Anti-pollution composite membrane, preparation method thereof and reverse osmosis membrane

Abstract

The invention discloses an anti-pollution composite membrane, a preparation method thereof and a reverse osmosis membrane, and relates to the technical field of water treatment separation membranes, the anti-pollution composite membrane comprises a support membrane and a separation function layer formed on the support membrane; wherein the separation function layer comprises a polyamide crosslinking layer containing an acyl halide group and a compound containing an aminophosphonic acid group, and an amino group in the compound containing the aminophosphonic acid group and the acyl halide group in the polyamide crosslinking layer are bonded with each other through an amido bond. According to the anti-pollution composite membrane provided by the invention, the polyamide crosslinking layer containing the acyl halide group and the compound containing the amino phosphonic acid group are bonded through the amido bond, so that the phosphonic acid group is grafted on the polyamide crosslinking layer, the hydrophilicity of the polyamide crosslinking layer is improved, and the membrane is easy to form a hydration layer when being subjected to separation treatment; therefore, pollutants are prevented from being adsorbed or deposited on the surface of the membrane, the anti-pollution capacity of the membrane is improved, and the service life of the membrane is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment separation membranes, in particular to an anti-pollution composite membrane and a preparation method thereof and a reverse osmosis membrane. Background Art

[0002] Membrane technology is one of the fastest growing and most attractive separation technologies in recent decades and has been widely used in many fields such as gas separation, water treatment, and chemical separation processes.

[0003] Membrane fouling is a common and serious problem in membrane separation processes. When membranes are contaminated by organic matter, inorganic matter, particulate matter or microorganisms, they not only affect the separation efficiency of the membrane, but also increase operating costs and energy consumption. Membrane fouling can occur in a variety of water treatment technologies, including reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF) and microfiltration (MF).

[0004] Regular cleaning is usually performed to maintain the cleanliness of the membrane and avoid affecting the membrane separation efficiency. However, frequent cleaning will shorten the service life of the membrane and ultimately lead to increased operating costs. Summary of the invention

[0005] The main purpose of the present invention is to provide an anti-pollution composite membrane and a preparation method thereof and a reverse osmosis membrane, aiming to solve the problem in the prior art that frequent cleaning of the separation membrane will shorten the service life of the separation membrane.

[0006] To achieve the above-mentioned object, the present invention provides an anti-pollution composite membrane, comprising a support membrane and a separation functional layer formed on the support membrane;

[0007] The separation function layer comprises a polyamide cross-linked layer containing acyl halide groups and a compound containing aminophosphonic acid groups, and the amino groups in the compound containing aminophosphonic acid groups are bonded to the acyl halide groups in the polyamide cross-linked layer through amide bonds.

[0008] In one embodiment, the surface of the separation functional layer has a root mean square surface roughness of 41 to 53 nm.

[0009] The present invention also provides a method for preparing an anti-pollution composite membrane, comprising the following steps:

[0010] S10, obtaining a support membrane, mixing an aqueous solution of a multifunctional amine with the support membrane, so that the aqueous solution of the multifunctional amine forms a liquid film on the surface of the support membrane, and obtaining a membrane intermediate;

[0011] S20, mixing the organic solution of the multifunctional acyl halide with the membrane intermediate, performing an interfacial polymerization reaction, and drying to obtain a primary membrane; a polyamide cross-linked layer containing unreacted acyl halide groups is formed on the surface of the primary membrane;

[0012] S30, mixing the primary membrane with an aqueous solution of a compound containing an aminophosphonic acid group to perform an amide reaction to obtain the anti-pollution composite membrane.

[0013] In one embodiment, in step S10, the support membrane includes a polyester non-woven fabric and a polysulfone material layer disposed on a surface of the polyester non-woven fabric.

[0014] In one embodiment, in step S10:

[0015] The polyfunctional amine includes one or more of m-phenylenediamine, p-phenylenediamine, and 1,3,5-triaminobenzene; and / or,

[0016] The mixing time is 90 to 150 seconds.

[0017] In one embodiment, in step S20:

[0018] The polyfunctional acyl halide comprises trimesoyl chloride of 1,3,5-benzenetricarboxylic acid; and / or,

[0019] The organic solvent in the organic solution is Isopar G, Isopar L or n-hexane; and / or,

[0020] The interfacial polymerization reaction time is 30 to 90 seconds.

