High-flux long-acting oil-water separation coating and preparation method thereof

Abstract

The invention discloses a high-flux long-acting oil-water separation coating and a preparation method thereof. The preparation method comprises the following steps: dissolving polydimethylsiloxane in ethyl acetate to prepare a polydimethylsiloxane solution; and dipping diatomite in a polydimethylsiloxane solution, and drying until the ethyl acetate is completely volatilized, thereby obtaining the siloxane modified diatomite. The preparation method comprises the following steps: diluting a phenolic resin adhesive with a mixed solvent to form a phenolic resin dispersion system, then adding siloxane modified diatomite into the phenolic resin adhesive dispersion system, and uniformly dispersing to obtain the siloxane modified diatomite-phenolic resin coating. A stainless steel metal grid or melamine sponge is coated with the diatomite-phenolic resin coating, and the diatomite-phenolic resin coating is obtained after heating and curing. The coating constructed by the invention has super-oleophylic and super-hydrophobic characteristics, and can be applied to efficient separation of an oil-water mixture with wide specific gravity in a severe environment. Meanwhile, the coating can be coated on flexible base materials such as sponge, so that the application prospect of the coating in antifouling clothes, medical treatment and industrial special materials is expanded.

Description

Technical Field

[0001] The present invention belongs to the field of functional coating preparation or construction, and particularly relates to a high-throughput long-lasting oil-water separation coating and a preparation method thereof. Background Art

[0002] With the development of regional industrialization and the global economy, oil pollution from the catering industry, the discharge of organic wastewater, and marine oil pollution have become environmental issues that cannot be ignored. These oil pollutions not only endanger the balance of aquatic ecosystems, but also pose a major threat to human health and socioeconomic development. Traditional oil-water separation methods such as gravity sedimentation, centrifugation, and flotation, while achieving significant results under certain conditions, generally have limitations such as high cost, low efficiency, and susceptibility to secondary pollution. Given the urgent need for efficient and economical oil-water separation, the development of inexpensive, environmentally friendly, and long-lasting oil-water separation technologies with engineering serviceability (salt spray, ocean, and ultraviolet) has great scientific significance and potential application value.

[0003] In recent years, with the development of interface theory and bionics, superoleophilic and superhydrophobic coatings have become a research hotspot in the field of oil-water separation due to their unique advantages in oil-water separation. This coating achieves selective separation of oil and water by imitating structures in nature such as the lotus leaf effect or fish scales. The design of the superoleophilic surface allows the oil to spread and adhere quickly, while the superhydrophobic property allows water droplets to form a high contact angle, making it difficult to wet the surface, thereby effectively separating the two liquids. The special functionality and convenient construction of superoleophilic and superhydrophobic coatings are conducive to promoting engineering applications and are one of the effective technologies to solve the pollution caused by traditional oil-water separation technology. However. Affected by environmental media (strong acid, strong alkali, salt spray, seawater, ultraviolet), the engineering performance of superoleophilic and superhydrophobic oil-water separation coatings during service not only puts forward higher requirements (high oil-water separation efficiency, high oil-water separation flux), but also needs to maintain its long-term oil-water separation performance in this harsh environment. But at present super oleophilic and super hydrophobic oil-water separation coating faces the technical bottleneck that engineering performance (oil-water separation efficiency, oil-water separation flux) weakens under harsh working conditions, and part test environment is all under laboratory conditions, for the long-term stability of coating under harsh environment, anti-pollution ability and the continuous separation performance under high-throughput conditions, still lacks systematic in-depth research. Make its actual engineering application subject to certain restrictions. And preparation method is still faced with many challenges such as high material cost, complex process flow and being difficult to realize large-scale preparation. Super oleophilic and super hydrophobic oil-water separation coating patent such as: patent CN105999769A selects zirconium phenylphosphonate and polytetrafluoroethylene compounding to prepare super oleophilic and super hydrophobic oil-water separation coating, but because of its complex process, material cost is high, do not possess engineering usability. And patent CN104404503A proposes to be coated on metal grid and prepare super oleophilic and super hydrophobic oil-water separation coating after carbon nanotube and siloxane polymer blend. Despite their excellent hydrophobicity and oil-water separation efficiency, there is a lack of evaluation of their oil-water separation performance (high separation efficiency and high throughput) under harsh engineering application environments. This makes it difficult to ensure long-term, high-performance oil-water separation under engineering service conditions. Therefore, it is necessary to develop new superoleophilic and superhydrophobic oil-water separation coating technologies that are inexpensive, long-lasting, and high-throughput. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a diatomaceous earth natural nanopore, high-throughput, long-lasting oil-water separation coating with a simple preparation method and low cost, and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A method for preparing a high-throughput, long-lasting oil-water separation coating comprises the following steps:

[0007] S1, dissolving polydimethylsiloxane in ethyl acetate solvent to prepare a polydimethylsiloxane solution;

[0008] S2. Take diatomaceous earth powder and immerse it in polydimethylsiloxane solution and let it stand at room temperature for 4-6 hours. Then put it in an oven and dry it until the ethyl acetate is completely volatilized. The resulting powder is siloxane-modified diatomaceous earth;

[0009] S3, diluting the phenolic resin adhesive with a mixed solvent to form a phenolic resin adhesive dispersion system; taking the siloxane-modified diatomaceous earth prepared in step S2, adding it to the phenolic resin adhesive dispersion system, and uniformly dispersing it to obtain a siloxane-modified diatomaceous earth-phenolic resin coating;

[0010] S4. Using a one-step spraying method, the siloxane-modified diatomaceous earth-phenolic resin coating prepared in step S3 is applied to the degreased and cleaned stainless steel metal grid to obtain a metal grid-based coating wet film; or using a dip coating method, a melamine sponge is dipped into the siloxane-modified diatomaceous earth-phenolic resin coating prepared in step S3, and then the melamine sponge is removed and excess coating is squeezed out to obtain a sponge-based coating wet film;

[0011] S5. Curing the metal grid-based coating wet film or the sponge-based coating wet film prepared in step S4 to obtain a high-throughput and long-lasting oil-water separation coating.

[0012] Preferably, in the above-mentioned method for preparing the high-throughput and long-lasting oil-water separation coating, the mixed solvent in step S3 is formed by mixing ethanol, ethyl acetate and acetone in a volume ratio of 1:1:1.

[0013] Preferably, in the above-mentioned method for preparing the high-throughput and long-lasting oil-water separation coating, the diatomaceous earth, polydimethylsiloxane, acetone, ethyl acetate and ethanol are all of analytical grade.

[0014] Preferably, in the above-mentioned method for preparing the high-throughput and long-lasting oil-water separation coating, the mass fraction of polydimethylsiloxane in the polydimethylsiloxane solution in step S1 is 10-12%.

[0015] Preferably, in the above-mentioned method for preparing a high-throughput and long-lasting oil-water separation coating, the drying temperature in step S2 is 70-90° C., and the volume ratio of the diatomaceous earth to polydimethylsiloxane is 1-1.5:1.

[0016] Preferably, in the above-mentioned method for preparing a high-throughput and long-lasting oil-water separation coating, the siloxane-modified diatomaceous earth-phenolic resin coating in step S3 has a coating viscosity of 14-18s.

[0017] Preferably, in the above-mentioned method for preparing a high-throughput and long-lasting oil-water separation coating, the time for immersing the melamine sponge in the siloxane-modified diatomaceous earth-phenolic resin coating in step S4 is 5-8 minutes.

[0018] Preferably, in the above-mentioned method for preparing the high-throughput and long-lasting oil-water separation coating, the curing temperature in step S5 is 180° C., and the curing time is 1.5-2 hours.

[0019] Preferably, in the above-mentioned method for preparing a high-throughput and long-lasting oil-water separation coating, the solid volume fraction of the siloxane-modified diatomaceous earth in the siloxane-modified diatomaceous earth-phenolic resin coating in step S3 is 15-20%.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The metal grid-based coating after spraying of the present invention has superoleophilic and superhydrophobic properties, with a water contact angle (WCA) of 152.3° and a sliding angle (WSA) of 15°.

[0022] (2) The metal grid-based coating after spraying of the present invention has excellent separation efficiency (>97.1%) and separation flux (1×10 4 -8.3×10 4 L / (m 2 h)). (3) The metal grid-based coating after spraying of the present invention has good oil-water separation reusability. After 40 oil-water separation cycles, the coating still maintains an oil-water separation efficiency of more than 98%.

