Nano-catalysis antibacterial filter material for direct water dispenser and preparation method of nano-catalysis antibacterial filter material

Abstract

The invention relates to the technical field of water treatment materials, and discloses a nano-catalytic antibacterial filter material for a direct water dispenser, which comprises the following components in percentage by mass: 8-20% of broad-spectrum nano-antibacterial component, 55-85% of base material, 4-10% of binder, 2-5% of dispersant and 2-6% of assistant, the broad-spectrum nano antibacterial component is Ag-TiO / ZnO-CuO quaternary composite nanoparticles, and the mass ratio of Ag to TiO to ZnO to CuO is 1: (2-4): (1-3): (0.5-1.5). According to the nano catalytic antibacterial filter material and the preparation method thereof, the inhibition and killing rates on gram-negative bacteria (escherichia coli, pseudomonas aeruginosa and klebsiella pneumoniae), gram-positive bacteria (staphylococcus aureus, bacillus subtilis and methicillin-resistant staphylococcus aureus) and fungi (candida albicans and aspergillus niger) are all greater than or equal to 99.9%.

Description

Technical Field

[0001] This invention relates to the field of water treatment materials technology, specifically to a nano-catalytic antibacterial filter material for direct drinking water machines and its preparation method. Background Technology

[0002] As a point-of-use drinking water purification device, the antibacterial properties of the core filter media in a direct drinking water purifier directly affect the safety and hygiene of the output water. With increasing public health awareness, the potential presence of pathogenic bacteria in drinking water (such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Candida albicans, methicillin-resistant Staphylococcus aureus, and Aspergillus niger) has become a focus of attention. However, existing direct drinking water purifier filter media have significant limitations in antibacterial performance, mainly in the following aspects:

[0003] 1. Narrow antibacterial spectrum and single target: Existing filter media mostly rely on a single antibacterial component (such as silver ions, zinc oxide, quaternary ammonium salts, etc.), which has obvious selectivity in inhibiting pathogenic bacteria. For example, silver ions have a good inhibitory effect on Gram-negative bacteria (such as Escherichia coli), but the antibacterial rate of Gram-positive bacteria (such as Staphylococcus aureus) is usually only 85%-90%; zinc oxide is effective against some bacteria, but the inhibition rate of fungi (such as Candida albicans) is less than 70%; traditional activated carbon adsorption filter media can only achieve physical interception of bacteria, but cannot kill them, which can easily lead to a breeding ground for bacteria inside the filter media and create a risk of secondary pollution.

[0004] 2. Weak ability to inhibit complex bacterial communities: Pathogenic bacteria in actual drinking water environments often exist in the form of mixed bacterial communities (such as simultaneous presence of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae). Existing filter media, due to their singular antibacterial mechanism, are unable to simultaneously and effectively inhibit multiple different types of pathogenic bacteria. Studies have shown that after 3 months of use, the overall antibacterial rate of traditional silver-loaded filter media against mixed bacterial communities drops to below 60%, posing a risk of secondary pollution.

[0005] 3. Conflict between antibacterial durability and broad spectrum: Some improved filter media attempt to broaden the antibacterial spectrum by increasing the amount of antibacterial agent, but this leads to easy shedding of antibacterial components (shedding rate > 5%), which not only shortens the service life (usually < 3 months) but may also cause heavy metal leaching (such as silver ion leaching amount > 0.01 mg / L), which clearly violates the mandatory requirements of GB5749-2022 "Standards for Drinking Water Quality".

[0006] 4. Lack of synergistic antibacterial design: Existing technologies do not fully utilize the synergistic effect of different antibacterial components. For example, the rapid sterilization of metal ions and the long-term catalytic antibacterial effect of semiconductor nanomaterials do not complement each other, resulting in minimal inhibitory effect on stubborn pathogens (such as methicillin-resistant Staphylococcus aureus), making it difficult to meet the safety requirements of complex drinking water scenarios such as campuses and offices.

[0007] Therefore, developing a nano-catalytic filter material that can simultaneously and efficiently inhibit multiple pathogenic bacteria such as Gram-positive bacteria, Gram-negative bacteria, and fungi, and has a broad antibacterial spectrum, strong durability, and no secondary pollution, has become the key to solving the drinking water safety problem of direct drinking water machines, and has important industrial value and significance for people's livelihood. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] To address the shortcomings of existing technologies, this invention provides a nano-catalytic antibacterial filter material for direct drinking water machines and its preparation method, thus solving the aforementioned problems.

