Composite hydrogel evaporator with chemical-photo-thermal synergistic antibacterial function and preparation of composite hydrogel evaporator

Abstract

The invention belongs to the field of seawater desalination, and particularly relates to a composite hydrogel evaporator with a chemical-photo-thermal synergistic antibacterial function and a preparation method of the composite hydrogel evaporator. In order to solve the problems of marine biological pollution and the like of an existing hydrogel evaporator in the seawater evaporation process, high-entropy alloy nanoparticles and hydrogel are subjected to homogenization compounding, the molecular weight range of the hydrogel is 10000-100000, the mass ratio of a hydrogel matrix to the high-entropy alloy nanoparticles is 100: (1-10), physical cross-linking curing is conducted for 6-24 h at the temperature of-50 DEG C to 0 DEG C, and the high-entropy alloy nanoparticles are obtained. The composite hydrogel evaporator with the chemical-photo-thermal synergistic antibacterial function is obtained. When the composite hydrogel evaporator is used for seawater desalination, the composite hydrogel evaporator has photo-thermal antibacterial ability and can resist microbial pollution in seawater.

Description

Technical Field

[0001] The present invention belongs to the field of seawater desalination, and in particular relates to a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties and a preparation method thereof. Background Art

[0002] Desalination technologies already in use can be categorized into three types: thermal distillation and membrane osmosis technologies that rely on fossil energy; novel distillation technologies that rely on green energy sources such as wind and geothermal energy; and solar-powered desalination technologies. Solar-powered desalination technology, with its minimal centralized requirements, zero carbon dioxide emissions, widespread availability, and low cost, has become a research hotspot. Photothermal interfacial evaporation, developed to improve solar energy efficiency and desalination rates, has become a relatively mature desalination method. Photothermal interfacial evaporation converts light into heat through light absorbers floating on the water surface, heating and evaporating only at the gas-liquid interface. This has increased the photothermal conversion efficiency from 40%-50% to over 90%, providing an effective solution to freshwater resource shortages.

[0003] Hydrogel-based photothermal interfacial evaporators (PTEs) are ideal porous evaporators, achieving high solar absorption, efficient photothermal conversion, heat localization, rapid water transport, and water activation under natural sunlight. In practical applications, hydrogel evaporators come into contact with large areas of wastewater and seawater, which often harbor a large number of microorganisms (such as bacteria). These microorganisms can attach, accumulate, and colonize on a variety of surfaces, making heterogeneous porous materials a prime candidate for microbial adsorption and parasitism. Upon contact with wastewater, the rapid adsorption and proliferation of microorganisms alters the evaporator's original structure and induces the formation of biofilms on the evaporator. This can lead to blockage of water transport channels, reduced evaporation efficiency, unstable performance, and even degradation of the PTE material, ultimately causing evaporator failure. Therefore, developing a porous hydrogel evaporator with high PTE efficiency, high desalination rate, and anti-fouling properties is an urgent need for practical applications of solar evaporation technology. Summary of the Invention

[0004] To address the current major technical challenges, the present invention provides a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties and a method for its preparation. Its core objective is to directly impart microbial resistance to photothermal materials through a simple process flow. This allows for the efficient and convenient preparation of a composite hydrogel evaporator with high photothermal conversion efficiency, high desalination rate, and antifouling properties, overcoming the limitations of large-scale application of photothermal interfacial water evaporators.

[0005] High-entropy alloys (HEAs) are alloys composed of five or more metals in equal or approximately equal amounts. Due to the controllable composition and structure, efficient light absorption across the entire spectral range from 300nm to 2500nm can be achieved through rational element design and particle size control. Without compromising light absorption performance, the simultaneous introduction of antimicrobial elements (such as Cu and Ag) can create integrated photothermal conversion materials that combine efficient photothermal conversion with chemical antimicrobial properties. This design approach will help overcome the limitations of conventional photothermal conversion materials in broad-spectrum sunlight absorption and innovatively integrate photothermal and bactericidal capabilities, demonstrating significant potential for application in fields requiring rapid light response, excellent photothermal conversion, and a sterile environment.

[0006] The composite hydrogel evaporator with chemical-photothermal synergistic antimicrobial function described in this invention has a hierarchical porous structure and is composed of high-entropy alloy nanoparticles and a hydrogel. The high-entropy alloy nanoparticles are composed of Fe, Ni, Ti, Cr, Mn, and Cu in equal molar ratios, with a particle size of 40-100 nm and are uniformly dispersed in the hydrogel. The hydrogel is primarily composed of cross-linked polyvinyl alcohol (PVA). The mass ratio of PVA to high-entropy alloy nanoparticles in the composite hydrogel evaporator raw material is 100:(1-10), and the molecular weight of PVA ranges from 10,000 to 100,000. When used for seawater desalination, the composite hydrogel evaporator exhibits photothermal antimicrobial capabilities and can resist microbial contamination in seawater.

[0007] The method for preparing the composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function of the present invention comprises the following steps: Step 1: preparing high entropy alloy nanoparticles composed of Fe, Ni, Ti, Cr, Mn, and Cu elements in equal molar ratios; Step 2: dissolving polyvinyl alcohol in a mixed solution of water and an organic solvent, adding high entropy alloy nanoparticles, and uniformly mixing to obtain a precursor solution; Step 3: The precursor solution is physically cross-linked and solidified to obtain the initial high entropy alloy hydrogel polymer; Step 4: Remove the organic solvent in the initial high entropy alloy hydrogel polymer to obtain a high entropy alloy hydrogel polymer, that is, a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function.