[0023] (4) The metal grid-based coating after spraying of the present invention has excellent acid and alkali resistance stability, the WCA of different acid, alkali and salt media on the coating is greater than 145°, and the oil-water separation efficiency is stable at more than 98.1%.

[0024] (5) The metal grid-based coating after spraying of the present invention has the comprehensive performance of long-term resistance to salt spray, seawater and UV. Under the action of 96h salt spray, artificial seawater and UV radiation, the coating shows long-term hydrophobicity (WCA>132°) and oil-water separation efficiency (>98.1%). (6) The present invention can also be coated on flexible substrates such as sponges. The prepared sponge-based coating has excellent oil-water separation performance, which expands its broad prospects from environmental protection equipment to anti-fouling clothing, medical and industrial special materials, and provides new ideas for the design of high-throughput, high-efficiency and long-term oil-water separation coating materials in harsh engineering environments.

[0025] (7) The coating constructed by the present invention has superoleophilic and superhydrophobic properties, and can be used for the efficient separation of a wide range of oil-water mixtures (dichloromethane, n-hexane, petroleum ether, kerosene, lubricating oil) in harsh environments (high temperature, strong alkali, strong acid, salt spray, seawater, ultraviolet), and is expected to be applied to the fields of catering oil and water treatment, industrial organic wastewater treatment, and marine oil pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Figure 3 is a diagram of the macroscopic oil and water wettability behavior of the metal grid-based coating surface, where Figure a shows the superoleophilic and superhydrophobic properties, Figure b shows the static contact angle of water, Figure c shows the rolling angle, Figure d shows the SEM image of the coating, Figure e shows the oil-water separation process, Figure f shows the oil-water separation efficiency, and Figure g shows the separation flux;

[0027] Figure 2 Figure 2 is an oil-water separation efficiency diagram, where Figure a shows the separation efficiency of the metal grid-based coating as the number of separation cycles of kerosene and water mixtures changes, and Figure b shows the oil-water separation efficiency of kerosene and different acid-base media mixtures passing through the metal grid-based coating;

[0028] Figure 3 Figure 1 is a diagram of the metal grid-based coating after 96 hours of environmental adaptability testing (salt spray, artificial seawater, and UV), and a diagram of the macroscopic oil and water wettability behavior of the metal grid-based coating surface. Figure b is the water contact angle, and Figure c is the oil-water separation efficiency.

[0029] Figure 4 These are the effects of coating the sponge, where Figure a is a macroscopic digital image, Figure b is a slice image, and Figure c is the macroscopic process of oil-water separation. DETAILED DESCRIPTION

[0030] The following is a further description of specific embodiments of the present invention. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0031] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0032] Example 1: Preparation of a diatomaceous earth natural nanoporous, high-throughput, long-lasting oil-water separation coating

[0033] (1) 10 g of polydimethylsiloxane was dissolved in 90 g of ethyl acetate to prepare a 10 wt.% polydimethylsiloxane solution.

[0034] (2) Weigh 2 g of diatomaceous earth and immerse it in 10 ml of a 10 wt.% polydimethylsiloxane solution. After standing at room temperature for 4 h, place it in an oven set at 70°C and dry until the ethyl acetate is completely evaporated. The resulting powder is siloxane-modified diatomaceous earth.

[0035] (3) 6.6 g of phenolic resin adhesive was diluted with 40 ml of a mixed solvent (ethanol, ethyl acetate, and acetone, in a volume ratio of 1:1:1) to prepare a phenolic resin dispersion system. 2 g of siloxane-modified diatomaceous earth was weighed and added to the phenolic resin dispersion system and uniformly dispersed to prepare a siloxane-modified diatomaceous earth-phenolic resin coating.

[0036] (4) Clean and scrub the 300-mesh 304 stainless steel mesh substrate with an organic solvent such as acetone or petroleum ether until the surface is free of oily fingerprints. Spray a 4-cup coating with a viscosity of 17s onto the 300-mesh 304 stainless steel mesh substrate using a W-101 spray gun from a vertical distance of 15 cm. Repeat the spraying three times with an interval of 5 minutes to obtain a wet film coating.

