of titanium dioxide, aluminum oxide, and silicon dioxide; and the organic material includes one or more of acrylic acid. When titanium dioxide is selected, its hydrophilicity can be further improved by ultraviolet light irradiation.

[0037] The limited water type high-efficiency light-heat evaporation material further includes a hydrophilic substrate, which is obtained by dip coating or spray coating the hydrophobic nano-particle suspension onto the surface of the hydrophilic substrate; and the hydrophilic substrate is preferably a fiber-based hydrophilic substrate, and the material includes one or more of cotton, cellulose, and polyimide. In this way, the limited water type high-efficiency light-heat evaporation material can be made to float on the water surface to be treated by using the water absorption of the hydrophilic substrate, and the interface water can be adsorbed into the limited space, so as to perform light-heat water evaporation treatment.

[0038] For example, in a specific embodiment, a detergent solution is used to perform hydrophilic treatment on a substrate, a dispersion of hydrophobic nano-material is configured, the hydrophobic nano-material is coated on the surface of the substrate by dip coating, the coated substrate has superhydrophobicity, and the obtained hydrophobic nano-composite flexible substrate is subjected to multiple pulse vapor infiltration (MPI) by atomic layer deposition (ALD). The amorphous hydrophilic coating will slowly penetrate between the hydrophobic coatings from the substrate of the material by this method, the hydrophilic region will be formed between the hydrophobic materials, and water will be limited between the hydrophobic materials, thereby forming the limited space. Since the thickness of the nano-coating prepared by ALD can be adjusted, the number of limited spaces can be adjusted by adjusting the number of cycles of atomic layer deposition.

[0039] Specifically, cut the cotton fabric into 5×5cm pieces. Place it in 1.5L of boiling detergent solution and wash it three times to remove surface impurities. Rinse off any detergent residue on the cotton fabric with deionized water, then dry it for later use.

[0040] Weigh 2g of nano-zirconium carbide (50nm) and add it to 400-500mL of deionized water. Then add 6-8mL of glacial acetic acid, stir with a glass rod for a few minutes, sonicate for 1 hour, and magnetically stir for 30 minutes to prepare a zirconium carbide suspension.

[0041] Cotton fabric was placed in a zirconium carbide suspension and magnetically stirred for 1 hour to obtain cotton fabric with preliminary zirconium carbide treatment. The dried material was then placed in a zirconium carbide suspension and magnetically stirred for 1 hour. This process was repeated 6 to 8 times to obtain the treated cotton fabric. Finally, the cotton fabric was placed in deionized water for ultrasonic removal to remove excess zirconium carbide particles. The fabric was then dried again at 80°C to finally construct a zirconium carbide nano-coating on the surface of the cotton fabric.

[0042] Taking the deposition of titanium dioxide as an example, the deposition method includes: transferring the composite cotton fabric to the ALD reaction chamber and constructing a titanium dioxide nano-coating on its surface. The hydrophilic substrate facilitates the penetration of titanium dioxide into the underlying layer, allowing for deposition and filling from the bottom layer upwards, ultimately filling the nanopores across the entire thickness. The specific parameters of ALD are:

[0043] Reaction chamber temperature: 150℃; titanium source: isopropyl titanate; oxygen source: deionized water; carrier gas: high-purity nitrogen, flow rate: 50 sccm. The titanium source pulse duration is 0.1-10 s, and the permeation time is 5-20 s; followed by rinsing with high-purity nitrogen for 5-40 s. The oxygen source pulse duration is 0.05-5 s, and the permeation time is 5-20 s; followed by rinsing with high-purity nitrogen for 5-40 s to remove reaction byproducts and residual reaction sources. This process constitutes one cycle. After 50-1000 atomic layer deposition cycles (e.g., 50, 600, 1000), the construction of titanium dioxide / hydrophobic nanoparticle micro / nanostructures on the natural fiber-based surface is completed.

[0044] A confined water-based high-efficiency photothermal evaporation device is prepared using any one of the confined water-based high-efficiency photothermal evaporation materials described above.

[0045] This invention constructs a more effective confined water structure through hydrophilic and hydrophobic structures and nano-effects. Furthermore, it can easily construct disordered nanoporous structures by distributing hydrophobic nanoparticles, breaking the technical bias of existing technologies that mostly use ordered one-dimensional, two-dimensional, or three-dimensional pore structures to construct confined water structures. This significantly expands the preparation pathways of this type of material and simplifies the preparation method, which is of great significance to the field of photothermal conversion interface evaporation.

[0046] Example 1

[0047] A confined water-based high-efficiency photothermal evaporation material comprises a zirconium carbide hydrophobic material layer with nanopores and titanium dioxide filling the nanopores. The zirconium carbide hydrophobic material layer (particle size approximately 50 nm) is formed by impregnating zirconium carbide nanoparticles onto a cotton fabric substrate to create nanopores, with a thickness of 100-200 nm and a pore size of 3-20 nm. Then, titanium dioxide is filled into the nanopores through multiple pulsed gas-phase infiltration processes to obtain a confined water-based high-efficiency photothermal evaporation cotton fabric sample.

