A polymer / nanomaterial composite filter membrane and its preparation method

Abstract

This invention relates to the field of composite filtration membrane technology, specifically disclosing a polymer / nanomaterial composite filtration membrane. The composite filtration membrane is obtained by immersing a non-woven fabric base layer in a 3-5 times solution of hydrochloric acid; then, a polymer / nanomaterial modifier is applied to the surface of the modified non-woven fabric base layer using a curing film-forming technology to form a nanofiber membrane layer; finally, the membrane is treated in a modification solution to obtain the composite filtration membrane of this invention. The composite filtration membrane of this invention first immerses the non-woven fabric base layer in hydrochloric acid solution to enhance its activity, facilitating the subsequent curing film-forming process to form the nanofiber membrane layer. The polymer / nanomaterial modifier, through curing film-forming technology combined with the modification solution treatment, enhances the product's antibacterial properties, antibacterial durability, and filtration performance.

Description

Technical Field

[0001] This invention relates to the field of filtration membrane technology, specifically to a polymer / nanomaterial composite filtration membrane and its preparation method. Background Technology

[0002] Filtration membranes, also known as microporous filtration membranes, are used in the production of raw pharmaceutical materials, pharmaceutical solvents, water for injection, and injections. Types include mixed fiber microporous membranes. Filtration membranes are classified according to the size of the particles they trap in the raw water, with pore sizes ranging from coarse to fine: microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO). MF membranes have pore sizes greater than 0.05 μm or with molecular weights greater than 1000, primarily removing colloids and high-molecular-weight organic matter. NF membranes have pore sizes between 100 and 1000 molecular weights. They remove substances between those removed by UF and RO, primarily removing trihalomethanes, odors, color, pesticides, soluble organic matter, calcium, magnesium, etc. RO separates particles with molecular weights in the tens, primarily removing salts and inorganic salts; the pressure of the RO permeate water is 1 to 2 times higher than its osmotic pressure. In addition to these four types, there are ion exchange membranes and gas permeation membranes. MF, UF, NF, and RO use pressure to drive solid-liquid separation. Ion exchange membranes use electricity to separate salt molecules, facilitating seawater desalination. Gas permeation membranes are a recently developed type of membrane that allows gas to pass through, enabling ethanol concentration and seawater desalination.

[0003] Existing composite filter membranes have poor antibacterial properties, and their antibacterial effect is unstable and has low long-lasting antibacterial efficiency. In the prior art, in order to improve the antibacterial effect, it is easy to reduce the particulate matter filtration efficiency of the product. This invention modifies and optimizes them to coordinate and improve the antibacterial and filtration performance effects, and provides a polymer / nanomaterial composite filter membrane and its preparation method. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a polymer / nanomaterial composite filter membrane and its preparation method, thereby solving the problems mentioned in the background section.

[0005] The present invention solves the technical problem by adopting the following technical solution:

[0006] This invention provides a polymer / nanomaterial composite filter membrane, wherein the composite filter membrane is a non-woven fabric base layer treated by immersion in 3-5 times the amount of hydrochloric acid solution;

[0007] The polymer / nanomaterial modifier is then cured and film-forming agent to form a nanofiber membrane layer on the surface of the modified nonwoven fabric substrate; after treatment in the modification solution, the composite filter membrane of the present invention can be obtained.

[0008] Preferably, the hydrochloric acid solution has a mass fraction of 5-10%.

[0009] Preferably, the curing film-forming technology is as follows: the polymer / nanomaterial modified composite agent is sprayed out into a tubular liquid film through a spinneret. After passing through an air gap of 6-8 cm, the liquid film enters a water bath at 20°C and is cured into a nanofiber film. Then, it is soaked and washed in water at 25°C for 2 days and dried. Finally, the nanofiber film is bonded to the treated and modified nonwoven fabric base layer with an adhesive.

[0010] Preferably, the preparation method of the polymer / nanomaterial modified composite agent is as follows:

[0011] S01: Add 5-10 parts of polymer material to 30-40 parts of solvent, then add 2-6 parts of polyvinylpyrrolidone and stir until homogeneous;

[0012] S02: Add 1-4 parts of thermoplastic resin to 20-30 parts of 95% ethanol by mass, then add 3-6 parts of modified nano-bentonite and 5-10 parts of nano-silver, and stir until well mixed.

[0013] S03: Add 2-6 parts of the conditioning modifier to S02 and stir thoroughly;

[0014] S04: Then add it together with the product S01, stir and mix thoroughly to obtain a polymer / nanomaterial modified composite agent.

[0015] Preferably, the polymer material is polyacrylonitrile; the solvent is N,N-dimethylacetamide; and the thermoplastic resin is PE-polyethylene.