[0037] (5) The wet coating film prepared in step S4 was cured at 180°C for 1.5h to obtain a diatomaceous earth natural nanopore, high-throughput, long-lasting oil-water separation coating material. The coating surface has super oleophilic and hydrophobic properties ( Figure 1 a), the water static contact angle is 152.3°( Figure 1 b), the roll angle is 15° ( Figure 1 c). Through different separation processes, the coating can achieve the separation of heavy oil and water as well as light oil and water. Under the action of the phenolic resin adhesive system, the siloxane-modified diatomaceous earth accumulates and agglomerates with each other, forming a rough double micro-nano structure on the surface ( Figure 1 d). This structure further promotes the superoleophilicity and superhydrophobicity of the coating. A mixture of heavy oil (dichloromethane) and water is poured into the coating grid fixed between the glass tubes. The water phase first contacts the coating but cannot penetrate the grid, while the dichloromethane that arrives later is able to smoothly wet and pass through the coating grid, successfully achieving the separation of dichloromethane and water. After separation, no observable oil phase residue is found in the water phase. An inclined separation device is used to separate the mixture of light oil (n-hexane, petroleum ether, kerosene, lubricating oil) and water. When water does not completely cover the coating grid, the light oil (n-hexane, petroleum ether, kerosene, lubricating oil) can touch and smoothly penetrate the coating grid. There is no visible oil phase residue in all separated phases ( Figure 1 e). Further quantitative analysis of the separation efficiency and separation flux of the coating for oil-water mixtures with different specific gravities ( Figure 1fg), the separation efficiency of kerosene and water is as high as 99.6%, and the separation efficiency of other oil-water mixtures exceeds 97.1%. As the oil phase viscosity increases from 0.33 cSt to 22 cSt, the oil flux gradually decreases. Among them, the oil flux of low viscosity dichloromethane (0.33 cSt) is as high as 8.3×10 4 L / (m2·h). However, the oil flux of high viscosity lubricating oil (22cSt) can still reach 1×10 4 The oil-water separation efficiency and oil flux test results prove that the coating has excellent oil-water separation capabilities and can efficiently complete the oil-water separation task in a short time.

[0038] Example 2: Preparation of a diatomaceous earth natural nanoporous, high-throughput, long-lasting oil-water separation coating

[0039] (1) 12 g of polydimethylsiloxane was dissolved in 88 g of ethyl acetate to prepare a 12 wt.% polydimethylsiloxane solution.

[0040] (2) Weigh 2.4 g of diatomaceous earth and soak it in 10 ml of 12 wt.% polydimethylsiloxane solution. After standing at room temperature for 4 hours, put it into an oven set at 70°C and dry it until the ethyl acetate is completely evaporated. The resulting powder is siloxane-modified diatomaceous earth.

[0041] (3) 8.4 g of phenolic resin adhesive was diluted with 45 ml of a mixed solvent (ethanol, ethyl acetate, and acetone, in a volume ratio of 1:1:1) to an appropriate viscosity to prepare a phenolic resin dispersion system. 2.4 g of siloxane-modified diatomaceous earth was weighed and added to the phenolic resin dispersion system and uniformly dispersed to prepare a siloxane-modified diatomaceous earth-phenolic resin coating.

[0042] (4) Clean and scrub the 300-mesh 304 stainless steel metal grid substrate with an organic solvent such as acetone or petroleum ether until there is no oily fingerprint on the surface. Use a W-101 spray gun to spray a 4-cup coating with a viscosity of 15s onto the surface of the 300-mesh 304 stainless steel metal grid substrate from a vertical distance of 15 cm. Repeat the spraying 3 times with an interval of 5 minutes to obtain a coating wet film.

[0043] (5) The wet coating film prepared in step S4 was cured at 180°C for 2 hours to obtain a diatomaceous earth natural nanoporous, high-flux, long-lasting oil-water separation coating material. After 40 kerosene and water separation experiments, the separation efficiency of the coating continued to remain above 98% ( Figure 2 a). The wettability and oil-water separation efficiency of the diatomite-based coating grid in various acidic and alkaline media such as room temperature water (25°C), hot water (90°C), HCl solution (pH=1), NaCl solution (3.5wt.%) and NaOH solution (pH=13) were further investigated. The results showed that the oil-water separation efficiency exceeded 98.1% ( Figure 2 b).

