An ion regulation-based high-concentration brine treatment and power generation evaporation material and a preparation method thereof

Abstract

This invention discloses an integrated evaporation material and its preparation method for high-concentration brine treatment and power generation based on ion regulation, as well as a water treatment and energy harvesting system, belonging to the technical fields of solar interface evaporation. The material uses polyurethane sponge as a porous framework, constructs a photothermal and conductive network by impregnating conductive graphite with a sodium alginate suspension, and then crosslinks it twice with sodium alginate and calcium chloride, with polystyrene sulfonic acid impregnation introduced in between to form an ion-regulated gel layer containing sulfonate groups, constituting a three-layer composite structure. The material has a simple preparation process and low cost, and under one day of sunlight, the evaporation rate in a 20wt% sodium chloride solution is ≥3.6 kg·m³. ‑2 ·h ‑1 Furthermore, it is salt-free and can generate an open-circuit voltage of ≥800 mV and a short-circuit current of ≥600μA. It has a salt ion rejection rate of >99.9%, enabling efficient desalination and stable power generation of high-concentration brine, making it suitable for large-scale production applications.

Description

Technical Field

[0001] This invention relates to an apparatus for treating high-concentration brine and producing clean energy, specifically to an evaporation material and preparation method for treating and generating high-concentration brine based on ion regulation, belonging to the technical fields of solar interface evaporation, seawater desalination, wastewater treatment and environmental energy harvesting. Background Technology

[0002] With the escalating global water and energy crisis, the development of sustainable technologies capable of simultaneously producing freshwater and electricity is of great significance. Solar interfacial evaporation technology has attracted considerable attention due to its direct utilization of sunlight to produce freshwater. In recent years, researchers have further explored the recovery and conversion of the heat energy and concentration gradient energy (i.e., osmotic energy) generated during the evaporation process to achieve multi-stage energy utilization and construct a "hydropower cogeneration" system.

[0003] Existing related technologies mainly focus on the following areas: High-efficiency photothermal evaporation materials: Evaporation efficiency is improved by developing materials with broad-spectrum absorption (such as carbon-based materials, plasma metals, etc.).

[0004] Salt-resistant structural design: For example, designing asymmetric wetting structures and constructing directional water / salt transport channels to alleviate the problem of salt crystallization at the evaporation interface.

[0005] Integrated permeation energy harvesting: Introducing ion-selective membranes or functional materials into the evaporation device, and using the water-salt concentration difference generated by evaporation to generate electricity, thereby realizing the recovery of permeation energy.

[0006] The closest prior art to this invention is an asymmetric wetting structure evaporative material that integrates solar evaporation and infiltration power generation. This technology typically employs an asymmetric wetting structure or functionalized coating. While evaporating water, it utilizes the salt concentration difference between the photothermal interface and the bulk water to drive ions to migrate through selective channels, thereby generating electricity. For example, some studies have grafted negatively charged functional groups onto the evaporative material substrate, achieving selective cation transport through electrostatic repulsion, thus generating voltage.

[0007] These existing technologies provide important references for this invention, especially the basic idea of ​​coupling photothermal evaporation with permeation energy conversion, and the physicochemical mechanism of achieving charge separation using ion-selective materials.

[0008] Despite the progress made in existing research, the closest existing technology still has the following significant shortcomings: Insufficient salt resistance: Under high concentrations of salt water (e.g., >10 wt% NaCl) or long-term operating conditions, the salt resistance mechanism of existing evaporation materials is prone to failure. Salt will still crystallize at the evaporation interface or internal channels, leading to obstructed water transport, decreased photothermal performance, or even structural damage.

[0009] Poor energy conversion efficiency and stability: The electrical output (voltage, current) of existing integrated devices is typically low and unstable, especially after high salinity or long-term operation, resulting in severe degradation of power generation performance. The thermodynamic and kinetic matching mechanisms in multi-energy coupling processes are unclear.

