Composite reverse osmosis membrane material as well as preparation method and application thereof

Abstract

The invention discloses a composite reverse osmosis membrane material as well as a preparation method and application thereof, and belongs to the technical field of reverse osmosis membrane preparation. The composite reverse osmosis membrane material comprises a polyolefin base membrane and a polyamide layer formed on the polyolefin base membrane, wherein a cross-linked network of the polyamide layer contains amino-polyethylene glycol-carboxyl transition metal salt. According to the composite reverse osmosis membrane material, amino-polyethylene glycol-carboxyl transition metal salt is chemically introduced into a cross-linked network of a polyamide layer, so that sulfur-containing, nitrogen-containing and other compound small molecules generated by microbial metabolism in a composite reverse osmosis membrane are effectively reduced, and the problem that an existing reverse osmosis water purifier is not used for a few days or even longer time; and in addition, the operation of arranging an activated carbon filter element at the rear part is omitted, so that the cost is saved.

Description

Technical Field

[0001] This application relates to a composite reverse osmosis membrane material, its preparation method, and its application, belonging to the field of reverse osmosis membrane preparation technology. Background Technology

[0002] Reverse osmosis water purifiers primarily rely on reverse osmosis membranes to filter harmful substances. Traditional reverse osmosis membranes are mainly based on polyester nonwoven fabric and a polysulfone layer as the base membrane, with a polyamide desalination layer formed by interfacial polymerization on the base membrane, creating a three-layer reverse osmosis membrane structure. However, this type of reverse osmosis membrane is thick, typically around 120μm, with highly porous membrane layers that easily breed microorganisms, leading to an off-flavor and poor taste in the purified water. Especially when a reverse osmosis water purifier has not been used for several days or longer, a noticeable odor or even a foul smell will appear when it is turned on again. The main reason for this is the low oxygen content in the water, allowing anaerobic or facultative anaerobic bacteria to multiply rapidly. While performing anaerobic respiration, these bacteria metabolize and produce small molecules containing sulfur and nitrogen atoms, such as hydrogen sulfide, methanethiol, thioesters, thioethers, and ammonia. Reverse osmosis membranes are ineffective at removing small molecule gaseous substances, so these sulfur- and nitrogen-containing small molecule compounds are the cause of the off-flavor in the purified water. Moreover, these substances have very low odor thresholds. For example, hydrogen sulfide has an odor threshold as low as 0.025 μg / L in water, and even trace amounts can cause water to have an unpleasant odor.

[0003] Currently, reverse osmosis water purifiers mainly rely on users to flush them with water for extended periods or add a post-activated carbon filter to absorb odors and improve taste. However, activated carbon adsorption is physical adsorption and is reversible. It is possible for the adsorbed material to desorb into the water. Moreover, activated carbon itself is a porous material, which can breed bacteria and cause odors over time. In addition, the post-activated carbon filter also takes up space in the water purifier.

[0004] Patent CN202322518U addresses the issue of odors appearing in water purifiers after prolonged periods of inactivity by periodically flushing the post-filter. However, this approach complicates the purifier design and wastes water. Patents CN115569538A and CN113797774A employ antibacterial agents grafted onto the reverse osmosis membrane surface for antibacterial action. However, after a period of use, scale and organic contaminants accumulate on the reverse osmosis membrane, rendering the antibacterial agents ineffective and allowing bacteria to continue multiplying, resulting in odors. Summary of the Invention

[0005] To address the aforementioned issues, a composite reverse osmosis membrane material is provided. This material introduces amino-polyethylene glycol-carboxyl transition metal salts into the cross-linked network of the polyamide layer, effectively reducing small molecules of sulfur- and nitrogen-containing compounds produced by microbial metabolism in the water after filtration. This solves the technical problem of existing reverse osmosis water purifiers producing odors and smells after being left unused for several days or even longer, and eliminates the need for a post-activated carbon filter, thus saving costs.

[0006] According to one aspect of this application, a composite reverse osmosis membrane material is provided, the composite reverse osmosis membrane material comprising a polyolefin-based membrane and a polyamide layer formed on the polyolefin-based membrane, wherein the crosslinking network of the polyamide layer contains an amino-polyethylene glycol-carboxyl transition metal salt.

