Polymer reverse osmosis membrane, and preparation method therefor and use thereof

Abstract

A polymer reverse osmosis membrane, and a preparation method therefor and the use thereof. The polymer reverse osmosis membrane comprises a polyolefin base membrane (1), wherein the surface of the polyolefin base membrane is sequentially provided with a polymer fiber support layer (2), a polymer fiber hydrophilic layer (3) and a compact functional layer (4), and there is an overlapping region (5) in the polymer fiber support layer (2) and the polymer fiber hydrophilic layer (3) along the direction of thickness of the polymer reverse osmosis membrane. By arranging the polymer fiber support layer (2) and the polymer fiber hydrophilic layer (3) between the polyolefin base membrane (1) and the compact functional layer (4), the resulting polymer reverse osmosis membrane has small water mass transfer resistance and thus a high flux; moreover, the polymer reverse osmosis membrane also has good solvent resistance and pressure resistance, and can be used within a wide range of ambient temperatures, thereby ensuring long-term stable operation of an assembly containing same.

Description

A polymer reverse osmosis membrane and its preparation method and application Technical Field

[0001] The present application relates to the technical field of osmotic membranes, for example, a polymer reverse osmosis membrane and its preparation method and application. Background Art

[0002] Reverse osmosis membrane is an artificial semipermeable membrane with certain characteristics made by simulating biological semipermeable membrane. It is the core component of reverse osmosis technology. The principle of reverse osmosis technology is to separate substances and water under the action of an osmotic pressure higher than that of the solution, based on the fact that other substances cannot pass through the semipermeable membrane. It is widely used in many fields such as high-purity water preparation in the electronics industry, medical water preparation, seawater desalination, brackish water desalination, and sewage recycling.

[0003] At present, the mainstream reverse osmosis membranes on the market are still mainly non-woven reverse osmosis membranes; however, due to the reasons of the non-woven material itself, the operating environment temperature of non-woven reverse osmosis membranes can only be below 50°C, and their solvent resistance is poor, and their long-term operating stability is weak; based on this, some researchers use polyolefin (such as polyethylene) microporous membranes as the substrate, and conduct interfacial condensation reaction on its surface to form a dense functional layer, thereby preparing a low-cost, simpler structure and certain permeability polymer reverse osmosis membrane.

[0004] However, polyolefin microporous membranes are generally thin and soft, not resistant to high pressure, and have very limited usage scenarios. They are prone to deformation under high pressure, blocking the water production flow channel, thereby affecting the flux of the water treatment component. Compared with traditional reverse osmosis membranes, membrane bags of the same length have greater concentration difference polarization, affecting the life of the component; and in the component manufacturing process, polyolefin water treatment membranes are prone to static electricity. They are soft and thin, making it inconvenient to fold the membrane in half, and wrinkles are easily generated when they are picked up, affecting the efficiency of component manufacturing and causing a decrease in the yield rate.

[0005] Summary of the Invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] The present application provides a polymer reverse osmosis membrane, a preparation method and application thereof. By arranging a polymer fiber support layer and a polymer fiber hydrophilic layer between a polyolefin base membrane and a dense functional layer, the obtained polymer reverse osmosis membrane has the advantages of thin thickness, strong solvent resistance and strong pressure resistance while maintaining a high desalination rate. This can ensure that the components containing it have a high flux, can adapt to more stringent environments such as high temperature, high pressure, and organic solvent-containing wastewater treatment, and can operate stably for a long time.

[0008] In a first aspect, the present application provides a polymer reverse osmosis membrane, comprising a polyolefin-based membrane, wherein a polymer fiber support layer, a polymer fiber hydrophilic layer, and a dense functional layer are sequentially provided on the surface of the polyolefin-based membrane;

[0009] The polymer fiber support layer and the polymer fiber hydrophilic layer have an overlapping area in the thickness direction of the polymer reverse osmosis membrane.

[0010] First, the polymer reverse osmosis membrane provided in the present application includes a polyolefin-based membrane, the surface of which is sequentially provided with a polymer fiber support layer, a polymer fiber hydrophilic layer, and a dense functional layer; wherein the polyolefin-based membrane serves as a substrate and has a certain thickness, porosity, pore size, and mechanical strength, which can reduce water mass transfer resistance, improve the flux of the reverse osmosis membrane, and have good solvent resistance;

[0011] Secondly, a polymer fiber support layer is preferentially provided on the surface of the polyolefin-based membrane. The polymer fiber support layer has excellent chemical resistance and mechanical strength, thereby improving the solvent resistance, pressure resistance and rigidity of the entire polymer reverse osmosis membrane, facilitating subsequent component processing and manufacturing, and improving the component yield rate;

[0012] Thirdly, a polymer fiber hydrophilic layer is provided on the surface of the polymer fiber support layer. The polymer fiber hydrophilic layer has moderate hydrophilicity. On the basis of maintaining the high porosity of the polymer reverse osmosis membrane, the pore size of the polymer reverse osmosis membrane is further reduced, providing favorable conditions for the subsequent preparation of a dense functional layer by interfacial polymerization, and ensuring the integrity of the dense functional layer, thereby maintaining a high desalination rate.

[0013] At the same time, the present application also stipulates that the polymer fiber support layer and the polymer fiber hydrophilic layer have an overlapping area in the thickness direction of the polymer reverse osmosis membrane. In the overlapping area, the fibers of the polymer fiber support layer and the fibers of the polymer fiber hydrophilic layer are interwoven together. As a result, the polymer fiber support layer and the polymer fiber hydrophilic layer can be tightly combined through physical embedding and chemical action (intermolecular force) at the contact surface between the fibers without obvious stratification, thereby ensuring long-term stable operation without stratification, and also helping to form an integrated asymmetric pore structure, shortening the water passage path, and improving the flux of the component;

[0014] Finally, a dense functional layer is provided on the polymer fiber hydrophilic layer, which can ensure that the entire polymer reverse osmosis membrane has excellent water treatment function;

[0015] In summary, the present application provides a polymer reverse osmosis membrane that has a smaller water mass transfer resistance and thus has a higher flux by adopting the above-mentioned four-layer structure. At the same time, it also has excellent solvent resistance and pressure resistance, thereby ensuring that the water treatment components containing it can adapt to more stringent application scenarios and operate stably for a long time.

