Antibacterial filtering membrane for treating cutting fluid and preparation method of antibacterial filtering membrane

Abstract

The invention relates to the field of filtering membranes, in particular to an antibacterial filtering membrane for treating cutting fluid and a preparation method of the antibacterial filtering membrane, and aims at solving the problems that an existing filtering membrane for the cutting fluid is poor in antibacterial performance and insufficient in mechanical strength. According to the preparation method, copper nano particles and silver nano particles with broad-spectrum antibacterial effects are combined with high-strength and high-conductivity graphene, so that the prepared antibacterial filtering membrane has excellent antibacterial performance, growth of microorganisms can be effectively inhibited, small particles and microorganisms in the cutting fluid can be effectively removed, and the antibacterial filtering membrane has a good antibacterial effect on the cutting fluid. The antibacterial filter membrane has the advantages of high mechanical strength, high chemical stability, adaptability to complex industrial environments, simplicity in preparation process and suitableness for industrial production, and provides reliable technical support for management and cyclic utilization of the cutting fluid.

Description

Technical Field

[0001] The invention relates to the field of filter membranes, and in particular to an antibacterial filter membrane for treating cutting fluid and a preparation method thereof. Background Art

[0002] In the metal processing industry, cutting fluid is an industrial liquid used to cool and lubricate cutting tools and workpieces, reducing wear, extending tool life, and improving processing accuracy. There are many types of cutting fluids, which usually contain water, oils, additives and other ingredients, which can effectively control temperature and prevent corrosion of mechanical equipment. However, as the cutting fluid circulates continuously during use, it gradually becomes a breeding ground for bacteria and other microorganisms. The reproduction of microorganisms not only causes the deterioration of the cutting fluid, but also causes unpleasant odors, reduces the performance of the cutting fluid, and even damages the processing equipment. These problems lead to frequent replacement of cutting fluids, increased production costs and environmental pollution.

[0003] At present, the common methods to solve the microbial contamination of cutting fluid mainly include adding chemical fungicides and physical filtration. However, chemical fungicides are prone to cause secondary pollution to the environment and may also have adverse effects on the health of operators. Although physical filtration technology can remove particulate impurities in cutting fluid, most existing filter membranes lack sufficient antibacterial function and cannot effectively inhibit the growth of microorganisms, making it difficult to significantly extend the service life of cutting fluid. In addition, the mechanical strength of traditional filter membranes is often insufficient, which affects their widespread application in the industrial field.

[0004] How to improve the poor antibacterial performance and insufficient mechanical strength of the existing filter membranes for cutting fluid is the key to the present invention. Therefore, an antibacterial filter membrane for treating cutting fluid and a preparation method thereof are urgently needed to solve the above problems. Summary of the invention

[0005] In order to overcome the above-mentioned technical problems, the purpose of the present invention is to provide an antibacterial filter membrane for treating cutting fluid and a preparation method thereof, and to combine copper nanoparticles and silver nanoparticles with broad-spectrum antibacterial effects with high-strength and high-conductivity graphene to prepare an antibacterial filter membrane material, thereby solving the problems of poor antibacterial performance and insufficient mechanical strength of existing filter membranes for cutting fluid.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] An antibacterial filter membrane for treating cutting fluid comprises the following components in parts by weight:

[0008] 90-98 parts of base film material, 0.5-5 parts of copper nanoparticles, 0.1-3 parts of silver nanoparticles and 0.5-2 parts of graphene sheets;

[0009] The base film material is one of polyvinylidene fluoride, polyether sulfone and polypropylene;

[0010] The average particle size of the copper nanoparticles is 10-50 nanometers;

[0011] The average particle size of the silver nanoparticles is 5-20 nanometers;

[0012] The thickness of the graphene sheet is less than 10 nanometers.

[0013] As a further solution of the present invention: the copper nanoparticles are prepared by the following steps:

[0014] Step a1: dissolving a copper salt in deionized water to obtain a copper salt solution with a molar concentration of 0.01 mol / L;

[0015] Step a2: Add a reducing agent to the copper salt solution, and stir the reaction at a reaction temperature of 80° C. for 30 minutes, then centrifuge and separate, wash the precipitate with deionized water for 3 times, and then dry to obtain copper nanoparticles.

