An electrothermal assisted solar interface evaporation system and uses thereof

Abstract

The application discloses an electric heating assisted solar interface evaporation system and application thereof, and belongs to the field of water evaporation technology. The system is composed of a solar interface evaporation composite material and a device. The system combines a high-conductivity stainless steel mesh and a high-water-transporting basalt fiber fabric loaded with polydopamine, carbon nanotubes and polypyrrole, improves the evaporation performance of the material through electric heating-photo-thermal synergistic effect, and is easy to be produced in large scale. The system not only improves the rate of solar-driven interface water evaporation, but also is applicable to all-weather and has a high evaporation rate at night, thereby providing an effective solution to freshwater resource shortage. The system has a wide application prospect in the fields of brackish water desalination, seawater desalination, steam power generation, heat energy collection and industrial salt-containing wastewater purification.

Description

Technical Field

[0001] This invention relates to an electrothermal assisted solar interface evaporation system and its applications. The system possesses both electrothermal and photothermal effects, which can be used synergistically for all-weather brackish water desalination. It also maintains a high evaporation rate at night and can be widely applied to brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification. Background Technology

[0002] Currently, membrane distillation, reverse osmosis, and multi-effect evaporation have been developed for desalination. However, these technologies have problems such as complex operation, large heat loss, high cost, and secondary pollution. Therefore, it is urgent to develop a green and renewable freshwater production technology.

[0003] Solar energy is an inexhaustible energy source, making seawater desalination and wastewater purification based on solar-powered interfacial water evaporation systems a research hotspot. Solar-powered interfacial evaporation systems primarily concentrate heat energy at the gas-liquid interface through photothermal materials, enhancing the photothermal effect. Current research mainly focuses on using various photothermal materials to increase photothermal performance and thus increase heat generation.

[0004] Chinese patent CN202310433382.6 discloses a multilayer composite structure for achieving directional liquid transport and interfacial evaporation, with an evaporation rate as high as 1.61 kg·m³ under a solar intensity. -2 ·h -1 Although its evaporation rate is high under strong sunlight, it is not suitable for cloudy days or winter when sunlight intensity is low and temperature is low, which seriously reduces the yield of freshwater. Therefore, there is an urgent need to develop an all-weather interfacial evaporation device that can be used in various conditions and produce a continuous supply of freshwater 24 hours a day.

[0005] CN202310196555.7 discloses a titanium suboxide-based ceramic fiber composite material, its preparation method, and its application. Titanium suboxide obtained by in-situ carbothermic reduction of titanium oxide fibers can be used as both a photothermal and electrothermal material. However, the preparation of this material requires a large amount of energy, resulting in high production costs, and its electrothermal performance is not good. Therefore, separating the photothermal and electrothermal aspects of the material to prepare a photothermal layer with high photothermal efficiency and an electrothermal layer with high electrical conductivity is economically feasible and the preparation process is simple.

[0006] CN202210712056.4 discloses a photothermal-electrothermal synergistic corrugated paper interface evaporation desalination device and its preparation method. This invention separates the photothermal layer and the electrothermal layer, which not only achieves low-cost material preparation but also obtains a high evaporation rate (up to 3.971 kg·m³ under one solar intensity and 6V voltage conditions). -2·h -1 Although the invention was made on a cloudy day (222.45 W·m). -2 It still has 1.2456 kg·m -2 ·h -1 While achieving a high evaporation rate, it suffers from practical problems such as low electrothermal efficiency of the heating layer, high required voltage, and high energy consumption.

[0007] To address existing problems and the current situation, it is urgent to develop an all-weather, electrothermal-assisted solar interface evaporation system and its applications through photovoltaic complementarity. This system consists of a solar interface evaporation composite material and a device. It utilizes an electrothermal-assisted solar interface evaporation system to increase the evaporation rate, simplify the photothermal and electrothermal layers, and identify a material with high electrothermal efficiency that can generate more heat at a lower output voltage, reducing potential safety issues. This will expand its application in brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing an electrothermal-assisted solar interface evaporation system and its applications. This system comprises a solar interface evaporation composite material and a device. It combines a highly conductive stainless steel mesh with a high-water-carrying basalt fiber fabric loaded with polydopamine, carbon nanotubes, and polypyrrole. Through electrothermal-photothermal synergy, the evaporation performance of the materials is improved. Furthermore, this system is easy to mass-produce, not only increasing the rate of solar-driven interface water evaporation but also being applicable in all weather conditions, maintaining a high evaporation rate even at night. This provides an effective solution to freshwater scarcity and has broad application prospects in brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification.