[0016] It should be noted that the "overlapping area" mentioned in the present application refers to the partial area of ​​the polymer fiber support layer in the thickness direction and the partial area of ​​the polymer fiber hydrophilic layer in the thickness direction overlapping to form a whole that is difficult to separate, that is, there is no situation where all areas of the polymer fiber support layer in the thickness direction completely overlap with the polymer fiber hydrophilic layer (the polymer fiber support layer is completely embedded in the polymer fiber hydrophilic layer), nor is there a situation where all areas of the polymer fiber hydrophilic layer in the thickness direction completely overlap with the polymer fiber support layer (the polymer fiber hydrophilic layer is completely embedded in the polymer fiber support layer).

[0017] In one embodiment, the total thickness of the polyolefin base membrane, the polymer fiber support layer and the polymer fiber hydrophilic layer is not higher than 40 μm, for example, 38 μm, 36 μm, 34 μm, 32 μm, 30 μm, 28 μm, 26 μm, 24 μm, 22 μm or 20 μm.

[0018] It should be noted that the above-mentioned "total thickness of the polyolefin base film, the polymer fiber support layer and the polymer fiber hydrophilic layer" refers to the actual measured thickness of the three. Since there is an overlapping area between the polymer fiber support layer and the polymer fiber hydrophilic layer, the total thickness of the three is not a simple accumulation of the thicknesses of the three, but the repeated accumulation thickness of the overlapping area should be eliminated. For example, the polyolefin base film is set to 5μm, the thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer are 10μm and 5μm respectively, and the thickness of the overlapping area is set to 2μm. Then the total thickness of the polyolefin base film, the polymer fiber support layer and the polymer fiber hydrophilic layer is: 5+10+5-2=18μm.

[0019] In one embodiment, the average pore size of the polyolefin-based membrane is 100-250 nm. For example, the average pore size of the polyolefin-based membrane may be 120 nm, 140 nm, 160 nm, 180 nm, 200 nm, 220 nm, 240 nm, or a range consisting of any two thereof.

[0020] In one embodiment, the thickness of the polyolefin-based film is 7-10 μm. For example, the thickness of the polyolefin-based film may be 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, or a range consisting of any two thereof.

[0021] In one embodiment, the porosity of the polyolefin-based membrane is 40-80%. For example, the porosity of the polyolefin-based membrane may be 45%, 55%, 60%, 65%, 70%, 75% or any two thereof.

[0022] As an optional technical solution of the present application, further limiting the thickness, average pore size and porosity of the polyolefin-based membrane can enable the obtained polymer reverse osmosis membrane to have a lower water mass transfer resistance on the basis of higher selectivity, and thus have a higher flux.

[0023] In one embodiment, the material of the polyolefin-based film includes any one or a combination of at least two of homopolymers or copolymers of ethylene, propylene, 1-butene, pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene.

[0024] In one embodiment, the surface of the polyolefin-based film contains polar groups.

[0025] In one embodiment, the polar group includes any one of a hydroxyl group and a carboxyl group.

[0026] In one embodiment, the polyolefin-based film is a polyolefin-based film that has been subjected to a hydrophilic modification treatment.

[0027] It should be noted that the method for hydrophilic modification of the polyolefin base membrane can be any method that makes the polyolefin base membrane have hydrophilic polarity, as long as the surface of the treated polyolefin base membrane has hydrophilic polar groups, including but not limited to strong acid treatment, radiation grafting treatment, plasma treatment, etc., or physical modification methods, such as coating hydrophilic compounds, etc.

[0028] In one embodiment, the solvent resistance of the material of the polymer fiber support layer is above 98%, for example, 98.5%, 99%, 99.5% or a range consisting of any two thereof; the above-mentioned solvent resistance evaluation method is expressed by the mass residual rate before and after solvent immersion. Specifically, the test method of the mass residual rate before and after solvent immersion includes: placing 1g (denoted as M1) of the sample in 50mL of a 1M organic solution of hydrochloric acid or sodium hydroxide (the solvent includes tetrahydrofuran, toluene or ethanol, etc.), at 25°C, completely soaking for 7 days, taking out the sample, washing it with pure water and soaking it for 24 hours, and weighing the sample mass M2 after vacuum drying. The mass residual rate (i.e., solvent resistance) is calculated by the following formula: mass residual rate = M2 / M1×100%.

[0029] In one embodiment, the polymer fiber support layer includes any one of fluorine-containing fibers or polyimide fibers.

[0030] In one embodiment, the fluorine-containing fiber includes any one of polyvinylidene fluoride fiber, polyvinylidene fluoride hexafluoropropylene fiber, polyvinylidene fluoride-tetrafluoroethylene fiber or polyvinylidene fluoride-tetrafluorochloroethylene fiber, or a combination of at least two thereof.

[0031] In one embodiment, the thickness of the polymer fiber support layer is 10 to 20 μm. For example, the thickness of the polymer fiber support layer can be 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or a range consisting of any two thereof.

[0032] In one embodiment, the average pore size of the polymer fiber support layer is 100-500 nm. For example, the average pore size of the polymer fiber support layer can be 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, or a range consisting of any two thereof.

[0033] As an optional technical solution of the present application, further limiting the thickness and pore size of the polymer fiber support layer can ensure that the polymer reverse osmosis membrane has higher strength, better solvent resistance, high temperature resistance and high pressure resistance, while also having lower water mass transfer resistance, thereby having a higher flux.

[0034] In one embodiment, the water contact angle of the material of the polymer fiber hydrophilic layer is 40 to 85°, for example, the water contact angle can be 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80° or a range consisting of any two thereof; if the water contact angle is too small, the excessive hydrophilicity of the polymer fiber hydrophilic layer will easily cause the aqueous phase solution to penetrate into the pore size of the polyolefin-based membrane during the subsequent interfacial polymerization, resulting in a low desalination rate; if the water contact angle is too large, the hydrophilicity of the polymer fiber hydrophilic layer is weak, which will easily cause the aqueous phase solution to be unevenly distributed on its surface during the subsequent interfacial polymerization, forming a defective polyamide layer, and reducing the desalination rate.

[0035] In this application, the above-mentioned water contact angle test method is to use the DSA25E contact angle instrument of the German Kruss company for testing. The sample is flatly fixed on the test table, the injection volume is 2.5μL, the injection rate is 300μL / min, and the high-speed camera is used to take pictures more than 3 times. The average value is the test result.

[0036] In one embodiment, the polymer fiber hydrophilic layer includes any one of polyacrylonitrile fiber, polysulfone fiber, polyethersulfone fiber or sulfonated polysulfone fiber, or a combination of at least two thereof; the above fibers are all materials with moderate hydrophilicity, which can provide more favorable conditions for subsequent interfacial polymerization to form a dense functional layer.