[0016] As a further solution of the present invention: the copper salt is copper nitrate; the reducing agent is ascorbic acid; and the molar ratio of the copper salt to the reducing agent is 1:5.

[0017] As a further solution of the present invention: the silver nanoparticles are prepared by the following steps:

[0018] Step b1: dissolving silver salt in deionized water to obtain a silver salt solution with a molar concentration of 0.005 mol / L;

[0019] Step b2: Add a reducing agent to the silver salt solution, and stir the reaction at a reaction temperature of 70° C. for 80 minutes, then centrifuge and wash the precipitate with deionized water for 3 times, and then dry to obtain silver nanoparticles.

[0020] As a further solution of the present invention: the silver salt is silver nitrate; the reducing agent is glucose; and the molar ratio of the silver salt to the reducing agent is 1:20.

[0021] As a further solution of the present invention: the graphene sheet is prepared by the following steps:

[0022] Graphite powder was added to a mixed acid of concentrated sulfuric acid and concentrated nitric acid, and the reaction was stirred for 30 minutes at a reaction temperature of 0°C. Potassium permanganate was then added and the reaction was continued to stir for 2 hours. The temperature was then raised and the reaction was continued to stir for 2 hours at a reaction temperature of 40°C. The temperature was then raised and the reaction was continued to stir for 1.5 hours at a reaction temperature of 98°C. The mixture was then added to hydrogen peroxide and allowed to stand for 12 hours. The mixture was then centrifuged and the precipitate was washed 3 times with hydrochloric acid solution and deionized water, and then dried to obtain a graphene sheet.

[0023] As a further solution of the present invention: the usage ratio of the graphite powder, concentrated sulfuric acid, concentrated nitric acid, potassium permanganate and hydrogen peroxide is 2g:70mL:22mL:12g:300mL.

[0024] As a further solution of the present invention: the mass fraction of the concentrated sulfuric acid is 98%, the mass fraction of the concentrated nitric acid is 68%, the mass fraction of the hydrogen peroxide is 7%, and the mass fraction of the hydrochloric acid solution is 5%.

[0025] As a further solution of the present invention: a method for preparing an antibacterial filtration membrane for treating cutting fluid comprises the following steps:

[0026] Step 1: Dispersing the base film material, copper nanoparticles, silver nanoparticles and graphene sheets in a polyvinyl pyrrolidone solution respectively, and then subjecting the solution to ultrasonic treatment to obtain uniformly dispersed base film material solution, copper nanoparticle dispersion, silver nanoparticle dispersion and graphene sheet dispersion respectively;

[0027] Step 2: uniformly stirring the base film material solution, the copper nanoparticle dispersion, the silver nanoparticle dispersion and the graphene sheet dispersion to obtain a mixed solution; wherein the mass ratio of the base film material, the copper nanoparticles, the silver nanoparticles and the graphene sheet in the mixed solution is 90-98:0.5-5:0.1-3:0.5-2;

[0028] Step 3: evenly coating the blended solution on the substrate to form a coating film with a film thickness of 50-200 microns;

[0029] Step 4: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film;

[0030] Step 5: Immerse the gelled film in deionized water for curing, the water bath time is 0.5-2 hours, and a cured film is obtained;

[0031] Step 6: Dry the cured film at a drying temperature of 60-80° C. for 2-6 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

[0032] As a further solution of the present invention: the polyvinyl pyrrolidone solution is a polyvinyl pyrrolidone aqueous solution with a mass fraction of 5%.

[0033] As a further solution of the present invention: the mass ratio of the base film material to the polyvinyl pyrrolidone solution is 1:5.

[0034] As a further solution of the present invention: the mass ratio of the copper nanoparticles to the polyvinyl pyrrolidone solution is 1:5.

[0035] As a further solution of the present invention: the mass ratio of the silver nanoparticles to the polyvinyl pyrrolidone solution is 1:5.

[0036] As a further solution of the present invention: the mass ratio of the graphene sheet to the polyvinyl pyrrolidone solution is 1:5.