[0007] The amino group in the amino-polyethylene glycol-carboxyl transition metal salt participates in the cross-linking reaction of the polyamide layer. Therefore, the amino-polyethylene glycol-carboxyl transition metal salt can be fixed in the composite reverse osmosis membrane material. The transition metal ions in the amino-polyethylene glycol-carboxyl transition metal salt can undergo coordination reactions with sulfur-containing and nitrogen-containing odor molecules, thereby fixing the odor molecules on the amino-polyethylene glycol-carboxyl transition metal salt and completing the adsorption of sulfur-containing and nitrogen-containing odor molecules.

[0008] The coordination number of transition metal ions determines the number of small odor molecules they adsorb. Therefore, it is preferable to select transition metals with a high coordination number with small odor molecules to improve adsorption efficiency and the service life of composite reverse osmosis membrane materials. In addition, considering the production cost, it is preferable to select low-priced transition metals.

[0009] Optionally, the amino-polyethylene glycol-carboxyl transition metal salt is selected from at least one of the amino-polyethylene glycol-carboxyl zinc salt, the amino-polyethylene glycol-carboxyl iron salt, and the amino-polyethylene glycol-carboxyl copper salt.

[0010] Zinc, iron, and copper are three transition metals that can meet the requirements of efficient adsorption and cost savings, and these three transition metals are also highly safe.

[0011] Optionally, the amino-polyethylene glycol-carboxyl transition metal salt is selected from the amino-polyethylene glycol-carboxyl zinc salt.

[0012] Zinc ions have a maximum coordination number of 6, so they can remove up to 6 odor molecules through coordination reactions, exhibiting highly efficient adsorption. The polyamide layer obtained using this amino-polyethylene glycol-carboxyl transition metal salt has the best desalination rate and odor removal effect.

[0013] Optionally, the amino-polyethylene glycol-carboxyl transition metal salt is obtained by reacting amino-polyethylene glycol-carboxyl with a transition metal salt.

[0014] Optionally, the degree of polymerization of the polyethylene glycol segment in the amino-polyethylene glycol-carboxyl transition metal salt is 2-25.

[0015] In amino-polyethylene glycol-carboxyl transition metal salts, a degree of polymerization (DOP) of polyethylene glycol between 2 and 25 ensures effective adsorption of small odor molecules without affecting the desalination rate of the reverse osmosis membrane. If the DOP is greater than 25, the excessive molecular weight of the polyethylene glycol will hinder the formation of the desalination layer, reducing the desalination rate. Conversely, if the DOP is too low, it may lead to end-capping with trimesoyl pyromellitic chloride, reducing the reaction between m-phenylenediamine and trimesoyl pyromellitic chloride, resulting in a lower degree of crosslinking in the polyamide layer. This, in turn, reduces the desalination rate of the membrane material and diminishes the desalination effect.

[0016] Optionally, the degree of polymerization of the polyethylene glycol segment in the amino-polyethylene glycol-carboxyl transition metal salt is 5-12.

[0017] Preferably, the degree of polymerization of the polyethylene glycol segment in the amino-polyethylene glycol-carboxyl transition metal salt is 10.

[0018] Optionally, the polyolefin-based film has a thickness of 10-60 μm and a porosity of 30-50%.

[0019] For example, the thickness of the polyolefin-based film can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, or any thickness between these values.

[0020] For example, the porosity of the polyolefin-based membrane can be 30%, 35%, 40%, 45%, 50%, or any porosity between these values.

[0021] Optionally, the polyolefin-based film is selected from polyethylene-based film, polypropylene-based film, and polyethylene / propylene composite film, preferably polyethylene-based film.

[0022] According to another aspect of this application, a method for preparing the composite reverse osmosis membrane material described in any of the above claims is provided, comprising the following steps:

[0023] (1) Coating or impregnating a polyolefin-based film with a solution containing an amine monomer and an amino-polyethylene glycol-carboxyl transition metal salt, wherein the amine monomer is a cyclic monomer containing at least two amino groups;

[0024] (2) The polyolefin-based membrane coated or impregnated in step (1) is subjected to an interfacial reaction with a solution containing trimesoyl chloride to form a polyamide layer, and the composite reverse osmosis membrane material is obtained after drying.

