Filtering membrane, filtering device and method for manufacturing filtering membrane

Abstract

This disclosure provides a filter membrane, a filter device, and a method for manufacturing the filter membrane. The filter membrane of this disclosure includes: a mesh structure made of stainless steel, the mesh structure having a pore size of less than 10 μm and having microstructures on its surface; and a modified layer comprising an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound, disposed on the mesh structure, the modified layer at least partially not covering the microstructures of the mesh structure.

Description

Technical Field

[0001] This disclosure relates to a filter membrane, a filter device, and a method for manufacturing a filter membrane, and more specifically, to a filter membrane, a filter device, and a method for manufacturing a filter membrane for filtering emulsions containing particulates. Background Technology

[0002] In semiconductor manufacturing, processes such as cutting, grinding, and polishing are frequently required to bring silicon carbide (SiC) substrates to the desired dimensions. The waste generated after these processes typically contains large amounts of valuable silicon carbide and diamond powder; however, currently, most of this waste is disposed of through landfill after processing. With increasing awareness of renewable energy and environmental protection, improving the recycling rate of this waste remains a crucial issue.

[0003] The current method for recycling silicon carbide waste typically involves first dispersing the waste into an emulsion containing both an oil and an aqueous phase. Separating agents are used to separate the silicon carbide in the aqueous phase and the diamond powder in the oil phase. Next, the emulsion is shaken and mixed to separate the layers, then demulsified using methods such as ultrasonic waves, and finally, a filtration membrane is used to recover the microparticles contained in the emulsion.

[0004] However, the demulsification process of the emulsions mentioned above usually requires pressurization, heating, or the use of chemicals to effectively demulsify the particulate-containing emulsions. This results in complex processes or potential environmental pollution from the use of chemicals. Furthermore, without effective demulsification, the separating agent cannot be well recovered. Additionally, existing filter membranes typically use organic polymers such as melamine sponge, nylon, and cellulose as substrates. However, these organic polymer membranes have weak mechanical strength, are difficult to etch, and have poor durability. On the other hand, organic polymer membranes are mostly three-dimensional pores with large pore sizes, requiring the formation of a filter cake during filtration to filter out particulates. However, once clogging reaches a certain level, filtration cannot continue. While smaller three-dimensional pores can effectively improve filtration efficiency, they also lead to rapid filter cake formation, resulting in reduced membrane flux. Therefore, existing filter membranes still have the problem of not being able to effectively filter particulates. Therefore, there is an urgent need for a filter membrane that features a simple filtration process, high particulate recovery rate, and excellent durability. Summary of the Invention

[0005] The purpose of this disclosure is to provide a filter membrane, a filter device, and a method for manufacturing the filter membrane that can be demulsified at room temperature, has a high recovery rate of particulate matter, and is durable.

[0006] A filter membrane includes: a mesh structure made of stainless steel, the mesh structure having a pore size of less than 10 μm and having microstructures on its surface; and a modification layer comprising an alkoxysilane compound, a halogen-based silane compound, or a polyalkylsiloxane compound disposed on the mesh structure, the modification layer not at least partially covering the microstructures of the mesh structure.

[0007] A filtration device comprising the filter membrane described above.

[0008] A method for manufacturing a filter membrane includes: (a) etching a mesh structure made of stainless steel to form microstructures on the surface of the mesh structure, wherein the pore size of the mesh structure is less than 10 μm; (b) dissolving a modifier including an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound in a first solvent to obtain a modified solution; and (c) coating the modified solution onto the etched mesh structure to form a modified layer, wherein the modified layer at least partially does not cover the microstructures of the mesh structure.

[0009] According to the filter membrane disclosed herein, since the mesh structure uses a stainless steel mesh material with a relatively small pore size as the substrate, it has good durability and can be etched compared to materials such as organic polymer membranes. Furthermore, it exhibits a better particle recovery rate compared to large-pore polymer materials. Moreover, the filter membrane of this disclosure forms a modified layer containing a specific material on the etched mesh structure, the substrate has rigidity and durability, and the combination with a thin modified layer of a specific thickness range results in excellent hydrophobicity. Therefore, the filter membrane of this disclosure can achieve demulsification at room temperature, high particle recovery rate, and excellent durability.

