Reverse osmosis membrane with antibacterial function as well as preparation method and application of reverse osmosis membrane

Abstract

The invention relates to a reverse osmosis membrane with an antibacterial function and a preparation method and application thereof, the preparation method comprises the following steps: (1) constructing a polyaromatic amide separation layer on the surface of a base membrane through an interfacial polymerization reaction to obtain a nascent state membrane; (2) reacting acyl chloride groups remained on the surface of the nascent state membrane obtained in the step (1) with fatty primary amine to obtain a reverse osmosis membrane with a tertiary aminated surface; and (3) reacting the reverse osmosis membrane subjected to surface tertiary amination obtained in the step (2) with a quaternization reagent to obtain the zwitterionic reverse osmosis membrane. The reverse osmosis membrane provided by the invention has excellent antibacterial function and permeability, and is an excellent material for household reverse osmosis water purifiers.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a reverse osmosis membrane with antibacterial function and a preparation method and application thereof. Background Art

[0002] With the rapid development of society, people pay more and more attention to the safety of drinking water. In view of the fact that reverse osmosis membrane can effectively remove harmful substances such as colloids, bacteria, viruses, pesticides, endocrine disruptors, etc. in water bodies, the water quality of the produced water is much higher than the national drinking water standard, so various household reverse osmosis water purifiers have appeared on the market. Although the existing regulations clearly require that the free residual chlorine in the factory tap water should not be less than 0.3mg / L after 30 minutes of contact, and should not be less than 0.05mg / L at the end of the pipe network, so as to effectively ensure that there will be no bacteria breeding in the tap water body. However, it will be found during use that the household reverse osmosis water purifier is in a shutdown state most of the time. At this time, the free residual chlorine in the water body is quickly consumed, and the surface of the reverse osmosis membrane will also cause the water production to decrease due to bacterial growth, and the water quality of the produced water will deteriorate, so it has to be replaced in advance. Therefore, it is of great significance to prepare a household reverse osmosis membrane with antibacterial function.

[0003] At present, there are some methods for preparing antibacterial reverse osmosis membranes in existing research, such as introducing antibacterial materials in the polyamide separation layer or on the surface of the reverse osmosis membrane to achieve the purpose of antibacterial. According to the antibacterial mechanism, its preparation methods are mainly divided into two types: one is to use a release-type antibacterial material, such as CN107694357A discloses a method for preparing a modified pollution-resistant hybrid reverse osmosis membrane, in which inorganic nanoparticles are dispersed in an organic phase solution and a hybrid polyamide reverse osmosis membrane is formed through interfacial polymerization. In practical applications, the antibacterial nanomaterials in the hybrid polyamide reverse osmosis membrane will be continuously released into the tap water to kill bacteria, but the release of the antibacterial nanomaterial is uncontrollable, and the continuous release during the entire use process leads to a short service life. At the same time, the inorganic nanomaterials may also penetrate into the produced water to cause secondary pollution, endangering human health. The other is to use attached antibacterial materials. For example, CN108057348A discloses a hydrophilic bactericidal and anti-pollution reverse osmosis membrane and its preparation method. A high molecular polymer with bactericidal function is grafted on the surface of the reverse osmosis membrane, and its quaternary ammonium group is used to inactivate cells to achieve the purpose of inhibiting bacterial growth. However, the dead bacteria will adhere to the reverse osmosis membrane, which will still reduce the osmotic flux of the reverse osmosis membrane. In addition, the dead bacteria also provide nutrients and attachment points for the growth of new bacteria to a certain extent. Therefore, the actual antibacterial effect is not ideal.

[0004] Therefore, providing a reverse osmosis membrane with good antibacterial effect is a technical problem that needs to be solved in the current field. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a reverse osmosis membrane with antibacterial function and a preparation method and use thereof. Compared with the prior art, the reverse osmosis membrane provided by the present invention has excellent antibacterial function and permeability, and is an excellent material for household reverse osmosis water purifiers.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a reverse osmosis membrane having an antibacterial function, the preparation method comprising the following steps:

[0008] (1) constructing a polyaromatic amide separation layer on the surface of the base film through an interfacial polymerization reaction to obtain a primary eco-membrane;

[0009] (2) using the acyl chloride groups remaining on the surface of the primary eco-membrane obtained in step (1) to react with a fatty primary amine to obtain a reverse osmosis membrane with a tertiary amine surface;

[0010] (3) reacting the reverse osmosis membrane with tertiary amine on the surface obtained in step (2) with a quaternary ammonium agent to obtain a zwitterionized reverse osmosis membrane.

