Ultrafiltration membrane for removing viruses and bacteria, and manufacturing method therefor

Abstract

The present invention relates to an ultrafiltration membrane for removing viruses and bacteria, and a manufacturing method therefor, and, more specifically, to an ultrafiltration membrane for removing viruses and bacteria, comprising: (a) a porous polymer support membrane; and (b) a cross-linked and positively-charged coating layer formed on both the internal pores and the surface of the porous polymer support membrane. The ultrafiltration membrane has excellent disinfection and turbidity removal performance and can be applied as a viral and bacterial filter.

Description

Ultrafiltration membrane for removing viruses and bacteria and method for manufacturing the same

[0001] The present invention relates to an ultrafiltration membrane for removing viruses and bacteria and a method for manufacturing the same, and more particularly, to a technology for improving sterilization and turbidity removal performance by coating a positively charged substance on the pores and surface of a porous polymer separation membrane to impart a positive charge to the membrane, and applying the same to a microbial filter such as a virus or bacteria.

[0002] Membranes are used as filtration membranes in various fields such as water treatment, such as beverage manufacturing, water purification, and wastewater treatment, and the food industry, and are classified into reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), and microfiltration (MF).

[0003] The primary mechanism for membrane contaminant removal is the sieve effect, which removes particles based on their size and can remove bacteria, viruses, and organic contaminants suspended in water. Membranes include flat and hollow fiber membranes, with hollow fiber membranes known to offer greater effective surface area for water treatment than flat membranes.

[0004] In addition to removal by particle size, a method of filtering microorganisms in water by electrostatic adsorption according to the surface charge of the membrane has also been proposed. This method is being studied and is receiving attention due to its high permeability and particle removal performance compared to low operating pressure.

[0005] Although polymer membranes are used in various fields, for example, in water treatment fields such as water purification and wastewater treatment, the amount of water to be filtered is large, so there is a need to further improve water permeability during filtration.

[0006] [Prior Art Literature]

[0007] [Patent Document]

[0008] (Patent Document 1) Korean Patent Publication No. 10-2024-0016601

[0009] (Patent Document 2) Korean Patent No. 10-1283738

[0010] (Patent Document 3) Korean Patent No. 10-1077954

[0011] The purpose of the present invention is to provide an ultrafiltration membrane having improved water permeability and microbial removal rate by manufacturing a porous polymer membrane having a positive charge.

[0012] In order to achieve the above object, the present invention provides an ultrafiltration membrane for removing viruses and bacteria, comprising: (a) a porous polymer support membrane; and (b) a positively charged coating layer having a cross-linked structure formed on both the internal pores and the surface of the porous polymer support membrane.

[0013] The ultrafiltration membrane according to the present invention can provide a separation membrane with excellent performance, having a virus removal rate of 99.9% or higher, a sterilization performance of 99.99% or higher, a bacteria removal rate of 99.99% or higher, and a turbidity removal performance of 0.1 NTU or lower.

[0014] In addition, the lifespan of the membrane is greatly improved, so that the sterilization and turbidity removal performance does not deteriorate even after long-term use.

[0015] However, the effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0016] Figure 1 shows images of the cross-section (left) and surface (right) of an ultrafiltration membrane manufactured according to Example 1 of the present invention, analyzed by SEM.

[0017] Figure 2 shows images of the cross-section (left) and surface (right) of an ultrafiltration membrane manufactured according to Example 2 of the present invention, analyzed by SEM.

[0018] Figure 3 shows images of the cross-section (left) and surface (right) of an ultrafiltration membrane manufactured according to Comparative Example 1 of the present invention, analyzed by SEM.

[0019] Figure 4 shows images of the cross-section (left) and surface (right) of an ultrafiltration membrane manufactured according to Comparative Example 2 of the present invention, analyzed by SEM.

[0020] Hereinafter, the present invention will be described in detail with reference to the attached drawings.

