A silver-copper bimetallic electrothermal layer coupled solar interface evaporation system, a preparation method and use thereof

Abstract

The present application relates to a kind of silver copper bimetallic electrothermal layer coupling solar interface evaporation system and preparation method and use, the system is composed of photo-thermal layer and electrothermal layer, the photo-thermal layer is with basalt fabric as substrate, by dipping method on basalt fabric load photo-thermal conversion material carbon black and is prepared;The electrothermal layer with basalt fabric as substrate, after pretreatment, sensitization and activation, by dipping method load silver copper nanoparticles and are formed.The photo-thermal layer and electrothermal layer are placed in interface evaporation system by the way of stacking, for brackish water / seawater desalination.It has the advantages such as simple process, good electrically conductive and thermally conductive performance, excellent salt resistance, etc., under one solar intensity and 1.5 V voltage, 7.69 kg·m ‑2 · h ‑1 Actual brackish water evaporation rate, the water after desalination reaches world health organization drinking water standard.Provide innovative and feasible path for solving global freshwater resource crisis, has wide application potential in brackish water purification, seawater desalination.

Description

Technical Field

[0001] This invention relates to the field of brackish water / seawater desalination technology, specifically to a silver-copper bimetallic electrothermal layer coupled solar energy interface evaporation system, its preparation method, and its applications. Background Technology

[0002] The global freshwater shortage is becoming increasingly severe, with climate change, population growth, and the continued rise in industrial water demand further exacerbating the water crisis. Against this backdrop, seawater desalination technology has become a crucial means of alleviating freshwater scarcity. However, traditional seawater desalination technologies, such as reverse osmosis and multi-effect distillation, generally suffer from high energy consumption, high operating costs, strong dependence on infrastructure, and environmental pollution caused by concentrated brine discharge, severely limiting their application and promotion in remote and resource-scarce areas.

[0003] In recent years, solar-driven interfacial evaporation technology has attracted widespread attention due to its low carbon footprint, low energy consumption, and good sustainability. This technology uses solar energy as the sole energy input, relying on photothermal conversion materials to convert light energy into heat energy, achieving localized, efficient heating and rapid evaporation at the gas-liquid interface, thereby significantly improving energy utilization efficiency. Currently commonly used photothermal conversion materials mainly include plasma-enhanced metal materials, semiconductor materials, polymers, and carbon-based materials. Among these, carbon-based materials are widely used in the construction of solar interfacial evaporation devices due to their wide availability, strong light absorption capacity, and low cost. For example, Chinese patent CN202310900796.5 discloses an evaporator prepared by dispersing carbon black, carbon nanotubes, and glutaraldehyde in a polyvinyl alcohol solution, forming a film through filtration, and crosslinking it in hydrochloric acid. This evaporator achieved a yield of 2.62 kg·m³ of 3.5 wt% sodium chloride solution under an irradiance equivalent to two solar irradiances. -2 · h -1 Evaporation rate.

[0004] While carbon-based photothermal materials have shown great potential in constructing high-performance solar evaporators, the fact that most parts of the world experience darkness or low light conditions for most of the time leads to a significant decrease in the evaporation performance of solar interfacial evaporators in real-world environments. Therefore, it is necessary to overcome the dependence of solar evaporation technology on light conditions by coupling with other auxiliary energy sources, enabling continuous, all-weather freshwater production. Electricity, due to its wide availability (such as hydropower, thermal power, tidal power, and solar photovoltaic) and stable supply, is considered an ideal complementary energy source. Introducing electric drive not only improves the system's weather adaptability but also helps to improve overall energy efficiency.

[0005] In nature, silver, copper, and gold are the best electrical conductors. While silver boasts excellent conductivity and antibacterial properties, it is expensive. Copper is cheaper and more abundant, but it oxidizes easily in air, especially in the desalination environment of seawater where current, moisture, salt, and oxygen coexist, leading to corrosion and a decrease in the conductivity of the electrothermal layer, thus affecting evaporation performance. Chinese patent CN202210281260.5 discloses a copper nanowire electrothermal fabric coated with a polyvinyl alcohol / waterborne polyurethane protective layer, which can delay oxidation and shedding to some extent, but its surface temperature still shows a significant decrease with increasing usage cycles. To address these issues, this invention proposes combining the excellent photothermal conversion properties of carbon black with the electrothermal properties of silver and copper nanoparticles. Using basalt fabric as a substrate, photothermal and electrothermal functional layers are constructed through an impregnation coating process, and a water storage structure and insulation layer are integrated, ultimately forming a photoelectric and thermally coupled basalt fabric-based interface evaporation system for the desalination of brackish water and seawater. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a silver-copper bimetallic electrothermal layer coupled solar interface evaporation system, its preparation method, and its applications. This system comprises a photothermal layer and an electrothermal layer. The photothermal layer is prepared by loading carbon black, a photothermal conversion material, onto a basalt fabric substrate using an impregnation method. The electrothermal layer is prepared by loading silver-copper nanoparticles onto the surface of a basalt fabric substrate after pretreatment, sensitization, and activation using an impregnation method. Finally, the photothermal layer and the electrothermal layer are stacked in an interface evaporation system for brackish water / seawater desalination. This system offers advantages such as simple process, resistance to seawater corrosion, good antibacterial properties, excellent water transport performance, good electrical and thermal conductivity, and excellent salt resistance. It overcomes the limitations of traditional solar interface technologies, such as low efficiency and reliance on sunlight, achieving continuous water production around the clock. This provides an innovative and feasible technological path to solving the global freshwater resource crisis and has broad application potential in brackish water purification and seawater desalination.