[0010] High system complexity and cost: To achieve salt resistance and power generation, complex micro-nano structure fabrication, expensive ion-selective membranes, or fine surface modification processes are often required, which is not conducive to large-scale, low-cost preparation and application. Summary of the Invention

[0011] Technical issues Existing solar-hydropower cogeneration devices suffer from poor salt resistance, unstable power generation performance, and complex and costly manufacturing processes in high-salinity environments. Therefore, there is a need for an integrated cogeneration evaporation material that is simple to manufacture, low in cost, exhibits excellent long-term stability under extremely high salinity conditions, and can simultaneously achieve efficient freshwater production and stable high-power electrical output.

[0012] Technical content To address the aforementioned technical problems, the present invention provides the following solution: Using readily available and inexpensive polyurethane foam as a porous framework and support, a photothermal conversion layer and a conductive network are constructed by impregnating and loading conductive graphite. Then, by sequentially crosslinking sodium alginate and polystyrene sulfonic acid, an ion-regulated hydrogel layer rich in sulfonate groups is formed on the surface of the framework and within its pores. This composite structure achieves an organic unity of light absorption, water transport, ion selective sieving, and charge collection.

[0013] Compared with existing technologies, the advantages of this invention are: through a unique three-layer composite structure of "skeleton-conductive network-ion-regulated gel", especially the introduction of a hydrogel layer cross-linked with sulfonic acid groups, not only is efficient water transport ensured through its superhydrophilicity, but more importantly, the fixed negative charge (-SO3) it dissociates... - A strong ion-sieving electric field is formed inside the evaporation material. This electric field can actively repel anions, preventing salt crystallization at the source; on the other hand, it can selectively enrich and drive the directional migration of cations, greatly enhancing the conversion efficiency and stability of the concentration gradient energy into electrical energy caused by evaporation.

[0014] This invention provides an integrated evaporation material for high-concentration brine desalination and power generation. The integrated evaporation material comprises a porous framework layer, a photothermal and conductive layer, and an ion regulation layer.

[0015] Furthermore, the porous skeleton layer is composed of polyurethane foam.

[0016] Furthermore, the height of the polyurethane foam is 0.5~2 cm, and its length and width are not limited.

[0017] Preferably, the height of the polyurethane foam is 0.75~1.25 cm, and the length and width are not limited.

[0018] Specifically, the polyurethane foam may have the following specifications: length 1-3 cm, width 1-3 cm, and height 0.75-1.25 cm.

[0019] Furthermore, the photothermal and conductive layer is conductive graphite loaded on the porous framework layer.

[0020] Furthermore, the ion regulation layer is a hydrophilic gel layer covering the outside of the photothermal and conductive layer, and the hydrophilic gel layer is formed by cross-linking sodium alginate with calcium chloride and polystyrene sulfonic acid.

[0021] Furthermore, the integrated evaporation material may also have a packaging layer attached to the outside of the ion control layer; the packaging layer is made of plastic or glass.

[0022] Furthermore, the integrated evaporation material is suitable for use under 1 solar irradiance (1 kW·m²). -2 Under these conditions, in a 20 wt% sodium chloride solution, the evaporation rate is not less than 3.6 kg·m⁻². -2 ·h -1 Furthermore, there is no salt crystal accumulation on the surface.

[0023] Furthermore, the integrated evaporation material, in a 20 wt% sodium chloride solution, can generate an open-circuit voltage of not less than 800 mV and a short-circuit current of not less than 600 μA during the evaporation process.

[0024] The present invention also provides a method for preparing the above-mentioned integrated evaporation material, comprising the following steps: S1: Clean and dry the polyurethane foam; S2: The dried polyurethane sponge is impregnated in a suspension containing conductive graphite and sodium alginate, and then dried to obtain an intermediate with a conductive graphite network. S3: The intermediate is sequentially immersed in sodium alginate solution and calcium chloride solution to perform the first crosslinking; S4: The intermediate after the first crosslinking is immersed in a polystyrene sulfonic acid solution, dried, and then immersed in sodium alginate solution and calcium chloride solution in sequence for the second crosslinking. After drying, the integrated evaporation material is obtained.

