A method for preparing an underwater superoleophobic copper mesh with anti-oil adhesion and its application.

Abstract

This invention relates to the field of metal materials and application technology, and particularly to a method for preparing an underwater superoleophobic copper mesh with anti-oil adhesion and its application. The preparation method includes the following steps: S1, providing a copper mesh coated with nano-copper hydroxide; S2, dissolving urea, copper sulfate, and nickel sulfate in water, wherein the Cu / Ni molar ratio is 1:3.5-5, and then placing the resulting solution and the copper mesh coated with nano-copper hydroxide in a high-pressure hydrothermal reactor for hydrothermal reaction at 90-95℃ to obtain the underwater superoleophobic copper mesh. Experiments show that the underwater oil contact angle of the aforementioned superoleophobic copper mesh can reach 153.24°, exhibiting excellent anti-oil adhesion performance. Furthermore, it shows significant resistance to friction and acid and alkali corrosion under harsh conditions. The modified copper mesh of this invention still has a high water flux after recovery and separation (>60 kL / (h·m)). 2 It can be reused.

Description

Technical Field

[0001] This invention relates to the field of metal materials and application technology, and in particular to a method for preparing an underwater superoleophobic copper mesh that resists oil adhesion and its application, including a method for preparing an underwater superoleophobic copper mesh and its application in oil-water separation. Background Technology

[0002] Metallic materials possess advantages such as low cost, high plasticity, good thermal stability, and excellent mechanical properties. Therefore, separation membranes made of metal meshes with special wettability have been widely used. This special wettability can be achieved by chemically modifying the surface of porous metal meshes using physical and chemical methods. The key to constructing hydrophilic and underwater superhydrophobic large-scale membranes is to utilize hydrophilic materials to create rough surfaces with micro / nano hierarchical structures and low surface energy. Subsequently, many superhydrophobic porous metal separation membranes can be prepared through coating methods, layer-by-layer self-assembly (LBL), oxidation methods, electrochemical deposition methods, and electrostatic methods. Among these, spinning and chemical deposition methods have been successfully used in the preparation of oil-water separation materials.

[0003] Copper mesh, a common type of metal filter, possesses strong toughness and stability. Due to copper's excellent electrical conductivity, the fabrication of specialized wettable surfaces using copper mesh as a substrate has been a research hotspot in recent years. Among numerous research findings, copper hydroxide nanostructures have demonstrated superior performance in specialized wettability. Copper hydroxide possesses a favorable nanostructure and hydrophilic functional groups, making it suitable for constructing specialized wettable surfaces. However, conventional oleophilic / superhydrophobic copper meshes experience a significant decrease in separation efficiency after oil-water separation due to oil clogging the mesh pores.

[0004] Currently, nickel (Ni(II)) is widely used in the modification of metal meshes to improve oil-water separation efficiency. However, there is little research on how to use Ni to control the nanostructure of rough surfaces to make them more ordered, thereby reducing surface energy, and this requires further specialized research and improvement. Summary of the Invention

[0005] To address the significant problem of decreased separation efficiency caused by oil clogging the mesh after oil-water separation in conventional oleophilic / superhydrophobic copper meshes, this invention provides a method for preparing an underwater superoleophobic copper mesh with anti-oil adhesion and its application. The preparation method provided by this invention can construct an ordered multilayer nanostructure on the surface of the copper mesh, thereby obtaining a high-throughput, anti-oil adhesion underwater superoleophobic oil-water separation material, which is beneficial for application.

[0006] This invention provides a method for preparing an underwater superoleophobic copper mesh that resists oil adhesion, comprising the following steps:

[0007] S1. Provides nano-coated copper mesh with copper hydroxide coating;

[0008] S2. Dissolve urea, copper sulfate and nickel sulfate in water, wherein the Cu / Ni molar ratio is 1:3.5-5. Then place the resulting solution and the nano-coated copper hydroxide mesh in a high-pressure hydrothermal reactor and carry out a hydrothermal reaction at a temperature of 90-95℃ to obtain an underwater superoleophobic copper mesh.