[0010] To make the above and other objects, features and advantages of this disclosure more apparent and understandable, embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0011] Figure 1 A flowchart showing a method for preparing a filter membrane according to the present disclosure is shown.

[0012] Figure 2 The images shown are from a scanning electron microscope (SEM) based on the filter membranes after different etching times, where (A) and (B) are images after 30 seconds of etching; (C) and (D) are images after 1 minute of etching; and (E) and (F) are images after 3 minutes of etching.

[0013] Figure 3 The images show SEM images of modified layers formed using different coating processes according to this disclosure.

[0014] Figure 4 shows SEM images and graphs of filter membranes prepared according to different concentrations of modifiers of this disclosure, wherein... Figure 4A SEM image of a filter membrane prepared using a 60 mM modifier concentration; Figure 4B A graph showing the scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) analysis of a filter membrane prepared using a 60 mM modifier concentration. Figure 4C SEM image of a filter membrane prepared using a 10 mM modifier concentration.

[0015] Figure 5 A graph showing the contact angle of the filter membranes to water or to oil according to the various embodiments and comparative examples.

[0016] Figure 6 This shows a SEM image of a filter membrane prepared according to the method for preparing a filter membrane according to the present disclosure.

[0017] Figure 7 The images shown are microscopic images of the emulsion before and after filtration using the filter membrane of this disclosure, wherein (A) is an image of the emulsion before filtration; (B) is an image of the filtrate after filtration; and (C) is an image of the filter cake after filtration.

[0018] Explanation of reference numerals in the attached figures

[0019] S110~S140: Steps;

[0020] Biological material storage: None Detailed Implementation

[0021] This disclosure can be understood from the various forms of disclosure, embodiments, and related descriptions of the tables listed below. Unless otherwise defined herein, the terms used in connection with this disclosure (including technical and scientific terms) should have the meanings understood by one of ordinary skill in the art to which this disclosure pertains. Furthermore, it should be understood that, unless otherwise specified in the definitions provided herein, in the event of any potential ambiguity, the definition of a term should be consistent with such commonly used terms (such as those defined in a dictionary). It will be further understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0022] It is important to note that, unless explicitly stated otherwise, the singular forms “a,” “an,” and “the” used in the specification or claims also include plural representations. Therefore, unless the context otherwise requires, singular terms should include plurals and plural terms should include singulars.

[0023] The following provides a detailed description of the filter membrane, filter device, and method for manufacturing the filter membrane disclosed herein.

[0024] In one embodiment of this disclosure, a filter membrane is provided, comprising a mesh structure and a modified layer. The mesh structure is made of stainless steel, has a pore size of less than 10 μm, and has microstructures on its surface. The modified layer may be composed of alkoxysilane compounds, halogenated silane compounds, or polyalkylsiloxane compounds, disposed on the mesh structure, and the modified layer at least partially does not cover the microstructures of the mesh structure. Using the filter membrane of this disclosure allows for demulsification at room temperature, high particle recovery rate, effective oil-water separation, and excellent durability.

[0025] In one embodiment of this disclosure, the mesh structure can use stainless steel as the mesh substrate of the filter membrane. The pore size of the stainless steel mesh can be less than 10 μm, for example, pore sizes of about 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 1 μm to 9 μm, 2 μm to 7 μm, or 3 μm to 5 μm. By using the aforementioned pore size of the stainless steel mesh, particles in the emulsion can be effectively filtered out. Furthermore, when using stainless steel, etching and other processes can be effectively performed to obtain the desired recessed microstructures on its surface. Specifically, the surface of the mesh structure has microstructures, which can be, for example, multiple pits, formed by etching or other methods, but are not limited to this; any method that effectively forms microstructures on a stainless steel mesh is acceptable. In some embodiments of this disclosure, the diameter of the plurality of recesses can be between 0.2 and 3 μm, and the depth of the recesses can be between 10 and 300 nm, but is not limited thereto. For example, the recess diameter can be, for example, 0.3 μm, 0.6 μm, 1.0 μm, 1.3 μm, 1.6 μm, 2.0 μm, 2.3 μm, 2.6 μm, etc., and the recess depth can be, for example, about 25 nm, 50 nm, 75 nm, 100 nm, 125 nm, 150 nm, 170 nm, 200 nm, 225 nm, 250 nm, 275 nm, etc. By forming such a microstructure on the mesh structure, the contact angle of the water droplet can be effectively improved, thereby improving the hydrophobic properties. Details of the method for measuring the water contact angle are described in the following embodiments.