[0025] Furthermore, the height of the polyurethane sponge in step S1 is 0.75~1.25 cm; the pore size of the sponge is 0.5-0.6 mm, and the number of pores is 30~50 ppi.

[0026] Furthermore, the cleaning described in step S1 includes cleaning with ethanol and / or deionized water; ultrasonic oscillation may be used during the cleaning process.

[0027] Furthermore, the concentration of conductive graphite in the suspension in step S2 is 50-250 mg / mL.

[0028] Preferably, the concentration of conductive graphite in the suspension in step S2 is 75~125 mg / mL.

[0029] Furthermore, the mass fraction of sodium alginate in the suspension in step S2 is 0.5-5 wt%.

[0030] Preferably, the mass fraction of sodium alginate in the suspension in step S2 is 0.5-2 wt%.

[0031] Furthermore, the immersion time in step S2 is 5 to 60 minutes.

[0032] Furthermore, the sodium alginate solution in steps S3 and S4 has a mass fraction of 0.5 to 3 wt%.

[0033] Furthermore, the mass fraction of calcium chloride in the calcium chloride solution described in steps S3 and S4 is 2-5 wt%.

[0034] Furthermore, the immersion time in sodium alginate solution in steps S3 and S4 is 5 to 20 minutes.

[0035] Furthermore, the immersion time in calcium chloride solution in steps S3 and S4 is 10-15 hours.

[0036] Furthermore, the concentration of polystyrene sulfonic acid in the polystyrene sulfonic acid solution in step S4 is 10-40 mg / mL.

[0037] Preferably, the concentration of polystyrene sulfonic acid in the polystyrene sulfonic acid solution in step S4 is 15-25 mg / mL.

[0038] Furthermore, the immersion time in the polystyrene sulfonic acid solution in step S4 is 15-60 minutes.

[0039] Furthermore, the drying temperature in steps S1 to S4 is 50-110°C, and the time is 0.5-5 hours.

[0040] Finally, the present invention provides an integrated evaporation material, and electrodes and a power management circuit electrically connected thereto, for collecting the electrical energy generated during the evaporation process.

[0041] Furthermore, the system includes multiple integrated evaporation material units, which are electrically connected in series or parallel to increase the output voltage or current.

[0042] Beneficial effects Through the above technical solution, the present invention achieves the following significant advantages over the prior art: Exceptional salt resistance and self-cleaning ability: After 10 days of continuous operation in a 20 wt% high-concentration sodium chloride brine, no visible salt crystals were observed at the evaporation interface. Even when salt was artificially sprinkled on the surface, the salt particles dissolved and flowed back within 2 hours, demonstrating its extremely strong resistance to salt crystallization and self-cleaning function.

[0043] Evaporation performance increases rather than decreases under high salinity: at 1 kW·m -2 Under light intensity, the evaporation rate in 20 wt% high-concentration brine is as high as 3.5-4.1 kg·m⁻². -2 ·h -1 This is significantly higher than its evaporation rate in pure water (3.2 kg·m³). -2 ·h -1 This breaks the traditional understanding that high salinity inhibits evaporation.

[0044] Stable and efficient power output: In 20wt% NaCl brine, this evaporation material can generate an open-circuit voltage of up to 820 mV and a short-circuit current of 646 μA, with stable output. Its power generation performance can be amplified by simple series and parallel connections; for example, 36 units in series can obtain a high voltage of 23.1 V, which can directly drive small electronic devices.

[0045] Excellent desalination performance: After desalinating simulated seawater, the main ions (Na+, Sodium ... + K + Ca 2+ Mg 2+ The retention rates of all samples were >99.9%, and the concentrations were far below the World Health Organization (WHO) drinking water standards.

