Bacteriostatic reverse osmosis membrane as well as preparation method and application thereof

Abstract

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

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment and relates to an antibacterial reverse osmosis membrane and a preparation method and application thereof. Background Art

[0002] Reverse osmosis technology has developed rapidly in my country since the 1990s and is currently widely used in various industries, especially in 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, with 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 bacteria and other pollution. Therefore, reverse osmosis membranes need stronger antibacterial properties.

[0003] CN114917776B achieves dual antibacterial effect by coating a protective layer containing carboxymethyl chitosan quaternary ammonium salt / titanium dioxide complex on the reverse osmosis membrane surface, utilizing 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 properties, such as drinking water production, wastewater treatment, etc., and can effectively inhibit the growth and reproduction of microorganisms to ensure water quality safety. CN115228291B introduces stilbene compounds and aromatic quaternary ammonium salt blends containing sulfonic acid and amino structures on the functional layer surface of reverse osmosis membrane. These compounds have strong antibacterial properties, can destroy bacterial cell walls or cell membranes, and cause bacterial death. It is widely used in water treatment fields such as wastewater reuse and industrial water supply, and can effectively inhibit the attachment and growth of microorganisms while maintaining high desalination rate and water flux, and extend the service life of the membrane. CN112426884A obtains antibacterial properties through specific post-treatment processes (such as grafting antibacterial groups, coating antibacterial layers, etc.) for water treatment scenarios that require chlorine resistance, excellent anti-pollution performance and high antibacterial performance, such as seawater desalination, boiler water supply, etc. CN107303470B achieves antibacterial effect by coating a polymer cross-linked coating containing attapulgite / silicon dioxide-nanosilver composite inorganic powder on a reverse osmosis membrane. Nanosilver has a broad spectrum of antibacterial properties, can destroy the DNA structure of bacteria, and inhibit their growth and reproduction. It is widely used in water treatment fields that require high-efficiency antibacterial properties, such as drinking water production, medical water treatment, etc.

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

[0005] The object of the present invention is to provide an antibacterial reverse osmosis membrane in view of the above-mentioned deficiencies in the prior art.

[0006] In a first aspect, the present invention provides an antibacterial 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 by polysulfone on the non-woven fabric base layer through a phase inversion method; and

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

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

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

[0011] The aromatic acyl chloride compound is selected from one or more of trimesoyl chloride, terephthaloyl chloride and isophthaloyl chloride.

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

[0013] The porous support layer has a pore size of 5-100 nm and a thickness of 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 antibacterial reverse osmosis membranes, the antibacterial rate of the antibacterial reverse osmosis membrane is above 10%, for example, above 11%, above 12%, above 13%, above 14%, above 15%, above 16%, or above 17%.

[0016] In a second aspect, the present invention provides a method for preparing any of the above-mentioned antibacterial reverse osmosis membranes, comprising the following steps:

[0017] S1, dissolving polysulfone in N,N-dimethylformamide to obtain a polysulfone casting solution of 15-20wt% (e.g., 15, 16, 17, 18, 19, 20wt%, or any value or range between these values), uniformly applying the polysulfone casting solution on the non-woven fabric substrate, and then entering water to phase-convert into a composite ultrafiltration membrane, thereby forming a porous support layer on the non-woven fabric substrate;

[0018] S2, contacting the film treated in step S1 with an aqueous solution of an aromatic polyamine compound, then pouring off excess aqueous solution on the surface and drying;

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

[0020] S4, immersing the polyamide reverse osmosis membrane in an aqueous solution of tazobactam acid for reaction, taking out the membrane and washing it with water to obtain the antibacterial 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 contact time is 0.5-2 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 therebetween.

[0023] In some embodiments, in any of the above-described preparation methods, in step S3, the concentration of the organic solution of the aromatic acyl chloride compound is 0.1-2.0 wt %, 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, 2.0 wt %, or any value or range between these values;

[0024] The solvent of the organic solution of the aromatic acyl chloride compound is selected from one or more of hexane, heptane, decane, cyclohexane, and ethylcyclohexane, for example, hexane, heptane, decane, cyclohexane, and ethylcyclohexane can be mixed 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 therebetween.

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

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

[0028] The aromatic acyl chloride compound is selected from one or more of trimesoyl chloride, terephthaloyl chloride and isophthaloyl chloride.

[0029] In some embodiments, in any of the above-described preparation methods, in step S4, the concentration of the aqueous solution of tazobactam acid is 0.1-0.3 wt%, such as 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 therebetween, and the reaction temperature is room temperature, for example 15-25°C, for example 25°C.

