Super-hydrophobic activated carbon coating material, and preparation method and application thereof

Abstract

The application belongs to the technical field of oil-water separation and emulsion demulsification, and relates to a super-hydrophobic activated carbon coating material and a preparation method and application thereof. The preparation method comprises the following processes: washing activated carbon to expose hydroxyl groups on the surface of the activated carbon; reacting the washed activated carbon with organic silane in an alkaline system containing water, so that the organic silane is hydrolyzed and chemically bonded with the hydroxyl groups on the surface of the activated carbon, and the organic silane grafted on the surface of the activated carbon is polymerized, to obtain super-hydrophobic activated carbon; wherein the alkyl carbon number of the organic silane is not less than 10; and the super-hydrophobic activated carbon is uniformly mixed with a resin binder in a solvent, to obtain the coating material. The coating material is prepared by using super-hydrophobic activated carbon, and has the advantages of low price, firmness and durability, excellent performance, simple preparation process and the like, and can be widely applied to the fields of oil-water separation and emulsion demulsification.

Description

Technical Field

[0001] This invention belongs to the field of oil-water separation and emulsion demulsification technology, and relates to a superhydrophobic activated carbon coating material, its preparation method and application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] With the rapid development of industry and transportation, the discharge of oily wastewater is constantly increasing, posing a serious threat to the ecological environment and human health. Traditional oil-water separation methods, such as gravity separation and natural sedimentation, have drawbacks such as low separation efficiency, long processing cycles, and easy generation of secondary pollution, making it difficult to meet the growing environmental protection demands. Therefore, developing efficient and environmentally friendly oil-water separation technologies has become the focus of current research.

[0004] Superhydrophobic materials, with their unique surface properties, have shown great application potential in oil-water separation and emulsion demulsification. Superhydrophobic materials possess a static contact angle greater than 150° and a roll-off angle less than 10°, effectively repelling water molecules while attracting oil molecules, thus achieving oil-water separation and emulsion demulsification. In recent years, researchers have prepared superhydrophobic materials using various methods and applied them to oil-water separation, achieving significant results. However, the inventors have found that in existing technologies, most superhydrophobic materials commonly use expensive micro / nanomaterials (such as graphene oxide and carbon nanotubes) to construct surface roughness. For example, patent publication CN117861448A discloses a superhydrophobic oil-water separation membrane prepared using nano-zinc oxide and graphene oxide, which exhibits good oily wastewater treatment efficiency. However, the high cost of nano-zinc oxide and graphene oxide, coupled with the complex preparation process of this oil-water separation material, limits its large-scale application. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a superhydrophobic activated carbon coating material, its preparation method, and its application. The present invention utilizes superhydrophobic activated carbon to make a coating material, which has the advantages of low price, durability, excellent performance, and simple preparation process, and can be widely used in fields such as oil-water separation and emulsion demulsification.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] In a first aspect, a method for preparing a superhydrophobic activated carbon coating material includes the following steps:

[0008] Clean the activated carbon until its surface hydroxyl groups are exposed;

[0009] The cleaned activated carbon is reacted with organosilane in an alkaline system containing water, causing the organosilane to hydrolyze and chemically bond with the hydroxyl groups on the surface of the activated carbon, while the organosilane grafted on the surface of the activated carbon is polymerized to obtain superhydrophobic activated carbon; wherein the organosilane has an alkyl carbon number of not less than 10.

[0010] The superhydrophobic activated carbon and resin binder are mixed evenly in a solvent to obtain the final product.

[0011] Currently, methods for modifying activated carbon into hydrophobic / superhydrophobic activated carbon include: surface passivation, removal of hydrophilic groups, hydrophobic modification by oxide loading, grafting of surface groups, organosilicon coating, and nano-coating. Among these, the methods for modifying activated carbon into superhydrophobic activated carbon mainly involve organosilicon coating and nano-coating. However, the superhydrophobic activated carbon coatings prepared by these methods are mainly composited through physical methods such as deposition. When using them as superhydrophobic components to prepare coating materials, the coating is prone to swelling in the solvent due to the need for mixing with a binder, which causes the coating to detach from the activated carbon. This reduces or even eliminates the superhydrophobic properties of the prepared coating material. Therefore, it is quite difficult to directly prepare superhydrophobic activated carbon coating materials using existing superhydrophobic activated carbon.

