A composite material solar interface evaporation device and a preparation method and application thereof

Abstract

The application provides a composite solar interface evaporation device and a preparation method and application thereof, and the solar interface evaporation device comprises a photothermal layer and a support layer, and a plurality of fluid transport channels are formed on the support layer. The photothermal layer combines carbon nanotubes and silver particles to form a high-efficiency light-heat conversion film, thereby improving the light-heat conversion efficiency; PVA is used as a solidification film-forming agent, and a PVA aqueous solution is first sprayed on the surface of the support layer by a layering spraying method, and then the photothermal layer is sprayed on the surface of the PVA film layer, so as to prevent the photothermal layer from being peeled off from the support layer; the support layer is prepared into a hollow conical support structure by a selective laser sintering (SLS) 3D printing technology, and a capillary triangular tooth type groove is designed as the fluid transport channel. The evaporation device realizes efficient light-heat energy utilization, a high seawater evaporation rate and biological pollution resistance, and has the advantages of low preparation cost, long service life, green environmental protection and the like, and has a wide application prospect in the fields of seawater desalination and sewage treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar energy utilization and nanomaterials, and in particular to a composite material solar interface evaporation device and a preparation method and application thereof. BACKGROUND

[0002] Solar-driven interfacial water evaporation technology, which realizes efficient light-to-heat conversion and phase change heat transfer on the surface of water body by locally coupling light absorption and evaporation interface, is widely considered as a promising route to achieve sustainable seawater desalination, wastewater purification and water-electricity cogeneration. Such devices are usually composed of a light-heat absorption layer, a thermal insulation layer, a water transport channel and a condensation collection module, etc. The composition and structural design of the light-heat material play a key role in determining the solar energy capture efficiency, heat management behavior and evaporation interface stability.

[0003] The commonly used light-heat conversion materials in the current interfacial evaporation mainly include carbon-based materials, metal plasmonic materials and polymer-based materials. Carbon-based materials have the advantages of wide spectral absorption and low cost, but generally lack adjustable band gap to achieve targeted spectral absorption. Metal plasmon can produce strong localized surface plasmon resonance (LSPR), but the material cost is high and it is easy to corrode or lose stability in high salinity or complex water bodies. Although polymer-based materials are easy to process, their light-heat conversion ability is usually weak and they are difficult to use independently as high-efficiency light-heat layers. In addition, most light-heat materials are easily affected by microbial attachment and biological pollution when in contact with complex water bodies for a long time, resulting in degradation of light-heat performance and decline of evaporation stability.

[0004] In terms of support structure, polymer materials have attracted much attention due to their good thermal insulation performance and self-floating ability, but the existing structural design still lacks sufficient coordination between light-heat conversion, fluid transport and heat management. For example, the common plane or simple three-dimensional structure is difficult to balance efficient water transport, sufficient light absorption and effective heat localization, which easily leads to large body heat loss, evaporation interface dry area formation or salt accumulation blockage, etc.

[0005] In addition, the interface bonding strength between the light-heat functional layer and the support structure in the existing evaporation device is insufficient, and it is easy to cause coating peeling or structural damage under the long-term thermal-hydraulic coupling, which seriously affects the stability and service life of the evaporation device. The above problems jointly restrict the large-scale application of solar interfacial evaporation technology in actual seawater desalination and wastewater treatment scenarios. SUMMARY

[0006] The present application is carried out to solve the above problems, and aims to provide a composite material solar interface evaporation device and a preparation method and application thereof.

[0007] The application provides a composite solar interface evaporation device, which has the characteristics that the device comprises a support layer obtained by sintering nylon PA12 and provided with a plurality of fluid transport channels; and a photothermal layer, which is a carbon nanotube-silver particle photothermal layer, and is coated on the surface of the support layer.