[0021] In one embodiment, in step S20: the drying temperature is 80-100° C.; and the drying time is 5-7 min.

[0022] In one embodiment, the molar ratio of the amino groups of the polyfunctional amine in the aqueous solution of the polyfunctional amine to the acyl halide groups of the polyfunctional acyl halide in the organic solution of the polyfunctional acyl halide is (24-33):1.

[0023] In one embodiment, in step S30:

[0024] The compound containing an aminophosphonic acid group includes one or more of (aminomethyl)phosphonic acid, 2-aminoethylphosphonic acid, and 4-aminobutylphosphonic acid; and / or,

[0025] The amide reaction time is 1 to 5 minutes; and / or,

[0026] The concentration of the compound containing aminophosphonic acid groups is 0.1-1.0 mol / L.

[0027] The present invention also provides a reverse osmosis membrane, comprising the aforementioned anti-pollution composite membrane, or an anti-pollution composite membrane prepared by the aforementioned method for preparing the anti-pollution composite membrane.

[0028] In the technical solution of the present invention, a polyamide cross-linked layer containing acyl halide groups is bonded to a compound containing aminophosphonic acid groups through an amide bond, so that the phosphonic acid groups are grafted onto the polyamide cross-linked layer, thereby improving the hydrophilicity of the polyamide cross-linked layer and making it easy for the membrane to form a hydration layer when performing separation treatment, thereby preventing pollutants from being adsorbed or deposited on the membrane surface, improving the membrane's anti-pollution ability, and extending the membrane's service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 This is a surface electron microscope image of the anti-pollution composite membrane prepared in Example 1 provided by the present invention;

[0031] Figure 2 This is a cross-sectional electron microscope image of the anti-pollution composite membrane prepared in Example 1 provided by the present invention;

[0032] Figure 3 This is a surface electron microscope image of the anti-pollution composite membrane prepared in Comparative Example 1 provided by the present invention;

[0033] Figure 4 This is a cross-sectional electron microscope image of the anti-pollution composite membrane prepared in Comparative Example 1 provided by the present invention.

[0034] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0035] To make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme in the embodiment of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiment, it is carried out according to the normal conditions or the conditions recommended by the manufacturer. If the reagents or instruments used do not specify the manufacturer, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes, taking "A and / or B" as an example, including scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical schemes between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in the field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist, and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention.

[0036] Membrane technology is one of the fastest growing and most attractive separation technologies in recent decades and has been widely used in many fields such as gas separation, water treatment, and chemical separation processes.

[0037] Membrane fouling is a common and serious problem in membrane separation processes. When membranes are contaminated by organic matter, inorganic matter, particulate matter or microorganisms, they not only affect the separation efficiency of the membrane, but also increase operating costs and energy consumption. Membrane fouling can occur in a variety of water treatment technologies, including reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF) and microfiltration (MF).

[0038] Regular cleaning is usually performed to maintain the cleanliness of the membrane and avoid affecting the membrane separation efficiency. However, frequent cleaning will shorten the service life of the membrane and ultimately lead to increased operating costs.

[0039] In view of this, the present invention provides an anti-pollution composite membrane, comprising a support membrane and a separation functional layer formed on the support membrane;

[0040] The separation function layer comprises a polyamide cross-linked layer containing acyl halide groups and a compound containing aminophosphonic acid groups, and the amino groups in the compound containing aminophosphonic acid groups are bonded to the acyl halide groups in the polyamide cross-linked layer through amide bonds.

[0041] In the technical solution of the present invention, the polyamide cross-linked layer containing acyl halide groups is bonded to the compound containing aminophosphonic acid groups through an amide bond, so that the phosphonic acid groups are grafted onto the polyamide cross-linked layer, thereby improving the hydrophilicity of the polyamide cross-linked layer, so that when the membrane is subjected to separation treatment, it is easy to form a hydration layer, thereby preventing pollutants from being adsorbed or deposited on the membrane surface, improving the anti-pollution ability of the membrane, and extending the service life of the membrane. Preferably, the anti-pollution composite membrane of the present invention is used as a reverse osmosis membrane for seawater desalination.