[0011] In the preparation method provided by the present invention, the acyl chloride groups remaining on the surface of the primary eco-membrane are subjected to an amidation reaction with a fatty primary amine to obtain a tertiary amine group, and further react with a quaternary ammonium agent, thereby successfully grafting a zwitterionic material containing a quaternary ammonium group on the surface of the primary eco-membrane. On the one hand, since the zwitterionic material does not enter the polyaromatic amide separation layer, the interception performance of the reverse osmosis membrane will not be sacrificed; on the other hand, since the zwitterionic material has high hydrophilicity, the permeation flux of the reverse osmosis membrane can be further improved. The reverse osmosis membrane provided by the present invention is used for a water purifier. When the water purifier is in a shutdown state, the zwitterionic material grafted on the membrane surface can form a relatively stable hydration layer, thereby preventing bacteria from attaching to the membrane surface. Even if a small amount of bacteria approaches the membrane surface, the quaternary ammonium group cation can be used to kill it, effectively realizing the antibacterial effect of the shutdown state; when the water purifier is in a startup state, the tap water contains a trace amount of free chlorine, and its preferential degradation effect on fatty amides can be used to make the dead bacteria leave together with the zwitterionic material, and the permeability of the reverse osmosis membrane is restored. In addition, the preparation method provided by the present invention is simple to operate and is conducive to popularization and application in the production process of household reverse osmosis membranes.

[0012] Preferably, the base membrane in step (1) comprises any one of polysulfone, polyethersulfone or sulfonated polyethersulfone, or a combination of at least two thereof.

[0013] In the present invention, the base membrane can be any base membrane material commonly used in the art for reverse osmosis membranes, for example, a polysulfone microporous membrane, and the pore size is not particularly limited, for example, it can be 10-80nm, specifically, for example, it can be 10nm, 20nm, 40nm, 50nm, 60nm or 80nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] Preferably, the aqueous reaction phase used in the interfacial polymerization reaction in step (1) comprises an aqueous solution of a water-soluble monomer.

[0015] Preferably, the water-soluble monomer includes any one of m-phenylenediamine, p-phenylenediamine or 3,4-diaminotoluene, or a combination of at least two thereof.

[0016] Preferably, the mass percentage of the water-soluble monomer in the reaction aqueous phase is 2.0-4.0%, for example, 2%, 2.5%, 3%, 3.5% or 4%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] Preferably, the reaction oil phase used in the interfacial polymerization reaction in step (1) comprises an oil-soluble monomer and an organic solvent.

[0018] Preferably, the oil-soluble monomer includes any one of trimesoyl chloride, isophthaloyl chloride or terephthaloyl chloride, or a combination of at least two thereof.

[0019] Preferably, the organic solvent comprises an isomeric alkane.

[0020] In the present invention, the isoparaffin may be, for example, any one of Isopar E, Isopar G or Isopar H produced by ExxonMobil, or a combination of at least two thereof.

[0021] Preferably, the mass percentage of the oil-soluble monomer in the reaction oil phase is 0.1-0.3%, for example, it can be 0.1%, 0.15%, 0.2%, 0.25% or 0.3%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the process of the interfacial polymerization reaction in step (1) includes: coating a reaction water phase on the surface of the base film, and then removing excess reaction water phase; then coating a reaction oil phase on the surface of the base film coated with the reaction water phase to perform an interfacial polymerization reaction, and then performing heat treatment to obtain a primary ecological film.

[0023] Preferably, the time of the interfacial polymerization reaction is 0.5-2.5 min, for example, it can be 0.6 min, 0.8 min, 1 min, 1.2 min, 1.4 min, 1.6 min, 1.8 min, 2 min, 2.2 min, 2.4 min or 2.5 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the heat treatment temperature is 80-110°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C or 110°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the heat treatment time is 3-6 min, for example, 3 min, 3.5 min, 4 min, 4.5 min, 5 min, 5.5 min or 6 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the reaction process of step (2) comprises: immersing the nascent membrane in a fatty primary amine solution.