[0046] Low cost and high scalability: All raw materials are inexpensive, and the preparation process is completed at room temperature and pressure through simple impregnation-crosslinking steps. No complex equipment is required, making it green and environmentally friendly, and very suitable for large-scale production. Attached Figure Description

[0047] Figure 1The results are for evaporation performance testing, where (a) is the test result of Example 1; (b) is the test result of Example 2; and (c) is the test result of Example 3.

[0048] Figure 2 The image shows the physical diagram of the GPU@HPS evaporation material in Example 4, where (a) is PU; (b) is GPU; (c) is GPU@H; and (d) is GPU@HPS.

[0049] Figure 3 This is a SEM image of the GPU@HPS evaporation material in Example 4.

[0050] Figure 4 The image shows the XRD pattern of the GPU@HPS evaporation material in Example 4.

[0051] Figure 5 The image shows the FT-IR image of the GPU@HPS evaporation material in Example 4.

[0052] Figure 6 The image shows the UV-vis spectrum of the GPU@HPS evaporation material in Example 4.

[0053] Figure 7 This is a test of the evaporation performance of the GPU@HPS evaporation material in Example 4.

[0054] Figure 8 This is a test of the power generation performance of the GPU@HPS evaporation material in Example 4. Detailed Implementation Plan Terminology Explanation GPU@HPS: This is the code name for the integrated evaporation material finally prepared in this invention. Wherein, G represents conductive graphite, P represents polystyrene sulfonic acid, U represents polyurethane sponge, H represents hydrogel, and S represents sulfonic acid groups.

[0055] One solar illumination: refers to a simulated solar light power density of 1 kilowatt per square meter (1 kW·m²). -2 (This refers to the standard test conditions.)

[0056] Intermediate water: refers to water molecules that are bound by the hydrophilic functional groups of the material, whose hydrogen bond network is altered, and which have a lower enthalpy of vaporization than free water.

[0057] Source of raw materials The commercial polyurethane (PU) sponge was purchased from Dongguan Chuangjie Sponge Products Co., Ltd., with a pore size of 0.5-0.6 mm and a pore count of 40 ppi.

[0058] Example 1 1. Clean a piece of commercial polyurethane (PU) sponge with dimensions of 2 cm × 2 cm × 1 cm by ultrasonic cleaning with anhydrous ethanol and deionized water, and then dry it in an oven at 60-110℃.

[0059] 2. Preparation of suspension: Conductive graphite powder was dispersed in deionized water to obtain different concentrations (0 mg / mL). -1 25 mg / mL -1 50 mg mL -1 100 mg mL -1 150 mg mL -1 200 mg mL -1 250 mg mL -1 A conductive graphite suspension was prepared, and then sodium alginate (1 wt% relative to the mass of the conductive graphite powder) was added as a binder and stirred evenly.

[0060] 3. Immerse the dried PU sponge completely in the above suspension to ensure full saturation. After removal, place it in a vacuum oven at 60-110℃ to dry, and obtain the GPU sample.

[0061] 4. Immerse the GPU sample obtained in step 3 in a 1 wt% sodium alginate aqueous solution for 10 minutes, then immediately immerse it in a 3 wt% calcium chloride aqueous solution for 12 hours for crosslinking. Afterwards, remove the GPU sample, wash it with deionized water, and dry it at 60°C to obtain the GPU@H sample.

[0062] 5. Immerse the GPU@H sample in a 20 mg / mL polystyrene sulfonic acid aqueous solution for 30 minutes, then remove and dry at 80℃ for 30 minutes.

[0063] 6. Repeat the crosslinking process in step 4: immerse the sample again in a 1 wt% sodium alginate solution for 10 minutes, then immerse it in a 3 wt% calcium chloride solution for 12 hours for crosslinking. Afterwards, remove the GPU@H sample, wash it with deionized water, and dry it at 60°C for 3 hours to obtain the target product, GPU@HPS evaporation material, of which 7 types are obtained.

