Porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion as well as preparation method and application of porous polyurethane skeleton interface evaporator

Abstract

The invention discloses a porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion and a preparation method and application thereof.The method comprises the steps that a Ti3AlC2 precursor is selectively etched through a lithium salt-acid system, and MXene powder is prepared; polyvinylpyrrolidone is dissolved in distilled water to form a dispersion medium, carbon black and MXene powder are added into the dispersion medium for uniform dispersion, and a composite photo-thermal dispersion system is constructed; then, polyurethane foam is immersed in the dispersion system, through adsorption and drying treatment, the photo-thermal material is stably loaded on the surface of a foam framework and in internal pore channels, and therefore the composite photo-thermal evaporator with the high light absorption capacity and the efficient water transportation performance is obtained. The preparation method is simple in technological process, wide in raw material source, low in cost and environmentally friendly, and the prepared photo-thermal evaporator is suitable for high-salinity wastewater treatment and has a good application prospect in the field of water-salt-energy synergistic utilization.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and relates to photothermal conversion materials, specifically to a porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion, its preparation method, and its application. Background Technology

[0002] With the acceleration of industrialization and the intensification of human activities, problems such as seawater desalination and high-salinity wastewater treatment are becoming increasingly prominent. Although traditional water treatment technologies such as distillation, reverse osmosis, and electrodialysis can effectively separate salts and impurities, they generally suffer from high energy consumption, complex equipment, serious pollution, and high operation and maintenance costs, making it difficult to meet the needs of sustainable development.

[0003] In recent years, solar interface evaporation technology has been considered an important approach to achieving low-energy, high-efficiency water purification due to its ability to directly utilize solar energy to drive evaporation. This technology typically relies on photothermal materials to convert light energy into heat energy, achieving efficient water vapor generation at the evaporation interface. However, when treating high-salinity or concentrated wastewater, salt tends to crystallize and accumulate on the evaporator surface, leading to decreased light absorption efficiency and hindered water transport, thereby significantly reducing the evaporation rate and system stability.

[0004] Current research has attempted to improve the salt resistance of evaporators through surface modification and hydrophilic / hydrophobic modulation. For example, Han et al. synthesized a one-dimensional Fe / C material using a hydrothermal method and loaded it onto a glass fiber membrane. They then combined this with PDMS modification to construct a Janus structure, creating an interface with hydrophobic / hydrophilic asymmetry, thereby inducing steam generation in localized areas. Furthermore, Li et al. employed a non-contact evaporator strategy, combining the efficient photothermal conversion of Ag-NSP absorbers with the rapid moisture transport capabilities of bamboo fiber paper shells to construct a core / shell structure 3D evaporator. However, these methods still suffer from problems such as complex fabrication processes, high material costs, poor adhesion of the photothermal layer, and insufficient long-term stability, especially in high-salinity environments where sustained and stable evaporation remains difficult to achieve.

[0005] Therefore, there is an urgent need to develop a photothermal evaporator that is simple to prepare, low in cost, has excellent light absorption performance, and good resistance to salt crystallization. Summary of the Invention

[0006] The purpose of this invention is to provide a porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion, its preparation method and application. By uniformly loading carbon black onto a porous polyurethane foam skeleton, a composite structure with both high light absorption and efficient water transport performance is constructed, thereby achieving efficient photothermal conversion while realizing the directional accumulation of salt. It is suitable for the efficient evaporation and resource utilization of high salinity wastewater.

[0007] This invention is achieved through the following technical solution: A method for preparing a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion includes the following steps: Step 1: Dissolve polyvinylpyrrolidone in distilled water, heat and stir until completely dissolved to obtain a polyvinylpyrrolidone solution with a mass fraction of 0.2-0.4 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.2-0.5% by mass of carbon black and 0.2-0.5% by mass of MXene powder obtained in Step 2 to the polyvinylpyrrolidone solution obtained in Step 1, and stir to obtain a uniform and stable composite photothermal dispersion. Step 4: Place the polyurethane foam in the dispersion obtained in Step 3 and soak it for 5-8 hours while stirring. Step 5: Take out the sample obtained in Step 4, coat its top with a composite photothermal dispersion of the same concentration as in Step 3, and then vacuum dry the sample to obtain a porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion.

[0008] The present invention also has the following technical features: Preferably, the heating and stirring in step one involves heating in an oil bath at 60–95 °C and using a magnetic stirrer at 600–800 r·min. -1 Stir continuously at a certain speed for 40–60 minutes.

