A core-shell superhydrophobic photothermal material and its preparation method and application

Abstract

The present invention discloses a core-shell super-hydrophobic photothermal material and its preparation method and application. The core-shell super-hydrophobic photothermal material includes activated sea sand as a core, an intermediate layer of polydopamine and an outer shell layer, and the outer shell layer includes a photothermal material and a hydrophobic material. The preparation method includes: performing an activation treatment on the sea sand to obtain activated sea sand; subjecting dopamine hydrochloride to a polymerization reaction, modifying the surface of the activated sea sand to form polydopamine, obtaining polydopamine sea sand, and then annealing; and then reacting with a coupling agent and a photothermal material monomer to obtain a core-shell super-hydrophobic photothermal material. The photothermal material provided by the present invention has spontaneous agglomeration behavior, can form a pore structure, is conducive to water evaporation during water regeneration, and also has super-hydrophobic properties and efficient sunlight absorption capacity; and the preparation method is simple in process and low in cost, providing a technical solution to the insufficient salt resistance of photothermal materials in the field of interfacial photothermal evaporation and seawater desalination.

Description

Technical Field

[0001] The present invention relates to a photothermal material, in particular to a novel core-shell super-hydrophobic photothermal material and a preparation method and application thereof, belonging to the technical field of interfacial photothermal evaporation seawater desalination water production. Background Art

[0002] Water is fundamental to all sustainable development goals. However, the scarcity of freshwater resources has become a major global concern. A World Water Institute report indicates that approximately a quarter of the world's population faces water shortages. The World Meteorological Organization also stated in its 2021 work report that by 2050, half of the world's population will face water shortages. Therefore, effectively alleviating the freshwater crisis and securing more freshwater resources are urgent issues. Desalination technology offers an effective solution to the freshwater crisis. Current desalination technologies include reverse osmosis, electrodialysis, multi-stage flash evaporation, compressed air, and freezing. However, these technologies generally require large amounts of energy to meet production needs, making them difficult to implement in areas with energy shortages. Furthermore, high costs and complex equipment hinder the further development of these technologies in water-scarce regions, particularly coastal saline-alkali areas and inland salt lake regions.

[0003] Solar energy is an inexhaustible, renewable, clean energy source. Solar interfacial photothermal evaporation technology provides an effective strategy for seawater desalination that is green, environmentally friendly, low-energy, and requires minimal equipment. The core of this technology lies in the construction of photothermal materials with excellent photothermal properties and controllable water absorption properties. Using photothermal materials to achieve photothermal conversion at the water-air interface and accelerate the acquisition of clean water is considered a highly sustainable water resource regeneration technology (Nature Energy 2018, 3(12): 1031-1041). Renowned domestic scholars such as Professors Yu Shuhong, Zhu Meifang, Liu Zhongfan, Zhu Jia, Deng Tao, Xu Zhikang, Qu Liangti, Wang Xun, Wu Ziliang, Chen Zhigang, and Chen Yongsheng have made distinctive contributions to the development of solar interfacial photothermal evaporation systems and their application in seawater desalination.

[0004] Patent CN115403095A discloses a method for preparing a salt-rejecting sponge-based / cheap carbon photothermal composite material, which is characterized in that the material has the effect of resisting salt crystallization, low cost, simple preparation process, etc., but with the increase of salt concentration in the applied water area, the evaporation rate decreases significantly; Patent CN114405421A discloses a method for preparing a cellulose nanofiber aerogel interface photothermal water evaporation material, which is characterized in that the material has high mechanical strength, strong water resistance and stability, low density and self-floating, low thermal conductivity, etc., but most raw materials have the disadvantages of narrow sources, complex preparation process, and high cost. Although a series of important achievements have been made in the construction of photothermal evaporation materials, the serious salt scaling problem has become a key bottleneck restricting its development, not only leading to a decrease in photothermal conversion efficiency, but also causing pore blockage and hindering the water evaporation link in the water regeneration process, thereby affecting the stability and durability of the photothermal evaporation system. In addition, most of the raw materials have narrow sources and a more complicated preparation process, making it difficult to achieve large-scale application. Therefore, whether in the research and development of efficient salt-resistant and stable photothermal materials or in batch preparation, it is urgent to develop a suitable material system to solve the above problems. Summary of the Invention

[0005] The main purpose of the present invention is to provide a novel core-shell super-hydrophobic photothermal material and its preparation method and application, so as to overcome the deficiencies in the prior art.