[0010] (II) Technical Solution

[0011] To achieve the above objectives, the present invention provides the following technical solution: a nano-catalytic antibacterial filter material for direct drinking water machines, comprising, by weight percentage: 55-85% base material, 8-20% broad-spectrum nano-antibacterial component, 4-10% binder, 2-5% dispersant, and 2-6% additives;

[0012] The broad-spectrum antibacterial nanoparticle is an Ag-TiO2 / ZnO-CuO quaternary composite nanoparticle, wherein the mass ratio of Ag, TiO2, ZnO and CuO is 1:2-4:1-3:0.5-1.5.

[0013] Preferably, the substrate is selected from one or more composites of modified columnar activated carbon, porous ceramics, and molecular sieves;

[0014] The modified columnar activated carbon, after being refluxed with 10-15% nitric acid solution at 80°C for 2-3 hours, has a specific surface area ≥1000m² / g, which can significantly enhance the adsorption performance of the substrate and the loading capacity of antibacterial components.

[0015] Preferably, the adhesive is selected from γ-aminopropyltriethoxysilane (KH550), waterborne polyurethane, or a mixture of both in a 1:1 ratio.

[0016] Preferably, the dispersant is selected from polyvinylpyrrolidone (PVP) and trisodium citrate.

[0017] Preferably, the additive is selected from nano-hydroxyapatite and attapulgite.

[0018] Preferably, the filter media has an antibacterial rate of ≥99.9% against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans, and can effectively cover more than 20 common pathogenic bacteria in drinking water.

[0019] Preferably, the antibacterial component has a shedding rate of ≤0.05%, and after 18 months of continuous use, the antibacterial rate against mixed microorganisms is still ≥99.5%, and the service life is 3-5 times longer than that of traditional silver-loaded filter media.

[0020] Preferably, the total leaching amount of heavy metals Ag, Zn, and Cu is ≤0.0005 mg / L, and the removal rate of phenol in water is ≥90%.

[0021] A method for preparing nano-catalytic antibacterial filter media for direct drinking water machines includes the following steps:

[0022] S1. Substrate pretreatment: The substrate is dried after treatment. Modified columnar activated carbon needs to be oxidized with nitric acid, and porous ceramics need to be treated with hydrofluoric acid.

[0023] S2. Preparation of broad-spectrum nano antibacterial components: Disperse TiO2 in water, add silver nitrate, zinc nitrate and copper nitrate solutions, adjust the pH to 7.5-8.5, react at 50-80℃ for 3-4 hours, dry and calcine at 500-600℃ for 2-3 hours;

[0024] S3. Loading treatment: Mix the substrate with nano antibacterial components, binder, dispersant and additives to form a slurry, ultrasonically disperse for 90 minutes, vacuum impregnate and lift 3-4 times, lifting speed 3-8mm / s;

[0025] S4. Curing and molding: Pre-baking at 90-110℃ for 2-3 hours, sintering at 400-500℃ for 3-4 hours under nitrogen protection, and then cooling to obtain the finished product.

[0026] Preferably, the ultrasonic dispersion power in step 2 is 300W, the ultrasonic dispersion power in step 3 is 500W, and the vacuum degree of vacuum impregnation is -0.08MPa.

[0027] (III) Broad-spectrum antibacterial mechanism

[0028] This invention constructs a multi-mechanism antibacterial system through the synergistic effect of Ag-TiO2 / ZnO-CuO quaternary composite nanocomponents, significantly broadening the antibacterial spectrum and improving antibacterial efficiency. The specific mechanism is as follows:

[0029] 1. Ag⁺ release mechanism: The Ag component in Ag-TiO2 / ZnO-CuO composite nanoparticles can slowly release Ag⁺. Ag⁺ penetrates the bacterial cell membrane, disrupts cell membrane permeability, and causes intracellular substances to leak out of the bacteria, thereby achieving rapid killing of Gram-negative bacteria (such as Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae).

[0030] 2. Dual antibacterial mechanism of ZnO: On the one hand, ZnO releases Zn²⁺ which binds to bacterial enzyme proteins and inhibits enzyme activity. On the other hand, it generates reactive oxygen species (ROS) in the aquatic environment, which oxidize and destroy the bacterial cell structure. This makes it particularly effective against Gram-positive bacteria (such as Staphylococcus aureus and Bacillus subtilis) and some fungi (such as Candida albicans).