[0037] Beneficial effects of the present invention:

[0038] The invention discloses an antibacterial filter membrane for treating cutting fluid and a preparation method thereof. The method comprises the following steps: dispersing a base membrane material, copper nanoparticles, silver nanoparticles and graphene sheets in a polyvinyl pyrrolidone solution to obtain uniformly dispersed base membrane material solution, copper nanoparticle dispersion, silver nanoparticle dispersion and graphene sheet dispersion, then uniformly stirring the base membrane material solution, copper nanoparticle dispersion, silver nanoparticle dispersion and graphene sheet dispersion to obtain a mixed solution, then uniformly coating the mixed solution on a substrate to form a coating film, then placing the coating film at room temperature to obtain a gelled film, then immersing the gelled film in deionized water for curing to obtain a cured film, then drying the cured film to obtain an antibacterial filter membrane for treating cutting fluid.

[0039] The preparation method adds copper nanoparticles and silver nanoparticles to the base film material. The copper nanoparticles will undergo a chemical reaction in the presence of water and oxygen to generate active oxygen. The active oxygen has a strong redox effect and can attack the cell structure of bacteria and destroy the normal physiological function of bacteria. The positively charged copper ions can attract and combine with the negatively charged bacterial cell wall and cell membrane, thereby interfering with the integrity of the bacterial cell structure, causing the leakage of substances in the cells and ultimately causing the death of the bacteria, thereby achieving the purpose of inhibiting the proliferation of bacteria or directly killing bacteria. The silver nanoparticles will continuously release silver ions. The silver ions have an extremely small particle size and can freely enter the bacterial cell membrane at a very low concentration. After entering the bacterial cell membrane, the silver ions will quickly combine with the thiol groups on the bacterial cell membrane. The combination of the silver ions and the thiol groups will block the metabolic process of the bacteria. Therefore, the addition of copper nanoparticles and silver nanoparticles can give the filter membrane an excellent antibacterial effect, can significantly inhibit the reproduction of bacteria in the cutting fluid, and extend the service life of the cutting fluid. The preparation method also adds graphene sheets to the base membrane material. Graphene has excellent mechanical strength. Adding it to the filter membrane can enhance the overall strength of the filter membrane, making it more durable during use, not easy to break or damage, and help to extend the service life of the filter membrane. Moreover, the surface properties of graphene give it a lower surface energy, which not only makes it difficult for dirt and bacteria to adhere and accumulate on its surface, further improving its antibacterial properties, but also reduces the contamination of the filter membrane during use, maintains the permeability and filtration efficiency of the filter membrane, reduces the cleaning frequency and maintenance cost of the filter membrane, and prevents the erosion of corrosive media, thereby improving the chemical stability and durability of the filter membrane.

[0040] In summary, the antibacterial filter membrane for treating cutting fluid of the present invention has excellent antibacterial properties, can effectively inhibit the growth of microorganisms, and effectively remove tiny particles and microorganisms in the cutting fluid, thereby extending the service life of the cutting fluid. At the same time, it has high mechanical strength and chemical stability, and is adaptable to complex industrial environments. The preparation process of the antibacterial filter membrane is simple, and is suitable for industrial production, providing reliable technical support for the management and recycling of cutting fluids. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Embodiment 1:

[0043] This embodiment is a method for preparing an antibacterial filtration membrane for treating cutting fluid, comprising the following steps:

[0044] Step S1: dissolving copper nitrate in deionized water to obtain a copper salt solution with a molar concentration of 0.01 mol / L;

[0045] Step S2: adding ascorbic acid reducing agent to the copper salt solution, wherein the molar ratio of copper nitrate to ascorbic acid reducing agent is 1:5, and stirring the reaction at a reaction temperature of 80° C. for 30 minutes, followed by centrifugation, washing the precipitate with deionized water for 3 times, and then drying to obtain copper nanoparticles with an average particle size of 20 nanometers;

[0046] Step S3: dissolving silver nitrate in deionized water to obtain a silver salt solution with a molar concentration of 0.005 mol / L;

[0047] Step S4: adding glucose reducing agent to the silver salt solution, wherein the molar ratio of silver nitrate to glucose reducing agent is 1:20, and stirring the reaction at a reaction temperature of 70° C. for 80 minutes, followed by centrifugation, washing the precipitate with deionized water for 3 times, and then drying to obtain silver nanoparticles with an average particle size of 10 nanometers;