[0016] Preferably, the preparation steps of the formulation modifier are as follows:

[0017] S11: Add lanthanum sulfate to the chitosan solution at a weight ratio of 1:5, then add 2-5% of the total lanthanum sulfate in phosphate buffer solution and stir until homogeneous;

[0018] S12: Add hydroxyapatite to 5-10 times its volume of sodium alginate solution, stir to disperse evenly, then wash with water and dry;

[0019] S13: Add the hydroxyapatite treated by S12 to the product of S11 at a weight ratio of 1:5, stir and mix thoroughly to obtain the conditioning modifier.

[0020] Preferably, the pH of the phosphate buffer solution is 5.0-6.0; the mass fraction of the chitosan solution is 10-20%; and the mass fraction of the sodium alginate solution is 10-20%.

[0021] Preferably, the modified nano-bentonite is prepared by:

[0022] The nano-bentonite is fed into a calcining furnace and calcined for 20-30 minutes at a temperature of 350-450℃. Then, it is cooled to 35-45℃ at a rate of 2-5℃ / min and then added to 3-5 times its volume of deionized water and stirred to disperse evenly. Finally, it is washed with water and dried to obtain modified nano-bentonite.

[0023] Preferably, the modified treatment liquid comprises the following raw materials in parts by weight:

[0024] Sodium dodecyl sulfate 3-6 parts, water 45-55 parts, silane coupling agent KH560 1-3 parts, hydrochloric acid solution with a mass fraction of 3-6% 2-6 parts.

[0025] This invention also provides a method for preparing a polymer / nanomaterial composite filter membrane, comprising the following steps:

[0026] Step 1: Soak the non-woven fabric base layer in hydrochloric acid solution at a temperature of 35-38℃ for 1-2 hours, then remove, wash with water, and air dry.

[0027] Step 2: The polymer / nanomaterial modifier is applied to the surface of the modified nonwoven fabric substrate to form a nanofiber film using a curing film-forming technology; the diameter of the nanofiber film is 1-2 micrometers.

[0028] Step 3: Finally, ultrasonically treat the modified solution with a power of 100-200W, a treatment time of 10-20 minutes, and a treatment temperature of 35-40℃. After treatment, wash with water and dry.

[0029] Step 4: Finally, treat under a pressure of 10-15 MPa for 5-10 minutes to obtain the composite filter membrane.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The composite filter membrane of the present invention is first soaked in hydrochloric acid solution through a non-woven base layer to improve the activity of the base layer, which facilitates the subsequent curing and film formation to form a nanofiber membrane layer. The polymer / nanomaterial modifier is treated with a curing film forming technology and a modification treatment liquid to enhance the antibacterial properties, antibacterial durability and filtration performance of the product.

[0032] 2. The polymer / nanomaterial modified composite agent forms a base liquid through polymer materials, polyvinylpyrrolidone, and solvents; thermoplastic resin has polymer chains that are prone to entanglement, which are penetrated and traversed through the layered structure of nano-bentonite, improving and optimizing the resin molecular chains. The two are synergistically improved to enhance the strength and stability of the nanofiber membrane matrix. Meanwhile, nano-silver has antibacterial properties. Through the optimized modification of nano-bentonite and the formulation of the modifier, the two work synergistically to enhance antibacterial stability and filtration efficiency.

[0033] 3. After calcination and constant-temperature cooling, the interlayer spacing of nano-bentonite expands. Then, it is dispersed in deionized water, which improves the dispersion and optimizes the thermoplastic resin molecular chain, thus enhancing the stability of the product. The expanded interlayer spacing also enhances the flow of filtered material through the interlayer channels, making subsequent filtration more effective.

[0034] 4. The lanthanum sulfate, chitosan solution, and phosphate buffer solution in the modifier provide an active medium, which facilitates the enhancement of the interfacial properties between the raw materials in the polymer / nanomaterial modifier composite. After treatment with sodium alginate solution, the dispersibility of hydroxyapatite is enhanced. At the same time, its porous nature and easy adhesion to the bentonite sheet channels further enhance the filtration performance of the product. Meanwhile, the antibacterial stability of the product is also significantly improved.

[0035] 5. The modified treatment solution uses sodium dodecyl sulfate in combination with silane coupling agent and hydrochloric acid solution to enhance the surface activity of the raw materials of the composite membrane product on the one hand, and enhance the interfacial effect between the raw materials on the other hand. It is treated under a pressure of 10-15MPa for 5-10 minutes. Through co-coupling and pressurization treatment, the stability of the product is further improved, thereby significantly enhancing the antibacterial properties, antibacterial durability and filtration performance of the product. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] This embodiment describes a polymer / nanomaterial composite filter membrane, wherein the composite filter membrane is a non-woven fabric base layer that has been treated by soaking in 3-5 times the amount of hydrochloric acid solution;

[0038] The polymer / nanomaterial modifier is then cured and film-forming agent to form a nanofiber membrane layer on the surface of the modified nonwoven fabric substrate; after treatment in the modification solution, the composite filter membrane of the present invention can be obtained.