[0026] In one embodiment of this disclosure, the modified layer comprises an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound, disposed on the network structure. By applying a modifier comprising an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound onto the etched network structure, a modified layer is formed on the network structure, thereby improving the oleophilic and hydrophobic properties. The modified layer of this disclosure may be a product formed from a modifier comprising an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound.

[0027] In one embodiment of this disclosure, the alkoxysilane compound and halogenated silane compound in the modifier may also be referred to as a "specific silane compound". The alkoxysilane compound may be a silane compound having an alkoxy group, and the halogenated silane compound may be a silane compound having a halogenated group. In addition to the aforementioned alkoxy or halogenated groups, the alkoxy or halogenated compound may contain one or more other functional groups. Furthermore, the alkoxy or halogenated group may contain only one or more, and in the case of multiple alkoxy or halogenated groups, these groups may be the same or different.

[0028] In one embodiment of this disclosure, the specific silane compound may be an alkoxysilane compound. Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, and isopropoxy. Furthermore, the alkoxysilane compound may have at least one functional group containing an alkyl group having 8 to 20 carbon atoms. Alkyl functional groups may be, for example, alkyl groups having 10 to 20 carbon atoms, 12 to 18 carbon atoms, or 15 to 18 carbon atoms, specifically, linear or branched alkyl groups such as octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl.

[0029] Specifically, the aforementioned alkoxysilane compounds may be, for example, octyltrimethoxysilane, nonyltrimethoxysilane, decyltrimethoxysilane, undecyltrimethoxysilane, dodecyltrimethoxysilane, tridecyltrimethoxysilane, tetradecyltrimethoxysilane, pentadecyltrimethoxysilane, hexadecyltrimethoxysilane, heptadecanyltrimethoxysilane, octadecyltrimethoxysilane (ODTMS), octadecyltriethoxysilane, nonadecanyltrimethoxysilane, or eicosyltrimethoxysilane, etc.

[0030] In one embodiment of this disclosure, the specific silane compound may be a halogenated silane compound. The halogen group may be, for example, fluorinated, chlorolated, or bromine-based. Furthermore, the halogenated silane compound may have at least one functional group containing an alkyl group having 8 to 20 carbon atoms. The alkyl functional group may be, for example, a linear or branched alkyl group having 10 to 18 carbon atoms, 12 to 18 carbon atoms, or 15 to 18 carbon atoms, specifically, linear or branched alkyl groups such as octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl.

[0031] Specifically, the aforementioned halogenated silane compounds may be, for example, octyltrifluorosilane, octyltrichlorosilane, nonyltrifluorosilane, nonyltrichlorosilane, decyltrifluorosilane, decyltrichlorosilane, undecyltrifluorosilane, undecyltrichlorosilane, dodecyltrifluorosilane, dodecyltrichlorosilane, tridecyltrifluorosilane, tridecyltrichlorosilane, pentadecyltrifluorosilane, pentadecyltrichlorosilane, hexadecyltrifluorosilane, hexadecyltrichlorosilane, heptadecanyltrifluorosilane, heptadecanyltrichlorosilane, octadecyltrifluorosilane, octadecyltrichlorosilane (ODTCS), nonadecanyltrifluorosilane, nonadecanyltrichlorosilane, eicosyltrifluorosilane, eicosyltrichlorosilane, etc.

