Aluminum-based carbon film photothermal evaporator, preparation method and application thereof

Abstract

The application provides an aluminum-based carbon film photothermal evaporator and a preparation method and application thereof. The preparation method is specifically as follows: laser etching is performed on the surface of an Al sheet to obtain an AL sheet with a periodic groove structure, and a product 1 is obtained; a furfural oxalic acid solution is added dropwise into the periodic groove structure on the surface of the product 1, a uniform liquid film is formed on the periodic groove structure on the surface of the product 1, and a product 2 is obtained; the product 2 is subjected to pre-polymerization and carbonization treatment to obtain a product 3; the hydrophilic sites of the product 3 are activated to obtain the aluminum-based carbon film photothermal evaporator. The photothermal conversion efficiency and the evaporation rate of the evaporator are significantly improved. Further combined with a concentrated brine drainage mode, a high-performance interface solar evaporation system with excellent salt resistance and stable and efficient operation in a long-term evaporation process is obtained.

Description

Technical Field

[0001] This invention belongs to the field of photothermal materials technology, specifically to an aluminum-based carbon film photothermal evaporator, its preparation method, and its application. Background Technology

[0002] With rapid population growth and industrialization, freshwater scarcity has limited technological development and threatened human survival. Interfacial solar evaporation (ISE) technology, as a green and low-energy-consumption next-generation freshwater production technology, does not rely on fossil fuels compared to commercial technologies such as reverse osmosis and multi-effect distillation, making it applicable to remote mountainous areas. While breakthroughs in evaporation rate and energy utilization efficiency have been achieved through photothermal material preparation, water transport regulation, and enhanced thermal management, researchers have developed various types of evaporators, including carbon-based, hydrogel, aerogel, paper-based, textile-based, and metal-based evaporators. Among these, metal-based evaporators have attracted researchers' attention due to their high thermal conductivity, strong mechanical properties, durability, convenient transportation, and scalability.

[0003] Interfacial solar-driven water evaporation (ISE) technology, as a green, environmentally friendly, and low-energy-consumption next-generation seawater desalination technology, is one of the important methods to address the increasingly serious freshwater crisis. However, due to the effects of severe weather and seawater corrosion, the mechanical and light absorption performance of ISE systems deteriorates, making it difficult to achieve long-term stable and efficient operation during long-term evaporation. In addition, salt deposition during the evaporation process seriously damages the lifespan of the photothermal absorber, thus affecting the operation of the ISE system and making it difficult to achieve the expected production targets. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an aluminum-based carbon film photothermal evaporator, its preparation method, and its application. Using L-Al as a substrate, a periodic groove structure is formed on the surface of the Al sheet through laser etching technology. This micro-network structure not only optimizes the distribution of photothermal conversion materials and opens channels for effective water diffusion and rapid vapor dissipation through the groove structure design, but also provides stable sites for furfural carbonization adhesion. Combined with the excellent photothermal conversion capability, hydrophilic properties, and enthalpy reduction mechanism of furfural carbon, a significant improvement in photothermal conversion efficiency and evaporation rate is achieved. By combining it with a concentrated brine diversion mode, a high-performance interfacial solar evaporation system with excellent salt barrier properties and stable and efficient operation during long-term evaporation is obtained.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing an aluminum-based carbon film photothermal evaporator, the specific preparation method of which is as follows: Laser etching is performed on the surface of an Al sheet to obtain an Al sheet with a periodic groove structure on the surface, resulting in product 1; Furfural oxalic acid solution was added dropwise to the periodic groove structure on the surface of product 1 until a uniform liquid film was formed on the periodic groove structure on the surface of product 1, thus obtaining product 2. Product 2 was prepolymerized and carbonized to obtain product 3; The hydrophilic sites of product 3 were activated to obtain an aluminum-based carbon film photothermal evaporator.

[0006] Furthermore, in the step of laser etching on the Al sheet surface to obtain an Al sheet with a periodic groove structure on the surface, resulting in product 1, the specific details are as follows: The laser etching range is 2.5 cm × 3.0 cm, the laser spot diameter is 0.05 mm, the laser focal length is 11.0 cm, the spacing between laser beams is 0.1 mm to 0.2 mm, the laser beam scanning path is vertical, and the etching path includes horizontal and vertical directions.