[0006] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0007] An embodiment of the present invention provides a core-shell super-hydrophobic photothermal material, which includes: activated sea sand as a core, polydopamine as an intermediate layer, and an outer shell layer, wherein the outer shell layer includes a photothermal material and a hydrophobic material.

[0008] In some embodiments, the core-shell superhydrophobic photothermal material has spontaneous aggregation behavior and can form a pore structure with a diameter of 30-180 μm.

[0009] The present invention also provides a method for preparing a core-shell super-hydrophobic photothermal material, which comprises:

[0010] Activating the sea sand to obtain activated sea sand;

[0011] Dopamine hydrochloride is polymerized to modify the surface of the activated sea sand to form polydopamine, thereby obtaining polydopamine sea sand, which is then annealed;

[0012] The annealed polydopamine sea sand, coupling agent and photothermal material monomer are reacted at room temperature to obtain a core-shell superhydrophobic photothermal material.

[0013] The embodiments of the present invention also provide applications of the aforementioned core-shell superhydrophobic photothermal material in the field of seawater desalination.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] 1) The core-shell superhydrophobic photothermal material provided by the present invention has spontaneous agglomeration behavior and can form a large number of pore structures with a diameter of 30-180 μm, which is beneficial to water evaporation during water regeneration. It also has self-floating ability, superhydrophobic properties and photothermal conversion ability, and is an efficient salt-resistant interface photothermal evaporation material;

[0016] 2) In the core-shell super-hydrophobic photothermal material provided by the present invention, there are π-π, π-h, hydrogen bond and other interaction forces between the polydopamine sea sand, the photothermal material and the hydrophobic material, which give the material structural stability; the thermal decomposition temperature of the material is not lower than 325°C, and it has thermal stability; after treatment and friction testing in acidic environment, alkaline environment, chitosan, bovine serum albumin, and humic acid environment, the appearance of the material is not damaged and the original super-hydrophobic properties are still maintained, and it has chemical and physical stability;

[0017] 3) The preparation method provided by the present invention has simple process, low cost, stable performance, and a wide range of raw material acquisition channels. It solves the key scientific problem of the current interfacial photothermal evaporation materials' reduced photothermal conversion capacity due to salt scaling and the problem of limited raw material sources, and provides an effective solution for the continuous and stable acquisition of fresh water by solar interfacial photothermal evaporation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1a 、 Figure 1b 、 Figure 1c The scanning electron microscope images are respectively of the sea sand used in Example 1 of the present invention, the prepared PDSD (i.e., polydopamine sand), and the core-shell superhydrophobic photothermal material (i.e., superhydrophobic photothermal sand);

[0020] Figure 2 Schematic diagram of the super-hydrophobic mechanism of preparing core-shell super-hydrophobic photothermal materials according to the present invention;

[0021] Figure 3 This is a contact angle test diagram of the core-shell superhydrophobic photothermal material prepared in Example 1 of the present invention;

[0022] Figure 4 This is a contact angle test diagram of the comparative material prepared in Comparative Example 1 of the present invention;

[0023] Figure 5 This is the ultraviolet-visible-infrared absorption spectrum of the sea sand used in Example 1 of the present invention and the prepared core-shell super-hydrophobic photothermal material (i.e., super-hydrophobic photothermal sea sand);

[0024] Figure 6 This is a thermal analysis curve of the core-shell superhydrophobic photothermal material prepared in Example 1 of the present invention;

[0025] Figure 7a and Figure 7b This is a graph showing the photothermal water evaporation rate of the core-shell superhydrophobic photothermal material prepared in Example 1 of the present invention;

[0026] Figure 8a and Figure 8b This is a long-term cycle test diagram of the core-shell super-hydrophobic photothermal material prepared in Example 1 of the present invention;

[0027] Figure 9 This is a physical comparison of the salt resistance effect of the core-shell superhydrophobic photothermal material prepared in Example 1 of the present invention and the comparative material prepared in Comparative Example 2;

[0028] Figure 10 This is a physical picture of the core-shell superhydrophobic photothermal material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] In light of the shortcomings of the existing technology, the inventors of this case, after extensive research and extensive practice, have proposed the technical solution of the present invention, providing a method for preparing a core-shell super-hydrophobic photothermal material. This method is primarily prepared through a combination of alkaline activation treatment, step-by-step polymerization, and annealing. This method provides a technical solution to the insufficient salt tolerance of photothermal materials in the field of interfacial photothermal evaporation and seawater desalination. The following further explains this technical solution, its implementation process, and its principles.

