Porous hydrogel based on photo-thermal material as well as preparation method and application of porous hydrogel
By combining hydroxylated multi-walled carbon nanotubes with porous hydrogels containing Mxene and polymers, the performance instability of hydrogel evaporators in seawater desalination due to the influence of microorganisms and salt ions was solved, achieving efficient, antibacterial, and salt-resistant photothermal evaporation.
Patent Information
- Application Number
- CN202511808035.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-02-06
AI Technical Summary
Existing hydrogel evaporators are susceptible to microbial adhesion and salt ion effects during seawater desalination, leading to unstable performance, reduced evaporation efficiency, and easy failure.
Hydroxylated multi-walled carbon nanotubes and Mxene were combined with polymers to enhance the mechanical properties of the hydrogel through hydrogen bonding and electrostatic interactions. Foaming agents and antibacterial agents were added to prepare a porous photothermal hydrogel, which utilizes electrostatic effects and antibacterial properties to inhibit microbial adhesion and salt ion accumulation.
It improves the photothermal conversion efficiency and evaporation rate of hydrogels, enhances antibacterial properties and salt resistance, and maintains long-term stability and high-efficiency evaporation performance.
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Figure CN121471542A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of hydrogel, in particular to a porous hydrogel based on photothermal material and a preparation method and application thereof. BACKGROUND
[0002] Solar seawater desalination is to use solar energy to heat seawater, evaporate it, and then condense the steam into fresh water. The main methods can be divided into direct method and indirect method. Using solar energy to realize seawater desalination has the advantages of not consuming conventional energy, not producing secondary pollution, and low operation cost, which has important value for promoting the sustainable development of China's seawater desalination industry and energy saving and emission reduction. The interfacial solar evaporation (ISE) technology based on solar energy places photothermal materials on the water surface to realize local heating and rapid evaporation of water, which significantly reduces the overall energy consumption, and has the advantages of adjustable structure and simple process, and gradually becomes a new strategy for seawater desalination.
[0003] Hydrogel has been widely used in interfacial evaporation systems due to its excellent water absorption, three-dimensional porous structure and controllable performance, and has become a potential photothermal water evaporation material. The photothermal interfacial evaporator based on hydrogel can realize high solar absorption, efficient photothermal conversion, heat localization, rapid water transportation and water activation under natural light, and is an ideal porous structure evaporator.
[0004] However, when the hydrogel evaporator is actually applied, it will be in contact with sewage and seawater in a large area. There are usually a large number of microorganisms (such as bacteria) in these waters. Bacteria and other microorganisms can adhere, accumulate and colonize on various surfaces of different materials, and heterogeneous porous materials are the first choice for microorganism adsorption and parasitism. After the hydrogel is in contact with sewage, the rapid adsorption and reproduction of microorganisms will change the original structure of the evaporator and induce the formation of biofilm on the evaporator, resulting in blockage of water transportation channels, reduction of evaporation efficiency, instability of performance, and even degradation of photothermal materials, ultimately leading to failure of the evaporator. At the same time, seawater contains salt ions. In the simulation of seawater interfacial evaporation experiment, salt ions will crystallize on the evaporation surface, thereby affecting the light absorption of the hydrogel evaporator and reducing the performance of the evaporator.
[0005] Therefore, it is an urgent need in the practical application of solar evaporation technology to develop a porous hydrogel with high photothermal conversion efficiency and high seawater desalination rate, as well as anti-fouling property and salt resistance. SUMMARY
[0006] The purpose of the present application is to solve the above problems, and provide a porous hydrogel based on photothermal material and a preparation method and application thereof.
[0007] The first aspect of the present application provides a preparation method of a porous hydrogel based on a photothermal material, which adopts the following technical scheme:
[0008] A preparation method of a porous hydrogel based on a photothermal material, comprising the following steps:
[0009] S1, hydroxylated multi-walled carbon nanotubes (MWCNTs-OH) and Mxene are added to water and ultrasonic treatment is performed to obtain a CNT / Mxene suspension;
[0010] S2, sodium alginate (SA) and polyacrylic acid sodium (PAAS) are added to the suspension obtained in S1, and after stirring, a black slurry is obtained; sodium dodecyl sulfate (SDS) is added to the black slurry, and mechanical stirring is performed to obtain an expanded and foamed mixture;
[0011] S3, the mixture obtained in S2 is transferred into a mold, calcium chloride is sprayed, and then frozen; after freezing is completed, calcium chloride is added dropwise to the mixture until the mixture is completely immersed in the calcium chloride solution at room temperature; after physical crosslinking at room temperature, a hydrogel is formed;
[0012] S4, the hydrogel obtained in S3 is washed with deionized water to remove calcium ions on the surface, and then the hydrogel is soaked in a polyhexamethylene bromide hydrochloride (PHMB) solution to obtain a porous hydrogel based on a photothermal material (SCP hydrogel).