[0009] The present invention discloses an electrothermal assisted solar interface evaporation system, which comprises a solar interface evaporation composite material and a device, wherein the preparation of the composite material is carried out according to the following steps:

[0010] a. Using a concentration of 1-3 mol·L -1 A sodium hydroxide solution is used to heat-treat basalt fiber fabrics, carbon fiber fabrics, or polyacrylonitrile fiber fabrics at a temperature of 60-120℃ for 1-5 hours.

[0011] b. Place the fiber fabric treated in step a into a solution with a concentration of 1-10 g·L⁻¹ -1 Dopamine hydrochloride and concentrations of 1-100 mmol·L -1The mixture is placed in a solution of trimethylamine hydrochloride with a pH of 8-9, and then shaken in a shaker at a speed of 100-200 rpm and a temperature of 20-40℃ for 24-48 hours to ensure that polydopamine is evenly distributed on the fiber fabric. After the reaction is complete, excess polydopamine on the fiber fabric is washed off, and then the fabric is dried in an oven to obtain the composite material.

[0012] c. Immerse both sides of the composite material treated in step b in a sodium alginate-carbon nanotube dispersion with cetyltrimethylammonium bromide as the surfactant and ultrasonically dispersed for 1-4 minutes, then dry in an oven at 80-100℃. Repeat this process 2-5 times to grow carbon nanotubes in situ on the fiber fabric. Then immerse the composite material in a 0.1-1 mol·L⁻¹ solution. -1 The composite material was obtained by soaking in anhydrous calcium chloride solution for 8-12 hours for crosslinking, washing off excess calcium chloride on the surface, and drying in an oven. The mass ratio of hexadecyltrimethylammonium bromide, carbon nanotubes and sodium alginate was 3:3:1, the concentration of carbon nanotubes was 0.1-0.5wt%, and ultrasonic dispersion was performed using an ultrasonic cell disruptor for 0.5-2 hours at a power of 250W.

[0013] d. Immerse the composite material obtained in step c in a mixture of hydrochloric acid, ferric chloride hexahydrate, and pyrrole monomer for 3-5 hours. Wash away excess polypyrrole from the surface, and then dry it in an oven to obtain the composite material. The volume ratio of the hydrochloric acid and ferric chloride hexahydrate mixture to the pyrrole monomer is 0.5-2.5:1, and the concentration of hydrochloric acid is 1 mol·L⁻¹. -1 The concentration of ferric chloride hexahydrate is 0.1-1 mol·L⁻¹. -1 The concentration of pyrrole monomer is the same as the concentration of ferric chloride hexahydrate;

[0014] e. Cut a stainless steel mesh with the same area as the evaporation region of the composite material prepared in step d, and connect and fix the stainless steel mesh to the composite material obtained in step d using conductive adhesive to obtain the electrothermal assisted solar interface evaporation composite material.

[0015] The solar interface evaporation device involved in the electrothermal assisted solar interface evaporation system is composed of a solar power generation component and an evaporator; the solar power generation component is composed of a solar panel (1) and a solar cell (2), the solar panel (1) is connected to the solar cell (2), the solar panel (1) converts solar energy into electrical energy and stores the electrical energy in the solar cell (2);

[0016] The evaporator is composed of a DC power supply (3), wires (4), a water storage tank (5), a photothermal layer (6), a heat insulation layer (7), and an electric heating layer (8); the solar cell (2) is connected to the DC power supply (3); the DC power supply (3) is connected to the electric heating layer (8) through the wires (4), and the DC power supply (3) controls the required output voltage and current of the electric heating layer (8); the water storage tank (5) is composed of two acrylic glass tanks connected by acrylic glass sheets; the glass sheets of the water storage tank (5) are provided with a photothermal layer (6) and an electric heating layer (8); a heat insulation layer (7) is provided directly above the water storage tank (5);

[0017] The water storage tank (5) is made of plexiglass; the photothermal layer (6) is made of fiber fabric impregnated with polydopamine, carbon nanotubes and polypyrrole; the heat insulation layer (7) is polystyrene foam; the electric heating layer (8) is made of stainless steel mesh;

[0018] The solar panel (1) converts solar energy into electrical energy for storage. The current flows through the conductor (4) through the electrothermal layer (8) to generate heat, and the electric heating simultaneously assists the evaporation of the photothermal layer (6).