[0030] One aspect of an embodiment of the present invention provides a core-shell superhydrophobic photothermal material comprising: activated sea sand (SDs) as a core, polydopamine as an intermediate layer, and an outer shell layer, wherein the outer shell layer comprises a photothermal material and a hydrophobic material.

[0031] In some embodiments, the photothermal material may include any one or a combination of two or more of polypyrrole (Ppy), carbon nanotubes, graphene, graphene oxide, etc., but is not limited thereto.

[0032] In some embodiments, the content of the photothermal material in the core-shell superhydrophobic photothermal material is 25-35 wt %.

[0033] Furthermore, the content of polydopamine in the core-shell superhydrophobic photothermal material is 8-15 wt%.

[0034] In some embodiments, the hydrophobic material includes any one or a combination of two or more of n-octyltrimethoxysilane, hexyltrimethoxysilane, octadecyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTS), etc., preferably 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTS), but is not limited thereto.

[0035] Furthermore, the content of the hydrophobic material in the core-shell super-hydrophobic photothermal material is 0.75-1.75 wt %.

[0036] In summary, the core-shell superhydrophobic photothermal material provided by the present invention has a core-shell structure and is divided into three layers. The core is activated sea sand (SDs), which is the matrix of the material; the middle layer is polydopamine (PDA), which provides stronger binding force for the material; the outer layer is modified with photothermal material (such as polypyrrole Ppy) and hydrophobic material (such as PFDTS), which gives the material photothermal conversion ability and superhydrophobic ability.

[0037] The core-shell superhydrophobic photothermal material (FPPSD) provided by the present invention has the behavior of spontaneous agglomeration and can form a large number of pore structures with a diameter of 30-180 μm, which is beneficial to water evaporation during water regeneration. It also has self-floating ability, superhydrophobic properties and photothermal conversion capabilities, and is an efficient salt-resistant interface photothermal evaporation material.

[0038] Furthermore, compared with traditional photothermal materials, the core-shell superhydrophobic photothermal material of the present invention has π-π, π-h, hydrogen bonds and other interaction forces between photothermal materials such as polydopamine sea sand and polypyrrole and hydrophobic materials, which give the material structural stability; the thermal decomposition temperature of the photothermal material is not lower than 325°C, and it has thermal stability. After treatment and friction testing in acidic environment, alkaline environment, chitosan, bovine serum albumin, and humic acid environment, the appearance of the photothermal material is not damaged and the original superhydrophobic properties are still maintained, and it has chemical and physical stability.

[0039] Furthermore, compared with traditional photothermal materials, the core-shell superhydrophobic photothermal material of the present invention has superhydrophobic properties, a contact angle of not less than 150°, and can continuously evaporate in simulated high-salinity seawater (10%) for 8-12 hours under an illumination intensity of 3 suns, maintaining stable evaporation; the same results were obtained in a continuous 8-10 day cycle test.

[0040] Another aspect of the embodiments of the present invention further provides a method for preparing a core-shell super-hydrophobic photothermal material, comprising:

[0041] Activating the sea sand to obtain activated sea sand;

[0042] Dopamine hydrochloride is polymerized to modify the surface of the activated sea sand to form polydopamine, thereby obtaining polydopamine sea sand, which is then annealed;

[0043] The annealed polydopamine sea sand, coupling agent and photothermal material monomer are reacted at room temperature to obtain a core-shell superhydrophobic photothermal material.

[0044] In a specific embodiment, the preparation method includes: activating sea sand with an alkaline substance to obtain activated sea sand.

[0045] Furthermore, the preparation method specifically includes: mixing sea sand with an alkaline solution, and treating the mixture in an ultrasonic environment to obtain activated sea sand.

[0046] In a specific embodiment, the preparation method includes: stirring and mixing annealed polydopamine sea sand, a coupling agent and a photothermal material monomer, and adding an oxidant solution to complete the stirring reaction at room temperature to obtain a core-shell superhydrophobic photothermal material.

[0047] In some embodiments, the photothermal material monomer may include any one or a combination of two or more of pyrrole (PPy), carbon nanotubes, graphene, graphene oxide, etc., but is not limited thereto.

[0048] In some embodiments, the coupling agent includes any one or a combination of two or more of n-octyltrimethoxysilane, hexyltrimethoxysilane, octadecyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTS), and the like, preferably 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTS), but is not limited thereto. The coupling agent used in the present invention undergoes a hydrolysis reaction and polymerization to form a hydrophobic polymer (i.e., the aforementioned hydrophobic material).