[0009] Preferably, the stirring in step three is performed using a magnetic stirrer at 600–800 r·min. -1 Stir continuously at a certain speed for 10–30 minutes.

[0010] Preferably, in step four, the polyurethane foam in the dispersion obtained in step three is stirred with a magnetic stirrer at 600–800 r·min at 20–30 °C. -1 The stirring speed is maintained at a constant rate.

[0011] Preferably, the vacuum drying in step five is performed by drying in a vacuum drying oven at 60-80°C for 8-10 hours.

[0012] The present invention also protects a porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion prepared by the method described above, which has a light absorption rate of more than 95% in the 300-2500 nm wavelength range and maintains good porous structure and capillary water transport performance.

[0013] Furthermore, the prepared porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, when treating distilled water, exhibits performance at a light intensity of 1 kW / m². 2 Under these conditions, its evaporation rate reaches 3.58 kg / m³. 2 / h; When treating a 25wt% NaCl solution, under a light intensity of 1 kW / m 2 Under these conditions, its evaporation rate reaches 2.04 kg / m³. 2 / h.

[0014] This invention also protects the application of a porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion as described above in the treatment of high-salinity wastewater.

[0015] Compared with the prior art, the present invention has the following technical effects: This invention uses common polyurethane foam as a porous framework and polyvinylpyrrolidone as a dispersing stabilizer to enable MXene-carbon black particles to uniformly adhere to the surface of the porous structure, forming a composite structure with both high light absorption and efficient water transport properties: MXene (Ti3C2T x MXene possesses excellent metallic conductivity and broad-spectrum absorption characteristics, enabling it to efficiently capture near-infrared light; carbon black, on the other hand, excels in visible light absorption. The two form a complementary spectral absorption system, allowing the evaporator to achieve a light absorption rate of over 95% in the 300–2500 nm wavelength range, maximizing the utilization of solar energy. Simultaneously, MXene's high thermal conductivity can rapidly transfer the heat energy converted from light energy to the evaporation interface, preventing local overheating that could lead to material aging. Together with carbon black, it achieves a closed-loop photothermal conversion process of "efficient light absorption - rapid heat conduction - concentrated heat generation." The three-dimensional porous structure of polyurethane foam (high porosity and uniform pore size distribution) creates an efficient water transport channel. Combined with the hydrophilicity of the MXene / carbon black surface modified with polyvinylpyrrolidone, water is continuously transported to the evaporation interface through capillary action, ensuring the dynamic balance of "water-heat-vapor" during evaporation and avoiding a decrease in evaporation rate due to insufficient water supply. The porous structure and surface energy difference of the evaporator ensure that when high-salt solutions evaporate, salt crystallizes only at the outer edge. In the core evaporation zone, due to continuous water vapor generation, salt ions are difficult to retain. At the same time, the edge-crystallized salt naturally falls off under the dual action of gravity and water vapor flow, preventing salt from clogging the pores or covering the photothermal layer, thus solving the core problem of "salt blockage failure" in traditional evaporators. The porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion of the present invention exhibits excellent salt crystallization resistance and high-efficiency evaporation performance in high-salinity water bodies; in a 25wt% NaCl solution, the evaporation rate reaches 2.04 kg / m³. 2After running continuously for 3 days in a 20wt% NaCl solution, the evaporation rate remains above 1.7 kg / m² / h, and the salt crystallizes only at the outer edge of the evaporator, while the central evaporation area remains clean. The crystallized salt can fall off naturally, making it suitable for high-salt industrial wastewater treatment, seawater desalination, and other scenarios. It also has good application prospects in the field of water-salt-energy synergistic utilization. Attached Figure Description

[0016] Figure 1 Surface temperature rise curves of PU and the PU / PVP@CB / MXene evaporator prepared in Example 1 under one solar irradiation in pure water; Figure 2 A bar graph showing the stability test of the evaporation performance of the PU / PVP@CB / MXene interface evaporator prepared in Example 2; Figure 3 Thermogravimetric analysis diagrams of PU and the PU / PVP@CB / MXene interface evaporator prepared in Example 3; Figure 4 Stability test of evaporation performance of the PU / PVP@CB / MXene interface evaporator prepared in Example 4; Figure 5 Photograph of directional salt crystallization in brine of the PU / PVP@CB / MXene interfacial evaporator prepared in Example 5; Figure 6 The salt deposition rate diagram is shown in the salt deposition experiment of the PU / PVP@CB / MXene interface evaporator prepared in Example 6. Figure 7 The potential difference test diagram of the salt accumulation region at the center and side of the evaporation region during the salt accumulation process of the PU / PVP@CB / MXene interface evaporator prepared in Example 7. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0018] The polyurethane foam used in the following examples is low density (20 kg·m³). -3 Soft PU foam with high porosity (~95%), open-cell type, and three-dimensional interconnected porous structure.