[0019] The application of the electrothermal assisted solar interface evaporation system in the fields of brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification.

[0020] The advantages of this invention compared to the prior art are:

[0021] (1) The present invention uses fiber fabric as a substrate to prepare a photothermal layer. Its loose and porous structure not only enables efficient water transport, but its excellent flexibility and elasticity also facilitate folding and transport. By simply impregnating the fiber fabric with photothermal materials, not only can the photothermal performance of the materials be enhanced, but it is also easy to mass-produce.

[0022] (2) The present invention uses stainless steel mesh as the electrothermal layer, which is simple to prepare, inexpensive and has high electrothermal efficiency.

[0023] (3) The electrothermal assisted solar interface evaporation system provided by the present invention not only improves the utilization rate of solar energy and the water evaporation rate through the electrothermal-photothermal synergistic enhancement method, but also realizes the production of fresh water in all weather.

[0024] (4) Under solar intensity, with 1.5V applied to assist photothermal activity, the evaporation rate of simulated brackish water is 3.22 kg·m³. -2 ·h -1 . Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the photothermal layer and electrothermal layer structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of the water storage tank of the present invention;

[0028] Figure 4 Scanning electron microscope images (a)-(e) of the original, pretreated, polydopamine-loaded, polydopamine-loaded carbon nanotube, and polydopamine-loaded carbon nanotube-polypyrrole of this invention;

[0029] Figure 5 This invention illustrates the changes in mass loss during evaporation performance testing using electrothermal, photothermal, and photothermal-electrothermal synergistic effects.

[0030] Figure 6 This invention simulates the changes in the concentrations of four ions before and after brackish water treatment.

[0031] The diagram is labeled as follows: 1-Solar panel, 2-Solar power supply, 3-DC power supply, 4-Wire, 5-Water storage tank, 6-Photothermal conversion layer, 7-Insulation layer, 8-Electrical heating layer. Detailed Implementation

[0032] 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 claims of this patent application are included within the scope of this patent application. Unless otherwise specified, the cleaning solution mentioned in this invention is ultrapure water. Unless otherwise specified, the drying oven used in this invention is used for drying at 60°C for 1 hour. Unless otherwise specified, the embodiments are carried out in an indoor environment with a temperature of 20°C and a humidity of 20%.

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0034] Example 1

[0035] The electrically assisted solar interface evaporation device (see...) Figure 1 The device consists of a solar power generation component and an evaporator; the solar power generation component is composed of a solar panel 1 and a solar cell 2, the solar panel 1 is connected to the solar cell 2, the solar panel 1 converts solar energy into electrical energy and stores the electrical energy in the solar cell 2;

[0036] The evaporator consists of a DC power supply 3, wires 4, a water storage tank 5, a photothermal layer 6, a heat insulation layer 7, and an electric heating layer 8. The solar cell 2 is connected to the DC power supply 3. The DC power supply 3 is connected to the electric heating layer 8 via wires 4, and controls the required output voltage and current of the electric heating layer 8. The water storage tank 5 consists of two acrylic glass tanks connected by acrylic glass sheets. The photothermal layer 6 and the electric heating layer 8 are provided on the glass sheets of the water storage tank 5. A heat insulation layer 7 is provided directly above the water storage tank 5.

[0037] The water storage tank 5 is made of plexiglass; the photothermal layer 6 is made of fiber fabric impregnated with polydopamine, carbon nanotubes, and polypyrrole; the heat insulation layer 7 is polystyrene foam; and the electric heating layer 8 is made of stainless steel mesh.

[0038] The solar panel 1 converts solar energy into electrical energy for storage. The current flows through the conductor 4 through the electrothermal layer 8 to generate heat, and the electric heating simultaneously assists the evaporation of the photothermal layer 6.