[0049] In addition, the present invention adds an oxidant to participate in the oxidative polymerization of the photothermal material (such as pyrrole); at the same time, an acidic environment is provided for the hydrolysis of the coupling agent. Figure 2 As shown in the figure, different photothermal materials have different loading and polymerization methods. For example, when an oxidant is involved in the reaction, pyrrole bonds to the material matrix through oxidative polymerization. Carbon nanotubes, graphene oxide, and graphene are mostly deposited on the matrix through solution mixing, ultrasonic mixing, and then the solvent is removed, resulting in weak interaction.

[0050] In a more specific embodiment, the core-shell superhydrophobic photothermal material is prepared by combining alkali activation treatment, stepwise polymerization and annealing treatment, and the preparation method specifically comprises the following steps:

[0051] (1) Pretreatment (i.e., alkaline activation treatment): prepare an alkaline solution of a certain concentration and place it in an ultrasonic environment, and mix it thoroughly to obtain solution A; mix the sea sand (SDs) washed with anhydrous ethanol with solution A, activate it with an alkaline solution, and place it in an ultrasonic environment for treatment; after the treatment is completed, rinse it to neutrality and dry it to obtain activated sea sand; use a buffer and deionized water to prepare an alkaline buffer solution of a certain pH value, place it on a stirrer and stir it thoroughly to obtain alkaline buffer solution B;

[0052] (2) Dopamine modification and annealing: The activated sea sand obtained in step (1), alkaline buffer B and dopamine hydrochloride are mixed in different proportions, placed on a stirrer and stirred evenly, and oxidative self-polymerization is completed in an alkaline buffer solution environment. After the polymerization reaction is heated and stirred, the product is rinsed to neutrality and annealed to obtain PDSD (polydopamine sea sand);

[0053] (3) Functionalization of photothermal components: The PDSD, coupling agent, pyrrole and other photothermal materials obtained in step (2) are mixed in different proportions, placed on a stirring table for mixing, and the solid components are retained. An oxidant solution is added to complete the stirring reaction at room temperature to obtain a core-shell superhydrophobic photothermal material (FPPSD).

[0054] In some preferred embodiments, in step (1), the raw material sea sand is ordinary commercial sea sand, and the alkaline solution (i.e., solution A) includes a sodium hydroxide (NaOH) solution with a concentration of 0.5-1 mol·L -1 .

[0055] Furthermore, the buffer is tris (hydroxymethyl)aminomethane (Tris), and the alkaline buffer B is a Tris buffer solution, and its pH value is adjusted to 7-10 using a hydrochloric acid solution.

[0056] In some preferred embodiments, in step (2), the mass of dopamine hydrochloride added to the alkaline buffer solution is 1‰-3‰ (mass ratio to Tris buffer solution).

[0057] In some preferred embodiments, the polymerization reaction temperature is 30-50° C., and the polymerization reaction time is 10-16 h.

[0058] In some preferred embodiments, the annealing treatment temperature is 70-100° C., the holding time is 6-16 hours, and the material is cooled naturally. The present invention can reduce the residual stress of the material, stabilize the size, and reduce the tendency of deformation and cracking through annealing.

[0059] In some preferred embodiments, in step (3), the mass ratio of the photothermal material monomer to the polydopamine sea sand is 1:1-5:1. For example, the amount of PDSD used is 5g, and the amount of the photothermal material monomer (such as pyrrole) used is twice the mass of the polydopamine sea sand (10g).

[0060] Furthermore, the added amount of the coupling agent is 2%-5% of the mass of the photothermal material monomer (such as pyrrole); and the stirring and mixing time is 20-30 minutes.

[0061] Furthermore, the oxidant solution includes a ferric chloride solution (such as FeCl3·6H2O solution) with a concentration of 0.1-1 mol·L -1 The reaction time is 4-12h and the temperature is room temperature.

[0062] Specifically, the reaction carried out in step (3) includes: oxidative polymerization reaction of the photothermal material, hydrolysis and polymerization reaction of the coupling agent, and dehydration condensation reaction of the coupling agent and polydopamine after polymerization, which also involves some interaction forces, such as π-π, π-H, H bonds, etc.

[0063] In summary, the preparation method of the present invention has a simple process, low cost, a wide range of raw material acquisition channels, stable performance, excellent salt resistance and corrosion resistance, and is suitable for large-area applications. The prepared core-shell superhydrophobic photothermal material solves the key scientific problem of the current interface photothermal evaporation material's reduced photothermal conversion capacity due to salt scaling and the application problem of narrow raw material sources, providing an effective solution for continuous and stable solar interface photothermal evaporation to obtain fresh water.

