Bacteriostatic reverse osmosis membrane and preparation method and application thereof

Abstract

The application discloses a bacteriostatic reverse osmosis membrane and a preparation method and application thereof. The bacteriostatic reverse osmosis membrane disclosed by the application comprises a non-woven fabric base layer, a porous support layer and a separation layer. The surface of the nascent polyamide membrane is grafted and modified by tazobactam acid, so that the prepared reverse osmosis membrane has excellent bacteriostatic performance while maintaining the original separation performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment, and relates to a bacteriostatic reverse osmosis membrane and a preparation method and application thereof. BACKGROUND

[0002] Reverse osmosis technology has developed rapidly in China since the 1990s and is widely used in various industries, especially in the fields of seawater desalination, industrial wastewater treatment and household purifiers. Reverse osmosis membranes can effectively intercept dissolved salts and organic matter with a molecular weight greater than 100, while allowing water molecules to pass through, and have the advantages of low energy consumption and simple process. However, in actual use, in addition to normal performance degradation, reverse osmosis membranes also face varying degrees of pollution, including bacterial pollution. Therefore, reverse osmosis membranes need stronger bacteriostatic performance.

[0003] CN114917776B realizes double antibacterial effect by coating a protective layer containing carboxymethyl chitosan quaternary ammonium salt / titanium dioxide complex on the surface of the reverse osmosis membrane, using the cationic antibacterial properties of carboxymethyl chitosan quaternary ammonium salt and the photocatalytic antibacterial properties of titanium dioxide. It is used in water treatment fields that require high-efficiency antibacterial performance, such as drinking water production and wastewater treatment, which can effectively inhibit the growth and reproduction of microorganisms and ensure water quality safety. CN115228291B introduces a blend of stilbene compounds containing sulfonic acid and amino structures and aromatic quaternary ammonium salt on the surface of the functional layer of the reverse osmosis membrane. These compounds have strong antibacterial properties and can damage bacterial cell walls or membranes, leading to bacterial death. It is widely used in water treatment fields such as wastewater reuse and industrial water supply, which can effectively inhibit the adhesion and growth of microorganisms while maintaining high desalination rate and water flux, prolonging the service life of the membrane. CN112426884A obtains antibacterial performance through specific post-processing processes such as grafting antibacterial groups and coating antibacterial layers, which is used in water treatment scenarios that require excellent chlorine resistance, excellent anti-pollution performance and high antibacterial performance, such as seawater desalination and boiler water supply. CN107303470B realizes antibacterial effect by coating a high-molecular cross-linked coating containing attapulgite / silicon dioxide-nano silver composite inorganic powder on the reverse osmosis membrane. Nano silver has broad-spectrum antibacterial properties and can damage the DNA structure of bacteria, inhibiting their growth and reproduction. It is widely used in water treatment fields that require high-efficiency antibacterial performance, such as drinking water production and pharmaceutical water treatment.

[0004] Although the existing technology can improve the bacteriostatic performance of the reverse osmosis membrane to a certain extent, there are still problems of limited antibacterial ability. Therefore, it is urgent to develop a reverse osmosis membrane with better bacteriostatic effect. SUMMARY

[0005] The purpose of the present application is to provide a bacteriostatic reverse osmosis membrane to solve the above problems in the prior art.

[0006] In a first aspect, the present application provides a bacteriostatic reverse osmosis membrane, comprising a non-woven fabric base layer, a porous support layer and a separation layer, wherein:

[0007] the porous support layer is a composite ultrafiltration membrane formed on the non-woven fabric base layer by phase inversion of polysulfone; and

[0008] the separation layer is a polyamide membrane obtained by interfacial polymerization of an aromatic polyamine compound and an aromatic acid chloride compound on the porous support layer, and then grafting modification of tazobactam acid.

[0009] In some embodiments, in the above-mentioned bacteriostatic reverse osmosis membrane, the non-woven fabric base layer is selected from one of polyester non-woven fabric, polypropylene non-woven fabric, polyethylene non-woven fabric;

[0010] the aromatic polyamine compound is selected from one or more of m-phenylenediamine, m-phenylenediamine, p-phenylenediamine; and / or

[0011] the aromatic acid chloride compound is selected from one or more of m-phenylenediamine, m-phenylenediamine, p-phenylenediamine.

[0012] In some embodiments, in any of the above-mentioned bacteriostatic reverse osmosis membranes, the thickness of the non-woven fabric base layer is 90-100 μm;

[0013] the pore size of the porous support layer is between 5-100 nm, and the thickness is 30-60 μm; and / or

[0014] the thickness of the separation layer is 100-300 nm.