[0032] In another embodiment of this disclosure, the polyalkylsiloxane compound in the modifier may be an alkyl group having 1 to 8 carbon atoms on the silicon atom. The silane may be, for example, a straight-chain or branched alkyl group such as methyl, ethyl, propyl, butyl, pentyl, or hexyl. Specifically, the aforementioned polyalkylsiloxane compound may be, for example, polydimethylsiloxane (PDMS).

[0033] Modifiers can be in the form of a modified solution dissolved in a solvent. For example, when a modifier is in the form of a modified solution, the inclusion of a solvent makes its application easier. The solvent can function to dissolve the components contained in the modifier, or it can function as a dispersion medium. Examples of solvents include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, propyl acetate, and butyl acetate; aliphatic hydrocarbons such as n-hexane and heptane; and ethers such as tetrahydrofuran, dialkylene, diethyl ether, and dibutyl ether. Only one of these solvents can be used, or two or more can be used in combination.

[0034] In one embodiment of this disclosure, the modified solution can be applied by solvent casting, spray coating, dip coating, etc. For example, a coating method in which the modified solution does not cover the microstructure of the network structure can be used. In some embodiments of this disclosure, the thickness of the modified layer after curing the modified solution on the network structure can be from 100 nm to 400 nm. The thickness of the modified layer can be, for example, about 110 nm, 130 nm, 150 nm, 170 nm, 190 nm, 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, 320 nm, 350 nm, 380 nm, 150 nm~350 nm, or 200 nm~300 nm. If the thickness of the modified layer is too thick, the microstructure becomes relatively flat, thus reducing the oleophilic and hydrophobic effect; if the thickness is too thin, the coating is insufficient, thus reducing the oleophilic and hydrophobic effect.

[0035] In one embodiment of this disclosure, the modified layer of this disclosure at least partially does not cover the microstructure of the network structure, for example, at least 50%, 60%, 70%, 80%, 50%~80%, or 60%~70% of the microstructure is not covered. According to one embodiment of this disclosure, the water contact angle of the modified layer of this disclosure can be in the range of 120 degrees to 150 degrees, but is not limited thereto; for example, it can be 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 125 degrees~145 degrees. In the filter membrane of this disclosure, by making the water contact angle of the modified layer 120 degrees or more, the filter membrane can be endowed with good hydrophobicity, thereby achieving excellent demulsification effect. If the water contact angle of the modified layer is less than 120 degrees, there may be insufficient hydrophobicity, which may prevent the emulsion from being fully demulsified, and after the emulsion passes through the filter membrane, there may be oil and water coexisting in the lower layer.

[0036] By using the filter membrane described above, it is possible to demulsify emulsions containing particulates (such as emulsions generated during the waste treatment process of silicon carbide substrates) even at room temperature, achieve high particulate recovery rate, and have good durability.

[0037] The filter membrane disclosed herein can be manufactured by the following method. That is, as... Figure 1 As shown, the method for manufacturing the filter membrane disclosed herein includes: etching a mesh structure made of stainless steel to form microstructures on the surface of the mesh structure (S110), wherein the pore size of the mesh structure is less than 10 μm; dissolving a modifier including an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound in a first solvent to obtain a modified solution (S120); coating the modified solution onto the etched mesh structure, wherein the modified layer at least partially does not cover the microstructures of the mesh structure (S130); and baking the obtained filter membrane under a baking condition (S140).

[0038] According to one embodiment of this disclosure, in step S110, a mesh structure made of stainless steel is etched. The selection of the stainless steel mesh as the substrate and the details of its microstructure can be found in the description above. Before etching the mesh structure, the stainless steel mesh may be pretreated; specifically, the stainless steel mesh may be cleaned with deionized water, acetone, etc., and then dried to remove organic or inorganic contaminants from its surface. In a specific embodiment of this disclosure, the stainless steel mesh is wet-etched using an etching solution, for example, static wet etching, to form a microstructure on its surface. The etching solution may be an acidic etching solution, such as, but not limited to, a mixture of ferric chloride (FeCl3) and hydrogen peroxide / hydrochloric acid, the proportion and concentration of which can be appropriately set as needed. In step S110, the etching time can be any time sufficient to form the microstructure, which can be from 15 seconds to 5 minutes, for example, 30 seconds, 1 minute, 1.5 minutes, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes, etc. By adjusting the etching time within the above range, the water contact angle of the modified layer in the obtained filter screen can be within the range desired by this disclosure.