[0048] Step S5: adding 2 g of graphite powder to a mixed acid of 70 mL of 98% concentrated sulfuric acid and 22 mL of 68% concentrated nitric acid, stirring the mixture for 30 minutes at a reaction temperature of 0° C., then adding 12 g of potassium permanganate and stirring the mixture for 2 hours, then heating the mixture and stirring the mixture for 2 hours at a reaction temperature of 40° C., then heating the mixture and stirring the mixture for 1.5 hours at a reaction temperature of 98° C., then adding the mixture to 300 mL of 7% hydrogen peroxide and allowing the mixture to stand for 12 hours, then centrifuging the mixture, washing the mixture 3 times with a 5% hydrochloric acid solution and deionized water, and then drying the mixture to obtain a graphene sheet having a thickness of less than 5 nanometers;

[0049] Step S6: Dispersing polyvinylidene fluoride, copper nanoparticles, silver nanoparticles and graphene sheets in a polyvinyl pyrrolidone solution with a mass fraction of 5%, respectively, and then subjecting the solution to ultrasonic treatment to obtain uniformly dispersed base film material solution, copper nanoparticle dispersion, silver nanoparticle dispersion and graphene sheet dispersion, respectively; controlling the mass ratio of polyvinylidene fluoride to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of copper nanoparticles to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of silver nanoparticles to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of graphene sheets to polyvinyl pyrrolidone solution to be 1:5;

[0050] Step S7: stirring the base film material solution, the copper nanoparticle dispersion, the silver nanoparticle dispersion and the graphene sheet dispersion to obtain a mixed solution; wherein the mass ratio of polyvinylidene fluoride, copper nanoparticles, silver nanoparticles and graphene sheets in the mixed solution is 98:0.5:0.1:0.5;

[0051] Step S8: uniformly coating the blended solution on the substrate to form a coating film with a film thickness of 100 μm;

[0052] Step S9: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film;

[0053] Step S10: immersing the gelled film in deionized water for curing, the water bath time is 1 hour, and a cured film is obtained;

[0054] Step S11: drying the cured film at a drying temperature of 60° C. for 2 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

[0055] Embodiment 2:

[0056] This embodiment is a method for preparing an antibacterial filtration membrane for treating cutting fluid, comprising the following steps:

[0057] Step S1: dissolving copper nitrate in deionized water to obtain a copper salt solution with a molar concentration of 0.01 mol / L;

[0058] Step S2: adding ascorbic acid reducing agent to the copper salt solution, wherein the molar ratio of copper nitrate to ascorbic acid reducing agent is 1:5, and stirring the reaction at a reaction temperature of 80° C. for 30 minutes, followed by centrifugation, washing the precipitate with deionized water for 3 times, and then drying to obtain copper nanoparticles with an average particle size of 20 nanometers;

[0059] Step S3: dissolving silver nitrate in deionized water to obtain a silver salt solution with a molar concentration of 0.005 mol / L;

[0060] Step S4: adding glucose reducing agent to the silver salt solution, wherein the molar ratio of silver nitrate to glucose reducing agent is 1:20, and stirring the reaction at a reaction temperature of 70° C. for 80 minutes, followed by centrifugation, washing the precipitate with deionized water for 3 times, and then drying to obtain silver nanoparticles with an average particle size of 10 nanometers;

[0061] Step S5: adding 2 g of graphite powder to a mixed acid of 70 mL of 98% concentrated sulfuric acid and 22 mL of 68% concentrated nitric acid, stirring the mixture for 30 minutes at a reaction temperature of 0° C., then adding 12 g of potassium permanganate and stirring the mixture for 2 hours, then heating the mixture and stirring the mixture for 2 hours at a reaction temperature of 40° C., then heating the mixture and stirring the mixture for 1.5 hours at a reaction temperature of 98° C., then adding the mixture to 300 mL of 7% hydrogen peroxide and allowing the mixture to stand for 12 hours, then centrifuging the mixture, washing the mixture 3 times with a 5% hydrochloric acid solution and deionized water, and then drying the mixture to obtain a graphene sheet having a thickness of less than 5 nanometers;

