Reverse osmosis membrane and its preparation method and application

Abstract

A reverse osmosis membrane and its preparation method and application belong to the field of water treatment. The preparation method of the reverse osmosis membrane comprises: contacting a hydrophilically modified PE microporous membrane with an aqueous phase solution to obtain an intermediate membrane layer whose surface is infiltrated by the aqueous phase solution, wherein the aqueous phase solution contains amine monomers and terephthalic acid; contacting any surface of the intermediate membrane layer with an oil phase solution containing an acyl chloride monomer to perform an interfacial polymerization reaction, and drying. The improvement of the above preparation method is used to obtain a high-throughput acid-resistant reverse osmosis membrane, so that it can perform high-throughput treatment of acid solutions.

Description

Technical Field

[0001] The present application relates to the field of water treatment, and in particular to a reverse osmosis membrane and a preparation method and application thereof. Background Art

[0002] Reverse osmosis membrane plays an important role in the field of membrane technology. Reverse osmosis membrane technology uses the pressure difference on both sides of the membrane as the driving force to make the solvent (usually water) selectively pass through the membrane to achieve the separation of solvent and solute. It has the advantages of no phase change, low energy consumption, small footprint, simple operation, strong adaptability, and less environmental pollution. It has a good prospect in the fields of industrial wastewater treatment, reclaimed water reuse, seawater desalination, etc.

[0003] Traditional reverse osmosis membranes have poor acid resistance and are not suitable for acid solution treatment. Even if they are used in acid solution treatment, they are easily destroyed by hydrogen ions and cannot exist stably, resulting in surface damage, reduced flux and salt rejection rate. Summary of the invention

[0004] The present application provides a reverse osmosis membrane and a preparation method and application thereof, which can improve the problem of poor acid resistance of existing reverse osmosis membranes and low flux in acid solution treatment.

[0005] The embodiment of the present application is implemented as follows:

[0006] In the first aspect, the present application provides an example of a method for preparing a reverse osmosis membrane, which includes the following steps: contacting a hydrophilically modified PE microporous membrane with an aqueous solution to obtain an intermediate membrane layer whose surface is wetted by the aqueous solution, wherein the aqueous solution contains amine monomers and terephthalic acid; contacting any surface of the intermediate membrane layer with an oil phase solution containing an acyl chloride monomer to carry out an interfacial polymerization reaction, and drying.

[0007] In the technical scheme of the embodiment of the present application, an interfacial polymerization reaction is carried out using amine monomers and acyl chloride monomers to generate a cross-linked polyamide layer formed on the surface of the PE microporous membrane. The terephthalic acid contained in the aqueous phase solution is used as an additive to promote and enhance the polymerization reaction of the acyl chloride monomers and the amine monomers, improve the efficiency of the polymerization reaction and the degree of cross-linking, and improve the acid resistance of the cross-linked polyamide layer. During the polymerization reaction, stable conjugated bonds are generated between the amine monomers and the terephthalic acid, and the conjugated bonds are used to enhance the structural stability and mechanical stability of the reverse osmosis membrane, further improving its acid resistance. On the other hand, it is used as a reactive monomer so that it can undergo a polymerization reaction with the acyl chloride monomer to be tightly anchored in the cross-linked polyamide layer network, so as to increase the number of hydrogen bonds in the cross-linked polyamide layer and introduce carboxyl groups, thereby improving the hydrophilicity of the reverse osmosis membrane, which is beneficial to the movement of water molecules and passing through the reverse osmosis membrane, that is, improving the water permeability of the reverse osmosis membrane.

[0008] In summary, the above preparation method is used to obtain a high-flux acid-resistant reverse osmosis membrane, which is capable of high-flux treatment of acid solutions.

[0009] In some embodiments, the content of terephthalic acid in the aqueous solution is 0.1 wt % to 0.6 wt %.

[0010] In some embodiments, before any surface of the membrane layer contacts the oil phase solution containing the acyl chloride monomer, the preparation method further comprises: placing the intermediate membrane layer in air to dry so that sparsely distributed stripes appear on its surface to reach a semi-dry state, and then contacting the intermediate membrane layer in the semi-dry state with the oil phase solution.

[0011] In some embodiments, the step of contacting the PE microporous membrane with the aqueous solution comprises: immersing the PE microporous membrane in the aqueous solution for 0.5-3 minutes, and then rolling the membrane at a constant speed at least once to remove excess aqueous solution on the surface.