[0027] Preferably, the primary fatty amine includes any one of 3-dimethylaminopropylamine, 4-dimethylaminobutylamine or N,N-dimethylethylenediamine, or a combination of at least two thereof.

[0028] Preferably, the solvent of the primary fatty amine solution includes water.

[0029] Preferably, the mass concentration of the fatty primary amine solution is 0.5-5.0%, for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] In the present invention, by preferably controlling the mass concentration of the fatty primary amine solution within a specific range, a sufficient number of tertiary amine groups can be introduced onto the surface of the primary eco-film, thus laying a foundation for subsequent quaternization.

[0031] Preferably, the reaction time of step (2) is 5-10 min, for example, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] In the present invention, by preferably controlling the reaction time of step (2) within a specific range, a sufficient number of tertiary amine groups can be introduced without sacrificing production efficiency, thereby laying a foundation for subsequent quaternization.

[0033] Preferably, the reaction process of step (3) comprises: immersing the reverse osmosis membrane with tertiary amine on the surface in a quaternary ammonium agent solution.

[0034] Preferably, the quaternizing agent comprises sodium 3-chloro-2-hydroxypropyl sulfonate.

[0035] Preferably, the solvent of the quaternizing agent solution comprises water.

[0036] Preferably, the mass concentration of the quaternary ammonium agent solution is 1.0-6.0%, for example, it can be 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 5.8% or 6%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In the present invention, by preferably controlling the mass concentration of the quaternary ammonium agent solution within a specific range, a sufficient amount of zwitterions can be introduced to ensure that the reverse osmosis membrane has an excellent antibacterial effect.

[0038] Preferably, the reaction time of step (3) is 5-20 min, for example, it can be 5 min, 6 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min or 20 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] In the present invention, the reaction time of step (3) is preferably controlled within a specific range, so that a sufficient amount of zwitterions can be introduced without sacrificing production efficiency, thereby ensuring that the reverse osmosis membrane has an excellent antibacterial effect.

[0040] As a preferred technical solution of the first aspect of the present invention, the preparation method comprises the following steps:

[0041] (1) constructing a polyaromatic amide separation layer on the surface of a base film by interfacial polymerization to obtain a primary ecological film, wherein the reaction water phase used in the interfacial polymerization reaction includes an aqueous solution of a water-soluble monomer, wherein the water-soluble monomer includes any one of m-phenylenediamine, p-phenylenediamine or 3,4-diaminotoluene or a combination of at least two thereof, and the mass percentage of the water-soluble monomer in the reaction water phase is 2.0-4.0%. The reaction oil phase used in the interfacial polymerization reaction includes an oil-soluble monomer and an organic solvent, wherein the oil-soluble monomer includes any one of trimesoyl chloride, isophthaloyl chloride or terephthaloyl chloride or a combination of at least two thereof, and the organic solvent includes isoparaffin, and the mass percentage of the oil-soluble monomer in the reaction oil phase is 0.1-0.3%. The process of the interfacial polymerization reaction includes: coating the reaction water phase on the surface of the base film, and then removing excess reaction water phase; then coating the reaction oil phase on the surface of the base film coated with the reaction water phase to perform interfacial polymerization for 0.5-2.5 min, and then heat treating at 80-110° C. for 3-6 min;

[0042] (2) using the acyl chloride groups remaining on the surface of the nascent membrane obtained in step (1) to react with a fatty primary amine to obtain a reverse osmosis membrane with tertiary amine on the surface, the reaction process comprising: immersing the nascent membrane in a fatty primary amine solution for reaction for 5-10 minutes, the fatty primary amine comprising any one of 3-dimethylaminopropylamine, 4-dimethylaminobutylamine or N,N-dimethylethylenediamine or a combination of at least two thereof, the mass concentration of the fatty primary amine solution being 0.5-5.0%;

[0043] (3) reacting the surface tertiary aminated reverse osmosis membrane obtained in step (2) with a quaternary ammonium reagent to obtain a zwitterionized reverse osmosis membrane, wherein the reaction process comprises: immersing the surface tertiary ammonium reagent in a quaternary ammonium reagent solution for a reaction of 5-20 minutes, wherein the quaternary ammonium reagent comprises sodium 3-chloro-2-hydroxypropyl sulfonate, and the mass concentration of the quaternary ammonium reagent solution is 1.0-6.0%.

