A method for preparing a hydrophobic photo-thermal sponge material for oil spill recovery

Abstract

This invention discloses a method for preparing a hydrophobic photothermal sponge material for oil spill recovery. The method involves first in-situ self-polymerization of dopamine on the surface of a melamine sponge to form a polydopamine-coated melamine sponge. Then, the sponge is immersed in a prepolymer solution made of methacrylate-functionalized polydimethylsiloxane, a crosslinking agent, and silica nanoparticles. After sufficient adsorption, the solution is heated and cured, causing chemical crosslinking of the prepolymer on the polydopamine layer surface. This constructs an organic-inorganic hybrid hydrophobic coating with a micro-nano composite structure, thereby obtaining the hydrophobic photothermal sponge material. This invention features a simple preparation process, inexpensive and readily available raw materials, and the resulting material exhibits high adsorption efficiency for high-viscosity crude oil at 1 kW·m⁻¹. ‑2 Under simulated sunlight, its complete adsorption time for high-viscosity crude oil is shortened to 60 seconds, achieving an adsorption rate increase of more than 24 times compared to the original sponge, making it extremely valuable for marine oil spill recovery.

Description

Technical Field

[0001] This invention belongs to the field of coating materials technology, specifically relating to a method for preparing a hydrophobic photothermal sponge material for oil spill recovery. Background Technology

[0002] Petroleum, as an indispensable fossil fuel in modern society, plays a vital role in industrial production and daily life. However, in recent decades, with the rapid development of global industrialization, offshore oil exploration and transportation activities have become increasingly frequent, leading to frequent oil spills and placing increasing pressure on the marine environment. To address the problem of oil slicks on the sea surface, researchers have proposed various treatment technologies, such as mechanical skimming, chemical dissipation, or controlled on-site combustion. However, these methods each have their inherent drawbacks, such as high cost, low efficiency, and the potential for secondary pollution. Therefore, developing efficient, economical, and environmentally friendly oil spill treatment technologies has become a current research hotspot.

[0003] In recent years, various functional oil-absorbing materials have been developed, including specialized fabrics, metal meshes, aerogels, and sponges. Among them, low-cost, highly elastic three-dimensional porous sponge materials, especially melamine sponges, have attracted widespread attention in the field of oil spill recovery due to their excellent oleophilic-hydrophobic properties (i.e., oil-water selectivity) and high adsorption capacity. Commercially available melamine sponges possess high porosity, excellent elasticity, and significant adsorption potential. However, their inherent amphiphilicity—the ability to simultaneously absorb water and oil phases—poses a significant obstacle to selective oil recovery at sea. Therefore, this invention modifies melamine sponges to transform them into superhydrophobic materials that preferentially attract oil while repelling water. Summary of the Invention

[0004] To address the problems of low adsorption weight, poor oil spill recovery performance, and insufficient chemical stability of traditional oil spill recovery sponges, this invention provides a method for preparing a hydrophobic photothermal sponge material for oil spill recovery. The prepared photothermal hydrophobic sponge has good mechanical stability and excellent chemical stability, and can achieve rapid adsorption of high-viscosity crude oil.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a hydrophobic photothermal sponge material for oil spill recovery, comprising the following steps: (1) Immerse the melamine sponge in a dopamine solution to allow the dopamine to undergo a self-polymerization reaction, thereby forming a polydopamine coating on the surface of the melamine sponge. Then remove and dry it to obtain a polydopamine-coated melamine sponge. (2) The methacrylate-functionalized polydimethylsiloxane, crosslinking agent, and silica nanoparticles are dispersed in an organic solvent and mixed uniformly by ultrasonication to form a prepolymer solution; (3) The polydopamine-coated melamine sponge obtained in step (1) is immersed in the prepolymer solution in step (2) so that the prepolymer is fully adsorbed into the sponge. Then it is taken out and heated to cure, thereby constructing a micro-nano composite hydrophobic coating containing silica nanoparticles on the surface of the polydopamine coating through a chemical cross-linking reaction, so as to obtain the hydrophobic photothermal sponge material.

[0006] Further, the melamine sponge used in step (1) has a length of 15~25 μm, a width of 15~25 μm, and a thickness of 8~15 mm. Preferably, the melamine sponge has a length of 20 μm and a thickness of 10 mm.

[0007] Furthermore, the mass concentration of the dopamine solution used in step (1) is 2~2.5 g / L.

[0008] Furthermore, the temperature of the self-polymerization reaction in step (1) is 25°C and the time is 10h.