[0009] In an embodiment of the present invention, the nano-copper hydroxide coated copper mesh is obtained by the following operation:

[0010] The copper mesh is placed in a mixed solution of sodium hydroxide, (NH4)2S2O8 and water for etching. After etching, the copper mesh is washed with water and dried.

[0011] In an embodiment of the present invention, the copper mesh is a 500-mesh phosphor bronze mesh, and the drying is performed at 50-60°C.

[0012] In an embodiment of the present invention, the copper mesh is first washed with acetone, ethanol and water respectively, and then placed in the mixed solution.

[0013] In an embodiment of the present invention, the mass of the urea is 0.5-0.6g, and the mass of the copper sulfate is 0.3-0.5g.

[0014] In an embodiment of the present invention, the hydrothermal reaction takes 2-4 hours, after which the material is washed with water and dried to obtain an underwater superoleophobic copper mesh.

[0015] The present invention provides an underwater superoleophobic copper mesh prepared by the method described above, the surface of which has a nano-block protrusion structure and an underwater oil contact angle of more than 150°.

[0016] This invention provides the application of underwater superoleophobic copper mesh as described above in oil-water separation.

[0017] Compared with existing technologies, this invention uses nano-copper hydroxide to coat a copper mesh, and then grows nano-bulb protrusions on the surface of the copper mesh through a high-pressure hydrothermal reaction under certain conditions, thereby obtaining a modified copper mesh material. This is a high-flux underwater superoleophobic copper mesh that can be used for oil-water separation. This invention modifies the copper mesh to obtain a special ordered bulk protruding nanostructure, giving the copper mesh surface low surface energy and resistance to oil adhesion. Experiments show that the underwater superoleophobic copper mesh can achieve an underwater oil contact angle of 153.24°, exhibiting excellent anti-oil adhesion performance. Furthermore, it demonstrates significant resistance to friction and acid / alkali corrosion under harsh conditions. In this embodiment, the modified copper mesh still has a high water flux after recovery and separation (>60 kL / (h·m)). 2 ))), can be reused. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the hydrothermal synthesis process provided in an embodiment of the present invention;

[0020] Figure 2 SEM images of copper mesh materials constructed with different Cu / Ni molar ratios in Example 1 of this invention;

[0021] Figure 3 This is a diagram of the separation device and testing process in Embodiment 2 of the present invention;

[0022] Figure 4 The results are from the oil-water separation test in Example 2 of this invention;

[0023] Figure 5 This refers to the separation efficiency of NBCPCM in Example 2 of the present invention for repeatedly separating the n-hexane / water mixture 30 times;

[0024] Figure 6 The chemical stability test results of NBCPCM in Example 2 of this invention;

[0025] Figure 7 This is a diagram illustrating the mechanical stability test process in Embodiment 2 of the present invention;

[0026] Figure 8 The results are the mechanical stability test results in Embodiment 2 of the present invention. Detailed Implementation

[0027] The technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0028] This invention provides a method for preparing an underwater superoleophobic copper mesh that resists oil adhesion, comprising the following steps:

[0029] S1. Provides nano-coated copper mesh with copper hydroxide coating;

[0030] S2. Dissolve urea, copper sulfate and nickel sulfate in water, wherein the Cu / Ni molar ratio is 1:3.5-5. Then place the resulting solution and the nano-coated copper hydroxide mesh in a high-pressure hydrothermal reactor and carry out a hydrothermal reaction at a temperature of 90-95℃ to obtain an underwater superoleophobic copper mesh.

[0031] The method of this invention can obtain copper mesh materials with ordered multilayer nanostructures on the surface, which can be used as underwater superoleophobic oil-water separation materials. It has the characteristics of high throughput, anti-oil adhesion, and reusability, and has a wide range of application prospects.