[0008] In step 1, the method for preparing high entropy alloy nanoparticles includes the following steps: Step 1-1: Using high-purity (≥99.9%) iron (Fe), nickel (Ni), titanium (Ti), chromium (Cr), manganese (Mn) and copper (Cu) metal powders in equal molar ratios as the initial raw materials, anhydrous ethanol is used as the process control agent, and mechanical alloying technology is used for ball milling to obtain high-entropy alloy microsheets; the high-entropy alloy microsheets are then processed into cylindrical preforms through a cold pressing process; the particle size of the initial raw materials is 45μm-100μm.

[0009] Step 1-2: placing the preform in a vacuum arc melting furnace, introducing a mixture of hydrogen (H2) and argon (Ar) as a plasma medium into the reaction chamber under a vacuum environment for arc discharge treatment, and passivating the product obtained by the arc discharge treatment to obtain high entropy alloy nanoparticles; The vacuum degree of the vacuum environment is ≤5×10 -3 Pa, to establish an oxygen-free environment; the volume ratio of hydrogen to argon in the mixed gas is 4:1; The arc discharge time is 5 minutes to 30 minutes, the voltage is 66V, the current is 180A to 250A, and the cooling substrate temperature is 7°C to 10°C to maintain non-equilibrium solidification conditions. The high-entropy alloy microsheets are melted by smelting and transformed into nanoparticles by condensation growth. Passivation refers to exposing the product obtained by arc discharge treatment to air for 6h-12h to form an oxide film on its surface to stabilize the surface properties, and finally obtain high-entropy alloy nanoparticles with a particle size range of 40nm-100nm; after the passivation is completed, it is isolated from the air and sealed for storage.

[0010] In the precursor solution of step 2, the mass ratio of polyvinyl alcohol to high-entropy alloy nanoparticles is 100:(1-10); the mass ratio of the total mass of the organic solvent and water to the polyvinyl alcohol is 100:(10-80); the mass ratio of the organic solvent to water is 100:(1-10); the molecular weight of the polyvinyl alcohol is in the range of 10,000-100,000; and the organic solvent is dimethyl sulfoxide (DMSO); In step 2, the dissolution temperature of polyvinyl alcohol is 50° C.-120° C., so that the polyvinyl alcohol is fully stretched and completely dissolved; after adding the high entropy alloy nanoparticles, stirring is continued for 1 h-5 h, and a precursor solution is obtained after mixing evenly.

[0011] In step 3, the temperature for physical crosslinking and curing is -50°C to 0°C, and the reaction time is 6h to 24h, so that the polyvinyl alcohol is physically crosslinked and cured to form a solid gel.

[0012] In step 4, the initial high entropy alloy hydrogel polymer is immersed in deionized water at 15°C-30°C for 1h-12h until the organic solvent is completely replaced and removed by the deionized water, thereby obtaining a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function, which is stored in deionized water for future use.

[0013] By precisely selecting the constituent elements of high-entropy alloys, the present invention positions the 3D energy bands of different elements near the Fermi level, achieving a novel integrated photothermal conversion material that combines efficient photothermal conversion with synergistic antibacterial properties in response to full-spectrum sunlight. A composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties is constructed using hydrogels. The high-strength hydrogel evaporator has an absorption rate of up to 97.2% for sunlight, a kill rate of over 99% for both Gram-positive and Gram-negative bacteria under illumination, and a water evaporation rate of 2.4 kg·m -2 ·h -1 , providing a new idea and technical approach for the research and development of photothermal interface hydrogel evaporator.

[0014] Compared with the prior art, the present invention has the following beneficial effects: Compared to single-element metal particles, composite hydrogel evaporators incorporating high-entropy alloy nanoparticles exhibit superior performance in terms of absorbance, antibacterial efficiency, and material stability. 1. Absorbance: High-entropy alloy nanoparticles enhance light absorption through the synergistic effect of multiple elements. Their unique lattice distortion and interband transition effect (dd-interband absorption) significantly broaden the absorption range of the solar spectrum, thereby improving photothermal conversion efficiency. In contrast, single-element metal particles typically have a narrow absorption spectrum (for example, Cu only strongly absorbs visible light) and lack the band-modulating properties of multi-element synergy, resulting in lower photothermal efficiency and a weaker photothermal response. Therefore, evaporators incorporating high-entropy alloy nanoparticles exhibit higher water evaporation rates. 2. Antibacterial Efficiency: Photothermal heating not only directly destroys bacterial structure but also inhibits bacterial metabolism through a heat shock effect, while also enhancing copper ion diffusion and ROS generation. However, due to the lack of photothermal synergy, the antibacterial activity of single-element particles is limited to a single chemical or physical mechanism. Therefore, evaporators incorporating high-entropy alloy nanoparticles exhibit superior antibacterial efficacy. 3. Material stability and long-term effectiveness: The high entropy effect (high configurational entropy) of high-entropy alloy nanoparticles inhibits elemental phase separation and oxidation tendencies, ensuring that the nanoparticles maintain structural stability during long-term use, while single-element particles may experience performance degradation due to oxidation or agglomeration.