[0037] In one embodiment, the thickness of the polymer fiber hydrophilic layer is 3 to 7 μm. For example, the thickness of the polymer fiber hydrophilic layer can be 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm or a range consisting of any two of them.

[0038] In one embodiment, the average pore size of the polymer fiber hydrophilic layer is 20-50 nm. For example, the average pore size may be 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or a range consisting of any two thereof.

[0039] Similarly, the present application further limits the thickness and average pore size of the polymer fiber hydrophilic layer, which can ensure that the polymer reverse osmosis membrane has a lower water mass transfer resistance and thus a higher flux; and since the optimal pore size for polymerization is tens of nanometers, the average pore size of the polymer fiber hydrophilic layer is limited to 20 to 50 nm, which can provide more favorable conditions for the subsequent interfacial polymerization to form a dense functional layer. If its average pore size is too large, it will easily cause the aqueous phase solution to penetrate into the pore size of the polyolefin-based membrane during the interfacial polymerization process, resulting in a low desalination rate, and if its average pore size is too small, it will result in a low flux.

[0040] In one embodiment, the thickness of the overlapping area is not higher than 30% of the total thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer. For example, the thickness of the overlapping area can be 28%, 26%, 24%, 22%, 20% or a range consisting of any two of them.

[0041] It should be noted that the above-mentioned "total thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer" refers to the actual total thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer combined together in the multi-layer composite reverse osmosis membrane, that is, it is not a direct and simple accumulation of the thickness of each layer, but the repeated accumulation thickness of the overlapping area should be eliminated. For example, the thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer are set to 10μm and 5μm respectively, and the thickness of the overlapping area is set to 2μm, then the thickness of the overlapping area accounts for 2 / (10+5-2)×100%=15.38% of the total thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer.

[0042] In one embodiment, the thickness of the dense functional layer is 100 to 500 nm. For example, the thickness of the dense functional layer may be 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm or 450 nm, or a range consisting of any two thereof.

[0043] In one embodiment, the dense functional layer is a polyamide layer.

[0044] In one embodiment, the dense functional layer is formed by interfacial polymerization.

[0045] In a second aspect, the present application provides a method for preparing the polymer reverse osmosis membrane as described in the first aspect, the method comprising: forming a polymer fiber support layer, a polymer fiber hydrophilic layer, and a dense functional layer on the surface of a polyolefin-based membrane to obtain the polymer reverse osmosis membrane. In one embodiment, the method comprises the following steps:

[0046] (1) forming a polymer fiber support layer and a polymer fiber hydrophilic layer on the surface of a polyolefin base film by electrospinning;

[0047] (2) forming a dense functional layer on the surface of the polymer fiber hydrophilic layer by interfacial polymerization to obtain the polymer reverse osmosis membrane.

[0048] In one embodiment, the polyolefin-based membrane in step (1) is subjected to a hydrophilic modification treatment.

[0049] In one embodiment, the hydrophilic modification treatment method includes any one or a combination of at least two of strong acid treatment, radiation grafting treatment, coating with a hydrophilic compound, or plasma treatment.

[0050] In one embodiment, the method of simultaneously forming the polymer fiber support layer and the polymer fiber hydrophilic layer in step (1) specifically comprises the following steps:

[0051] (1A) providing a solution containing a polymer A forming the polymer fiber support layer and a solution containing a polymer B forming the polymer fiber hydrophilic layer;

[0052] (1B) Electrospinning is performed simultaneously using the solution containing polymer A and the solution containing polymer B in step (1A) as spinning solutions to form the polymer fiber support layer and the polymer fiber hydrophilic layer.

[0053] In the optional preparation method provided in the present application, the polymer fiber support layer and the polymer fiber hydrophilic layer are both formed by simultaneous electrospinning with two needles, and a needle containing a solution containing polymer A and a needle containing a solution containing polymer B are successively arranged along the movement direction of the polyolefin base membrane spinning process, and the two needles are limited to move back and forth in a horizontal direction for electrospinning. During the preparation process, the fiber thickness and pore size can be controlled by reasonably setting the electrospinning parameters.

[0054] In one embodiment, in step (1A), the mass percentage of polymer A in the solution containing polymer A is 10-20%. For example, the mass percentage of polymer A can be 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or a range consisting of any two thereof.

[0055] In one embodiment, in step (1A), the mass percentage of polymer B in the solution containing polymer B is 10-20%. For example, the mass percentage of polymer B can be 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or a range consisting of any two thereof.

[0056] In one embodiment, in the step (1A), the polymer A is at least one of a fluorine-containing resin or a polyimide.

[0057] In one embodiment, in step (1A), the polymer B is at least one of polyacrylonitrile, polysulfone, polyethersulfone or sulfonated polysulfone, or a combination of at least two thereof.

[0058] In one embodiment, in step (1A), the solvents in the solution containing polymer A and the solution containing polymer B each independently include any one or a combination of at least two of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetone or hexafluoroisopropanol.

[0059] In one embodiment, in step (1A), the solution containing polymer A and the solution containing polymer B further comprise tetrabutylammonium chloride.

[0060] As an optional technical solution of the present application, tetrabutylammonium chloride is further added to the solution containing polymers A and B forming the polymer fiber support layer and the hydrophilic layer.

[0061] In one embodiment, the mass percentage of tetrabutylammonium chloride in the solution containing polymer A is 0.25-0.8%, for example, 0.26%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8% or any two thereof.

[0062] In one embodiment, the mass percentage of tetrabutylammonium chloride in the solution containing polymer A is 0.26-0.7%.

[0063] In one embodiment, the mass percentage of tetrabutylammonium chloride in the solution containing polymer B is 0.17-0.23%, for example, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23% or any two thereof.

[0064] In one embodiment, the mass percentage of tetrabutylammonium chloride in the solution containing polymer B is 0.17-0.23%.

[0065] In the present application, by adding tetrabutylammonium chloride and adjusting the ratio, the pore size distribution of the polymer fiber support layer and the polymer fiber hydrophilic layer can be better controlled. Under the premise of maintaining high porosity, fiber layers with different pore size distributions are prepared. The larger pore size of the support layer is conducive to the transmission of water molecules and maintains high flux. At the same time, the pore size of the polymer fiber hydrophilic layer is limited to a smaller size, which is more conducive to the occurrence of interfacial polymerization, so that the prepared dense functional layer has better integrity.