[0007] The present invention discloses a silver-copper bimetallic electrothermal layer coupled solar interface evaporation system, which consists of a solar panel (1), a battery (2), a DC power supply (3), wires with alligator clips (4), an electrothermal layer (5), a sealing layer (6), a photothermal layer (7), a water delivery layer (8), a collector (9), a faucet (10), a water storage tank (11), and a heat insulation layer (12). The solar panel (1) is connected to the battery (2), which converts light energy into electrical energy and stores it in the battery. The battery (2) is connected to the DC power supply (3), which is connected to the electrothermal layer (5) through wires with alligator clips (4). The DC power supply controls the voltage, and the battery (2) provides energy to the electrothermal layer (5) so that the electrothermal layer generates Joule heat, thereby accelerating the desalination rate of water. A sealing layer (6) is provided above the electrothermal layer (5) to prevent the generated water vapor from escaping upwards. A photothermal layer (7) is provided above the sealing layer (6) to convert light energy into electrical energy. The water is efficiently converted into heat energy, further accelerating the seawater desalination process. A water conveying layer (8) is provided below the electric heating layer (5), and a collector (9) is provided below the water conveying layer (8). A faucet (10) is provided on one side of the collector (9) to facilitate users to collect the fresh water stored in the collector. One end of the water conveying layer (8) is placed in the water storage tank (11), and the seawater stored in the water storage tank (11) is transported to the electric heating layer (5) through capillary action. Under the combined action of Joule heating and photothermal heating, the water is heated. Vaporization produces water vapor, which escapes downwards to the collector (9) due to the barrier effect of the sealing layer (6), and condenses into water droplets in the collector; the water storage tank (11) is provided with a heat insulation layer (12) to reduce heat loss in the system and improve energy utilization efficiency; the sealing layer (6) is made of silicone rubber, the water delivery layer (8) is made of hydrophilic cotton towel, the collector (9) and the water storage tank (11) are both made of graphite, and the heat insulation layer (12) is made of polystyrene foam.

[0008] The method for preparing a silver-copper bimetallic electrothermal layer coupled solar energy interface evaporation system, wherein the evaporation system consists of two parts: a photothermal layer and an electrothermal layer, is carried out according to the following steps: Photothermal layer preparation: a. Pretreatment of basalt fabric: First, wash the basalt fabric with ultrapure water and anhydrous ethanol in sequence. After air drying, immerse the middle part of the fabric in a solution with a concentration of 1-3 mol·L⁻¹. -1 After sealing the fabric in a sodium hydroxide solution, place it in an oven at 80-100 ℃ for 2-4 hours. After removing the fabric, repeatedly wash the fabric surface with ultrapure water until the washing solution is neutral, and then dry it at 60 ℃ for 1 hour. b. Preparation of carbon black dispersion: Weigh 0.033-0.166 g of cetyltrimethylammonium bromide and dissolve it in 100 mL of ultrapure water. Place the solution in an ultrasonic cleaner for ultrasonic dispersion until the cetyltrimethylammonium bromide is completely dissolved. Add 0.1-0.5 g of sodium alginate and continue ultrasonic dispersion until uniform. Then add 0.1-0.5 g of carbon black and ultrasonically disperse while stirring for 1 min, and continue ultrasonication for 15 min to obtain a preliminary dispersion. Place the preliminary dispersion in a 150 W ultrasonic cell disruptor and disperse for 1 h to obtain a carbon black dispersion. c. Preparation of the photothermal layer: Pour the carbon black dispersion obtained in step b into a square petri dish. Immerse each side of the central part of the basalt fabric treated in step a in the carbon black dispersion for 2 min, then place it in an oven at 85℃ to dry. Repeat the immersion and drying process 5 times. Afterward, place the dried fabric in a 0.1-1 mol·L⁻¹ solution. -1 In a calcium chloride solution for 6-18 hours, Ca... 2+ The basalt fabric was cross-linked with sodium alginate, and then dried at 60°C for 1 h to obtain a photothermal layer. Preparation of the heating layer: d. Basalt fabric pretreatment: Immerse the basalt fabric in a 5-7.5 mM potassium hydroxide solution in an oil bath at 60-90 ℃ for 5-7 min, then rinse with ultrapure water to remove residual potassium hydroxide; dry at 90-120 ℃ for 0.5-1.5 h; then, immerse the alkali-treated basalt fabric in a sensitizer solution prepared with 2.5 g stannous chloride, 3.75 mL hydrochloric acid and 125 mL ultrapure water for 20-40 min, then rinse with ultrapure water; immerse the sensitized basalt fabric in an activator solution prepared with 1.5 g silver nitrate and 350 mL ultrapure water for 20-40 min, rinse with ultrapure water, and dry at 80 ℃ for 1 h. e. Preparation of silver-copper nanoparticles: Accurately weigh 1.25 g of copper sulfate pentahydrate, 0.85 g of silver nitrate, and 0.1 g of citric acid, and add them to a solution prepared by mixing 50 mL of ethylene glycol and 25 mL of ultrapure water to prepare a mixture of copper and silver salts. Stir at room temperature for 20-40 min to completely dissolve the solids. Simultaneously, dissolve 2.25 g of ascorbic acid in 50 mL of ethylene glycol solution. After complete dissolution, add 50 mL of ascorbic acid solution to the mixture containing copper and silver salts, and continue stirring at room temperature for 0.5-1.5 h. After the reaction is complete, centrifuge the mixture at 10000 rpm for 5-15 min to obtain silver-copper nanoparticles. Wash the centrifuged product with ultrapure water and ethanol, and then separate it by centrifuging at 10000 rpm for 5-15 min to obtain a silver-gray silver-copper bimetallic product. Dry the product at 40-60℃ for 8-16 h to obtain silver-copper nanoparticles. f. Preparation of the electrothermal layer: Weigh 0.5 g of the silver-copper nanoparticles prepared in step e and add them to 20 mL of ethylene glycol solution. Disperse the nanoparticles by ultrasonication for 0.5-1.5 h. Immerse the basalt fabric pretreated in step d in the solution and dry it at 120-180 ℃. Repeat this process 4-5 times. Then immerse the fabric in a mixture of 18 g of poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) and 1 g of dimethyl sulfoxide for 1 min. Dry it at room temperature for 0.5-1.5 h and then vacuum dry it at 40-60 ℃ for 8-16 h to obtain the electrothermal layer.

[0009] The application of the silver-copper bimetallic electrothermal layer coupled solar interface evaporation system in the preparation of desalinated brackish water / seawater.

[0010] The silver-copper bimetallic electrothermal layer coupled solar interface evaporation system described above has significant application value in the field of brackish water / seawater desalination. It can efficiently desalinate brackish water or seawater to obtain high-quality fresh water, providing an innovative and effective technical approach to solving the problem of water shortage.