[0019] The specific process for preparing MXene powder by selective etching of Ti3AlC2 powder in the following examples includes: dissolving 1.5 g of lithium fluoride in 40 mL of 9 M hydrochloric acid solution to form an etching system; adding 1 g of Ti3AlC2 powder to the etching system and stirring at 200 rpm for 24 h in a 35 ℃ water bath; after the reaction, centrifuging the resulting solution at 3500 rpm and washing it three times with deionized water until the pH of the supernatant is 5-6; then centrifuging the resulting dispersion at 3500 rpm for 1 h to obtain an MXene aqueous dispersion, and then... MXene powder was obtained by freeze-drying at 80 °C for 48 h.

[0020] Example 1: This embodiment presents a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, and its preparation method is as follows: Step 1: Dissolve 200 mg of polyvinylpyrrolidone in 100 ml of distilled water. Place the resulting mixture in an oil bath at 90 °C and heat it using a magnetic stirrer at 600 r·min. -1 The mixture was stirred continuously at a certain speed for 40 minutes until completely dissolved, resulting in a polyvinylpyrrolidone solution with a mass fraction of 0.2 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.3 g of carbon black and 0.5 g of MXene powder to 100 g of polyvinylpyrrolidone solution, and stir with a magnetic stirrer at 800 r·min. -1 Stir continuously at a certain speed for 30 minutes to obtain a uniform and stable dispersion; Step 4: Take a piece of polyurethane foam with dimensions of 2 cm × 2 cm × 3.5 cm, immerse it in the dispersion obtained in Step 3, and stir it at 30 ℃ using a magnetic stirrer at 800 r·min. -1 The mixture was stirred at a constant speed for 6 hours to allow the carbon black to be fully adsorbed onto the surface and pores of the sponge skeleton. Step 5: Take out the sample obtained in Step 4, coat its top with a dispersion of the same concentration as in Step 3, and then place the sample in a vacuum drying oven at 60 °C for 10 h to ensure that the sample is completely dry. The PU / PVP@CB / MXene photothermal interface evaporator can then be obtained.

[0021] Figure 1 Surface temperature rise curves of PU and the PU / PVP@CB / MXene evaporator prepared in Example 1 under one solar irradiation in pure water; The results show that before loading CB / MXene, the PU evaporation interface temperature was relatively low, reaching 25.2℃ after 30 minutes. After loading, the evaporator prepared using this method increased to 37.7℃ after 30 minutes, 12℃ higher than before loading. This indicates that adding CB / MXene increases the surface temperature of the foam, effectively concentrating heat at the internal evaporation interface and ensuring the critical thermodynamic conditions.

[0022] Example 2: This embodiment presents a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, and its preparation method is as follows: Step 1: Dissolve 200 mg of polyvinylpyrrolidone in 100 ml of distilled water. Place the resulting mixture in an oil bath at 95 °C and heat it using a magnetic stirrer at 700 r·min. -1 The mixture was stirred continuously at a certain speed for 50 minutes until completely dissolved, thus obtaining a polyvinylpyrrolidone solution with a mass fraction of 0.25 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.5 g of carbon black and 0.5 g of MXene powder to 100 g of polyvinylpyrrolidone solution, and stir with a magnetic stirrer at 600 r·min. -1 Stir continuously at a certain speed for 30 minutes to obtain a uniform and stable dispersion; Step 4: Take a piece of polyurethane foam with dimensions of 2 cm × 2 cm × 3.5 cm, immerse it in the dispersion obtained in Step 3, and stir with a magnetic stirrer at 700 r·min. -1 The mixture was stirred at a constant speed for 6 hours to allow the carbon black to be fully adsorbed onto the surface and pores of the sponge skeleton. Step 5: Take out the sample obtained in Step 4, coat its top with a dispersion of the same concentration as in Step 3, and then place the sample in a vacuum drying oven at 70 °C for 8 h to ensure that the sample is completely dry. The PU / PVP@CB / MXene photothermal interface evaporator can then be obtained.