[0066] In one embodiment, in step (1B), the distance between the two needles during the electrospinning process is 1 to 10 cm, for example, 2 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm or a range consisting of any two thereof; by adjusting the distance between the two needles in electrospinning, the proportion of the overlapping area of ​​the polymer fiber support layer and the polymer fiber hydrophilic layer can be controlled.

[0067] In one embodiment, the propulsion speed of the spinning needle of the solution containing polymer A is 0.009-0.020 mL / min, for example, 0.011 mL / min, 0.013 mL / min, 0.015 mL / min, 0.017 mL / min, 0.019 mL / min or a range consisting of any two thereof.

[0068] In one embodiment, the propulsion speed of the spinning needle of the solution containing polymer B is 0.001 to 0.007 mL / min, for example, 0.002 mL / min, 0.004 mL / min, 0.006 mL / min, or any combination thereof.

[0069] In one embodiment, after the electrospinning in step (1B) is completed, the step further includes a drying step in an oven at 80-130°C (for example, the temperature may be 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C or a range of any two thereof).

[0070] It should be noted that, as long as the dense functional layer satisfies the above-mentioned various characteristics, the raw materials and production methods can be freely selected according to the purpose.

[0071] In one embodiment, the dense functional layer is prepared by interfacial polymerization.

[0072] In one embodiment, the raw materials for preparing the dense functional layer include water-phase monomers and oil-phase monomers.

[0073] In one embodiment, the aqueous phase monomer includes a polyvalent aromatic amine compound and / or a polyvalent aliphatic amine compound.

[0074] In one embodiment, the polyvalent aromatic amine compound includes any one or a combination of at least two of m-phenylenediamine, o-phenylenediamine, m-phenylenediamine-5-sulfonic acid, N,N-dimethylphenylenediamine or m-phenylenediamine.

[0075] In one embodiment, the polyvalent fatty amine compound includes any one of polyethyleneimine, 1,4-cyclohexanediamine, or polyaminopolyethylene oxide, or a combination of at least two thereof.

[0076] In one embodiment, the oil phase monomer comprises a polyacyl chloride.

[0077] In one embodiment, the polyacid chloride includes any one of trimesoyl chloride, 1,3,5-cyclohexanetricarbonyl chloride, 5-isocyanate-isophthaloyl chloride, biphenyltricarbonyl chloride, o- / m- / terephthaloyl chloride or 5-oxocarbonyl chloride-isophthaloyl chloride or a combination of at least two thereof.

[0078] In one embodiment, the specific method of forming the polyamide functional layer comprises the following steps:

[0079] (B1) separately providing an aqueous phase solution containing aqueous phase monomers and an oil phase solution containing oil phase monomers;

[0080] (B2) first coating the surface of the hydrophilic layer of the polymer fiber with an oil phase solution and then with an aqueous phase solution, or first coating the surface with an aqueous phase solution and then with an oil phase solution, and finally performing heat treatment and post-treatment to form the polyamide functional layer.

[0081] In one embodiment, in step (B1), the mass percentage of the aqueous phase monomer in the aqueous phase solution is 1-10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or a range consisting of any two thereof.

[0082] In one embodiment, in step (B1), the mass percentage of the oil phase monomer in the oil phase solution is 0.1-1%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or a range consisting of any two thereof.

[0083] In one embodiment, in step (B2), the heat treatment temperature is 50-100°C, for example, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or any two thereof.

[0084] In one embodiment, in step (B2), the heat treatment time is 5 to 30 min, for example, 7 min, 9 min, 11 min, 13 min, 15 min, 17 min, 19 min, 23 min, 25 min, 28 min or a range consisting of any two thereof.

[0085] In one embodiment, in step (B2), the post-treatment includes: any one or a combination of at least two of water washing, mixed solvent swelling, acid washing, oxidation treatment or moisturizing treatment.

[0086] In a third aspect, the present application provides a use of the polymer reverse osmosis membrane as described in the first aspect or the polymer reverse osmosis membrane prepared by the preparation method of the polymer reverse osmosis membrane as described in the second aspect in a water treatment device.

[0087] Compared with the related art, this application has the following beneficial effects:

[0088] The polymer reverse osmosis membrane provided by the present application includes a polyolefin base membrane, on the surface of which a polymer fiber support layer, a polymer fiber hydrophilic layer and a dense functional layer are sequentially arranged, and the polymer fiber support layer and the polymer fiber hydrophilic layer have an overlapping area in the thickness direction of the polymer reverse osmosis membrane; by arranging the polymer fiber support layer and the polymer fiber hydrophilic layer between the polyolefin base membrane layer and the dense functional layer, the water mass transfer resistance of the obtained polymer reverse osmosis membrane is small, and thus has a higher flux, and at the same time has excellent solvent resistance and pressure resistance, and has a wide range of operating environment temperature requirements, thereby ensuring that the components containing it can operate stably for a long time.

[0089] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0091] FIG1 is a schematic diagram of the cross-sectional structure of a polymer reverse osmosis membrane provided by the present application;

[0092] FIG2 is a schematic side view of the structure of an electrospinning device;

[0093] FIG3 is a schematic diagram of the top view of the electrospinning device;

[0094] Among them, 1-polyolefin base film, 2-polymer fiber support layer, 3-polymer fiber hydrophilic layer, 4-dense functional layer, 5-overlapping area, 6-first spinning needle, 2-second spinning needle. DETAILED DESCRIPTION

[0095] The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0096] Some of the raw material information involved in the specific implementation of this application is as follows:

[0097] (1) PE base film: from Shenzhen Xingyuan Material Technology Co., Ltd.;

[0098] (2) Polyimide: Torlon 4000T from Solvay, USA;

[0099] (3) Polyvinylidene fluoride: from Shanghai Sanaifu New Material Technology Co., Ltd., FR904;

[0100] (4) Polyvinylidene fluoride hexapropylene: from Solvay, USA, 21216;

[0101] (5) Polysulfone resin: from Solvay, USA, Udel P-1700 LCD;

[0102] (6) Polyethersulfone resin: from BASF, E6020P;

[0103] (7) Polyacrylonitrile resin: from Shanghai MacLean Biochemical Technology Co., Ltd., Mw = 150,000.

[0104] Example 1

[0105] A polymer reverse osmosis membrane, the cross-sectional structure of which is shown in FIG1 , comprises a polyolefin base membrane 1, a polymer fiber support layer 2, a polymer fiber hydrophilic layer 3, and a dense functional layer 4 arranged in sequence, wherein the polymer fiber support layer 2 and the polymer fiber hydrophilic layer 3 have an overlapping region 5 in the thickness direction of the polymer reverse osmosis membrane;

[0106] The total thickness of the polyolefin base film 1, the polymer fiber support layer 2 and the polymer fiber hydrophilic layer 3 is 25 μm.