[0008] In the composite solar interface evaporation device provided by the application, the support layer can be conical, and the plurality of fluid transport channels can be uniformly distributed on the surface of the support layer in a circumferential direction, and the fluid transport channels can be in the form of teeth, and the extension direction of the fluid transport channels can be consistent with the extension direction of the generatrix of the support layer.

[0009] In the composite solar interface evaporation device provided by the application, the fluid transport channels can extend from the bottom surface to the top surface of the support layer, and the width of the fluid transport channels can gradually decrease in the direction from the bottom surface to the top surface.

[0010] The application further provides a preparation method of the composite solar interface evaporation device, which is used for preparing the composite solar interface evaporation device and has the characteristics that the method comprises the following steps: S1: carboxyl multi-walled carbon nanotubes are weighed and added into ethanol, and then silver nitrate solution is added to obtain solution A; ascorbic acid is dissolved in deionized water to obtain solution B; the solution A is shaken and solution B is added dropwise during the shaking process to prepare a carbon nanotube-silver particle mixture; S2: PA12 powder material is sintered into a preset shape to form a support layer; S3: the support layer is subjected to chemical etching, and then PVA aqueous solution is sprayed on the surface of the support layer and dried; the carbon nanotube-silver particle mixture is sprayed on the surface of the support layer covered with the PVA film after drying and dried to form a photothermal layer on the surface of the support layer, thereby obtaining the composite solar interface evaporation device.

[0011] In the preparation method of the composite solar interface evaporation device provided by the application, the concentration of the silver nitrate solution can be 0.05-0.15 mol / L, the mass ratio of the carboxyl multi-walled carbon nanotubes, ethanol and silver nitrate solution can be 2-4:240-260:20-40, and the ratio of ascorbic acid to deionized water can be 1:9-11 (m / v).

[0012] In the preparation method of the composite solar interface evaporation device provided by the application, the chemical etching method can be that the support layer is immersed in a NaOH solution for water bath, and then taken out and washed to remove the excess NaOH solution, and then dried.

[0013] In the preparation method of the composite solar interface evaporation device, the concentration of the NaOH solution can be 4-6 mol / L, the temperature of the water bath can be 55-65 DEG C, and the time can be 25-35 min.

[0014] In the preparation method of the composite solar interface evaporation device, the mass concentration of the PVA aqueous solution in S3 can be 9%-11%.

[0015] In the preparation method of the composite solar interface evaporation device, the method for forming the photothermal layer on the surface of the support layer in S3 can be as follows: after drying, the PVA film-coated support layer surface is sprayed with a carbon nanotube-silver particle mixture and dried, and the spraying and drying are repeated for multiple times to form the photothermal layer on the surface of the support layer.

[0016] The application also provides application of the composite solar interface evaporation device in the fields of seawater desalination and sewage treatment.

[0017] Compared with the prior art, the application has the following advantages:

[0018] The application also provides a preparation method of a cobalt-based intermetallic carbide material and application thereof, and has the following beneficial effects:

[0019] The evaporation device has a good evaporation rate: under 1 standard solar radiation intensity, the seawater evaporation rate reaches 1.762 kg·m -2 ·h -1 , and the evaporation efficiency can reach 94.87% after deducting the dark evaporation, which is better than most carbon-based evaporators. The evaporation device has excellent directional salt deposition capacity: during 12 hours of seawater evaporation, salt is only deposited in the form of a ring-shaped salt circle at the top end, and the fluid transport channel is not blocked, which does not affect fluid evaporation. The evaporation device also has excellent service life: during a week of continuous evaporation, no structural collapse or photothermal layer peeling is found.

[0020] The evaporation device is driven by solar energy and has excellent water treatment capacity through efficient interface evaporation. During seawater desalination treatment, the evaporation device can efficiently convert seawater into pure water vapor for purification. The evaporation device has high seawater desalination capacity and long-term use performance, and has wide application prospects in the fields of seawater desalination and sewage treatment. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic diagram of the microstructure of the carbon nanotube-silver particle in test example 1 of the application.