[0007] Furthermore, in the step of laser etching on the Al sheet surface to obtain an Al sheet with a periodic groove structure on the surface, resulting in product 1, the specific details are as follows: The periodic groove structure is a square array composed of multiple square groove structures formed by the intersection of horizontal and vertical etching paths.

[0008] Further, in the step of adding furfural oxalic acid solution dropwise into the periodic groove structure on the surface of product 1 until a uniform liquid film is formed on the periodic groove structure on the surface of product 1 to obtain product 2, the specific details are as follows: A furfural-oxalic acid solution is obtained by mixing oxalic acid and furfural in a molar ratio of 0.01 to 0.011.

[0009] Furthermore, in the step of prepolymerizing and carbonizing product 2 to obtain product 3, specifically: Product 2 was dried at 90℃ for 48 h for prepolymerization.

[0010] Furthermore, in the step of prepolymerizing and carbonizing product 2 to obtain product 3, specifically: The prepolymerized product 2 was placed under a protective atmosphere and carbonized at a temperature of 500℃~800℃ to obtain product 3.

[0011] Furthermore, the flow rate under the protective atmosphere does not exceed 50 sccm.

[0012] The present invention also provides an aluminum-based carbon film photothermal evaporator, which is prepared by the above-described method.

[0013] The present invention also provides an ISE system in which the photothermal absorption layer adopts the above-mentioned aluminum-based carbon film photothermal evaporator.

[0014] Furthermore, based on the concentrated brine diversion mode, a water supply channel and a concentrated brine diversion channel are set on the aluminum-based carbon film photothermal evaporator. The two sides of the aluminum-based carbon film photothermal evaporator are in contact with the head of the water supply channel, and the tail of the water supply channel is in contact with water to supply water to the aluminum-based carbon film photothermal evaporator. The two opposite outer sides of the water supply channel on the aluminum-based carbon film photothermal evaporator are in contact with the head of the concentrated brine diversion channel, and the tail of the concentrated brine diversion channel is connected to the concentrated brine recovery device.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: This invention provides an aluminum-based carbon film photothermal evaporator, which utilizes laser etching technology to form a periodic groove structure on the surface of an Al sheet. This innovative design not only enhances the surface area of ​​the material but also provides stable sites for the adhesion of furfural carbonization. This micro-network structure optimizes the distribution of the photothermal conversion material and, through the groove design, opens channels for effective water diffusion and rapid steam dissipation. This structural design innovation significantly improves the photothermal conversion efficiency and evaporation rate of the aluminum-based carbon film photothermal evaporator.

[0016] Furthermore, thanks to the excellent photothermal conversion capability of furfural carbon, the aluminum-based carbon film photothermal evaporator prepared in this invention can efficiently convert light energy into heat energy under illumination, thereby driving water evaporation. Simultaneously, the hydrophilic properties of furfural carbon and its enthalpy-reducing mechanism further enhance the evaporator's performance. Experimental results show that under 1% solar irradiance, this evaporator can achieve a high evaporation rate of 2.12 kgm³ when desalinating 3.5 wt% simulated seawater. -2 h -1 The invention boasts an evaporation rate and an energy utilization efficiency of 91.8%. This performance improvement makes the invention promising for applications in seawater desalination, wastewater treatment, and other fields.

[0017] This invention also incorporates a concentrated brine diversion mode to obtain a high-performance interface solar evaporation system with excellent salt-blocking performance and stable and efficient operation during long-term evaporation. This feature makes this invention more widely applicable in fields such as seawater desalination that require the treatment of high-salinity water bodies. Attached Figure Description

[0018] Figure 1 The surface morphologies of L-Al and C@L-Al prepared at different carbonization temperatures are shown, where a) L-Al, b) C@L-Al-1, c) C@L-Al-2, and d) C@L-Al-3.

[0019] Figure 2The mass loss of seawater was simulated by different concentrations of C@L-Al-2 desalination.

[0020] Figure 3 Evaporation rate and energy utilization efficiency.

[0021] Figure 4 The evaporation rate of simulated seawater was calculated to be 3.5 wt% over 8 hours.

[0022] Figure 5 The evaporation rate of simulated seawater for 15 cycles was used to achieve an evaporation rate of 3.5 wt%. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1 This invention provides an aluminum-based carbon film photothermal evaporator, the preparation method of which is as follows: (1) Preprocessing of Al film surface Place a 0.4mm thick Al sheet (10 cm × 15 cm) on a non-woven fabric. First, sand it with 2000-grit sandpaper to remove contaminants from the surface. Then, continue sanding with 400-grit sandpaper until it is flat and smooth. Afterward, wipe it clean with an alcohol swab and then dry it with nitrogen gas.