[0025] In the formation of the aforementioned polyamide layer, amine monomers and trimesoyl chloride react to form a cross-linked network. The terminal carboxyl groups of the amino-polyethylene glycol-carboxyl transition metal salt coordinate and complex with transition metal ions. The terminal amino groups react with trimesoyl chloride, resulting in chemically linked amino-polyethylene glycol-carboxyl transition metal salts within the cross-linked network of the polyamide layer. This improves the stability and uniform dispersion of the amino-polyethylene glycol-carboxyl transition metal salt in the polyamide layer. Odor-causing small molecules undergo coordination reactions with the transition metal ions of the amino-polyethylene glycol-carboxyl transition metal salt in the composite reverse osmosis membrane through nitrogen (N) and sulfur (S) atoms, forming stable complexes. This coordination chemical adsorption prevents sulfur- and nitrogen-containing odor molecules from releasing into the water, reducing the odor of pure water and improving the taste of drinking water.

[0026] One of the monomers forming the polyamide layer is pyromellitic trichloroethylene, whose structure can improve the rigidity of the polyamide layer, thereby playing a stabilizing and supporting role, reducing the deformation of the polyamide layer, and extending the service life of the composite reverse osmosis membrane material.

[0027] Optionally, the amine monomer is a cycloalkane monomer containing at least two amino groups or an aromatic monomer containing at least two amino groups.

[0028] The two amine monomers mentioned above contain benzene rings or aliphatic rings. As another monomer for the formation of the polyamide layer, they can cooperate with pyromellitic trimethylol chloride to further improve the rigidity and support of the polyamide layer, thereby increasing the strength and service life of the composite reverse osmosis membrane material.

[0029] Preferably, the aromatic monomer containing at least two amino groups is selected from at least one of m-phenylenediamine, o-phenylenediamine, and p-phenylenediamine; the cycloalkane monomer containing at least two amino groups is selected from at least one of piperazine and N-aminoethylpiperazine.

[0030] Preferably, the amine monomer is an aromatic monomer containing at least two amino groups.

[0031] More preferably, the amine monomer is m-phenylenediamine.

[0032] Optionally, in the solution containing amine monomers and amino-polyethylene glycol-carboxyl transition metal salts, the concentration of amine monomers is 1wt%-5wt%, the concentration of amino-polyethylene glycol-carboxyl transition metal salts is 0.2wt%-1.1wt%, the concentration of surfactants is 0.02wt%-0.2wt%, the remainder is water, and the pH is 9-11.

[0033] The pH of the solution is 9-11, which is beneficial to improving the reaction efficiency of the polyamide layer. The surfactant added to the solution can promote the wetting of the solution on the polyolefin-based film, thereby improving the formation of the polyamide layer. However, if the amount of surfactant added is too high, it is easy to form micelles, reduce the degree of crosslinking of the polyamide layer, and thus reduce the desalination rate.

[0034] Optionally, the surfactant is selected from at least one of sodium dodecylbenzenesulfonate, Tween 80, sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and hexadecyltrimethyl-p-toluenesulfonate.

[0035] Optionally, the concentration of pyromellitic chloride in the solution containing pyromellitic chloride is 0.1-0.5 wt%.

[0036] Preferably, the concentration of pyromellitic chloride in the solution containing pyromellitic chloride is 0.3 wt%.

[0037] Optionally, the interface reaction time in step (2) is 0.5-1 min.

[0038] Optionally, the interfacial reaction temperature in step (2) is room temperature.

[0039] Preferably, the interfacial reaction temperature in step (2) is 15-35℃.

[0040] Optionally, a hydrophilic treatment is required before coating or impregnating the polyolefin-based film with a solution containing amine monomers and amino-polyethylene glycol-carboxyl transition metal salts.

[0041] Hydrophilic treatment can improve the wetting and spreading of the solution on the polyolefin-based film, which is beneficial to improve the crosslinking degree and uniformity of the polyamide layer, thereby improving the desalination and adsorption effect of the polyamide layer.

[0042] Optionally, the hydrophilic treatment is an oxygen plasma treatment.

[0043] Optionally, the oxygen plasma treatment has a power of 10-30W and a treatment time of 5-50s.

[0044] According to another aspect of this application, the application of the composite reverse osmosis membrane material described in any one of the preceding claims or the composite reverse osmosis membrane material prepared by the preparation method described in any one of the preceding claims in a water purification device is provided.

[0045] The beneficial effects of this application include, but are not limited to:

[0046] 1. According to the composite reverse osmosis membrane material of this application, the transition metal ions in the amino-polyethylene glycol-carboxyl transition metal salt undergo a coordination reaction with the nitrogen (N) and sulfur (S) atoms of odor molecules to form a stable complex, thereby preventing sulfur- and nitrogen-containing odor molecules from being released into the water, reducing the odor of pure water and improving its taste.