[0039] Preparation of the electrothermal assisted solar interface evaporation composite material:

[0040] a. Using a concentration of 2 mol·L -1 A sodium hydroxide solution was used to heat-treat basalt fiber fabric at 90°C for 3 hours.

[0041] b. Place the basalt fiber fabric treated in step a into a solution with a concentration of 1 g·L⁻¹. -1 Dopamine hydrochloride and a concentration of 10 mmol·L -1 The mixture was placed in a solution of trimethylamine hydrochloride with a pH of 8.5, and then shaken in a shaker at 100 rpm and 25°C for 48 hours to ensure that polydopamine was evenly distributed on the fiber fabric. After the reaction was completed, excess polydopamine on the fiber fabric was washed off, and then the fabric was dried in an oven to obtain the composite material.

[0042] c. Immerse both sides of the composite material treated in step b in a sodium alginate-carbon nanotube dispersion with cetyltrimethylammonium bromide as the surfactant and ultrasonically dispersed for 1 min, then dry in an oven at 80℃. Repeat this process 4 times to grow carbon nanotubes in situ on the fiber fabric. Then, place the mixture in an oven with a concentration of 0.1 mol·L⁻¹. -1 The composite material was obtained by soaking in anhydrous calcium chloride solution for 8 hours for crosslinking, washing off excess calcium chloride on the surface, and drying in an oven. The mass ratio of hexadecyltrimethylammonium bromide, carbon nanotubes and sodium alginate was 3:3:1, the concentration of carbon nanotubes was 0.1wt%, and ultrasonic dispersion was performed using an ultrasonic cell disruptor for 0.5 hours at a power of 250W.

[0043] d. The composite material obtained in step c is immersed in a mixture of hydrochloric acid, ferric chloride hexahydrate, and pyrrole monomer for 3 hours. Excess polypyrrole on the surface is washed away, and then the mixture is dried in an oven to obtain the composite material. The volume ratio of the hydrochloric acid and ferric chloride hexahydrate mixture to the pyrrole monomer is 2.4:1, and the concentration of hydrochloric acid is 1 mol·L⁻¹. -1 The concentration of ferric chloride hexahydrate is 0.24 mol·L⁻¹. -1 The concentration of pyrrole monomer is the same as that of ferric chloride hexahydrate.

[0044] e. Cut a 100-mesh stainless steel mesh with the same area as the evaporation zone of the composite material prepared in step d. Connect and fix the stainless steel mesh to the composite material obtained in step d using conductive adhesive. This yields the electrothermal assisted solar interface evaporation composite material, which can be used in brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification.

[0045] Example 2

[0046] The apparatus in the solar interface evaporation system is based on Example 1;

[0047] a. Using a concentration of 1 mol·L -1 A sodium hydroxide solution was used to heat-treat carbon fiber fabric at 120°C for 1 hour.

[0048] b. Place the fiber fabric and carbon fiber fabric treated in step a into a solution with a concentration of 4 g·L⁻¹. -1 Dopamine hydrochloride and a concentration of 1 mmol·L -1 The mixture was placed in a solution of trimethylamine hydrochloride at pH 8, and then shaken in a shaker at 150 rpm and 20°C for 24 hours to ensure that polydopamine was evenly distributed on the fiber fabric. After the reaction was completed, excess polydopamine on the fiber fabric was washed off, and then the fabric was dried in an oven to obtain the composite material.

[0049] c. Immerse both sides of the composite material treated in step b in a sodium alginate-carbon nanotube dispersion containing cetyltrimethylammonium bromide as a surfactant and ultrasonically dispersed for 2 minutes. Then, perform ultrasonic dispersion for 1 hour using an ultrasonic cell disruptor at 250W. Dry in an oven at 90℃. Repeat twice to grow carbon nanotubes in situ on the fiber fabric. Finally, immerse the composite material in a 0.5 mol·L⁻¹ solution. -1 The composite material was obtained by soaking in anhydrous calcium chloride solution for 10 hours for crosslinking, washing off excess calcium chloride on the surface, and drying in an oven. The mass ratio of hexadecyltrimethylammonium bromide, carbon nanotubes and sodium alginate was 3:3:1, and the concentration of carbon nanotubes was 0.2 wt%.