[0023] Figure 2 The bar graph shows the stability test of the evaporation performance of the interfacial evaporator prepared in Example 2. Evaporation experiments were conducted every two hours using pure water under one solar radiation intensity, with the interfacial evaporator sample prepared in Example 2 repeated 10 times. The results show that the evaporation rate of the evaporator remained stable and above 3 kg m³ throughout the entire 10 cycles. 2 h 1 .

[0024] Example 3: This embodiment presents a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, and its preparation method is as follows: Step 1: Dissolve 300 mg of polyvinylpyrrolidone in 100 ml of distilled water. Place the resulting mixture in an oil bath at 80 °C and heat it using a magnetic stirrer at 800 r·min. -1 The mixture was stirred continuously at a certain speed for 50 minutes until completely dissolved, thus obtaining a polyvinylpyrrolidone solution with a mass fraction of 0.3 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.3 g of carbon black and 0.3 g of MXene powder to 100 g of polyvinylpyrrolidone solution, and stir with a magnetic stirrer at 700 r·min. -1 Stir continuously at a certain speed for 30 minutes to obtain a uniform and stable dispersion; Step 4: Take a piece of polyurethane foam with dimensions of 2 cm × 2 cm × 3.5 cm, immerse it in the dispersion obtained in Step 3, and stir with a magnetic stirrer at 800 r·min. -1 The mixture was stirred at a constant speed for 7 hours to allow the carbon black to be fully adsorbed onto the surface and pores of the sponge skeleton. Step 5: Take out the sample obtained in Step 4, coat its top with a dispersion of the same concentration as in Step 3, and then place the sample in a vacuum drying oven at 60 °C for 10 h to ensure that the sample is completely dry. The PU / PVP@CB / MXene photothermal interface evaporator can then be obtained.

[0025] Figure 3 Thermogravimetric analysis (TGA) diagrams of PU and the PU / PVP@CB / MXene interfacial evaporator prepared in Example 3 are shown. The analysis results indicate that the thermal decomposition mass loss of PU is 78%, while the external decomposition mass loss of PU / PVP@CB / MXene is 68%, and the internal decomposition mass loss is 36%. By comparing the differences in internal and external decomposition behavior, it can be inferred that the hot-air drying process of the evaporator allows PVP@CB / MXene to form a more stable structure within the PU framework, effectively suppressing the thermal decomposition process. Its thermal stability is superior to that of the external region, confirming the difference in the internal and external distribution of PU / PVP@CB / MXene.

[0026] Example 4: This embodiment presents a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, and its preparation method is as follows: Step 1: Dissolve 400 mg of polyvinylpyrrolidone in 100 ml of distilled water. Place the resulting mixture in an oil bath at 80 °C and heat it using a magnetic stirrer at 600 r·min. -1 The mixture was stirred continuously at a certain speed for 50 minutes until completely dissolved, resulting in a polyvinylpyrrolidone solution with a mass fraction of 0.4 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.5 g of carbon black and 0.5 g of MXene powder to 100 g of polyvinylpyrrolidone solution, and stir with a magnetic stirrer at 800 r·min. -1 Stir continuously at a certain speed for 10 minutes to obtain a uniform and stable dispersion; Step 4: Take a piece of polyurethane foam with dimensions of 2 cm × 2 cm × 3.5 cm, immerse it in the dispersion obtained in Step 3, and stir with a magnetic stirrer at 800 r·min. -1 Stirring at a constant speed for 5 hours allows the carbon black to be fully adsorbed onto the surface and pores of the sponge skeleton. Step 5: Take out the sample obtained in Step 4, coat its top with a dispersion of the same concentration as in Step 3, and then place the sample in a vacuum drying oven at 80 ℃ for 8 h to ensure that the sample is completely dry. The PU / PVP@CB / MXene photothermal interface evaporator can then be obtained.

[0027] Figure 4 The evaporation performance stability of the PU / PVP@CB / MXene interface evaporator prepared in Example 4 was tested. Evaporation experiments were conducted using 20 wt% brine under 1 solar intensity. The evaporation rate was monitored in real time during the experiment, and the rates on days 1, 2, 5, and 10 were recorded. The results showed that the evaporation rate decreased only slightly, remaining at 1.7 kg m³ after the third day. 2 h 1 above.