[0047] 2. According to the composite reverse osmosis membrane material of this application, the amino-polyethylene glycol-carboxyl transition metal salt is introduced into the polyamide layer through chemical bonds, which can improve the stability of the amino-polyethylene glycol-carboxyl transition metal salt and prevent it from being lost during the water purification process. At the same time, it also improves the uniformity of its dispersion in the polyamide layer, so as to uniformly achieve the adsorption and retention of odor molecules and further improve the water quality.

[0048] 3. The composite reverse osmosis membrane material according to this application uses a polyolefin-based membrane as the substrate, which can reduce the thickness of the composite reverse osmosis membrane material. Compared with traditional non-woven fabric and polysulfone layer membranes, it can reduce the breeding sites of microorganisms and bacteria and their metabolic products, thereby improving water quality.

[0049] 4. The water purifier made using the composite reverse osmosis membrane material of this application can effectively reduce the odor of the water caused by bacterial growth, improve the taste of drinking water, and eliminate the need for a post-activated carbon filter, thus saving on the manufacturing and usage costs of the water purifier. Attached Figure Description

[0050] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0051] Figure 1 This is the reaction equation for the interfacial reaction that forms the polyamide layer in Embodiment 1 of this application. Detailed Implementation

[0052] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0053] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0054] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0055] In the following examples, the amino-polyethylene glycol-carboxyl transition metal salts are obtained by reacting amino-polyethylene glycol-carboxyl groups with transition metal salts. For example, amino-polyethylene glycol-carboxyl zinc salt is prepared by adding an equimolar amount of zinc chloride to amino-polyethylene glycol-carboxyl groups to adjust the pH to alkaline; amino-polyethylene glycol-carboxyl iron salt is prepared by adding an equimolar amount of ferric chloride to amino-polyethylene glycol-carboxyl groups to adjust the pH to alkaline; and amino-polyethylene glycol-carboxyl copper salt is prepared by adding an equimolar amount of copper chloride to amino-polyethylene glycol-carboxyl groups to adjust the pH to alkaline.

[0056] Example 1

[0057] This embodiment relates to a method for preparing a composite reverse osmosis membrane material, including the following steps:

[0058] (1) A polyethylene porous membrane with a thickness of 20 μm and a porosity of 48% was subjected to oxygen plasma treatment. The oxygen plasma treatment power was 20 W and the time was 25 s. The polyethylene porous membrane after oxygen plasma treatment was coated or impregnated with an aqueous solution containing amine monomers and amino-polyethylene glycol-carboxyl transition metal salt. The concentration of intermediate phenylenediamine in the aqueous solution was 3 wt%, the concentration of amino-polyethylene glycol 10-carboxylated zinc salt (polyethylene glycol degree of polymerization was 10) was 0.7 wt%, the concentration of sodium dodecylbenzenesulfonate (SDS) was 0.05 wt%, and the remainder was water. The pH was adjusted to 9-11.

[0059] (2) Pour a solution containing 0.3 wt% trimesoyl chloride into one side of the polyethylene porous membrane coated or impregnated in step (1) to carry out an interfacial reaction for 30 s to form a polyamide layer. The reaction equation for the interfacial reaction is shown in [reference needed]. Figure 1 After the reaction is complete, the material is dried at 80°C, washed with pure water, and dried again to obtain the composite reverse osmosis membrane material.

[0060] Examples 2-19 and Comparative Example 1 were set up in the same manner as Example 1, with specific differences shown in Table 1. In the table, amino-polyethylene glycol 10-carboxylated zinc salt represents a degree of polymerization of polyethylene glycol of 10, amino-polyethylene glycol 2-carboxylated zinc salt represents a degree of polymerization of polyethylene glycol of 2, and amino-polyethylene glycol 25-carboxylated zinc salt represents a degree of polymerization of polyethylene glycol of 25.

[0061] Table 1

[0062]

[0063]

[0064] Example 20

[0065] The difference between this embodiment and Example 1 is that amino-polyethylene glycol 10-carboxylated iron salt is used to replace amino-polyethylene glycol 10-carboxylated zinc salt in Example 1, while the rest are the same as in Example 1.