[0012] In some embodiments, the drying temperature is 55° C.-70° C., and the drying time is 1 min-2 min.

[0013] In some embodiments, the content of the amine monomer in the aqueous solution is 2 wt %-5 wt %.

[0014] Optionally, the amine monomer includes at least one of m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, and N-aminoethylpiperazine.

[0015] Optionally, the amine monomer is m-phenylenediamine.

[0016] In some embodiments, the acid chloride monomer includes at least one of cyanuric chloride, trimesoyl chloride, terephthaloyl chloride, isophthaloyl chloride, and phthaloyl chloride.

[0017] In some embodiments, the acyl chloride monomer is a combination of cyanuric chloride and trimesoyl chloride, wherein the amount of cyanuric chloride added to the oil phase solution is 0.2 wt %-1 wt %, and the amount of trimesoyl chloride added to the oil phase solution does not exceed 0.5 wt %.

[0018] In some embodiments, the acyl chloride monomer is cyanuric chloride, and the amount of cyanuric chloride added to the oil phase solution is 0.2wt%-1wt%. Within the above range, the reaction effect with the amine monomer is good, which is convenient for forming a cross-linked polyamide layer.

[0019] In some embodiments, the solvent of the oil phase solution includes at least one of n-hexane, acetone, toluene, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0020] In some embodiments, the hydrophilic modification step includes: immersing the PE microporous membrane in a polyol aqueous solution for 5s-20s, and then washing the obtained membrane with water, wherein the content of the polyol in the polyol aqueous solution is not less than 10wt%.

[0021] Optionally, the polyol is selected from at least one of C2-C5 polyols.

[0022] In some embodiments, the porosity of the PE microporous membrane is 44%-47% and the surface density is 10 g / cm 2 -11g / cm 2 .

[0023] In a second aspect, the present application provides an example of a reverse osmosis membrane, which is prepared by the preparation method provided in any of the above embodiments.

[0024] In the technical solution of the embodiment of the present application, the reverse osmosis membrane prepared by the above-mentioned preparation method has high flux, high desalination rate and stable acid resistance, so that it can perform high-throughput treatment of acid solutions.

[0025] In a third aspect, the present application example provides an application of the above-mentioned reverse osmosis membrane in water treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the reverse osmosis membrane process provided in this application. DETAILED DESCRIPTION

[0028] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0029] Traditional reverse osmosis membranes have poor acid resistance and are not suitable for acid solution treatment. Even if they are used in acid solution treatment, they are easily destroyed by hydrogen ions and cannot exist stably, resulting in surface damage, reduced flux and salt rejection rate.

[0030] In order to improve the problem of poor acid resistance of existing reverse osmosis membranes and low flux in acid solution treatment, the inventors of the present application attempt to use amine monomers and acyl chloride monomers for interfacial polymerization to generate a cross-linked polyamide layer formed on the surface of the PE microporous membrane during the preparation process of the reverse osmosis membrane, and use terephthalic acid contained in the aqueous phase solution during the preparation process to promote and enhance the polymerization reaction of the acyl chloride monomers and the amine monomers, improve the efficiency and cross-linking degree of the polymerization reaction, and improve the acid resistance of the cross-linked polyamide layer. During the polymerization reaction, stable conjugated bonds are generated between the amine monomers and terephthalic acid, and the conjugated bonds are used to enhance the structural stability and mechanical stability of the reverse osmosis membrane, further improving its acid resistance. On the other hand, it is used as a reactive monomer so that it can undergo polymerization reaction with the acyl chloride monomer to be tightly anchored in the cross-linked polyamide layer network, so as to increase the number of hydrogen bonds in the cross-linked polyamide layer and introduce carboxyl groups, thereby improving the hydrophilicity of the reverse osmosis membrane, facilitating the movement of water molecules and passing through the reverse osmosis membrane, and improving the water permeability of the reverse osmosis membrane.

[0031] In summary, the above preparation method is used to obtain a high-flux acid-resistant reverse osmosis membrane, which is capable of high-flux treatment of acid solutions.