[0009] Further, the methacrylate-functionalized polydimethylsiloxane described in step (2) is prepared by mixing hydroxyl-terminated polydimethylsiloxane, 3-(methacryloyloxy)propyltrimethoxysilane (KH-570), dibutyltin dilaurate, and deionized water, stirring the mixture at room temperature for 12 hours, and then distilling the reaction mixture under reduced pressure at 60°C for 2 hours to remove residual water and unreacted small molecules, thereby obtaining a colorless and transparent target product.

[0010] Furthermore, the mass ratio of hydroxyl-terminated polydimethylsiloxane, KH-570, dibutyltin dilaurate, and deionized water used is 100:15:0.5:1.

[0011] Further, the crosslinking agent mentioned in step (2) is ethylene glycol dimethacrylate.

[0012] Furthermore, the mass ratio of methacrylate-functionalized polydimethylsiloxane, crosslinking agent, and silica nanoparticles used in step (2) is 70:10:3.5.

[0013] Further, the organic solvent mentioned in step (2) is one or more of N,N-dimethylformamide, dimethyl sulfoxide, and n-hexane.

[0014] Furthermore, the ultrasound time in step (2) is 5 to 30 minutes, preferably 20 minutes.

[0015] Furthermore, the mass concentration of the prepolymer solution obtained in step (2) is 150~175 g / L.

[0016] Furthermore, in step (3), the immersion time of the polydopamine-coated melamine sponge in the prepolymer solution is 1~20 min, preferably 5~10 min.

[0017] Further, the heating and curing temperature in step (3) is 60~100 ℃, and the time is 1~10 h. Preferably, the curing temperature is 80 ℃, and the time is 4 h.

[0018] The hydrophobic photothermal sponge material of this invention can achieve a dual synergistic mechanism of photothermal viscosity reduction and interface driving: under light irradiation, the material heats up rapidly, which drastically reduces the viscosity of high-viscosity crude oil, and the super-oleophilic interface simultaneously and significantly enhances the capillary penetration driving force. The two work together to significantly accelerate the crude oil adsorption rate.

[0019] The significant advantages of this invention are: This invention constructs an intermediate layer on the surface of melamine sponge through the self-polymerization of polydopamine, which combines efficient photothermal conversion with strong interfacial adhesion. This intermediate layer is then immersed in a prepolymer solution composed of methacrylate-functionalized polydimethylsiloxane, a crosslinking agent, and silica nanoparticles. Heating and curing achieve in-situ chemical crosslinking and organic-inorganic hybridization, thereby constructing a stable micro / nano composite rough hydrophobic coating on the sponge skeleton. Polydopamine, as the core of photothermal conversion, efficiently converts solar energy into thermal energy due to its broad-spectrum absorption and π-π conjugated structure. The micro / nano rough structure creates a light trapping effect, further enhancing light absorption and photothermal output. Simultaneously, the silane network and low surface energy polymer endow the material with superhydrophobic and superoleophilic properties. Therefore, this invention, through the integrated design of a polydopamine bifunctional intermediate layer, organic-inorganic micro / nano hybridization, and photothermal-interfacial synergy, achieves a comprehensive improvement in adsorption rate, adsorption capacity, structural stability, and engineering practicality, providing an original integrated solution for high-viscosity crude oil recovery.

[0020] Tests showed that at 1 kW·m 2 Under simulated sunlight, the hydrophobic photothermal sponge reduces the complete adsorption time of high-viscosity crude oil to 60 seconds, with a water contact angle of approximately 146°. It also exhibits excellent mechanical and chemical stability, enabling 500 compression-release cycles. This allows for efficient, continuous, and environmentally friendly recycling of high-viscosity marine crude oil. Attached Figure Description

[0021] Figure 1 The image shows the infrared characterization of the methacrylate-functionalized polydimethylsiloxane used in this invention.

[0022] Figure 2 Scanning electron microscope (SEM) images of the polydopamine-coated melamine sponge, hydrophobic photothermal sponge material prepared in the examples, and the hydrophobic photothermal sponge material prepared in Comparative Example 3.

[0023] Figure 3 The images show the surface wettability of the polydopamine-coated melamine sponge, hydrophobic photothermal sponge material prepared in the examples, and the hydrophobic photothermal sponge material prepared in Comparative Example 3.

[0024] Figure 4 The UV-Vis-NIR spectra of the polydopamine-coated melamine sponge and the hydrophobic photothermal sponge material prepared for the examples are shown.