[0028] Example 5: This embodiment presents a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, and its preparation method is as follows: Step 1: Dissolve 200 mg of polyvinylpyrrolidone in 100 ml of distilled water. Place the resulting mixture in an oil bath at 70 °C and heat it using a magnetic stirrer at 800 r·min. -1 The mixture was stirred continuously at a certain speed for 60 minutes until completely dissolved, resulting in a polyvinylpyrrolidone solution with a mass fraction of 0.2 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.4 g of carbon black and 0.4 g of MXene powder to 100 g of polyvinylpyrrolidone solution, and stir with a magnetic stirrer at 700 r·min. -1 Stir continuously at a certain speed for 20 minutes to obtain a uniform and stable dispersion; Step 4: Take a piece of polyurethane foam with dimensions of 2 cm × 2 cm × 3.5 cm, immerse it in the dispersion obtained in Step 3, and stir with a magnetic stirrer at 700 r·min. -1 The mixture was stirred at a constant speed for 8 hours to ensure that the carbon black was fully adsorbed onto the surface and pores of the sponge skeleton. Step 5: Take out the sample obtained in Step 4, coat its top with a dispersion of the same concentration as in Step 3, and then place the sample in a vacuum drying oven at 60 °C for 10 h to ensure that the sample is completely dry. The PU / PVP@CB / MXene photothermal interface evaporator can then be obtained.

[0029] Figure 5 This image shows the directional salt crystallization of the PU / PVP@CB / MXene interfacial evaporator prepared in Example 5 in brine. A high-salinity 20 wt% NaCl solution was used as a representative brine sample to visually demonstrate the salt secretion characteristics and localized salt crystallization ability of the photothermal evaporator. After 3 days of continuous operation, salt crystallization was observed only at the edges near the outer region on the evaporator surface, while the central region, where water evaporated rapidly, remained clean. As steam generation and salt secretion continued, the accumulation of salt crystals gradually increased, eventually detaching under gravity, completing salt collection. Throughout the experiment, no salt crystals formed at the evaporation interface, ensuring continuous and effective water vapor generation.

[0030] Example 6: This embodiment presents a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, and its preparation method is as follows: Step 1: Dissolve 300 mg of polyvinylpyrrolidone in 100 ml of distilled water. Place the resulting mixture in an oil bath at 60 °C and heat it using a magnetic stirrer at 600 r·min. -1 The mixture was stirred continuously at a certain speed for 50 minutes until completely dissolved, thus obtaining a polyvinylpyrrolidone solution with a mass fraction of 0.2 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.3 g of carbon black and 0.3 g of MXene powder to 100 g of polyvinylpyrrolidone solution, and stir with a magnetic stirrer at 800 r·min. -1 Stir continuously at a certain speed for 10 minutes to obtain a uniform and stable dispersion; Step 4: Take a piece of polyurethane foam with dimensions of 2 cm × 2 cm × 3.5 cm, immerse it in the dispersion obtained in Step 3, and stir with a magnetic stirrer at 800 r·min. -1 The mixture was stirred at a constant speed for 8 hours to ensure that the carbon black was fully adsorbed onto the surface and pores of the sponge skeleton. Step 5: Take out the sample obtained in Step 4, coat its top with a dispersion of the same concentration as in Step 3, and then place the sample in a vacuum drying oven at 70 °C for 9 h to ensure that the sample is completely dry. The PU / PVP@CB / MXene photothermal interface evaporator can then be obtained.

[0031] Figure 6 The salt deposition rate diagram is shown in Example 6 for the salt deposition experiment of the PU / PVP@CB / MXene interface evaporator; as shown. Figure 6 The sample used was a high-salinity 20 wt% NaCl solution. This evaporator exhibited a good salt accumulation rate in the salt accumulation experiment, with rates of 136.45 gm³ on days 1, 2, and 3. -2 h -1 119.87 gm -2 h -1 97.11 gm -2 h -1 All of them have good salt deposition effect, which significantly exceeds the existing technology, demonstrating the superiority and leading position of this technology in the field of solar desalination.

[0032] Example 7: This embodiment presents a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, and its preparation method is as follows: Step 1: Dissolve 400 mg of polyvinylpyrrolidone in 100 ml of distilled water. Place the resulting mixture in an oil bath at 60 °C and heat it using a magnetic stirrer at 600 r·min. -1 The mixture was stirred continuously at a certain speed for 60 minutes until completely dissolved, resulting in a polyvinylpyrrolidone solution with a mass fraction of 0.4 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.2 g carbon black and 0.2 g MXene powder to 100 g polyvinylpyrrolidone solution, and stir with a magnetic stirrer at 800 r·min. -1 Stir continuously at a certain speed for 10 minutes to obtain a uniform and stable dispersion; Step 4: Take a piece of polyurethane foam with dimensions of 2 cm × 2 cm × 3.5 cm, immerse it in the dispersion obtained in Step 3, and stir with a magnetic stirrer at 700 r·min. -1The mixture was stirred at a constant speed for 8 hours to ensure that the carbon black was fully adsorbed onto the surface and pores of the sponge skeleton. Step 5: Take out the sample obtained in Step 4, coat its top with a dispersion of the same concentration as in Step 3, and then place the sample in a vacuum drying oven at 70 °C for 8 h to ensure that the sample is completely dry. The PU / PVP@CB / MXene photothermal interface evaporator can then be obtained.