[0021]

[0022] One aspect of the present invention relates to an ultrafiltration membrane including a positively charged coating layer formed by coating positive charges on the surface and internal pores of a porous polymer membrane, and can implement a water treatment filter having excellent adsorption and removal performance.

[0023] Specifically, the present invention relates to an ultrafiltration membrane for removing viruses and bacteria, comprising: (a) a porous polymer support membrane; and (b) a positively charged coating layer having a cross-linked structure formed on both the internal pores and the surface of the porous polymer support membrane.

[0024] At this time, the ultrafiltration membrane may be in the form of a flat membrane or a hollow fiber membrane.

[0025] Additionally, the positively charged coating layer may be at least one positively charged material selected from the group consisting of a multifunctional amine compound, chitosan, melamine, and mixtures thereof.

[0026] In addition, the positively charged material may be a compound that does not affect the properties of the ultrafiltration membrane. One of them, a polyfunctional amine compound, may be at least one selected from the group consisting of polyethyleneimine, diethylenetriamine, piperazine, dimethylenepiperazine, and diphenylamine. Most preferably, polyethyleneimine, which has a high positive charge density and thus readily reacts with a crosslinking agent to impart a positive charge, may be used.

[0027] At this time, the weight average molecular weight of the polyfunctional amine compound may be 1,000-1,000,000, and preferably 2,000-700,000. If the weight average molecular weight of the polyfunctional amine compound is less than 1,000, a problem of elution due to water pressure may occur due to durability issues, and if the weight average molecular weight of the polyfunctional amine compound exceeds 1,000,000, a uniformity of the coating may decrease due to increased viscosity, and a deviation in performance may occur due to decreased durability, which is not preferable.

[0028] In addition, chitosan, which is the positively charged substance, is a polymer made by deacetylating chitin. Chitin is a substance widely distributed in the shells of crustaceans and insects, and the cell walls of fungi such as molds and mushrooms, and is a natural polymer substance with a molecular weight of over 1 million and over 5,000 N-acetyl glucosamines combined.

[0029] In Korea, chitosan is recognized when the degree of deacetylation is 70% or higher, and the amino group formed during the deacetylation process of chitosan makes it easily soluble in acid. In particular, the amino group (-NH2) present at the end of chitosan forms a trivalent ion (-NH3) that has antibacterial properties under acidic conditions. + ) has a characteristic of changing into a coating layer on the surface of the membrane.

[0030] In addition, the positively charged substance, melamine, has three amino groups that react with formaldehyde to form methylol groups, and these methylols can form thermosetting polymers through a condensation reaction. Melamine resin has high surface hardness and excellent heat resistance, chemical resistance, water resistance, and electrical properties, and its demand is increasing in adhesives, paints, molding materials, and decorative panels.

[0031]

[0032] In the ultrafiltration membrane according to the present invention, the porous polymer support membrane can be manufactured using at least one selected from the group consisting of polysulfone, polyethersulfone, polyvinylidene fluoride, polyacrylonitrile, polyimide, polyetherimide, and mixtures thereof.

[0033] Preferably, polysulfone, polyethersulfone and mixtures thereof can be used, and most preferably, polysulfone can be used.

[0034] Polysulfone resins offer excellent chemical and heat resistance, a wide pH range, and excellent solubility in organic solvents, making it easy to prepare dope solutions. Furthermore, their high inter-polymer chain attractive force increases the strength of the polymer support, making them desirable.

[0035]

[0036] The ultrafiltration membrane according to the present invention may have a surface charge of 5-40 mV at a pH of 7 due to a positively charged coating layer, and more preferably, a surface charge of 15-40 mV. In this way, since the surface charge of the separation membrane exhibits a positive charge, it may have the ability to adsorb and capture organic substances or particles having a negative charge.