[0050] d. The composite material obtained in step c is immersed in a mixture of hydrochloric acid, ferric chloride hexahydrate, and pyrrole monomer for 3 hours. Excess polypyrrole on the surface is washed away, and then the mixture is dried in an oven to obtain the composite material. The volume ratio of the hydrochloric acid and ferric chloride hexahydrate mixture to the pyrrole monomer is 0.5:1, and the concentration of hydrochloric acid is 1 mol·L⁻¹. -1 The concentration of ferric chloride hexahydrate is 0.1 mol·L⁻¹. -1 The concentration of pyrrole monomer is the same as the concentration of ferric chloride hexahydrate;

[0051] e. Cut a 100-mesh stainless steel mesh with the same area as the evaporation zone of the composite material prepared in step d. Connect and fix the stainless steel mesh to the composite material obtained in step d using conductive adhesive. This yields the electrothermal assisted solar interface evaporation composite material, which can be used in brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification.

[0052] Example 3

[0053] The apparatus in the solar interface evaporation system is based on Example 1;

[0054] a. Using a concentration of 3 mol·L -1 A sodium hydroxide solution was used to heat-treat a polyacrylonitrile fiber fabric at 60°C for 2 hours.

[0055] b. Place the polyacrylonitrile fiber fabric treated in step a into a solution with a concentration of 10 g·L⁻¹. -1 Dopamine hydrochloride and a concentration of 100 mmol·L -1 The mixture was placed in a solution of trimethylamine hydrochloride with a pH of 9, and then shaken in a shaker at 200 rpm and 40°C for 36 hours to ensure that polydopamine was evenly distributed on the fiber fabric. After the reaction was completed, excess polydopamine on the fiber fabric was washed off, and then the fabric was dried in an oven to obtain the composite material.

[0056] c. Immerse both sides of the composite material treated in step b in a sodium alginate-carbon nanotube dispersion containing cetyltrimethylammonium bromide as a surfactant and ultrasonically dispersed for 4 min. Then, ultrasonically disperse the nanotubes using an ultrasonic cell disruptor for 2 h at 250 W. Dry the nanotubes in an oven at 100℃ for 5 times to grow carbon nanotubes in situ on the fiber fabric. Finally, immerse the nanotubes in a 1 mol·L⁻¹ solution. -1 The composite material was obtained by soaking in anhydrous calcium chloride solution for 12 hours for crosslinking, washing off excess calcium chloride on the surface, and drying in an oven. The mass ratio of hexadecyltrimethylammonium bromide, carbon nanotubes and sodium alginate was 3:3:1, and the concentration of carbon nanotubes was 0.5wt%.

[0057] d. The composite material obtained in step c is immersed in a mixture of hydrochloric acid, ferric chloride hexahydrate, and pyrrole monomer for 3 hours. Excess polypyrrole on the surface is washed away, and then the mixture is dried in an oven to obtain the composite material. The volume ratio of the hydrochloric acid and ferric chloride hexahydrate mixture to the pyrrole monomer is 1.5:1, and the concentration of hydrochloric acid is 1 mol·L⁻¹. -1 The concentration of ferric chloride hexahydrate is 1 mol·L⁻¹ -1 The concentration of pyrrole monomer is the same as the concentration of ferric chloride hexahydrate;

[0058] e. Cut a 100-mesh stainless steel mesh with the same area as the evaporation zone of the composite material prepared in step d. Connect and fix the stainless steel mesh to the composite material obtained in step d using conductive adhesive. This yields the electrothermal assisted solar interface evaporation composite material, which can be used in brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification.

[0059] Example 4

[0060] The apparatus in the solar interface evaporation system is based on Example 1:

[0061] a. Using a concentration of 2 mol·L -1 A sodium hydroxide solution was used to heat-treat basalt fiber fabric at 80°C for 2 hours.

[0062] b. Place the fiber fabric treated in step a into a solution with a concentration of 5 g·L⁻¹. -1 Dopamine hydrochloride and a concentration of 80 mmol·L -1 The mixture was placed in a solution of trimethylamine hydrochloride with a pH of 9, and then shaken in a shaker at 150 rpm and 30°C for 28 hours to ensure that polydopamine was evenly distributed on the fiber fabric. After the reaction was completed, excess polydopamine on the fiber fabric was washed off, and then the fabric was dried in an oven to obtain the composite material.