[0042] In some embodiments of the present invention, the surface root mean square roughness of the separation functional layer is 41-53 nm. The root mean square surface roughness within the above range can ensure good anti-pollution ability.

[0043] The present invention also provides a method for preparing an anti-pollution composite membrane, comprising the following steps:

[0044] S10, obtaining a support membrane, mixing an aqueous solution of a multifunctional amine with the support membrane, so that the aqueous solution of the multifunctional amine forms a liquid film on the surface of the support membrane, and obtaining a membrane intermediate;

[0045] S20, mixing the organic solution of the multifunctional acyl halide with the membrane intermediate, performing an interfacial polymerization reaction, and drying to obtain a primary membrane; a polyamide cross-linked layer containing unreacted acyl halide groups is formed on the surface of the primary membrane;

[0046] S30, mixing the primary membrane with an aqueous solution of a compound containing an aminophosphonic acid group to perform an amide reaction to obtain the anti-pollution composite membrane.

[0047] In the technical scheme of the present invention, the amino groups of the multifunctional amine in the membrane intermediate and the amide groups of the multifunctional acyl halide undergo polymerization reaction at the interface of the supporting membrane. Since the multifunctional amine has multiple amino groups and the multifunctional acyl halide has multiple amide groups, a polyamide polymer can be formed, and the polyamide polymer contains unreacted acyl halide groups, which can undergo amide reaction with the amino groups in the compound containing aminophosphonic acid groups, and the phosphonic acid is grafted on the polyamide polymer to obtain an anti-pollution composite membrane. The preparation method uses fewer types and amounts of chemical reagents, is green and environmentally friendly, reduces costs, is easier to industrialize, and can obtain a membrane with good anti-pollution performance and service life.

[0048] In some embodiments of the present invention, in step S10, the support membrane includes a polyester nonwoven fabric and a polysulfone material layer arranged on the surface of the polyester nonwoven fabric. Wherein, the polyester nonwoven fabric can provide good mechanical support, ensure that the membrane will not deform or break under high pressure or high flow conditions, and can initially filter large particulate matter, reducing the burden of the subsequent polysulfone material layer. The polysulfone material layer can achieve more refined filtration, remove smaller particles and microorganisms, and improve filtration efficiency and purity. It should be noted that the subsequent interfacial reaction occurs in the polysulfone material layer.

[0049] In some embodiments of the present invention, in step S10: the multifunctional amine includes one or more of m-phenylenediamine, p-phenylenediamine, and 1,3,5-triaminobenzene. The multifunctional amine can provide multiple amino groups, providing conditions for the formation of polyamide polymers.

[0050] In some embodiments of the present invention, in step S10: the mixing time is 90 to 150 seconds. The mixing time within the above range can ensure that there is sufficient multifunctional amine in the membrane intermediate for subsequent reactions.

[0051] In some embodiments of the present invention, in step S20: the multifunctional acyl halide comprises trimesoyl chloride of 1,3,5-benzenetricarboxylic acid. The multifunctional acyl halide can provide multiple acyl halide groups, providing conditions for the formation of polyamide polymers and for the subsequent introduction of phosphonic acid groups.

[0052] In some embodiments of the present invention, in step S20: the organic solvent in the organic solution is Isopar G, Isopar L or n-hexane. The above organic solvent can dissolve the multifunctional acyl halide well and promote the formation of the polyamide cross-linking layer.

[0053] In some embodiments of the present invention, in step S20, the interfacial polymerization reaction time is 30 to 90 seconds. The interfacial polymerization reaction time within the above range can ensure that the multifunctional amine and the multifunctional acyl halide undergo a relatively sufficient interfacial polymerization reaction to form a better polyamide cross-linked layer.

[0054] In some embodiments of the present invention, in step S20: the drying temperature is 80-100° C.; the drying time is 5-7 minutes. The drying temperature and drying time within the above range can ensure that the polyamide cross-linking layer is further stabilized and the performance of the membrane is improved.