[0044] In a second aspect, the present invention provides a reverse osmosis membrane with antibacterial function, wherein the reverse osmosis membrane with antibacterial function is obtained by the method for preparing the reverse osmosis membrane with antibacterial function according to the first aspect of the present invention.

[0045] The reverse osmosis membrane provided by the present invention has excellent separation performance and antibacterial performance and has broad application prospects.

[0046] In a third aspect, the present invention provides a use of a reverse osmosis membrane having an antibacterial function as described in the second aspect of the present invention, wherein the reverse osmosis membrane is used in a household reverse osmosis water purifier.

[0047] The reverse osmosis membrane provided by the present invention is used in a household reverse osmosis water purifier, and can prevent bacteria from attaching and sterilize in a shutdown state, thereby achieving effective antibacterial effect in the shutdown state; in an on-state, the preferential degradation of its fatty amide by trace free chlorine in tap water is utilized, so that the dead bacteria leave with the zwitterionic material, and the permeability performance of the reverse osmosis membrane is restored, thereby achieving good separation function and antibacterial function.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) In the method for preparing the reverse osmosis membrane provided by the present invention, the zwitterionic material is successfully grafted on the surface of the primary ecological membrane through surface tertiary amination and quaternary ammonium reactions in sequence. On the one hand, the zwitterionic material does not enter the polyaromatic amide separation layer, so the retention performance of the reverse osmosis membrane is not sacrificed; on the other hand, since the zwitterionic material has high hydrophilicity, the permeation flux of the reverse osmosis membrane can be further improved.

[0050] (2) The reverse osmosis membrane provided by the present invention has good separation performance and antibacterial performance, and the preparation method is simple to operate, which is conducive to promotion and application in the production process of household reverse osmosis membranes.

[0051] (3) The reverse osmosis membrane provided by the present invention is used in a household reverse osmosis water purifier. When the water purifier is in shutdown state, the zwitterionic material grafted on the membrane surface can form a relatively stable hydration layer, thereby preventing bacteria from adhering to the membrane surface. Even if a small amount of bacteria approach the membrane surface, they can be killed by the quaternary ammonium group cations, thereby effectively achieving antibacterial effect in the shutdown state; when the water purifier is in the startup state, the tap water contains a trace amount of free chlorine, which can utilize its preferential degradation effect on fatty amides to make the dead bacteria leave together with the zwitterionic material, thereby restoring the permeability of the reverse osmosis membrane, and finally achieving good antibacterial effect and stable operation.

[0052] (4) Specifically, under optimal conditions, the reverse osmosis membrane provided by the present invention has a pure water permeation flux of 52.9-55.9 L / (m 2 h), the sodium chloride retention rate reached more than 98.1%, the flux attenuation rate reached less than 16.8%, and the flux recovery rate reached more than 84.1%. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the antibacterial principle of the reverse osmosis membrane provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] Example 1

[0056] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function, the preparation method comprising the following steps:

[0057] (1) constructing a polyaromatic amide separation layer on the surface of a polysulfone microporous membrane (pore size of 20 nm) by interfacial polymerization to obtain a primary ecological membrane, wherein the reaction water phase used in the interfacial polymerization reaction includes an aqueous solution of m-phenylenediamine with a mass percentage of 2.5%, and the reaction oil phase used in the interfacial polymerization reaction includes trimesoyl chloride and isoparaffin solvent Isopar G (manufacturer ExxonMobil), and the mass percentage of trimesoyl chloride is 0.2%. The process of the interfacial polymerization reaction includes: coating the reaction water phase on the surface of the base membrane, and then removing the excess reaction water phase; then coating the reaction oil phase on the surface of the base membrane coated with the reaction water phase to perform an interfacial polymerization reaction for 1 minute, and then heat treating at 100° C. for 5 minutes;

[0058] (2) using the acyl chloride groups remaining on the surface of the nascent eco-membrane obtained in step (1) to react with 3-dimethylaminopropylamine to obtain a reverse osmosis membrane with tertiary amine on the surface, the reaction process comprising: immersing the nascent eco-membrane in a 3-dimethylaminopropylamine aqueous solution with a mass concentration of 1% for a reaction of 5 minutes;

[0059] (3) reacting the surface tertiary aminated reverse osmosis membrane obtained in step (2) with sodium 3-chloro-2-hydroxypropyl sulfonate to obtain a zwitterionized reverse osmosis membrane, wherein the reaction process comprises: immersing the surface tertiary aminated reverse osmosis membrane in a 1% sodium 3-chloro-2-hydroxypropyl sulfonate aqueous solution for reacting for 5 minutes.