[0064] Another aspect of the embodiments of the present invention further provides a core-shell superhydrophobic photothermal material prepared by the aforementioned preparation method.

[0065] Another aspect of the embodiments of the present invention further provides the application of the core-shell superhydrophobic photothermal material in the field of seawater desalination.

[0066] In order to make the purpose, technical solution and explanation of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the present invention. The following is a detailed description through specific examples.

[0067] Example 1

[0068] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol.L -1The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0069] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was continuously stirred at 40°C for 14 h to undergo polymerization. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then repeatedly washed with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0070] (3) Functionalization of photothermal components: PDSD (5 g), pyrrole (10 g), and 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken, shaken for 30 min, and then separated. The precipitate was retained and added with 0.5 M FeCl3·6H2O solution (10 ml). The reaction was stirred at room temperature for 6 h, and then separated, rinsed, and dried to obtain the core-shell superhydrophobic photothermal material FPPSD.

[0071] The inventors of this case also characterized the core-shell super-hydrophobic photothermal material FPPSD prepared in this embodiment, and specifically tested the morphology, photothermal conversion performance and evaporation performance of the obtained FPPSD. The scanning electron microscope images of the sea sand used in this embodiment, the prepared PDSD (i.e., polydopamine sand), and the core-shell super-hydrophobic photothermal material (i.e., super-hydrophobic photothermal sand) are shown as follows: Figure 1a 、 Figure 1b 、 Figure 1c The schematic diagram of super hydrophobic mechanism is shown in Figure 2 The obtained FPPSD can spontaneously aggregate to form a pore structure with a contact angle with water greater than 150° (as shown in FIG. Figure 3 The UV-visible-infrared absorption spectrum of the obtained FPPSD is shown in FIG. Figure 5 As shown in the thermal analysis curve Figure 6 As shown. The solar absorption rate is 91%. In a dark environment, the evaporation of water is low, at 0.05kg.m -2 ·h -1 In a sunlight environment, the evaporation rate reaches 1.08 kg·m -2 ·h -1 (like Figure 7a and Figure 7bThe evaporation rate remained stable (3 kg·m -2 ·h -1 ), there was no salt deposition on the surface of the material, and it remained stable during the subsequent 10-day cycle experiment (e.g. Figure 8a 、 Figure 8b 、 Figure 9 shown). Figure 10 This is a physical picture of the core-shell superhydrophobic photothermal material prepared in this example.

[0072] Example 2 (dopamine hydrochloride polymerization reaction conditions, 30°C / 16h)

[0073] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0074] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was stirred at 30°C for 16 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0075] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The mixture was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0076] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. The solar light absorption rate of the intermediate product and FPPSD fluctuated, the wettability fluctuated, and the contact angle was still greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0077] Example 3 (dopamine hydrochloride polymerization reaction conditions, 50°C / 10h)

[0078] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0079] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was stirred at 50°C for 10 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0080] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The mixture was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0081] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. The solar light absorption rate did not change significantly, and the wettability fluctuated, but the contact angle was still greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0082] Example 4 (annealing conditions, 70°C / 16h)

[0083] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0084] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was stirred at 40°C for 14 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 70°C for 16 h and allowed to cool naturally to complete annealing.

[0085] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The mixture was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0086] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. The irregularity of the morphology of the intermediate product and FPPSD increased, the solar light absorption rate fluctuated, and the wettability fluctuated, but the contact angle was still greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0087] Example 5 (annealing conditions, 100°C / 6h)

[0088] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0089] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was stirred at 40°C for 16 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 100°C for 6 h and allowed to cool naturally to complete annealing.

[0090] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The mixture was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0091] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. The solar light absorption capacity and wettability did not change significantly, meeting the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0092] Example 6 (Oxidation reaction conditions, oxidant solution concentration 0.1 M / reaction 12 h)

[0093] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, washed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 7 with 0.1 M HCl. Subsequently, the volume of the resulting Tris solution was adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0094] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was stirred at 40°C for 14 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0095] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.1 M FeCl3·6H2O solution (10 ml) was added. The mixture was stirred at room temperature for 12 h, and FPPSD was obtained after separation, washing, and drying.