[0039] According to one embodiment of this disclosure, in step S120, a modifier including an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound is dissolved in a first solvent to obtain a modified solution. Details of the alkoxysilane compound, halogenated silane compound, or polyalkylsiloxane compound can be found in the description above. By preparing the modifier as a modified solution, the modifier can be easily and uniformly coated onto the network structure. In one embodiment of this disclosure, the first solvent can be an organic solvent capable of dissolving a specific silane compound and miscible with water. Examples of first solvents include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, propyl acetate, and butyl acetate; aliphatic hydrocarbons such as n-hexane and heptane; and ethers such as tetrahydrofuran, dialkylene, diethyl ether, and dibutyl ether. Only one of these solvents may be used, or two or more may be used in combination. In order to ensure that the modifier in the modification solution is well coated onto the network structure, the concentration of the modifier in the modification solution can be, for example, from 10 mM to 100 mM, but is not limited thereto. For example, about 20 mM, 40 mM, 60 mM, 80 mM, 20 mM~80 mM, or 40 mM~60 mM, etc. When using the above concentration range, the thickness required by the present disclosure can be obtained when the modifier is coated onto the network structure, and the cavities of the network structure can be prevented from being blocked.

[0040] In step S130, the modified solution is coated onto the mesh structure to form a modified layer film. In this coating step, for example, the modified solution can be coated onto the mesh structure using solvent casting, spray coating, or dip coating to form the modified layer film. From the viewpoint of easily forming a coating film of the desired thickness and morphology, dip coating can be used in the coating step. In a specific embodiment of this disclosure, the immersion time of the etched mesh structure in the modified solution can be appropriately adjusted according to the concentration of the modifier, etc., but can be, for example, about 5 to 20 minutes, such as, but not limited to, 5 minutes, 7 minutes, 10 minutes, 13 minutes, 15 minutes, 18 minutes, etc.

[0041] According to a specific embodiment of this disclosure, step S130 may further include, after the modified solution is coated onto the mesh structure, a step of further immersing the mesh structure with the modified layer into a second solvent. The second solvent may be, for example, a mixture of alcohol and water. The alcohol may be, for example, a monohydric alcohol such as methanol, ethanol, propanol, 2-propanol, 1-butanol, or a dihydric alcohol such as ethylene glycol, propylene glycol, or butanediol, wherein one or more alcohols may be used. The content of the aforementioned alcohol may be, for example, 10-50% by mass or 20-40% by mass. Furthermore, the immersion time in the second solvent may be appropriately adjusted according to the concentration of the alcohol, but may be, for example, within approximately 60 seconds, such as, but not limited to, 50 seconds, 40 seconds, 30 seconds, 20 seconds, or 10 seconds. Through the above process, the uniformity of the formed modified layer can be improved, and the problem of clogging of the mesh structure's cavities can be avoided.

[0042] In step S140, the obtained filter membrane is baked under baking conditions. The temperature under these baking conditions can be in the range of 300°C to 100°C. The baking time can be set to a time sufficient to allow the modified layer to cure well, for example, it can be set appropriately between 1 hour and 6 hours.

[0043] The following embodiments are provided to assist those skilled in the art in implementing this disclosure. However, these embodiments should not be considered as limitations of this disclosure, as modifications and variations made to the embodiments discussed herein by those skilled in the art to which this disclosure pertains without departing from the spirit or scope of this disclosure are still within the scope of this disclosure.

[0044] Example

[0045] (1) Evaluation method

[0046] (1-1) Microscopic observation

[0047] 1. Scanning electron microscope

[0048] Scanning electron microscopy (SEM) is used to extract images of the surface or cross-section of the filter membrane to confirm its morphological characterization. Alternatively, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) can be used to observe the elemental distribution of the filter membrane. The SEM used in the embodiments of this disclosure is a JEOL JSM-6500F.