[0032] See Figure 1 , Figure 1 This is a schematic diagram of the hydrothermal synthesis process provided in an embodiment of the present invention. In this embodiment, a copper mesh (CM) is first etched to obtain a copper mesh coated with nano-copper hydroxide (CHCM), and then subjected to hydrothermal synthesis ireaction to obtain a nickel-doped copper nanoparticle protrusion coated copper mesh (NBCPCMs), which is the aforementioned underwater superoleophobic copper mesh.

[0033] In this embodiment of the invention, the copper hydroxide nanostructure coated copper mesh (CHCM) is first prepared: Specifically, a clean copper mesh is placed in a mixed solution composed of sodium hydroxide solution, (NH4)2S2O8 solution and water (generally deionized water), and etched for a certain period of time. Finally, the etched copper mesh is washed with water and dried (preferably at 50-60°C) to obtain the final product.

[0034] In step S1 of this embodiment of the invention, the cleaned copper mesh is obtained by the following method: the copper mesh, which is cut into 2cm×2cm pieces, is washed in an ultrasonic instrument with acetone, ethanol and water for 5-15 minutes respectively; the copper mesh is preferably 500 mesh phosphor bronze mesh, which can be commercially available, such as from Anping Pangsen Wire Mesh Manufacturing Co., Ltd.

[0035] In the specific preparation of the mixed solution described in the embodiments of the present invention, the concentration of sodium hydroxide solution is 4-5 mol / L, and the volume is 80-100 mL; the concentration of (NH4)2S2O8 solution is 0.4-0.6 mol / L, preferably 0.5 mol / L, and the volume is 30-50 mL, preferably 40 mL; the volume of water can be 80-100 mL, such as 90 mL, just enough to completely immerse the copper mesh. In the embodiments of the present invention, the surface is left at room temperature for at least 30 minutes, preferably 1 hour, to allow the copper mesh surface to be uniformly etched to form a certain copper hydroxide nanostructure. The copper hydroxide nanostructure exhibits excellent performance in terms of special wettability. Copper hydroxide has a good nanostructure and hydrophilic functional groups on its surface, making it suitable for constructing surfaces with special wettability. The etched copper mesh surface is a copper hydroxide nanostructure. This structure has poor acid resistance and is unstable, requiring a high-quality solvent environment, but its rough structure provides a large number of reaction sites. Therefore, in the field of oil-water separation, etched copper mesh is often used as a substrate for intermediate reactions.

[0036] Then, in this embodiment of the invention, the material is further modified to prepare nickel-doped copper nanoparticle protrusion-coated copper mesh (NBCPCMs). The NBCPCMs described in this embodiment are prepared by hydrothermal synthesis under high pressure. Specifically, urea, copper sulfate (e.g., CuSO4·5H2O), and nickel sulfate (e.g., NiSO4·6H2O) are dissolved in water, wherein the Cu / Ni molar ratio is 1:3.5-5, preferably 1:4; the mixture is magnetically stirred for 5-15 minutes. The resulting solution and CHCM are then placed in a hydrothermal synthesis reactor, which is placed in an oven and reacted at 90℃-95℃ for 2-4 hours. Afterward, the modified copper mesh is washed with water and dried.

[0037] In a preferred embodiment of the present invention, the mass of the urea is 0.5-0.6 g, the mass of the copper sulfate (CuSO4·5H2O) is 0.3-0.5 g, and the mass of the nickel sulfate (NiSO4·6H2O) is 1.4-1.6 g. The solution is dissolved in deionized water, with a volume of 80-100 mL, to obtain a raw material solution for modification.

[0038] In a specific embodiment of the present invention, the raw material solution and the nano-coated copper hydroxide mesh are placed in a high-pressure hydrothermal reactor and subjected to a hydrothermal reaction at a temperature of 90-95°C. Regarding the reaction pressure, since the reaction is generally carried out in a closed reactor (e.g., 100-150 mL volume) in an oven, a precise reaction pressure cannot be given. The term "high pressure" is relative to atmospheric pressure in an open environment. At 90-95°C, preferably 90°C, the temperature increases, leading to a higher pressure in the closed container environment. The hydrothermal reaction time is 2-4 hours, preferably 3 hours at 90°C. The drying process preferably refers to drying in a 60°C oven for 12 hours to obtain a dried underwater superoleophobic copper mesh (denoted as NBCPCM).