[0107] The polyolefin base film 1 is a hydrophilic treated PE base film with a thickness of 8 μm, an average pore size of 200 nm, and a porosity of 70%;

[0108] The material of the polymer fiber support layer 2 is polyimide fiber with a thickness of 15 μm and an average pore size of 250 nm;

[0109] The material of the polymer fiber hydrophilic layer 3 is polysulfone fiber (water contact angle is 73°), with a thickness of 7 μm and an average pore size of 30 nm;

[0110] The thickness of the overlapping region 5 is 5 μm, and the overlapping region 5 accounts for 29.4% of the total thickness of the polymer fiber support layer 2 and the polymer fiber hydrophilic layer 3;

[0111] The material of the dense functional layer 4 is polyamide, with a thickness of 200 nm;

[0112] The method for preparing the polymer reverse osmosis membrane provided in this embodiment comprises the following steps:

[0113] (1) Plasma treatment of the PE base film (3 kW for 15 s) to obtain a hydrophilic PE base film;

[0114] Dissolving polyimide and tetrabutylammonium chloride in DMF to obtain a polyimide mixed solution having a mass percentage content of 15% of polyimide and a mass percentage content of 0.42% of tetrabutylammonium chloride;

[0115] Dissolving polysulfone resin and tetrabutylammonium chloride in DMF to obtain a polysulfone mixed solution having a polysulfone resin content of 15% by weight and tetrabutylammonium chloride content of 0.20% by weight;

[0116] Dissolve m-phenylenediamine in deionized water to obtain an aqueous solution with a mass percentage of 2%;

[0117] Dissolve trimesoyl chloride in n-hexane to obtain an oil phase solution with a mass percentage of 0.15%;

[0118] (2) The hydrophilic treated PE base film obtained in step (1) is uniformly adsorbed on the receiver of the electrospinning device. The side view structural diagram and the top view structural diagram of the electrospinning device are shown in Figures 2 and 3 respectively, including a first spinning needle 6 and a second spinning needle 7. The first spinning needle 6 is used to absorb the polyimide mixed solution obtained in step (1), and the second spinning needle 7 is used to absorb the polysulfone mixed solution obtained in step (1). The two spinning needles are at equal vertical distances from the PE base film 1 to be spun and are arranged side by side and fixed on the electrospinning machine. The first spinning needle 6 and the second spinning needle 7 are respectively arranged in sequence along the movement direction of the PE base film 1 spinning process (as shown by arrow ①). The spacing between the two spinning needles is controlled to be 2 cm, and then the two spinning needles are placed on the electrospinning machine. The spinning needle and the receiver are connected to the positive and negative high voltages, respectively. The temperature and humidity in the transparent space where the electrospinning equipment is located are adjusted to 25°C and 45%, respectively. The positive and negative voltages are 10kV and -2kV, respectively. The receiving distance is 15cm (i.e., the vertical distance between the two spinning needles and the PE base film to be spun). The propulsion speed of the first spinning needle 6 is controlled to be 0.015mL / min, and the propulsion speed of the second spinning needle 7 is controlled to be 0.007mL / min. Finally, the two spinning needles are moved back and forth in the horizontal direction (as shown by arrow ②) for electrospinning. After the spinning is completed, they are removed, clamped between two glass plates, and baked at 100°C for 30min, thereby simultaneously forming a polymer fiber support layer and a polymer fiber hydrophilic layer with overlapping areas.

[0119] (3) The aqueous solution and the oily solution obtained in step (1) are successively coated on one side surface of the hydrophilic layer of the polymer fiber obtained in step (2), heat-treated at 90° C. for 3 min, and then washed with water at 50° C. to obtain the polymer reverse osmosis membrane.

[0120] Example 2

[0121] A polymer reverse osmosis membrane having the same structure as that of Example 1, comprising a polyolefin-based membrane, a polymer fiber support layer, a polymer fiber hydrophilic layer, and a dense functional layer arranged in sequence, wherein the polymer fiber support layer and the polymer fiber hydrophilic layer have an overlapping region in the thickness direction of the polymer reverse osmosis membrane;

[0122] The total thickness of the polyolefin base film, the polymer fiber support layer and the polymer fiber hydrophilic layer is 21 μm;

[0123] The polyolefin-based membrane is a hydrophilic-treated PE-based membrane with a thickness of 7 μm, an average pore size of 180 nm, and a porosity of 60%;

[0124] The material of the polymer fiber support layer is polyvinylidene fluoride fiber with a thickness of 10 μm and an average pore size of 350 nm;

[0125] The material of the polymer fiber hydrophilic layer is polyethersulfone fiber, with a water contact angle of 65°, a thickness of 5μm, and an average pore size of 25nm;

[0126] The thickness of the overlapping area is 1 μm, and the overlapping area accounts for 7.1% of the total thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer;

[0127] The material of the dense functional layer is polyamide, with a thickness of 100 nm;

[0128] The method for preparing the polymer reverse osmosis membrane provided in this embodiment comprises the following steps:

[0129] (1) Plasma-treating the PE base film (20 s at 2 kW) to obtain a hydrophilic PE base film;

[0130] Dissolving polyvinylidene fluoride and tetrabutylammonium chloride in DMSO to obtain a polyvinylidene fluoride mixed solution having a mass percentage content of 10% of polyvinylidene fluoride and a mass percentage content of 0.57% of tetrabutylammonium chloride;

[0131] Dissolving polyethersulfone resin and tetrabutylammonium chloride in DMSO to obtain a polyethersulfone mixed solution having a polyethersulfone resin content of 10% by weight and tetrabutylammonium chloride content of 0.19% by weight;

[0132] Dissolve m-phenylenediamine in deionized water to obtain an aqueous solution with a mass percentage of 2%;

[0133] Dissolve trimesoyl chloride in n-hexane to obtain an oil phase solution with a mass percentage of 0.15%;