[0015] The present invention prepares a high-entropy alloy by compounding metal elements with different characteristics, giving the high-entropy alloy a more efficient photothermal conversion performance compared to traditional materials, and introducing antibacterial elements to achieve an innovative and stable integration of the material's photothermal and antibacterial properties. The high-entropy alloy nanoparticles provided by the present invention have good compatibility with the hydrogel matrix and can be evenly distributed in the hydrogel matrix; at the same time, the high-entropy alloy nanoparticles do not react with the hydrogel components and have physical and chemical stability. The composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function provided by the present invention has excellent water evaporation capacity, can maintain good steam generation performance in bacterial solutions, and has good stability to meet application requirements under complex conditions.

[0016] The present invention selects hydrogel as the matrix material of the evaporator to obtain hydrophilicity and porosity, thereby accelerating water transfer; introduces antibacterial elements into the hydrophilic photothermal high-entropy alloy that has been fully designed to achieve dd orbital transitions, thereby realizing the stable integration of photothermal materials and antibacterial materials; the high-entropy alloy uniformly dispersed in the hydrogel matrix maintains the stability of physical and chemical properties, expanding the use scenarios of the hydrogel evaporator; at the same time, the high-entropy alloy nanoparticles and the hydrogel produce a hydrophilic superposition, thereby accelerating the water evaporation rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The image of the high entropy alloy nanoparticles prepared in Example 3 of the present invention is displayed with the assistance of scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDS); Figure 2 is an X-ray photoelectron spectroscopy (XPS) graph of the high entropy alloy nanoparticles prepared in Example 3 of the present invention; Figure 3 is an X-ray diffraction (XRD) pattern of high entropy alloy nanoparticles prepared in Example 3 of the present invention; Figure 4 is an X-ray diffraction (XRD) pattern of the sample; HEA is the high entropy alloy nanoparticles prepared in Example 3, HEA-PVA is the composite hydrogel evaporator prepared in Example 3, and PVA is the hydrogel evaporator prepared in Comparative Example 1; Figure 5 is an absorption spectrum curve of the sample; HEA is the high entropy alloy nanoparticles prepared in Example 3, HEA-PVA is the composite hydrogel evaporator prepared in Example 3, and PVA is the hydrogel evaporator prepared in Comparative Example 1; Figure 6 : is a water evaporation weight loss curve of the sample; wherein, HEA-PVA is the composite hydrogel evaporator prepared in Example 3, and PVA is the hydrogel evaporator prepared in Comparative Example 1; Figure 7 : These are the anti-Pseudomonas aeruginosa effect diagrams of the samples; wherein, (a) is the hydrogel evaporator prepared in Comparative Example 1, (b) is the composite hydrogel evaporator prepared in Example 3, and (c) is the composite hydrogel evaporator prepared in Example 3 after being irradiated with sunlight; Figure 8 : These are diagrams showing the anti-Vietnamese Bacillus effect of the samples; wherein, (a) is the hydrogel evaporator prepared in Comparative Example 1, (b) is the composite hydrogel evaporator prepared in Example 3, and (c) is the composite hydrogel evaporator prepared in Example 3 after being irradiated with sunlight. DETAILED DESCRIPTION

[0018] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below with reference to the accompanying drawings and preferred embodiments.

[0019] Experimental methods without specifying specific conditions are generally performed under conventional conditions, such as those described in textbooks and experimental manuals, or according to the conditions recommended by the manufacturer, which are well known or easily known to those skilled in the art. The following examples are only preferred embodiments of the present invention and do not limit the present invention. For those skilled in the art, the present invention may be subjected to various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0020] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0021] Example 1 The composite hydrogel evaporator is composed of high-entropy alloy nanoparticles composed of Fe, Ni, Ti, Cr, Mn, and Cu elements in equal molar ratios and polyvinyl alcohol hydrogel. The mass ratio of polyvinyl alcohol to high-entropy alloy nanoparticles in the evaporator raw materials is 100:6.7, and the molecular weight of polyvinyl alcohol is 10,000.

[0022] The preparation method of the composite hydrogel evaporator is as follows: Step 1: Prepare high entropy alloy nanoparticles. The specific steps are as follows: Step 1-1: Using Fe, Ni, Ti, Cr, Mn, and Cu metal powders with a purity of not less than 99.9% and a particle size of approximately 80 μm as raw materials, these metal powders were mixed in equal molar ratios and subjected to high-energy ball milling in an omnidirectional planetary ball mill using anhydrous ethanol as a process aid at 350 rpm, with a ball-to-material ratio of 10:1, to produce high-entropy alloy microplates. These high-entropy alloy microplates were then stamped into cylindrical preforms measuring 10 mm x 5 mm in diameter.

[0023] Step 1-2: After creating an oxygen-free environment in a vacuum arc furnace, place the cylindrical preform high entropy alloy micro-chip in the vacuum chamber of the arc furnace for arc discharge treatment. -3At 1.5 Pa, the reaction gases H₂ and Ar were introduced into the furnace chamber at a volume ratio of 4:1. The reaction voltage was adjusted to 66 V and the reaction current was 230 A. The arc discharge process lasted for 30 minutes, transforming the high-entropy alloy microplatelets into nanoparticles through melting. The temperature of the cooling substrate was set at 10°C, creating a non-equilibrium synthesis environment that promoted the condensation growth of the high-entropy alloy and the formation of nanoparticles. After completing these steps, a passivation treatment was performed. The product obtained by the arc discharge treatment was exposed to air for 6 hours to form an oxide film on the surface to stabilize the surface properties and to allow the nanoparticles to settle before being collected. The result was the successful acquisition of high-entropy alloy nanoparticles with a particle size of 40 nm.