[0011] The advantages of this invention compared to the prior art are: (1) The photothermal layer of the present invention is loaded with carbon black, and the electrothermal layer is loaded with copper and silver nanoparticles, respectively realizing efficient photothermal and electrothermal conversion. The synergistic effect of Joule heat and light energy forms a strong heating effect, which significantly improves the water evaporation rate. (2) The present invention uses basalt fabric as a base, which has high mechanical strength and corrosion resistance. At the same time, the silver-copper nanoparticles have antibacterial properties, can adapt to complex marine environments, and extend the service life of the equipment. (3) The present invention converts light energy into electrical energy through solar panels and stores surplus energy in batteries, reducing dependence on traditional energy sources. At the same time, the electrothermal layer only requires a small amount of electrical energy to operate stably, thus reducing overall energy consumption. (4) The present invention overcomes the limitation of traditional interfacial evaporation technology relying on light by the synergistic effect of the photothermal layer and the electrothermal layer, and can continue to operate efficiently even in dark or low light conditions, thereby improving desalination efficiency. (5) Under the combined influence of one solar radiation intensity and a voltage of 1.5 V, the evaporation rate of pure water in the silver-copper bimetallic electrothermal layer coupled solar interface evaporation system constructed in this invention is 8.66 kg·m³. -2 · h -1 The actual evaporation rate of brackish water is 7.69 kg·m³. -2 · h -1 . Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the silver-copper bimetallic electrothermal layer coupled solar energy interface evaporation system of the present invention; Figure 2 This is the process for preparing the photothermal layer of the present invention; Figure 3 The process for preparing the electrothermal layer of this invention is as follows; Figure 4 Scanning electron microscope images of (A) original basalt fabric, (B) basalt fabric loaded with 0.4 wt% carbon black, (C) basalt fabric loaded with 0.5 wt% carbon black, (D) basalt fabric sensitized and activated, (E) basalt fabric loaded with silver-copper nanoparticles and (F) basalt fabric loaded with silver-copper nanoparticles coated with poly(3,4-ethylenedioxythiophene). Figure 5 The changes in mass loss of (A) pure water and (B) brackish water under a solar radiation intensity for the photothermal layers with different carbon black concentrations prepared for this invention. Figure 6 The silver-copper bimetallic electrothermal layer coupled solar interface evaporation system prepared for this invention shows the changes in (A) mass loss of pure water and (B) mass loss of brackish water under a solar light intensity of +1.5V. Figure 7 The silver-copper bimetallic electrothermal layer coupled with solar energy interface evaporation system constructed for this invention shows the changes in the concentrations of four ions before and after treating actual brackish water. Detailed Implementation

[0013] The present invention will be further described below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but they are merely preferred embodiments and do not limit the present invention in any way. Therefore, all equivalent changes made in accordance with the features and principles described in the scope of the present invention are included within the scope of the present invention.

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Example 1

[0015] This invention discloses a silver-copper bimetallic electrothermal layer coupled solar interface evaporation system. The system comprises a solar panel 1, a battery 2, a DC power supply 3, wires 4 with alligator clips, an electrothermal layer 5, a sealing layer 6, a photothermal layer 7, a water delivery layer 8, a collector 9, a faucet 10, a water storage tank 11, and an insulation layer 12. The solar panel 1 is connected to the battery 2, converting solar energy into electrical energy and storing it in the battery. The battery 2 is connected to the DC power supply 3, which is connected to the electrothermal layer 5 via wires 4 with alligator clips. The DC power supply controls the voltage, and the battery 2 provides energy to the electrothermal layer 5, enabling it to generate Joule heat and accelerate the desalination rate. A sealing layer 6 is positioned above the electrothermal layer 5 to prevent water vapor from escaping upwards. A photothermal layer 7 is positioned above the sealing layer 6, efficiently converting solar energy into electrical energy. Thermal energy further accelerates the seawater desalination process. Below the heating layer 5 is a water conveying layer 8, and below the water conveying layer 8 is a collector 9. A faucet 10 is located on one side of the collector 9 for easy access to the fresh water stored in it. One end of the water conveying layer 8 is placed in a water storage tank 11, and seawater stored in the tank is transported to the heating layer 5 via capillary action. Under the combined action of Joule heating and photothermal heat, the water is heated and vaporized to produce water vapor. Due to the barrier effect of the sealing layer 6, the water vapor escapes downwards to the collector 9, where it condenses into water droplets. A heat insulation layer 12 is provided above the water storage tank 11 to reduce heat loss within the system and improve energy utilization efficiency. The sealing layer 6 is made of silicone rubber, the water conveying layer 8 is made of hydrophilic cotton, the collector 9 and the water storage tank 11 are both made of graphite, and the heat insulation layer 12 is made of polystyrene foam. The evaporation system consists of two parts: a photothermal layer and an electrothermal layer. The specific operation is carried out according to the following steps: Photothermal layer preparation: a. Basalt fabric pretreatment: First, wash the basalt fabric with ultrapure water and anhydrous ethanol sequentially. After air drying, immerse the middle part of the fabric in a solution with a concentration of 1 mol·L⁻¹. -1 After sealing the fabric in a sodium hydroxide solution, the fabric was placed in an oven at 100 °C for 4 hours. After removing the fabric, the surface of the fabric was repeatedly washed with ultrapure water until the washing solution was neutral, and then dried at 60 °C for 1 hour. b. Preparation of carbon black dispersion: Weigh 0.033 g of cetyltrimethylammonium bromide and dissolve it in 100 mL of ultrapure water. Place the solution in an ultrasonic cleaner for ultrasonic dispersion until the cetyltrimethylammonium bromide is completely dissolved. Add 0.1 g of sodium alginate and continue ultrasonic dispersion until uniform. Add 0.1 g of carbon black and stir while ultrasonic dispersion for 1 min, then continue ultrasonic dispersion for 15 min to obtain a preliminary dispersion. Place the preliminary dispersion in a 150 W ultrasonic cell disruptor for 1 h to obtain a carbon black dispersion. c. Preparation of the photothermal layer: Pour the carbon black dispersion obtained in step b into a square petri dish. Immerse each side of the central part of the basalt fabric treated in step a in the carbon black dispersion for 2 min, then place it in an oven at 85℃ to dry. Repeat the immersion and drying process 5 times. Afterward, place the dried fabric in a 0.1-1 mol·L⁻¹ solution. -1 In a calcium chloride solution for 6 hours, Ca... 2+ The basalt fabric was cross-linked with sodium alginate, and then dried at 60°C for 1 h to obtain a photothermal layer. Preparation of the heating layer: d. Basalt fabric pretreatment: First, the basalt fabric was immersed in a 5 mM potassium hydroxide solution in an oil bath at 90 ℃ for 7 min, then rinsed with ultrapure water to remove residual potassium hydroxide; and dried at 90 ℃ for 1.5 h. Then, the alkali-treated basalt fabric was immersed in a sensitizer solution prepared with 2.5 g stannous chloride, 3.75 mL hydrochloric acid and 125 mL ultrapure water for 20 min, and then rinsed with ultrapure water. The sensitized basalt fabric was then immersed in an activator solution prepared with 1.5 g silver nitrate and 350 mL ultrapure water for 20 min, rinsed with ultrapure water, and dried at 80 ℃ for 1 h. e. Preparation of silver-copper nanoparticles: Accurately weigh 1.25 g of copper sulfate pentahydrate, 0.85 g of silver nitrate, and 0.1 g of citric acid, and add them to a solution prepared by mixing 50 mL of ethylene glycol and 25 mL of ultrapure water to prepare a mixture of copper and silver salts. Stir at room temperature for 20 min to completely dissolve the solids. Simultaneously, dissolve 2.25 g of ascorbic acid in 50 mL of ethylene glycol solution. After complete dissolution, add 50 mL of ascorbic acid solution to the mixture containing copper and silver salts, and continue stirring at room temperature for 0.5 h. After the reaction is complete, centrifuge the mixture at 10000 rpm for 5-15 min to obtain silver-copper nanoparticles. Wash the centrifuged product with ultrapure water and ethanol, and then separate it by centrifuging at 10000 rpm for 5 min to obtain a silver-gray silver-copper bimetallic product. Dry the product at 40℃ for 16 h to obtain silver-copper nanoparticles. f. Preparation of the electrothermal layer: Weigh 0.5 g of the silver-copper nanoparticles prepared in step e and add them to 20 mL of ethylene glycol solution. Disperse the nanoparticles by ultrasonication for 0.5 h. Immerse the basalt fabric pretreated in step d in the solution and dry it at 120 °C to deposit the silver / copper nanoparticles on the surface of the basalt fabric. Repeat this process 4 times. Then immerse the fabric in a mixture of 18 g of poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) and 1 g of dimethyl sulfoxide for 1 min. Dry it at room temperature for 0.5 h and then vacuum dry it at 40 °C for 16 h to obtain the electrothermal layer.