[0013] By adopting the above technical scheme, MXene (especially Ti3C2T x) In the near-infrared region (NIR-I and NIR-II), it has very high light absorption and excellent light-heat conversion efficiency, and can also be dispersed as a nano-enhanced filler in the hydrogel network, combined with the polymer chain through hydrogen bonding, electrostatic interaction or coordination bonding, significantly improving the mechanical strength, toughness, modulus and fatigue resistance of the hydrogel, and the hydrophilic surface of MXene and the nanochannel constructed by it can adjust the transport behavior of water molecules in the hydrogel, which is beneficial to the rapid supply of water and vapor escape in the interface evaporation application. Carbon nanotubes themselves have good light absorption and light-heat conversion capability in a wide spectral range (especially NIR), and the hydroxyl group greatly improves the dispersibility and stability of CNTs in aqueous environment and hydrogel precursor solution, like MXene, well-dispersed H-CNTs can be used as a nano-enhancing body, by bridging polymer chains, hindering micro-crack propagation, etc., significantly improving the strength, modulus and toughness of the hydrogel, the combination of the two can provide higher overall light-heat conversion efficiency and temperature rise, the presence of the two nanomaterials and their interaction with the polymer network help to stabilize the structure of the hydrogel, reduce dehydration shrinkage, and improve long-term use stability. With SDS as the foaming agent, the porous photothermal hydrogel is prepared by introducing air through vigorous stirring, avoiding the problems of swelling caused by repeated freeze-thawing, etc., the porous network structure provides strong capillary force, which can quickly pump the water below to the evaporation surface, diluting the local salt concentration, and a large number of fixed negative charges are generated by the ionization of sodium polyacrylate, forming a Donnan effect, repelling Cl- in seawater, inhibiting the local enrichment of NaCl, and binding part of Na+, in addition, the quaternary ammonium salt structure of PHMB also inhibits the enrichment of NaCl, and the cations of PHMB combine with the negative groups on the bacterial cell wall, destroying the integrity of the cell membrane and killing the bacteria, the operation is simple, and the photothermal hydrogel prepared by freeze-crosslinking and electrostatic self-assembly technology improves the evaporation rate, salt resistance and antibacterial performance.
[0014] Preferably, in S1, the amount ratio of MWCNTs-OH and Mxene is 1:1.
[0015] Preferably, in S2, the amount ratio of SA and PAAS is 2: (0-2), and further preferably 2:1.
[0016] Preferably, in S2, the amount ratio of SDS and SA is 1:1.
[0017] Preferably, in the preparation method, S1 is specifically: S1, 0.2g of MWCNTs-OH and 0.2g of Mxene are added to 40mL of deionized water and ultrasonicated for 1h to obtain a uniform CNT / mxene suspension.
[0018] Preferably, in the technical scheme of the preparation method, the step S2 is specifically: S2, 2g of SA and 1g of PAAS are added to the suspension obtained in S1, and a black slurry is obtained after stirring for 3h, 0.2g of sodium dodecyl sulfate is added to the black slurry, and a swelling and foaming mixture is obtained by mechanical stirring.
[0019] Preferably, in the technical scheme of the preparation method, the step S3 is specifically: S3, the mixture obtained in S2 is transferred into a mold, 0.5wt% of calcium chloride is sprayed for 2-3 times, and then the mixture is placed in a refrigerator, frozen at (-25℃) for 8h, and then 0.9M of calcium chloride is added dropwise to the mixture until the mixture is completely immersed in the calcium chloride solution at room temperature, and the hydrogel is formed after physical crosslinking at room temperature for 12h.