[0024] Step 2: Dissolve 0.15 g of polyvinyl alcohol with a molecular weight of 10,000 in a mixed solution of 0.1 g of water and 1 g of dimethyl sulfoxide, heat to 90°C and stir magnetically. After the polyvinyl alcohol is completely dissolved, add 0.01 g of high-entropy alloy nanoparticles and continue stirring for 1 hour. After mixing evenly, a precursor solution is obtained.

[0025] Step 3: The homogenized precursor solution was injected into a homemade polytetrafluoroethylene mold at a high temperature of 90°C. The mold was then transferred to a low-temperature environment of -50°C to allow the polyvinyl alcohol to undergo physical crosslinking and form a solid gel. This low-temperature polymerization took 6 hours. After the reaction was complete, the solid gel was removed from the mold to obtain the initial high-entropy alloy hydrogel polymer.

[0026] Step 4: Immerse the initial high entropy alloy hydrogel polymer in deionized water at room temperature of 15°C for 1 hour until the organic solvent is completely replaced by deionized water to obtain a high entropy alloy hydrogel polymer, that is, a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function; store it in deionized water for later use.

[0027] Example 2 The composite hydrogel evaporator is composed of high-entropy alloy nanoparticles composed of Fe, Ni, Ti, Cr, Mn, and Cu elements in equal molar ratios and polyvinyl alcohol hydrogel. The mass ratio of polyvinyl alcohol to high-entropy alloy nanoparticles in the evaporator raw material is 100:5, and the molecular weight of polyvinyl alcohol is 20,000.

[0028] The preparation method of the composite hydrogel evaporator is as follows: Step 1: Prepare high entropy alloy nanoparticles. The specific steps are as follows: Step 1-1: Using Fe, Ni, Ti, Cr, Mn, and Cu metal powders with a purity of no less than 99.9% and a particle size of approximately 50 μm as raw materials, these metal powders were mixed in equal molar ratios and subjected to high-energy ball milling in an omnidirectional planetary ball mill using anhydrous ethanol as a process aid at 350 rpm, with a ball-to-material ratio of 10:1, to produce high-entropy alloy microplates. These high-entropy alloy microplates were then stamped into cylindrical preforms measuring 10 mm x 5 mm in diameter.

[0029] Step 1-2: After creating an oxygen-free environment in a vacuum arc furnace, place the cylindrical preform high entropy alloy micro-chip in the vacuum chamber of the arc furnace for arc discharge treatment. -3 At 100 Pa, the reaction gases H₂ and Ar were introduced into the furnace chamber at a volume ratio of 4:1. The reaction voltage was adjusted to 66 V and the reaction current was 200 A. The arc discharge process lasted for 5 minutes, transforming the high-entropy alloy microplatelets into nanoparticles through melting. The temperature of the cooling substrate was set at 7°C, creating a non-equilibrium synthesis environment that promoted the growth of high-entropy alloy nuclei and the formation of nanoparticles. After completing these steps, a passivation treatment was performed. The product obtained by arc discharge treatment was exposed to air for 12 hours to form an oxide film on the surface to stabilize the surface properties and to allow the nanoparticles to settle before being collected. The result was the successful acquisition of high-entropy alloy nanoparticles with a particle size of 70 nm.

[0030] Step 2: Dissolve 0.4 g of polyvinyl alcohol with a molecular weight of 20,000 in a mixed solution of 0.1 g of water and 2 g of dimethyl sulfoxide, heat to 120°C and stir magnetically. After the polyvinyl alcohol is completely dissolved, add 0.02 g of high-entropy alloy nanoparticles and continue stirring for 5 hours. After mixing evenly, a precursor solution is obtained.

[0031] Step 3: The homogenized precursor solution was injected into a homemade polytetrafluoroethylene mold at a high temperature of 120°C. The mold was then transferred to a low-temperature environment of 0°C to allow the polyvinyl alcohol to undergo physical crosslinking and form a solid gel. This low-temperature polymerization took 24 hours. After the reaction was complete, the solid gel was removed from the mold to obtain the initial high-entropy alloy hydrogel polymer.

[0032] Step 4: Immerse the initial high entropy alloy hydrogel polymer in deionized water at room temperature of 30°C for 12 hours until the organic solvent is completely replaced by deionized water to obtain a high entropy alloy hydrogel polymer, that is, a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function; store it in deionized water for later use.

[0033] Example 3 The composite hydrogel evaporator is composed of high-entropy alloy nanoparticles composed of Fe, Ni, Ti, Cr, Mn, and Cu elements in equal molar ratios and polyvinyl alcohol hydrogel. The mass ratio of polyvinyl alcohol to high-entropy alloy nanoparticles in the evaporator raw materials is 100:2.5, and the molecular weight of polyvinyl alcohol is 20,000.