[0060] The antibacterial principle of the reverse osmosis membrane provided in this embodiment is as follows Figure 1 As shown, when the water purifier is in shutdown state, the zwitterionic material grafted on the membrane surface can form a relatively stable hydration layer, thereby preventing bacteria from adhering to the membrane surface. Even if a small amount of bacteria approach the membrane surface, they can be killed by the quaternary ammonium group cations, effectively achieving antibacterial effect in the shutdown state; when the water purifier is in startup state, the tap water contains trace amounts of free chlorine, which can utilize its preferential degradation effect on fatty amides to make the dead bacteria leave together with the zwitterionic material, thereby restoring the permeability of the reverse osmosis membrane and ultimately achieving good antibacterial effect and stable operation.

[0061] Example 2

[0062] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function, the preparation method comprising the following steps:

[0063] (1) constructing a polyaromatic amide separation layer on the surface of a polysulfone microporous membrane (the same as in Example 1) by interfacial polymerization to obtain a primary ecological membrane, wherein the reaction water phase used in the interfacial polymerization reaction comprises an aqueous solution of m-phenylenediamine with a mass percentage of 2%, and the reaction oil phase used in the interfacial polymerization reaction comprises trimesoyl chloride and an isoparaffin solvent Isopar G (the same as in Example 1), wherein the mass percentage of trimesoyl chloride is 0.25%, and the process of the interfacial polymerization reaction comprises: coating the reaction water phase on the surface of the base membrane, and then removing the excess reaction water phase; then coating the reaction oil phase on the surface of the base membrane coated with the reaction water phase to perform an interfacial polymerization reaction for 2.5 minutes, and then heat treating at 110° C. for 3 minutes;

[0064] (2) using the acyl chloride groups remaining on the surface of the nascent eco-membrane obtained in step (1) to react with 3-dimethylaminopropylamine to obtain a reverse osmosis membrane with tertiary amine on the surface, the reaction process comprising: immersing the nascent eco-membrane in a 3-dimethylaminopropylamine aqueous solution with a mass concentration of 1.5% for a reaction of 10 minutes;

[0065] (3) reacting the surface tertiary aminated reverse osmosis membrane obtained in step (2) with sodium 3-chloro-2-hydroxypropyl sulfonate to obtain a zwitterionized reverse osmosis membrane, wherein the reaction process comprises: immersing the surface tertiary aminated reverse osmosis membrane in a 1% sodium 3-chloro-2-hydroxypropyl sulfonate aqueous solution for reacting for 5 minutes.

[0066] Example 3

[0067] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function, the preparation method comprising the following steps:

[0068] (1) constructing a polyaromatic amide separation layer on the surface of a polysulfone microporous membrane (the same as in Example 1) by interfacial polymerization to obtain a primary ecological membrane, wherein the reaction water phase used in the interfacial polymerization reaction comprises an aqueous solution of m-phenylenediamine with a mass percentage of 2%, and the reaction oil phase used in the interfacial polymerization reaction comprises trimesoyl chloride and an isoparaffin solvent Isopar G (the same as in Example 1), wherein the mass percentage of trimesoyl chloride is 0.3%, and the process of the interfacial polymerization reaction comprises: coating the reaction water phase on the surface of the base membrane, and then removing the excess reaction water phase; then coating the reaction oil phase on the surface of the base membrane coated with the reaction water phase to perform an interfacial polymerization reaction for 2 minutes, and then heat treating at 80° C. for 6 minutes;

[0069] (2) using the acyl chloride groups remaining on the surface of the nascent eco-membrane obtained in step (1) to react with 4-dimethylaminobutylamine to obtain a reverse osmosis membrane with tertiary amine on the surface, the reaction process comprising: immersing the nascent eco-membrane in a 4-dimethylaminobutylamine aqueous solution with a mass concentration of 1.5% for a reaction of 10 minutes;

[0070] (3) reacting the surface tertiary aminated reverse osmosis membrane obtained in step (2) with sodium 3-chloro-2-hydroxypropyl sulfonate to obtain a zwitterionized reverse osmosis membrane, wherein the reaction process comprises: immersing the surface tertiary aminated reverse osmosis membrane in a 3-chloro-2-hydroxypropyl sulfonate aqueous solution having a mass concentration of 2% and reacting for 10 minutes.