[0039] The hydrochloric acid solution in this embodiment has a mass fraction of 5-10%.

[0040] The curing film-forming technology in this embodiment is as follows: the polymer / nanomaterial modified composite agent is sprayed out into a tubular liquid film through a spinneret. After passing through an air gap of 6-8 cm, the liquid film enters a water bath at 20°C and is cured into a nanofiber film. Then, it is soaked and cleaned in water at 25°C for 2 days and dried. Finally, the nanofiber film is bonded to the treated and modified nonwoven fabric base layer with an adhesive.

[0041] The preparation method of the polymer / nanomaterial modified composite agent in this embodiment is as follows:

[0042] S01: Add 5-10 parts of polymer material to 30-40 parts of solvent, then add 2-6 parts of polyvinylpyrrolidone and stir until homogeneous;

[0043] S02: Add 1-4 parts of thermoplastic resin to 20-30 parts of 95% ethanol by mass, then add 3-6 parts of modified nano-bentonite and 5-10 parts of nano-silver, and stir until well mixed.

[0044] S03: Add 2-6 parts of the conditioning modifier to S02 and stir thoroughly;

[0045] S04: Then add it together with the product S01, stir and mix thoroughly to obtain a polymer / nanomaterial modified composite agent.

[0046] In this embodiment, the polymer material is polyacrylonitrile; the solvent is N,N-dimethylacetamide; and the thermoplastic resin is PE-polyethylene.

[0047] The preparation steps of the formulation modifier in this embodiment are as follows:

[0048] S11: Add lanthanum sulfate to the chitosan solution at a weight ratio of 1:5, then add 2-5% of the total lanthanum sulfate in phosphate buffer solution and stir until homogeneous;

[0049] S12: Add hydroxyapatite to 5-10 times its volume of sodium alginate solution, stir to disperse evenly, then wash with water and dry;

[0050] S13: Add the hydroxyapatite treated by S12 to the product of S11 at a weight ratio of 1:5, stir and mix thoroughly to obtain the conditioning modifier.

[0051] The pH of the phosphate buffer solution in this embodiment is 5.0-6.0; the mass fraction of the chitosan solution is 10-20%; and the mass fraction of the sodium alginate solution is 10-20%.

[0052] The preparation method of the modified nano-bentonite in this embodiment is as follows:

[0053] The nano-bentonite is fed into a calcining furnace and calcined for 20-30 minutes at a temperature of 350-450℃. Then, it is cooled to 35-45℃ at a rate of 2-5℃ / min and then added to 3-5 times its volume of deionized water and stirred to disperse evenly. Finally, it is washed with water and dried to obtain modified nano-bentonite.

[0054] The modified treatment liquid in this embodiment comprises the following raw materials in parts by weight:

[0055] Sodium dodecyl sulfate 3-6 parts, water 45-55 parts, silane coupling agent KH560 1-3 parts, hydrochloric acid solution with a mass fraction of 3-6% 2-6 parts.

[0056] This embodiment describes a method for preparing a polymer / nanomaterial composite filter membrane, comprising the following steps:

[0057] Step 1: Soak the non-woven fabric base layer in hydrochloric acid solution at a temperature of 35-38℃ for 1-2 hours, then remove, wash with water, and air dry.

[0058] Step 2: The polymer / nanomaterial modifier is applied to the surface of the modified nonwoven fabric substrate to form a nanofiber film using a curing film-forming technology; the diameter of the nanofiber film is 1-2 micrometers.

[0059] Step 3: Finally, ultrasonically treat the modified solution with a power of 100-200W, a treatment time of 10-20 minutes, and a treatment temperature of 35-40℃. After treatment, wash with water and dry.

[0060] Step 4: Finally, treat under a pressure of 10-15 MPa for 5-10 minutes to obtain the composite filter membrane.

[0061] Example 1.

[0062] This embodiment describes a polymer / nanomaterial composite filter membrane, wherein the composite filter membrane is a non-woven fabric base layer that has been treated by immersion in a hydrochloric acid solution three times its volume.

[0063] The polymer / nanomaterial modifier is then cured and film-forming agent to form a nanofiber membrane layer on the surface of the modified nonwoven fabric substrate; after treatment in the modification solution, the composite filter membrane of the present invention can be obtained.