[0022] Figure 2 is a carbon nanotube-silver particle XRD characterization chart in test example 2 of the present application.

[0023] Figure 3 is a comparison chart of the light-heat conversion of different solar interface evaporation devices in test example 3 of the present application.

[0024] Figure 4 is an evaporation efficiency chart of a composite solar interface evaporator in test example 4 of the present application.

[0025] Figure 5 is a 12-hour salt crystallization chart of a composite solar interface evaporator in test example 5 of the present application. DETAILED DESCRIPTION

[0026] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the following examples combine the drawings to specifically describe the composite solar interface evaporation device, its preparation method and application.

[0027] Example 1

[0028] The present embodiment provides a composite solar interface evaporation device, its preparation method and application.

[0029] The composite solar interface evaporation device provided in the present embodiment comprises a support layer and a light-heat layer.

[0030] The support layer is conical and can float by itself, and is prepared by selective laser sintering (SLS) 3D printing technology using nylon PA12 powder material. PA12 has the characteristics of rough surface and low thermal conductivity, and has excellent heat insulation performance and powder material adsorption.

[0031] A plurality of fluid transport channels are formed on the support layer and are uniformly distributed on the surface of the support layer in the circumferential direction. The fluid transport channels are tooth-shaped capillary flow channels, which transport fluid by capillary force to spread the fluid into a film on the surface of the evaporator. The extension direction of the fluid transport channels is consistent with the extension direction of the generatrix of the support layer, and extends from the bottom surface to the top surface of the support layer. The width of the fluid transport channels gradually decreases in the direction from the bottom surface to the top surface.

[0032] Specifically, the support layer is designed using solidworks software. The support layer is a hollow conical body with a bottom surface radius of 30 mm, a height of 60 mm and a thickness of 3 mm. 120 tooth-shaped capillary flow channels are uniformly formed on the circumferential direction of the conical body. The cross section of the capillary flow channel is triangular, with a bottom side width of 1 mm and a height of 1 mm.

[0033] The photo-thermal layer is mainly composed of carbon nanotubes, and silver particles are generated in the micro carbon nanotube network structure by coupling nano silver particles to form a carbon nanotube-silver particle (CNT-Ag) photo-thermal layer. The silver particles are obtained by chemical reduction of silver nitrate solution with ascorbic acid, and are loaded in the carbon nanotube network structure to increase the photo-thermal conversion efficiency. The photo-thermal layer is coated on the surface of the support layer.

[0034] The embodiment also provides a preparation method of a composite solar interface evaporation device.

[0035] Step S1 is a preparation step of a carbon nanotube-silver particle mixture: carboxyl multi-walled carbon nanotubes are weighed and added to ethanol, silver nitrate solution is added, and a solution A is obtained by mixing. Ascorbic acid is dissolved in deionized water to obtain a solution B. The solution A is shaken and solution B is slowly added during the shaking process to prepare a carbon nanotube-silver particle mixture. The specific operation steps are as follows:

[0036] Take 300 mg of carboxyl multi-walled carbon nanotubes and add them to 25 mL of ethanol, then add 3 mL of silver nitrate solution and magnetically stir for 10 minutes to obtain a uniformly dispersed solution A. Take 195 mg of ascorbic acid and dissolve it in 2 mL of deionized water and magnetically stir for 10 minutes to obtain solution B. Ultrasonic shaking is performed on solution A, with a power setting of 200 W, an opening time of 5 s, a stopping time of 5 s, and a total running time of 30 min. Solution B is slowly added during the shaking process to prepare a uniformly dispersed solution of carbon nanotubes and silver nanoparticles, i.e., a carbon nanotube-silver particle mixture.

[0037] The concentration of the silver nitrate solution is 0.1 mol / L; the carboxyl carbon nanotubes, ethanol, and silver nitrate are mixed in a mass ratio of 3:250:30; and the ascorbic acid and deionized water are mixed in a ratio of 1:10 (m / v).