[0037] At this time, if the surface charge is less than 5 mV, there may be a problem of reduced adsorption capacity for viruses and other organic substances, and if it exceeds 40 mV, the virus adsorption capacity may be maintained above a certain level, but the production cost increases due to the reaction time and increased concentration to exhibit a high surface charge during the manufacturing process, which may be unfavorable in terms of economic feasibility.

[0038]

[0039] The ultrafiltration membrane according to the present invention may have an average pore size of 0.01-1 μm, and more preferably, an average pore size of 0.1-0.5 μm.

[0040] If the average pore size is less than 0.01 μm, the pores become too small, which causes a significant decrease in flow rate, and if it exceeds 1 μm, the pores become too large, which causes a decrease in removal performance for viruses and organic compounds, which is not desirable.

[0041]

[0042] The ultrafiltration membrane according to the present invention may have an average thickness of 50-200 μm, and more preferably, a thickness of 100-150 μm. If the thickness of the ultrafiltration membrane is less than 50 μm, the membrane may not be formed sufficiently thick, and thus the membrane may be destroyed or damaged due to the rapid flow rate of the permeate. If the thickness exceeds 200 μm, the processability of the membrane may be reduced, and there may be problems in terms of durability and safety, such as a reduced service life due to differential pressure generation.

[0043] In addition, the positively charged coating layer may be formed with an average thickness of 0.01-3 μm, and more preferably, may be formed with a thickness of 0.05-1 μm. If the average thickness is less than 0.01 μm, there may be a problem of deviation in physical properties due to a decrease in the uniformity of the coating layer, and if the average thickness exceeds 3 μm, there is no increase in the virus removal effect due to a further increase in the coating layer thickness, which is not desirable from an economic perspective.

[0044]

[0045] The cross-sectional structure of the ultrafiltration membrane according to the present invention may be a sponge-shaped structure. In general, the cross-sections of separation membranes for water treatment can be broadly divided into a finger-like structure and a sponge-like structure.

[0046] The finger structure has a dense outermost layer, which significantly reduces water permeability. This is because, since pores are not formed, the solvent remaining in the cross-section dissolves the polymer, forming large pores in the cross-section, weakening the pressure resistance and preventing the membrane from functioning as a separation membrane when the outer surface leaks.

[0047] Sponge structures can be divided into symmetric membrane structures and asymmetric membrane structures. The symmetric membrane structure is a structure in which the pore sizes of the outer and inner surfaces are the same, and the asymmetric membrane structure can be defined as a structure in which the pore sizes of the outer and inner surfaces are different. The asymmetric membrane has the advantage of lower flow resistance and higher water permeation efficiency compared to the symmetric membrane. In addition, the cross-sectional structure is formed into a more compact structure than the finger structure, so it has superior pressure resistance and durability.

[0048] Therefore, it is more desirable to have a cross-sectional structure of a sponge structure in terms of water permeation efficiency and mechanical strength of the separation membrane.

[0049]

[0050] Another aspect of the present invention relates to a method for manufacturing an ultrafiltration membrane for removing viruses and bacteria.

[0051] Specifically, the method may include: (A) a step of preparing a porous polymer support membrane; (B) a step of coating the porous polymer support membrane by placing it in a solution of a positively charged substance and immersing it in an oven at 50 to 60°C for 1 to 4 hours; (C) a step of washing the polymer support membrane coated with the positively charged substance obtained in step (B) and then immersing it in a crosslinking agent aqueous solution at 15 to 30°C for 5 minutes to 1 hour.

[0052]

[0053] Step (A) of the present invention is a step for manufacturing a porous polymer membrane, and is not particularly limited as long as it is a method commonly used in the field. For example, a roll-to-roll process, NIPS method, TIPS method, etc. can be used.

[0054] According to a preferred embodiment of the present invention, a porous separation membrane in the form of a hollow fiber can be obtained by dissolving a polymer in an organic solvent, dissolving the polymer in an organic solvent, and dispersing the internal coagulant into the air through a double tubular nozzle, and then solidifying it with an external coagulant to cause a phase transition.