[0012] This invention exposes the hydroxyl groups on the surface of activated carbon through cleaning. Using these hydroxyl groups as active sites, silanols derived from the hydrolysis of organosilanes are chemically grafted onto the activated carbon surface, resulting in hydrophobic long carbon chains with a carbon number of not less than 10. Under alkaline conditions, the organosilanes with hydrophobic long carbon chains are polymerized, thereby firmly fixing the hydrophobic long carbon chains on the activated carbon surface to form superhydrophobic activated carbon. Then, the superhydrophobic activated carbon is mixed with a resin binder in a solvent to ensure that the hydrophobic long carbon chains do not detach from the activated carbon surface, thus guaranteeing the superhydrophobic properties of the superhydrophobic activated carbon coating material.

[0013] On the other hand, a superhydrophobic activated carbon coating material is obtained by the above preparation method.

[0014] Thirdly, a superhydrophobic activated carbon coating is provided, wherein the superhydrophobic activated carbon coating material is attached to the surface of a substrate.

[0015] Fourthly, the application of the aforementioned superhydrophobic activated carbon coating material or superhydrophobic activated carbon coating in oil-water separation and / or emulsion demulsification.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. The superhydrophobic activated carbon coating material prepared by this invention is obtained by modifying activated carbon with organosilanes to obtain superhydrophobic activated carbon, mixing it with an epoxy resin solution, and then uniformly coating it onto a substrate. The activated carbon surface has a large number of hydroxyl groups. After hydrolysis, the organosilanes polymerize on the activated carbon surface under alkaline conditions, thereby grafting a large number of hydrophobic long carbon chains onto the activated carbon, achieving superhydrophobic modification. This modification method is simple to operate, inexpensive, and produces activated carbon with excellent hydrophobic properties.

[0018] 2. The superhydrophobic activated carbon coating material prepared by this invention has the advantages of low price, durability, excellent performance and simple preparation process, and can be widely used in the fields of oil-water separation and emulsion demulsification. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 The FTIR Fourier transform infrared spectra of the superhydrophobic activated carbon obtained in Example 1 and the superhydrophobic activated carbon obtained in Example 2 of this invention are shown below.

[0021] Figure 2 The image shows a scanning electron microscope (SEM) image of the 300-mesh superhydrophobic activated carbon coating obtained in Example 1 of this invention. a is a low magnification image, and b is a high magnification image.

[0022] Figure 3 The image shows a scanning electron microscope (SEM) image of the 2000-mesh superhydrophobic activated carbon coating obtained in Example 2 of this invention. a is a low magnification image, and b is a high magnification image.

[0023] Figure 4 This is a water contact angle diagram of the 300-mesh superhydrophobic activated carbon coated mesh prepared in Example 1 of the present invention;

[0024] Figure 5 This is an oil (chloroform) contact angle diagram of the 300-mesh superhydrophobic activated carbon coated mesh obtained in Example 1 of the present invention;

[0025] Figure 6 This is a water contact angle diagram of the 2000-mesh superhydrophobic activated carbon coated mesh prepared in Example 2 of the present invention;

[0026] Figure 7 This is an oil (chloroform) contact angle diagram of the 2000-mesh superhydrophobic activated carbon coated mesh obtained in Example 2 of the present invention;

[0027] Figure 8The image shows the change in water contact angle of the 300-mesh superhydrophobic activated carbon coated mesh prepared in Example 1 of this invention during the durability performance test. a represents ultrasonic treatment, b represents tape peeling, c represents baking at different temperatures, and d represents immersion in different pH solutions and seawater.

[0028] Figure 9 This is a schematic diagram showing the oil-water separation efficiency of the 300-mesh superhydrophobic activated carbon coated mesh prepared in Example 1 of the present invention for five oil-water mixtures.

[0029] Figure 10 This is a schematic diagram showing the efficiency and separation flux of the 300-mesh superhydrophobic activated carbon coated mesh obtained in Example 1 of the present invention for separating a chloroform-water mixture in ten consecutive cycles.

[0030] Figure 11 This is a schematic diagram of the separation experiment of the demulsification efficiency of five kinds of water-in-oil emulsions using a 2000-mesh superhydrophobic activated carbon coated mesh prepared in Example 2 of the present invention.