[0038] Step S2 is a preparation step of a support layer: nylon 12 powder material is sintered into a predetermined shape to form a support layer. The specific operation steps are as follows:

[0039] A conical three-dimensional model is designed using solidworks software, and a PA12 powder is used as the material by selective laser sintering (SLS) 3D printing technology. A high-power carbon dioxide laser is used to selectively sinter the nylon powder material thin layer according to the predetermined pattern, and the powder particles are fused together. After the thin layer is shaped, a new layer of powder is laid on top, and the process is repeated until the support layer (evaporator base) is completed.

[0040] Step S3 is a one-step assembly preparation step: chemically etching the support layer, then spraying a polyvinyl alcohol (PVA) aqueous solution on the surface of the support layer and drying, spraying a carbon nanotube-silver particle mixture on the surface of the PVA film-coated support layer after drying and drying, to form a photothermal layer on the surface of the support layer, to obtain a composite solar interface evaporation device, and the specific operation steps are as follows:

[0041] The support layer is immersed in a 5 mol / L NaOH solution for water bath, 60°C water bath for 30 min, and after the water bath is completed, the excess NaOH solution is washed with deionized water, and is placed in an oven at 80°C for drying for 10 min. A 10% mass fraction PVA aqueous solution is sprayed on the surface of the support layer using a spray gun to form a PVA film, and the PVA film-coated support layer is placed in an oven at 80°C for drying for 5 minutes. The carbon nanotube-silver particle mixture is uniformly sprayed on the surface of the PVA film using a spray gun, and then placed in an oven at 80°C for drying for 10 min, and the spraying and drying are repeated 3 times to form a CNT-Ag thin layer, i.e. a photothermal layer, on the surface of the support layer, and the preparation of the composite solar interface evaporation device is completed.

[0042] The embodiment also provides applications of the composite solar interface evaporation device in the fields of seawater desalination and sewage treatment.

[0043] Comparative Example 1

[0044] The comparative example provides a preparation method of a solar interface evaporation device containing a pure CNT film without Ag. The difference between the comparative example and Example 1 is that after the carboxylated carbon nanotubes are prepared, the photothermal material is not treated any more, and the specific steps are as follows:

[0045] S1: 300 mg of carboxylated multi-walled carbon nanotubes are added to 25 mL of ethanol, and magnetically stirred for 10 min to obtain a uniformly dispersed carbon nanotube dispersion.

[0046] S2-S3 are the same as in Example 1.

[0047] Comparative Example 2

[0048] The comparative example provides a preparation method of a 2D composite solar interface evaporation device. The difference between the comparative example and Example 1 is that the support layer is a circular support layer with the same projection area as the conical support layer of Example 1, and the other preparation steps remain unchanged.

[0049] Comparative Example 3

[0050] The comparative example provides a preparation method of a solar interface evaporation device without a photothermal layer. The difference between the comparative example and Example 1 is that only the support layer is prepared, and no PVA aqueous solution or photothermal material (carbon nanotube-silver particle mixture) is sprayed.

[0051] Comparative Example 4

[0052] This comparative example provides a preparation method of a 2D solar interface evaporation device without a photothermal layer. The difference between this comparative example and Example 1 is that only a support layer is prepared, the support layer is a circular support layer with the same projected area as the conical support layer of Example 1, and no PVA aqueous solution and photothermal material (carbon nanotube-silver particle mixture) are sprayed.

[0053] Test Example 1

[0054] This test example analyzes the micro-morphology of the CNT-Ag thin layer prepared in Example 1.

[0055] Figure 1 is a schematic diagram of the microstructure of carbon nanotubes-silver particles in Test Example 1 of the present application.