[0039] Accordingly, this invention provides an underwater superoleophobic copper mesh (NBCPCM) prepared by the method described above, the surface of which has a nano-bulb protrusion structure. The underwater superoleophobicity generally refers to an underwater oil contact angle of 150° or higher.

[0040] In an embodiment of the present invention, the water contact angle of the NBCPCM is 25.43°; the underwater oil (n-hexane) contact angle of the NBCPCM is 153.24°.

[0041] Furthermore, this invention also provides the application of the aforementioned underwater superoleophobic copper mesh in oil-water separation. The modified copper mesh of this invention resists oil adhesion and exhibits significant resistance to abrasion and acid / alkali corrosion under harsh conditions. It is reusable, and its water flux remains high after recovery and separation (>60 kL / h·m). 2 ))).

[0042] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention. Unless otherwise specified, the reagents and materials described in the following embodiments are commercially available.

[0043] Example 1

[0044] (1) Preparation of copper hydroxide nanostructured coated copper mesh (CHCM)

[0045] A 2cm x 2cm copper mesh (purchased from Anping Pangsen Wire Mesh Manufacturing Co., Ltd., 500-mesh phosphor bronze mesh) was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each. The cleaned copper mesh was then placed in a mixed solution consisting of 80 mL of sodium hydroxide solution (5 mol / L), 40 mL of (NH₄)₂S₂O₈ solution (0.5 mol / L), and 90 mL of deionized water for 1 hour. Finally, the etched copper mesh was rinsed with deionized water and dried in a 60℃ oven for 12 hours.

[0046] (2) Preparation of nickel-doped hydrated copper sulfate nanobulb protrusions coated with copper mesh (NBCPCMs)

[0047] 0.579 g of urea, 0.342 g of CuSO4·5H2O (copper sulfate pentahydrate), and 1.438 g of NiSO4·6H2O (nickel sulfate hexahydrate) were weighed and dissolved in 80 mL of deionized water, with a Cu / Ni molar ratio of 1:4. The solution was then magnetically stirred for 10 minutes. The resulting solution and CHCM were then placed in a hydrothermal synthesis reactor (150 mL volume), which was placed in an oven. After reacting at 90 °C for 3 hours, the modified copper mesh was washed with deionized water and dried in an oven at 60 °C for 12 hours to obtain the final product.

[0048] This embodiment characterized the microscopic surface morphology of the obtained modified copper mesh material and compared different Cu / Ni molar ratios. See details below. Figure 2 Scanning electron microscope (SEM) image.

[0049] Figure 2 In the images, (a) shows the surface morphology of the original copper mesh; (b) shows the surface morphology of the copper mesh coated with copper hydroxide nanosheets after etching; (c) shows the surface morphology of the copper mesh constructed with a Cu:Ni molar ratio of 1:1; (d) shows the surface morphology of the copper mesh constructed with a Cu:Ni molar ratio of 1:2; (e) shows the surface morphology of the copper mesh constructed with a Cu:Ni molar ratio of 1:3; and (f) shows the surface morphology of the copper mesh constructed with a Cu:Ni molar ratio of 1:4.

[0050] Furthermore, traditional water bath reactions (such as at 85°C and ambient pressure) easily form grafted nanosheet structures. However, the modified copper mesh surface in Example 1 of this application exhibits nanobulb protrusions that are relatively more ordered; the fundamental reason for the difference in surface morphology is likely due to the different reaction conditions and variables. In this application, under conditions of 90°C and increased ambient pressure, the effect of different copper-nickel molar ratios on the surface structure of the copper mesh was observed. The SEM images clearly show that the surface construction process in this application involves hydrothermal synthesis under certain ambient pressure, where Ni is doped onto the copper mesh surface and uniformly grown to form nanobulb protrusion structures.