[0034] The preparation method of the composite hydrogel evaporator is as follows: Step 1: Prepare high entropy alloy nanoparticles. The specific steps are as follows: Step 1-1: Using Fe, Ni, Ti, Cr, Mn, and Cu metal powders with a purity of not less than 99.9% and a particle size of approximately 45 μm as raw materials, these metal powders were mixed in equal molar ratios and subjected to high-energy ball milling in an omnidirectional planetary ball mill using anhydrous ethanol as a process aid at 350 rpm, with a ball-to-material ratio of 10:1, to produce high-entropy alloy microplates. These high-entropy alloy microplates were then stamped into cylindrical preforms measuring 10 mm x 5 mm in diameter.

[0035] Step 1-2: After creating an oxygen-free environment in a vacuum arc furnace, place the cylindrical preform high entropy alloy micro-chip in the vacuum chamber of the arc furnace for arc discharge treatment. -3 At 1.5 Pa, the reaction gases H₂ and Ar were introduced into the furnace chamber at a volume ratio of 4:1. The reaction voltage was adjusted to 66 V and the reaction current was 180 A. The arc discharge process lasted for 20 minutes, transforming the high-entropy alloy microplatelets into nanoparticles through melting. The temperature of the cooling substrate was set at 8°C, creating a non-equilibrium synthesis environment that promoted the growth of high-entropy alloy nuclei and the formation of nanoparticles. After completing these steps, a passivation treatment was performed. The product obtained by arc discharge treatment was exposed to air for 8 hours to form an oxide film on the surface to stabilize the surface properties and to allow the nanoparticles to settle before being collected. The result was the successful acquisition of high-entropy alloy nanoparticles with a particle size of 60 nm.

[0036] Step 2: Dissolve 2 g of polyvinyl alcohol with a molecular weight of 20,000 in a mixed solution of 0.5 g of water and 8 g of dimethyl sulfoxide, heat to 100°C and stir magnetically. After the polyvinyl alcohol is completely dissolved, add 0.05 g of high-entropy alloy nanoparticles and continue stirring for 3 hours until the mixture is evenly mixed to obtain a precursor solution.

[0037] Step 3: The homogenized precursor solution was injected into a homemade polytetrafluoroethylene mold at a high temperature of 100°C. The mold was then transferred to a low-temperature environment of -30°C to allow the polyvinyl alcohol to undergo physical crosslinking and form a solid gel. This low-temperature polymerization took 12 hours. After the reaction was complete, the solid gel was removed from the mold to obtain the initial high-entropy alloy hydrogel polymer.

[0038] Step 4: Immerse the initial high entropy alloy hydrogel polymer in deionized water at room temperature of 20°C for 6 hours until the organic solvent is completely replaced by deionized water to obtain a high entropy alloy hydrogel polymer, that is, a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function; store it in deionized water for future use.

[0039] High entropy alloy nanoparticles synthesized by arc discharge melting have regular spherical structures, such as Figure 1 As shown in Figure 2, the metal elements are randomly and evenly dispersed in the nanoparticles without element segregation and phase separation. Figure 2 As shown, the elemental composition of high entropy alloy nanoparticles includes Fe, Ni, Ti, Cr, Mn and Cu elements ( Figure 2 The C and O in the sample are impurities that are inevitably introduced during the detection process). Figure 3 As shown, three peaks are observed at 43.14°, 49.70°, and 72.34°, corresponding to the (111), (200), and (220) planes, respectively. It can be analyzed that the crystal form of the high entropy alloy nanoparticles is a face-centered cubic structure. Figure 4 From the peak shapes and positions of HEA-PVA, HEA, and PVA, it can be seen that the composite hydrogel evaporator prepared in Example 3 has successfully composited the high entropy alloy nanoparticles in terms of crystal structure, and the combination of the hydrogel component and the high entropy alloy nanoparticles will not destroy the respective structures of the high entropy alloy nanoparticles and the hydrogel component.

[0040] Example 4 The composite hydrogel evaporator is composed of high-entropy alloy nanoparticles composed of Fe, Ni, Ti, Cr, Mn, and Cu elements in equal molar ratios and polyvinyl alcohol hydrogel. The mass ratio of polyvinyl alcohol to high-entropy alloy nanoparticles in the evaporator raw material is 100:1, and the molecular weight of polyvinyl alcohol is 50,000.

[0041] The preparation method of the composite hydrogel evaporator is as follows: Step 1: Prepare high entropy alloy nanoparticles. The specific steps are as follows: Step 1-1: Using Fe, Ni, Ti, Cr, Mn, and Cu metal powders with a purity of not less than 99.9% and a particle size of approximately 90 μm as raw materials, these metal powders were mixed in equal molar ratios and subjected to high-energy ball milling in an omnidirectional planetary ball mill using anhydrous ethanol as a process aid at 350 rpm, with a ball-to-material ratio of 10:1, to produce high-entropy alloy microplates. These high-entropy alloy microplates were then stamped into cylindrical preforms measuring 10 mm x 5 mm in diameter.

[0042] Step 1-2: After creating an oxygen-free environment in a vacuum arc furnace, place the cylindrical preform high entropy alloy micro-chip in the vacuum chamber of the arc furnace for arc discharge treatment. -3 At 1.5 Pa, the reaction gases H₂ and Ar were introduced into the furnace chamber at a volume ratio of 4:1. The reaction voltage was adjusted to 66 V and the reaction current was 220 A. The arc discharge process lasted for 15 minutes, transforming the high-entropy alloy microplatelets into nanoparticles through melting. The temperature of the cooling substrate was set at 9°C, creating a non-equilibrium synthesis environment that promoted the growth of high-entropy alloy nuclei and the formation of nanoparticles. After completing these steps, a passivation treatment was performed. The product obtained by arc discharge treatment was exposed to air for 9 hours to form an oxide film on the surface to stabilize the surface properties and to allow the nanoparticles to settle before being collected. The result was the successful acquisition of high-entropy alloy nanoparticles with a particle size of 100 nm.