[0055] In some embodiments of the present invention, the molar ratio of the amino groups of the multifunctional amine in the aqueous solution of the multifunctional amine to the acyl halide groups of the multifunctional acyl halide in the organic solution of the multifunctional acyl halide is (24-33): 1. The molar ratio within the above range can ensure the formation of a good polyamide cross-linked layer, and there are unreacted acyl halide groups on the polyamide cross-linked layer.

[0056] In some embodiments of the present invention, in step S30: the compound containing aminophosphonic acid groups includes one or more of (aminomethyl)phosphonic acid, 2-aminoethylphosphonic acid, and 4-aminobutylphosphonic acid. The above-mentioned compound containing aminophosphonic acid groups is easily soluble in water and can react well with unreacted acyl halide groups in the polyamide cross-linking layer to form an amide, thereby allowing the phosphonic acid groups to be grafted into the polyamide cross-linking layer.

[0057] In some embodiments of the present invention, in step S30, the amide reaction time is 1 to 5 minutes. The amide reaction time within the above range can ensure a more thorough amide reaction, so that more phosphonic acid groups are grafted on the polyamide cross-linking layer, thereby improving the anti-fouling ability of the membrane.

[0058] In some embodiments of the present invention, in step S30: the concentration of the compound containing aminophosphonic acid groups is 0.1-1.0 mol / L. The concentration within the above range can make more phosphonic acid groups grafted on the polyamide cross-linking layer, thereby improving the anti-fouling ability of the membrane.

[0059] The present invention also provides a reverse osmosis membrane, including the aforementioned anti-pollution composite membrane, or an anti-pollution composite membrane prepared by the aforementioned method for preparing the anti-pollution composite membrane. The reverse osmosis membrane includes the anti-pollution composite membrane, and thus has all the beneficial effects of the aforementioned anti-pollution composite membrane and the method for preparing the anti-pollution composite membrane, which will not be described one by one here.

[0060] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0061] Example 1

[0062] A method for preparing an anti-pollution composite membrane comprises the following steps:

[0063] S10, fixing the support membrane (polyester non-woven fabric and the polysulfone material layer disposed thereon) on a 20×10 cm silica gel frame, and then pouring a 3.5% (w / v) m-phenylenediamine aqueous solution prepared by triethylamine and camphorsulfonic acid at a pH of 10.5 onto the surface of the support membrane (i.e., the polysulfone material layer) to allow it to soak for 2 min, and then pouring off the excess solution to obtain a membrane intermediate;

[0064] S20, contacting the membrane intermediate with an Isopar G solution containing 0.2% (wt%) trimesoyl chloride for 1 min, removing excess organic solution on the surface, and then placing the membrane intermediate in an oven for heat treatment at 90° C. for 6 min to obtain a primary membrane;

[0065] S30. Rinse the primary membrane with Isopar G for 3 times, and after drying, pour 0.7 mol / L 4-aminobutylphosphonic acid aqueous solution on the membrane surface, soak for 5 minutes, remove excess solution, soak in 1% sodium carbonate solution for 2 minutes, and then wash the surface with deionized water to obtain an anti-pollution composite membrane, which is stored in deionized water for later use.

[0066] Example 2

[0067] Compared with Example 1, Example 2 is different in that:

[0068] In step S30, the 0.7 mol / L aqueous solution of 4-aminobutylphosphonic acid is replaced with a 0.5 mol / L aqueous solution of (aminomethyl)phosphonic acid.

[0069] Example 3

[0070] Compared with Example 1, Example 3 is different in that:

[0071] In step S30, the 0.7 mol / L aqueous solution of 4-aminobutylphosphonic acid is replaced with a 0.5 mol / L aqueous solution of 2-aminoethylphosphonic acid.

[0072] Example 4

[0073] Compared with Example 1, Example 4 is different in that:

[0074] In step S30, the 0.7 mol / L 4-aminobutylphosphonic acid aqueous solution is replaced with a 0.5 mol / L 4-aminobutylphosphonic acid aqueous solution.

[0075] Example 5

[0076] Compared with Example 1, Example 5 is different in that:

[0077] In step S30, the 0.7 mol / L 4-aminobutylphosphonic acid aqueous solution is replaced with a 0.1 mol / L 4-aminobutylphosphonic acid aqueous solution.