[0016] The silver-copper bimetallic electrothermal layer coupled solar interface evaporation system achieved 1.72 kg·m³ under one solar radiation intensity. -2 · h -1 The evaporation rate of pure water is 1.63 kg·m -2 · h -1 The evaporation rate of brackish water; the silver-copper bimetallic electrothermal layer coupled solar interface evaporation system achieved 8.28 kg·m³ under one solar radiation intensity and a voltage of 1.5 V. -2 · h -1 The pure water evaporation rate and 7.06 kg·m -2 · h -1 The evaporation rate of brackish water. Example 2

[0017] The silver-copper bimetallic electrothermal layer coupled solar interface evaporation system is implemented according to Example 1; The evaporation system consists of two parts: a photothermal layer and an electrothermal layer. The specific operation is as follows: Photothermal layer preparation: a. Pretreatment of basalt fabric: First, wash the basalt fabric with ultrapure water and anhydrous ethanol in sequence. After air drying, immerse the middle part of the fabric in a solution with a concentration of 1.5 mol·L⁻¹. -1 The fabric was sealed in a sodium hydroxide solution and then placed in an oven at 85 °C for 2.5 h. After removing the fabric, the surface of the fabric was repeatedly washed with ultrapure water until the washing solution was neutral, and then dried at 60 °C for 1 h. b. Preparation of carbon black dispersion: Weigh 0.066 g of cetyltrimethylammonium bromide and dissolve it in 100 mL of ultrapure water. Place the solution in an ultrasonic cleaner for ultrasonic dispersion until the cetyltrimethylammonium bromide is completely dissolved. Add 0.2 g of sodium alginate and continue ultrasonic dispersion until uniform. Add 0.2 g of carbon black and ultrasonically disperse while stirring for 1 min, then continue ultrasonication for 15 min to obtain a preliminary dispersion. Place the preliminary dispersion in a 150 W ultrasonic cell disruptor and disperse for 1 h to obtain a carbon black dispersion. c. Preparation of the photothermal layer: Pour the carbon black dispersion obtained in step b into a square petri dish. Immerse each side of the central part of the basalt fabric treated in step a in the carbon black dispersion for 2 min, then place it in an oven at 85℃ to dry. Repeat the immersion and drying process 5 times. Afterward, place the dried fabric in a 0.1-1 mol·L⁻¹ solution. -1 In a calcium chloride solution for 9 hours, Ca... 2+ The basalt fabric was cross-linked with sodium alginate, and then dried at 60°C for 1 h to obtain a photothermal layer. Preparation of the heating layer: d. Basalt fabric pretreatment: First, the basalt fabric was immersed in a 5.5 mM potassium hydroxide solution in an oil bath at 70 ℃ for 6 min, then rinsed with ultrapure water to remove residual potassium hydroxide; and dried at 100 ℃ for 1.0 h. Then, the alkali-treated basalt fabric was immersed in a sensitizer solution prepared with 2.5 g stannous chloride, 3.75 mL hydrochloric acid and 125 mL ultrapure water for 25 min, and then rinsed with ultrapure water. The sensitized basalt fabric was then immersed in an activator solution prepared with 1.5 g silver nitrate and 350 mL ultrapure water for 25 min, rinsed with ultrapure water, and dried at 80 ℃ for 1 h. e. Preparation of silver-copper nanoparticles: Accurately weigh 1.25 g of copper sulfate pentahydrate, 0.85 g of silver nitrate, and 0.1 g of citric acid, and add them to a solution prepared by mixing 50 mL of ethylene glycol and 25 mL of ultrapure water to prepare a mixture of copper and silver salts. Stir at room temperature for 25 min to completely dissolve the solids. Simultaneously, dissolve 2.25 g of ascorbic acid in 50 mL of ethylene glycol solution. After complete dissolution, add 50 mL of ascorbic acid solution to the mixture containing copper and silver salts, and continue stirring at room temperature for 0.75 h. After the reaction is complete, centrifuge the mixture at 10,000 rpm for 7 min to obtain silver-copper nanoparticles. Wash the centrifuged product with ultrapure water and ethanol, and then separate it by centrifuging at 10,000 rpm for 7 min to obtain a silver-gray silver-copper bimetallic product. Dry the product at 45℃ for 10 h to obtain silver-copper nanoparticles. f. Preparation of the electrothermal layer: Weigh 0.5 g of the silver-copper nanoparticles prepared in step e and add them to 20 mL of ethylene glycol solution. Disperse the nanoparticles by ultrasonication for 0.5-1.5 h. Immerse the basalt fabric pretreated in step d in the solution and dry it at 130 °C to deposit the silver / copper nanoparticles on the surface of the basalt fabric. Repeat this process 5 times. Then immerse the fabric in a mixture of 18 g of poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) and 1 g of dimethyl sulfoxide for 1 min. Dry it at room temperature for 0.75 h and then vacuum dry it at 50 °C for 14 h to obtain the electrothermal layer.