[0062] Step S6: Dispersing polyvinylidene fluoride, copper nanoparticles, silver nanoparticles and graphene sheets in a polyvinyl pyrrolidone solution with a mass fraction of 5%, respectively, and then subjecting the solution to ultrasonic treatment to obtain uniformly dispersed base film material solution, copper nanoparticle dispersion, silver nanoparticle dispersion and graphene sheet dispersion, respectively; controlling the mass ratio of polyvinylidene fluoride to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of copper nanoparticles to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of silver nanoparticles to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of graphene sheets to polyvinyl pyrrolidone solution to be 1:5;

[0063] Step S7: stirring the base film material solution, the copper nanoparticle dispersion, the silver nanoparticle dispersion and the graphene sheet dispersion to obtain a mixed solution; wherein the mass ratio of polyvinylidene fluoride, copper nanoparticles, silver nanoparticles and graphene sheets in the mixed solution is 95.5:2:1:1.5;

[0064] Step S8: uniformly coating the blended solution on the substrate to form a coating film with a film thickness of 100 μm;

[0065] Step S9: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film;

[0066] Step S10: immersing the gelled film in deionized water for curing, the water bath time is 1.5 hours, and a cured film is obtained;

[0067] Step S11: drying the cured film at a drying temperature of 70° C. for 4 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

[0068] Embodiment 3:

[0069] This embodiment is a method for preparing an antibacterial filtration membrane for treating cutting fluid, comprising the following steps:

[0070] Step S1: dissolving copper nitrate in deionized water to obtain a copper salt solution with a molar concentration of 0.01 mol / L;

[0071] Step S2: adding ascorbic acid reducing agent to the copper salt solution, wherein the molar ratio of copper nitrate to ascorbic acid reducing agent is 1:5, and stirring the reaction at a reaction temperature of 80° C. for 30 minutes, followed by centrifugation, washing the precipitate with deionized water for 3 times, and then drying to obtain copper nanoparticles with an average particle size of 20 nanometers;

[0072] Step S3: dissolving silver nitrate in deionized water to obtain a silver salt solution with a molar concentration of 0.005 mol / L;

[0073] Step S4: adding glucose reducing agent to the silver salt solution, wherein the molar ratio of silver nitrate to glucose reducing agent is 1:20, and stirring the reaction at a reaction temperature of 70° C. for 80 minutes, followed by centrifugation, washing the precipitate with deionized water for 3 times, and then drying to obtain silver nanoparticles with an average particle size of 10 nanometers;

[0074] Step S5: adding 2 g of graphite powder to a mixed acid of 70 mL of 98% concentrated sulfuric acid and 22 mL of 68% concentrated nitric acid, stirring the mixture for 30 minutes at a reaction temperature of 0° C., then adding 12 g of potassium permanganate and stirring the mixture for 2 hours, then heating the mixture and stirring the mixture for 2 hours at a reaction temperature of 40° C., then heating the mixture and stirring the mixture for 1.5 hours at a reaction temperature of 98° C., then adding the mixture to 300 mL of 7% hydrogen peroxide and allowing the mixture to stand for 12 hours, then centrifuging the mixture, washing the mixture 3 times with a 5% hydrochloric acid solution and deionized water, and then drying the mixture to obtain a graphene sheet having a thickness of less than 5 nanometers;

[0075] Step S6: Dispersing polyvinylidene fluoride, copper nanoparticles, silver nanoparticles and graphene sheets in a polyvinyl pyrrolidone solution with a mass fraction of 5%, respectively, and then subjecting the solution to ultrasonic treatment to obtain uniformly dispersed base film material solution, copper nanoparticle dispersion, silver nanoparticle dispersion and graphene sheet dispersion, respectively; controlling the mass ratio of polyvinylidene fluoride to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of copper nanoparticles to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of silver nanoparticles to polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of graphene sheets to polyvinyl pyrrolidone solution to be 1:5;

[0076] Step S7: stirring the base film material solution, the copper nanoparticle dispersion, the silver nanoparticle dispersion and the graphene sheet dispersion to obtain a mixed solution; wherein the mass ratio of polyvinylidene fluoride, copper nanoparticles, silver nanoparticles and graphene sheets in the mixed solution is 90:5:3:2;

[0077] Step S8: uniformly coating the blended solution on the substrate to form a coating film with a film thickness of 100 μm;

[0078] Step S9: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film;

[0079] Step S10: immersing the gelled film in deionized water for curing, the water bath time is 2 hours, and a cured film is obtained;