[0015] In some embodiments, in any of the above-mentioned bacteriostatic reverse osmosis membranes, the bacteriostatic rate of the bacteriostatic reverse osmosis membrane is more than 10%, for example, more than 11%, more than 12%, more than 13%, more than 14%, more than 15%, more than 16%, more than 17%.

[0016] In a second aspect, the present application provides a preparation method of any of the above-mentioned bacteriostatic reverse osmosis membranes, comprising the following steps:

[0017] S1, dissolving polysulfone in N,N-dimethylformamide to obtain a 15-20 wt% (for example, 15, 16, 17, 18, 19, 20 wt%, or any value or range between these values) polysulfone casting solution, uniformly coating and scraping it on the non-woven fabric base layer, and then phase-inverting into a composite ultrafiltration membrane in water to form a porous support layer on the non-woven fabric base layer;

[0018] S2, contacting the membrane treated in step S1 with an aqueous solution of an aromatic polyamine compound, then discarding the excess aqueous solution on the surface and air-drying;

[0019] S3, contacting the membrane treated in step S2 with an organic solution of aromatic acid chloride compound, allowing the aromatic polyamine compound and the aromatic acid chloride compound to undergo interfacial polymerization reaction on the porous support layer, discarding the excess organic solution, and removing the residual organic solvent on the surface to form a polyamide reverse osmosis membrane;

[0020] S4, immersing the polyamide reverse osmosis membrane in an aqueous solution of aztreonam acid for reaction, taking out the membrane and washing with water to obtain the bacteriostatic reverse osmosis membrane.

[0021] In some embodiments, in the above preparation method, in step S2, the concentration of the aqueous solution of the aromatic polyamine compound is 1.0-5.0wt%, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0wt%, or any value or range between these values; and / or

[0022] The contacting time is 0.5-2min, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0min, or any value or range between these values.

[0023] In some embodiments, in any of the above preparation methods, in step S3, the concentration of the organic solution of the aromatic acid chloride compound is 0.1-2.0wt%, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0wt%, or any value or range between these values;

[0024] The solvent of the organic solution of the aromatic acid chloride compound is selected from one or more of hexane, heptane, decane, cyclohexane, ethylcyclohexane, for example, hexane, heptane, decane, cyclohexane, ethylcyclohexane can be used in any proportion; and / or

[0025] The contact time is 0.5-2.0 min, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 min, or any value or range between these values.

[0026] In some embodiments, in any one of the above-mentioned preparation methods, the non-woven fabric base layer is selected from one of a polyester non-woven fabric, a polypropylene non-woven fabric, and a polyethylene non-woven fabric.

[0027] The aromatic polyamine compound is selected from one or more of m-phenylenediamine, m-phenylenediamine, and p-phenylenediamine; and / or

[0028] The aromatic acid chloride compound is selected from one or more of m-phenyltricarboxylic acid chloride, p-phenyldicarboxylic acid chloride, and m-phenyldicarboxylic acid chloride.

[0029] In some embodiments, in any one of the above-mentioned preparation methods, in step S4, the concentration of the aqueous solution of tazobactam acid is 0.1-0.3 wt%, for example, 0.1, 0.15, 0.2, 0.25, 0.3 wt%, or any value and range between these values; and / or

[0030] The reaction time is 30-60 min, for example, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 min, or any value or range between these values, and the reaction temperature is room temperature, for example, 15-25℃, and further for example, 25℃.

[0031] In a third aspect, the present application provides the use of any one of the above-mentioned bacteriostatic reverse osmosis membranes in the preparation of a water treatment component and / or in a water treatment method.

[0032] Tazobactam acid has strong enzyme inhibition activity, wide enzyme inhibition spectrum, and good stability, and has excellent antibacterial performance. In the present application, the acyl chloride groups remaining on the surface of the polyamide reverse osmosis membrane are subjected to polycondensation reaction with tazobactam acid, tazobactam acid is grafted to the membrane surface, and the membrane is modified to have bacteriostatic effect.

[0033] It should be noted that the "contacting" in the present application can be immersing the membrane in the corresponding solution and then taking it out, or pouring or coating the corresponding solution on the surface of the membrane, or a combination of the two, and other common "contacting" methods in the art, the key is to coat the corresponding reactant on the surface of the membrane to prepare for subsequent grafting. The present application preferably interfaces with the contact, so that the interfacial polymerization reaction preferably occurs at the interface. Such "contacting" methods are understood by those skilled in the art and should be within the scope of the present application.

[0034] The present application has the following advantages:

[0035] The present application has the following advantages:

[0036] The present application has the following advantages: DETAILED DESCRIPTION

[0037] The present application will be further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present application and not to limit the scope of the present application. Unless otherwise specified, the technical means used in the examples are conventional operations in the art, or according to the experimental methods suggested by the manufacturers of the kits and instrument equipment. The reagents and biological materials used in the examples, unless otherwise specified, can be obtained commercially.