[0031] Figure 12 This is a water contact angle diagram of the 300-mesh superhydrophobic activated carbon coated mesh prepared in Comparative Example 1 of this invention;

[0032] Figure 13 The oil (chloroform) contact angle diagram of the 300-mesh superhydrophobic activated carbon coated mesh prepared in Comparative Example 1 of this invention;

[0033] Figure 14 This is a water contact angle diagram of the 300-mesh superhydrophobic activated carbon coating mesh prepared in Comparative Example 2 of this invention;

[0034] Figure 15 The oil (chloroform) contact angle diagram of the 300-mesh superhydrophobic activated carbon coated mesh prepared in Comparative Example 2 of this invention;

[0035] Figure 16 This is a water contact angle diagram of the 300-mesh superhydrophobic activated carbon coating mesh prepared in Comparative Example 3 of the present invention;

[0036] Figure 17 This is an oil (chloroform) contact angle diagram of the 300-mesh superhydrophobic activated carbon coated mesh prepared in Comparative Example 3 of the present invention. Detailed Implementation

[0037] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0038] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] Given that the materials used in existing oil-water coatings are relatively expensive, and the present invention has found that activated carbon, which is relatively inexpensive, is difficult to use as a superhydrophobic coating material after being modified into a superhydrophobic material using existing methods, the present invention proposes a superhydrophobic activated carbon coating material, its preparation method and application.

[0040] A typical embodiment of the present invention provides a method for preparing a superhydrophobic activated carbon coating material, comprising the following steps:

[0041] Clean the activated carbon until its surface hydroxyl groups are exposed;

[0042] The cleaned activated carbon is reacted with organosilane in an alkaline system containing water, causing the organosilane to hydrolyze and chemically bond with the hydroxyl groups on the surface of the activated carbon, while the organosilane grafted on the surface of the activated carbon is polymerized to obtain superhydrophobic activated carbon; wherein the organosilane has an alkyl carbon number of not less than 10.

[0043] The superhydrophobic activated carbon and resin binder are mixed evenly in a solvent to obtain the final product.

[0044] In some embodiments, the activated carbon is wood-based activated carbon, coconut shell activated carbon, or coal-based activated carbon. Specifically, the particle size of the activated carbon is 200-500 mesh.

[0045] In some embodiments, the activated carbon is washed sequentially with ethanol and water. This allows for better exposure of the hydroxyl groups on the surface of the activated carbon.

[0046] In some embodiments, the cleaned activated carbon is added to an alcohol solvent and dispersed evenly, then water is added, and the pH of the solvent system is adjusted to alkaline. Then, an organosilane is added to initiate the reaction. Dispersing the activated carbon evenly before adding the organosilane facilitates sufficient contact between the organosilane and the activated carbon surface, ensuring the grafting efficiency of the hydrophobic long carbon chains on the activated carbon surface and improving the superhydrophobic properties of the superhydrophobic activated carbon. Specifically, ultrasonic dispersion is used to ensure uniform dispersion of the activated carbon in the alcohol solvent. The alcohol solvent used in this invention is a liquid alcoholic organic compound, such as methanol, ethanol, propanol, ethylene glycol, etc., which is miscible with water, thus facilitating the reaction.

[0047] In some embodiments, the mass ratio of organosilane to activated carbon is (0.5–1.2):1.

[0048] The alkaline system described in this invention is a reaction system with a pH greater than 7. In some embodiments, the pH value of the alkaline system is 9-11. The pH of the alkaline system can be adjusted using ammonia, sodium hydroxide solution, etc.

[0049] In some embodiments, the mass ratio of water added to activated carbon is (1-2):1.

[0050] In some embodiments, the organosilane is one or a combination of dodecyltrichlorosilane, hexadecyltrichlorosilane, octadecyltrichlorosilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltriethoxysilane, and octadecyltriethoxysilane.

[0051] In some embodiments, the reaction time is 6 to 12 hours.

[0052] In some embodiments, superhydrophobic activated carbon is added to an alcohol solvent and dispersed evenly, and then a resin binder solution is added. Dispersing the superhydrophobic activated carbon evenly beforehand facilitates uniform mixing with the resin binder, ensuring the stability of the superhydrophobic properties of the coating material.