[0043] Step 2: Dissolve 3 g of polyvinyl alcohol with a molecular weight of 50,000 in a mixed solution of 0.7 g of water and 9 g of dimethyl sulfoxide, heat to 80°C and stir magnetically. After the polyvinyl alcohol is completely dissolved, add 0.03 g of high-entropy alloy nanoparticles and continue stirring for 2 hours. After mixing evenly, a precursor solution is obtained.

[0044] Step 3: The homogenized precursor solution was injected into a homemade polytetrafluoroethylene mold at 80°C. The mold was then transferred to a low-temperature environment of -20°C to allow the polyvinyl alcohol to undergo physical crosslinking and form a solid gel. The low-temperature polymerization lasted for 15 hours. After the reaction was complete, the solid gel was removed from the mold to obtain the initial high-entropy alloy hydrogel polymer.

[0045] Step 4: Immerse the initial high entropy alloy hydrogel polymer in deionized water at room temperature of 25°C for 8 hours until the organic solvent is completely replaced by deionized water to obtain a high entropy alloy hydrogel polymer, that is, a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function; store it in deionized water for later use.

[0046] Example 5 The composite hydrogel evaporator is composed of high-entropy alloy nanoparticles composed of Fe, Ni, Ti, Cr, Mn, and Cu elements in equal molar ratios and polyvinyl alcohol hydrogel. The mass ratio of polyvinyl alcohol to high-entropy alloy nanoparticles in the evaporator raw material is 100:7, and the molecular weight of polyvinyl alcohol is 30,000.

[0047] The preparation method of the composite hydrogel evaporator is as follows: Step 1: Prepare high entropy alloy nanoparticles. The specific steps are as follows: Step 1-1: Using Fe, Ni, Ti, Cr, Mn, and Cu metal powders with a purity of not less than 99.9% and a particle size of approximately 90 μm as raw materials, these metal powders were mixed in equal molar ratios and subjected to high-energy ball milling in an omnidirectional planetary ball mill using anhydrous ethanol as a process aid at 350 rpm, with a ball-to-material ratio of 10:1, to produce high-entropy alloy microplates. These high-entropy alloy microplates were then stamped into cylindrical preforms measuring 10 mm x 5 mm in diameter.

[0048] Step 1-2: After creating an oxygen-free environment in a vacuum arc furnace, place the cylindrical preform high entropy alloy micro-chip in the vacuum chamber of the arc furnace for arc discharge treatment. -3 At 1.5 Pa, the reaction gases H₂ and Ar were introduced into the furnace chamber at a volume ratio of 4:1. The reaction voltage was adjusted to 66 V and the reaction current was 240 A. The arc discharge process lasted for 25 minutes, transforming the high-entropy alloy microplatelets into nanoparticles through melting. The temperature of the cooling substrate was set at 10°C, creating a non-equilibrium synthesis environment that promoted the growth of high-entropy alloy nuclei and the formation of nanoparticles. After completing these steps, a passivation treatment was performed. The product obtained by arc discharge treatment was exposed to air for 10 hours to form an oxide film on the surface to stabilize the surface properties and to allow the nanoparticles to settle before being collected. Ultimately, high-entropy alloy nanoparticles with a particle size of 75 nm were successfully obtained.

[0049] Step 2: Dissolve 1 g of polyvinyl alcohol with a molecular weight of 30,000 in a mixed solution of 0.4 g of water and 8 g of dimethyl sulfoxide, heat to 110°C and stir magnetically. After the polyvinyl alcohol is completely dissolved, add 0.07 g of high-entropy alloy nanoparticles and continue stirring for 4 hours. After mixing evenly, a precursor solution is obtained.

[0050] Step 3: The homogenized precursor solution was injected into a homemade polytetrafluoroethylene mold at a high temperature of 110°C. The mold was then transferred to a low-temperature environment of -10°C to allow the polyvinyl alcohol to undergo physical crosslinking and form a solid gel. This low-temperature polymerization took 20 hours. After the reaction was complete, the solid gel was removed from the mold to obtain the initial high-entropy alloy hydrogel polymer.

[0051] Step 4: Immerse the initial high entropy alloy hydrogel polymer in deionized water at room temperature of 25°C for 9 hours until the organic solvent is completely replaced by deionized water to obtain a high entropy alloy hydrogel polymer, that is, a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function; store it in deionized water for later use.

[0052] Comparative Example 1 The hydrogel evaporator does not contain high entropy alloy nanoparticles, and the molecular weight of polyvinyl alcohol is 20,000.

[0053] The specific preparation method of the hydrogel evaporator is as follows: Step 1: No high entropy alloy nanoparticles are prepared.

[0054] Step 2: Dissolve 2 g of polyvinyl alcohol with a molecular weight of 20,000 in a mixed solution of 0.5 g of water and 8 g of dimethyl sulfoxide, heat to 100° C. and perform magnetic stirring, and stir for 3 hours until the polyvinyl alcohol is completely dissolved to obtain a precursor solution.