[0055] The organic solvent for dissolving the polymer is not particularly limited as long as it is a solvent commonly used in the field, but preferably, it may be at least one selected from the group consisting of N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethanol, water, and mixtures thereof, which are solvents having a high boiling point, and more preferably, NMP or DMAc may be used.

[0056] In addition, a hydrophilic additive may be additionally included to control the viscosity of the above-mentioned radiation source or to control the pore size of the polymer support membrane. The hydrophilic additive may be at least one selected from the group consisting of polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, and mixtures thereof.

[0057]

[0058] Step (B) of the present invention is a step of coating a positively charged polymer, and can be performed using a general coating method used in the art, such as dip coating or spray coating.

[0059] According to a preferred embodiment of the present invention, the support obtained in step (A) can be coated by immersing it in a positively charged substance solution, and it is preferable to coat it by immersing it in an oven at 50-60°C for 1-4 hours.

[0060] At this time, the positively charged substance solution may contain 1-20 wt% of the positively charged substance and the remainder of the solvent. If the positively charged substance is less than 1 wt%, the positively charged coating layer becomes thin, which is problematic in that the strength is weakened. If it exceeds 20 wt%, the viscosity increases excessively, which is undesirable in that the coating becomes difficult.

[0061] In addition, the solvent of the positively charged substance solution is not particularly limited as long as it is a solvent commonly used in the field, but preferably, it may be at least one selected from the group consisting of N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethanol, water, and mixtures thereof, and more preferably, NMP or DMAc may be used.

[0062]

[0063] Step (C) of the present invention is a step of crosslinking a positively charged polymer, and the positively charged coating layer formed by immersing the porous polymer support membrane in a crosslinking agent aqueous solution can be crosslinked and fixed to the separation membrane.

[0064] At this time, it is preferable that the crosslinking agent aqueous solution be at a temperature of 15-30°C, and it is also preferable to immerse it for 5 minutes to 1 hour to allow sufficient time for crosslinking to increase the bonding strength of the coating layer.

[0065] At this time, the crosslinking agent aqueous solution may contain 0.5-5 wt% of crosslinking agent and the remainder of the solvent. If the crosslinking agent concentration is less than 0.5 wt%, there is a problem that the binding strength of the positively charged polymer is reduced, and even if it exceeds 5 wt%, the binding strength does not increase further as the crosslinking agent concentration increases, which may be unfavorable from an economic perspective.

[0066] In addition, the crosslinking agent may be at least one selected from the group consisting of glutaraldehyde, formaldehyde, and mixtures thereof, and most preferably glutaraldehyde.

[0067] The above cross-linking agent can not only act as a cross-linking agent and binder between positively charged polymers, but also serve to improve the adhesion between the separator and the positively charged coating layer.

[0068]

[0069] In addition, in the method for manufacturing an ultrafiltration membrane of the present invention, a heat treatment step at 40-120°C may be additionally included after step (C). The heat treatment is a process for fixing the crosslinked positively charged coating layer, and may be preferably performed at 50-100°C, more preferably at 60-100°C. If the temperature is less than 40°C, the coating layer may not be sufficiently fixed, and thus the removal ability against viruses and bacteria may not be exhibited. On the other hand, if the temperature exceeds 120°C, thermal deformation of the polymer support may occur, narrowing the pores and adversely affecting the water permeation amount, which is not preferable.

[0070]

[0071] Hereinafter, preferred embodiments are presented to aid understanding of the present invention. However, these embodiments are intended to illustrate the present invention more specifically, and the scope of the present invention is not limited thereby. It will be apparent to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present invention.