[0134] (2) The hydrophilic treated PE base film obtained in step (1) is uniformly adsorbed on the receiver of the electrospinning device. The electrospinning device used in this embodiment is the same as that in embodiment 1. The first spinning needle is used to absorb the polyvinylidene fluoride solution obtained in step (1), and the second spinning needle is used to absorb the polyethersulfone mixed solution obtained in step (1). The two spinning needles are at an equal vertical distance from the PE base film to be spun and are fixed side by side on the electrospinning machine. The first spinning needle and the second spinning needle are respectively set in the direction of movement of the PE base film spinning process. The distance between the two spinning needles is controlled to be 6 cm. Then, the two spinning needles and the receiver are connected. The devices are connected to the positive and negative high voltages respectively, and the temperature and humidity in the transparent space where the electrospinning equipment is located are adjusted to 25°C and 40%, respectively, the positive and negative voltages are 20kV and -1kV, respectively, and the receiving distance is 18cm. The propulsion speed of the first spinning needle is controlled to 0.009mL / min, and the propulsion speed of the second spinning needle is controlled to 0.0038mL / min. Finally, the two spinning needles are moved back and forth in the horizontal direction for electrospinning. After the spinning is completed, they are removed, clamped between two glass plates, and baked at 100°C for 30 minutes to simultaneously form a polymer fiber support layer and a polymer fiber hydrophilic layer with overlapping areas;

[0135] (3) The aqueous solution and the oily solution obtained in step (1) are successively coated on one side surface of the hydrophilic layer of the polymer fiber obtained in step (2), heat-treated at 90° C. for 3 min, and then washed with water at 50° C. to obtain the polymer reverse osmosis membrane.

[0136] Example 3

[0137] A polymer reverse osmosis membrane having the same structure as that of Example 1, comprising a polyolefin base membrane, a polymer fiber support layer, a polymer fiber hydrophilic layer, and a polyamide functional layer arranged in sequence, wherein the polymer fiber support layer and the polymer fiber hydrophilic layer have an overlapping region in the thickness direction of the polymer reverse osmosis membrane;

[0138] The total thickness of the polyolefin base film, the polymer fiber support layer and the polymer fiber hydrophilic layer is 31

[0139] μm;

[0140] The polyolefin-based membrane is a hydrophilic-treated PE-based membrane with a thickness of 10 μm, an average pore size of 150 nm, and a porosity of 50%;

[0141] The material of the polymer fiber support layer is polyvinylidene fluoride-hexafluoropropylene fiber with a thickness of 20μm and an average pore size of 100nm.

[0142] The material of the polymer fiber hydrophilic layer is polyacrylonitrile fiber (water contact angle is 48°), with a thickness of 7 μm and an average pore size of 50 nm;

[0143] The thickness of the overlapping area is 6 μm, and the overlapping area accounts for 28.6% of the total thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer;

[0144] The material of the dense functional layer is polyamide, with a thickness of 400 nm;

[0145] The method for preparing the polymer reverse osmosis membrane provided in this embodiment comprises the following steps:

[0146] (1) Plasma-treating the PE base film (at 1.5 kW for 45 seconds) to obtain a hydrophilic PE base film;

[0147] Dissolving polyvinylidene fluoride-hexafluoropropylene and tetrabutylammonium chloride in acetone to obtain a polyvinylidene fluoride-hexafluoropropylene mixed solution having a mass percentage of 20% and a mass percentage of tetrabutylammonium chloride of 0.27%;

[0148] Dissolving polyacrylonitrile and tetrabutylammonium chloride in acetone to obtain a polyacrylonitrile mixed solution having a polyacrylonitrile content of 20% by mass and a tetrabutylammonium chloride content of 0.23% by mass;

[0149] Dissolve m-phenylenediamine in deionized water to obtain an aqueous solution with a mass percentage of 2%;

[0150] Dissolve trimesoyl chloride in n-hexane to obtain an oil phase solution with a mass percentage of 0.15%;

[0151] (2) The hydrophilic treated PE base film obtained in step (1) is uniformly adsorbed on the receiver of the electrospinning equipment, the polyvinylidene fluoride-hexafluoropropylene mixed solution obtained in step (1) is absorbed by the first spinning needle, and the polyacrylonitrile resin mixed solution obtained in step (1) is absorbed by the second spinning needle, and the two spinning needles are at equal vertical distances from the PE base film to be spun and are arranged side by side and fixed on the electrospinning machine, and the first spinning needle and the second spinning needle are respectively arranged in the direction of movement of the PE base film spinning process, and the distance between the two spinning needles is controlled to be 1 cm, and then the two spinning needles and the receiver are respectively connected. The positive and negative high voltages are connected, and the temperature and humidity in the transparent space where the electrospinning machine is located are adjusted to 25°C and 45%, respectively. The positive and negative voltages are 18kV and -2kV, respectively. The receiving distance is 15cm. The propulsion speed of the first spinning needle is controlled to 0.02mL / min, and the propulsion speed of the second spinning needle is controlled to 0.007mL / min. The two spinning needles are moved back and forth in a horizontal direction to perform electrospinning. After spinning is completed, the needles are removed, clamped between two glass plates, and baked at 100°C for 30 minutes to simultaneously form a polymer fiber support layer and a polymer fiber hydrophilic layer with overlapping areas.

[0152] (3) The aqueous solution and the oily solution obtained in step (1) are successively coated on one side surface of the hydrophilic layer of the polymer fiber obtained in step (2), heat-treated at 90° C. for 3 min, and then washed with water at 50° C. to obtain the polymer reverse osmosis membrane.

[0153] Example 4

[0154] A polymer reverse osmosis membrane, which differs from Example 1 only in that the polyolefin-based membrane is a PE-based membrane that has not been hydrophilically treated, and other materials, structures, parameters and preparation methods are the same as those of Example 1.

[0155] Examples 5-6

[0156] A polymer reverse osmosis membrane is provided, which differs from Example 1 only in that the thickness of the polyolefin-based membrane is 5 μm (Example 5) and 15 μm (Example 6), respectively. Other materials, structures, parameters and preparation methods are the same as those in Example 1.

[0157] Example 7

[0158] A polymer reverse osmosis membrane, which differs from Example 1 in that the spacing between the two spinning needles is controlled to 4.6 cm, and the propulsion speed of the first spinning needle is controlled to 0.004 mL / min, so that the polymer fiber support layer is 5 μm and the thickness of the overlapping area is 2.5 μm. Other materials, structures, parameters and preparation methods are the same as those in Example 1.

[0159] Example 8

[0160] A polymer reverse osmosis membrane, which differs from Example 1 only in that the propulsion speed of the first spinning needle is controlled to 0.023 mL / min, so that the polymer fiber support layer is 25 μm. Other materials, structures, parameters and preparation methods are the same as those in Example 1.