[0018] The aforementioned silver-copper bimetallic electrothermal layer coupled solar interface evaporation system achieved 1.84 kg·m³ evaporation under one solar radiation intensity. -2 · h -1 The pure water evaporation rate and 1.72 kg·m -2 · h -1 The evaporation rate of brackish water; the silver-copper bimetallic electrothermal layer coupled solar interface evaporation system achieved 8.47 kg·m³ under one solar radiation intensity and a combined voltage of 1.5 V. -2 · h -1 The pure water evaporation rate and 7.43 kg·m -2 · h -1 The evaporation rate of brackish water. Example 3

[0019] The silver-copper bimetallic electrothermal layer coupled solar energy interface evaporation system described in this invention is based on Example 1. The evaporation system consists of two parts: a photothermal layer and an electrothermal layer. The specific operation is carried out according to the following steps: Photothermal layer preparation: a. Pretreatment of basalt fabric: First, wash the basalt fabric with ultrapure water and anhydrous ethanol in sequence. After air drying, immerse the middle part of the fabric in a solution with a concentration of 2.5 mol·L⁻¹. -1 After sealing the fabric in a sodium hydroxide solution, the fabric was placed in an oven at 85°C for 2 hours. After removing the fabric, the surface of the fabric was repeatedly washed with ultrapure water until the washing solution was neutral, and then dried at 60°C for 1 hour. b. Preparation of carbon black dispersion: Weigh 0.1 g of hexadecyltrimethylammonium bromide and dissolve it in 100 mL of ultrapure water. Place the solution in an ultrasonic cleaner for ultrasonic dispersion until the hexadecyltrimethylammonium bromide is completely dissolved. Add 0.3 g of sodium alginate and continue ultrasonic dispersion until uniform. Add 0.3 g of carbon black and ultrasonically disperse while stirring for 1 min, then continue ultrasonication for 15 min to obtain a preliminary dispersion. Place the preliminary dispersion in a 150 W ultrasonic cell disruptor for 1 h to obtain a carbon black dispersion. c. Preparation of the photothermal layer: Pour the carbon black dispersion obtained in step b into a square petri dish. Immerse each side of the central part of the basalt fabric treated in step a in the carbon black dispersion for 2 min, then place it in an oven at 85℃ to dry. Repeat the immersion and drying process 5 times. Afterward, place the dried fabric in a 0.1-1 mol·L⁻¹ solution. -1 In a calcium chloride solution for 12 hours, Ca... 2+ The basalt fabric was cross-linked with sodium alginate, and then dried at 60°C for 1 h to obtain a photothermal layer. Preparation of the heating layer: d. Basalt fabric pretreatment: First, immerse the basalt fabric in a 7.0 mM potassium hydroxide solution at a temperature of 80°C. o The basalt fabric was subjected to an oil bath at C for 6 min, followed by rinsing with ultrapure water to remove residual potassium hydroxide on the surface; it was then dried at 110 °C for 1 h; next, the alkali-treated basalt fabric was immersed in a sensitizer solution prepared with 2.5 g stannous chloride, 3.75 mL hydrochloric acid and 125 mL ultrapure water for 35 min, and then rinsed with ultrapure water; the sensitized basalt fabric was then immersed in an activator solution prepared with 1.5 g silver nitrate and 350 mL ultrapure water for 35 min, rinsed with ultrapure water, and then dried at 80 °C for 1 h. e. Preparation of silver-copper nanoparticles: Accurately weigh 1.25 g of copper sulfate pentahydrate, 0.85 g of silver nitrate, and 0.1 g of citric acid, and add them to a solution prepared by mixing 50 mL of ethylene glycol and 25 mL of ultrapure water to prepare a mixture of copper and silver salts. Stir at room temperature for 30 min to completely dissolve the solids. Simultaneously, dissolve 2.25 g of ascorbic acid in 50 mL of ethylene glycol solution. After complete dissolution, add 50 mL of ascorbic acid solution to the mixture containing copper and silver salts, and continue stirring at room temperature for 1.0 h. After the reaction is complete, centrifuge the mixture at 10000 rpm for 12 min to obtain silver-copper nanoparticles. Wash the centrifuged product with ultrapure water and ethanol, and then separate it again by centrifuging at 10000 rpm for 12 min to obtain a silver-gray silver-copper bimetallic product. Heat the product at 55°C. o Silver-copper nanoparticles were obtained by drying at C for 10 h. f. Preparation of the electrothermal layer: Weigh 0.5 g of the silver-copper nanoparticles prepared in step e and add them to 20 mL of ethylene glycol solution. Disperse the nanoparticles by ultrasonication for 1.25 h. Immerse the basalt fabric pretreated in step d in the solution and dry it at 160 °C to deposit the silver / copper nanoparticles on the surface of the basalt fabric. Repeat this process 4 times. Then immerse the fabric in a mixture of 18 g of poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) and 1 g of dimethyl sulfoxide for 1 min. Dry it at room temperature for 1.25 h and then vacuum dry it at 55 °C for 12 h to obtain the electrothermal layer.