[0056] The results are shown in Figure 1 , the CNT-Ag composite material exhibits a unique multi-scale three-dimensional porous structure. At low magnification Figure 1 (a)- Figure 1 (b), the material exhibits a continuous, rough and highly porous overall morphology, with pore sizes in the tens of microns. This macroscopic porous structure is beneficial for the rapid transport of water and the escape of vapor, and is an ideal structure for constructing efficient solar interface evaporators. High magnification images Figure 1 (c)- Figure 1 (d) further reveal the fine structure of the material. It can be seen that the carbon skeleton network is interwoven to form abundant mesopores and micropores, and a large number of silver metal particles are uniformly embedded or loaded in the carbon matrix. This hierarchical porous structure from microns to nanometers not only greatly increases the specific surface area of the material, providing abundant vaporization sites for water molecules, but also effectively captures incident light through multiple internal reflections, thereby significantly improving light absorption efficiency.

[0057] Test Example 2

[0058] This test example analyzes the XRD crystal structure and composition of the CNT-Ag thin layer prepared in Example 1.

[0059] Figure 2 is a graph of the XRD characterization of carbon nanotubes-silver particles in Test Example 2 of the present application.

[0060] The results are shown in Figure 2As shown, the sharp diffraction peaks (marked as ★) at 38.1°, 44.3°, 64.4° and 77.4° in the diffraction pattern can be attributed to the (111), (200), (220) and (311) planes of face-centered cubic (fcc) silver (Ag) (JCPDS No. 04-004-8504), which clearly confirms the successful formation and existence of elemental silver particles in the composite. Meanwhile, a broad and diffuse diffraction peak (marked as ▲) appears near 25°, corresponding to the (002) plane of graphite carbon (JCPDS No. 97-005-3780), indicating that the carbon matrix is mainly disordered or low crystallinity carbon structure. No other impurity peaks are found in the XRD pattern, indicating that the prepared CNT-Ag composite has high purity. The introduction of metal silver particles is crucial, as its strong localized surface plasmon resonance effect can effectively enhance the light trapping ability of the material in the visible light region, while the carbon matrix provides a wide spectrum of absorption, excellent photothermal stability and the above-mentioned three-dimensional porous framework. The synergistic effect of the two indicates that the composite has great potential in photothermal conversion applications.

[0061] Test Example 3

[0062] In this test example, the solar interface evaporation device (hereinafter referred to as evaporation device) prepared in Example 1 and Comparative Examples 1-4 was subjected to a no-load photothermal conversion test.

[0063] Figure 3 is a comparison chart of the no-load photothermal conversion of different solar interface evaporation devices in Test Example 3 of the present application.

[0064] The results are shown in Figure 3 Under the condition of 1 standard solar irradiance (1 kW m -2 ), the photothermal conversion capacity of the CNT-Ag thin layer, CNT thin layer, 2D and 3D structure evaporation device without a thin layer was compared. The heating process was recorded and analyzed by a thermocouple and an infrared camera to characterize the photothermal conversion performance. As shown in Figure 3 The surface temperature of all test groups of evaporation devices rapidly increased within the first 15 minutes and stabilized after 20 minutes, showing excellent photothermal response capacity. During the 1 hour test time, the temperature of the CNT-Ag thin layer sprayed, CNT-Ag thin film sprayed and 3D evaporator without a thin layer stabilized at 64.9°C, 62.3°C and 54.7°C, respectively. This indicates that the surface of the substrate treated by the photothermal absorption material can significantly increase the photothermal conversion capacity of the evaporator. In both 2D and 3D test groups, the stable temperature of the evaporator sprayed with a CNT-Ag thin layer was higher than that of the evaporator sprayed with a single carbon nanotube thin layer, which indicates that the introduction of silver particles enhances the local light field intensity due to its unique surface plasmon resonance, which promotes more light energy to be absorbed and converted into heat energy, increasing the temperature rise efficiency by nearly 11.6% compared to before the introduction.

[0065] Test Example 4

[0066] In this test example, the composite solar interface evaporation device prepared in Example 1 was subjected to water evaporation test to characterize the evaporation rate of the composite solar interface evaporation device.