[0053] In some embodiments, the resin adhesive is an epoxy resin and its curing agent. Specifically, the epoxy resin is type E51, and the curing agent is type W93.

[0054] Another embodiment of the present invention provides a superhydrophobic activated carbon coating material, which is obtained by the above preparation method.

[0055] A third embodiment of the present invention provides a superhydrophobic activated carbon coating, wherein the superhydrophobic activated carbon coating material is attached to the surface of a substrate.

[0056] In some embodiments, the adhesion method is coating. Coating methods include spraying, dripping, dipping, etc. After coating, curing is performed. The curing temperature is 60–120°C, and the curing time is 4–8 hours.

[0057] In some embodiments, the substrate is one or more of stainless steel mesh, cotton cloth, polyurethane foam, etc.

[0058] A fourth embodiment of the present invention provides an application of the above-mentioned superhydrophobic activated carbon coating material or superhydrophobic activated carbon coating in oil-water separation and / or emulsion demulsification.

[0059] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0060] Example 1

[0061] (1) After pulverizing the activated carbon, wash it in anhydrous ethanol and deionized water in sequence until it is neutral, and then dry it to obtain pretreated activated carbon.

[0062] (2) Add 5g of pretreated activated carbon to 80g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min, add 10g of water, and add ammonia to adjust the pH to 10 to obtain an activated carbon suspension.

[0063] (3) Add 5g of hexadecyltrimethoxysilane to the activated carbon suspension, stir magnetically for 6 hours, filter, and dry at 80℃ for 6 hours to obtain superhydrophobic modified activated carbon, such as Figure 1 As shown.

[0064] (4) Add 2g of superhydrophobic modified activated carbon to 50g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min to obtain a superhydrophobic modified activated carbon suspension.

[0065] (5) Add 1g of E51 type epoxy resin and 0.3g of W93 type curing agent to 4g of anhydrous ethanol, ultrasonically disperse for 10min and stir evenly until the solution is clear and transparent to obtain epoxy resin solution.

[0066] (6) Add the epoxy resin solution to the superhydrophobic modified activated carbon suspension and stir for 30 minutes to obtain the superhydrophobic activated carbon coating solution.

[0067] (7) Add the superhydrophobic activated carbon coating solution to the spray gun and spray it onto the surface of a 300-mesh stainless steel mesh. The distance between the spray gun and the substrate is 15cm, the spraying pressure is 0.5MPa, the moving speed is 3cm / s, and it is cured at 80℃ for 6 hours to obtain a 300-mesh superhydrophobic activated carbon coated mesh. Figure 2 As shown.

[0068] The 300-mesh superhydrophobic activated carbon coated mesh of this embodiment was subjected to wettability testing, durability testing, and oil-water separation efficiency testing.

[0069] The water contact angle of the 300-mesh superhydrophobic activated carbon coated mesh is 155.1°. Figure 4 As shown.

[0070] The oil contact angle of a 300-mesh superhydrophobic activated carbon coated mesh is approximately 0°, such as Figure 5 As shown.

[0071] The water roll-off angle of the 300-mesh superhydrophobic activated carbon coated mesh is 8.9°.

[0072] Durability tests were conducted on a 300-mesh superhydrophobic activated carbon coated mesh. After being subjected to 120W ultrasonic treatment for 300 minutes, 20 tape peeling cycles, calcination at 200℃ for 1 hour, and immersion in various pH solutions and seawater for 24 hours, the 300-mesh superhydrophobic activated carbon coated mesh still maintained its superhydrophobic properties. Figure 8 As shown.

[0073] Five oil-water mixtures (chloroform-water, chlorobenzene-water, n-hexane-water, gasoline-water, and sweet almond oil-water) were separated using a 300-mesh superhydrophobic activated carbon coated mesh. The oil-water separation efficiencies of the 300-mesh superhydrophobic activated carbon coated mesh for the five mixtures were determined to be 98.6%, 99.2%, 99.4%, 96.7%, and 96.5%, respectively, by measuring the water content in the mixtures before and after separation. Figure 9 As shown.

[0074] The efficiency and separation flux of separating a chloroform-water mixture using a 300-mesh superhydrophobic activated carbon coated mesh were tested in ten consecutive cycles. The efficiency was above 95% in each of the ten cycles, and the separation flux remained at 12000 L·m⁻¹. -2 ·h -1 ,like Figure 10 As shown.