[0025] (2) Periodic groove structure etched on the surface of Al sheet The smoothed and cleaned Al sheet from step 1 is fixed onto the worktable of a laser marking machine (LG20, HGLaser, China). A 20 W power, 90 mm / s laser marking machine is used. -1 A 30 kHz laser beam is vertically irradiated onto the cleaned Al wafer surface for laser etching. The etching area is 2.5 cm × 3.0 cm, the laser spot diameter is 0.05 mm, and the focal length is 11.0 cm. The laser beam scanning path is vertical. The spacing between the laser beams is adjusted to 0.15 mm to etch the Al wafer surface. The resulting laser-treated Al wafer is called L-AL.

[0026] (3) Polymerize furfural on the surface of L-AL sheets with a periodic groove structure. 1) Mix oxalic acid and furfural, stir for 15 minutes in a dark environment to obtain furfural oxalic acid solution, and then place it in a cool, dark place for later use.

[0027] The molar ratio of oxalic acid to furfural is 0.01.

[0028] 2) The above oxalic acid / furfuryl alcohol solution was slowly added dropwise to the L-Al surface. The mixed solution diffused on the L-Al surface under capillary action. The liquid film of the mixed solution added to L-Al was uniform. Then the above sample was placed in a 90 ℃ oven to dry for 48 h to prepolymerize furfural and obtain sample 1 with a brownish-black surface.

[0029] 3) Sample 1 was placed in a crucible and carbonized at 500°C under a nitrogen atmosphere with a flow rate of 20 sccm. After the temperature of the tube furnace dropped to room temperature, sample 2, with a black surface, was removed. Then, the carbonized sample 2 was immersed in deionized water for 72 h to activate the hydrophilic sites. Finally, sample 2 was dried in a 60°C forced-air drying oven for 12 hours to obtain an aluminum-based carbon film photothermal evaporator, named C@L-Al-1.

[0030] Example 2 This invention provides an aluminum-based carbon film photothermal evaporator, the preparation method of which is as follows: (1) Preprocessing of Al film surface Place a 0.4mm thick Al sheet (10 cm × 15 cm) on a non-woven fabric. First, sand it with 2000-grit sandpaper to remove contaminants from the surface. Then, continue sanding with 400-grit sandpaper until it is flat and smooth. Afterward, wipe it clean with an alcohol swab and then dry it with nitrogen gas.

[0031] (2) Periodic groove structure etched on the surface of Al sheet The smoothed and cleaned Al sheet from step 1 is fixed onto the worktable of a laser marking machine (LG20, HGLaser, China). A 20 W power, 90 mm / s laser marking machine is used. -1 A 30 kHz laser beam is vertically irradiated onto the cleaned Al wafer surface for laser etching. The etching area is 2.5 cm × 3.0 cm, the laser spot diameter is 0.05 mm, and the focal length is 11.0 cm. The laser beam scanning path is vertical. The spacing between the laser beams is adjusted to 0.15 mm to etch the Al wafer surface. The resulting laser-treated Al wafer is called L-AL.

[0032] (3) Polymerize furfural on the surface of L-AL sheets with a periodic groove structure. 1) Mix oxalic acid and furfural, stir for 15 minutes in a dark environment to obtain furfural oxalic acid solution, and then place it in a cool, dark place for later use.

[0033] The molar ratio of oxalic acid to furfural is 0.01.

[0034] 2) The above oxalic acid / furfuryl alcohol solution was slowly added dropwise to the L-Al surface. The mixed solution diffused on the L-Al surface under capillary action. The liquid film of the mixed solution added to L-Al was uniform. Then the above sample was placed in a 90 ℃ oven to dry for 48 h to prepolymerize furfural and obtain sample 1 with a brownish-black surface.

[0035] 3) Place sample 1 in a crucible and carbonize it at 700℃ under a nitrogen atmosphere with a flow rate of 20 sccm (not exceeding 50 sccm). After the temperature of the tube furnace drops to room temperature, remove sample 2, which has a black surface. Then, immerse the carbonized sample 2 in deionized water for 72 h to activate the hydrophilic sites. Finally, dry sample 2 in a 60 ℃ forced-air drying oven for 12 hours to obtain an aluminum-based carbon film photothermal evaporator, named C@L-Al-2.