[0064] Example 2 1. Clean a piece of commercial polyurethane (PU) sponge with dimensions of 2 cm × 2 cm × 1 cm by ultrasonic cleaning with anhydrous ethanol and deionized water, and then dry it in an oven at 60-110℃.

[0065] 2. Preparation of suspension: Conductive graphite powder was dispersed in deionized water to obtain a concentration of 100 mg / mL. -1 A conductive graphite suspension was prepared, and then sodium alginate (1 wt% relative to the mass of the conductive graphite powder) was added as a binder and stirred until homogeneous.

[0066] 3. Immerse the dried PU sponge completely in the above suspension to ensure full saturation. After removal, place it in a vacuum oven at 60-110℃ to dry, and obtain the GPU sample.

[0067] 4. Immerse the GPU sample obtained in step 3 in a 1 wt% sodium alginate aqueous solution for 10 minutes, then immediately immerse it in a 3 wt% calcium chloride aqueous solution for 12 hours for crosslinking. Afterwards, remove the GPU sample, wash it with deionized water, and dry it at 60°C to obtain the GPU@H sample.

[0068] 5. Immerse GPU@H samples in different concentrations (10 mg / mL). -1 20 mg mL -1 30 mg mL -1 and 40 mg mL -1 Soak the polystyrene in an aqueous solution of polystyrene sulfonic acid for 30 minutes, then remove and dry at 80°C for 30 minutes.

[0069] 6. Repeat the crosslinking process in step 4: immerse the sample again in a 1 wt% sodium alginate solution for 10 minutes, then immerse it in a 3 wt% calcium chloride solution for 12 hours for crosslinking. Afterwards, remove the GPU@H sample, wash it with deionized water, and dry it at 60°C for 3 hours to obtain the target product, GPU@HPS evaporation material, of which 4 types are obtained.

[0070] Example 3 1. Commercial polyurethane (PU) sponges of different sizes (2 cm × 2 cm × 0.5 cm, 2 cm × 2 cm × 1 cm, 2 cm × 2 cm × 1.5 cm, 2 cm × 2 cm × 2 cm) were ultrasonically cleaned with anhydrous ethanol and deionized water, and then dried in an oven at 60-110℃.

[0071] 2. Preparation of suspension: Conductive graphite powder was dispersed in deionized water to obtain a concentration of 100 mg / mL. -1 A conductive graphite suspension was prepared, and then sodium alginate (1 wt% relative to the mass of the conductive graphite powder) was added as a binder and stirred until homogeneous.

[0072] 3. Immerse the dried PU sponge completely in the above suspension to ensure full saturation. After removal, place it in a vacuum oven at 60-110℃ to dry, and obtain the GPU sample.

[0073] 4. Immerse the GPU sample obtained in step 3 in a 1 wt% sodium alginate aqueous solution for 10 minutes, then immediately immerse it in a 3 wt% calcium chloride aqueous solution for 12 hours for crosslinking. Afterwards, remove the GPU sample, wash it with deionized water, and dry it at 60°C to obtain the GPU@H sample.

[0074] 5. Immerse the GPU@H sample in an immersion solution with a concentration of 20 mg / mL. -1 Soak the polystyrene in an aqueous solution of sulfonic acid for 30 minutes, then remove and dry at 80°C for 30 minutes.

[0075] 6. Repeat the crosslinking process in step 4: immerse the sample again in a 1 wt% sodium alginate solution for 10 minutes, then immerse it in a 3 wt% calcium chloride solution for 12 hours for crosslinking. Afterwards, remove the GPU@H sample, wash it with deionized water, and dry it at 60°C for 3 hours to obtain the target product, GPU@HPS evaporation material, of which 5 types are obtained.