[0055] Step 3: The precursor solution was injected into a homemade polytetrafluoroethylene mold at a high temperature of 100°C. The mold was then transferred to a low-temperature environment of -30°C to allow the polyvinyl alcohol to undergo physical crosslinking and form a solid gel. This low-temperature polymerization took 12 hours. After the reaction was complete, the solid gel was removed from the mold to obtain the initial hydrogel polymer.

[0056] Step 4: Immerse the initial hydrogel polymer in deionized water at room temperature of 20° C. for 6 hours until the organic solvent is completely replaced by the deionized water to obtain a hydrogel polymer, i.e., a hydrogel evaporator; store the resulting polymer in deionized water for later use.

[0057] Comparative Example 2 The composite hydrogel evaporator does not contain high-entropy alloy nanoparticles, but is composed of Fe, Ni, Ti, Cr, Mn, Cu metal element powders and polyvinyl alcohol hydrogel in equal molar ratios. The total mass ratio of polyvinyl alcohol to metal element powder in the evaporator raw material is 100:2.5, and the molecular weight of polyvinyl alcohol is 20,000.

[0058] The specific preparation method of the composite hydrogel evaporator is as follows: Step 1: Without preparing high entropy alloy nanoparticles, weigh Fe, Ni, Ti, Cr, Mn, and Cu metal element powders in equal molar ratios.

[0059] Step 2: Dissolve 2 g of polyvinyl alcohol with a molecular weight of 20,000 in a mixed solution of 0.5 g of water and 8 g of dimethyl sulfoxide, heat to 100°C and stir magnetically. After the polyvinyl alcohol is completely dissolved, add 0.05 g of metal element powder in total, and continue stirring for 3 hours until the mixture is evenly mixed to obtain a precursor solution.

[0060] Step 3: The homogenized precursor solution was injected into a homemade polytetrafluoroethylene mold at 100°C. The mold was then transferred to a low-temperature environment of -30°C to allow the polyvinyl alcohol to undergo physical crosslinking, forming a solid gel. This low-temperature polymerization took 12 hours. After the reaction was complete, the solid gel was removed from the mold to obtain the initial alloy hydrogel polymer.

[0061] Step 4: Immerse the initial alloy hydrogel polymer in deionized water at room temperature of 20°C for 6 hours until the organic solvent is completely replaced by deionized water to obtain the alloy hydrogel polymer, that is, a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function; store it in deionized water for future use.

[0062] Performance Analysis: 1. Solar absorption spectrum analysis: A UV-Vis-NIR spectrophotometer (UV-3600i) was used to measure the sample's absorbance within the range of 300nm-2500nm. First, the instrument was preheated to a stable state and the appropriate integrating sphere accessory sample cell was selected. Baseline correction was performed using barium sulfate as a blank reference. The sample to be tested was then evenly loaded into the sample cell, ensuring the absence of impurities, and pressed into a pellet. The scan parameters were set to 300nm-2500nm, with the slit width adjusted to 20nm, the data interval to 1nm, and the photometric value type set to reflectance. After initiating the scan, the instrument illuminated the sample step by step using a deuterium lamp (UV region) and a halogen tungsten lamp (visible-near-infrared region). The detector recorded the reflected light intensity and converted it into absorbance data.

[0063] Figure 5 The middle gray area is the solar radiation spectrum, indicating that the addition of high-entropy alloy nanoparticles greatly improves the solar absorption of the hydrogel evaporator. At the same time, high-entropy alloy nanoparticles and hydrogel components show a synergistic effect in solar absorption, which further increases the solar absorption rate of the composite hydrogel evaporator with chemical-photothermal synergistic antibacterial function to 97.2%.

[0064] 2. Analysis of water evaporation mass loss curve: A xenon lamp light source and a precision analytical balance with an accuracy of 0.0001g were used to test the water evaporation mass loss of the sample. First, the sample was placed in a constant temperature environment and the initial mass was recorded. The xenon lamp light source was turned on and adjusted to a single solar radiation intensity (AM=1.5G) to ensure that the sample surface was evenly heated. The sample was placed within the illumination range of the light source and the precision balance was set to output the current weight reading in real time every 1 minute. By continuously recording the time-mass data, the mass loss per unit time was calculated and combined with the sample surface area to finally obtain the water evaporation rate in kg·m -2 ·h -1 .

[0065] Figure 6 The absolute value of the slope of the middle curve represents the water evaporation rate. The water evaporation rates of the composite hydrogel evaporator of Example 3 and the hydrogel evaporator of Comparative Example 1 are respectively 2.4 kg·m -2 ·h -1 and 2.0 kg·m -2 ·h -1, indicating that the addition of high-entropy alloy nanoparticles greatly improved the solar light absorption rate, thereby accelerating the water evaporation rate.

[0066] 3. Analysis of antibacterial effect: The antibacterial effect was evaluated by plate coating method. First, the target bacterial solution (Pseudomonas aeruginosa or Bacillus vietnamese) was diluted to an appropriate concentration (about 10 5 CFU / mL-10 6 CFU / mL), immerse the sample in the target bacterial solution and co-culture for 24 hours. Then, using sterile PBS buffer as the liquid medium, isolate bacteria attached to the sample surface with the aid of vortexing. The bacteria are then spread onto a sterile solid culture medium. The inoculated solid culture medium is incubated upside down at 37°C in a constant temperature incubator in the dark for 18-24 hours, and the number of colonies grown is observed to assess antimicrobial activity. All experiments were performed under sterile conditions.