[0036] Example 3 This invention provides an aluminum-based carbon film photothermal evaporator, the preparation method of which is as follows: (1) Preprocessing of Al film surface Place a 0.4mm thick Al sheet (10 cm × 15 cm) on a non-woven fabric. First, sand it with 2000-grit sandpaper to remove contaminants from the surface. Then, continue sanding with 400-grit sandpaper until it is flat and smooth. Afterward, wipe it clean with an alcohol swab and then dry it with nitrogen gas.

[0037] (2) Periodic groove structure etched on the surface of Al sheet The smoothed and cleaned Al sheet from step 1 is fixed onto the worktable of a laser marking machine (LG20, HGLaser, China). A 20 W power, 90 mm / s laser marking machine is used. -1 A 30 kHz laser beam is vertically irradiated onto the cleaned Al wafer surface for laser etching. The etching area is 2.5 cm × 3.0 cm, the laser spot diameter is 0.05 mm, and the focal length is 11.0 cm. The laser beam scanning path is vertical. The spacing between the laser beams is adjusted to 0.15 mm to etch the Al wafer surface. The resulting laser-treated Al wafer is called L-AL.

[0038] (3) Polymerize furfural on the surface of L-AL sheets with a periodic groove structure. 1) Mix oxalic acid and furfural, stir for 15 minutes in a dark environment to obtain furfural oxalic acid solution, and then place it in a cool, dark place for later use.

[0039] The molar ratio of oxalic acid to furfural is 0.01.

[0040] 2) The above oxalic acid / furfuryl alcohol solution was slowly added dropwise to the L-Al surface. The mixed solution diffused on the L-Al surface under capillary action. The liquid film of the mixed solution added to L-Al was uniform. Then the above sample was placed in a 90 ℃ oven to dry for 48 h to prepolymerize furfural and obtain sample 1 with a brownish-black surface.

[0041] 3) Sample 1 was placed in a crucible and carbonized at 800℃ under a nitrogen atmosphere with a flow rate of 20 sccm. After the temperature of the tube furnace cooled to room temperature, sample 2, with a black surface, was removed. Then, the carbonized sample 2 was immersed in deionized water for 72 h to activate the hydrophilic sites. Finally, sample 2 was dried in a 60℃ forced-air drying oven for 12 hours to obtain an aluminum-based carbon film photothermal evaporator, named C@L-Al-3.

[0042] Example 4 This invention provides an aluminum-based carbon film photothermal evaporator, the preparation method of which is as follows: (1) Preprocessing of Al film surface Place a 0.4mm thick Al sheet (10 cm × 15 cm) on a non-woven fabric. First, sand it with 2000-grit sandpaper to remove contaminants from the surface. Then, continue sanding with 400-grit sandpaper until it is flat and smooth. Afterward, wipe it clean with an alcohol swab and then dry it with nitrogen gas.

[0043] (2) Periodic groove structure etched on the surface of Al sheet The smoothed and cleaned Al sheet from step 1 is fixed onto the worktable of a laser marking machine (LG20, HGLaser, China). A 20 W power, 90 mm / s laser marking machine is used. -1 A 30 kHz laser beam is vertically irradiated onto the cleaned Al wafer surface to perform laser etching. The laser beam etching area is 2.5 cm × 3.0 cm, the laser spot diameter is 0.05 mm, and the laser focal length is 11.0 cm. The laser beam scanning path is vertical. The spacing between the laser beams is adjusted to 0.2 mm to etch the Al wafer surface. The resulting laser-treated Al wafer is called L-AL.

[0044] (3) Polymerize furfural on the surface of L-AL sheets with a periodic groove structure. 1) Mix oxalic acid and furfural, stir for 15 minutes in a dark environment to obtain furfural oxalic acid solution, and then place it in a cool, dark place for later use.

[0045] The molar ratio of oxalic acid to furfural is 0.011.

[0046] 2) The above oxalic acid / furfuryl alcohol solution was slowly added dropwise to the L-Al surface. The mixed solution diffused on the L-Al surface under capillary action. The liquid film of the mixed solution added to L-Al was uniform. Then the above sample was placed in a 90 ℃ oven to dry for 48 h to prepolymerize furfural and obtain sample 1 with a brownish-black surface.