[0031] In a third aspect, the present invention provides use of any of the above-mentioned antibacterial 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, a wide enzyme inhibition spectrum, good stability, and excellent antibacterial properties. The present invention grafts tazobactam acid onto the membrane surface through polycondensation reaction between the acyl chloride groups remaining on the surface of the polyamide reverse osmosis membrane and tazobactam acid, so that the membrane is modified and has an antibacterial effect.

[0033] It should be pointed out that the "contact" in the present invention can be to immerse the membrane in the corresponding solution and then take it out, or to pour or apply the corresponding solution on the membrane surface, or a combination of the two and other common "contact" methods in the art. The key is to coat the corresponding reaction materials on the membrane surface to prepare for subsequent grafting. The present invention prefers interfacial contact, so that interfacial polymerization reaction preferably occurs at the interface. Such "contact" methods are all understandable to those skilled in the art and should be within the scope of protection of the present invention.

[0034] The beneficial effects of the present invention are:

[0035] The invention grafts tazobactam acid on the surface of the nascent polyamide membrane, so that the prepared reverse osmosis membrane has excellent antibacterial performance while maintaining the original separation performance, and the antibacterial rate can be as high as 18.4%.

[0036] In the water treatment process, the use of the antibacterial reverse osmosis membrane provided by the present invention can effectively reduce the cleaning frequency caused by biological contamination such as bacteria, extend its service life, and reduce maintenance costs. DETAILED DESCRIPTION

[0037] The present invention 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 invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional operations in the art, or according to the experimental methods recommended by the kit and instrument manufacturers. The reagents and biological materials used in the examples can be obtained from commercial sources unless otherwise specified.

[0038] Evaluation of salt rejection and permeate flux

[0039] Salt rejection rate and permeation flux are two important parameters for evaluating the separation performance of reverse osmosis membranes. The present invention evaluates the separation performance of reverse osmosis membranes according to GB / T32373-2015 "Test Method for Reverse Osmosis Membrane".

[0040] The desalination rate (R) is defined as: under certain operating conditions, the salt concentration of the feed solution (C f ) and the salt concentration in the permeate (C p ) and then divided by the feed solution salt concentration (C f ), the calculation formula is shown in formula (1).

[0041]

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

[0043] The operating conditions used in the reverse osmosis membrane performance measurement in the present invention are: the feed liquid is a 2000 ppm sodium chloride aqueous solution, the solution pH is 7.0±0.5, the operating pressure is 1.55 MPa, and the feed liquid temperature is 25°C.

[0044] The antibacterial test method is as follows:

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

[0046] Preparation of bacterial solution: Inoculate Escherichia coli into nutrient broth and culture at an appropriate temperature (37±1°C) until the required bacterial concentration of 10^6 CFU / mL (colony forming units per milliliter) is reached.

[0047] Sample inoculation: Place the prepared sample into a triangular flask containing the above-mentioned bacterial solution. To ensure that the sample is in full contact with the bacterial solution, place the bottle in a constant temperature oscillator and oscillate at a certain temperature (25±1℃) and a certain speed (250-300rpm) for 1 hour.

[0048] Dilution culture: After shaking, take 1 mL of bacterial solution from the flask and dilute it 10 times with water. Inoculate the diluted bacterial solution onto the agar medium and incubate it upside down in a constant temperature incubator for 24 hours.

[0049] Result calculation: By comparing the colony counts of the sample group and the blank control group (the only difference from the sample group is that no test film sample was added), the inhibition rate was calculated using the formula:

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

[0051] Tazobactam acid is a product of Aladdin.

[0052] Other reagents were purchased from Tianjin Kemeiou Chemical Reagent Co., Ltd.

[0053] The normal temperature in the following examples is 25°C.

[0054] Example 1

[0055] 1. Preparation of polysulfone bottom membrane: polysulfone (Aladdin product, product catalog number: P303213, average Mw ~ 35,000) was dissolved in N, N-dimethylformamide to obtain 17wt% polysulfone casting solution. Then the polysulfone casting solution after filtration and degassing was evenly coated on a polyester non-woven fabric (Changzhou Kangjie Special Non-woven Fabric Co., Ltd. product, product catalog number: GL77-A-15, thickness of 90-100μm), and then put into water for phase conversion into a membrane. After washing with water, a polysulfone bottom membrane was obtained. The prepared polysulfone bottom membrane had a pore size between 5-100nm and a thickness of 130-150μm (detected by a micrometer).

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

[0057] 3. The membrane treated in step 2 is contacted with a 1.0 wt % n-hexane solution of trimesoyl chloride for 1 min to allow interfacial polymerization of m-phenylenediamine and trimesoyl chloride to occur on the surface of the polysulfone base membrane. Excess organic solution is discarded and the membrane is evenly purged with an air knife until no residual solvent remains on the membrane surface, thereby forming a polyamide reverse osmosis membrane. The thickness of the layer formed by interfacial polymerization is 100-300 nm (measured by a scanning electron microscope).