[0020] Preferably, in the technical scheme of the preparation method, the step S4 is specifically: S4, the hydrogel obtained in S3 is repeatedly washed with deionized water to remove the surface calcium ions, and then the hydrogel is soaked in a 0.5wt% PHMB solution for 12h to obtain a porous hydrogel based on a photothermal material (SCP hydrogel).
[0021] By adopting the operation steps and parameters of the preferred preparation method, a porous hydrogel with better performance is obtained.
[0022] The second aspect of the application provides a porous hydrogel based on a photothermal material, which is prepared by any one of the above preparation methods.
[0023] The third aspect of the application provides the application of the above porous hydrogel based on a photothermal material in the field.
[0024] In summary, the present application has at least one of the following beneficial technical effects:
[0025] 1. The two photothermal materials can provide higher overall photothermal conversion efficiency and temperature rise, and the presence of the two nanomaterials and their interaction with the polymer network help to stabilize the structure of the hydrogel, reduce dehydration shrinkage, and improve long-term use stability.
[0026] 2. By using SDS as a foaming agent, the porous photothermal hydrogel is prepared by introducing air through vigorous stirring, which avoids the problems of swelling caused by repeated freeze-thawing.
[0027] 3. The porous network structure provides strong capillary force, which can quickly pump the underlying water to the evaporation surface, dilutes the local salt concentration, and the ionization of sodium polyacrylate generates a large number of fixed negative charges, forming a Donnan effect, repelling Cl- in seawater, inhibiting the local enrichment of NaCl, and binding part of Na+, in addition, the quaternary ammonium salt structure of PHMB also inhibits the enrichment of NaCl, and the cations of PHMB combine with the negative groups of the bacterial cell wall, destroy the integrity of the cell membrane, and kill the bacteria, thereby improving the evaporation rate, salt resistance and antibacterial performance of the hydrogel.
[0028] 4. The porous hydrogel provided by the method has an evaporation rate of 3.03 kg·m -2 ·h -1 in pure water, maintains an evaporation rate of 2.43 kg·m -2 ·h -1 in 20% salt water, and has no visible colonies after 18h of dynamic contact with E. coli, with an antibacterial rate of 99%.
[0029] 5. The porous hydrogel provided by the method can realize self-floating as an evaporator, which can save costs in practical application. BRIEF DESCRIPTION OF DRAWINGS
[0030] Figure 1 is a graph of the evaporation rate test results of the hydrogel prepared in Examples 1-3 of the present application;
[0031] Figure 2 is a comparison graph of the water mass loss of the hydrogel prepared in Example 2 of the present application in 1kW / m -2 simulated sunlight for 1h of interfacial evaporation;
[0032] Figure 3 is a comparison graph of the evaporation rate of the hydrogel prepared in Example 2 of the present application in different concentrations of salt water;
[0033] Figure 4 is a graph of the water mass loss of the hydrogel prepared in Example 2 of the present application in 20wt% sodium chloride aqueous solution for 8h of interfacial evaporation;
[0034] Figure 5 is a graph of the antibacterial performance test results of SCP2, wherein, Figure 5 A is a photograph of the culture medium after dilution 10 3 times and coating of the control group (E. coli), Figure 5 B is a photograph of the culture medium after dilution 10 3 times and coating of the culture medium after 18h of dynamic contact between SCP2 and E. coli;
[0035] Figure 6 is a SEM graph of SCP2, wherein,Figure 6 A、 Figure 6 B and Figure 6 C are SEM images at 70, 200 and 300 times magnification, respectively;
[0036] Figure 7 is a real object picture of the self-floating performance detection of SCP2. DETAILED DESCRIPTION
[0037] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. Any modification or equivalent replacement made by those skilled in the art on the basis of the technical solutions of the present application without departing from the spirit and scope of the technical solutions of the present application should be covered within the protection scope of the present application.
[0038] The reagent information used in the following examples is as follows, all reagents and chemicals are used as received without further treatment, and other specific conditions not mentioned are carried out according to the conventional conditions or the conditions recommended by the manufacturer, and the reagents or instruments not mentioned by the manufacturer are conventional products that can be purchased on the market.