[0048] like Figure 2 As shown, the atomic layer deposition of titanium dioxide can penetrate under the nano-zirconium carbide layer, forming a structure in which the titanium dioxide layer encapsulates the nano-zirconium carbide particles (with a thickness of about 150 nm). Through this structural design, the hydrophilic titanium dioxide coating will supply water to the spaces between the nano-zirconium carbide particles to form confined water.

[0049] from Figure 3 and 4 It can be seen that atomic layer deposition of titanium dioxide, with 600 deposition cycles, can reduce the enthalpy of evaporation of water at the evaporation interface to a minimum of 1895.45 kJ / kg (at 40℃). Figure 4 This aligns with the theory that confined water can reduce the enthalpy of evaporation. Under one sun, this nanostructure can reduce the evaporation limit of two-dimensional materials to 1.47 kg m³ by lowering the enthalpy of evaporation. -2 h -1 Increased to 1.73 kg m -2 h -1 ( Figure 3 The enthalpy of vaporization initially decreases and then increases with the number of titanium dioxide atom deposition cycles. When the number of cycles reaches 600, the titanium dioxide just fills the nanopores of zirconium carbide. When titanium dioxide atoms spill over to the surface of the zirconium carbide nanoparticles, the enthalpy of vaporization decreases. This is because the outer layer of titanium dioxide does not have a confined space, which affects the confined water nano-effect of the inner layer.

[0050] Example 2

[0051] A confined water-type low enthalpy-of-evaporation composite structure differs from Example 1 in that titanium dioxide is replaced with aluminum oxide. Otherwise, it is largely the same as Example 1 and will not be described further.

[0052] The photothermal conversion particles and hydrophilic materials of the present invention are not limited to the above embodiments. When other hydrophobic particles, such as carbon nanotubes and graphene, and other hydrophilic materials, such as silicon dioxide and acrylic acid, are used, the enthalpy of water evaporation can also be reduced to varying degrees.

[0053] In summary, the confined water-based high-efficiency photothermal evaporation material and device provided by this invention constructs a nanoporous photothermal conversion material layer and fills the nanopores with hydrophilic materials to form a highly water-absorbing confined evaporation structure. This alters the evaporation pattern of water molecules within the confined space, reducing the enthalpy of evaporation and thus significantly improving the evaporation rate and photothermal conversion efficiency. This invention allows for structural design at a two-dimensional level, forming a micro-nano confined space, significantly increasing the water evaporation per unit area and consequently improving the utilization rate of the photothermal conversion material. Therefore, both manufacturing and energy costs are significantly reduced. Furthermore, it overcomes the limitations of confined structure materials, providing a new preparation method and approach for improving evaporation rates based on nanostructures that reduce the enthalpy of evaporation.

[0054] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A confined water-based high-efficiency photothermal evaporation material, characterized in that, It includes a nanoporous photothermal conversion material layer and a hydrophilic material filled in the nanopores to form a highly water-absorbing confined evaporation structure; the hydrophilic material is not deposited on the outside of the nanoporous photothermal conversion material layer; The photothermal conversion nanoparticles are hydrophobic photothermal conversion nanoparticles, including one or more of zirconium carbide, graphene, and carbon nanotubes; The hydrophilic material is one or more of titanium dioxide, aluminum oxide, and silicon dioxide; The nanoporous photothermal conversion material layer is obtained by impregnating a suspension of photothermal conversion nanoparticles, and the nanopores are the pores formed between the photothermal conversion nanoparticles.

2. The confined water-based high-efficiency photothermal evaporation material according to claim 1, characterized in that, The thickness of the nanoporous photothermal conversion material layer is 50-200 nm; the pore size of the nanopore is 3-60 nm.

3. The confined water-based high-efficiency photothermal evaporation material according to claim 2, characterized in that, The thickness of the nanoporous photothermal conversion material layer is 80-120 nm.

4. The confined water-based high-efficiency photothermal evaporation material according to claim 2, characterized in that, The pore size of the nanopore is 5-20 nm.

5. The confined water-based high-efficiency photothermal evaporation material according to claim 1, characterized in that, The hydrophilic material is filled into the nanopores by atomic layer deposition.

6. The confined water-based high-efficiency photothermal evaporation material according to claim 5, characterized in that, A nanoporous photothermal conversion material layer is prepared, and then the number of atomic layer deposition cycles is adjusted to embed hydrophilic materials of different thicknesses into the nanopores of the photothermal conversion material layer, thereby adjusting the amount of confined space.

7. A confined water-based high-efficiency photothermal evaporation device, characterized in that, The confined water high-efficiency photothermal evaporation device is prepared using any one of claims 1 to 6 and is used to improve solar energy conversion capability.

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