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

[0059] Embodiment 2-10

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

[0061] Comparative Example

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

[0063] Test Example 1

[0064] The antibacterial property test was carried out using the reverse osmosis membranes prepared in Examples 1-10 and the comparative example. The antibacterial rate results are shown in Table 1.

[0065] Test Example 2

[0066] The salt rejection and permeate flux within 10 minutes were tested.

[0067] The results of salt rejection and permeate flux are shown in Table 1.

[0068] Table 1

[0069]

[0070] It can be seen from the test results of the embodiments and the comparative examples that the antibacterial rates of the membranes prepared using different concentrations of tazobactam acid are much higher than those of the comparative examples, indicating that the membranes prepared using tazobactam acid in the embodiments of the present invention have excellent antibacterial properties; in addition, the reverse osmosis membrane prepared by grafting tazobactam acid on the surface of the virgin polyamide membrane can also maintain the original separation performance of the reverse osmosis membrane.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. An antibacterial reverse osmosis membrane, comprising a non-woven fabric base layer, a porous support layer and a separation layer, characterized in that: The porous support layer is a composite ultrafiltration membrane formed by polysulfone on the non-woven fabric base layer through a phase inversion method; and The separation layer is a polyamide membrane obtained by interfacial polymerization of aromatic polyamine compounds and aromatic acyl chloride compounds on the porous support layer and then grafting modification with tazobactam acid.

2. The antibacterial reverse osmosis membrane according to claim 1, characterized in that: The non-woven fabric base layer is selected from one of polyester non-woven fabric, polypropylene non-woven fabric and polyethylene non-woven fabric; The aromatic polyamine compound is selected from one or more of m-phenylenediamine, mesitylenetriamine, and p-phenylenediamine; and / or The aromatic acyl chloride compound is selected from one or more of trimesoyl chloride, terephthaloyl chloride and isophthaloyl chloride.

3. The antibacterial reverse osmosis membrane according to claim 1 or 2, characterized in that: The thickness of the non-woven fabric base layer is 90-100 μm; The porous support layer has a pore size of 5-100 nm and a thickness of 30-60 μm; and / or The thickness of the separation layer is 100-300 nm.

4. The antibacterial reverse osmosis membrane according to any one of claims 1 to 3, characterized in that: The antibacterial rate of the antibacterial reverse osmosis membrane is above 10%.

5. The method for preparing the antibacterial reverse osmosis membrane according to any one of claims 1 to 4, comprising the following steps: S1, dissolving polysulfone in N,N-dimethylformamide to obtain a 15-20wt% polysulfone casting solution, evenly coating the solution on a non-woven fabric substrate, and then entering water to undergo phase conversion into a composite ultrafiltration membrane, thereby forming a porous support layer on the non-woven fabric substrate; S2, contacting the film treated in step S1 with an aqueous solution of an aromatic polyamine compound, then pouring off excess aqueous solution on the surface and drying; S3, contacting the membrane treated in step S2 with an organic solution of an aromatic acyl chloride compound, allowing the aromatic polyamine compound and the aromatic acyl chloride compound to undergo an interfacial polymerization reaction on the porous support layer, pouring off the excess organic solution, and removing the organic solvent remaining 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 it with water to obtain the antibacterial reverse osmosis membrane.

6. The preparation method according to claim 5, characterized in that: In step S2, the concentration of the aqueous solution of the aromatic polyamine compound is 1.0-5.0 wt %; and / or The contact time is 0.5-2.0 min.

7. The preparation method according to claim 5 or 6, characterized in that: In step S3, the concentration of the organic solution of the aromatic acyl chloride compound is 0.1-2.0 wt %; The solvent of the organic solution of the aromatic acyl chloride compound is one or more of hexane, heptane, decane, cyclohexane, and ethylcyclohexane; and / or The contact time is 0.5-2.0 min.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The non-woven fabric base layer is selected from one of polyester non-woven fabric, polypropylene non-woven fabric and polyethylene non-woven fabric; The aromatic polyamine compound is selected from one or more of m-phenylenediamine, mesitylenetriamine, and p-phenylenediamine; and / or The aromatic acyl chloride compound is selected from one or more of trimesoyl chloride, terephthaloyl chloride and isophthaloyl chloride.

9. The preparation method according to any one of claims 5 to 8, characterized in that: In step S4, the concentration of the aqueous solution of tazobactam acid is 0.1-0.3 wt %; and / or The reaction time is 30-60 min.

10. Use of the antibacterial reverse osmosis membrane according to any one of claims 1 to 4 in the preparation of a water treatment component and / or in a water treatment method.

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