[0047] 3) Sample 1 was placed in a crucible and carbonized at 600℃ under an argon atmosphere with a flow rate of 30 sccm. After the temperature of the tube furnace cooled to room temperature, sample 2, with a black surface, was removed. Then, the carbonized sample 2 was immersed in deionized water for 72 h to activate the hydrophilic sites. Finally, sample 2 was dried in a 60℃ forced-air drying oven for 12 hours to obtain an aluminum-based carbon film photothermal evaporator, named C@L-Al-4.

[0048] Example 5 This invention provides an aluminum-based carbon film photothermal evaporator, the preparation method of which is as follows: (1) Preprocessing of Al film surface Place a 0.4mm thick Al sheet (10 cm × 15 cm) on a non-woven fabric. First, sand it with 2000-grit sandpaper to remove contaminants from the surface. Then, continue sanding with 400-grit sandpaper until it is flat and smooth. Afterward, wipe it clean with an alcohol swab and then dry it with nitrogen gas.

[0049] (2) Periodic groove structure etched on the surface of Al sheet The smoothed and cleaned Al sheet from step 1 is fixed onto the worktable of a laser marking machine (LG20, HGLaser, China). A 20 W power, 90 mm / s laser marking machine is used. -1 A 30 kHz laser beam is vertically irradiated onto the cleaned Al wafer surface to perform laser etching. The laser beam etching area is 2.5 cm × 3.0 cm, the laser spot diameter is 0.05 mm, and the laser focal length is 11.0 cm. The laser beam scanning path is vertical. The spacing between the laser beams is adjusted to 0.1 mm to etch the Al wafer surface. The resulting laser-treated Al wafer is called L-AL.

[0050] (3) Polymerize furfural on the surface of L-AL sheets with a periodic groove structure. 1) Mix oxalic acid and furfural, stir for 15 minutes in a dark environment to obtain furfural oxalic acid solution, and then place it in a cool, dark place for later use.

[0051] The molar ratio of oxalic acid to furfural is 0.0105.

[0052] 2) The above oxalic acid / furfuryl alcohol solution was slowly added dropwise to the L-Al surface. The mixed solution diffused on the L-Al surface under capillary action. The liquid film of the mixed solution added to L-Al was uniform. Then the above sample was placed in a 90 ℃ oven to dry for 48 h to prepolymerize furfural and obtain sample 1 with a brownish-black surface.

[0053] 3) Sample 1 was placed in a crucible and carbonized at 500℃, 700℃, and 800℃ under an argon atmosphere at a flow rate of 50 sccm. After the temperature of the tube furnace cooled to room temperature, sample 2, with a black surface, was removed. Then, the carbonized sample 2 was immersed in deionized water for 72 h to activate the hydrophilic sites. Finally, sample 2 was dried in a 60℃ forced-air drying oven for 12 hours to obtain an aluminum-based carbon film photothermal evaporator, named C@L-Al-5.

[0054] This invention uses a concentrated brine drainage pattern to assemble an ISE system. The ISE system specifically includes filter paper, a beaker of polystyrene (PS) foam, and the aforementioned aluminum-based carbon film photothermal evaporator. Small pieces of PS foam are placed at the bottom of a 50ml container, which is then placed inside a 250ml container to create a height difference. Two 2cm × 5cm strips of filter paper are cut as water supply channels, and two 0.5cm × 8cm strips of filter paper are cut as concentrated brine drainage channels. The heads of the water supply channels are placed on the left and right sides of the aluminum-based carbon film photothermal evaporator, while the tails are placed in simulated seawater, responsible for supplying water to the evaporator material. The heads of the concentrated brine drainage channels are placed on the two outer sides opposite the water supply channels. The heads of these two filter paper strips are close to the evaporator material, responsible for collecting and draining the concentrated brine left after evaporation, while the tails extend into the 250ml beaker to collect this concentrated brine. The absorber is placed flat on the PS foam. The area of ​​the PS foam is much larger than the area of ​​the beaker to prevent the incident light from the simulated light source from entering the evaporator system.