[0049] 2. Images of the emulsion before and after filtration were extracted using an optical microscope to confirm the filtration status of the emulsion. The emulsion, filtrate, and filter cake were observed using an optical microscope from the brand SOPTOP, model RX50M.

[0050] (1-2) Measurement of water contact angle

[0051] Using a First Ten Ångstrom surface tension meter, model FTA 125, the filter membrane sample was fixed on a glass slide. A 3 μL drop of water or decane was dropped onto the filter membrane sample, and after 5 seconds, the contact angle of the filter membrane relative to water or oil was recorded. Each sample was measured 5 times at different positions and the average was obtained.

[0052] (1-3) Measurement of oil-water separation rate

[0053] The water content in the filtrate after filtration through each membrane sample was determined using a Karl-Fischer titrator (SI Analytics, 7500KF trace). Before measurement, the system stability was confirmed with a standard containing 0.1% water, and the experiment was conducted in accordance with the manufacturer's operating manual. The oil-water separation rate was calculated using the following formula.

[0054] Oil-water separation rate (%) = (Water content of emulsion sample - Water content of filtrate after filtration) / Water content of emulsion sample × 100

[0055] (1-4) Definition of surface energy

[0056] The surface energy of each modifier can be referenced from the Sci-Finder online database.

[0057] (2) Preparation of filter membrane

[0058] (2-1) Confirmation of etching conditions

[0059] Using a 2800-mesh stainless steel mesh (approximately 4-5 μm aperture) as the main substrate, after cleaning with acetone and drying, the stainless steel mesh is immersed in an etching solution for static etching for 30 seconds, 1 minute, or 3 minutes, followed by rinsing with clean water. The etching solution is a mixture prepared using 1M FeCl3, 12M hydrochloric acid (HCl), and 5% H2O2 in a volume ratio of 20:1:1.

[0060] Next, polydimethylsiloxane (PDMS) was used as a modifier to test the relationship between etching time and water contact angle, such as... Figure 2 As shown, (A) and (B) are images after 30 seconds of etching; (C) and (D) are images after 1 minute of etching; and (E) and (F) are images after 3 minutes of etching. The 30-second etching time shows that the microstructure has not yet fully formed. The water contact angle was measured, and it was found that the water contact angle after 30 seconds of etching was 125 degrees, while the water contact angles after 1 minute and 3 minutes of etching could be increased to 130 and 137 degrees, respectively. Therefore, the filtration membrane was prepared using an etching time of 3 minutes.

[0061] (2-2) Confirmation of the modification process

[0062] Process A: Impregnation method

[0063] The modifier octadecylchlorosilane was dissolved in tetrahydrofuran (THF) to prepare a 60 mM modification solution. The etched stainless steel mesh was immersed in the modification solution containing the modifier for 3 minutes. After removal, the modification solution was allowed to evaporate completely and then dried at 60°C for 4 hours.

[0064] Process B: Solvent-inducible phase transfer method

[0065] The modifier octadecylchlorosilane was dissolved in THF to prepare a 60 mM modification solution. Next, an aqueous solution containing 20% ​​ethanol was prepared. The etched stainless steel mesh was immersed in the modification solution containing the modifier for 3 minutes. After removing the stainless steel mesh from the modification solution, it was quickly immersed in the 20% ethanol aqueous solution for 30 seconds, and then dried at 60°C for 4 hours.

[0066] like Figure 3As shown, (A) is a filter membrane prepared by the above-mentioned process A: impregnation process, and (B) is a filter membrane prepared by the above-mentioned process B: solvent-induced phase transfer process. It is clearly visible from the images that, when using process A, the microstructure of the mesh surface is less noticeable and the pore size is smaller, with an average pore size of approximately 0.3 to 0.5 μm. A significant portion of the microstructure is covered by the modified layer, resulting in a large proportion of the modified layer exhibiting a filamentous structure in the images. However, when using process B, the surface microstructure shows obvious pits and depressions, with an average pore size of approximately 0.8 to 1.2 μm, indicating that most of the microstructure on the stainless steel mesh is not covered by the modified layer.