[0020] The silver-copper bimetallic electrothermal layer coupled solar interface evaporation system achieved 1.72 kg·m³ under one solar radiation intensity. -2 · h -1 The pure water evaporation rate and 1.69 kg·m -2 · h -1 The evaporation rate of brackish water; the silver-copper bimetallic electrothermal layer coupled solar interface evaporation system achieved 8.36 kg·m³ under one solar radiation intensity and a voltage of 1.5 V. -2 · h -1 The pure water evaporation rate and 7.27 kg·m -2 · h -1 The evaporation rate of brackish water. Example 4

[0021] The silver-copper bimetallic electrothermal layer coupled solar energy interface evaporation system described in this invention is based on Example 1. The evaporation system consists of two parts: a photothermal layer and an electrothermal layer. The specific operation is carried out according to the following steps: Photothermal layer preparation: a. Basalt fabric pretreatment: First, wash the basalt fabric with ultrapure water and anhydrous ethanol sequentially. After air drying, immerse the middle part of the fabric in a solution with a concentration of 2 mol·L⁻¹. -1 After sealing the fabric in a sodium hydroxide solution, the fabric was placed in an oven at 90°C for 3 hours. After removing the fabric, the surface of the fabric was repeatedly washed with ultrapure water until the washing solution was neutral, and then dried at 60°C for 1 hour. b. Preparation of carbon black dispersion: Weigh 0.133 g of hexadecyltrimethylammonium bromide and dissolve it in 100 mL of ultrapure water. Place the solution in an ultrasonic cleaner for ultrasonic dispersion until the hexadecyltrimethylammonium bromide is completely dissolved. Add 0.4 g of sodium alginate and continue ultrasonic dispersion until uniform. Add 0.4 g of carbon black and stir while ultrasonic dispersion for 1 min, then continue ultrasonic dispersion for 15 min to obtain a preliminary dispersion. Place the preliminary dispersion in a 150 W ultrasonic cell disruptor for 1 h to obtain a carbon black dispersion. c. Preparation of the photothermal layer: Pour the carbon black dispersion obtained in step b into a square petri dish. Immerse each side of the central part of the basalt fabric treated in step a in the carbon black dispersion for 2 min, then place it in an oven at 85℃ to dry. Repeat the immersion and drying process 5 times. Afterward, place the dried fabric in a 0.1-1 mol·L⁻¹ solution. -1 In a calcium chloride solution for 15 hours, Ca... 2+ The basalt fabric was cross-linked with sodium alginate, and then dried at 60°C for 1 h to obtain a photothermal layer. Preparation of the heating layer: d. Basalt fabric pretreatment: First, the basalt fabric was immersed in a 6.55 mM potassium hydroxide solution in an oil bath at 75 ℃ for 6 min, then rinsed with ultrapure water to remove residual potassium hydroxide; and dried at 105 ℃ for 1.0 h. Then, the alkali-treated basalt fabric was immersed in a sensitizer solution prepared with 2.5 g stannous chloride, 3.75 mL hydrochloric acid and 125 mL ultrapure water for 30 min, and then rinsed with ultrapure water. The sensitized basalt fabric was then immersed in an activator solution prepared with 1.5 g silver nitrate and 350 mL ultrapure water for 30 min, rinsed with ultrapure water, and dried at 80 ℃ for 1 h. e. Preparation of silver-copper nanoparticles: Accurately weigh 1.25 g of copper sulfate pentahydrate, 0.85 g of silver nitrate, and 0.1 g of citric acid, and add them to a solution prepared by mixing 50 mL of ethylene glycol and 25 mL of ultrapure water to prepare a mixture of copper and silver salts. Stir at room temperature for 30 min to completely dissolve the solids. Simultaneously, dissolve 2.25 g of ascorbic acid in 50 mL of ethylene glycol solution. After complete dissolution, add 50 mL of ascorbic acid solution to the mixture containing copper and silver salts, and continue stirring at room temperature for 1.0 h. After the reaction is complete, centrifuge the mixture at 10000 rpm for 10 min to obtain silver-copper nanoparticles. Wash the centrifuged product with ultrapure water and ethanol, and then separate it by centrifuging at 10000 rpm for 10 min to obtain a silver-gray silver-copper bimetallic product. Dry the product at 50℃ for 12 h to obtain silver-copper nanoparticles. f. Preparation of the electrothermal layer: Weigh 0.5 g of the silver-copper nanoparticles prepared in step e and add them to 20 mL of ethylene glycol solution. Disperse the nanoparticles by ultrasonication for 1.0 h. Immerse the basalt fabric pretreated in step d in the solution and dry it at 150 °C to deposit the silver / copper nanoparticles on the surface of the basalt fabric. Repeat this process 5 times. Then immerse the fabric in a mixture of 18 g of poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) and 1 g of dimethyl sulfoxide for 1 min. Dry it at room temperature for 1.0 h and then vacuum dry it at 55 °C for 13 h to obtain the electrothermal layer.