[0072]

[0073] Example

[0074] Example 1. Preparation of a polysulfone hollow fiber membrane with a sponge structure

[0075] 1-1) Porous hollow fiber membrane manufacturing step

[0076] A spinning solution is prepared by mixing 300 g of polysulfone polymer, 900 g of solvent (NMP), and 300 g of additive (PVP), and an internal coagulating solution is prepared by mixing 25 wt% of water and 75 wt% of NMP. The spinning solution and the internal coagulating solution are spun into the air using a double tubular nozzle, and then washed in an external coagulating tank while completely inverting the phase, and then wound and dried to obtain a porous hollow fiber membrane.

[0077]

[0078] 1-2) Positive charge coating stage

[0079] After washing the hollow fiber membrane obtained in step 1-1), it is placed in a 2 wt% aqueous solution of polyethyleneimine and immersed in an oven at 60°C for 2 hours. The immersed hollow fiber membrane is immersed in a 2 wt% aqueous solution of glutaraldehyde at 25°C for 30 minutes to form a coating layer having a crosslinked structure.

[0080]

[0081] Example 2. Preparation of a polyethersulfone hollow fiber membrane with a sponge structure

[0082] The method was the same as in Example 1, except that a spinning solution was prepared by mixing 300 g of polyethersulfone polymer, 900 g of solvent (NMP), and 300 g of additive (PVP) in step 1-1) of Example 1.

[0083]

[0084] Comparative Example 1. Preparation of a polysulfone hollow fiber membrane with a finger structure.

[0085] 1-1) Porous hollow fiber membrane manufacturing step

[0086] A spinning solution is prepared by mixing 300 g of polysulfone polymer, 900 g of solvent (DMF), and 300 g of additive (PVP), and an internal coagulating solution is prepared by mixing 25 wt% of water and 75 wt% of DMF (Dimethyl Formamide). The spinning solution and the internal coagulating solution are spun into the air using a double tubular nozzle, and then washed in an external coagulating tank while completely inverting the phase, and then wound and dried to obtain a porous hollow fiber membrane.

[0087]

[0088] 1-2) Positive charge coating stage

[0089] After washing the hollow fiber membrane obtained in step 1-1), it is placed in a 2 wt% aqueous solution of polyethyleneimine and immersed in an oven at 60°C for 2 hours. The immersed hollow fiber membrane is immersed in a 2 wt% aqueous solution of glutaraldehyde at 25°C for 30 minutes to form a coating layer having a crosslinked structure.

[0090]

[0091] Comparative Example 2. Preparation of a polyethersulfone hollow fiber membrane with a finger structure.

[0092] The spinning solution was prepared in the same manner as in Comparative Example 1, except that in step 1-1) of Comparative Example 1, 300 g of polyethersulfone polymer, 900 g of solvent (DMF), and 300 g of additive (PVP) were mixed.

[0093]

[0094] Experimental example

[0095] Experimental Example 1. Analysis of membrane characteristics before positive coating

[0096] The characteristics of ultrafiltration membranes manufactured according to the examples and comparative examples of the present invention were analyzed. The water permeability and turbidity of the porous hollow fiber membranes before positive charge coating, i.e., before performing the positive charge coating step of the above examples, were measured and are shown in Table 1 below.

[0097] Water permeability measures the amount of ultrapure water passing through a unit area under a constant pressure. The ultrapure water was maintained at 25°C, and the measurement was performed under an ambient temperature of 25°C and a relative humidity of 50%. Water permeability is calculated using Equation 1 below.

[0098] [Calculation Formula 1]

[0099] Water permeability = permeation amount (L) / {membrane area (m) 2 ) × pressure (bar) × time (hr)}

[0100]

[0101] Turbidity refers to the degree of cloudiness of water due to suspended solids and other substances. It is a water quality indicator, usually expressed by optically measuring the degree to which light is scattered by suspended solids. The unit used to express turbidity is the Nephelo-metric Turbidity Unit (NTU), and the drinking water standard is set at 1 NTU or less.