[0025] Figure 5 The polydopamine-coated melamine sponge, hydrophobic photothermal sponge material prepared for the examples, and the hydrophobic photothermal sponge material prepared for Comparative Example 3 were tested at 1.0 kW / m². 2 The graph shows the change in photothermal conversion performance over time under simulated illumination.

[0026] Figure 6 The hydrophobic photothermal sponge material prepared for the example achieved a power output of 0.5 kW / m². 2 1.0 kW / m 2 1.5 kW / m 2 2.0kW / m 2 A graph showing the changes in photothermal conversion performance under simulated illumination.

[0027] Figure 7 The hydrophobic photothermal sponge material prepared for the example achieved a power output of 1.0 kW / m². 2 The graph shows the photothermal conversion performance after 10 cycles of simulated illumination.

[0028] Figure 8 The hydrophobic photothermal sponge material prepared for this example operates in the dark and at 1.0 kW / m². 2 Comparison of crude oil adsorption under simulated light.

[0029] Figure 9 The compression-release cycle performance of the polydopamine-coated melamine sponge, hydrophobic photothermal sponge material prepared in the examples, and the hydrophobic photothermal sponge material prepared in Comparative Example 3 are shown.

[0030] Figure 10 The water contact angle changes of the hydrophobic photothermal sponge materials prepared in Examples and Comparative Example 3 after immersion in artificial seawater of different pH values ​​for 7 days. Detailed Implementation

[0031] A method for preparing a hydrophobic photothermal sponge material for oil spill recovery, comprising the following steps: (1) Immerse the melamine sponge in a dopamine solution with a mass concentration of 2~2.5 g / L, and let the dopamine self-polymerize on the surface of the melamine sponge at 25°C for 10 h. Then take it out and dry it to obtain polydopamine-coated melamine sponge. (2) The methacrylate-functionalized polydimethylsiloxane, the crosslinking agent ethylene glycol dimethacrylate, and the silica nanoparticles are dispersed in an organic solvent at a mass ratio of 70:10:3.5 and ultrasonically treated for 5~30 min to form a prepolymer solution with a concentration of 150~175 g / L. (3) The polydopamine-coated melamine sponge obtained in step (1) is immersed in the prepolymer solution in step (2) for 1 to 20 min to allow the prepolymer to be fully adsorbed into the sponge. Then it is taken out and heated and cured at 60 to 100 °C for 1 to 10 h to obtain the hydrophobic photothermal sponge material.

[0032] The organic solvent mentioned in step (2) is one or more of N,N-dimethylformamide, dimethyl sulfoxide, and n-hexane.

[0033] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0034] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0035] The methacrylate-functionalized polydimethylsiloxane used in the examples was prepared by mixing 100 parts by weight of hydroxyl-terminated polydimethylsiloxane, 15 parts by weight of 3-(methacryloyloxy)propyltrimethoxysilane (KH-570), 0.5 parts by weight of dibutyltin dilaurate, and 1 part by weight of deionized water, stirring the mixture at room temperature for 12 hours, and then distilling the reaction mixture under reduced pressure at 60°C for 2 hours to remove residual water and unreacted small molecules, yielding a colorless and transparent target product.

[0036] Figure 1 Infrared characterization of the prepared methacrylate-functionalized polydimethylsiloxane. As can be seen from the figure, compared to OH-PDMS, it exhibits better performance at 1723 cm⁻¹. -1 The characteristic peak at 1640 cm⁻¹ is attributed to the C=O stretching vibration. -1 The presence of C=C characteristic peaks confirms the successful synthesis of methacrylate-functionalized polydimethylsiloxane. Example

[0037] First, 5 parts by weight of dopamine hydrochloride, 5 parts by weight of tris(hydroxymethyl)aminomethane hydrochloride, and 1.6 parts by weight of potassium hydroxide were dissolved in 500 parts by weight of water and stirred thoroughly (stirring speed 500 rpm, stirring time 24 h) to obtain a polydopamine solution. Melamine sponge was then soaked in this polydopamine solution for 24 h and vacuum dried at 60 ℃ for 6 h to obtain polydopamine-coated melamine sponge.

[0038] 1.4 parts by weight of methacrylate-functionalized polydimethylsiloxane, 0.2 parts by weight of ethylene glycol dimethacrylate, and 0.07 parts by weight of silica nanoparticles were dispersed in 40 parts by weight of n-hexane and ultrasonically treated for 30 min to form a prepolymer solution. A pre-prepared polydopamine-coated melamine sponge was immersed in this prepolymer solution, removed after 10 min, and cured and dried at 80°C for 10 h to obtain the target sponge material.