[0096] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. The solar light absorption capacity and wettability did not change significantly, meeting the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0097] Example 7 (Oxidation reaction conditions, oxidant solution concentration 1M / reaction 4h)

[0098] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L- 1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, washed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 10 with 0.1 M HCl. Subsequently, the volume of the resulting Tris solution was adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0099] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was stirred at 40°C for 14 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0100] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 20 min before separation. The precipitate was retained and 1 M FeCl3·6H2O solution (10 ml) was added. The mixture was stirred at room temperature for 4 h, and FPPSD was obtained after separation, washing, and drying.

[0101] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. The surface color of the material changed, and the sunlight absorption capacity and wettability fluctuated, but it still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0102] Example 8 (dopamine hydrochloride dosage 1‰)

[0103] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0104] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.015 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (1‰). Activated sea sand (5 g) was added and the mixture was stirred at 40°C for 14 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0105] (3) Photothermal component functionalization: PDSD (10 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The mixture was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0106] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. The surface color of the intermediate product material changed, and the sunlight absorption capacity and wettability fluctuated, but it still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0107] Example 9 (dopamine hydrochloride dosage 3‰)

[0108] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0109] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.045 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (3‰). Activated sea sand (5 g) was added and the mixture was stirred at 40°C for 14 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0110] (3) Photothermal component functionalization: PDSD (2 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The mixture was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0111] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. The solar light absorption capacity and wettability did not change significantly, meeting the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0112] Example 10 (coupling agent dosage 5%)

[0113] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0114] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was continuously stirred at 40°C for 14 h for polymerization. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). Subsequently, the PDSD was repeatedly washed with deionized water until neutral, then maintained at 90°C for 12 h and naturally cooled to complete annealing.

[0115] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.5 g) [5%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0116] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. Its color became lighter, the contact angle increased, the salt resistance was enhanced, and the solar light absorption rate and water evaporation rate fluctuated, but it still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0117] Example 11 (coupling agent dosage 3%)

[0118] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0119] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was continuously stirred at 40°C for 14 h to undergo polymerization. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then repeatedly washed with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0120] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.3 g) [3%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0121] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. Its wettability fluctuated, but the contact angle was greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0122] Example 12 (coupling agent is octadecanetrimethoxysilane)

[0123] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0124] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was continuously stirred at 40°C for 14 h to undergo polymerization. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then repeatedly washed with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0125] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and octadecyltrimethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0126] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. Its wettability fluctuated, but the contact angle was greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0127] Example 13 (coupling agent is n-octyltrimethoxysilane)

[0128] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 1 mol.L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0129] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was continuously stirred at 40°C for 14 h to undergo polymerization. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then repeatedly washed with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0130] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and n-octyltrimethoxysilane (0.5 g) [5%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0131] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. Its wettability fluctuated, but the contact angle was greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0132] Example 14 (coupling agent is hexyltrimethoxysilane)

[0133] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.8 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0134] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was continuously stirred at 40°C for 14 h to undergo polymerization. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then repeatedly washed with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0135] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and hexyltrimethoxysilane (0.5 g) [5%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0136] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. Its wettability fluctuated, but the contact angle was greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0137] Example 15 (photothermal material is carbon nanotubes)

[0138] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.7 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0139] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was continuously stirred at 40°C for 14 h to undergo polymerization. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then repeatedly washed with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0140] (3) Photothermal component functionalization: PDSD (5 g), carbon nanotubes (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.2 g) [2%] were taken and shaken for 25 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and then dried, rinsed, and dried to obtain FPPSD.

[0141] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. Its photothermal conversion ability fluctuated, and the contact angle was greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0142] Example 16 (photothermal material is graphene)

[0143] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.9 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0144] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was continuously stirred at 40°C for 14 h to undergo polymerization. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then repeatedly washed with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0145] (3) Photothermal component functionalization: PDSD (5 g), graphene (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 25 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and then dried, rinsed, and dried to obtain FPPSD.

[0146] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. Its photothermal conversion ability fluctuated, and the contact angle was greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0147] Example 16 (photothermal material is graphene oxide)

[0148] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.6 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0149] (2) Dopamine modification and annealing: Add dopamine hydrochloride (0.03 g) to Tris solution (15 ml), stir evenly to obtain dopamine / Tris solution (2‰), add activated sea sand (5 g) and continuously stir the mixture at 40°C for 14 hours to polymerize. Dopamine monomers are in situ polymerized on the surface of the sea sand to obtain PDSD (PDSD). Afterwards, the PDSD is repeatedly washed with deionized water until neutral, and then kept at 90°C for 12 hours, and naturally cooled to complete annealing. Photothermal conversion ability

[0150] (3) Photothermal component functionalization: PDSD (5 g), graphene oxide (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 25 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and then dried, rinsed, and dried to obtain FPPSD.