[0078] Example 6

[0079] Compared with Example 1, Example 6 is different in that:

[0080] In step S30, the 0.7 mol / L 4-aminobutylphosphonic acid aqueous solution is replaced with a 1.0 mol / L 4-aminobutylphosphonic acid aqueous solution.

[0081] Example 7

[0082] Compared with Example 1, Example 7 is different in that:

[0083] In step S30, a 0.7 mol / L 4-aminobutylphosphonic acid aqueous solution is poured onto the membrane surface and soaked for 1 min.

[0084] Example 8

[0085] Compared with Example 1, Example 8 is different in that:

[0086] In step S30, a 0.7 mol / L 4-aminobutylphosphonic acid aqueous solution is poured onto the membrane surface and soaked for 1 min.

[0087] Comparative Example 1

[0088] Compared with Example 1, Comparative Example 1 is different in that:

[0089] The primary membrane was prepared according to steps S10 and S20 in Example 1, except that in step S30, the primary membrane was rinsed three times with Isopar G and dried, and then directly immersed in a 1% sodium carbonate solution for 2 minutes, and then the surface was washed with deionized water to obtain an anti-pollution composite membrane, which was stored in deionized water for later use.

[0090] Performance Testing

[0091] The surface and cross-sectional microstructure of the anti-pollution composite membrane prepared in Example 1 and the comparative example were observed. Figure 1 , Figure 2 , Figure 3 and Figure 4 shown.

[0092] Depend on Figure 1 It can be seen that the surface electron microscope image of the anti-pollution composite membrane in Example 1 shows that the polyamide is mainly accumulated in small spheres and is dense, with some strip-like nodular structures on it. Figure 2 It can be seen that the cross-sectional electron microscopy image of the anti-pollution composite membrane in Example 1 has no obvious protrusions and has a relatively good surface flatness.

[0093] from Figure 3 It can be seen that the polyamide in Comparative Example 1 is accumulated in the form of small spheres; Figure 4 It can be seen that the cross-sectional electron microscopy image of comparative example 1 shows that the thickness is slightly reduced, the surface flatness is increased, the roughness of the membrane is reduced, and the smoothness is increased compared with embodiment 1.

[0094] The anti-pollution composite membranes prepared in Examples 1 to 8 and Comparative Example 1 were tested for flux F, NaCl retention rate R, contact angle, flux recovery rate FFR, and Zeta potential, and the relevant results are recorded in Table 1.

[0095] The specific test method is: operating temperature 25℃, test solution is 32800mg / L NaCl aqueous solution, operating pressure is 5.55MPa, this test method is suitable for testing the performance of high-pressure reverse osmosis membranes. Before the membrane performance test, the membrane needs to be pre-pressed with pure water at a pressure of 4MPa for 4 hours, and three parallel samples of all membranes are tested, and then the average value is taken.

[0096] (1) The membrane flux F is calculated using the following formula:

[0097]

[0098] Among them, V is the volume of water permeating through the effective area of ​​the membrane per unit time, A is the effective area of ​​the membrane, and t is the time, and its unit is Lm -2 h -1 (LMH).

[0099] (2) The membrane retention rate R is calculated using the following formula:

[0100]

[0101] Among them C f and C p They are the salt concentrations in the mother liquor and the permeate, respectively, which can be obtained indirectly by testing the conductivity of the salt solution, which is measured by a conductivity meter.

[0102] (3) Contact angle: The image of a water drop on the membrane surface is taken by the drop method, and the contact angle is calculated using image analysis software;

[0103] (4) Zeta potential: The streaming potential of the membrane surface was tested by SurPASS electrodynamic analyzer;

[0104] (5) Flux recovery rate (FFR): obtained through pollution test. The pollution test process is as follows: operating temperature 25°C, the contamination solution is a mixed aqueous solution of 32800 mg / L NaCl and 1% bovine serum albumin, and the operating pressure is 5.55 MPa. The initial membrane flux of the test is F w0 After the polluted solution was run for 24 hours, the flux of the membrane was tested after washing with pure water for 0.5 hours. wt The membrane flux recovery rate FRR is calculated by the following formula:

[0105]

[0106] Table 1 Performance characterization of anti-fouling composite membrane

[0107]