[0063] c. Immerse both sides of the composite material treated in step b in a sodium alginate-carbon nanotube dispersion containing cetyltrimethylammonium bromide as a surfactant and ultrasonically dispersed for 2 minutes. Then, ultrasonically disperse the nanotubes using an ultrasonic cell disruptor for 1.5 hours at 250W. Dry the nanotubes in an oven at 90℃. Repeat this process three times to grow carbon nanotubes in situ on the fiber fabric. Finally, immerse the nanotubes in a 0.5 mol·L⁻¹ solution. -1 The composite material was obtained by soaking in anhydrous calcium chloride solution for 10 hours for crosslinking, washing off excess calcium chloride on the surface, and drying in an oven. The mass ratio of hexadecyltrimethylammonium bromide, carbon nanotubes and sodium alginate was 3:3:1, and the concentration of carbon nanotubes was 0.3wt%.

[0064] d. The composite material obtained in step c is immersed in a mixture of hydrochloric acid, ferric chloride hexahydrate, and pyrrole monomer for 3 hours. Excess polypyrrole on the surface is washed away, and then the mixture is dried in an oven to obtain the composite material. The volume ratio of the hydrochloric acid and ferric chloride hexahydrate mixture to the pyrrole monomer is 1.5:1, and the concentration of hydrochloric acid is 1 mol·L⁻¹. -1 The concentration of ferric chloride hexahydrate is 1 mol·L⁻¹ -1 The concentration of pyrrole monomer is the same as the concentration of ferric chloride hexahydrate;

[0065] e. Cut a 60-mesh stainless steel mesh with the same area as the evaporation zone of the composite material prepared in step d. Connect and fix the stainless steel mesh to the composite material obtained in step d using conductive adhesive. This yields the electrothermal assisted solar interface evaporation composite material, which can be used in brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification.

[0066] Example 5

[0067] The apparatus in the solar interface evaporation system is based on Example 1:

[0068] a. Using a concentration of 3 mol·L -1 A sodium hydroxide solution was used to heat-treat carbon fiber fabric at 110°C for 1 hour.

[0069] b. Place the fiber fabric and carbon fiber fabric treated in step a into a solution with a concentration of 10 g·L⁻¹. -1 Dopamine hydrochloride and a concentration of 50 mmol·L -1 The mixture was placed in a solution of trimethylamine hydrochloride with a pH of 9, and then shaken in a shaker at 200 rpm and 40°C for 48 hours to ensure that polydopamine was evenly distributed on the fiber fabric. After the reaction was completed, excess polydopamine on the fiber fabric was washed off, and then the fabric was dried in an oven to obtain the composite material.

[0070] c. Immerse both sides of the composite material treated in step b in a sodium alginate-carbon nanotube dispersion containing cetyltrimethylammonium bromide as a surfactant and ultrasonically dispersed for 3 minutes. Then, perform ultrasonic dispersion for 1 hour using an ultrasonic cell disruptor at 250W. Dry in an oven at 85℃. Repeat this process 5 times to grow carbon nanotubes in situ on the fiber fabric. Finally, place the mixture in a 1 mol·L⁻¹ solution. -1 The composite material was obtained by soaking in anhydrous calcium chloride solution for 12 hours for crosslinking, washing off excess calcium chloride on the surface, and drying in an oven. The mass ratio of hexadecyltrimethylammonium bromide, carbon nanotubes and sodium alginate was 3:3:1, and the concentration of carbon nanotubes was 0.3wt%.

[0071] d. The composite material obtained in step c is immersed in a mixture of hydrochloric acid, ferric chloride hexahydrate, and pyrrole monomer for 3 hours. Excess polypyrrole on the surface is washed away, and then the mixture is dried in an oven to obtain the composite material. The volume ratio of the hydrochloric acid and ferric chloride hexahydrate mixture to the pyrrole monomer is 2:1, and the concentration of hydrochloric acid is 1 mol·L⁻¹. -1 The concentration of ferric chloride hexahydrate is 1 mol·L⁻¹ -1 The concentration of pyrrole monomer is the same as the concentration of ferric chloride hexahydrate;

[0072] e. Cut an 80-mesh stainless steel mesh with the same area as the evaporation zone of the composite material prepared in step d. Connect and fix the stainless steel mesh to the composite material obtained in step d using conductive adhesive. This yields the electrothermal assisted solar interface evaporation composite material, which can be used in brackish water desalination, seawater desalination, steam power generation, thermal energy harvesting, and industrial saline wastewater purification.