[0064] The hydrochloric acid solution in this embodiment has a mass fraction of 5%.

[0065] The curing film-forming technology in this embodiment is as follows: the polymer / nanomaterial modified composite agent is sprayed out into a tubular liquid film through a spinneret. After passing through a 6cm air gap, the liquid film enters a 20°C water bath and is cured into a nanofiber film. Then, it is soaked and cleaned in 25°C water for 2 days and dried. Finally, the nanofiber film is bonded to the treated and modified nonwoven fabric base layer with an adhesive.

[0066] The preparation method of the polymer / nanomaterial modified composite agent in this embodiment is as follows:

[0067] S01: Add 5 parts of polymer material to 30 parts of solvent, then add 2 parts of polyvinylpyrrolidone and stir until homogeneous;

[0068] S02: Add 1 part of thermoplastic resin to 20 parts of 95% ethanol by mass, then add 3 parts of modified nano-bentonite and 5 parts of nano-silver, and stir until well mixed.

[0069] S03: Add 2 parts of the formulation modifier to S02 and stir thoroughly;

[0070] S04: Then add it together with the product S01, stir and mix thoroughly to obtain a polymer / nanomaterial modified composite agent.

[0071] In this embodiment, the polymer material is polyacrylonitrile; the solvent is N,N-dimethylacetamide; and the thermoplastic resin is PE-polyethylene.

[0072] The preparation steps of the formulation modifier in this embodiment are as follows:

[0073] S11: Add lanthanum sulfate to the chitosan solution at a weight ratio of 1:5, then add 2% of the total lanthanum sulfate in phosphate buffer solution and stir until homogeneous;

[0074] S12: Add hydroxyapatite to 5 times the amount of sodium alginate solution, stir to disperse evenly, then wash with water and dry;

[0075] S13: Add the hydroxyapatite treated by S12 to the product of S11 at a weight ratio of 1:5, stir and mix thoroughly to obtain the conditioning modifier.

[0076] In this embodiment, the pH of the phosphate buffer solution is 5.0; the mass fraction of the chitosan solution is 10%; and the mass fraction of the sodium alginate solution is 10%.

[0077] The preparation method of the modified nano-bentonite in this embodiment is as follows:

[0078] The nano-bentonite was fed into a calcining furnace and calcined for 20 minutes at a temperature of 350°C. Then, it was reduced to 35°C at a rate of 2°C / min and then added to 3 times the volume of deionized water and stirred to disperse evenly. Finally, it was washed with water and dried to obtain modified nano-bentonite.

[0079] The modified treatment liquid in this embodiment comprises the following raw materials in parts by weight:

[0080] 3 parts sodium dodecyl sulfate, 45 parts water, 1 part silane coupling agent KH560, and 2 parts hydrochloric acid solution with a mass fraction of 3%.

[0081] This embodiment describes a method for preparing a polymer / nanomaterial composite filter membrane, comprising the following steps:

[0082] Step 1: Soak the non-woven fabric base layer in hydrochloric acid solution at 35℃ for 1 hour, then remove, wash with water, and air dry.

[0083] Step 2: The polymer / nanomaterial modifier is cured and film-forming agent to form a nanofiber film on the surface of the modified nonwoven fabric substrate; the diameter of the nanofiber film is 1 micrometer.

[0084] Step 3: Finally, ultrasonically treat the modified solution with a power of 100W for 10 minutes at a temperature of 35℃. After treatment, wash with water and dry.

[0085] Step 4: Finally, process under a pressure of 10 MPa for 5 minutes to obtain the composite filter membrane.

[0086] Example 2.

[0087] This embodiment describes a polymer / nanomaterial composite filter membrane, wherein the composite filter membrane is a non-woven fabric base layer treated by immersion in a 5-fold hydrochloric acid solution;

[0088] The polymer / nanomaterial modifier is then cured and film-forming agent to form a nanofiber membrane layer on the surface of the modified nonwoven fabric substrate; after treatment in the modification solution, the composite filter membrane of the present invention can be obtained.

[0089] The hydrochloric acid solution in this embodiment has a mass fraction of 10%.

[0090] The curing film-forming technology in this embodiment is as follows: the polymer / nanomaterial modified composite agent is sprayed out into a tubular liquid film through a spinneret. After passing through an 8cm air gap, the liquid film enters a 20°C water bath and is cured into a nanofiber film. Then, it is soaked and cleaned in 25°C water for 2 days and dried. Finally, the nanofiber film is bonded to the treated and modified nonwoven fabric base layer with an adhesive.