[0033] In recent years, directional salt-accumulating solar interface evaporators have provided a new way to convert solar energy into electricity. They generate electricity by utilizing the salt gradient between the evaporation zone and the salt accumulation zone of the evaporator, and can collect salt at the same time as generating electricity. Figure 7 The potential difference test diagram of the salt accumulation region at the center and side of the evaporation region during the salt accumulation process of the PU / PVP@CB / MXene interface evaporator prepared in Example 7 is shown below. Figure 7 The potential difference between the center and the side salt accumulation area of ​​the evaporation zone in the evaporator was measured using a multimeter. It was found that the potential difference after 1 h and 10 h of salt accumulation in 20 wt% NaCl solution was 0.340 V and 0.283 V, respectively. As the evaporation experiment proceeded, there was indeed a certain potential difference between the center and the side salt accumulation area of ​​the evaporator, and it remained at around 0.3 V after 10 h of salt accumulation.

[0034] The evaporator of this invention not only enables continuous seawater desalination but also simultaneously collects salt and generates electricity, demonstrating its potential applications in power generation. This technology promises to provide a sustainable energy solution for remote areas or islands lacking a stable power supply.

Claims

1. A method for preparing a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, characterized in that, Includes the following steps: Step 1: Dissolve polyvinylpyrrolidone in distilled water, heat and stir until completely dissolved to obtain a polyvinylpyrrolidone solution with a mass fraction of 0.2-0.4 wt%. Step 2: Prepare MXene powder by selective etching of Ti3AlC2 powder; Step 3: Add 0.2-0.5% by mass of carbon black and 0.2-0.5% by mass of MXene powder obtained in Step 2 to the polyvinylpyrrolidone solution obtained in Step 1, and stir to obtain a uniform and stable composite photothermal dispersion. Step 4: Place the polyurethane foam in the dispersion obtained in Step 3 and soak it for 5-8 hours while stirring. Step 5: Take out the sample obtained in Step 4, coat its top with a composite photothermal dispersion of the same concentration as in Step 3, and then vacuum dry the sample to obtain a porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion.

2. The method for preparing a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion according to claim 1, characterized in that, The heating and stirring described in step one involves heating in an oil bath at 60–95 °C and using a magnetic stirrer at 600–800 r·min. -1 Stir continuously at a certain speed for 40–60 minutes.

3. The method for preparing a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion according to claim 1, characterized in that, The stirring described in step three is performed using a magnetic stirrer at 600–800 r·min. -1 Continue stirring at a certain speed for 10–30 minutes.

4. The method for preparing a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion according to claim 1, characterized in that, In step four, the polyurethane foam is stirred in the dispersion obtained in step three at 20–30°C using a magnetic stirrer at 600–800 r·min. -1 The stirring speed is maintained at a constant rate.

5. The method for preparing a porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion according to claim 1, characterized in that, The vacuum drying described in step five involves drying in a vacuum drying oven at 60-80℃ for 8-10 hours.

6. A porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion, prepared by the method according to any one of claims 1 to 5, characterized in that, The light absorption rate is greater than 95% in the 300–2500 nm wavelength range, while maintaining good porous structure and capillary water transport performance.

7. The porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion according to claim 6, characterized in that, When treating distilled water, under a light intensity of 1 kW / m² 2 Under these conditions, its evaporation rate reaches 3.58 kg / m³. 2 / h.

8. The porous polyurethane framework interface evaporator based on MXene / carbon black synergistic photothermal conversion according to claim 6, characterized in that, The evaporator, when processing a 25wt% NaCl solution, operates under a light intensity of 1 kW / m². 2 Under these conditions, its evaporation rate reaches 2.04 kg / m³. 2 / h.

9. The application of a porous polyurethane skeleton interface evaporator based on MXene / carbon black synergistic photothermal conversion according to any one of claims 6 to 8 in the treatment of high salinity wastewater.

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