[0039] Comparative Example 1 First, 5 parts by weight of dopamine hydrochloride, 5 parts by weight of tris(hydroxymethyl)aminomethane hydrochloride, and 1.6 parts by weight of potassium hydroxide were dissolved in 500 parts by weight of water and stirred thoroughly (stirring speed 500 rpm, stirring time 24 h) to obtain a polydopamine solution. Melamine sponge was then soaked in this polydopamine solution for 24 h and vacuum dried at 60 ℃ for 6 h to obtain polydopamine-coated melamine sponge.

[0040] 1.4 parts by weight of methacrylate-functionalized polydimethylsiloxane were dispersed in 40 parts by weight of n-hexane and ultrasonically treated for 30 min to form a prepolymer solution. A pre-prepared polydopamine-coated melamine sponge was immersed in this prepolymer solution, removed after 10 min, and cured and dried at 80°C for 10 h to obtain the target sponge material.

[0041] Comparative Example 2 First, 5 parts by weight of dopamine hydrochloride, 5 parts by weight of tris(hydroxymethyl)aminomethane hydrochloride, and 1.6 parts by weight of potassium hydroxide were dissolved in 500 parts by weight of water and stirred thoroughly (stirring speed 500 rpm, stirring time 24 h) to obtain a polydopamine solution. Melamine sponge was then soaked in this polydopamine solution for 24 h and vacuum dried at 60 ℃ for 6 h to obtain polydopamine-coated melamine sponge.

[0042] 1.4 parts by weight of methacrylate-functionalized polydimethylsiloxane and 0.2 parts by weight of ethylene glycol dimethacrylate were dispersed in 40 parts by weight of n-hexane, and the mixture was ultrasonically treated for 30 min to form a prepolymer solution. A pre-prepared polydopamine-coated melamine sponge was immersed in this prepolymer solution, removed after 10 min, and cured and dried at 80°C for 10 h to obtain the target sponge material.

[0043] Comparative Example 3 First, 5 parts by weight of dopamine hydrochloride, 5 parts by weight of tris(hydroxymethyl)aminomethane hydrochloride, and 1.6 parts by weight of potassium hydroxide were dissolved in 500 parts by weight of water and stirred thoroughly (stirring speed 500 rpm, stirring time 24 h) to obtain a polydopamine solution. Melamine sponge was then soaked in this polydopamine solution for 24 h and vacuum dried at 60 ℃ for 6 h to obtain polydopamine-coated melamine sponge.

[0044] 1.4 parts by weight of hydroxyl-terminated polydimethylsiloxane (OH-PDMS), 0.2 parts by weight of ethylene glycol dimethacrylate (EDGMA), and 0.07 parts by weight of silica nanoparticles were dispersed in 40 parts by weight of n-hexane and ultrasonically treated for 30 min to form a prepolymer solution. A pre-prepared polydopamine-coated melamine sponge was immersed in this prepolymer solution, removed after 10 min, and cured and dried at 80°C for 10 h to obtain the target sponge material.

[0045] The sponge materials prepared in the examples and comparative examples were subjected to performance tests, and the test methods are as follows: a. Adsorption time of 0.5 g crude oil: The time it takes for the oil droplet to be completely adsorbed by the sponge is recorded by adding 0.5 g of crude oil to the surface of the sponge.

[0046] b. Crude oil adsorption rate and crude oil adsorption capacity: First, record the original mass of the sponge, then immerse it in the oil for 2 minutes, wipe off the excess liquid on the surface, weigh it, and calculate the crude oil adsorption capacity using formula (1) and the crude oil adsorption rate using formula (2): Formula (1); Formula (2); In the formula, m0 and m1 are the masses of the sponge before and after oil absorption, t is the adsorption time, and A is the adsorption area. The results are shown in Table 1.

[0047] Table 1

[0048] As shown in Table 1, the sponge prepared using MA-PDMS, due to the presence of polymerizable methacrylate groups at its ends, can undergo cross-linking reactions during curing, forming a denser hydrophobic network structure. This effectively enhances the material's hydrophobic properties and crude oil adsorption capacity (Comparative Example 1). The introduction of EGDMA allows MA-PDMS to undergo more complete chemical cross-linking reactions, forming a denser and more stable three-dimensional hydrophobic network structure, further improving the material's hydrophobic properties and crude oil adsorption capacity (Comparative Example 2). The addition of silica nanoparticles further enhances the sponge's hydrophobic properties, and its light-induced heating, crude oil adsorption rate, and crude oil adsorption capacity are also improved (Example). In contrast, although the sponge prepared using OH-PDMS has a certain degree of hydrophobicity, its molecular chain ends are hydroxyl groups, lacking reactive functional groups, and cannot form chemical bonds with the melamine sponge skeleton. This results in poor coating stability and an inability to construct an ideal micro / nano rough structure, leading to unsatisfactory photothermal properties and crude oil adsorption rate (Comparative Example 3).