[0075] Example 2

[0076] (1) After pulverizing the activated carbon, wash it in anhydrous ethanol and deionized water in sequence until it is neutral, and then dry it to obtain pretreated activated carbon.

[0077] (2) Add 10g of pretreated activated carbon to 200g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min, add 20g of water, and add ammonia to adjust the pH to 11 to obtain an activated carbon suspension.

[0078] (3) Add 20g of dodecyltriethoxysilane to the activated carbon suspension, stir magnetically for 12h, filter, and dry at 60℃ for 12h to obtain superhydrophobic modified activated carbon, such as Figure 1 As shown.

[0079] (4) Add 5g of superhydrophobic modified activated carbon to 50g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min to obtain a superhydrophobic modified activated carbon suspension.

[0080] (5) Add 2g of E51 epoxy resin and 0.5g of W93 curing agent to 10g of anhydrous ethanol, ultrasonically disperse for 10min and stir until the solution is clear and transparent to obtain epoxy resin solution.

[0081] (6) Add the epoxy resin solution to the superhydrophobic modified activated carbon suspension and stir for 30 minutes to obtain the superhydrophobic activated carbon coating solution.

[0082] (7) Add the superhydrophobic activated carbon coating solution to the spray gun and spray it onto the surface of a 2000-mesh stainless steel mesh. The distance between the spray gun and the substrate is 15cm, the spraying pressure is 0.5MPa, the moving speed is 3cm / s, and it is cured at a curing temperature of 60℃ for 8 hours to obtain a 2000-mesh superhydrophobic activated carbon coated mesh. Figure 3 As shown.

[0083] In this embodiment, the 2000-mesh superhydrophobic activated carbon coated mesh was used for wettability testing and oil-water separation efficiency testing.

[0084] The water contact angle of the 2000-mesh superhydrophobic activated carbon coated mesh is 154.5°. Figure 6 As shown.

[0085] The oil contact angle of a 2000-mesh superhydrophobic activated carbon coated mesh is approximately 0°, such as Figure 7 As shown.

[0086] The water roll-off angle of the 2000-mesh superhydrophobic activated carbon coated mesh is 9.3°.

[0087] Five water-in-oil emulsions (chloroform-water, chlorobenzene-water, n-hexane-water, and gasoline-water) were demulsified using a 2000-mesh superhydrophobic activated carbon coated mesh. The demulsification efficiencies of the 2000-mesh superhydrophobic activated carbon coated mesh for the five water-in-oil emulsions were determined to be 93.8%, 96.7%, 96.1%, and 94.2%, respectively, by measuring the water content in the emulsions before and after separation. Figure 11 As shown.

[0088] Comparative Example 1

[0089] (1) After pulverizing the activated carbon, wash it in anhydrous ethanol and deionized water in sequence until it is neutral, and then dry it to obtain pretreated activated carbon.

[0090] (2) Add 5g of pretreated activated carbon to 80g of anhydrous ethanol and disperse it by ultrasonication for 10min, then stir it by magnetic force for 10min to obtain an activated carbon suspension.

[0091] (3) Add 5g of hexadecyltrimethoxysilane to the activated carbon suspension, heat under reflux, stir magnetically for 6h, filter, and dry at 80℃ for 6h to obtain superhydrophobic modified activated carbon.

[0092] (4) Add 2g of superhydrophobic modified activated carbon to 50g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min to obtain a superhydrophobic modified activated carbon suspension.

[0093] (5) Add 1g of E51 type epoxy resin and 0.3g of W93 type curing agent to 4g of anhydrous ethanol, ultrasonically disperse for 10min and stir evenly until the solution is clear and transparent to obtain epoxy resin solution.

[0094] (6) Add the epoxy resin solution to the superhydrophobic modified activated carbon suspension and stir for 30 minutes to obtain the superhydrophobic activated carbon coating solution.

[0095] (7) Add the superhydrophobic activated carbon coating solution to the spray gun and spray it onto the surface of a 300-mesh stainless steel mesh. The distance between the spray gun and the substrate is 15cm, the spraying pressure is 0.5MPa, the moving speed is 3cm / s, and the coating is cured at 80℃ for 6h to obtain a 300-mesh superhydrophobic activated carbon coated mesh.