[0038] Evaluation of desalination rate and permeation flux

[0039] Desalination rate and permeation flux are two important parameters for evaluating the separation performance of reverse osmosis membranes. The present application evaluates the separation performance of reverse osmosis membranes according to GB / T32373-2015 "Test method for reverse osmosis membranes".

[0040] Desalination rate (R) is defined as the difference between the salt concentration (C f ) of the feed liquid and the salt concentration (C p ) in the permeate under certain operating conditions, divided by the salt concentration (C f ) of the feed liquid, and the calculation formula is shown in formula (1).

[0041]

[0042] Permeation flux (F) is defined as the volume of water per unit membrane area per unit time under certain operating conditions, and its unit is L / (m 2 ·h).

[0043] The operation conditions for measuring the performance of the reverse osmosis membrane in the present application are as follows: the feed liquid is a 2000 ppm sodium chloride aqueous solution, the pH of the solution is 7.0±0.5, the operation pressure is 1.55 MPa, and the temperature of the feed liquid is 25℃.

[0044] The antibacterial test method is as follows:

[0045] Sample preparation: cut the membrane sample to be tested into small pieces with a length and width of 25±5 mm.

[0046] Bacterial solution preparation: inoculate Escherichia coli into nutrient broth and culture at a suitable temperature (37±1℃) until the desired bacterial concentration of 10^6 CFU / mL (colony forming units per milliliter) is reached.

[0047] Sample inoculation: place the prepared sample into a flask containing the bacterial solution with the above concentration. To ensure that the sample is in sufficient contact with the bacterial solution, place the flask in a constant temperature shaker at a certain temperature (25±1℃) and a certain speed (250-300 rpm) for 1 h.

[0048] Diluted culture: after the shaking is completed, take 1 mL of the bacterial solution from the flask and dilute it 10 times with water. Inoculate the diluted bacterial solution into agar culture medium and incubate in an incubator for 24 h.

[0049] Result calculation: compare the number of colonies in the sample group and the blank control group (the difference from the sample group is only that no membrane sample to be tested is added), calculate the antibacterial rate, and the formula is:

[0050] R(%)=(number of colonies in the blank control group-number of colonies in the sample group) / number of colonies in the blank control group×100%

[0051] Tazobactam acid is an Aladdin product.

[0052] Other reagents are purchased from Tianjin Kemio Chemical Reagents Co., Ltd.

[0053] The room temperature in the following examples is 25℃.

[0054] Example 1

[0055] 1. Preparation of polysulfone base membrane: Polysulfone (Aldrich product, product catalog number: P303213, average Mw ~ 35,000) was dissolved in N,N-dimethylformamide to obtain a 17wt% polysulfone casting solution. Then the filtered and degassed polysulfone casting solution was uniformly coated on a polyester non-woven fabric (Changzhou Kangjiet Special Non-woven Fabric Co., Ltd. product, product catalog number: GL77-A-15, thickness 90-100 μm) and then transferred into water to form a membrane by phase inversion. After water washing, a polysulfone base membrane was obtained. The pore size of the prepared polysulfone base membrane was between 5-100 nm, and the thickness was 130-150 μm (measured by micrometer).

[0056] 2. The polysulfone base membrane was contacted with a 2.5wt% aqueous solution of m-phenylenediamine for 1 min, and then the excess aqueous solution on the surface was poured off and dried.

[0057] 3. The membrane treated in step 2 was contacted with a 1.0wt% solution of trimesoyl chloride in n-hexane for 1 min, so that the m-phenylenediamine and trimesoyl chloride reacted by interfacial polymerization on the surface of the polysulfone base membrane. The excess organic solution was poured off and uniformly blown by air knife until no residual solvent was left on the membrane surface. Thus, a polyamide reverse osmosis membrane was formed. The thickness of the layer formed by interfacial polymerization was 100-300 nm (measured by scanning electron microscope).

[0058] 4. The polyamide reverse osmosis membrane was immersed in a 0.2wt% aqueous solution of tazobactam acid, and reacted at room temperature for 45 min. Then the membrane was taken out and washed with water to obtain an antibacterial reverse osmosis membrane.

[0059] Examples 2-10

[0060] The antibacterial reverse osmosis membrane was prepared according to the method of Example 1, except that the reagents and conditions were as shown in Table 1.

[0061] Comparative Example

[0062] The difference between this comparative example and Example 1 was only that in step 4, the aqueous solution of tazobactam acid was replaced by pure water.

[0063] Test Example 1

[0064] The reverse osmosis membranes prepared in Examples 1-10 and the comparative example were tested for antibacterial property, and the results of the antibacterial rate are shown in Table 1.