[0091] The preparation method of the polymer / nanomaterial modified composite agent in this embodiment is as follows:

[0092] S01: Add 10 parts of polymer material to 40 parts of solvent, then add 6 parts of polyvinylpyrrolidone and stir until homogeneous;

[0093] S02: Add 4 parts of thermoplastic resin to 30 parts of 95% ethanol by mass, then add 6 parts of modified nano-bentonite and 10 parts of nano-silver, and stir until well mixed.

[0094] S03: Add 6 parts of the formulation modifier to S02 and stir thoroughly;

[0095] S04: Then add it together with the product S01, stir and mix thoroughly to obtain a polymer / nanomaterial modified composite agent.

[0096] In this embodiment, the polymer material is polyacrylonitrile; the solvent is N,N-dimethylacetamide; and the thermoplastic resin is PE-polyethylene.

[0097] The preparation steps of the formulation modifier in this embodiment are as follows:

[0098] S11: Add lanthanum sulfate to the chitosan solution at a weight ratio of 1:5, then add 5% of the total lanthanum sulfate in phosphate buffer solution and stir until homogeneous;

[0099] S12: Add hydroxyapatite to 10 times the amount of sodium alginate solution, stir to disperse evenly, then wash with water and dry;

[0100] S13: Add the hydroxyapatite treated by S12 to the product of S11 at a weight ratio of 1:5, stir and mix thoroughly to obtain the conditioning modifier.

[0101] In this embodiment, the pH of the phosphate buffer solution is 6.0; the mass fraction of the chitosan solution is 20%; and the mass fraction of the sodium alginate solution is 20%.

[0102] The preparation method of the modified nano-bentonite in this embodiment is as follows:

[0103] The nano-bentonite was fed into a calcining furnace and calcined for 30 minutes at a temperature of 450°C. Then, it was cooled to 45°C at a rate of 5°C / min and then added to 5 times its volume of deionized water and stirred to disperse evenly. Finally, it was washed with water and dried to obtain modified nano-bentonite.

[0104] The modified treatment liquid in this embodiment comprises the following raw materials in parts by weight:

[0105] 6 parts sodium dodecyl sulfate, 55 parts water, 3 parts silane coupling agent KH560, and 6 parts hydrochloric acid solution with a mass fraction of 6%.

[0106] This embodiment describes a method for preparing a polymer / nanomaterial composite filter membrane, comprising the following steps:

[0107] Step 1: Soak the non-woven fabric base layer in hydrochloric acid solution at 38℃ for 2 hours, then remove, wash with water, and air dry.

[0108] Step 2: The polymer / nanomaterial modifier is cured and film-forming agent to form a nanofiber film on the surface of the modified nonwoven fabric substrate; the diameter of the nanofiber film is 2 micrometers.

[0109] Step 3: Finally, ultrasonically treat the modified solution with a power of 200W for 20 minutes at a temperature of 40℃. After treatment, rinse with water and dry.

[0110] Step 4: Finally, process under a pressure of 15 MPa for 10 minutes to obtain the composite filter membrane.

[0111] Example 3.

[0112] This embodiment describes a polymer / nanomaterial composite filter membrane, wherein the composite filter membrane is a non-woven fabric base layer that has been treated by immersion in a 4 times hydrochloric acid solution.

[0113] The polymer / nanomaterial modifier is then cured and film-forming agent to form a nanofiber membrane layer on the surface of the modified nonwoven fabric substrate; after treatment in the modification solution, the composite filter membrane of the present invention can be obtained.

[0114] The hydrochloric acid solution in this embodiment has a mass fraction of 7.5%.

[0115] The curing film-forming technology in this embodiment is as follows: the polymer / nanomaterial modified composite agent is sprayed out into a tubular liquid film through a spinneret. After passing through a 7cm air gap, the liquid film enters a 20°C water bath and is cured into a nanofiber film. Then, it is soaked and washed in 25°C water for 2 days and dried. Finally, the nanofiber film is bonded to the treated and modified nonwoven fabric base layer with an adhesive.

[0116] The preparation method of the polymer / nanomaterial modified composite agent in this embodiment is as follows:

[0117] S01: Add 7.5 parts of polymer material to 35 parts of solvent, then add 4 parts of polyvinylpyrrolidone and stir until homogeneous;

[0118] S02: Add 2.5 parts of thermoplastic resin to 25 parts of 95% ethanol by mass, then add 4.5 parts of modified nano-bentonite and 7.5 parts of nano-silver, and stir to mix evenly.

[0119] S03: Add 4 parts of the formulation modifier to S02 and stir thoroughly;

[0120] S04: Then add it together with the product S01, stir and mix thoroughly to obtain a polymer / nanomaterial modified composite agent.

[0121] In this embodiment, the polymer material is polyacrylonitrile; the solvent is N,N-dimethylacetamide; and the thermoplastic resin is PE-polyethylene.