[0022] The silver-copper bimetallic electrothermal layer coupled solar interface evaporation system achieved 2.03 kg·m³ under one solar radiation intensity. -2 · h -1 The pure water evaporation rate and 1.66 kg·m -2 · h -1 The evaporation rate of brackish water; the silver-copper bimetallic electrothermal layer coupled solar interface evaporation system achieved 8.66 kg·m³ under one solar radiation intensity and a voltage of 1.5 V. -2 · h -1 The pure water evaporation rate and 7.14 kg·m -2 · h -1 The evaporation rate of brackish water. Example 5

[0023] The silver-copper bimetallic electrothermal layer coupled solar energy interface evaporation system described in this invention is based on Example 1. The evaporation system consists of two parts: a photothermal layer and an electrothermal layer. The specific operation is carried out according to the following steps: Photothermal layer preparation: a. Basalt fabric pretreatment: First, wash the basalt fabric with ultrapure water and anhydrous ethanol in sequence. After air drying, immerse the middle part of the fabric in a solution with a concentration of 3 mol·L⁻¹. -1 After sealing the fabric in a sodium hydroxide solution, the fabric was placed in an oven at 80°C for 4 hours. After removing the fabric, the surface of the fabric was repeatedly washed with ultrapure water until the washing solution was neutral, and then dried at 60°C for 1 hour. b. Preparation of carbon black dispersion: Weigh 0.033-0.166 g of cetyltrimethylammonium bromide and dissolve it in 100 mL of ultrapure water. Place the solution in an ultrasonic cleaner for ultrasonic dispersion until the cetyltrimethylammonium bromide is completely dissolved. Add 0.5 g of sodium alginate and continue ultrasonic dispersion until uniform. Add 0.5 g of carbon black and stir while ultrasonic dispersion for 1 min, then continue ultrasonic dispersion for 15 min to obtain a preliminary dispersion. Place the preliminary dispersion in a 150 W ultrasonic cell disruptor and disperse for 1 h to obtain a carbon black dispersion. c. Preparation of the photothermal layer: Pour the carbon black dispersion obtained in step b into a square petri dish. Immerse each side of the central part of the basalt fabric treated in step a in the carbon black dispersion for 2 min, then place it in an oven at 85℃ to dry. Repeat the immersion and drying process 5 times. Afterward, place the dried fabric in a 0.1-1 mol·L⁻¹ solution. -1 In a calcium chloride solution for 18 hours, Ca... 2+ The basalt fabric was cross-linked with sodium alginate, and then dried at 60°C for 1 h to obtain a photothermal layer. Preparation of the heating layer: d. Pretreatment of basalt fabric: First, the basalt fabric was immersed in a 7.5 mM potassium hydroxide solution in an oil bath at 60°C for 5 minutes, followed by rinsing with ultrapure water to remove residual potassium hydroxide. It was then dried at 120°C for 0.5 hours. Next, the alkali-treated basalt fabric was immersed in a sensitizer solution prepared with 2.5 g stannous chloride, 3.75 mL hydrochloric acid, and 125 mL ultrapure water for 40 minutes, and then rinsed thoroughly with ultrapure water. Finally, the sensitized basalt fabric was immersed in an activator solution prepared with 1.5 g silver nitrate and 350 mL ultrapure water for 40 minutes, rinsed thoroughly with ultrapure water, and then dried at 80°C. o Dry at temperature C for 1 h; e. Preparation of silver-copper nanoparticles: Accurately weigh 1.25 g of copper sulfate pentahydrate, 0.85 g of silver nitrate, and 0.1 g of citric acid, and add them to a solution prepared by mixing 50 mL of ethylene glycol and 25 mL of ultrapure water to prepare a mixture of copper and silver salts. Stir at room temperature for 40 min to completely dissolve the solids. Simultaneously, dissolve 2.25 g of ascorbic acid in 50 mL of ethylene glycol solution. After complete dissolution, add 50 mL of ascorbic acid solution to the mixture containing copper and silver salts, and continue stirring at room temperature for 1.5 h. After the reaction is complete, centrifuge the mixture at 10,000 rpm for 15 min to obtain silver-copper nanoparticles. Wash the centrifuged product with ultrapure water and ethanol, and then separate it by centrifuging at 10,000 rpm for 15 min to obtain a silver-gray silver-copper bimetallic product. Dry the product at 60℃ for 16 h to obtain silver-copper nanoparticles. f. Preparation of the electrothermal layer: Weigh 0.5 g of the silver-copper nanoparticles prepared in step e and add them to 20 mL of ethylene glycol solution. Disperse the nanoparticles by ultrasonication for 1.5 h. Immerse the basalt fabric pretreated in step d in the solution and dry it at 180 °C to deposit the silver / copper nanoparticles on the surface of the basalt fabric. Repeat this process 5 times. Then immerse the fabric in a mixture of 18 g of poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) and 1 g of dimethyl sulfoxide for 1 min. Dry it at room temperature for 1.5 h and then vacuum dry it at 60 °C for 8 h to obtain the electrothermal layer.

[0024] The silver-copper bimetallic electrothermal layer coupled solar interface evaporation system described in this invention achieves 1.63 kg·m³ evaporation under one solar radiation intensity. -2 · h -1 The pure water evaporation rate and 1.78 kg·m -2 · h -1 The evaporation rate of brackish water was determined; and an evaporation rate of 8.15 kg·m⁻² was achieved under a combined solar radiation intensity and a voltage of 1.5 V. -2 · h -1 The pure water evaporation rate and 7.69 kg·m -2 · h -1 The evaporation rate of brackish water. Example 6

[0025] Material characterization and desalination performance testing: The photothermal layer is according to Figure 2 The process of preparation, the electrothermal layer is prepared according to... Figure 3 The process involves preparation, followed by assembling the photothermal layer and the electrothermal layer, as follows: Figure 1As shown; and the microstructures of the original basalt fabric, basalt fabric loaded with 0.4 wt% carbon black, basalt fabric loaded with 0.5 wt% carbon black, basalt fabric after sensitization and activation treatment, basalt fabric loaded with silver-copper nanoparticles, and basalt fabric coated with poly(3,4-ethylenedioxythiophene) and loaded with silver-copper nanoparticles were observed by scanning electron microscopy. Figure 4 As shown, it can be observed that when the concentration of carbon black is too high, it forms a shell layer on the basalt fabric, reducing water transport performance and photothermal conversion performance. Then, the evaporation performance of photothermal layers with different carbon black concentrations on pure water under sunlight was tested. Figure 5 As shown, the highest evaporation performance for pure water was achieved at a carbon black concentration of 0.4 wt%, reaching 2.03 kg·m³. -2 · h -1 Therefore, the photothermal layer and electrothermal layer prepared in Example 4 were selected for testing. Under the combined action of one solar intensity radiation and a voltage of 1.5 V, the evaporation rates of this evaporation system for pure water and brackish water were 8.66 kg·m³, respectively. -2 · h -1 and 7.69 kg·m -2 · h -1 See Figure 6 The Na content in brackish water samples before and after desalination was measured by inductively coupled plasma atomic emission spectrometry. + Mg 2+ K + Ca 2+ Concentration changes, such as Figure 7 As shown, the concentrations of the four ions in the treated water decreased by four orders of magnitude, meeting the World Health Organization's drinking water standards.