[0161] Example 9

[0162] A polymer reverse osmosis membrane differs from Example 1 only in that the mass percentage of tetrabutylammonium chloride in the polyimide mixed solution is controlled to 0.24%, so that the average pore size of the polymer fiber support layer is 50 nm. Other substances, structures, parameters and preparation methods are the same as those in Example 1.

[0163] Example 10

[0164] A polymer reverse osmosis membrane differs from Example 1 only in that the mass percentage of tetrabutylammonium chloride in the polyimide mixed solution is controlled to 0.85%, so that the average pore size of the polymer fiber support layer is 600 nm. Other substances, structures, parameters and preparation methods are the same as those in Example 1.

[0165] Example 11

[0166] A polymer reverse osmosis membrane, which differs from Example 1 only in that the spacing between the two spinning needles is controlled to 5.4 cm, and the propulsion speed of the second spinning needle is controlled to 0.001 mL / min, so that the thickness of the polymer fiber hydrophilic layer is 3 μm and the thickness of the overlapping area is 1.5 μm. Other substances, structures, parameters and preparation methods are the same as those in Example 1.

[0167] Example 12

[0168] A polymer reverse osmosis membrane, which differs from Example 1 only in that the propulsion speed of the second spinning needle is controlled to 0.01 mL / min so that the thickness of the polymer fiber hydrophilic layer is 10 μm. Other materials, structures, parameters and preparation methods are the same as those in Example 1.

[0169] Example 13

[0170] A polymer reverse osmosis membrane differs from Example 1 only in that the mass percentage of tetrabutylammonium chloride in the polysulfone mixed solution is controlled to 0.16%, so that the average pore size of the polymer fiber hydrophilic layer is 18 nm. Other substances, structures, parameters and preparation methods are the same as those in Example 1.

[0171] Example 14

[0172] A polymer reverse osmosis membrane differs from Example 1 only in that the mass percentage of tetrabutylammonium chloride in the polysulfone mixed solution is controlled to 0.22%, so that the average pore size of the polymer fiber hydrophilic layer is 60 nm. Other substances, structures, parameters and preparation methods are the same as those in Example 1.

[0173] Example 15

[0174] A polymer reverse osmosis membrane, which differs from Example 1 only in that the polymer fiber hydrophilic material is adjusted to polyacrylonitrile (hydrophilic contact angle of 30°) that has been corona treated for 20 seconds at a power of 3 kW. Other materials, structures, parameters and preparation methods are the same as those in Example 1.

[0175] Example 16

[0176] A polymer reverse osmosis membrane, which differs from Example 1 only in that the material for adjusting the hydrophilicity of the polymer fiber is polyvinylidene fluoride (hydrophilic contact angle is 90°) that has been corona treated for 20 seconds at a power of 3 kW, and other materials, structures, parameters and preparation methods are the same as those in Example 1.

[0177] Comparative Example 1

[0178] A polymer reverse osmosis membrane is provided, which differs from Example 1 only in that no polymer fiber support layer is provided, and other materials, structures, parameters and preparation methods are the same as those of Example 1.

[0179] Comparative Example 2

[0180] A polymer reverse osmosis membrane is provided, which differs from Example 1 only in that the polymer fiber hydrophilic layer is not provided, and other structures and parameters are the same as those of Example 1.

[0181] Comparative Example 3

[0182] A polymer reverse osmosis membrane is provided, which differs from Example 1 only in that there is no overlapping area between the polymer fiber hydrophilic layer and the polymer fiber support layer, and other structures and parameters are the same as those of Example 1.

[0183] Comparative Example 4

[0184] A polymer reverse osmosis membrane, which differs from Example 1 only in that the polymer fiber hydrophilic layer and the polymer fiber hydrophilic layer are not provided, and other structures and parameters are the same as those of Example 1.

[0185] Performance testing:

[0186] (1) Flux: The test pressure is 5 bar, and other conditions are tested in accordance with the standard GB / T 32373-2015;

[0187] (2) Water flux change rate and desalination change rate: The test pressure before and after was 5 bar, the salt solution used was 1000 ppm sodium chloride, the operating pressure was adjusted to 15 bar, and other conditions were tested in accordance with the standard GB / T 32373-2015;

[0188] (3) Solvent resistance: The solvent resistance of the multilayer composite reverse osmosis membrane was tested by weighing method. The specific method is as follows: a certain area of ​​the membrane was cut and vacuum dried. The mass of the membrane was measured by electronic balance as m1. The membrane was completely immersed in a mixture of 1 mol / L hydrochloric acid and tetrahydrofuran at 25±1°C for 7 days. The residual solvent was then washed with pure water. After vacuum drying, the mass was weighed as m2 in g. Three groups of each sample were tested in parallel. The solvent resistance was calculated using the following formula: M = m2 / m1×100%;

[0189] (4) Desalination rate: The test pressure is 5 bar, the salt solution uses 1000 ppm of sodium chloride, and other conditions are tested in accordance with standard GB / T 32373-2015.

[0190] The polymer reverse osmosis membranes provided in Examples 1 to 16 and Comparative Examples 1 to 3 were tested according to the above test method. The test results are shown in Table 1:

[0191] Table 1

[0192] According to the data in Table 1, we can see that:

[0193] The polymer reverse osmosis membranes provided in Examples 1 to 16 have high flux (3.4 LMH / bar or more), excellent pressure resistance (the absolute value of the water flux change rate is less than 7% and the absolute value of the desalination change rate is less than 5%), solvent resistance (98.8% or more), and high desalination rate (67.4% or more);

[0194] Compared with Example 1, the polymer reverse osmosis membrane provided in Comparative Example 1 is not provided with a polymer fiber support layer, and thus the pressure resistance and solvent resistance are significantly reduced; the polymer reverse osmosis membrane provided in Comparative Example 2 is not provided with a polymer fiber hydrophilic layer, which will lead to defects in the formation of a dense functional layer, and thus a significant decrease in the desalination rate; the polymer reverse osmosis membrane provided in Comparative Example 3 is not provided with an overlapping area, which will lead to poor long-term stability and easy stratification; and the polymer reverse osmosis provided in Comparative Example 4 has neither a polymer fiber support layer nor a polymer fiber hydrophilic layer, so the solvent resistance, pressure resistance and desalination rate are all reduced.

[0195] The applicant declares that while this application uses the aforementioned embodiments to illustrate a polymeric reverse osmosis membrane, its preparation method, and its application, this application is not limited to the aforementioned process steps, nor does it necessarily rely on the aforementioned process steps for implementation. Persons skilled in the art should understand that any improvements to this application, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of this application.