[0055] Figure 1 To observe the surface morphology of L-Al and C@L-AL prepared at carbonization temperatures of 500℃, 700℃, and 800℃ using SEM. Figure 1a) The surface morphology of L-Al. Under laser etching, a distinct periodic groove structure was formed. Two types of "pit-like" structures appeared during the lateral and longitudinal laser path etching process: one is the superposition of lateral and longitudinal groove structures caused by laser etching, and the other is the exposed Al sheet surface that was not etched by the laser. This is because the intense thermal effect causes the Al substrate irradiated by the laser beam to vaporize, melt, and cut. The Al located at the edge of the laser beam forms rod-shaped and granular skeletons under the thermal effect. These skeletons curl under stress and obscure the groove structure and the exposed Al sheet surface, resulting in an indistinct boundary between the two structures. Under high magnification, rough surface nanostructures such as velvety and broccoli-like patterns can be observed on the skeleton structure. This rough surface structure provides capillary force to allow water to diffuse on the grooves and skeleton. The groove and skeleton structures provide directional flow channels for water transport and ensure the escape of water vapor. Figure 1 As shown in Figure 2, the L-Al framework structure is retained after high-temperature treatment following furfural carbonization. Furthermore, the originally gentle lateral structure of L-Al exhibits noticeable unevenness after furfural carbonization. Additionally, the lateral and longitudinal etching paths of the laser beam are clearly visible, with an ordered array of square structures forming at their intersections. Each individual square structure resembles a swimming pool, with the framework structure forming the walls and the exposed Al substrate at the bottom. Water diffuses within the grooves surrounding the square structures, rising upwards along the framework under capillary action. This structure is similar to salt pans on the coast, dividing the seawater and facilitating evaporation. Under high magnification, the rough, velvety, broccoli-like nanostructures on the L-Al surface appear smooth.

[0056] From our prepared samples, we found that C@L-Al-1 was brownish-black, and the prepolymerized furfural on the surface did not undergo good carbonization. The Al substrate has a low melting point; carbonization at 800℃ resulted in melting of the Al substrate and severe distortion of the sample, which is detrimental to the large-scale production and application of C@L-Al-3. Therefore, in subsequent experiments, we chose C@L-Al-2, prepared at 700℃, as the light absorber and evaporator for the evaporator.

[0057] Figure 2 This paper presents the mass loss curves over time of an evaporation system using C@L-Al-2 to test the evaporation performance of simulated seawater at concentrations of 3.5 wt%, 10.0 wt%, and 15.0 wt% under one solar radiation intensity. The results show that the evaporation rate decreases with increasing solution concentration. This is because the increase in solute in the solution leads to increased osmotic pressure and surface tension, making it difficult for water molecules to escape from the solution.

[0058] like Figure 3As shown, the desalination rates of C@L-Al-2 for 3.5 wt%, 10.0 wt%, and 15.0 wt% simulated seawater were 2.12 kg m³. -2 h -1 1.78 kg m -2 h -1 and 1.69 kg m -2 h -1 Their energy utilization efficiencies are 91.8%, 73.7%, and 69.4%, respectively. In traditional water supply modes, salt deposition in evaporation systems begins at the center of the evaporator and spreads towards the edges. This indicates that the concentrated brine at the center of the evaporator surface is more likely to reach saturation. Therefore, diverting this easily saturated concentrated brine from the evaporator surface can effectively solve the salt deposition problem. To demonstrate the universality of the concentrated brine diversion mode evaporator system and the long-term operational stability of C@L-Al-2, this invention uses C@L-Al-2 to desalinate 3.5wt% simulated seawater for 8 hours under 1 solar radiation intensity. Figure 4 The evaporation rate variation during this process was recorded, and optical photographs of the C@L-Al-2 surface were taken from the start to the end of the experiment. The results show that the evaporation rate during this process is approximately 1.97 kg m³. -2 h -1 Up to 2.15 kg m - 2 h -1 The evaporation rate fluctuated between these values, with an average evaporation rate of 2.09 kg m³. -2 h -1 This means that C@L-Al-2 can maintain stable and efficient operation during long-term evaporation. Figure 4 No salt deposition was observed on the C@L-Al-2 surface, indicating that the water supply method using concentrated brine diversion mode, in which high-concentration brine concentrated by evaporation is diverted to the recovery device and low-concentration brine is pumped to the C@L-Al-2 surface by siphon action, can still achieve excellent salt barrier performance.

[0059] To ensure a long service life, an evaporation test was conducted for 8 hours daily for 15 days using 3.5 wt% simulated seawater desalinated at one solar intensity. The change in evaporation rate during this process was recorded. Figure 5 During the 15-day test, the maximum daily average evaporation rate was 2.17 kg m³. -2 h -1 The minimum value is 1.96 kg m -2 h -1 Its average evaporation rate is 2.12 kg m³. -2 h -1The fluctuations in evaporation rate may be caused by fluctuations in factors such as humidity and ambient temperature. However, the results of the 15-day test show that the evaporation rate remained stable, and the evaporation performance did not deteriorate, demonstrating excellent evaporation stability.