[0076] The evaporation performance of various GPU@HPS evaporation materials prepared in Examples 1-3 above was tested. The evaporation performance was measured using AM 1.5G standard solar simulation material (1 kW·m²). -2 Under these conditions, the GPU@HPS evaporation material was placed in a floating device, with pure water supplied from below via absorbent cotton. The evaporation efficiency was tested. Simultaneously, a portion of the GPU@HPS evaporation material (2 cm × 2 cm × 0.5 cm) was used as a control, submerged in the floating device with only the top surface exposed, recorded as 0 cm. The results are as follows: Figure 2 As shown. It can be observed that when the amount of conductive graphite added to the GPU@HPS evaporation material is 100 mg / mL... -1 The amount of polystyrene sulfonic acid added is 20 mg / mL. -1 The evaporation rate reaches its optimal value of 3.27 kg / m³ when the height is 1 cm. -2 h -1 It is 5.5 times that of pure water.

[0077] Example 4 1. Clean a piece of commercial polyurethane (PU) sponge with dimensions of 2 cm × 2 cm × 1 cm by ultrasonic cleaning with anhydrous ethanol and deionized water, and then dry it in an oven at 60-110℃.

[0078] 2. Preparation of suspension: Conductive graphite powder was dispersed in deionized water to obtain a concentration of 100 mg / mL. -1 A conductive graphite suspension was prepared, and then sodium alginate (1 wt% relative to the mass of the conductive graphite powder) was added as a binder and stirred until homogeneous.

[0079] 3. Immerse the dried PU sponge completely in the above suspension to ensure full saturation. After removal, place it in a vacuum oven at 60-110℃ to dry, and obtain the GPU sample.

[0080] 4. Immerse the GPU sample obtained in step 3 in a 1 wt% sodium alginate aqueous solution for 10 minutes, then immediately immerse it in a 3 wt% calcium chloride aqueous solution for 12 hours for crosslinking. Afterwards, remove the GPU sample, wash it with deionized water, and dry it at 60°C to obtain the GPU@H sample.

[0081] 5. Immerse the GPU@H sample in an immersion solution with a concentration of 20 mg / mL. -1 Soak the polystyrene in an aqueous solution of sulfonic acid for 30 minutes, then remove and dry at 80°C for 30 minutes.

[0082] 6. Repeat the crosslinking process in step 4: immerse the sample again in a 1 wt% sodium alginate solution for 10 minutes, then immerse it in a 3 wt% calcium chloride solution for 12 hours to perform crosslinking. Afterward, remove the GPU@H sample, wash it with deionized water, and dry it at 60°C for 3 hours to obtain the target product, GPU@HPS evaporation material.

[0083] The GPU@HPS evaporation material obtained in Example 4 was characterized, and the results are as follows: Figures 3-6 As shown in the figure. SEM revealed that it maintained a porous structure, but the pores were filled with gel; XRD showed characteristic peaks of graphite; FT-IR at 10¹⁰ cm⁻¹... -1 Sulfonate groups (-SO3) were found nearby. - The characteristic absorption peaks of the UV-vis spectrum show an average light absorption rate of >90% in the 250-2500 nm range.

[0084] Example 5 Performance tests were performed on the GPU@HPS evaporation material obtained in Example 4: 1. Evaporation performance test: Using AM 1.5G standard solar simulation material (1 kW·m³) -2 The GPU@HPS was placed in a flotation device with water supplied from below via absorbent cotton. Its mass loss was measured in pure water, 3.5 wt% and 20 wt% NaCl brine. Results are as follows: Figure 7 As shown, the evaporation rates under optimal conditions are 3.27, 3.53, and 3.68 kg·m³, respectively. -2 ·h -1 .

[0085] 2. Power Generation Performance Test: Two graphite electrodes (1 cm × 1 cm) were attached to the top and bottom surfaces of the GPU@HPS using conductive silver paste. The device was then placed in salt solutions of different concentrations, and the open-circuit voltage and short-circuit current were measured using a digital multimeter and a source meter under illumination. The results are as follows: Figure 8 As shown, in 20 wt% NaCl brine, the output voltage of the optimal parameter material is stable at 820 mV, and the output current is 646 μA.

[0086] Compare with Example 1 without PSS layer Referring to the preparation process in Example 4, where only steps 1 to 4 are prepared to obtain the GPU@H sample.