[0151] The inventors of this case also characterized the core-shell superhydrophobic photothermal material FPPSD prepared in this embodiment. Its photothermal conversion ability fluctuated, and the contact angle was greater than 150°, which still met the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0152] Comparative Example 1 (no annealing step)

[0153] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, then rinsed with deionized water until neutral and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0154] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was stirred at 40°C for 14 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). PDSD was then washed repeatedly with deionized water until neutral.

[0155] (3) Photothermal component functionalization: PDSD (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.5 g) [5%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and FPPSD was obtained after separation, washing, and drying.

[0156] The inventors of this case also characterized the photothermal material obtained in this comparative example. The particle size was uneven and the diffuse scattering phenomenon was serious. The contact angle test results were as follows: Figure 4 As shown, the sunlight absorption capacity decreases, the photothermal conversion capacity decreases, and it cannot meet the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0157] Comparative Example 2 (no coupling agent added, high evaporation rate, poor salt resistance)

[0158] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The surface was roughened by ultrasonic treatment in a NaOH solution for 2 h, rinsed with deionized water until neutral, and dried. Tris (6.07 g) was added to deionized water (500 ml) under magnetic stirring, and the pH of the resulting solution was adjusted to 8.5 with 0.1 M HCl. The volume of the resulting Tris solution was then adjusted to 1000 ml with deionized water to obtain a Tris buffer solution.

[0159] (2) Dopamine modification and annealing: Dopamine hydrochloride (0.03 g) was added to a Tris solution (15 ml) and stirred to obtain a dopamine / Tris solution (2‰). Activated sea sand (5 g) was added and the mixture was stirred at 40°C for 14 h. Dopamine monomers were in situ polymerized on the sea sand surface to obtain PDSD (PDSD). The PDSD was then washed repeatedly with deionized water until neutral, then maintained at 90°C for 12 h and allowed to cool naturally to complete annealing.

[0160] (3) Photothermal component functionalization: PDSD (5 g) and pyrrole (10 g) were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h. PPSD was then separated, rinsed, and dried to obtain PPSD.

[0161] After testing, the photothermal material PPSD obtained in this comparative example produced a large amount of salt crystal particles (such as Figure 9 As shown), it cannot meet the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0162] Comparative Example 3 (no dopamine hydrochloride added, poor recyclability of the material)

[0163] (1) Pretreatment: First, the sea sand was carefully cleaned with deionized water and anhydrous ethanol for 30 min under ultrasonic conditions and dried; the clean sea sand was placed in 0.5 mol·L -1 The rough surface was obtained by ultrasonic treatment in NaOH solution for 2 h, washed with deionized water to neutrality, and dried.

[0164] (2) Photothermal component functionalization: SDs (5 g), pyrrole (10 g), and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (0.4 g) [4%] were taken and shaken for 30 min before separation. The precipitate was retained and 0.5 M FeCl3·6H2O solution (10 ml) was added. The reaction was stirred at room temperature for 6 h, and FPSD was obtained after separation, washing, and drying.

[0165] After testing, the photothermal material FPSD obtained in this comparative example has poor cyclability and cannot meet the requirements of long-term and efficient interfacial photothermal evaporation for seawater desalination.

[0166] In summary, the preparation method of the core-shell super-hydrophobic photothermal material provided by the present invention is completed by alkali activation treatment of sea sand and surface modification of functional groups. Sea sand provides the matrix of the material; the middle layer of polydopamine mainly provides a more solid binding method for the material; the outer layer of photothermal material and the coupling agent provide the material with photothermal conversion ability and salt resistance, respectively. The super-hydrophobic photothermal sand obtained by the present invention has spontaneous agglomeration behavior, can form a pore structure, has self-floating ability, super-hydrophobic characteristics and photothermal conversion ability, and is a highly efficient and salt-resistant interface photothermal evaporation material. It avoids the key application problem of the degradation of photothermal conversion performance due to salt scaling during long-term operation in interface photothermal evaporation, and provides an effective and feasible solution for obtaining fresh water by solar interface photothermal evaporation; and the preparation method is simple, and the salt resistance and corrosion resistance are excellent, making it suitable for large-scale application.

[0167] The inventors also used other raw materials and process conditions listed in this specification, and in accordance with the methods of the aforementioned examples, to produce a series of core-shell superhydrophobic photothermal materials. Testing revealed that these core-shell superhydrophobic photothermal materials also exhibit the excellent properties described in this specification.