[0066] Example 21

[0067] The difference between this embodiment and Example 1 is that amino-polyethylene glycol 10-carboxylated copper salt is used instead of amino-polyethylene glycol 10-carboxylated zinc salt in Example 1, while the rest are the same as in Example 1.

[0068] Test case

[0069] The composite reverse osmosis membranes obtained in the above implementation and comparative examples were tested:

[0070] (1) Desalination rate test: Desalination rate = [(raw water concentration - pure water concentration after filtration) / raw water concentration] × 100%. The raw water concentration was 250 mg / L sodium chloride solution, the pressure was 0.41 MPa, and the temperature was 25℃.

[0071] (2) Sulfide and odor test: The above composite reverse osmosis membrane was rolled into a 600G flux reverse osmosis membrane filter element, and tap water and booster pump were connected to simulate the use of purifying 1800L of water. After the machine was shut down for 7 days, the machine was turned on again and the first cup of pure water was taken for spectrophotometry (HJ 1226—2021) to determine the sulfide concentration (detection limit 0.003mg / L), and the taste and odor of the water sample were identified.

[0072] The test results are shown in Table 2:

[0073] Table 2

[0074]

[0075]

[0076] According to the above data, the polyolefin-based membrane used in the composite reverse osmosis membrane material of this application has a smaller thickness compared to the traditional non-woven fabric and polysulfone layer base membrane, which can reduce the breeding sites of bacteria and the metabolic products. The amino-polyethylene glycol-carboxyl transition metal salt can adsorb small odor molecules, reduce odor and improve taste.

[0077] Compared with Example 1, the oxygen plasma treatment times in Examples 2-3 were 5s and 50s, respectively. Shortening the treatment time resulted in insufficient treatment time for the polyethylene film surface, insufficient hydrophilicity, and difficulty in spreading the aqueous solution. Extending the treatment time did not significantly improve the desalination rate and odor reduction, but it reduced the processing efficiency.

[0078] Compared to Example 1, in Examples 4-5, sodium dodecylbenzenesulfonate (SDS) as a surfactant can promote the wetting of the aqueous solution on the porous polyethylene membrane. Too low an SDS concentration is detrimental to the wetting and spreading of the aqueous solution, reducing the desalination rate of the polyamide layer; too high an SDS concentration easily forms micelles, reducing the crosslinking degree of the polyamide layer and also decreasing the desalination rate.

[0079] Compared with Example 1, in Examples 6-7, the concentration of amino-polyethylene glycol-carboxylated zinc salt with a degree of polymerization of 10 was reduced, resulting in limited odor removal; the concentration was increased, which would reduce the cross-linking degree of the desalination layer, leading to a decrease in the desalination rate of the reverse osmosis membrane.

[0080] Compared to Example 1, Examples 8-9 show amino-polyethylene glycol-carboxylated zinc salts with degrees of polymerization of 2 and 25, respectively. With a lower degree of polymerization of polyethylene glycol, the molecular chain of the amino-polyethylene glycol-carboxylated zinc salt is shorter, making it easier for the amino group of the amino-polyethylene glycol-carboxylated zinc salt to react with trimesoyl chloride for end-capping, resulting in a decrease in desalination rate. Conversely, with a higher degree of polymerization of polyethylene glycol, the molecular chain of the amino-polyethylene glycol-carboxylated zinc salt is too large, hindering the polymerization of trimesoyl chloride and m-phenylenediamine, also leading to a decrease in desalination rate.

[0081] Compared with Example 1, in Examples 10-11, the concentration of m-phenylenediamine was too low, resulting in a thin polyamide layer and a low desalination rate; the concentration of m-phenylenediamine was too high, resulting in a thick polyamide layer and increased costs.

[0082] Compared to Example 1, Example 12 shows that the increased thickness of the polyethylene porous membrane leads to a higher content of pores for bacterial growth, resulting in more bacteria and more metabolic products.

[0083] Compared with Examples 1, 6, and 7, Examples 13-14 show that the concentration of amino-polyethylene glycol-carboxylated zinc salt with a degree of polymerization of 10 is too low, and has almost no effect on adsorbing odors; while the concentration is too high, and the desalination rate of the composite reverse osmosis membrane material decreases too much.

[0084] Compared with Examples 8 and 9, the amino-polyethylene glycol-carboxylated zinc salts with degrees of polymerization of 2 and 25, respectively, in Examples 15-16, were insufficient in adsorbing odor molecules at excessively low concentrations.