[0044] Example 3: Preparation of a diatomaceous earth natural nanoporous, high-throughput, long-lasting oil-water separation coating

[0045] (1) 12 g of polydimethylsiloxane was dissolved in 88 g of ethyl acetate to prepare a 12 wt.% polydimethylsiloxane solution.

[0046] (2) Weigh 2.4 g of diatomaceous earth and soak it in 10 ml of 12 wt.% polydimethylsiloxane solution. After standing at room temperature for 5 h, put it into an oven set at 85°C and dry until the ethyl acetate is completely evaporated. The resulting powder is siloxane-modified diatomaceous earth.

[0047] (3) 8.4 g of phenolic resin adhesive was diluted with 45 ml of a mixed solvent (ethanol, ethyl acetate, and acetone, in a volume ratio of 1:1:1) to an appropriate viscosity to prepare a phenolic resin dispersion system. 2.4 g of siloxane-modified diatomaceous earth was weighed and added to the phenolic resin dispersion system and uniformly dispersed to prepare a siloxane-modified diatomaceous earth-phenolic resin coating.

[0048] (4) Clean and scrub the 300-mesh 316L stainless steel metal grid substrate with an organic solvent such as acetone or petroleum ether until there is no oily fingerprint on the surface. Use a W-101 spray gun to spray a 4-cup coating with a viscosity of 15s onto the surface of the 300-mesh 316L stainless steel metal grid substrate from a vertical distance of 15 cm. Repeat the spraying 3 times with an interval of 5 minutes to obtain a coating wet film.

[0049] (5) The wet coating film prepared in step S4 was cured at 180°C for 2h to obtain a diatomaceous earth natural nanoporous, high-throughput, long-lasting oil-water separation coating material. The coating has super oleophilic and super hydrophobic properties. After 96h of environmental adaptability test (salt spray, artificial seawater, ultraviolet), the coating still maintains good hydrophobicity and oleophilicity ( Figure 3 a), the coating was subjected to salt spray corrosion, artificial seawater immersion and UV irradiation experiments, and the macroscopic wettability, water contact angle (WCA) change and oil-water separation efficiency of the coating were tested at different time points (12h, 24h, 48h, 96h) ( Figure 3 b). The experimental results show that compared with the water contact angle of the original coating (WCA = 150.3°-153.4°), the water contact angle of the coating decreased by about 10% (138°-140°) after 12 hours and remained above 132° for 24-96 hours. In addition, the oil-water separation efficiency of the coating only slightly decreased by about 1% (98.1%–99%) compared with the original coating (99.2-99.6%) from 12 to 96 hours ( Figure 3 c).

[0050] Example 4: Preparation of Diatomaceous Earth Natural Nanopore, High-throughput Long-lasting Oil-Water Separation Coating

[0051] (1) 12 g of polydimethylsiloxane was dissolved in 88 g of ethyl acetate to prepare a 12 wt.% polydimethylsiloxane solution.

[0052] (2) Weigh 2.7 g of diatomaceous earth and soak it in 10 ml of a 12 wt.% polydimethylsiloxane solution. After standing at room temperature for 6 h, place it in an oven set at 80°C and dry until the ethyl acetate is completely evaporated. The resulting powder is siloxane-modified diatomaceous earth.

[0053] (3) 8.4 g of phenolic resin adhesive was diluted with 40 ml of a mixed solvent (ethanol, ethyl acetate, and acetone, in a volume ratio of 1:1:1) to an appropriate viscosity to prepare a phenolic resin dispersion system. 2.4 g of siloxane-modified diatomaceous earth was weighed and added to the phenolic resin dispersion system, and the siloxane-modified diatomaceous earth-phenolic resin coating was uniformly dispersed to prepare a coating having a coating viscosity of 16s after 4 cups.

[0054] (4) Clean the melamine sponge with ethanol until the surface is free of oil. Use tweezers to hold the melamine sponge and immerse it in the silicone-modified diatomaceous earth-phenolic resin coating for 5 minutes. Then take it out and squeeze out the excess coating from the sponge to prepare a wet film of the sponge-based coating.