[0122] The preparation steps of the formulation modifier in this embodiment are as follows:

[0123] S11: Add lanthanum sulfate to the chitosan solution at a weight ratio of 1:5, then add 3.5% of the total lanthanum sulfate in phosphate buffer solution and stir until homogeneous;

[0124] S12: Add hydroxyapatite to 5-10 times its volume of sodium alginate solution, stir to disperse evenly, then wash with water and dry;

[0125] S13: Add the hydroxyapatite treated by S12 to the product of S11 at a weight ratio of 1:5, stir and mix thoroughly to obtain the conditioning modifier.

[0126] In this embodiment, the pH of the phosphate buffer solution is 5.5; the mass fraction of the chitosan solution is 15%; and the mass fraction of the sodium alginate solution is 15%.

[0127] The preparation method of the modified nano-bentonite in this embodiment is as follows:

[0128] The nano-bentonite was fed into a calcining furnace and calcined for 25 minutes at a temperature of 400℃. Then, it was cooled to 40℃ at a rate of 3.5℃ / min and then added to 4 times its volume of deionized water and stirred to disperse evenly. Finally, it was washed with water and dried to obtain modified nano-bentonite.

[0129] The modified treatment liquid in this embodiment comprises the following raw materials in parts by weight:

[0130] 4.5 parts sodium dodecyl sulfate, 50 parts water, 3 parts silane coupling agent KH560, and 4 parts hydrochloric acid solution with a mass fraction of 4.5%.

[0131] This embodiment describes a method for preparing a polymer / nanomaterial composite filter membrane, comprising the following steps:

[0132] Step 1: Soak the non-woven fabric base layer in hydrochloric acid solution at 36℃ for 1.5 hours, then remove, wash with water, and air dry.

[0133] Step 2: The polymer / nanomaterial modifier is cured and film-forming agent to form a nanofiber film on the surface of the modified nonwoven fabric substrate; the diameter of the nanofiber film is 1.5 micrometers.

[0134] Step 3: Finally, ultrasonically treat the sample in the modified treatment solution at a power of 150W for 15 minutes at a temperature of 37.5℃. After treatment, rinse with water and dry.

[0135] Step 4: Finally, process under a pressure of 12.5 MPa for 7.5 min to obtain the composite filter membrane.

[0136] Comparative Example 1.

[0137] Unlike Example 3, no modified nano-bentonite was added in the preparation of the polymer / nanomaterial modified composite agent.

[0138] Comparative Example 2.

[0139] Unlike Example 3, no modifier was added during the preparation of the polymer / nanomaterial modified composite.

[0140] Comparative Example 3.

[0141] Unlike Example 3, the modified nano-bentonite is replaced with nano-bentonite.

[0142] Comparative Example 4.

[0143] Unlike Example 3, the modified nano-bentonite was not cooled to 35-45°C at a rate of 2-5°C / min, but was directly cooled to room temperature.

[0144] Comparative Example 5.

[0145] Unlike Example 3, no modified treatment solution was used.

[0146] Comparative Example 6.

[0147] Unlike Example 3, the modified treatment solution does not contain the silane coupling agent KH560.

[0148] Comparative Example 7.

[0149] Unlike Example 3, the modified treatment solution does not contain sodium dodecyl sulfate.

[0150] Comparative Example 8.

[0151] Unlike Example 3, the modified treatment solution does not include hydrochloric acid solution.

[0152] Comparative Example 9.

[0153] Unlike Example 3, this method did not involve treatment at a pressure of 10-15 MPa for 5-10 minutes.

[0154] Referring to the standard GB / T20944.3-2008 "Evaluation of antimicrobial properties of textiles - Part 3: Shaking method", Staphylococcus aureus was selected as the test species. The antimicrobial inhibition rate of the samples was calculated.

[0155] Particulate matter filtration efficiency determination: Referring to the standard GB2626-2019 Respiratory Protection Self-priming Filtering Particulate Respirator, the membrane sample was cut into a circular sample with a diameter of 12 cm. Under the condition of gas flow rate of 85 L / min, the filtration efficiency of the sample for saline aerosol (NaCl) particles with a mass median diameter of 0.3 μm was tested. Five samples under the same preparation conditions were tested repeatedly, and the minimum value was taken as the final test result.

[0156] The tensile strength and elongation at break of the membrane were tested using an AGS-5D automatic plotter at a sample length of 50 mm, a tensile speed of 10 mm / min, and a temperature of 25 °C. Tensile strength was expressed as the load on each nanofiber membrane at fracture, and elongation at break was expressed as the ratio of the elongation at fracture to the original length.