[0085] Compared with Examples 1, 2, and 3, Example 17 has too short an oxygen plasma treatment time, insufficient hydrophilicity of the polyethylene film, and an inability to form a complete polyamide layer on its surface, resulting in a very low desalination rate.

[0086] Compared with Examples 1, 4, and 5, in Example 18, without SDS, the aqueous solution spreads unevenly, resulting in an uneven polyamide layer and a significant decrease in desalination rate.

[0087] Compared with Examples 1 and 12, Example 19 shows an increased thickness of the polyethylene porous membrane, which further increases bacterial growth and odor-causing substances, making it less effective at removing odors.

[0088] Examples 20-21 and Comparative Example 1, compared to Example 1, demonstrate that using other amino-polyethylene glycol-carboxyl transition metal salts can also achieve the adsorption of sulfur- and nitrogen-containing odor molecules, preventing these molecules from escaping into the water. This solves the technical problem of existing reverse osmosis water purifiers producing odors and foul smells after being left unused for several days or even longer, and eliminates the need for a post-activated carbon filter, saving costs. Without the polyamide layer formed by amino-polyethylene glycol-carboxyl transition metal salts, the adsorption of odor molecules cannot be achieved, and the problem of odors and foul smells in the purified water will still exist after the water purifier is left unused for several days.

[0089] When the m-phenylenediamine in Example 1 is replaced with o-phenylenediamine, p-phenylenediamine, piperazine, or N-aminoethylpiperazine, the monomers all contain benzene rings or cycloalkanes, which can provide support for the polyamide layer. The performance of the composite reverse osmosis membrane material prepared by these monomers is generally consistent with that of Example 1, and both can solve the technical problems solved by this application.

[0090] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A composite reverse osmosis membrane material, characterized in that, The composite reverse osmosis membrane material includes a polyolefin-based membrane and a polyamide layer formed on the polyolefin-based membrane, wherein the crosslinked network of the polyamide layer contains an amino-polyethylene glycol-carboxyl transition metal salt.

2. The composite reverse osmosis membrane material according to claim 1, characterized in that, The amino-polyethylene glycol-carboxyl transition metal salt is selected from at least one of the amino-polyethylene glycol-carboxyl zinc salt, the amino-polyethylene glycol-carboxyl iron salt, and the amino-polyethylene glycol-carboxyl copper salt.

3. The composite reverse osmosis membrane material according to claim 2, characterized in that, The amino-polyethylene glycol-carboxyl transition metal salt is selected from the amino-polyethylene glycol-carboxyl zinc salt.

4. The composite reverse osmosis membrane material according to claim 1, characterized in that, The degree of polymerization of the polyethylene glycol segment in the amino-polyethylene glycol-carboxyl transition metal salt is 2-25.

5. The composite reverse osmosis membrane material according to claim 4, characterized in that, The degree of polymerization of the polyethylene glycol segment in the amino-polyethylene glycol-carboxyl transition metal salt is 5-12.

6. The method for preparing the composite reverse osmosis membrane material according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Coating or impregnating a polyolefin-based film with a solution containing an amine monomer and an amino-polyethylene glycol-carboxyl transition metal salt, wherein the amine monomer is a cyclic monomer containing at least two amino groups; (2) The polyolefin-based membrane coated or impregnated in step (1) is subjected to an interfacial reaction with a solution containing trimesoyl chloride to form a polyamide layer, and the composite reverse osmosis membrane material is obtained after drying.

7. The method for preparing the composite reverse osmosis membrane material according to claim 6, characterized in that, The solution containing amine monomers and amino-polyethylene glycol-carboxyl transition metal salts has the following concentrations: amine monomers at 1 wt%-5 wt%, amino-polyethylene glycol-carboxyl transition metal salts at 0.2 wt%-1.1 wt%, surfactants at 0.02 wt%-0.2 wt%, the remainder being water, and pH 9-11.

8. The method for preparing the composite reverse osmosis membrane material according to claim 6, characterized in that, The concentration of pyromellitic chloride in the solution containing pyromellitic chloride is 0.1-0.5 wt%.

9. The method for preparing the composite reverse osmosis membrane material according to claim 6, characterized in that, The interface reaction time in step (2) is 0.5-1 min.

10. The application of the composite reverse osmosis membrane material according to any one of claims 1-5 or the composite reverse osmosis membrane material according to any one of claims 6-9 in a water purification device.

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