Claims

1. A polymer reverse osmosis membrane, which comprises a polyolefin-based membrane, and a polymer fiber support layer, a polymer fiber hydrophilic layer and a dense functional layer are sequentially arranged on the surface of the polyolefin-based membrane; There is an overlapping area between the polymer fiber support layer and the polymer fiber hydrophilic layer in the thickness direction of the polymer reverse osmosis membrane.

2. The polymer reverse osmosis membrane according to claim 1, wherein, The total thickness of the polyolefin-based membrane, the polymer fiber support layer and the polymer fiber hydrophilic layer is not higher than 40 μm.

3. The polymer reverse osmosis membrane according to claim 1 or 2, wherein, The average pore diameter of the polyolefin-based membrane is 100 - 250 nm.

4. The polymer reverse osmosis membrane according to any one of claims 1 to 3, wherein The thickness of the polyolefin-based membrane is 7 - 10 μm.

5. The polymer reverse osmosis membrane according to any one of claims 1 to 4, wherein, The porosity of the polyolefin-based membrane is 40 - 80%; Optionally, the material of the polyolefin-based membrane comprises any one or a combination of at least two of homopolymers or copolymers of ethylene, propylene, 1-butene, pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene.

6. The polymer reverse osmosis membrane according to any one of claims 1 to 5, wherein, The surface of the polyolefin-based membrane contains polar groups; Optionally, the polar group comprises any one of a hydroxyl group or a carboxyl group; Optionally, the polyolefin-based membrane is a polyolefin-based membrane after hydrophilic modification treatment.

7. The polymer reverse osmosis membrane according to any one of claims 1 to 6, wherein, The solvent resistance of the material of the polymer fiber support layer is more than 98%; Optionally, the polymer fiber support layer comprises any one of fluorine-containing fibers or polyimide fibers; Optionally, the fluorine-containing fiber comprises any one or a combination of at least two of polyvinylidene fluoride fibers, polyvinylidene fluoride - hexafluoropropylene fibers, polyvinylidene fluoride - tetrafluoroethylene fibers or polyvinylidene fluoride - chlorotrifluoroethylene fibers; Optionally, the thickness of the polymer fiber support layer is 10 - 20 μm; Optionally, the average pore diameter of the polymer fiber support layer is 100 - 500 nm.

8. The polymer reverse osmosis membrane according to any one of claims 1 to 7, wherein, The water contact angle of the material of the polymer fiber hydrophilic layer is 40 - 85°; Optionally, the thickness of the polymer fiber hydrophilic layer is 3 - 7 μm; Optionally, the average pore diameter of the polymer fiber hydrophilic layer is 20 - 50 nm; Optionally, the polymer fiber hydrophilic layer comprises any one or a combination of at least two of polyacrylonitrile fibers, polysulfone fibers, polyethersulfone fibers or sulfonated polysulfone fibers.

9. The polymer reverse osmosis membrane according to any one of claims 1 to 8, wherein, The thickness of the overlapping area is not higher than 30% of the total thickness of the polymer fiber support layer and the polymer fiber hydrophilic layer.

10. The polymer reverse osmosis membrane according to any one of claims 1 to 9, wherein, The thickness of the dense functional layer is 100 - 500 nm; Optionally, the dense functional layer is a polyamide layer; Optionally, the dense functional layer is formed by interfacial polymerization.

11. A method for preparing a polymer reverse osmosis membrane according to any one of claims 1 to 10, comprising: A polymer fiber support layer, a polymer fiber hydrophilic layer and a dense functional layer are formed on the surface of the polyolefin-based membrane to obtain the polymer reverse osmosis membrane.

12. The preparation method according to claim 11, wherein, The preparation method specifically comprises the following steps: (1) Simultaneously form a polymer fiber support layer and a polymer fiber hydrophilic layer on the surface of the polyolefin-based membrane by electrospinning; polymer fiber hydrophilic layer; (2) Form a dense functional layer on the surface of the polymer fiber hydrophilic layer by interfacial polymerization to obtain the polymer reverse osmosis membrane.

13. The preparation method according to claim 12, wherein, The polyolefin-based membrane in step (1) is subjected to hydrophilic modification treatment; Optionally, the method of the hydrophilic modification treatment comprises any one or a combination of at least two of strong acid treatment, radiation grafting treatment, coating with a hydrophilic compound or plasma treatment.

14. The preparation method according to claim 12 or 13, wherein The method for simultaneously forming the polymer fiber support layer and the polymer fiber hydrophilic layer in step (1) includes the following steps: (1A) Provide a solution containing polymer A for forming the polymer fiber support layer and a solution containing polymer B for forming the polymer fiber hydrophilic layer respectively; (1B) Use the solution containing polymer A and the solution containing polymer B in step (1A) as the spinning solutions to perform electrospinning simultaneously to form the polymer fiber support layer and the polymer fiber hydrophilic layer; Optionally, in step (1A), the mass percentage content of polymer A in the solution containing polymer A is 10-20%; Optionally, in step (1A), the mass percentage content of polymer B in the solution containing polymer B is 10-20%; Optionally, in step (1A), polymer A is at least one of fluororesin or polyimide; Optionally, in step (1A), polymer B is any one or a combination of at least two of polyacrylonitrile, polysulfone, polyethersulfone or sulfonated polysulfone; Optionally, in step (1A), the solvents in the solution containing polymer A and the solution containing polymer B independently include any one or a combination of at least two of N,N-dimethylformamide, dimethyl sulfoxide, acetone or hexafluoroisopropanol; Optionally, in step (1A), both the solution containing polymer A and the solution containing polymer B further include tetrabutylammonium chloride; Optionally, the mass percentage content of tetrabutylammonium chloride in the solution containing polymer A is 0.25-0.8%; Optionally, the mass percentage content of tetrabutylammonium chloride in the solution containing polymer B is 0.17-0.23%; Optionally, in step (1B), the distance between the two spinning needles during the electrospinning process is 1-10 cm; Optionally, the advancing speed of the spinning needle of the solution containing polymer A is 0.009-0.020 mL / min; Optionally, the advancing speed of the spinning needle of the solution containing polymer B is 0.001-0.007 mL / min.

15. Application of a polymer reverse osmosis membrane as described in any one of claims 1-10 or a polymer reverse osmosis membrane prepared by the preparation method of the polymer reverse osmosis membrane as described in any one of claims 11-14 in a water treatment device. ​

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