[0049] As can be seen above, MA-PDMS and EGDMA construct a stable hydrophobic network foundation, while silica further optimizes the surface microstructure. The synergistic effect of these three components optimizes the material's hydrophobicity, photothermal conversion efficiency, and crude oil adsorption performance. This design concept embodies a dual regulatory strategy of "cross-linked network + micro / nano structure." The resulting sponge material not only enhances hydrophobicity by increasing surface roughness, but more importantly, it creates a light trapping effect—the micro / nano structure causes incident light to undergo multiple reflections and scatterings on the coating surface, significantly increasing the light propagation path within the material, thereby improving light absorption efficiency and photothermal conversion efficiency. Consequently, under illumination, the material surface temperature rises more rapidly, and the viscosity of high-viscosity crude oil decreases rapidly, thus increasing the permeation and adsorption rates of crude oil within the material.

[0050] Figure 2 Scanning electron microscope (SEM) images of the polydopamine-coated melamine sponge, hydrophobic photothermal sponge material prepared in the examples, and the hydrophobic photothermal sponge material prepared in Comparative Example 3. As can be seen from the images, compared to the original MS sponge, the PDA@MS sponge loaded only with PDA, and the hydrophobic photothermal sponge material prepared using OH-PDMS in Comparative Example 3, the photothermal hydrophobic sponge prepared in the examples has a rougher surface structure, which can effectively construct a waterproof gas film and increase the contact area with crude oil, thereby achieving the effect of rapid crude oil adsorption.

[0051] The polydopamine-coated melamine sponge and hydrophobic photothermal sponge materials prepared in the examples were tested using a UV-Vis-NIR spectrophotometer (Cary 7000, Agilent). The results are shown in [Figure number missing]. Figure 4 .Depend on Figure 4It can be seen that in the wavelength range of 200-1400 nm, the original MS sponge exhibits high reflectivity and weak light absorption, while the PDA@MS sponge shows a synergistic effect of broadband light absorption. The photothermal hydrophobic sponge has a good light absorption and utilization rate, indicating that it has excellent light absorption performance.

[0052] The polydopamine-coated melamine sponge, hydrophobic photothermal sponge material prepared in the examples, and the hydrophobic photothermal sponge material prepared in Comparative Example 3 were analyzed using an infrared thermal imager (ETS 320, FTIR, USA) at a power output of 1.0 kW / m². 2 The photothermal conversion performance was tested under simulated illumination for different durations, and the results are shown below. Figure 5 .Depend on Figure 5 As can be seen, compared with the original MS sponge, PDA@MS and the hydrophobic photothermal sponge material prepared by OH-PDMS in Comparative Example 3, the hydrophobic photothermal sponge material prepared in the examples can efficiently absorb solar energy and convert it into thermal energy, demonstrating its great potential in the field of photothermal applications.

[0053] Figure 6 The photothermal hydrophobic sponge prepared for the example was at 0.5 kW / m 2 1.0 kW / m 2 1.5 kW / m 2 2.0 kW / m 2 The graph shows the change in photothermal conversion performance under simulated illumination. As can be seen from the graph, the illumination increases from 0.5 kW / m². 2 Increased to 2 kW / m 2 The surface temperature rose from 55.4℃ to 139.2℃, further proving that the obtained photothermal hydrophobic sponge can efficiently absorb solar energy and convert it into heat energy.

[0054] Figure 7 The hydrophobic photothermal sponge material prepared for the example has a power output of 1.0 kW / m². 2 The graph shows the photothermal conversion performance after 10 cycles of simulated illumination. As shown in the figure, the photothermal hydrophobic sponge exhibits excellent alternating photothermal heating behavior.

[0055] Figure 8 The hydrophobic photothermal sponge material prepared for this example operates in the dark and at 1.0 kW / m². 2 Comparison of crude oil adsorption under simulated illumination. As can be seen from the figure, at 1 kW / m²... 2 Under simulated sunlight, the hydrophobic photothermal sponge absorbs oil in just 60 seconds, achieving a 24-fold efficiency improvement compared to the MS sponge.