[0071] Example 4

[0072] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function. The difference between the preparation method and the embodiment 1 is that the mass concentration of the 3-chloro-2-hydroxypropyl sodium sulfonate aqueous solution is 2%.

[0073] Example 5

[0074] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function. The difference between the preparation method and Example 4 is that the 3-dimethylaminopropylamine aqueous solution with a mass concentration of 1% is replaced by a 4-dimethylaminobutylamine aqueous solution with a mass concentration of 2%.

[0075] Example 6

[0076] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function. The difference between the preparation method and Example 5 is that the reaction time in step (2) is 10 minutes, and the reaction time in step (3) is 10 minutes.

[0077] Example 7

[0078] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function. The difference between the preparation method and the embodiment 1 is that the mass concentration of the 3-dimethylaminopropylamine aqueous solution is 0.1%.

[0079] Example 8

[0080] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function. The difference between the preparation method and embodiment 1 is that the reaction time in step (2) is 3 minutes.

[0081] Example 9

[0082] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function. The difference between the preparation method and the embodiment 1 is that the mass concentration of the 3-chloro-2-hydroxypropyl sodium sulfonate aqueous solution is 0.5%.

[0083] Example 10

[0084] This embodiment provides a method for preparing a reverse osmosis membrane with antibacterial function. The difference between the preparation method and embodiment 1 is that the reaction time in step (3) is 3 minutes.

[0085] Comparative Example 1

[0086] This comparative example provides a method for preparing a reverse osmosis membrane. The only difference compared with Example 1 is that only step (1) is performed to obtain a nascent membrane, and the nascent membrane is immersed in pure water and taken out after 10 minutes to obtain a reverse osmosis membrane.

[0087] Performance Testing:

[0088] (1) Permeation flux test:

[0089] Permeation flux of reverse osmosis membrane (J, L / (m 2 h)) was evaluated by cross-flow osmosis, with pure water as feed liquid, and the operating pressure was controlled at 0.41 MPa, the temperature was 25°C, the membrane surface flow rate was 0.45 m / s, and the effective membrane area (S, m) per unit time (t) was tested after pre-pressing for 30 min. 2 The volume of water (V, L) is calculated according to the following formula:

[0090] Where J represents the permeation flux, L / (m 2 ·h); S represents the effective membrane area, m 2 ; t represents time, h; V represents the volume of water, L.

[0091] (2) Sodium chloride retention rate test:

[0092] The sodium chloride rejection rate (R, %) of the reverse osmosis membrane was evaluated by cross-flow osmosis. Specifically, 250 mg / L sodium chloride aqueous solution was used as the feed solution, and the operating pressure was controlled to be 0.41 MPa, the temperature was 25 °C, the membrane surface flow rate was 0.45 m / s, and the feed solution concentration (C feed ) and the permeate concentration (C permeate ), which is calculated according to the following formula:

[0093] Where R represents the sodium chloride retention rate, %; C permeate Indicates the concentration of permeate; C feed Indicates the feed solution concentration.

[0094] (3) Evaluation of antibacterial performance:

[0095] The antibacterial performance of the reverse osmosis membrane was evaluated by measuring the permeate flux attenuation rate (D, %) after contact with the bacteria-containing solution and the permeate flux recovery rate (R, %) after immersion in sodium hypochlorite. The highly active bacterial stock solution obtained by continuous culture was diluted with culture medium and phosphate buffer solution in turn to obtain a total bacterial count of 10 7 -10 8 CFU / mL of bacterial suspension.

[0096] First, the initial permeation flux (J) of the reverse osmosis membrane was tested. 0 ,L / (m 2 ·h)); then, the reverse osmosis membrane was immersed in the bacterial suspension and taken out after 24h to test the permeation flux (J 1 ,L / (m 2 ·h)); then, the reverse osmosis membrane was immersed in an aqueous solution of sodium hypochlorite with an effective chlorine concentration of 0.05 mg / L, and the permeation flux was tested after 1 min (J 2 ,L / (m 2 h)); the flux attenuation rate D and recovery rate R of the reverse osmosis membrane are calculated according to the following formulas respectively.