[0102] Turbidity is measured using a turbidity meter. The temperature of a tungsten filament lamp is raised to 2200-2700K, and the light emitted is passed through the test sample, and the scattered light is measured at a 90° angle. The scattered light is measured at a distance of less than 10cm from the light source.

[0103] In Table 1 below, the turbidity removal rate represents the value calculated by the following calculation formula 2 from the turbidity of the raw water to the turbidity of the permeate.

[0104] [Calculation Formula 2]

[0105] Removal rate (%) = 1-(transmittance turbidity / original water turbidity) × 100

[0106]

[0107] Water permeability (L / m) 2 h) Turbidity Source water (NTU) Permeate water (NTU) Removal rate (%) PSf support 131301000.0899.92 PES support 129301000.0699.94 PSf support 215201000.0699.94 PES support 212601000.0799.93

[0108] The PSf (polysulfone) support and PES (polyethersulfone) support shown in Table 1 above refer to porous polymer supports that have not undergone a positive charge coating step. Polymer supports 1 and 2 were manufactured under different solvent conditions to confirm structural differences, and support 1 refers to a support with a sponge structure, and support 2 refers to a support with a finger structure.

[0109] As shown in Table 1 above, it can be confirmed that polymer membranes with a sponge structure exhibit higher water permeability and superior filtration effect compared to polymer membranes with a finger structure. In particular, the sponge-structured membrane manufactured using polysulfone polymer exhibited a water permeability of 3000 L / m 2 It can be seen that it is the best performing separation membrane that simultaneously exhibits high water permeability of more than h and high turbidity removal rate of more than 99.9%.

[0110]

[0111] Experimental Example 2. Characteristics of a Positively Charged Polymer Membrane

[0112] The characteristics of ultrafiltration membranes manufactured according to the Examples and Comparative Examples of the present invention after the positive charge coating step were analyzed. The water permeability, bacterial removal rate, virus removal rate, and turbidity of each membrane manufactured according to the Examples and Comparative Examples were measured and are shown in Table 2 below.

[0113] Virus removal ability is expressed in PFU / ml (PFU: plague forming units) at a static pressure of 1 bar, and bacteria removal ability is expressed in CFU / ml (CFU: colony forming unit) at a static pressure of 1 bar. RNA coliphage Qβ (ATCC23631-B1), a virus, was 2.6×10 5 PFU / ml, 1.8×10 of E. coli bacteria 6 CFU / ml and 1.8×10 of Staphylococcus aureus bacteria 6 The virus and bacteria removal performance was evaluated by permeating a solution containing CFU / ml.

[0114]

[0115] Water permeability (L / m2h) Bacteria removal rate (%) Virus removal rate (%) Turbidity Raw water (NTU) Permeate water (NTU) Removal rate (%) Example 12,82099.99% or more 99.9% 1000.0399.97 Example 22,53099.99% or more 99.9% 1000.0399.97 Comparative example 189099.99% or more 99.9% 1000.0399.97 Comparative example 256099.99% or more 99.9% 1000.0399.97

[0116] As shown in Table 2 above, it can be confirmed that the polymer membrane with a sponge structure coated with a positive charge manufactured according to an embodiment of the present invention exhibits both high water permeability and excellent bacteria and virus removal performance. In particular, it can be seen that the bacterial removal rate is excellent at 99.99% or higher in all examples, and the virus removal rate is excellent at 99.9% or higher.

[0117] Meanwhile, the polymer membrane with a finger structure coated with positive charges manufactured according to the comparative example of the present invention also showed excellent bacteria and virus removal performance of over 99.9%, but the water permeability was significantly lower at 1000 L / m than that of the example. 2 Since the value is below h, it can be seen that the finger-structured membrane is not desirable for application as a water filter.