[0051] Example 2

[0052] The NBCPCM prepared in Example 1 was subjected to the following performance tests:

[0053] (1) Hydrophilic and oleophobic properties test

[0054] The water contact angle of the NBCPCM is 25.43°.

[0055] The underwater oil (n-hexane) contact angle of NBCPCM is 153.24°.

[0056] Air contact angle test:

[0057] Add a test water droplet to the syringe and slowly bring the needle close to the surface of the copper mesh. When the water droplet leaves the needle and drips onto the surface of the copper mesh, due to the hydrophilic nature of the copper mesh, the water droplet on the surface of the copper mesh forms an arc shape. Then, the contact angle of the water droplet on the surface of the copper mesh is measured using a contact angle measuring instrument.

[0058] Underwater oil contact angle test content and methods:

[0059] The prepared copper mesh was placed flat on top of a transparent rectangular glass container filled with water, and the copper mesh was wetted by the water. A test oil droplet (n-hexane) was added to a syringe, and the needle was slowly inserted underwater and brought close to the surface of the copper mesh. When the oil droplet left the needle and rose to the lower surface of the copper mesh, due to the underwater superoleophobic properties of the prepared copper mesh, the lower surface of the copper mesh supported the oil droplet, causing it to maintain a regular spherical shape underwater. The contact angle of the oil droplet on the underwater copper mesh surface was then measured using a contact angle measuring instrument.

[0060] (2) Oil-water separation efficiency test

[0061] Clamp a fully wetted mesh (NBCPCM, used as a sample) with a glass tube fitted with a clamp. Prepare a simple separation apparatus with a diameter of approximately 3 cm. Place a beaker underneath to collect and observe the filtered liquid. Pour 48 mL of an oil-water mixture (oil / water volume ratio Voil / Vwater = 1:2) into the separation apparatus and filter by gravity to test the separation efficiency and recycling performance. To clearly observe the oil-water separation process, dye the organic solvent orange with Sudan II and the water blue with methylene blue. The separation process is as follows: Figure 3 As shown. Before separation, the modified copper mesh needs to be pre-wetted with water. The oil-water separation efficiency η of the copper mesh can be calculated according to equation (1).

[0062]

[0063] Where η is the oil-water separation efficiency (%), m0 is the initial water mass (g), and m1 is the permeate mass (g).

[0064] The oils contained were hexane, cyclohexane, pump oil, soybean oil, and ligroin. The separation results are as follows: Figure 4 As shown.

[0065] The separation efficiency of NBCPCM for different oil-water mixtures is as follows: Figure 4 As shown, the efficiency is greater than 90%, and the separation efficiency for cyclohexane / water mixtures is as high as 98.54%, indicating that the copper mesh is universally applicable to various types of oil-water mixtures.

[0066] (3) Membrane flux test

[0067] Membrane flux refers to the volume of liquid permeating the material per unit time and unit area, reflecting the separation rate of the material and is an important indicator of oil-water separation materials. An oil-water separation membrane was placed on a filter device, and then 48 mL of an oil-water mixture was poured in. The time required for complete separation of the oil-water mixture was recorded. Membrane flux is defined by equation (2):

[0068]

[0069] Where Flux is the separation flux (L / m 2 ·h), V is the permeate volume (L), and A is the effective filtration area of ​​the filter screen (m²). 2 ), where Δt is the separation time (h).

[0070] Accordingly, a cycle performance test was conducted: the NBCPCM filter membrane was cycle tested using the above separation device and a hexane / water mixture.

[0071] The separation efficiency of NBCPCM for a hexane / water mixture after 30 repeated separations is as follows: Figure 5 As shown, even after 30 cycles, the water flux is still greater than 60 kL / (h·m). 2 )).