[0108] From the results in Table 1, it can be seen that the acyl chloride groups remaining on the surface of the anti-pollution composite membrane react with aminophosphonic acid to introduce phosphonic acid groups into the membrane surface, which increases the hydrophilicity of the membrane surface, improves the permeability and retention rate of the membrane, and also increases the charge of the membrane surface. From the data of Examples 1 to 8 and Comparative Example 1, it can be seen that phosphonic acid (Example) has stronger charge and wettability than carboxylic acid (Comparative Example 1), so phosphonic acid is a suitable group to improve the hydrophilicity of the membrane. The hydrophilic surface can absorb more water molecules, which can form a layer of water film on the membrane surface, play a barrier role, hinder the deposition of bovine serum albumin on the membrane surface, and the formation of a surface hydration layer, which improves the anti-pollution property of the membrane.

[0109] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. An anti-pollution composite membrane, characterized in that: It includes a support membrane and a separation function layer formed on the support membrane; The separation function layer comprises a polyamide cross-linked layer containing acyl halide groups and a compound containing aminophosphonic acid groups, and the amino groups in the compound containing aminophosphonic acid groups are bonded to the acyl halide groups in the polyamide cross-linked layer through amide bonds.

2. The anti-pollution composite membrane according to claim 1, characterized in that: The root mean square surface roughness of the surface of the separation functional layer is 41 to 53 nm.

3. A method for preparing an anti-pollution composite membrane, characterized in that: The following steps are involved: S10, obtaining a support membrane, mixing an aqueous solution of a multifunctional amine with the support membrane, so that the aqueous solution of the multifunctional amine forms a liquid film on the surface of the support membrane, and obtaining a membrane intermediate; S20, mixing the organic solution of the multifunctional acyl halide with the membrane intermediate, performing an interfacial polymerization reaction, and drying to obtain a primary membrane; a polyamide cross-linked layer containing unreacted acyl halide groups is formed on the surface of the primary membrane; S30, mixing the primary membrane with an aqueous solution of a compound containing an aminophosphonic acid group to perform an amide reaction to obtain the anti-pollution composite membrane.

4. The method for preparing the anti-pollution composite membrane according to claim 3, characterized in that: In step S10, the support membrane includes a polyester non-woven fabric and a polysulfone material layer disposed on the surface of the polyester non-woven fabric.

5. The method for preparing the anti-pollution composite membrane according to claim 3, characterized in that: In step S10: The polyfunctional amine includes one or more of m-phenylenediamine, p-phenylenediamine, and 1,3,5-triaminobenzene; and / or, The mixing time is 90 to 150 seconds.

6. The method for preparing the anti-pollution composite membrane according to claim 3, characterized in that: In step S20: The polyfunctional acyl halide comprises trimesoyl chloride of 1,3,5-benzenetricarboxylic acid; and / or, The organic solvent in the organic solution is Isopar G, Isopar L or n-hexane; and / or, The interfacial polymerization reaction time is 30 to 90 seconds.

7. The method for preparing the anti-pollution composite membrane according to claim 3, characterized in that: In step S20: the drying temperature is 80-100° C.; the drying time is 5-7 minutes.

8. The method for preparing the anti-pollution composite membrane according to claim 3, characterized in that: The molar ratio of the amino groups of the polyfunctional amine in the aqueous solution of the polyfunctional amine to the acyl halide groups of the polyfunctional acyl halide in the organic solution of the polyfunctional acyl halide is (24-33):

1.

9. The method for preparing the anti-pollution composite membrane according to claim 3, characterized in that: In step S30: The compound containing an aminophosphonic acid group includes one or more of (aminomethyl)phosphonic acid, 2-aminoethylphosphonic acid, and 4-aminobutylphosphonic acid; and / or, The amide reaction time is 1 to 5 minutes; and / or, The concentration of the compound containing aminophosphonic acid groups is 0.1-1.0 mol / L.

10. A reverse osmosis membrane, characterized in that: The invention comprises the anti-pollution composite membrane as claimed in any one of claims 1 to 2, or the anti-pollution composite membrane prepared by the method for preparing the anti-pollution composite membrane as claimed in any one of claims 3 to 9.

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