[0080] Step S11: drying the cured film at a drying temperature of 80° C. for 6 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

[0081] Comparative Example 1:

[0082] This comparative example is a method for preparing an antibacterial filtration membrane for treating cutting fluid, comprising the following steps:

[0083] Step S1: dissolving copper nitrate in deionized water to obtain a copper salt solution with a molar concentration of 0.01 mol / L;

[0084] Step S2: adding ascorbic acid reducing agent to the copper salt solution, wherein the molar ratio of copper nitrate to ascorbic acid reducing agent is 1:5, and stirring the reaction at a reaction temperature of 80° C. for 30 minutes, followed by centrifugation, washing the precipitate with deionized water for 3 times, and then drying to obtain copper nanoparticles with an average particle size of 20 nanometers;

[0085] Step S3: dispersing polyvinylidene fluoride and copper nanoparticles in a polyvinyl pyrrolidone solution with a mass fraction of 5%, respectively, and then subjecting the solution to ultrasonic treatment to obtain a uniformly dispersed base film material solution and a copper nanoparticle dispersion, respectively; controlling the mass ratio of the polyvinylidene fluoride to the polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of the copper nanoparticles to the polyvinyl pyrrolidone solution to be 1:5;

[0086] Step S4: stirring the base film material solution and the copper nanoparticle dispersion to obtain a mixed solution; wherein the mass ratio of polyvinylidene fluoride to copper nanoparticles in the mixed solution is 90:5;

[0087] Step S5: uniformly coating the blended solution on the substrate to form a coating film with a film thickness of 100 μm;

[0088] Step S6: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film;

[0089] Step S7: immersing the gelled film in deionized water for curing, the water bath time is 2 hours, and a cured film is obtained;

[0090] Step S8: drying the cured film at a drying temperature of 80° C. for 6 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

[0091] Comparative Example 2:

[0092] This comparative example is a method for preparing an antibacterial filtration membrane for treating cutting fluid, comprising the following steps:

[0093] Step S1: dissolving silver nitrate in deionized water to obtain a silver salt solution with a molar concentration of 0.005 mol / L;

[0094] Step S2: adding glucose reducing agent to the silver salt solution, wherein the molar ratio of silver nitrate to glucose reducing agent is 1:20, and stirring the reaction at a reaction temperature of 70° C. for 80 minutes, followed by centrifugation, washing the precipitate with deionized water for 3 times, and then drying to obtain silver nanoparticles with an average particle size of 10 nanometers;

[0095] Step S3: dispersing polyvinylidene fluoride and silver nanoparticles in a polyvinyl pyrrolidone solution with a mass fraction of 5%, respectively, and then subjecting the solution to ultrasonic treatment to obtain a uniformly dispersed base film material solution and a silver nanoparticle dispersion, respectively; controlling the mass ratio of polyvinylidene fluoride to the polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of silver nanoparticles to the polyvinyl pyrrolidone solution to be 1:5;

[0096] Step S4: stirring the base film material solution and the silver nanoparticle dispersion to obtain a blended solution; wherein the mass ratio of polyvinylidene fluoride to silver nanoparticles in the blended solution is 90:3;

[0097] Step S5: uniformly coating the blended solution on the substrate to form a coating film with a film thickness of 100 μm;

[0098] Step S6: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film;

[0099] Step S7: immersing the gelled film in deionized water for curing, the water bath time is 2 hours, and a cured film is obtained;

[0100] Step S8: drying the cured film at a drying temperature of 80° C. for 6 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

[0101] Comparative Example 3:

[0102] This comparative example is a method for preparing an antibacterial filtration membrane for treating cutting fluid, comprising the following steps:

[0103] Step S1: 2 g of graphite powder is added to a mixed acid of 70 mL of 98% concentrated sulfuric acid and 22 mL of 68% concentrated nitric acid, and stirred for reaction at a reaction temperature of 0° C. for 30 minutes, then 12 g of potassium permanganate is added and stirred for reaction for 2 hours, then the temperature is raised and the stirring reaction is continued at a reaction temperature of 40° C. for 2 hours, then the temperature is raised and the stirring reaction is continued at a reaction temperature of 98° C. for 1.5 hours, then the mixture is added to 300 mL of 7% hydrogen peroxide and allowed to stand for 12 hours, then centrifuged, the precipitate is washed 3 times with a 5% hydrochloric acid solution and deionized water, and then dried to obtain a graphene sheet with a thickness of less than 5 nanometers;