[0067] Figure 4 Figure for evaporation efficiency of the composite solar interface evaporator in Test Example 4 of the present application.

[0068] The results are shown in Figure 4 , under standard one sun irradiance (1 kW m -2 ) conditions, the system evaluated the seawater evaporation behavior of the evaporation device of Example 1 and the self-evaporation behavior of seawater without the evaporation device. Figure 4 It can be seen that in the evaporation process of the evaporation device of Example 1, the evaporation rate is 1.762 kg·m -2 ·h -1 ; the seawater evaporation rate in the self-evaporation behavior of seawater is 0.562 kg·m -2 ·h -1 . By comparison, it can be found that the evaporation rate of the evaporation device of Example 1 is 3.13 times higher than that of seawater self-evaporation. And the evaporation efficiency of the evaporation device of Example 1 after deducting the dark evaporation is 94.86%, far exceeding the self-evaporation efficiency of seawater 17.74%.

[0069] Test Example 5

[0070] In this test example, the composite solar interface evaporation device prepared in Example 1 was subjected to salt resistance test to characterize the directional salt crystallization ability of the composite solar interface evaporation device.

[0071] Figure 5 Figure for 12-hour salt crystallization of the composite solar interface evaporator in Test Example 5 of the present application.

[0072] The results are shown in Figure 5 , under standard one sun irradiance (1 kW m -2 ) conditions, the system evaluated the salt crystallization of the evaporation device of Example 1 after 12 hours of seawater evaporation, and Figure 5It can be seen that the salt crystallization is strictly limited to the top area of the evaporator, and the evaporation interface is always clean, and no evaporation flux attenuation caused by lateral diffusion of crystallization or interface blockage is observed. This result proves that the geometry-induced directional crystallization strategy can effectively decouple the evaporation and crystallization processes, not only overcoming the continuous performance decline problem of traditional flat evaporators caused by salt layer coverage, but also maintaining stable water-salt separation efficiency under continuous operation conditions, providing key experimental basis for extending the design to large-scale and continuous practical application scenarios.

[0073] Effects of the embodiments

[0074] The composite solar interface evaporation device, the preparation method and the application have the following beneficial effects.

[0075] The carboxyl carbon nanotube-silver metal particle composite of the present application has excellent wide-spectrum absorption capacity and high specific surface area, can realize heat localization and rapid transmission at micro-nano scale, and its porous network structure is beneficial to the transport and redistribution of water molecules on the interface. The introduction of silver particles further improves the light-heat conversion efficiency of the material through localized surface plasmon resonance, realizing efficient light-heat conversion. Moreover, the silver metal particles will slowly release silver ions on the surface of the evaporation device, improve the antibacterial and antibiofouling properties of the evaporation device surface in the complex water environment such as seawater, reduce the additional thermal resistance generated by the bacterial mucosa, and prolong the service life of the evaporation device.

[0076] The present application uses PA12 as the support structure of the evaporation device, which is prepared by a laminated spraying method. The overall cost of the evaporation device is low, the technical difficulty is low, it is easy to mass-produce and does not need high-grade external energy driving, and has great application prospect in resource-poor or decentralized water use scenarios.

[0077] The fluid transport channel of the evaporation device is a tooth-shaped capillary flow channel, which can realize enhanced light reflection and recycling of scattered light and thus improve the solar heat conversion efficiency, and optimize the conversion process of light energy to available energy. At the same time, the fluid is affected by the capillary force and climbs up in the tooth-shaped groove flow channel, so that the fluid spreads into a film on the surface of the evaporation device, and the heating area of the water body is increased, and the heat is concentrated on the liquid surface, strengthening the evaporation effect.