[0031] 3. Photocatalytic antibacterial mechanism of TiO2: As a semiconductor nanomaterial, TiO2 catalyzes the generation of hydroxyl radicals (・OH) under visible or ultraviolet light irradiation. Hydroxyl radicals have extremely strong oxidizing power and can oxidize and degrade the proteins and nucleic acids of bacteria and fungi. In particular, this effect has a significant inhibitory effect on drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus.

[0032] 4. CuO-targeted antibacterial mechanism: Cu²⁺ released by CuO destroys the fungal cell wall through chelation, effectively compensating for the deficiency of single antibacterial components in inhibiting fungi, and achieving a highly efficient killing effect on fungi such as Aspergillus niger.

[0033] Through the synergistic effect described above, the quaternary components form a broad-spectrum antibacterial system covering more than 20 common pathogenic bacteria, including Gram-positive bacteria, Gram-negative bacteria, and fungi, thus completely solving the technical problem of selective antibacterial properties in existing filter media.

[0034] (iv) Beneficial effects

[0035] Compared with the prior art, the present invention provides a nano-catalytic antibacterial filter material for direct drinking water machines and its preparation method, which has the following beneficial effects:

[0036] 1. Broad antibacterial spectrum and high efficiency: The nano-catalytic antibacterial filter material and its preparation method used in direct drinking water machines have an antibacterial rate of ≥99.9% against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae), Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, methicillin-resistant Staphylococcus aureus), and fungi (Candida albicans, Aspergillus niger). It covers more than 20 common pathogenic bacteria in drinking water. Under the synergistic effect of the four components, the antibacterial rate is 3 times higher than that of single silver ion filter material, and the killing time of Escherichia coli is shortened from 6 hours to 2 hours, thus improving the water purification speed.

[0037] 2. Long service life: The nano-catalytic antibacterial filter material and its preparation method used in direct drinking water machines are fixed by chemical bonding and sintering. The antibacterial component shedding rate is ≤0.05%. After 18 months of continuous use, the antibacterial rate against mixed bacteria is still ≥99.5%. The service life is 3-5 times that of traditional filter materials.

[0038] 3. High safety and no secondary pollution: The nano-catalytic antibacterial filter material used in direct drinking water machines and its preparation method have a total leaching of heavy metals (Ag, Zn, Cu) of ≤0.0005mg / L, which is far below the national standard limit (0.01mg / L) and has no secondary pollution.

[0039] 4. Comprehensive water purification function: The photocatalytic effect of TiO2 can degrade trace organic matter in water (such as chloroform and phenol) with a removal rate of ≥90%. While antibacterial, it can also achieve deep purification of water quality and improve the taste and quality of the water.

[0040] 5. Stable and controllable preparation process: The preparation method has a clear process flow and well-defined process parameters. The optimized combination of processes such as ultrasonic dispersion, vacuum impregnation-pulling, and nitrogen-protected sintering ensures stable and uniform filter material performance, making it suitable for large-scale industrial production. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] A nano-catalytic antibacterial filter material for direct drinking water machines comprises, by weight percentage: 55-85% base material, 8-20% broad-spectrum nano-antibacterial component, 4-10% binder, 2-5% dispersant, and 2-6% additives;

[0043] The broad-spectrum antibacterial nanoparticle is an Ag-TiO2 / ZnO-CuO quaternary composite nanoparticle, wherein the mass ratio of Ag, TiO2, ZnO, and CuO is 1:2-4:1-3:0.5-1.5;

[0044] The substrate comprises 55-85% (selected from one or more composites of modified columnar activated carbon, porous ceramics, and molecular sieves; wherein the modified columnar activated carbon is treated with nitric acid oxidation and has a specific surface area ≥1000m² / g to enhance adsorption and loading capacity).

[0045] Broad-spectrum antibacterial nanoparticles: 8-20% (Ag-TiO2 / ZnO-CuO quaternary composite nanoparticles, wherein the mass ratio of Ag, TiO2, ZnO, and CuO is 1:2-4:1-3:0.5-1.5).

[0046] Adhesive: 4-10% (selected from γ-aminopropyltriethoxysilane (KH550) and waterborne polyurethane, or a blend thereof, with the best bonding effect when the blending ratio is 1:1).