[0060] In summary, this invention improves the evaporator structure, enhancing its photothermal conversion efficiency and evaporation rate. By combining a concentrated brine drainage mode, a high-performance interfacial solar evaporation system with excellent salt-barrier properties and stable, efficient operation during long-term evaporation is achieved. Specifically, using L-Al as a substrate, a periodic groove structure is formed on the Al sheet surface through laser etching. This micro-network structure not only optimizes the distribution of photothermal conversion materials and opens channels for effective water diffusion and rapid steam dissipation through the groove design, but also provides stable sites for furfural carbonization. Combined with furfural carbon's excellent photothermal conversion capability, hydrophilic properties, and enthalpy reduction mechanism, a significant improvement in photothermal conversion efficiency and evaporation rate is achieved. Furthermore, by combining a concentrated brine drainage mode, a high-performance interfacial solar evaporation system with excellent salt-barrier properties and stable, efficient operation during long-term evaporation is obtained.

Claims

1. A method for preparing an aluminum-based carbon film photothermal evaporator, characterized in that, The specific preparation method is as follows: Laser etching is performed on the surface of an Al sheet to obtain an Al sheet with a periodic groove structure on the surface, resulting in product 1; Oxalic acid and furfural are mixed in a molar ratio of 0.01 to 0.011 to obtain furfural oxalic acid solution. The furfural oxalic acid solution is dropped onto the periodic groove structure on the surface of product 1 until a uniform liquid film is formed on the periodic groove structure on the surface of product 1 to obtain product 2. Product 2 was prepolymerized and carbonized to obtain product 3; Activate the hydrophilic sites of product 3 to obtain an aluminum-based carbon film photothermal evaporator; The carbonization process specifically involves placing the prepolymerized product 2 under a protective atmosphere and carbonizing it at a temperature of 500℃~800℃ to obtain product 3.

2. The method for preparing an aluminum-based carbon film photothermal evaporator according to claim 1, characterized in that, In the step of laser etching on the surface of an Al sheet to obtain an Al sheet with a periodic groove structure on the surface, resulting in product 1, the specific details are as follows: The laser etching range is 2.5 cm × 3.0 cm, the laser spot diameter is 0.05 mm, the laser focal length is 11.0 cm, the spacing between laser beams is 0.1 mm to 0.2 mm, the laser beam scanning path is vertical, and the etching path includes horizontal and vertical directions.

3. The method for preparing an aluminum-based carbon film photothermal evaporator according to claim 2, characterized in that, In the step of laser etching on the surface of an Al sheet to obtain an Al sheet with a periodic groove structure on the surface, resulting in product 1, the specific details are as follows: The periodic groove structure is a square array composed of multiple square groove structures formed by the intersection of horizontal and vertical etching paths.

4. The method for preparing an aluminum-based carbon film photothermal evaporator according to claim 1, characterized in that, In the step of prepolymerizing and carbonizing product 2 to obtain product 3, specifically: Product 2 was dried at 90 °C for 48 h for prepolymerization.

5. The method for preparing an aluminum-based carbon film photothermal evaporator according to claim 4, characterized in that, The flow rate under the protective atmosphere shall not exceed 50 sccm.

6. An aluminum-based carbon film photothermal evaporator, characterized in that, It is prepared by any one of claims 1 to 5.

7. An ISE system, characterized in that, The aluminum-based carbon film photothermal evaporator described in claim 6 is used as the photothermal absorption layer.

8. An ISE system according to claim 7, characterized in that, Based on the concentrated brine diversion mode, a water supply channel and a concentrated brine diversion channel are set on the aluminum-based carbon film photothermal evaporator. The two sides of the aluminum-based carbon film photothermal evaporator are in contact with the head of the water supply channel, and the tail of the water supply channel is in contact with water to supply water to the aluminum-based carbon film photothermal evaporator. The two opposite outer sides of the water supply channel on the aluminum-based carbon film photothermal evaporator are in contact with the head of the concentrated brine diversion channel, and the tail of the concentrated brine diversion channel is connected to the concentrated brine recovery device.

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