[0104] Step S2: dispersing polyvinylidene fluoride and graphene sheets in a polyvinyl pyrrolidone solution with a mass fraction of 5%, respectively, and then ultrasonically treating to obtain a uniformly dispersed base film material solution and a graphene sheet dispersion solution, respectively; controlling the mass ratio of polyvinylidene fluoride and polyvinyl pyrrolidone solution to be 1:5; controlling the mass ratio of graphene sheets and polyvinyl pyrrolidone solution to be 1:5;

[0105] Step S3: stirring the base film material solution and the graphene sheet dispersion to obtain a mixed solution; wherein the mass ratio of polyvinylidene fluoride to graphene sheets in the mixed solution is 90:2;

[0106] Step S4: uniformly coating the blended solution on the substrate to form a coating film with a film thickness of 100 μm;

[0107] Step S5: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film;

[0108] Step S6: immersing the gelled film in deionized water for curing, the water bath time is 2 hours, and a cured film is obtained;

[0109] Step S7: drying the cured film at a drying temperature of 80° C. for 6 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

[0110] Comparative Example 4:

[0111] This comparative example is a method for preparing an antibacterial filtration membrane for treating cutting fluid, comprising the following steps:

[0112] Step S1: dispersing polyvinylidene fluoride in a polyvinyl pyrrolidone solution with a mass fraction of 5%, and then subjecting it to ultrasonic treatment to obtain a uniformly dispersed base film material solution; controlling the mass ratio of polyvinylidene fluoride to the polyvinyl pyrrolidone solution to be 1:5;

[0113] Step S2: uniformly coating the base film material solution on the substrate to form a coating film with a film thickness of 100 μm;

[0114] Step S3: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film;

[0115] Step S4: immersing the gelled film in deionized water for curing, the water bath time is 2 hours, and a cured film is obtained;

[0116] Step S5: drying the cured film at a drying temperature of 80° C. for 6 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

[0117] The antibacterial filtration membranes for treating cutting fluids of Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests, and the test results are shown in the following table:

[0118] sample Escherichia coli antibacterial rate, % Antibacterial rate of Staphylococcus aureus, % Tensile strength, MPa Example 1 98.4 98.1 46.3 Example 2 99.1 98.9 47.9 Example 3 99.9 99.8 49.6 Comparative Example 1 89.5 86.8 35.8 Comparative Example 2 93.7 91.2 34.1 Comparative Example 3 72.5 70.1 48.0 Comparative Example 4 52.8 50.5 31.2

[0119] Referring to the data in the above table, based on the comparison between Examples 1-3 and Comparative Examples 1-4, it can be seen that adding copper nanoparticles and silver nanoparticles to the antibacterial filter membrane can significantly improve its antibacterial properties, and adding graphene sheets thereto significantly enhances the tensile strength, and the synergistic effect of copper nanoparticles, silver nanoparticles and graphene sheets gives the antibacterial filter membrane excellent antibacterial effect and mechanical strength.

[0120] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0121] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. An antibacterial filtration membrane for treating cutting fluid, characterized in that: It comprises the following components in parts by weight: 90-98 parts of base film material, 0.5-5 parts of copper nanoparticles, 0.1-3 parts of silver nanoparticles and 0.5-2 parts of graphene sheets; The base film material is one of polyvinylidene fluoride, polyether sulfone and polypropylene; The average particle size of the copper nanoparticles is 10-50 nanometers; The average particle size of the silver nanoparticles is 5-20 nanometers; The thickness of the graphene sheet is less than 10 nanometers.

2. The antibacterial filtration membrane for treating cutting fluid according to claim 1, characterized in that: The copper nanoparticles are prepared by the following steps: Step a1: dissolving a copper salt in deionized water to obtain a copper salt solution with a molar concentration of 0.01 mol / L; Step a2: Add a reducing agent to the copper salt solution, and stir the reaction at a reaction temperature of 80° C. for 30 minutes, then centrifuge and separate, wash the precipitate with deionized water for 3 times, and then dry to obtain copper nanoparticles.