[0065] Test Example 2

[0066] The desalination rate and the permeation flux within 10 minutes were tested.

[0067] The results of the desalination rate and the permeation flux are shown in Table 1.

[0068] Table 1

[0069] Table 1

[0070] From the test results of the examples and comparative examples, it can be seen that the antibacterial rates of the membranes prepared by using different concentrations of the tazobactam acid are all much higher than those of the comparative examples, indicating that the membranes prepared by using the tazobactam acid in the examples have excellent antibacterial performance; in addition, the reverse osmosis membranes prepared by grafting modification of the tazobactam acid on the surface of the nascent polyamide membranes can also maintain the original separation performance of the reverse osmosis membranes.

[0071] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, without departing from the method of the present application, a number of improvements and supplements can also be made, which should also be considered as the protection scope of the present application.

Claims

1. A bacteriostatic reverse osmosis membrane, comprising a non-woven fabric substrate, a porous support layer and a separation layer, characterized in that: the porous support layer is a composite ultrafiltration membrane formed by phase inversion of polysulfone on the non-woven fabric substrate; and the separation layer is a polyamide membrane obtained by interfacial polymerization of an aromatic polyamine compound and an aromatic acid chloride compound on the porous support layer, and then grafting modification of tazobactam acid. 2.The bacteriostatic reverse osmosis membrane according to claim 1, characterized in that: the non-woven fabric substrate is selected from one of a polyester non-woven fabric, a polypropylene non-woven fabric and a polyethylene non-woven fabric; the aromatic polyamine compound is selected from one or more of m-phenylenediamine, m-phenylenediamine and p-phenylenediamine; and / or the aromatic acid chloride compound is selected from one or more of m-phenylenediamine, p-phenylenediamine and m-phenylenediamine. The thickness of the non-woven fabric substrate is 90-100 μm; the pore size of the porous support layer is 5-100 nm, and the thickness is 30-60 μm; and / or the thickness of the separation layer is 100-300 nm. The bacteriostatic rate of the bacteriostatic reverse osmosis membrane is more than 10%. 5.A method for preparing the bacteriostatic reverse osmosis membrane according to any one of claims 1-4, comprising the following steps: S1, dissolving polysulfone in N, N-dimethylformamide to obtain a 15-20 wt% polysulfone casting solution, uniformly coating the casting solution on the non-woven fabric substrate, and then phase-inverting into a composite ultrafiltration membrane in water to form a porous support layer on the non-woven fabric substrate; S2, contacting the membrane treated in step S1 with an aqueous solution of an aromatic polyamine compound, then discarding the excess aqueous solution on the surface and air-drying; S3, contacting the membrane treated in step S2 with an organic solution of an aromatic acid chloride compound, allowing interfacial polymerization of the aromatic polyamine compound and the aromatic acid chloride compound on the porous support layer, discarding the excess organic solution and removing the residual organic solvent on the surface to form a polyamide reverse osmosis membrane; S4, immersing the polyamide reverse osmosis membrane in an aqueous solution of tazobactam acid for reaction, taking out the membrane and washing with water to obtain the bacteriostatic reverse osmosis membrane. In step S2, the concentration of the aqueous solution of the aromatic polyamine compound is 1.0-5.0 wt%; and / or the contacting time is 0.5-2.0 min. In step S3, the concentration of the organic solution of the aromatic acid chloride compound is 0.1-2.0 wt%; the solvent of the organic solution of the aromatic acid chloride compound is one or more of hexane, heptane, decane, cyclohexane and ethylcyclohexane; and / or the contacting time is 0.5-2.0 min.

3. The bacteriostatic reverse osmosis membrane according to claim 1 or 2, characterized in that: 8.The method according to any one of claims 5-7, characterized in that: the non-woven fabric substrate is selected from one of a polyester non-woven fabric, a polypropylene non-woven fabric and a polyethylene non-woven fabric; the aromatic polyamine compound is selected from one or more of m-phenylenediamine, m-phenylenediamine and p-phenylenediamine; and / or the aromatic acid chloride compound is selected from one or more of m-phenylenediamine, p-phenylenediamine and m-phenylenediamine. ​ ​ 4. The bacteriostatic reverse osmosis membrane according to any one of claims 1-3, characterized in that: ​ ​ ​ ​ ​ ​ 6. The method of claim 5, wherein: ​ ​ 7. The method of manufacturing according to claim 5 or 6, characterized in that: ​ ​ ​ ​ ​ ​ ​ 9. The method of any one of claims 5-8, wherein: In step S4, the concentration of the aqueous solution of the acid of talabstatin is 0.1-0.3wt%; and / or The reaction time is 30-60min.

10. Use of the bacteriostatic reverse osmosis membrane according to any one of claims 1-4 for the preparation of a water treatment module and / or in a water treatment process.

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