[0039] Main reagents:
[0040] Sodium alginate (SA, AR), sodium polyacrylate (PAAS, average molecular weight 4-5 million), anhydrous calcium chloride (CaCl2), sodium dodecyl sulfate (SDS) were purchased from Shanghai Ruonan Reagent;
[0041] Hydroxylated multi-walled carbon nanotubes (MWCNTs-OH) were purchased from Suzhou Carbon Fortune Technology;
[0042] Mxene (Ti3AlC2) was purchased from Xin'anyi Technology.
[0043] The chemical abbreviations in this application and the Chinese interpretation are as follows:
[0044] Hydroxylated multi-walled carbon nanotubes (MWCNTs-OH), two-dimensional transition metal carbide / nitride (Mxene, its chemical formula is M n+1 X n T x (wherein n is generally 1, 2 or 3), wherein M is an early transition metal (such as Ti, V, Nb, Mo, etc.), X is carbon or nitrogen, T xTermination functional group of material surface, including but not limited to one or more of the following: -OH (hydroxyl), -O (oxy), -F (fluorine), etc.), sodium alginate (SA), sodium polyacrylate (PAAS), sodium dodecyl sulfate (SDS), polyhexamethylene hydrochloride (PHMB), porous hydrogel based on photothermal material (SCP hydrogel, wherein S is derived from SDS, C is derived from CNT / Mxene suspension, and P is derived from PHMB), and other unspecified materials are subject to common industry knowledge.
[0045] I. Embodiment
[0046] Ti3AlC2 is used as Mxene in all embodiments of the present application.
[0047] Embodiment 1
[0048] A method for preparing a porous hydrogel based on a photothermal material, comprising the following steps:
[0049] S1. 0.2 g of MWCNTs-OH and 0.2 g of Mxene are added to 40 mL of deionized water and ultrasonicated for 1 h to obtain a uniform CNT / mxene suspension;
[0050] S2. 2 g of SA is added to the suspension obtained in S1, and after stirring at 300 rpm for 3 h, a black slurry is obtained. 0.2 g of sodium dodecyl sulfate is added to the black slurry, and an expanded and foamed mixture is obtained after mechanical stirring at 800 rpm for 5 min;
[0051] S3. The mixture obtained in S2 is transferred to a mold, and after spraying 2-3 times with 0.5 wt% calcium chloride, it is placed in a refrigerator and frozen at -25°C for 8 h. After freezing is completed, 0.9 M calcium chloride is added dropwise to the mixture until the mixture is completely immersed in the calcium chloride solution at room temperature. After physical crosslinking at room temperature for 12 h, a hydrogel is formed;
[0052] S4. The hydrogel obtained in S3 is repeatedly washed with deionized water to remove surface calcium ions, and then immersed in a 0.5 wt% PHMB solution for 12 h to obtain a porous hydrogel based on a photothermal material (SCP hydrogel).
[0053] The shape of the finished product can be adapted to the shape of the mold. The hydrogel prepared in this embodiment is denoted as SCP1.
[0054] In other possible embodiments, MWCNTs-OH and Mxene can also be replaced by other photothermal materials, such as graphene, silver, copper oxide, and molybdenum disulfide, etc. The shape of the mold can be changed according to actual application.
[0055] Example 2
[0056] A method for preparing a porous hydrogel based on a photothermal material, which is different from example 1 in that in S2, 2g of SA and 1g of PAAS are added to the suspension obtained in S1, and the remaining steps are consistent with example 1.
[0057] The hydrogel prepared in this example is denoted as SCP2.
[0058] Example 3
[0059] A method for preparing a porous hydrogel based on a photothermal material, which is different from example 1 in that in S2, 2g of SA and 2g of PAAS are added to the suspension obtained in S1, and the remaining steps are consistent with example 1.
[0060] The hydrogel prepared in this example is denoted as SCP3.
[0061] II. Performance test experiments and results
[0062] 1. Evaporation performance
[0063] 1.1 Pure water
[0064] Prepare a beaker, pour pure water (deionized water) into the beaker, cut the prepared porous hydrogel based on a photothermal material into a cylindrical shape with a radius of 1 cm and a height of 1 cm, and wrap it with insulating polystyrene foam, and immerse the bottom of the hydrogel into the water body to perform interfacial evaporation experiments. The interfacial evaporation experiment is carried out in a laboratory environment, the temperature is 25-30℃, and the humidity is 40%.