[0047] Dispersant: 2-5% (selected from polyvinylpyrrolidone (PVP) and trisodium citrate, to improve the uniformity of nanoparticle dispersion);

[0048] Additives: 2-6% (selected from nano hydroxyapatite and attapulgite, to enhance the bonding force between antibacterial components and the substrate and reduce the peeling rate);

[0049] Among them, broad-spectrum antibacterial mechanism

[0050] This invention broadens the antibacterial spectrum through the synergistic effect of quaternary composite nanocomponents, and the specific mechanism is as follows:

[0051] Ag⁺: Disrupts bacterial cell membrane permeability, rapidly killing Gram-negative bacteria (such as Escherichia coli and Pseudomonas aeruginosa).

[0052] ZnO: By releasing Zn²⁺ and reactive oxygen species (ROS), it targets Gram-positive bacteria (such as Staphylococcus aureus) and some fungi (such as Candida albicans).

[0053] TiO2: Catalyzes the generation of hydroxyl radicals (・OH) under visible / ultraviolet light, which oxidize and degrade bacterial proteins, enhancing the inhibition of drug-resistant bacteria;

[0054] CuO: It destroys the fungal cell wall through the chelation of Cu²⁺, making up for the deficiency of single components in inhibiting fungi.

[0055] The synergistic effect of the four components provides an antibacterial spectrum covering more than 20 common pathogenic bacteria, including Gram-positive bacteria, Gram-negative bacteria, and fungi, thus solving the problem of selective antibacterial activity of single components.

[0056] A method for preparing nano-catalytic antibacterial filter media for direct drinking water machines includes the following steps:

[0057] S1. Substrate pretreatment:

[0058] If it is columnar activated carbon: pulverize to 15-40 mesh, reflux with 10-15% nitric acid solution at 80℃ for 2-3 hours, rinse with distilled water until pH 6.5-7.5, and vacuum dry at 110℃ for 4 hours to obtain modified activated carbon with a surface rich in carboxyl / hydroxyl groups;

[0059] For porous ceramics: Soak in 5% hydrofluoric acid solution for 1 hour to remove surface impurities, rinse with distilled water and dry at 120℃ for later use.

[0060] S2. Preparation of broad-spectrum nano-antibacterial components:

[0061] TiO2 powder (average particle size 20-30 nm) was dispersed in deionized water, magnetically stirred for 30 minutes, and then ultrasonically dispersed (power 300 W) for 60 minutes to obtain a TiO2 suspension.

[0062] Add silver nitrate solution (0.1 mol / L), zinc nitrate solution (0.2 mol / L), and copper nitrate solution (0.05 mol / L) in the specified proportions, stir well, and then adjust the pH to 7.5-8.5 with 1 mol / L sodium hydroxide solution.

[0063] Transfer to a water bath and stir at 60-80℃ for 3-4 hours to generate Ag-TiO2 / ZnO-CuO composite nanoparticle precursor;

[0064] Centrifuge (8000 r / min, 15 minutes), wash the precipitate three times with deionized water, dry at 105℃ for 6 hours, then calcine in a muffle furnace at 500-600℃ for 2-3 hours (heating rate 5℃ / min), cool and grind through a 200-mesh sieve to obtain quaternary composite nano antibacterial powder.

[0065] S3, Load Handling:

[0066] The pretreated substrate, nano-antibacterial components, binder, dispersant, and additives are mixed in proportion, and deionized water is added (solid-liquid ratio 1:3), and stirred to form a uniform slurry.

[0067] Ultrasonic dispersion (500W power) for 90 minutes to ensure uniform dispersion of nanoparticles;

[0068] Vacuum impregnation-lift loading method: The substrate is placed in the slurry and impregnated for 30 minutes under a vacuum of -0.08MPa. Then, it is lifted at a speed of 3-8mm / s. The impregnation-lifting process is repeated 3-4 times to ensure that the antibacterial components are evenly coated on the surface and pores of the substrate.

[0069] S4, Curing and Molding:

[0070] After loading, the substrate is pre-dried in a 90-110℃ forced-air drying oven for 2-3 hours to remove surface moisture;

[0071] Transfer to a tube furnace and sinter at 400-500℃ for 3-4 hours under nitrogen protection (flow rate 200mL / min) to ensure that the antibacterial components are firmly bonded to the substrate through chemical bonding (such as Si-OC bond, metal-oxygen bond);

[0072] When naturally cooled to room temperature, a broad-spectrum antibacterial nanocatalytic filter material is obtained.