Claims

1. A silver-copper bimetallic electrothermal layer coupled solar energy interface evaporation system, characterized in that, The system comprises a solar panel, a battery, a DC power supply, wires with alligator clips, an electric heating layer, a sealing layer, a photothermal layer, a water supply layer, a collector, a faucet, a water storage tank, and an insulation layer. The solar panel is connected to the battery, converting solar energy into electrical energy and storing it in the battery. The battery is connected to the DC power supply, which is connected to the electric heating layer via wires with alligator clips. The DC power supply controls the voltage, and the battery provides energy to the electric heating layer. A sealing layer is located above the electric heating layer. A photothermal layer is located above the sealing layer. A water supply layer is located below the electric heating layer, and below the water supply layer is... The system includes a collector with a faucet on one side; one end of the water delivery layer is placed in a water storage tank, where seawater stored in the tank is transported to the heating layer via capillary action. Under the combined action of Joule heating and photothermal heating, the water is heated and vaporized to produce water vapor. Due to the barrier effect of the sealing layer, the water vapor escapes downwards to the collector, where it condenses into water droplets. A heat insulation layer is provided above the water storage tank to reduce heat loss in the system and improve energy utilization efficiency. The sealing layer is made of silicone rubber, the water delivery layer is made of hydrophilic cotton, the collector and the water storage tank are both made of graphite, and the heat insulation layer is made of polystyrene foam. Preparation of the electrothermal layer: d. Basalt fabric pretreatment: Immerse the basalt fabric in a 5-7.5 mM potassium hydroxide solution in an oil bath at 60-90 ℃ for 5-7 min, then rinse with ultrapure water to remove residual potassium hydroxide; dry at 90-120 ℃ for 0.5-1.5 h; then, immerse the alkali-treated basalt fabric in a sensitizer solution prepared with 2.5 g stannous chloride, 3.75 mL hydrochloric acid and 125 mL ultrapure water for 20-40 min, then rinse with ultrapure water; immerse the sensitized basalt fabric in an activator solution prepared with 1.5 g silver nitrate and 350 mL ultrapure water for 20-40 min, rinse with ultrapure water, and dry at 80 ℃ for 1 h. e. Preparation of silver-copper nanoparticles: Accurately weigh 1.25 g of copper sulfate pentahydrate, 0.85 g of silver nitrate, and 0.1 g of citric acid, and add them to a solution prepared by mixing 50 mL of ethylene glycol and 25 mL of ultrapure water to prepare a mixture of copper and silver salts. Stir at room temperature for 20-40 min to completely dissolve the solids. Simultaneously, dissolve 2.25 g of ascorbic acid in 50 mL of ethylene glycol solution. After complete dissolution, add 50 mL of ascorbic acid solution to the mixture containing copper and silver salts, and continue stirring at room temperature for 0.5-1.5 h. After the reaction is complete, centrifuge the mixture at 10000 rpm for 5-15 min to obtain silver-copper nanoparticles. Wash the centrifuged product with ultrapure water and ethanol, and then separate it by centrifuging at 10000 rpm for 5-15 min to obtain a silver-gray silver-copper bimetallic product. Dry the product at 40-60℃ for 8-16 h to obtain silver-copper nanoparticles. f. Preparation of the electrothermal layer: Weigh 0.5 g of the silver-copper nanoparticles prepared in step e and add them to 20 mL of ethylene glycol solution. Disperse the nanoparticles by ultrasonication for 0.5-1.5 h. Immerse the basalt fabric pretreated in step d in the solution and dry it at 120-180℃. Repeat this process 4-5 times. Then immerse the fabric in a mixture of 18 g of poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) and 1 g of dimethyl sulfoxide for 1 min. Dry it at room temperature for 0.5-1.5 h and then vacuum dry it at 40-60℃ for 8-16 h to obtain the electrothermal layer.

2. The silver-copper bimetallic electrothermal layer coupled solar interface evaporation system according to claim 1, characterized in that, The photothermal layer is prepared as follows: a. Basalt fabric pretreatment: First, wash the basalt fabric with ultrapure water and anhydrous ethanol sequentially. After air drying, immerse the middle part of the fabric in a solution with a concentration of 1-3 mol·L⁻¹. -1 After sealing the fabric in a sodium hydroxide solution, place it in an oven at 80-100 ℃ for 2-4 hours. After removing the fabric, repeatedly wash the fabric surface with ultrapure water until the washing solution is neutral, and then dry it at 60 ℃ for 1 hour. b. Preparation of carbon black dispersion: Weigh 0.033-0.166 g of cetyltrimethylammonium bromide and dissolve it in 100 mL of ultrapure water. Place the solution in an ultrasonic cleaner for ultrasonic dispersion until the cetyltrimethylammonium bromide is completely dissolved. Add 0.1-0.5 g of sodium alginate and continue ultrasonic dispersion until uniform. Then add 0.1-0.5 g of carbon black and ultrasonically disperse while stirring for 1 min, and continue ultrasonication for 15 min to obtain a preliminary dispersion. Place the preliminary dispersion in a 150 W ultrasonic cell disruptor and disperse for 1 h to obtain a carbon black dispersion. c. Preparation of the photothermal layer: Pour the carbon black dispersion obtained in step b into a square petri dish. Immerse each side of the central part of the basalt fabric treated in step a in the carbon black dispersion for 2 min, then place it in an oven at 85℃ to dry. Repeat the immersion and drying process 5 times. Afterward, place the dried fabric in a 0.1-1 mol·L⁻¹ solution. -1 In a calcium chloride solution for 6-18 hours, Ca... 2+ The basalt fabric was cross-linked with sodium alginate, and then dried at 60°C for 1 h to obtain a photothermal layer.

3. The use of the silver-copper bimetallic electrothermal layer coupled solar interface evaporation system according to claim 1 in the preparation of desalinated brackish water / seawater.

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