[0065] Use a xenon lamp (Cel-S500) equipped with an AM1.5 filter to simulate sunlight for irradiation, at the same time, use a solar energy meter (SM206-Solar) to calibrate the solar light intensity to maintain at one sun (1000W / m 2 ), during the evaporation process, use a high-precision one-millionth electronic balance (AX224ZH / E) to record the mass loss of the water in the beaker during the evaporation process, and finally calculate the evaporation rate according to the following formula:
[0066]
[0067] Where V is the evaporation rate (kg / m 2 ·h);△m is the change in water mass before and after evaporation (kg); s is the evaporation area (m 2 ); t is the evaporation time (h).
[0068] The hydrogels prepared in Examples 1-3 were tested according to the above method, the evaporation time was 1 h, pure water was used as a blank control group, and the mass loss and evaporation rate were tested, respectively, and the evaporation rate test results are shown in Figure 1 , and the water mass loss results are shown in Figure 2 .
[0069] As can be seen from Figure 1 , the evaporation rates of SCP1, SCP2 and SCP3 prepared in Examples 1-3 are 2.67 kg·m -2 ·h -1 , 3.03 kg·m -2 ·h -1 , and 2.87 kg·m -2 ·h -1 , respectively, all of which are better than the evaporation rate of pure water, as can be seen from Figure 2 , the mass loss of the three hydrogels is greater than that of pure water, which is in line with the results of the evaporation rate in Figure 1 , the greater the mass loss, the more water evaporates in the hydrogel in the same time, as can be seen from the slope of the curve, the mass loss rate of SCP2 and SCP3 is faster at the beginning, and then gradually slows down, as can be seen from Figure 1 and Figure 2 , among the three groups, SCP2 has the best evaporation performance, and subsequent experiments are based on SCP2 for detection.
[0070] 1.2 Salt resistance
[0071] In order to study the effect of different salt concentrations on the porous hydrogel, deionized water and sodium chloride were used to prepare sodium chloride aqueous solutions with mass fractions of 3.5wt%, 10wt%, 15wt%, and 20wt% to replace pure water for evaporation experiments.
[0072] The experimental operation steps are consistent with the pure water evaporation test, and the evaporation rate of SCP2 in salt water is shown in Figure 3 , as can be seen from Figure 3 , as the salt concentration increases, the evaporation rate decreases, which is 2.86 kg·m -2 ·h -1 , 2.74 kg·m -2 ·h -1 , 2.52 kg·m -2 ·h -1 , and 2.43 kg·m -2 ·h -1 .
[0073] Further, a sodium chloride aqueous solution with a concentration of 20wt% was selected as the evaporation solution, and the evaporation time was 8h, to explore the stability of the hydrogel in a high-salt environment for a long time, and the mass loss detection results are as followsFigure 4 As shown in Figure 4 It can be seen that the evaporation rate remained stable in 20wt% salt water for 8h, and no obvious salt crystallization was observed on the surface of the hydrogel.
[0074] 2. Bacteriostatic performance
[0075] Using E. coli as the test strain, the SCP2 was dynamically contacted with E. coli for 18h, and then the concentration of the bacterial solution was counted by plate coating. The detection results are shown in Figure 5 , wherein Figure 5 A is the control group (E. coli) diluted 10 3 times and then coated to complete the culture medium photo, Figure 5 B is the culture medium photo after the SCP2 is diluted 10 3 times and then plated after being dynamically contacted with E. coli for 18h. As can be seen from the figure, compared with the control group, there is no visible colony in the SCP group, and the antibacterial rate reaches more than 99%.
[0076] 3. Structural characterization
[0077] The morphology and structure of SCP2 were detected by field emission scanning electron microscopy. The SEM images are shown in Figure 6 , wherein, Figure 6 A, Figure 6 B and Figure 6 C are SEM images at 70, 200 and 300 times,
[0078] As can be seen from the SEM images at three different magnifications, the SCP2 material presents a obvious porous structure, which is of great significance for the photothermal material hydrogel. It not only can provide a larger specific surface area, which is conducive to light absorption and heat conduction, but also can provide space for water molecule storage and transportation, which helps to achieve efficient water evaporation in the process of photo-thermal conversion; and the material surface shows a morphology of interweaving sheet and fibrous material, which are connected to form a stable three-dimensional network structure. This structure can enhance the mechanical strength of the material, so that it can maintain the integrity of the structure in the application process, and also provides rich reaction sites for photo-thermal conversion.