[0073] The filter media obtained through the above steps has an antibacterial rate of ≥99.9% against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae), Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, methicillin-resistant Staphylococcus aureus), and fungi (Candida albicans, Aspergillus niger), covering more than 20 common pathogenic bacteria in drinking water;

[0074] The synergistic effect of the quaternary components increases the antibacterial rate by 3 times compared to single silver ion filter media (reducing the killing time of E. coli from 6 hours to 2 hours).

[0075] Through chemical bonding and sintering fixation, the antibacterial component shedding rate is ≤0.05%, and the antibacterial rate against mixed bacteria is still ≥99.5% after 18 months of continuous use. Its service life is 3-5 times that of traditional filter media.

[0076] The total leaching of heavy metals (Ag, Zn, Cu) is ≤0.0005mg / L, which is far below the national standard limit (0.01mg / L). There is no secondary pollution. The photocatalytic effect of TiO2 can degrade trace organic matter in water (such as chloroform and phenol) with a removal rate of ≥90%, thus improving the quality of the effluent.

[0077] Example 1:

[0078] S1. Substrate pretreatment: Take 65 parts by weight of columnar activated carbon, pulverize it to 20-30 mesh, reflux it with 12% nitric acid solution at 80℃ for 2.5 hours, rinse it with distilled water until pH 7.0, and vacuum dry it at 110℃ for 4 hours to obtain modified activated carbon.

[0079] S2. Preparation of nano-antibacterial components: 4 parts by weight of TiO2 (particle size 25nm) were dispersed in deionized water and ultrasonically dispersed for 60 minutes. 1 part by weight of silver nitrate solution, 3 parts by weight of zinc nitrate solution, and 1 part by weight of copper nitrate solution were added. The pH was adjusted to 8.0, and the mixture was stirred at 70℃ for 3.5 hours. After centrifugation, the mixture was dried at 105℃ for 6 hours and calcined at 550℃ for 2.5 hours to obtain Ag-TiO2 / ZnO-CuO composite nanopowder (total 9 parts by weight).

[0080] S3. Loading treatment: Mix modified activated carbon with 9 parts by weight of composite nanopowder, 6 parts by weight of KH550 binder, 3 parts by weight of PVP dispersant, and 4 parts by weight of nano hydroxyapatite additive, add deionized water to make slurry, ultrasonically disperse for 90 minutes, vacuum impregnate (-0.08MPa) for 30 minutes, and then pull at a speed of 5mm / s. Repeat 4 times.

[0081] S4. Curing and molding: Pre-baking at 100℃ for 2.5 hours, sintering at 450℃ for 3.5 hours under nitrogen protection, and then cooling to obtain the target filter material.

[0082] Example 2:

[0083] S1. Substrate pretreatment: Mix 50 parts by weight of porous ceramic (30 mesh) with 20 parts by weight of molecular sieve (20 mesh), soak in 5% hydrofluoric acid for 1 hour, rinse and dry at 120℃.

[0084] S2. Preparation of nano antibacterial components: Same as in Example 1, take 12 parts by weight of composite nano powder (Ag:TiO2:ZnO:CuO=1:3:2:1).

[0085] S3. Loading treatment: Add 8 parts by weight of water-based polyurethane adhesive, 4 parts by weight of trisodium citrate, and 5 parts by weight of attapulgite clay. The remaining steps are the same as in Example 1.

[0086] S4. Curing and molding: Pre-dry at 110℃ for 2 hours, sinter at 480℃ for 3 hours to obtain the target filter material.

[0087] Comparative Examples (Prior Art)

[0088] Comparative Sample 1: Single silver ion supported activated carbon (silver content 5%).

[0089] Comparative Sample 2: TiO2-ZnO composite filter media (without Ag and CuO);

[0090] Comparison Sample 3: Commercially available antibacterial filter media for direct drinking water machines (claiming an antibacterial rate of 99%);

[0091] Test items (%) Example 1 Example 2 Comparison Sample 1 Comparison Sample 2 Comparison Sample 3 Escherichia coli antibacterial rate 99.99 99.98 99.50 98.20 99.00 Staphylococcus aureus antibacterial rate 99.97 99.96 88.30 99.20 95.50 Antibacterial rate of Pseudomonas aeruginosa 99.96 99.95 99.10 97.80 96.20 Antibacterial rate of Candida albicans 99.95 99.94 65.20 82.50 78.30 Antibacterial rate after 18 months 99.60 99.50 58.70 72.30 65.10 Heavy metal leaching amount (mg / L) 0.0003 0.0004 0.012 0.005 0.008 Phenol removal rate 92.5 91.8 12.3 85.6 25.7

[0092] Test methods: Antibacterial rate according to GB / T21510-2008 "Test Method for Antibacterial Performance of Nano-Inorganic Materials"; Heavy metal leaching according to GB5749-2022; Organic matter removal rate according to HJ503-2009 "Determination of Volatile Phenols in Water".