[0096] The wettability of the 300-mesh superhydrophobic activated carbon coated mesh in this comparative example was tested.

[0097] The water contact angle of the 300-mesh superhydrophobic activated carbon coated mesh is 135.6°, such as... Figure 12 As shown.

[0098] The oil contact angle of a 300-mesh superhydrophobic activated carbon coated mesh is approximately 0°, such as Figure 13 As shown.

[0099] The water roll-off angle of the 300-mesh superhydrophobic activated carbon coated mesh is 27.2°.

[0100] Compared to Example 1, Comparative Example 1 did not add water or adjust the pH to alkaline during the preparation of superhydrophobic activated carbon. The resulting 300-mesh superhydrophobic activated carbon coating did not exhibit superhydrophobic properties. The main reason is that the absence of water and pH adjustment prevents the organosilanes from hydrolyzing and polymerizing. Instead, the activated carbon undergoes surface physical adsorption through its porous structure to achieve superhydrophobic modification. However, during the subsequent addition of anhydrous ethanol, the organosilanes adsorbed on the activated carbon surface desorb due to ethanol rinsing, resulting in a 300-mesh superhydrophobic activated carbon coating that falls far short of the required superhydrophobic performance.

[0101] Comparative Example 2

[0102] (1) After pulverizing the activated carbon, wash it in anhydrous ethanol and deionized water in sequence until it is neutral, and then dry it to obtain pretreated activated carbon.

[0103] (2) Add 5g of pretreated activated carbon to 80g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min, and add 10g of water to obtain an activated carbon suspension.

[0104] (3) Add 5g of hexadecyltrimethoxysilane to the activated carbon suspension, heat under reflux, stir magnetically for 6h, filter, and dry at 80℃ for 6h to obtain superhydrophobic modified activated carbon.

[0105] (4) Add 2g of superhydrophobic modified activated carbon to 50g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min to obtain a superhydrophobic modified activated carbon suspension.

[0106] (5) Add 1g of E51 type epoxy resin and 0.3g of W93 type curing agent to 4g of anhydrous ethanol, ultrasonically disperse for 10min and stir evenly until the solution is clear and transparent to obtain epoxy resin solution.

[0107] (6) Add the epoxy resin solution to the superhydrophobic modified activated carbon suspension and stir for 30 minutes to obtain the superhydrophobic activated carbon coating solution.

[0108] (7) Add the superhydrophobic activated carbon coating solution to the spray gun and spray it onto the surface of a 300-mesh stainless steel mesh. The distance between the spray gun and the substrate is 15cm, the spraying pressure is 0.5MPa, the moving speed is 3cm / s, and the coating is cured at 80℃ for 6h to obtain a 300-mesh superhydrophobic activated carbon coated mesh.

[0109] The wettability of the 300-mesh superhydrophobic activated carbon coated mesh in this comparative example was tested.

[0110] The water contact angle of the 300-mesh superhydrophobic activated carbon coated mesh is 149.3°, such as... Figure 14 As shown.

[0111] The oil contact angle of a 300-mesh superhydrophobic activated carbon coated mesh is approximately 0°, such as Figure 15 As shown.

[0112] The water roll-off angle of the 300-mesh superhydrophobic activated carbon coated mesh is 13.7°.

[0113] Compared to Comparative Example 1 and Example 1, Comparative Example 2 did not adjust the pH to alkaline during the preparation of superhydrophobic activated carbon. The 300-mesh superhydrophobic activated carbon coating prepared in Comparative Example 2 exhibited higher hydrophobicity than Comparative Example 1, approaching superhydrophobicity, but failing to achieve true superhydrophobicity (water contact less than 150°). Failure to adjust the pH to alkaline prevents the further polymerization of silanols from the hydrolysis of organosilanes, thus failing to ensure the stable fixation of the hydrophobic long carbon chains on the activated carbon surface. Consequently, the subsequently prepared coating material cannot meet the requirements for superhydrophobic performance.

[0114] Comparative Example 3

[0115] (1) Pulverize and dry the activated carbon to obtain pretreated activated carbon.

[0116] (2) Add 5g of pretreated activated carbon to 80g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min, add 10g of water, and add ammonia to adjust the pH to 10 to obtain an activated carbon suspension.