[0032] like Figure 1 As shown, the present application provides a method for preparing a reverse osmosis membrane, which comprises the following steps:

[0033] S1. The hydrophilically modified PE microporous membrane is brought into contact with an aqueous solution to obtain an intermediate membrane layer whose surface is wetted by the aqueous solution, wherein the aqueous solution contains amine monomers and terephthalic acid.

[0034] Since the PE microporous membrane is hydrophobic, its affinity with the aqueous solution is very poor, and it is difficult to directly prepare a polyamide layer on its surface by interfacial polymerization. Therefore, it is necessary to use a hydrophilically modified PE microporous membrane in contact with the aqueous solution to obtain an intermediate membrane layer whose surface is infiltrated with the aqueous solution, which is equivalent to forming a wetting modification layer composed of the aqueous solution on the surface of the PE microporous membrane, so as to facilitate the subsequent contact with the oil phase solution and interfacial reaction in step S2.

[0035] PE microporous membrane refers to a polyethylene film with micron-sized pores. Since PE not only has excellent chemical stability and excellent mechanical strength, but also has low cost and is non-toxic, it is used as a supporting membrane layer for forming a reverse osmosis membrane in this application.

[0036] Optionally, the porosity of the PE microporous membrane is 44%-47% and the surface density is 10g / cm 2 -11g / cm 2 Under this setting, the choice of PE microporous membrane is beneficial to reduce concentration polarization, while reducing membrane resistance, increasing forward osmosis membrane water flux and reducing reverse salt flux.

[0037] It should be noted that the hydrophilically modified PE microporous membrane can be purchased directly from the market or prepared by oneself.

[0038] Optionally, in some embodiments, the hydrophilic modification step comprises: immersing the PE microporous membrane in a polyol aqueous solution for 5s-20s, and then washing the resulting membrane with water, wherein the content of the polyol in the polyol aqueous solution is not less than 10wt%.

[0039] The above hydrophilic modification step is not only simple to operate, but also takes a short time and has little influence on the membrane making process.

[0040] Illustratively, in the hydrophilic modification step, the PE microporous membrane is immersed in a polyol aqueous solution for any value of 5s, 7s, 9s, 10s, 12s, 15s, 17s, 20s or between any two values, and then washed with water.

[0041] Optionally, the polyol is selected from at least one of C2-C5 polyols, which are easy to obtain, have good hydrophilic modification effects and are low in cost.

[0042] Exemplarily, the polyol is ethanol, which is not only easily available but also has a good hydrophilic modification effect and low cost.

[0043] The step of contacting the PE microporous membrane with the aqueous solution includes but is not limited to coating, dipping, spraying and the like.

[0044] Optionally, in some embodiments, the step of contacting the PE microporous membrane with the aqueous solution comprises: immersing the PE microporous membrane in the aqueous solution for 0.5-3 min, and then rolling the membrane at a constant speed at least once to remove excess aqueous solution on the surface.

[0045] The above-mentioned contact method of uniform rolling after dipping is beneficial to the formation of a uniformly distributed impregnation modification layer on the surface of the PE microporous membrane, which is beneficial to its subsequent reaction with the oil phase solution to obtain a cross-linked polyamide layer uniformly distributed on the surface of the PE microporous membrane, thereby improving the service life of the reverse osmosis membrane and being beneficial to the reverse osmosis membrane having high flux, high desalination rate and stable acid resistance.

[0046] Among them, terephthalic acid is a carboxylic acid monomer, which is partially soluble in water, alcohol and ether at room temperature. Compared with inorganic acids, it is a solid acid with high catalytic activity, high stability and low corrosiveness. Terephthalic acid has excellent catalytic activity and high stability. Terephthalic acid can not only produce stable conjugated bonds with amine monomers, and use conjugated bonds to enhance the structural stability and mechanical stability of the reverse osmosis membrane, but also terephthalic acid can directly participate in the formation of the reverse osmosis membrane to improve the structural stability and mechanical stability of the reverse osmosis membrane, so that the reverse osmosis membrane can stably exist in the acid solution, thereby improving the acid resistance of the reverse osmosis membrane.

[0047] The content of terephthalic acid in the aqueous solution is 0.1wt%-0.6wt%. Within the above range, the content of terephthalic acid in the aqueous solution is reasonable, which can effectively improve the acid resistance and flux of the reverse osmosis membrane.

[0048] Illustratively, the content of terephthalic acid in the aqueous solution is any one of 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, or between any two values.