[0067] Depend on Figure 7 (a) Figure 7 (b) and Figure 7 (c) and Figure 8 (a) Figure 8 (b) and Figure 8 (c) It can be seen that the composite high-entropy alloy hydrogel evaporator prepared in the present invention exhibits excellent antibacterial properties, with the bacterial survival rate of co-cultured bacteria significantly lower than that of the hydrogel evaporator in Comparative Example 1. After irradiating the composite hydrogel evaporator of Example 3 for 30 minutes at a single solar intensity (other conditions were the same as those for the sample antibacterial experiment), the antibacterial rate was further increased to over 99% due to the synergistic bactericidal effect of the high-entropy alloy and the thermal effect. Furthermore, the high-entropy alloy exhibited significant antibacterial activity against Bacillus vietnamese, achieving near-complete sterilization of Bacillus vietnamese without the synergistic thermal effect.

Claims

1. A composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties, characterized in that: The composite hydrogel evaporator is composed of high-entropy alloy nanoparticles and hydrogel; the high-entropy alloy nanoparticles are composed of Fe, Ni, Ti, Cr, Mn, and Cu elements in equal molar ratios, have a particle size of 40nm-100nm, and are uniformly dispersed in the hydrogel; the hydrogel is composed of cross-linked polyvinyl alcohol; the mass ratio of the polyvinyl alcohol to the high-entropy alloy nanoparticles is 100:(1-10), and the molecular weight of the polyvinyl alcohol ranges from 10,000 to 100,000; when used for seawater desalination, the composite hydrogel evaporator has photothermal antibacterial capabilities and can resist microbial contamination in seawater.

2. The method for preparing the composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties according to claim 1, characterized in that: Includes the following: Step 1: preparing high entropy alloy nanoparticles composed of Fe, Ni, Ti, Cr, Mn, and Cu elements in equal molar ratios; Step 2: dissolving polyvinyl alcohol in a mixed solution of water and an organic solvent, adding high entropy alloy nanoparticles, and mixing uniformly to obtain a precursor solution; Step 3: The precursor solution is physically cross-linked and solidified to obtain the initial high entropy alloy hydrogel polymer; Step 4: Remove the organic solvent in the initial high entropy alloy hydrogel polymer to obtain a high entropy alloy hydrogel polymer, that is, a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties.

3. The method for preparing a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties according to claim 2, characterized in that: In step 1, the method for preparing high entropy alloy nanoparticles comprises the following steps: Step 1-1: Using Fe, Ni, Ti, Cr, Mn, and Cu metal powders in equal molar ratios as initial raw materials, ball milling is performed using a mechanical alloying technique to obtain high-entropy alloy micro-sheets; the high-entropy alloy micro-sheets are formed into a preform through a cold pressing process; Step 1-2: Under a vacuum environment, the preform is subjected to arc discharge treatment using a mixture of hydrogen and argon as a plasma medium, and the product obtained by the arc discharge treatment is passivated to obtain high entropy alloy nanoparticles.

4. The method for preparing a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties according to claim 3, characterized in that: In step 1-1, the particle size of the initial raw material is 45 μm-100 μm; in step 1-2, the particle size of the high entropy alloy nanoparticles is 40 nm-100 nm.

5. The method for preparing a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties according to claim 3, characterized in that: In step 1-2, the vacuum degree is ≤5×10 -3 Pa, the volume ratio of hydrogen to argon in the mixed gas is 4:1; the arc discharge treatment time is 5min-30min, the voltage is 66V, the current is 180A-250A, and the cooling substrate temperature is 7°C-10°C; the passivation refers to exposing the product obtained by arc discharge treatment to the air for 6h-12h to form an oxide film on the surface.

6. The method for preparing a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties according to claim 2, characterized in that: In the precursor solution of step 2, the mass ratio of the polyvinyl alcohol to the high-entropy alloy nanoparticles is 100:(1-10); the molecular weight range of the polyvinyl alcohol is 10,000-100,000; the mass ratio of the total mass of the organic solvent and water to the polyvinyl alcohol is 100:(10-80); the mass ratio of the organic solvent to water is 100:(1-10); and the organic solvent is dimethyl sulfoxide.

7. The method for preparing a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties according to claim 2, characterized in that: In step 2, the dissolution temperature is 50° C.-120° C. After the polyvinyl alcohol is completely dissolved, high entropy alloy nanoparticles are added, and the mixture is stirred for 1 h-5 h to obtain the precursor solution.

8. The method for preparing a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties according to claim 2, characterized in that: In step 3, the temperature of the physical cross-linking curing is -50°C to 0°C and the time is 6 hours to 24 hours, so that the polyvinyl alcohol is cured by physical cross-linking to form a solid gel.

9. The method for preparing a composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties according to claim 2, characterized in that: In step 4, the initial high entropy alloy hydrogel polymer is immersed in deionized water at 15° C.-30° C. for 1 h-12 h until the organic solvent is completely replaced and removed by the deionized water, thereby obtaining the composite hydrogel evaporator with chemical-photothermal synergistic antibacterial properties.

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