[0087] When tested in high-concentration brine (20 wt%), obvious salt crystals appeared on its surface within a few hours, and the open-circuit voltage was 420 mV, indicating low and unstable power generation performance.

[0088] Alternative materials compared to Example 2 Following the preparation process in Example 4, except that the polystyrene sulfonic acid aqueous solution in step 5 was replaced with a polyacrylic acid aqueous solution of equal concentration, the evaporation material was obtained.

[0089] The resulting evaporation material exhibits good hydrophilicity, but its salt resistance in high-salt water is generally poor, and its electrochemical voltage is significantly lower than that of GPU@HPS. This demonstrates the effectiveness of the sulfonate group (-SO3). - The introduction of polystyrene sulfonic acid and the sulfonate groups formed therefrom play an irreplaceable role in generating a strong negative electric field to achieve efficient ion sieving and charge separation. This indicates that the introduction of polystyrene sulfonic acid and the sulfonate groups formed therefrom are the most critical technical features of this invention to achieve the two core effects of salt-resistant crystallization under high salinity and efficient and stable power generation. The conductive graphite network and specific cross-linking process are necessary auxiliary and supporting features.

[0090] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing an integrated evaporation material for high-concentration brine desalination and power generation, characterized in that, Includes the following steps: S1: Clean and dry the polyurethane sponge; the height of the polyurethane sponge is 0.75~1.25 cm; S2: The dried polyurethane sponge is impregnated in a suspension containing conductive graphite and sodium alginate, and then dried to obtain an intermediate with a conductive graphite network; the concentration of conductive graphite in the suspension is 50-250 mg / mL. S3: The intermediate is sequentially immersed in sodium alginate solution and calcium chloride solution to perform the first crosslinking; S4: The intermediate after the first crosslinking is immersed in a polystyrene sulfonic acid solution, dried, and then immersed in sodium alginate solution and calcium chloride solution in sequence for the second crosslinking. After drying, the integrated evaporation material is obtained. The concentration of polystyrene sulfonic acid in the polystyrene sulfonic acid solution is 10-40 mg / mL.

2. The preparation method according to claim 1, characterized in that, The polyurethane foam mentioned in step S1 has a pore size of 0.5-0.6 mm and a pore count of 30-50 ppi.

3. The preparation method according to claim 1, characterized in that, The concentration of conductive graphite in the suspension in step S2 is 75~125 mg / mL; the mass fraction of sodium alginate in the suspension is 0.5-5 wt%.

4. The preparation method according to claim 1, characterized in that, In steps S3 and S4, the sodium alginate solution contains 0.5 to 3 wt% sodium alginate; and the calcium chloride solution contains 2 to 5 wt% calcium chloride.

5. The preparation method according to claim 1, characterized in that, In steps S3 and S4, the immersion time in sodium alginate solution is 5-20 minutes; the immersion time in calcium chloride solution is 10-15 hours.

6. The preparation method according to claim 1, characterized in that, The concentration of polystyrene sulfonic acid in the polystyrene sulfonic acid solution in step S4 is 15-25 mg / mL.

7. The preparation method according to claim 1, characterized in that, The immersion time in the polystyrene sulfonic acid solution in step S4 is 15-60 minutes.

8. An integrated evaporation material for high-concentration brine desalination and power generation, characterized in that, The integrated evaporation material is prepared by the method according to any one of claims 1 to 7.

9. The integrated evaporation material according to claim 8, characterized in that, The integrated evaporation material, under one solar irradiance in a 20 wt% sodium chloride solution, exhibits an evaporation rate of not less than 3.6 kg·m³. -2 ·h -1 Furthermore, there is no salt crystal accumulation on the surface.

10. A water treatment and energy harvesting system, characterized in that, The water treatment and energy harvesting system comprises the integrated evaporation material as described in claim 8 or 9, and electrodes and power management circuits electrically connected thereto for collecting the electrical energy generated during the evaporation process.

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