[0067] (2-3) Confirmation of Modification Concentration

[0068] The modifier, octadecyltrichlorosilane (ODTCS), was dissolved in tetrahydrofuran (THF) to prepare 10 mM or 60 mM modified solutions, and the above-described process B was performed to obtain filter membranes made with different concentrations of modifier.

[0069] like Figure 4A , Figure 4B and Figure 4C As shown, where Figure 4A SEM image of a filter membrane prepared using a 60 mM modifier concentration; Figure 4B Elemental analysis results of SEM-EDS for filter membranes prepared using a 60 mM modifier concentration; Figure 4C SEM images of filter membranes prepared using a 10 mM modifier concentration. Based on Figure 4A It is known that, using a modifier concentration of 60 mM, a modified layer with a thickness of over 200 nm can be obtained, while... Figure 4C It is known that even with a modifier concentration of 10 mM, a modified layer with a thickness of approximately 140 nm or more can be obtained, demonstrating that even with a lower modifier concentration, the desired modified layer thickness can be sufficiently formed. Furthermore, based on... Figure 4B As can be seen from the elemental analysis, there are no chlorine atoms in the modifier, because the chlorine atoms in octadecyltrichlorosilane are removed during the dehydration reaction in the process.

[0070] (3) Preparation of the Implementation Example

[0071] Besides adjusting the types of modifiers, each embodiment was prepared based on the above process. The types of modifiers used in each embodiment, or the absence of modifiers, are shown in Table 1 below. Furthermore, the stainless steel mesh used in Examples 1-6 was prepared from etched stainless steel mesh, and the modifier concentration in Examples 1-6 was 0.3 wt%.

[0072] Table 1

[0073]

[0074] (4) Evaluation of the effectiveness of the filtration membrane

[0075] (4-1) Results of contact angles with water or oil

[0076] like Figure 5 Examples 1-6 show the contact angles with water and oil after etching followed by either process A or process B, and after treatment with different modifiers. In Examples 1, 2, and 6, the etched stainless steel mesh, after treatment with either process A or process B, showed a significant increase in water contact angle and a lower oil contact angle, indicating a significant improvement in hydrophobicity and good oleophilic properties. After process B treatment, the variability in the measured water contact angle was relatively small, indicating that process B helps improve coating uniformity. The results of Example 3 show little change in the water contact angle, but after process B treatment, the variability in the water contact angle decreased, indicating that the filter membrane produced by process B performs more stably. The results of Example 4 show that the modification treatment significantly improves hydrophobicity and also has good oleophilic properties; after process B treatment, the variability in the measured water contact angle is relatively small. The results of Example 5 show that although polystyrene is a hydrophobic polymer, its hydrophobic effect is poor, and it also has high oleophobicity, indicating that this process is not suitable for certain organic polymers.

[0077] (4-2) Morphology of the filter membrane

[0078] Image observation of Example 3 was performed using a scanning electron microscope, and the results are as follows: Figure 6 In (A), it can be confirmed that the formation of the modified layer does not affect the pore size of the network structure, that is, it still has a pore size of about 4 to 5 μm, and therefore does not affect the filtration effect of the filter membrane. Furthermore, since... Figure 6 (B) The image also clearly shows that the modified layer does not cover the microstructure formed on the surface of the mesh structure, so the clear recessed microstructure is still maintained on the surface of the filter membrane.

[0079] (4-3) Results of oil-water separation rate

[0080] A standard Pickering emulsion was prepared. Specifically, approximately 3 wt% of a microparticle mixture of silicon carbide powder and diamond powder was mixed with water, and an appropriate amount of decane was added as an oil phase solvent. The mixture was shaken and stirred to emulsify, forming a Pickering emulsion containing microparticles. The filter membranes of each example and comparative example were installed in a funnel connected to a conical flask, and then the above emulsion was poured in for filtration to obtain a filter cake and a filtrate. The water content of each filtrate was determined as described above, and the oil-water separation rate of each example and comparative example was calculated according to the above formula. The results are shown in Table 2 below.