[0097] Where, D represents the permeation flux attenuation rate, %; J 1 Indicates the permeate flux after bacterial contamination, L / (m 2 ·h); J 0 represents the initial permeation flux, L / (m 2 h);

[0098] Where, R represents the permeation flux recovery rate, %; J 1 Indicates the permeate flux after bacterial contamination, L / (m 2 ·h); J 0 represents the initial permeation flux, L / (m 2 ·h); J 2 Represents the permeate flux after recovery, L / (m 2 h).

[0099] The test data of the reverse osmosis membranes obtained in the above examples and comparative examples are shown in Table 1.

[0100] Table 1

[0101]

[0102] From the data in Table 1, we can see the following points:

[0103] (1) From the data of Examples 1-6, it can be seen that under optimal conditions, the pure water permeation flux of the reverse osmosis membrane provided by the present invention reaches 52.9-55.9 L / (m 2h), the sodium chloride retention rate reached more than 98.1%, the flux attenuation rate reached less than 16.8%, and the flux recovery rate reached more than 84.1%.

[0104] (2) It can be seen from the data of Examples 1 and 7-10 that the present invention can further enhance the effect of grafting zwitterionic materials onto the membrane surface by preferably controlling the mass concentration of the fatty primary amine aqueous solution and the reaction time of step (2), and by preferably controlling the mass concentration of the quaternizing agent and the reaction time of step (3), thereby further enhancing the separation performance and antibacterial performance.

[0105] (3) From the data of Example 1, Examples 4-6 and Comparative Example 1, it can be seen that the reverse osmosis membrane provided by the present invention can increase the hydrophilicity of the reverse osmosis membrane by introducing zwitterionic materials on the membrane surface, thereby effectively improving the pure water permeation flux; at the same time, after the zwitterionic materials are introduced in the present invention, the retention rate of sodium chloride is basically within the range of 98.1-98.3%, without obvious changes, indicating that the surface grafting does not sacrifice the retention rate of sodium chloride;

[0106] At the same time, after the reverse osmosis membrane of the above embodiment was in contact with the bacteria-containing solution for 24 hours, the attenuation rate of the permeation flux was significantly lower than that of Comparative Example 1, indicating that the reverse osmosis membrane after the introduction of the zwitterionic material can inhibit the reproduction of bacteria in the solution on the membrane surface; and after being soaked in the sodium hypochlorite solution, the flux recovery rate was much higher than that of Comparative Example 1, indicating that even if part of it remained on the membrane surface, it could be recovered by the sodium hypochlorite in the aqueous solution.

[0107] In summary, the reverse osmosis membrane provided by the present invention has excellent antibacterial function and permeability, and is an excellent material for household reverse osmosis water purifiers.

[0108] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a reverse osmosis membrane with antibacterial function, characterized in that: The preparation method comprises the following steps: (1) constructing a polyaromatic amide separation layer on the surface of the base film through an interfacial polymerization reaction to obtain a primary eco-membrane; (2) using the acyl chloride groups remaining on the surface of the primary eco-membrane obtained in step (1) to react with a fatty primary amine to obtain a reverse osmosis membrane with a tertiary amine surface; (3) reacting the reverse osmosis membrane with tertiary amine on the surface obtained in step (2) with a quaternary ammonium agent to obtain a zwitterionized reverse osmosis membrane.

2. The preparation method according to claim 1, characterized in that: The components of the base membrane in step (1) include any one of polysulfone, polyethersulfone or sulfonated polyethersulfone, or a combination of at least two thereof.

3. The preparation method according to claim 1 or 2, characterized in that: The aqueous reaction phase used in the interfacial polymerization reaction in step (1) comprises an aqueous solution of a water-soluble monomer; Preferably, the water-soluble monomer includes any one of m-phenylenediamine, p-phenylenediamine or 3,4-diaminotoluene or a combination of at least two thereof; Preferably, the mass percentage of the water-soluble monomer in the reaction water phase is 2.0-4.0%.