[0168] The above description of the embodiments is intended to facilitate understanding and application of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a core-shell super-hydrophobic photothermal material, characterized in that: include: Activating sea sand with alkaline substances to obtain activated sea sand; Activated sea sand, alkaline buffer and dopamine hydrochloride are mixed and heated and stirred to perform a polymerization reaction, thereby modifying the surface of the activated sea sand to form polydopamine to obtain polydopamine sea sand, and the product is rinsed to neutrality and annealed; the polymerization reaction temperature is 30-50° C., the polymerization reaction time is 10-16 hours; the annealing temperature is 70-100° C., and the time is 6-16 hours; The annealed polydopamine sea sand, a coupling agent and a photothermal material monomer are stirred and mixed, and an oxidant solution is added to complete the stirring reaction at room temperature to obtain a core-shell superhydrophobic photothermal material, wherein the coupling agent is a hydrophobic material selected from any one of n-octyltrimethoxysilane, hexyltrimethoxysilane, octadecanetrimethoxysilane, and 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane or a combination of two or more thereof.

2. The preparation method according to claim 1, wherein: The alkaline substance is an alkaline solution. The sea sand is mixed with the alkaline solution and treated in an ultrasonic environment to obtain activated sea sand.

3. The preparation method according to claim 2, characterized in that include: The alkaline solution is a sodium hydroxide solution with a concentration of 0.5-1 mol·L -1 .

4. The preparation method according to claim 1, wherein: The alkaline buffer solution is a tris(hydroxymethyl)aminomethane buffer solution with a pH value of 7-10.

5. The preparation method according to claim 1, wherein: The added mass of the dopamine hydrochloride in the alkaline buffer solution is 1‰-3‰.

6. The preparation method according to claim 1, wherein: The photothermal material monomer is selected from any one or a combination of two or more of pyrrole, carbon nanotubes, graphene, and graphene oxide.

7. The preparation method according to claim 1, wherein: The mass ratio of the photothermal material monomer to the polydopamine sea sand is 1:1-5:

1.

8. The preparation method according to claim 1, wherein: The coupling agent is 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane.

9. The preparation method according to claim 1, wherein: The added amount of the coupling agent is 2%-5% of the mass of the photothermal material monomer.

10. The preparation method according to claim 1, characterized in that: The stirring and mixing time is 20-30 minutes.

11. The preparation method according to claim 1, characterized in that: The oxidant solution is a ferric chloride solution with a concentration of 0.1-1 mol·L -1 The reaction time is 4-12h.

12. A core-shell super-hydrophobic photothermal material prepared by the preparation method according to any one of claims 1 to 11, characterized in that: include: Activated sea sand as a core, polydopamine as a middle layer, and an outer shell layer, wherein the outer shell layer includes a photothermal material and a hydrophobic material.

13. The core-shell super-hydrophobic photothermal material according to claim 12, characterized in that: The content of the photothermal material in the core-shell super-hydrophobic photothermal material is 25-35 wt %.

14. The core-shell super-hydrophobic photothermal material according to claim 12, characterized in that: The content of polydopamine in the core-shell superhydrophobic photothermal material is 8-15 wt %.

15. The core-shell super-hydrophobic photothermal material according to claim 12, characterized in that: The content of the hydrophobic material in the core-shell super-hydrophobic photothermal material is 0.75-1.75 wt %.

16. The core-shell super-hydrophobic photothermal material according to claim 12, characterized in that: The core-shell super-hydrophobic photothermal material has spontaneous agglomeration behavior and can form a pore structure with a diameter of 30-180 μm.

17. The core-shell super-hydrophobic photothermal material according to claim 12, characterized in that: The thickness of the intermediate layer is 30-100 nm.

18. The core-shell super-hydrophobic photothermal material according to claim 12, characterized in that: The thickness of the outer shell layer is 50-200 nm.

19. The core-shell super-hydrophobic photothermal material according to claim 12, characterized in that: The thermal decomposition temperature of the core-shell super-hydrophobic photothermal material is not lower than 325°C.

20. The core-shell super-hydrophobic photothermal material according to claim 12, characterized in that: The core-shell superhydrophobic photothermal material has a contact angle of no less than 150° and can evaporate continuously in 10% salinity seawater for 8-12 hours under an illumination intensity of 3 suns, maintaining stable evaporation for 8-10 consecutive days.

21. Use of the core-shell superhydrophobic photothermal material according to any one of claims 12 to 20 in the field of seawater desalination.

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