[0081] Table 2

[0082]

[0083] like Figure 7 The images are magnified 20 times under an optical microscope. (A) is an image of the emulsion before filtration; (B) is an image of the filtrate after filtration using Example 1; and (C) is an image of the filter cake after filtration using Example 1. Based on... Figure 7 As can be seen from the images, the filtrate after filtration is a clear solution, without the presence of particles or droplets found in the emulsion before filtration. In contrast, the filter cake image shows clearly stacked particle clumps with dispersed particles around them, indicating that the filter membrane of this disclosure has excellent particle filtration efficiency. Furthermore, as shown in Table 2, Examples 1, 2, and 6 exhibit extremely high oil-water separation rates, demonstrating excellent hydrophobic and oleophilic effects.

[0084] The filter membrane disclosed herein exhibits excellent durability due to the use of stainless steel mesh. Unlike organic polymer substrates, it is easier to form microstructures on stainless steel, allowing for demulsification even at room temperature and effectively enhancing its hydrophobic and oleophilic properties. Furthermore, the small pore size of the stainless steel mesh effectively filters out particulate matter. Therefore, the filter membrane disclosed herein can be practically installed in filtration devices such as wastewater treatment systems, demonstrating excellent applicability.

Claims

1. A filter membrane, comprising: A mesh structure, the material of which includes stainless steel, has a pore size of less than 10 μm and has microstructures on its surface; as well as A modified layer, comprising an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound, is disposed on the network structure, wherein the modified layer at least partially does not cover the microstructure of the network structure.

2. The filter membrane according to claim 1, wherein the alkoxysilane compound is a methoxysilane compound.

3. The filter membrane according to claim 1, wherein the halogenated silane compound is a chlorosilane compound.

4. The filter membrane according to claim 1, wherein the polyalkylsiloxane compound is a polydimethylsiloxane compound.

5. The filter membrane according to any one of claims 1 to 3, wherein the alkoxysilane compound or halogen-based silane compound has a functional group containing an alkyl group having 8 to 18 carbon atoms.

6. The filter membrane according to claim 1, wherein the microstructure comprises a plurality of cavities, the diameter of the plurality of cavities being between 0.2 and 3 μm, and the depth of the plurality of cavities being between 10 and 300 nm.

7. The filter membrane according to claim 1, wherein the thickness of the modified layer is 100 to 400 nm.

8. A filtration device comprising a filter membrane as claimed in any one of claims 1 to 7.

9. A method for manufacturing a filter membrane, comprising: (a) Etching a mesh structure, including stainless steel, to form a microstructure on the surface of the mesh structure, wherein the pore size of the mesh structure is less than 10 μm; (b) Dissolving a modifier, including an alkoxysilane compound, a halogenated silane compound, or a polyalkylsiloxane compound, in a first solvent to obtain a modified solution; as well as (c) The modified solution is applied to the etched mesh structure to form a modified layer, wherein the modified layer at least partially does not cover the microstructure of the mesh structure.

10. The method for manufacturing a filter membrane according to claim 9, wherein the alkoxysilane compound is a methoxysilane compound.

11. The method for manufacturing a filter membrane according to claim 9, wherein the halogenated silane compound is a chlorosilane compound.

12. The method for manufacturing a filter membrane according to claim 9, wherein the polyalkylsiloxane compound is a polydimethylsiloxane compound.

13. The method of manufacturing a filter membrane according to any one of claims 9 to 11, wherein the alkoxysilane compound or halogen-based silane compound has a functional group containing an alkyl group having 8 to 18 carbon atoms.

14. The method for manufacturing a filter membrane according to claim 9, wherein the first solvent is an organic solvent capable of dissolving the silane compound and miscible with water.

15. The method for manufacturing a filter membrane according to claim 9, further comprising (d) baking the filter membrane obtained in step (c) under baking conditions.

16. The method for manufacturing a filter membrane according to claim 15, wherein the baking conditions are a baking temperature between 60 and 200°C and a baking time between 2 and 24 hours.

17. The method for manufacturing a filter membrane according to claim 9, wherein step (c) further comprises: Prepare a second solvent and immerse the network structure with the modified layer into the second solvent, wherein the second solvent is a different solvent from the first solvent.

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