[0049] Optionally, in some embodiments, the content of the amine monomer in the aqueous solution is 2 wt %-5 wt %. The content within the above range is reasonable and can undergo polymerization reaction with the acyl chloride monomer to obtain a cross-linked polyamide layer of reasonable thickness.

[0050] Illustratively, the content of the amine monomer in the aqueous solution is any one of 2 wt %, 3 wt %, 4 wt %, 5 wt %, or between any two values.

[0051] Optionally, in some embodiments, the amine monomer includes at least one of m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, and N-aminoethylpiperazine. For example, the amine monomer is m-phenylenediamine, or o-phenylenediamine, or a combination of m-phenylenediamine and p-phenylenediamine, etc., and technicians with skills in the art can make a selection based on actual needs.

[0052] Optionally, in some embodiments, the amine monomer is m-phenylenediamine.

[0053] S2. Contacting any surface of the intermediate film layer with an oil phase solution containing an acyl chloride monomer to carry out an interfacial polymerization reaction, and then drying.

[0054] Since the surface of the intermediate membrane layer is infiltrated by the aqueous solution, when any surface of the intermediate membrane layer is contacted with the oil phase solution containing the acyl chloride monomer, the amine monomer and the acyl chloride monomer undergo interfacial polymerization reaction, thereby generating a cross-linked polyamide layer formed on the surface of the PE microporous membrane, and during the polymerization process, terephthalic acid can not only promote and enhance the polymerization reaction of the acyl chloride monomer and the amine monomer, improve the efficiency and cross-linking degree of the polymerization reaction, and improve the acid resistance of the cross-linked polyamide layer, but also during the polymerization reaction, a stable conjugated bond is generated between the amine monomer and terephthalic acid, and the conjugated bond is used to enhance the structural stability and mechanical stability of the reverse osmosis membrane, and further improve its acid resistance. In addition, terephthalic acid can also undergo polymerization reaction with the acyl chloride monomer to be tightly anchored in the cross-linked polyamide layer network, so as to increase the number of hydrogen bonds in the cross-linked polyamide layer and introduce carboxyl groups, thereby improving the hydrophilicity of the reverse osmosis membrane, which is beneficial to the movement of water molecules and passing through the reverse osmosis membrane, that is, improving the water permeability of the reverse osmosis membrane.

[0055] In order to improve the uniformity of the final cross-linked polyamide layer, thereby improving the service life, flux, desalination rate and acid resistance of the reverse osmosis membrane, optionally, in some embodiments, before any surface of the membrane layer contacts the oil phase solution containing the acyl chloride monomer, the preparation method also includes: placing the intermediate membrane layer in the air to dry so that sporadically distributed stripes appear on its surface to achieve a semi-dry state, and then contacting the intermediate membrane layer in the semi-dry state with the oil phase solution.

[0056] The method of contacting the intermediate membrane layer with the oil phase solution is conducive to the interfacial polymerization reaction of the acyl chloride monomer and the amine monomer at the contact surface, thereby forming a cross-linked polyamide layer uniformly loaded on the surface of the PE microporous membrane.

[0057] The method of contacting any surface of the intermediate film layer with the oil phase solution containing the acyl chloride monomer includes but is not limited to coating, and may also be dipping, spraying, and the like.

[0058] Optionally, in some embodiments, the step of contacting any surface of the intermediate film layer with an oil phase solution containing acyl chloride monomers comprises: immersing any surface of the intermediate film layer in the oil phase solution for 0.5-1 min, and then rolling at a constant speed at least once to remove excess oil phase solution on the surface.

[0059] The contact method of uniform rolling after dipping is beneficial to forming an evenly distributed oil phase layer on the surface of the functional layer, so that it reacts with the interface of the functional layer to form a cross-linked polyamide layer evenly distributed on the surface of the PE microporous membrane, which can not only improve the service life of the reverse osmosis membrane, but also help to obtain high flux, high desalination rate and stable acid resistance.

[0060] Optionally, the drying temperature is 55° C.-70° C., and the drying time is 1 min-2 min. Within the above range, the reverse osmosis membrane can be effectively dried without causing damage to its performance.

[0061] Exemplarily, the drying temperature is any value among 55°C, 60°C, 65°C, 70°C or between any two values, and the drying time is any value among 1 min, 1.2 min, 1.5 min, 1.7 min, 2 min or between any two values.