[0072] (4) Chemical stability test

[0073] The chemical resistance of NBCPCM was tested after wetting it in acidic and alkaline solutions with different pH values. Using concentrated hydrochloric acid, sodium hydroxide, potassium permanganate, and a pH meter, the pH of the aqueous solution was adjusted to 2, 4, 6, 8, 10, and 12, respectively. A prepared copper mesh sample of NBCPCM was placed in each of these six solutions, immersed for 12 hours, and then removed, dried, and its oil-water separation efficiency was measured to determine its chemical stability. The results are as follows: Figure 6 As shown, their separation efficiencies are all above 97%.

[0074] (5) Mechanical stability test

[0075] A weight of 100g was fixed on the top of the copper mesh sample NBCPCM. After clamping it with tweezers, it was subjected to uniform sliding abrasion on 600-grit sandpaper at a speed of 2.0m / s. The change in oil-water separation efficiency of the sample was tested during 300 abrasion cycles. The test procedure is as follows: Figure 7 As shown, see the results. Figure 8 .

[0076] Figure 8 The results show that the separation efficiency of the NBCPCM copper mesh sample remained above 80% after 300 wear cycles. This embodiment of the invention utilizes a hydrothermal synthesis modification method under certain environmental pressure, which allows the reactants to be more uniformly and firmly loaded onto the copper mesh surface, improving the material's mechanical strength (see SEM images for details). Furthermore, friction cycle experiments demonstrate that the modified copper mesh material still exhibits excellent oil-water separation performance even after multiple friction cycles.

[0077] As can be seen from the above embodiments, this invention uses nano-copper hydroxide to coat a copper mesh, and then grows nano-bulb protrusions on the surface of the copper mesh through a high-pressure hydrothermal reaction under certain conditions, thereby obtaining a modified copper mesh material; it is a high-flux underwater superoleophobic copper mesh that can be used for oil-water separation. This invention modifies the copper mesh to obtain a special ordered bulk protruding nanostructure, resulting in a low surface energy and an underwater oil contact angle of 153.24°, exhibiting excellent anti-oil adhesion performance. Furthermore, the underwater superoleophobic copper mesh shows significant resistance to friction and acid / alkali corrosion under harsh conditions. The modified copper mesh of this invention still has a high water flux after recovery and separation (>60 kL / (h·m)). 2 ))), can be reused.

[0078] The descriptions of the above embodiments are merely illustrative of the methods and core ideas of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an underwater superoleophobic copper mesh with anti-oil adhesion, characterized in that, The method comprises the following steps: S1. providing a copper mesh coated with nano copper hydroxide, wherein the copper mesh coated with nano copper hydroxide is obtained by the following operation: placing a copper mesh into a mixed solution composed of sodium hydroxide, (NH4)2S2O8 and water, and placing for etching, then washing the etched copper mesh with water, and drying; the copper mesh is a 500-mesh phosphor copper mesh, which is washed with acetone, ethanol and water respectively before being placed into the mixed solution; the drying is drying at 50-60°C; S2. dissolving urea, copper sulfate and nickel sulfate in water, wherein the Cu / Ni molar ratio is 1:3.5-5, then placing the obtained solution and the copper mesh coated with nano copper hydroxide into a high-pressure hydrothermal reaction kettle, and performing hydrothermal reaction at a temperature of 90-95°C, wherein the hydrothermal reaction time is 2-4h, then washing with water, and drying to obtain an underwater super-oil-repellent copper mesh, which has a nano block-shaped protruding structure on the surface.

2. The method of claim 1, wherein the underwater superoleophobic copper mesh is prepared by the steps of: The mass of the urea is 0.5-0.6g, and the mass of the copper sulfate is 0.3-0.5g.

3. The method for preparing underwater superoleophobic copper mesh according to any one of claims 1-2, characterized in that, The underwater super-oil-repellent copper mesh has an underwater oil contact angle of 150° or more.

4. Application of the underwater super-oil-repellent copper mesh obtained by the preparation method according to any one of claims 1-3 in oil-water separation.

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