[0056] Figure 9The compression-release cycle performance of the polydopamine-coated melamine sponge, hydrophobic photothermal sponge material prepared in the examples, and the hydrophobic photothermal sponge material prepared in Comparative Example 3 are shown in the figures. As can be seen from the figures, compared with the original MS sponge, the PDA@MS sponge loaded only with PDA, and the hydrophobic photothermal sponge material prepared using OH-PDMS in Comparative Example 3, the photothermal hydrophobic sponge prepared in the examples has a higher structural strength.

[0057] Figure 10 The figures show the changes in water contact angle of the hydrophobic photothermal sponge materials prepared in Examples 1 and 2 (Comparative Example 3) after immersion in artificial seawater at different pH values ​​for 7 days. As can be seen from the figures, the hydrophobic photothermal sponge materials prepared in Examples 1 and 2 (Comparative Example 3) exhibit better chemical stability.

[0058] In summary, this invention selects green, environmentally friendly, and low-cost organic polymers and successfully prepares hydrophobic photothermal sponge materials by constructing their cross-linking networks. The preparation process is simple and easy to control, and the resulting material has excellent photothermal conversion performance and crude oil adsorption efficiency. It has broad application prospects and excellent value for large-scale application.

[0059] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a hydrophobic photothermal sponge material for oil spill recovery, characterized in that, Includes the following steps: (1) Immerse the melamine sponge in a dopamine solution to allow the dopamine to undergo a self-polymerization reaction on the surface of the melamine sponge. Then remove and dry it to obtain a polydopamine-coated melamine sponge. (2) The methacrylate-functionalized polydimethylsiloxane, crosslinking agent, and silica nanoparticles are dispersed in an organic solvent and mixed uniformly by ultrasonication to form a prepolymer solution; (3) The polydopamine-coated melamine sponge obtained in step (1) is immersed in the prepolymer solution in step (2) so that the prepolymer is fully adsorbed into the sponge. Then it is taken out and heated to cure, thereby constructing a micro-nano composite hydrophobic coating containing silica nanoparticles on the surface of the polydopamine coating through a chemical cross-linking reaction, so as to obtain the hydrophobic photothermal sponge material.

2. The method for preparing the hydrophobic photothermal sponge material according to claim 1, characterized in that, The mass concentration of the dopamine solution used in step (1) is 2~2.5 g / L.

3. The method for preparing the hydrophobic photothermal sponge material according to claim 1, characterized in that, The temperature of the self-polymerization reaction in step (1) is 25°C and the time is 24h.

4. The method for preparing the hydrophobic photothermal sponge material according to claim 1, characterized in that, The mass ratio of methacrylate-functionalized polydimethylsiloxane, crosslinking agent, and silica nanoparticles used in step (2) is 70:10:3.5; wherein the crosslinking agent is ethylene glycol dimethacrylate.

5. The method for preparing the hydrophobic photothermal sponge material according to claim 1 or 4, characterized in that, The methacrylate-functionalized polydimethylsiloxane is prepared by mixing hydroxyl-terminated polydimethylsiloxane, KH-570, dibutyltin dilaurate, and deionized water, stirring and reacting at room temperature for 12 hours, and then distilling the reaction mixture under reduced pressure at 60°C for 2 hours to remove residual water and unreacted small molecules; wherein the mass ratio of hydroxyl-terminated polydimethylsiloxane, KH-570, dibutyltin dilaurate, and deionized water is 100:15:0.5:

1.

6. The method for preparing the hydrophobic photothermal sponge material according to claim 1, characterized in that, The organic solvent mentioned in step (2) is one or more of N,N-dimethylformamide, dimethyl sulfoxide, and n-hexane.

7. The method for preparing the hydrophobic photothermal sponge material according to claim 1, characterized in that, The mass concentration of the prepolymer solution obtained in step (2) is 150~175 g / L.

8. The method for preparing the hydrophobic photothermal sponge material according to claim 1, characterized in that, In step (3), the melamine sponge coated with polydopamine is immersed in the prepolymer solution for 1 to 20 minutes.

9. The method for preparing the hydrophobic photothermal sponge material according to claim 1, characterized in that, The heating and curing temperature in step (3) is 60~100 ℃ and the time is 1~10 h.

10. A hydrophobic photothermal sponge material for oil spill recovery prepared by the method according to any one of claims 1-9.

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