[0062] Optionally, the acyl chloride monomer includes at least one of cyanuric chloride, trimesoyl chloride, terephthaloyl chloride, isophthaloyl chloride and phthaloyl chloride. For example, the acyl chloride monomer is cyanuric chloride, or the acyl chloride monomer is a combination of cyanuric chloride and trimesoyl chloride, etc. Those skilled in the art can select according to actual needs.

[0063] Optionally, in some embodiments, the acyl chloride monomer is a combination of cyanuric chloride and trimesoyl chloride, wherein the amount of cyanuric chloride added to the oil phase solution is 0.2 wt %-1 wt %, and the amount of trimesoyl chloride added to the oil phase solution does not exceed 0.5 wt %.

[0064] Optionally, in some embodiments, the acyl chloride monomer is cyanuric chloride, and the amount of cyanuric chloride added to the oil phase solution is 0.2 wt %-1 wt %.

[0065] Optionally, in some embodiments, the solvent of the oil phase solution includes at least one of n-hexane, acetone, toluene, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0066] The present application also provides a reverse osmosis membrane prepared by the preparation method provided by any of the above embodiments, and the reverse osmosis membrane has high flux, high desalination rate and stable acid resistance, so it is not only suitable for conventional water treatment, but also can perform high-throughput treatment of acid solutions.

[0067] The reverse osmosis membrane comprises a PE microporous membrane and a functional layer formed on any surface of the PE microporous membrane, wherein the functional layer is a cross-linked polyamide in which terephthalic acid participates in the reaction.

[0068] The present application also provides application of the above reverse osmosis membrane in water treatment.

[0069] The water treatment here includes but is not limited to industrial wastewater treatment, reclaimed water reuse, seawater desalination and other fields.

[0070] Optionally, in some embodiments, the pH value of the water is <7.

[0071] That is, the application of the above-mentioned reverse osmosis membrane in treating acid solutions is provided herein, and the acid solutions treated herein include but are not limited to industrial acid extraction, treatment of acidic wastewater in the electroplating industry, treatment of acidic wastewater in biological fermentation, etc.

[0072] The reverse osmosis membrane of the present application and its preparation method and application are further described in detail below in conjunction with embodiments.

[0073] The PE microporous membrane used in the following examples and comparative examples is the same, and the surface density of the PE microporous membrane is 10 g / cm 2 , the porosity is 47%.

[0074] Example 1

[0075] The PE microporous membrane was immersed in a 50wt% ethanol solution for 10s, washed with deionized water and taken out, immersed in an aqueous solution containing m-phenylenediamine (2.8wt%) and terephthalic acid (0.1wt%) for 1min, rolled twice at a uniform speed, and immersed in an Isopar E solution of cyanuric chloride (0.2wt%) for 50s on one side under semi-dry conditions, rolled at a uniform speed to remove excess liquid, and then dried in an oven at 60°C for 2min to obtain a reverse osmosis membrane.

[0076] 500ppm NaCl, 8bar test rejection rate is 99.5%, membrane flux is 5.5L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 99.3% and the membrane flux was 5.7L / (m 2 *h*bar).

[0077] Example 2

[0078] The PE microporous membrane was immersed in a 50wt% ethanol solution for 10s, washed with deionized water and taken out, immersed in an aqueous solution containing m-phenylenediamine (2.8wt%) and terephthalic acid (0.3%) for 1min, rolled twice at a uniform speed, and immersed in an Isopar E solution of cyanuric chloride (0.2wt%) for 50s on one side under semi-dry conditions, rolled to remove excess liquid, and then dried in an oven at 60°C for 2min to obtain a reverse osmosis membrane.

[0079] 500ppm NaCl, 8bar test rejection rate is 99.7%, membrane flux is 5.2L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 99.4% and the membrane flux was 5.4L / (m 2 *h*bar).

[0080] Example 3

[0081] The PE microporous membrane was immersed in a 50wt% ethanol solution for 10s, washed with deionized water and taken out, immersed in an aqueous solution containing m-phenylenediamine (2.8wt%) and terephthalic acid (0.5wt%) for 1min, rolled twice at a uniform speed, and immersed in an Isopar E solution of cyanuric chloride (0.2wt%) for 50s on one side under semi-dry conditions, rolled at a uniform speed to remove excess liquid, and then dried in an oven at 60°C for 2min to obtain a reverse osmosis membrane.