[0157] The performance measurement results of Examples 1-3 and Comparative Examples 1-9 are as follows:

[0158]

[0159] From Examples 1-3 and Comparative Examples 1-9, it was found that...

[0160] The Staphylococcus aureus inhibition rate of Example 3 of the present invention is as high as 99.99%, the filtration efficiency is as high as 99.96%, and the tensile strength and elongation at break are 0.68Kgf and 73%, respectively.

[0161] As can be seen from Comparative Examples 1-2 and Example 3, when modified nano-bentonite was not added during the preparation of the polymer / nanomaterial modified composite, the filtration efficiency, tensile strength and elongation at break of the product all changed significantly. At the same time, when no modifier was added, the performance of the product also showed a significant deterioration trend.

[0162] As can be seen from Comparative Examples 3-4, the performance of the modified nano-bentonite tends to deteriorate when nano-bentonite is replaced with nano-bentonite or when the preparation method of nano-bentonite is different. Only the modified nano-bentonite prepared by the method of the present invention shows excellent improvement in product performance.

[0163] Comparative Examples 5-8 show that without the use of the modified treatment solution, the filtration performance, tensile strength, and elongation at break of the products all tend to deteriorate to varying degrees. Furthermore, the performance of the products deteriorates when none of the following are added to the modified treatment solution: sodium dodecyl sulfate, silane coupling agent KH560, or 4.5% hydrochloric acid solution. Only when the raw materials in the modified treatment solution are combined and formulated in a synergistic manner does the product exhibit the best performance.

[0164] Based on the above tests, we will continue to test the product's antibacterial durability:

[0165]

[0166]

[0167] After being washed 10, 20, and 60 times, the products in Examples 1-3 still exhibited excellent antibacterial properties, demonstrating significant antibacterial durability.

[0168] Comparative Examples 1-4 show that without the addition of modified nano-bentonite, the antibacterial durability of the product decreased significantly. Modified nano-bentonite has a significant effect on the antibacterial stability of the product. Without the addition of the modifier, the antibacterial durability also tended to deteriorate. The use of modified nano-bentonite and the addition of the modifier can achieve a synergistic effect and enhance the antibacterial stability of the product.

[0169] Meanwhile, comparative examples 5-8 show that the antibacterial stability of the products decreased when no modified treatment solution was used or when the composition of the modified solution was different. Only the modified treatment solution prepared by the method of this invention significantly improved the antibacterial stability of the products. In addition, treatment at a pressure of 10-15 MPa for 5-10 minutes can be combined with the modified treatment solution to enhance the antibacterial stability of the products.

[0170] Based on the above tests, this invention found that the formulation of modifiers has a significant impact on the performance of products. Based on this, this invention further explores this issue.

[0171] The preparation steps for the modifier are as follows:

[0172] S11: Add lanthanum sulfate to the chitosan solution at a weight ratio of 1:5, then add 2-5% of the total lanthanum sulfate in phosphate buffer solution and stir until homogeneous;

[0173] S12: Add hydroxyapatite to 5-10 times its volume of sodium alginate solution, stir to disperse evenly, then wash with water and dry;

[0174] S13: Add the hydroxyapatite treated by S12 to the product of S11 at a weight ratio of 1:5, stir and mix thoroughly to obtain the conditioning modifier.

[0175] The pH of the phosphate buffer solution in this embodiment is 5.0-6.0; the mass fraction of the chitosan solution is 10-20%; and the mass fraction of the sodium alginate solution is 10-20%.

[0176] Experimental Example 1.

[0177] Same as Example 3, except that chitosan solution was not added in the preparation of the modifier.

[0178] Experimental Example 2.

[0179] Same as Example 3, except that lanthanum sulfate was not added in the preparation of the modifier.

[0180] Experimental Example 3.

[0181] Same as Example 3, except that S12-treated hydroxyapatite was not added in the preparation of the modifier.

[0182] Experimental Example 4.

[0183] Same as Example 3, except that the hydroxyapatite treated in S12 is replaced with hydroxyapatite.

[0184] Experimental Example 5.

[0185] Same as Example 3, except that the hydroxyapatite in the S12-treated hydroxyapatite is replaced with graphene.

[0186]

[0187] As can be seen from Experiments 1-5, when chitosan solution, lanthanum sulfate, and S12-treated hydroxyapatite were not added during the preparation of the formulation modifier, the Staphylococcus aureus inhibition rate, tensile strength, and filtration efficiency of the product after 60 washes all showed a deteriorating trend. The deterioration trend was most pronounced when S12-treated hydroxyapatite was not added, possibly because hydroxyapatite plays the most important role in the formulation modifier. Furthermore, the inventors also found that when graphene was used instead of hydroxyapatite in the S12-treated hydroxyapatite, the filtration efficiency of the product decreased more significantly, and the tensile strength, Staphylococcus aureus inhibition rate after 60 washes, and other product performance all showed a deteriorating trend. Therefore, hydroxyapatite cannot be replaced by other raw materials. Only by using the method of this invention, combined with the formulation modifier prepared using hydroxyapatite, can the product's performance be enhanced synergistically with the modified nano-bentonite.