[0078] Specifically, according to the results of test example 4, the evaporation device has a good evaporation rate: under 1 standard solar radiation intensity, the seawater evaporation rate reaches 1.762 kg·m -2 ·h -1, the evaporation efficiency can reach 94.87% after deducting the dark evaporation, which is superior to most carbon-based evaporators. As can be known from the result of the test example 5, the evaporation device has excellent directional salt deposition capacity: during the 12-hour seawater evaporation process, the salt is only generated in the form of a ring-shaped salt circle at the top end, and the fluid transport channel is not blocked, and the fluid evaporation is not affected. The evaporation device has excellent service life: during the continuous evaporation process for one week, no phenomenon such as structure collapse and photothermal layer peeling is found.

[0079] In conclusion, the evaporation device is driven by solar energy, and has excellent water treatment capacity through efficient interfacial evaporation. During the seawater desalination process, the seawater can be efficiently converted into pure water vapor for purification. The evaporation device has high seawater desalination capacity and long-term use performance, and has wide application prospects in the fields of seawater desalination and sewage treatment.

[0080] Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A composite material solar interface evaporation device, characterized by, The composite solar interface evaporation device comprises a support layer and a photo-thermal layer. The support layer is obtained by sintering nylon PA12 and is provided with a plurality of fluid transport channels. The photo-thermal layer is a carbon nanotube-silver particle photo-thermal layer and is coated on the surface of the support layer. The support layer is conical, and a plurality of fluid transport channels are uniformly distributed on the surface of the support layer in the circumferential direction. The preparation method of the composite solar interface evaporation device comprises the following steps: S1: carboxyl multi-walled carbon nanotubes are weighed and added into ethanol, and silver nitrate solution is added to obtain solution A; ascorbic acid is dissolved in deionized water to obtain solution B; the solution A is shaken and the solution B is added dropwise during the shaking process to prepare a carbon nanotube-silver particle mixed solution; S2: PA12 powder material is sintered into a predetermined shape to form the support layer; S3: the support layer is chemically etched, then PVA aqueous solution is sprayed on the surface of the support layer and dried, the carbon nanotube-silver particle mixed solution is sprayed on the surface of the support layer coated with the PVA film after drying and dried to form the photo-thermal layer on the surface of the support layer, thereby obtaining the composite solar interface evaporation device.

2. The composite solar interface evaporation device according to claim 1, wherein the fluid transport channels extend from the bottom surface to the top surface of the support layer, and the width of the fluid transport channels gradually decreases from the bottom surface to the top surface. wherein 3. The composite solar interface evaporation device according to claim 1, wherein in S1, the concentration of the silver nitrate solution is 0.05-0.15 mol / L, the mass ratio of carboxyl multi-walled carbon nanotubes, ethanol and silver nitrate solution is 2-4:240-260:20-40, and the ratio of ascorbic acid to deionized water is 1:9-11 (m / v).

4. The composite solar interface evaporation device according to claim 1, wherein in S3, the chemical etching method is: wherein immersing the support layer in a NaOH solution for water bath, taking out and washing the excess NaOH solution after the water bath, and then drying.

5. The composite solar interface evaporation device according to claim 4, wherein the concentration of the NaOH solution is 4-6 mol / L, the water bath temperature is 55-65℃, and the time is 25-35 min. wherein 6. The composite solar interface evaporation device according to claim 1, wherein in S3, the mass concentration of the PVA aqueous solution is 9%-11%.

7. The composite solar interface evaporation device according to claim 1, wherein in S3, the method for forming the photo-thermal layer on the surface of the support layer is: spraying the carbon nanotube-silver particle mixed solution on the surface of the support layer coated with the PVA film after drying and drying, repeating the spraying and drying multiple times to form the photo-thermal layer on the surface of the support layer. wherein ​ ​ wherein ​ ​ wherein, ​ ​ 8. Use of a composite solar interface evaporation device in the field of desalination of seawater and treatment of wastewater, characterized in that: The composite solar interface evaporation device is the composite solar interface evaporation device as claimed in any one of claims 1-7. The composite solar interface evaporation device is the composite solar interface evaporation device as claimed in any one of claims 1-7.

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