[0079] The porous structure provides a good channel for the storage and transportation of water, and the hydrogel itself has hydrophilicity and can absorb a large amount of water molecules. In the process of photo-thermal conversion, water can quickly diffuse inside the material to replenish the water lost due to evaporation, maintain the water content of the material, and thus maintain the stable photo-thermal conversion efficiency; the three-dimensional network structure formed by the interweaving of sheets and fibers is conducive to heat conduction, and the interweaving structure of sheets and fibers can maintain the stability of the structure and performance in the process of multiple photo-thermal cycles, and is not easy to collapse or deform, ensuring the reliability of its long-term use.
[0080] 4. self-floating performance
[0081] The hydrogel material was placed in the water body of a beaker, and it was found that it could realize self-floating on the water surface, and the actual figure was as shown in Figure 7 .
[0082] In summary, the porous hydrogel based on photothermal material prepared by the preparation method provided in the application can realize efficient interfacial evaporation and has excellent salt resistance and antibacterial performance, and can realize self-floating, which can save cost in actual application, and provides a new idea for the interfacial evaporator of seawater desalination.
Claims
1. A method for preparing porous hydrogels based on photothermal materials, characterized in that: Includes the following steps: S1. Hydroxylated multi-walled carbon nanotubes (MWCNTs-OH) and Mxene were added to water and sonicated to obtain a CNT / Mxene suspension; S2. Add sodium alginate (SA) and sodium polyacrylate (PAAS) to the suspension obtained in S1, stir to obtain a black slurry, add sodium dodecyl sulfate (SDS) to the black slurry, and mechanically stir to obtain an expanded and foamed mixture; S3. Transfer the mixture obtained in S2 into a mold, spray it with calcium chloride and then freeze it. After freezing, add calcium chloride dropwise onto the mixture until the mixture is completely immersed in the calcium chloride solution at room temperature. After physical cross-linking at room temperature, a hydrogel is formed. S4. The hydrogel obtained in S3 is washed with deionized water to remove calcium ions from the surface. Then the hydrogel is soaked in polyhexamethylene hydrochloride (PHMB) solution to obtain a porous hydrogel based on photothermal material (SCP hydrogel).
2. The preparation method according to claim 1, characterized in that: In S1, the ratio of MWCNTs-OH to Mxene is 1:
1.
3. The preparation method according to claim 1, characterized in that: In S2, the ratio of SA to PAAS is 2:(0 to 2), preferably 2:
1.
4. The preparation method according to claim 1, characterized in that: In S2, the ratio of SDS to SA is 1:
1.
5. The preparation method according to claim 1, characterized in that: S1. Add 0.2g of MWCNTs-OH and 0.2g of Mxene to 40mL of deionized water and sonicate for 1h to obtain a uniform CNT / mxene suspension.
6. The preparation method according to claim 1, characterized in that: S2. Add 2g of SA and 1g of PAAS to the suspension obtained in S1, stir for 3 hours to obtain a black slurry, add 0.2g of sodium dodecyl sulfate to the black slurry, and mechanically stir to obtain an expanded and foamed mixture.
7. The preparation method according to claim 1, characterized in that: S3. Transfer the mixture obtained in S2 into a mold, spray it with calcium chloride with a mass percentage concentration of 0.5 wt% 2 to 3 times, and then place it in a refrigerator and freeze it at (-25℃) for 8 hours. After freezing, add calcium chloride with a molar concentration of 0.9 M dropwise to the mixture until the mixture is completely immersed in the calcium chloride solution at room temperature. After physical cross-linking at room temperature for 12 hours, a hydrogel is formed.
8. The preparation method according to claim 1, characterized in that: S4. The hydrogel obtained in S3 is repeatedly washed with deionized water to remove calcium ions from the surface. Then, the hydrogel is soaked in a PHMB solution with a mass percentage concentration of 0.5 wt% for 12 h to obtain a porous hydrogel based on photothermal material (SCP hydrogel).
9. A porous hydrogel based on photothermal materials, characterized in that: It is prepared by the preparation method according to any one of claims 1-8.
10. The application of a porous hydrogel based on photothermal materials according to claim 9 in the field of seawater desalination.