[0188] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0189] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A polymer / nanomaterial composite filter membrane, characterized in that, The composite filter membrane is made of non-woven fabric base layer that has been treated by soaking in 3-5 times the amount of hydrochloric acid solution; The polymer / nanomaterial modifier is then cured and film-forming agent to form a nanofiber membrane layer on the surface of the modified nonwoven fabric substrate; after treatment in the modification solution, a composite filter membrane can be obtained. The preparation method of the polymer / nanomaterial modified composite agent is as follows: S01: Add 5-10 parts of polymer material to 30-40 parts of solvent, then add 2-6 parts of polyvinylpyrrolidone and stir until homogeneous; S02: Add 1-4 parts of thermoplastic resin to 20-30 parts of 95% ethanol by mass, then add 3-6 parts of modified nano-bentonite and 5-10 parts of nano-silver, and stir until well mixed. S03: Add 2-6 parts of the conditioning modifier to S02 and stir thoroughly; S04: Then add it together to the product S01, and continue to stir and mix thoroughly to obtain a polymer / nanomaterial modified composite agent; The preparation steps of the formulation modifier are as follows: S11: Add lanthanum sulfate to the chitosan solution at a weight ratio of 1:5, then add 2-5% of the total lanthanum sulfate in phosphate buffer solution and stir until homogeneous; S12: Add hydroxyapatite to 5-10 times its volume of sodium alginate solution, stir to disperse evenly, then wash with water and dry; S13: Add the S12-treated hydroxyapatite to the S11 product at a weight ratio of 1:5, stir and mix thoroughly to obtain the formulation modifier; The modified nano-bentonite is prepared as follows: Nano-bentonite is fed into a calcining furnace and calcined for 20-30 minutes at a temperature of 350-450℃. Then, the temperature is reduced to 35-45℃ at a rate of 2-5℃ / min. Next, it is added to 3-5 times its volume of deionized water and stirred until evenly dispersed. Finally, it is washed with water and dried to obtain the modified nano-bentonite. The modification treatment solution comprises the following raw materials in parts by weight: Sodium dodecyl sulfate 3-6 parts, water 45-55 parts, silane coupling agent KH560 1-3 parts, hydrochloric acid solution with a mass fraction of 3-6% 2-6 parts.

2. The polymer / nanomaterial composite filter membrane according to claim 1, characterized in that, The hydrochloric acid solution has a mass fraction of 5-10%.

3. The polymer / nanomaterial composite filter membrane according to claim 1, characterized in that, The curing and film-forming technology is as follows: the polymer / nanomaterial modified composite agent is sprayed into a tubular liquid film through a spinneret. After passing through an air gap of 6-8 cm, the liquid film enters a water bath at 20°C and is cured into a nanofiber film. Then, it is soaked and washed in water at 25°C for 2 days and dried. Finally, the nanofiber film is bonded to the treated and modified nonwoven fabric base layer with an adhesive, and a nanofiber film layer is finally formed on the surface of the nonwoven fabric base layer.

4. The polymer / nanomaterial composite filter membrane according to claim 1, characterized in that, The polymer material is polyacrylonitrile; the solvent is N,N-dimethylacetamide; and the thermoplastic resin is PE-polyethylene.

5. The polymer / nanomaterial composite filter membrane according to claim 1, characterized in that, The pH of the phosphate buffer solution is 5.0-6.0; the mass fraction of the chitosan solution is 10-20%; and the mass fraction of the sodium alginate solution is 10-20%.

6. A method for preparing a polymer / nanomaterial composite filter membrane as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Soak the non-woven fabric base layer in hydrochloric acid solution at a temperature of 35-38℃ for 1-2 hours, then remove, wash with water, and air dry. Step 2: The polymer / nanomaterial modifier is cured and film-forming agent to form a nanofiber film on the surface of the modified nonwoven fabric substrate; the diameter of the nanofiber film is 1-2 micrometers. Step 3: Finally, ultrasonically treat the modified solution with a power of 100-200W, a treatment time of 10-20 minutes, and a treatment temperature of 35-40℃. After treatment, wash with water and dry. Step 4: Finally, treat under a pressure of 10-15 MPa for 5-10 minutes to obtain the composite filter membrane.

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