[0118]

[0119] In addition, in order to analyze the surface and cross-sectional structure of the polymer hollow fiber membranes manufactured according to the examples and comparative examples of the present invention, SEM analysis was performed, and the results are shown in FIGS. 1 to 4. FIGS. 1 to 4 respectively show images obtained by analyzing Examples 1 and 2 and Comparative Examples 1 and 2 in that order. Referring to FIGS. 1 to 4, it can be confirmed that the cross-sectional structure of the polymer hollow fiber membranes manufactured according to the examples of the present invention has a sponge structure, pores are formed on the outer surface and the inner surface, the pore distribution is uniform, and the pore size is 0.1-0.4 μm on average.

[0120] On the other hand, it can be confirmed that the cross-sectional structure of the polymer hollow fiber membrane manufactured according to the comparative example has a finger structure, and the distribution of pores is not uniform compared to the example.

[0121] Therefore, the above experimental examples confirm that the positively charged polymer porous membrane manufactured according to the present invention not only exhibits excellent virus and bacteria removal performance but also exhibits high water permeability. Therefore, it is expected that this membrane can be effectively utilized in the water treatment industry by being applied to water treatment filters. Furthermore, it is expected that it can be utilized as an environmentally friendly filter that can replace existing glass fiber filters.

Claims

1. (a) porous polymer support membrane; and (b) An ultrafiltration membrane for removing viruses and bacteria, comprising a positively charged coating layer having a cross-linked structure formed on both the internal pores and the surface of the porous polymer support membrane.

2. An ultrafiltration membrane for removing viruses and bacteria, characterized in that the ultrafiltration membrane in the first paragraph is in the form of a flat membrane or a hollow fiber membrane.

3. In paragraph 1, An ultrafiltration membrane for removing viruses and bacteria, characterized in that the positively charged coating layer is at least one positively charged material selected from the group consisting of a multifunctional amine compound, chitosan, melamine, and mixtures thereof.

4. In paragraph 3, An ultrafiltration membrane for removing viruses and bacteria, characterized in that the above multifunctional amine compound is at least one selected from the group consisting of polyethyleneimine, diethylenetriamine, piperazine, dimethylenepiperazine, and diphenylamine.

5. In paragraph 1, An ultrafiltration membrane for removing viruses and bacteria, characterized in that the material of the porous polymer support membrane is at least one selected from the group consisting of polysulfone, polyethersulfone, polyvinylidene fluoride, polyacrylonitrile, polyimide, polyetherimide, and mixtures thereof.

6. In paragraph 1, The above ultrafiltration membrane is an ultrafiltration membrane for removing viruses and bacteria, characterized in that it has a surface charge of 5-40 mV.

7. In paragraph 1, The above ultrafiltration membrane is an ultrafiltration membrane for removing viruses and bacteria, characterized in that it has an average pore size of 0.01-1 μm.

8. In paragraph 1, The above ultrafiltration membrane is an ultrafiltration membrane for removing viruses and bacteria, characterized in that it has a thickness of 50-200 μm.

9. In paragraph 1, The above ultrafiltration membrane is an ultrafiltration membrane for removing viruses and bacteria, characterized in that its cross-sectional structure is sponge-shaped. 10.(A) Step of manufacturing a porous polymer support membrane; (B) a step of coating the porous polymer support membrane by placing it in a positively charged substance solution and immersing it in an oven at 50 to 60°C for 1 to 4 hours; and (C) A method for manufacturing an ultrafiltration membrane for removing viruses and bacteria, comprising: a step of washing the polymer support membrane coated with a positively charged material obtained in step (B) above, and then immersing the polymer support membrane in a crosslinking agent aqueous solution at 15 to 30°C for 5 minutes to 1 hour to crosslink; 11. In paragraph 10, A method for manufacturing an ultrafiltration membrane for removing viruses and bacteria, characterized in that it further comprises a step of heat treatment at 40 to 120°C after the above step (C).

12. In paragraph 10, A method for manufacturing an ultrafiltration membrane for removing viruses and bacteria, characterized in that the crosslinking agent is at least one selected from the group consisting of glutaraldehyde, formaldehyde, and mixtures thereof.

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