3. The antibacterial filtration membrane for treating cutting fluid according to claim 2, characterized in that: The copper salt is copper nitrate; the reducing agent is ascorbic acid; and the molar ratio of the copper salt to the reducing agent is 1:

5.

4. The antibacterial filtration membrane for treating cutting fluid according to claim 1, characterized in that: The silver nanoparticles are prepared by the following steps: Step b1: dissolving silver salt in deionized water to obtain a silver salt solution with a molar concentration of 0.005 mol / L; Step b2: Add a reducing agent to the silver salt solution, and stir the reaction at a reaction temperature of 70° C. for 80 minutes, then centrifuge and wash the precipitate with deionized water for 3 times, and then dry to obtain silver nanoparticles.

5. The antibacterial filtration membrane for treating cutting fluid according to claim 4, characterized in that: The silver salt is silver nitrate; the reducing agent is glucose; and the molar ratio of the silver salt to the reducing agent is 1:

20.

6. The antibacterial filtration membrane for treating cutting fluid according to claim 1, characterized in that: The graphene sheet is prepared by the following steps: Graphite powder was added to a mixed acid of concentrated sulfuric acid and concentrated nitric acid, and the reaction was stirred for 30 minutes at a reaction temperature of 0°C. Potassium permanganate was then added and the reaction was continued to stir for 2 hours. The temperature was then raised and the reaction was continued to stir for 2 hours at a reaction temperature of 40°C. The temperature was then raised and the reaction was continued to stir for 1.5 hours at a reaction temperature of 98°C. The mixture was then added to hydrogen peroxide and allowed to stand for 12 hours. The mixture was then centrifuged and the precipitate was washed 3 times with hydrochloric acid solution and deionized water, and then dried to obtain a graphene sheet.

7. The antibacterial filtration membrane for treating cutting fluid according to claim 6, characterized in that: The usage ratio of the graphite powder, concentrated sulfuric acid, concentrated nitric acid, potassium permanganate and hydrogen peroxide is 2g:70mL:22mL:12g:300mL.

8. The antibacterial filtration membrane for treating cutting fluid according to claim 6, characterized in that: The mass fraction of the concentrated sulfuric acid is 98%, the mass fraction of the concentrated nitric acid is 68%, the mass fraction of the hydrogen peroxide is 7%, and the mass fraction of the hydrochloric acid solution is 5%.

9. A method for preparing an antibacterial filtration membrane for treating cutting fluid, characterized in that: The following steps are involved: Step 1: Dispersing the base film material, copper nanoparticles, silver nanoparticles and graphene sheets in a polyvinyl pyrrolidone solution respectively, and then subjecting the solution to ultrasonic treatment to obtain uniformly dispersed base film material solution, copper nanoparticle dispersion, silver nanoparticle dispersion and graphene sheet dispersion respectively; Step 2: uniformly stirring the base film material solution, the copper nanoparticle dispersion, the silver nanoparticle dispersion and the graphene sheet dispersion to obtain a mixed solution; wherein the mass ratio of the base film material, the copper nanoparticles, the silver nanoparticles and the graphene sheet in the mixed solution is 90-98:0.5-5:0.1-3:0.5-2; Step 3: evenly coating the blended solution on the substrate to form a coating film with a film thickness of 50-200 microns; Step 4: placing the coated film at room temperature for 30 minutes to form a gel layer on its surface to obtain a gel film; Step 5: Immerse the gelled film in deionized water for curing, the water bath time is 0.5-2 hours, and a cured film is obtained; Step 6: Dry the cured film at a drying temperature of 60-80° C. for 2-6 hours to obtain an antibacterial filtration membrane for treating cutting fluid.

10. The method for preparing an antibacterial filtration membrane for treating cutting fluid according to claim 9, characterized in that: The polyvinyl pyrrolidone solution is a polyvinyl pyrrolidone aqueous solution with a mass fraction of 5%; the mass ratio of the base film material and the polyvinyl pyrrolidone solution is 1:5; the mass ratio of the copper nanoparticles and the polyvinyl pyrrolidone solution is 1:5; the mass ratio of the silver nanoparticles and the polyvinyl pyrrolidone solution is 1:5; the mass ratio of the graphene sheets and the polyvinyl pyrrolidone solution is 1:5.