[0073] Example 6

[0074] The apparatus in the solar interface evaporation system is based on Example 1:

[0075] a. Using a concentration of 1 mol·L -1 A sodium hydroxide solution was used to heat-treat a polyacrylonitrile fiber fabric at 100°C for 2 hours.

[0076] b. Place the polyacrylonitrile fiber fabric treated in step a into a solution with a concentration of 2 g·L⁻¹. -1 Dopamine hydrochloride and a concentration of 20 mmol·L -1 The mixture was placed in a solution of trimethylamine hydrochloride at pH 8, and then shaken in a shaker at 100 rpm and 30°C for 40 hours to ensure that polydopamine was evenly distributed on the fiber fabric. After the reaction was completed, excess polydopamine on the fiber fabric was washed off, and then the fabric was dried in an oven to obtain the composite material.

[0077] c. Immerse both sides of the composite material treated in step b in a sodium alginate-carbon nanotube dispersion containing cetyltrimethylammonium bromide as a surfactant and ultrasonically dispersed for 3 minutes. Then, ultrasonically disperse the nanotubes using an ultrasonic cell disruptor for 1 hour at 250W. Dry the nanotubes in an oven at 100℃, repeating this process twice. This allows for in-situ growth of carbon nanotubes on the fiber fabric. Finally, immerse the nanotubes in a 0.1 mol·L⁻¹ solution. -1 The composite material was obtained by soaking in anhydrous calcium chloride solution for 11 hours for crosslinking, washing off excess calcium chloride on the surface, and drying in an oven. The mass ratio of hexadecyltrimethylammonium bromide, carbon nanotubes and sodium alginate was 3:3:1, and the concentration of carbon nanotubes was 0.2 wt%.

[0078] d. The composite material obtained in step c is immersed in a mixture of hydrochloric acid, ferric chloride hexahydrate, and pyrrole monomer for 3 hours. Excess polypyrrole on the surface is washed away, and then the mixture is dried in an oven to obtain the composite material. The volume ratio of the hydrochloric acid and ferric chloride hexahydrate mixture to the pyrrole monomer is 0.5:1, and the concentration of hydrochloric acid is 1 mol·L⁻¹. -1 The concentration of ferric chloride hexahydrate is 0.5 mol·L⁻¹. -1 The concentration of pyrrole monomer is the same as the concentration of ferric chloride hexahydrate;

[0079] e. Cut a 100-mesh stainless steel mesh with the same area as the evaporation region of the composite material prepared in step d. Connect and fix the stainless steel mesh to the composite material obtained in step d using conductive adhesive. This yields the electrothermal assisted solar interface evaporation system. The evaporation rate is described in [reference needed]. Figure 5 Under one solar intensity and 1.5V voltage, and under one solar intensity and +1.5V voltage, the evaporation rates of brackish water are 1 kg·m³. -2 ·h -1 2.37 kg·m -2 ·h -1 3.22 kg·m -2 ·h -1 ;

[0080] Figure 6 Using simulated brackish water as a sample, this system was used for evaporative desalination. The Na+ content before and after desalination was measured using an Agilent 5900 plasma atomic emission spectrometer. + Mg 2+ K + and Ca 2+ The concentrations of the four ions in the treated water were significantly reduced, far exceeding the requirements of the WHO drinking water standards.