[0082] 500ppm NaCl, 8bar test rejection rate is 99.8%, membrane flux is 5.0L / (m 2*h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 99.4% and the membrane flux was 5.0L / (m 2 *h*bar).

[0083] Example 4

[0084] The PE microporous membrane was immersed in a 50wt% ethanol solution for 10s, washed with deionized water and taken out, immersed in an aqueous solution containing m-phenylenediamine (2.8wt%) and terephthalic acid (0.5wt%) for 1min, rolled at a constant speed twice, and immersed in an Isopar E solution of cyanuric chloride (0.2wt%) and trimesoyl chloride (0.1wt%) for 50s on one side under semi-dry conditions, rolled at a constant speed to remove excess liquid, and then dried in an oven at 60°C for 2min to obtain a reverse osmosis membrane.

[0085] 500ppm NaCl, 8bar test rejection rate is 99.8%, membrane flux is 5.0L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 99.4% and the membrane flux was 5.0L / (m 2 *h*bar).

[0086] Example 5

[0087] The only difference between this embodiment and Example 1 is that the content of terephthalic acid in the aqueous phase solution is 0.6 wt %.

[0088] 500ppm NaCl, 8bar test rejection rate is 98.8%, membrane flux is 5.3L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 98.5% and the membrane flux was 5.5L / (m 2 *h*bar).

[0089] Example 6

[0090] The only difference between the above-mentioned example and Example 1 is that the above-mentioned example is dried in an oven at 55° C. for 2 minutes.

[0091] 500ppm NaCl, 8bar test rejection rate is 98.5%, membrane flux is 5L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 98.0% and the membrane flux was 5.1L / (m 2 *h*bar).

[0092] Example 7

[0093] The only difference between the above-mentioned example and Example 1 is that the above-mentioned example is dried in an oven at 70° C. for 2 minutes.

[0094] 500ppm NaCl, 8bar test rejection rate is 98.7%, membrane flux is 4.9L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 98.5% and the membrane flux was 5.1L / (m 2 *h*bar).

[0095] Comparative Example 1

[0096] The PE microporous membrane was immersed in a 50wt% ethanol solution for 10s, washed with deionized water and taken out, immersed in an aqueous solution containing m-phenylenediamine (2.8wt%) for 1min, rolled twice at a constant speed, and immersed in a single-side surface of cyanuric chloride (0.2wt%) Isopar E solution for 50s under semi-dry conditions, rolled at a constant speed to remove excess liquid, and then dried in an oven at 60°C for 2min to obtain a reverse osmosis membrane.

[0097] 500ppm NaCl, 8bar test rejection rate is 92.1%, membrane flux is 2.7L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 85% and the membrane flux was 3.8L / (m 2 *h*bar).

[0098] Comparative Example 2

[0099] The only difference between this embodiment and Example 1 is that the content of terephthalic acid in the aqueous phase solution is 1 wt %.

[0100] 500ppm NaCl, 8bar test rejection rate is 98.1%, membrane flux is 4.7L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 97.9% and the membrane flux was 4.8L / (m 2 *h*bar).

[0101] Comparative Example 3

[0102] The PE microporous membrane was immersed in an Isopar E solution of cyanuric chloride (0.2wt%) for 50s, dried, and then either surface thereof was immersed in an aqueous solution containing m-phenylenediamine (2.8wt%) for 1min, rolled twice at a uniform speed, and then dried in an oven at 60°C for 2min to obtain a reverse osmosis membrane.

[0103] 500ppm NaCl, 8bar test rejection rate is 95%, membrane flux is 3.1L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 94.8% and the membrane flux was 3.5L / (m 2 *h*bar).

[0104] Comparative Example 4

[0105] The only difference between the above-mentioned example and Example 1 is that the above-mentioned example is dried in an oven at 90° C. for 2 minutes.

[0106] 500ppm NaCl, 8bar test rejection rate is 94%, membrane flux is 3.5L / (m 2 *h*bar).

[0107] After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 93% and the membrane flux was 3.5L / (m 2 *h*bar).

[0108] Comparative Example 5

[0109] The only difference between the above-mentioned example and Example 1 is that the above-mentioned example is dried in an oven at 60° C. for 10 min.