4. The preparation method according to any one of claims 1 to 3, characterized in that The reaction oil phase used in the interfacial polymerization reaction in step (1) comprises an oil-soluble monomer and an organic solvent; Preferably, the oil-soluble monomer includes any one of trimesoyl chloride, isophthaloyl chloride or terephthaloyl chloride, or a combination of at least two thereof; Preferably, the organic solvent comprises isomeric alkanes; Preferably, the mass percentage of the oil-soluble monomer in the reaction oil phase is 0.1-0.3%.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The process of the interfacial polymerization reaction in step (1) comprises: coating a reaction water phase on the surface of the base film, and then removing excess reaction water phase; then coating a reaction oil phase on the surface of the base film coated with the reaction water phase to perform an interfacial polymerization reaction, and then performing a heat treatment to obtain a primary ecological film; Preferably, the interfacial polymerization reaction time is 0.5-2.5 min; Preferably, the temperature of the heat treatment is 80-110°C; Preferably, the heat treatment time is 3-6 minutes.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The reaction process of step (2) comprises: immersing the nascent membrane in a fatty primary amine solution; Preferably, the fatty primary amine includes any one of 3-dimethylaminopropylamine, 4-dimethylaminobutylamine or N,N-dimethylethylenediamine or a combination of at least two thereof; Preferably, the solvent of the fatty primary amine solution includes water; Preferably, the mass concentration of the fatty primary amine solution is 0.5-5.0%; Preferably, the reaction time in step (2) is 5-10 min.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The reaction process of step (3) comprises: immersing the reverse osmosis membrane with tertiary amine on the surface in a quaternary ammonium reagent solution; Preferably, the quaternizing agent comprises sodium 3-chloro-2-hydroxypropyl sulfonate; Preferably, the solvent of the quaternizing agent solution comprises water; Preferably, the mass concentration of the quaternary ammonium agent solution is 1.0-6.0%; Preferably, the reaction time in step (3) is 5-20 min.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) constructing a polyaromatic amide separation layer on the surface of a base film by interfacial polymerization to obtain a primary ecological film, wherein the reaction water phase used in the interfacial polymerization reaction includes an aqueous solution of a water-soluble monomer, wherein the water-soluble monomer includes any one of m-phenylenediamine, p-phenylenediamine or 3,4-diaminotoluene or a combination of at least two thereof, and the mass percentage of the water-soluble monomer in the reaction water phase is 2.0-4.0%. The reaction oil phase used in the interfacial polymerization reaction includes an oil-soluble monomer and an organic solvent, wherein the oil-soluble monomer includes any one of trimesoyl chloride, isophthaloyl chloride or terephthaloyl chloride or a combination of at least two thereof, and the organic solvent includes isoparaffin, and the mass percentage of the oil-soluble monomer in the reaction oil phase is 0.1-0.3%. The process of the interfacial polymerization reaction includes: coating the reaction water phase on the surface of the base film, and then removing excess reaction water phase; then coating the reaction oil phase on the surface of the base film coated with the reaction water phase to perform interfacial polymerization for 0.5-2.5 min, and then heat treating at 80-110° C. for 3-6 min; (2) using the acyl chloride groups remaining on the surface of the nascent membrane obtained in step (1) to react with a fatty primary amine to obtain a reverse osmosis membrane with tertiary amine on the surface, the reaction process comprising: immersing the nascent membrane in a fatty primary amine solution for reaction for 5-10 minutes, the fatty primary amine comprising any one of 3-dimethylaminopropylamine, 4-dimethylaminobutylamine or N,N-dimethylethylenediamine or a combination of at least two thereof, the mass concentration of the fatty primary amine solution being 0.5-5.0%; (3) reacting the surface tertiary aminated reverse osmosis membrane obtained in step (2) with a quaternary ammonium reagent to obtain a zwitterionized reverse osmosis membrane, wherein the reaction process comprises: immersing the surface tertiary ammonium reagent in a quaternary ammonium reagent solution for a reaction of 5-20 minutes, wherein the quaternary ammonium reagent comprises sodium 3-chloro-2-hydroxypropyl sulfonate, and the mass concentration of the quaternary ammonium reagent solution is 1.0-6.0%.

9. A reverse osmosis membrane with antibacterial function, characterized in that: The reverse osmosis membrane with antibacterial function is obtained by the method for preparing the reverse osmosis membrane with antibacterial function according to any one of claims 1 to 8.

10. Use of the reverse osmosis membrane with antibacterial function as claimed in claim 9, characterized in that: The reverse osmosis membrane is used for a household reverse osmosis water purifier.

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