[0117] (3) Add 5g of hexadecyltrimethoxysilane to the activated carbon suspension, heat under reflux, stir magnetically for 6h, filter, and dry at 80℃ for 6h to obtain superhydrophobic modified activated carbon.

[0118] (4) Add 2g of superhydrophobic modified activated carbon to 50g of anhydrous ethanol and ultrasonically disperse for 10min, then magnetically stir for 10min to obtain a superhydrophobic modified activated carbon suspension.

[0119] (5) Add 1g of E51 type epoxy resin and 0.3g of W93 type curing agent to 4g of anhydrous ethanol, ultrasonically disperse for 10min and stir evenly until the solution is clear and transparent to obtain epoxy resin solution.

[0120] (6) Add the epoxy resin solution to the superhydrophobic modified activated carbon suspension and stir for 30 minutes to obtain the superhydrophobic activated carbon coating solution.

[0121] (7) Add the superhydrophobic activated carbon coating solution to the spray gun and spray it onto the surface of a 300-mesh stainless steel mesh. The distance between the spray gun and the substrate is 15cm, the spraying pressure is 0.5MPa, the moving speed is 3cm / s, and the coating is cured at 80℃ for 6h to obtain a 300-mesh superhydrophobic activated carbon coated mesh.

[0122] The wettability of the 300-mesh superhydrophobic activated carbon coated mesh in this comparative example was tested.

[0123] The water contact angle of the 300-mesh superhydrophobic activated carbon coated mesh is 146.5°. Figure 16 As shown.

[0124] The oil contact angle of a 300-mesh superhydrophobic activated carbon coated mesh is approximately 0°, such as Figure 17 As shown.

[0125] The water roll-off angle of the 300-mesh superhydrophobic activated carbon coated mesh is 17.1°.

[0126] Compared to Example 1, Comparative Example 3, which used unwashed activated carbon, failed to achieve the required superhydrophobic properties (water contact less than 150°) in its 300-mesh superhydrophobic activated carbon coating. The main reason for this is that the unwashed activated carbon resulted in incomplete exposure of surface hydroxyl groups, leading to incomplete grafting for subsequent superhydrophobic modification and thus failing to meet the superhydrophobic performance requirements.

[0127] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of a superhydrophobic activated carbon coating material in oil-water separation, characterized in that, The preparation method of superhydrophobic activated carbon coating materials includes the following steps: The activated carbon was cleaned until its surface hydroxyl groups were exposed, wherein the activated carbon was washed sequentially with ethanol and water. The cleaned activated carbon is reacted with an organosilane in an alkaline system containing water, causing the organosilane to hydrolyze and chemically bond with the hydroxyl groups on the surface of the activated carbon. Simultaneously, the organosilane grafted onto the surface of the activated carbon is polymerized to obtain superhydrophobic activated carbon. The organosilane is one or a combination of dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltriethoxysilane, and octadecyltriethoxysilane. The superhydrophobic activated carbon and resin binder are mixed evenly in a solvent to obtain the final product. The mass ratio of organosilane to activated carbon is (0.5 ~ 1.2): 1; The pH value of an alkaline system is 9-11; The mass ratio of water to activated carbon is (1~2):1; The reaction time is 6-12 hours.

2. The application of the superhydrophobic activated carbon coating material as described in claim 1 in oil-water separation, characterized in that, The cleaned activated carbon was added to an alcohol solvent and dispersed evenly. Water was then added, and the pH of the solvent system was adjusted to alkaline. Then, an organosilane was added to carry out the reaction.

3. The application of the superhydrophobic activated carbon coating material as described in claim 1 in oil-water separation, characterized in that, Superhydrophobic activated carbon is added to an alcohol solvent and dispersed evenly, and then a resin binder solution is added.

4. The application of the superhydrophobic activated carbon coating material as described in claim 1 in oil-water separation, characterized in that, The resin adhesive is epoxy resin and its curing agent.

5. The application of the superhydrophobic activated carbon coating material as described in claim 1 in oil-water separation, characterized in that, The superhydrophobic activated carbon coating material is attached to the surface of a substrate to obtain a superhydrophobic activated carbon coating.

6. The application of the superhydrophobic activated carbon coating material as described in claim 5 in oil-water separation, characterized in that, The adhesion method is coating; Alternatively, the substrate may be one or more of stainless steel mesh, cotton cloth, and polyurethane foam.

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