[0110] 500ppm NaCl, 8bar test rejection rate is 96.2%, membrane flux is 4.5L / (m 2 *h*bar). After the reverse osmosis membrane was immersed in an acid solution containing 20wt% sulfuric acid and 5wt% HCl for 48h, the test rejection rate was 96.1% and the membrane flux was 4.6L / (m 2 *h*bar).

[0111] In summary, the reverse osmosis membrane provided in the present application utilizes an improvement in its preparation method to obtain a high-flux acid-resistant reverse osmosis membrane, so that it can perform high-flux treatment of acid solutions.

[0112] The above are only specific embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a high-flux acid-resistant reverse osmosis membrane, characterized in that: The following steps are involved: The hydrophilically modified PE microporous membrane is brought into contact with an aqueous solution to obtain an intermediate membrane layer whose surface is infiltrated by the aqueous solution, wherein the aqueous solution contains an amine monomer and terephthalic acid; contacting any surface of the intermediate film layer with an oil phase solution containing an acyl chloride monomer to carry out an interfacial polymerization reaction, and drying; The drying temperature is 55°C-70°C, and the drying time is 1min-2min. The content of terephthalic acid in the aqueous solution is 0.1 wt %-0.6 wt %.

2. The preparation method according to claim 1, characterized in that: Before any surface of the membrane layer contacts the oil phase solution containing the acyl chloride monomer, the preparation method further comprises: placing the intermediate membrane layer in air to dry so that scattered stripes appear on its surface to reach a semi-dry state, and then contacting the intermediate membrane layer in the semi-dry state with the oil phase solution.

3. The preparation method according to claim 1, characterized in that: The step of contacting the PE microporous membrane with the aqueous solution comprises: immersing the PE microporous membrane in the aqueous solution for 0.5-3 minutes, and then rolling at a constant speed at least once to remove excess aqueous solution on the surface.

4. The preparation method according to claim 1, characterized in that: The step of contacting any surface of the intermediate film layer with the oil phase solution containing the acyl chloride monomer comprises: immersing any surface of the intermediate film layer in the oil phase solution for 0.5-1 min, and then rolling at a constant speed at least once to remove excess oil phase solution on the surface.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The content of the amine monomer in the aqueous phase solution is 2wt%-5wt%.

6. The preparation method according to any one of claims 1 to 4, characterized in that The amine monomer includes at least one of m-phenylenediamine, o-phenylenediamine, p-phenylenediamine and N-aminoethylpiperazine.

7. The preparation method according to any one of claims 1 to 4, characterized in that: The amine monomer is m-phenylenediamine.

8. The preparation method according to any one of claims 1 to 4, characterized in that: The acyl chloride monomer includes at least one of cyanuric chloride, trimesoyl chloride, terephthaloyl chloride, isophthaloyl chloride and phthaloyl chloride.

9. The preparation method according to any one of claims 1 to 4, characterized in that: The acyl chloride monomer is a combination of cyanuric chloride and trimesoyl chloride, wherein the amount of cyanuric chloride added to the oil phase solution is 0.2wt%-1wt%, and the amount of trimesoyl chloride added to the oil phase solution does not exceed 0.5wt%.

10. The preparation method according to any one of claims 1 to 4, characterized in that: The acyl chloride monomer is cyanuric chloride, and the amount of cyanuric chloride added to the oil phase solution is 0.2wt%-1wt%.

11. The preparation method according to any one of claims 1 to 4, characterized in that: The solvent of the oil phase solution includes at least one of n-hexane, acetone, toluene, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.

12. The preparation method according to any one of claims 1 to 4, characterized in that: The hydrophilic modification step comprises: immersing the PE microporous membrane in a polyol aqueous solution for 5s-20s, and then washing the membrane with water, wherein the content of the polyol in the polyol aqueous solution is not less than 10wt%.

13. The preparation method according to claim 12, characterized in that: The polyol is selected from at least one of C2-C5 polyols.

14. The preparation method according to any one of claims 1 to 4, characterized in that The porosity of the PE microporous membrane is 44%-47% and the surface density is 10 g / cm 2 -11g / cm 2 .

15. A high flux acid-resistant reverse osmosis membrane, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 14.

16. Use of the high-flux acid-resistant reverse osmosis membrane according to claim 15 in water treatment.

17. The use according to claim 16, characterized in that The pH value of the water is <7.

Images