Claims

1. An electrothermal assisted solar interface evaporation system, characterized in that, The system consists of a solar interfacial evaporation composite material and a solar interfacial evaporation device, wherein the preparation of the composite material is carried out according to the following steps: a. Using a concentration of 1-3 mol·L -1 A sodium hydroxide solution is used to heat-treat basalt fiber fabrics, carbon fiber fabrics, or polyacrylonitrile fiber fabrics at a temperature of 60-120℃ for 1-5 hours. b. Place the fiber fabric treated in step a into a solution with a concentration of 1-10 g·L⁻¹ -1 Dopamine hydrochloride and concentrations of 1-100 mmol·L -1 The mixture was placed in a solution of trimethylamine hydrochloride with a pH of 8-9, and then shaken in a shaker at a speed of 100-200 rpm and a temperature of 20-40 ℃ for 24-48 h to ensure that polydopamine was evenly distributed on the fiber fabric. After the reaction was completed, excess polydopamine on the fiber fabric was washed off, and then the fabric was dried in an oven to obtain the composite material. c. Immerse both sides of the composite material treated in step b in a sodium alginate-carbon nanotube dispersion with cetyltrimethylammonium bromide as the surfactant and ultrasonically dispersed for 1-4 min, then dry in an oven at 80-100℃. Repeat 2-5 times to grow carbon nanotubes in situ on the fiber fabric. Then immerse the composite material in a 0.1-1 mol·L⁻¹ solution. -1 The composite material was obtained by soaking in anhydrous calcium chloride solution for 8-12 h for crosslinking, washing off excess calcium chloride on the surface, and drying in an oven. The mass ratio of hexadecyltrimethylammonium bromide, carbon nanotubes and sodium alginate was 3:3:1, the concentration of carbon nanotubes was 0.1-0.5 wt%, and ultrasonic dispersion was performed using an ultrasonic cell disruptor for 0.5-2 h at a power of 250 W. d. Immerse the composite material obtained in step c in a mixture of hydrochloric acid, ferric chloride hexahydrate, and pyrrole monomer for 3-5 hours. Wash away excess polypyrrole from the surface, and then dry it in an oven to obtain the composite material. The volume ratio of the hydrochloric acid and ferric chloride hexahydrate mixture to the pyrrole monomer is 0.5-2.5:1, and the concentration of hydrochloric acid is 1 mol·L⁻¹. -1 The concentration of ferric chloride hexahydrate is 0.1-1 mol·L⁻¹ -1 The concentration of pyrrole monomer is the same as the concentration of ferric chloride hexahydrate; e. Cut a stainless steel mesh with the same area as the evaporation region of the composite material prepared in step d, and connect and fix the stainless steel mesh to the composite material obtained in step d using conductive adhesive to obtain the electrothermal assisted solar interface evaporation composite material; The stainless steel mesh is 60-100 mesh. The composite material has an evaporation rate of 3.0-3.5 kg·m³ under one solar radiation intensity and a DC voltage of 1.5 V. -2 ·h -1 ; This system converts solar energy into electrical energy, which is then converted into heat energy through a stainless steel mesh, working in conjunction with the photothermal layer to achieve low-voltage, high-efficiency interfacial evaporation.

2. The solar interface evaporation device involved in the electrothermal assisted solar interface evaporation system as described in claim 1, characterized in that, The device consists of a solar power generation component and an evaporator; the solar power generation component is composed of a solar panel (1) and a solar cell (2), the solar panel (1) is connected to the solar cell (2), the solar panel (1) converts solar energy into electrical energy and stores the electrical energy in the solar cell (2); The evaporator is composed of a DC power supply (3), wires (4), a water tank (5), a photothermal layer (6), a heat insulation layer (7), and an electric heating layer (8); the solar cell (2) is connected to the DC power supply (3); the DC power supply (3) is connected to the electric heating layer (8) through the wires (4), and the DC power supply (3) controls the required output voltage and current of the electric heating layer (8); the water tank (5) is composed of two acrylic glass tanks connected by acrylic glass sheets; the glass sheets of the water tank (5) are provided with a photothermal layer (6) and an electric heating layer (8); a heat insulation layer (7) is provided directly above the water tank (5); The water storage tank (5) is made of plexiglass; the photothermal layer (6) and the electrothermal layer (8) are made of electrothermal assisted solar interface evaporation composite material; the heat insulation layer (7) is polystyrene foam; The solar panel (1) converts solar energy into electrical energy for storage. The current flows through the conductor (4) through the electrothermal layer (8) to generate heat, and the electrothermal layer (6) is simultaneously evaporated by the electric heating.

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