[0055] (5) The wet coating film prepared in step S4 was cured at 180°C for 1.5h to obtain a sponge-based diatomaceous earth natural nanopore, high-throughput, long-lasting oil-water separation coating material. The sponge-based material after coating was reddish brown ( Figure 4 a), and after further cutting it into slices, it was found that the cross section of the slices was also reddish brown ( Figure 4 b). This indicates that the siloxane-modified diatomaceous earth-phenolic resin coating has successfully penetrated into the interior of the sponge, achieving effective modification of the sponge from the outside to the inside. After the sponge-based diatomaceous earth natural nanopore, high-throughput long-lasting oil-water separation coating is placed in an oil-water mixture with tweezers, it quickly absorbs the oil phase on the water surface and does not absorb the water phase. After it is taken out after floating for a while, it is observed that there is no visible oil phase remaining in the oil-water mixture. This proves that the modified sponge has selective adsorption capacity ( Figure 4 c).

[0056] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations of these embodiments may be made without departing from the principles and spirit of the present invention, and the changes still fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-throughput and long-lasting oil-water separation coating, characterized in that: The following steps are involved: S1, dissolving polydimethylsiloxane in ethyl acetate solvent to prepare a polydimethylsiloxane solution; S2. Take diatomaceous earth powder and immerse it in polydimethylsiloxane solution and let it stand at room temperature for 4-6 hours. Then put it in an oven and dry it until the ethyl acetate is completely volatilized. The resulting powder is siloxane-modified diatomaceous earth; S3, diluting the phenolic resin adhesive with a mixed solvent to form a phenolic resin adhesive dispersion system; taking the siloxane-modified diatomaceous earth prepared in step S2, adding it to the phenolic resin adhesive dispersion system, and uniformly dispersing it to obtain a siloxane-modified diatomaceous earth-phenolic resin coating; S4. Using a one-step spraying method, the siloxane-modified diatomaceous earth-phenolic resin coating prepared in step S3 is applied to the degreased and cleaned stainless steel metal grid to obtain a metal grid-based coating wet film; or using a dip coating method, a melamine sponge is dipped into the siloxane-modified diatomaceous earth-phenolic resin coating prepared in step S3, and then the melamine sponge is removed and excess coating is squeezed out to obtain a sponge-based coating wet film; S5. Curing the metal grid-based coating wet film or the sponge-based coating wet film prepared in step S4 to obtain a high-throughput and long-lasting oil-water separation coating.

2. The method for preparing a high-throughput and long-lasting oil-water separation coating according to claim 1, characterized in that: The mixed solvent described in step S3 is prepared by mixing ethanol, ethyl acetate and acetone in a volume ratio of 1:1:

1.

3. The method for preparing a high-throughput, long-lasting oil-water separation coating according to claim 2, characterized in that: The diatomaceous earth, polydimethylsiloxane, acetone, ethyl acetate and ethanol were all of analytical grade.

4. The method for preparing a high-throughput and long-lasting oil-water separation coating according to claim 1, wherein: In the polydimethylsiloxane solution described in step S1, the mass fraction of polydimethylsiloxane is 10-12%.

5. The method for preparing a high-throughput and long-lasting oil-water separation coating according to claim 1, characterized in that: The drying temperature in step S2 is 70-90° C., and the volume ratio of the diatomaceous earth to polydimethylsiloxane is 1-1.5:

1.

6. The method for preparing a high-throughput and long-lasting oil-water separation coating according to claim 1, characterized in that: The siloxane-modified diatomaceous earth-phenolic resin coating described in step S3 has a coating viscosity of 14-18s in a 4-cup pan.

7. The method for preparing a high-throughput and long-lasting oil-water separation coating according to claim 1, characterized in that: In step S4, the time for immersing the melamine sponge in the silicone-modified diatomaceous earth-phenolic resin coating is 5-8 minutes.

8. The method for preparing a high-throughput and long-lasting oil-water separation coating according to claim 1, characterized in that: The curing temperature in step S5 is 180° C., and the curing time is 1.5-2 hours.

9. The method for preparing a high-throughput and long-lasting oil-water separation coating according to claim 1, characterized in that: In step S3, the solid volume fraction of the siloxane-modified diatomaceous earth in the siloxane-modified diatomaceous earth-phenolic resin coating is 15-20%.

10. A high-throughput, long-lasting oil-water separation coating, characterized in that Prepared by the preparation method according to any one of claims 1 to 9.

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