[0093] Test results show that the antibacterial rate of the filter material of the present invention against Gram-negative bacteria, Gram-positive bacteria and fungi is significantly higher than that against the control sample, and its performance remains stable after long-term use, fully demonstrating its broad-spectrum antibacterial advantage.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A nano-catalytic antibacterial filter material for direct drinking water machines, characterized in that: By weight percentage: 55-85% base material, 8-20% broad-spectrum nano antibacterial component, 4-10% binder, 2-5% dispersant, and 2-6% additives; The broad-spectrum antibacterial nanoparticle is an Ag-TiO2 / ZnO-CuO quaternary composite nanoparticle, wherein the mass ratio of Ag, TiO2, ZnO and CuO is 1:2-4:1-3:0.5-1.

5.

2. The nano-catalytic antibacterial filter material for direct drinking water machines and its preparation method according to claim 1, characterized in that: The substrate is selected from one or more composites of modified columnar activated carbon, porous ceramics, and molecular sieves; The modified columnar activated carbon, after being refluxed with 10-15% nitric acid solution at 80°C for 2-3 hours, has a specific surface area ≥1000m² / g.

3. The nano-catalytic antibacterial filter material for direct drinking water machines according to claim 1, characterized in that: The adhesive is selected from one or a 1:1 mixture of γ-aminopropyltriethoxysilane (KH550) and waterborne polyurethane.

4. The nano-catalytic antibacterial filter material for direct drinking water machines according to claim 1, characterized in that: The dispersant is selected from one of polyvinylpyrrolidone (PVP) and trisodium citrate.

5. The nano-catalytic antibacterial filter material for direct drinking water machines according to claim 1, characterized in that: The additive is selected from nano-hydroxyapatite and attapulgite.

6. The nano-catalytic antibacterial filter material for a direct drinking water machine according to claim 1, characterized in that: The filter media has an antibacterial rate of ≥99.9% against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans.

7. The nano-catalytic antibacterial filter material for a direct drinking water machine according to claim 1, characterized in that: The antibacterial component has a shedding rate of ≤0.05%, and its antibacterial rate against mixed microbial flora remains ≥99.5% after 18 months of continuous use.

8. The nano-catalytic antibacterial filter material for a direct drinking water machine according to claim 1, characterized in that: The total leaching amount of heavy metals Ag, Zn, and Cu is ≤0.0005 mg / L, and the removal rate of phenol in water is ≥90%.

9. A method for preparing nano-catalytic antibacterial filter material for direct drinking water machines according to claim 1, comprising the following steps: S1. Substrate pretreatment: The substrate is dried after treatment. Modified columnar activated carbon needs to be oxidized with nitric acid, and porous ceramics need to be treated with hydrofluoric acid. S2. Preparation of broad-spectrum nano antibacterial components: Disperse TiO2 in water, add silver nitrate, zinc nitrate and copper nitrate solutions, adjust the pH to 7.5-8.5, react at 50-80℃ for 3-4 hours, dry and calcine at 500-600℃ for 2-3 hours; S3. Loading treatment: Mix the substrate with nano antibacterial components, binder, dispersant and additives to form a slurry, ultrasonically disperse for 90 minutes, vacuum impregnate and lift 3-4 times, lifting speed 3-8mm / s; S4. Curing and molding: Pre-baking at 90-110℃ for 2-3 hours, sintering at 400-500℃ for 3-4 hours under nitrogen protection, and then cooling to obtain the finished product.

10. The method for preparing nano-catalytic antibacterial filter material for direct drinking water machines according to claim 1, characterized in that: The ultrasonic dispersion power in step 2 is 300W, the ultrasonic dispersion power in step 3 is 500W, and the vacuum degree of vacuum impregnation is -0.08MPa.