High-temperature-resistant nanofiltration membrane as well as preparation method and application thereof

Abstract

The invention discloses a high-temperature-resistant nanofiltration membrane and a preparation method and application thereof.The preparation method of the high-temperature-resistant nanofiltration membrane comprises the steps that a base membrane is soaked in an aniline oxidation prepolymerization solution and a cross-linking agent solution for a period of time and then taken out, the base membrane is washed with pure water, then the base membrane is placed at the temperature of 80-100 DEG C to be heated for 5-15 min, and the high-temperature-resistant nanofiltration membrane is prepared; the base membrane is one of a polysulfone membrane, a polyimide membrane and a meta-aramid membrane; the base membrane is soaked in the aniline oxidation prepolymerization liquid, taken out, washed with pure water and then soaked in the cross-linking agent solution, or the base membrane is soaked in the cross-linking agent solution, taken out, washed with pure water and then soaked in the aniline oxidation prepolymerization liquid. The aniline can generate a multi-heterocyclic ring conjugated polymer compound under the action of a strong oxidant, and a benzene ring and a nitrogen-containing heterocyclic ring exist in the structure, so that the rigidity of a molecular chain is relatively strong, and the influence of temperature on thermal motion of the molecular chain is relatively small.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanofiltration membranes, and in particular relates to a high temperature resistant nanofiltration membrane and a preparation method and application thereof. Background Art

[0002] Most commercial nanofiltration membranes are thin-layer composite membranes based on interfacial polymerization. The base membrane is prepared by the phase inversion method, while the separation layer is generated by the reaction of oil phase monomers and water phase monomers on the surface of the support membrane. The performance of the membrane is affected by factors such as the nature of the base membrane, the type of monomers, and the degree of cross-linking. In the separation process at room temperature, commercial nanofiltration membranes have excellent performance, but in high-temperature application environments such as hot water disinfection, condensate desalination, and high-temperature material separation, most nanofiltration membranes cannot meet the requirements. The reason is that the thermal motion of the polymer chain is accelerated, the free volume increases, the membrane pore size changes, the retention performance is greatly attenuated, and its stability and durability are also significantly reduced. Therefore, the operating temperature of most commercial nanofiltration membranes is usually limited to below 50°C. For example, the product instructions of most commercial nanofiltration membranes clearly stipulate that the maximum operating temperature of the nanofiltration membrane shall not exceed 50°C.

[0003] In order to obtain high-temperature resistant polymer nanofiltration membranes, researchers often use heat-resistant engineering polymers such as polyetheretherketone, polyimide, polybenzimidazole, aramid and other materials to synthesize base membranes, and then prepare a selective separation layer with a high degree of cross-linking by strengthening the interfacial reaction to obtain a heat-resistant composite nanofiltration membrane, such as by increasing the interfacial polymerization temperature. There are also studies that directly use conjugated aromatic structure polymers such as polyphenyl rings and hybrid polymers (sulfonated polyethersulfoneketone, sulfonated poly(naphthalene)diphenyl copolyethersulfone) as the selective separation layer materials of nanofiltration membranes to prepare temperature-resistant nanofiltration membranes. Other researchers have added inorganic nanomaterials to the separation layer of thin composite membranes to limit the movement of polymer chains in the separation layer and reduce deformation caused by high temperature. These methods have high requirements for the preparation process and harsh conditions. Summary of the invention

[0004] In order to solve the above technical problems, the object of the present invention is to provide a method for preparing a high-temperature resistant nanofiltration membrane which has a simple preparation method and good high-temperature resistance.

[0005] In order to achieve the above object, the technical scheme of the present invention is as follows: a method for preparing a high temperature resistant nanofiltration membrane, wherein the base membrane is soaked in an aniline oxidation prepolymer solution and a cross-linking agent solution for a period of time, taken out, and rinsed with pure water, and then the base membrane is heated at 80-100°C for 5-15 minutes to obtain a high temperature resistant nanofiltration membrane;

[0006] Wherein, the base membrane is one of a polysulfone membrane, a polyimide membrane, and a meta-aramid membrane;

[0007] The base film is first soaked in the aniline oxidation prepolymer solution, taken out, rinsed with pure water and then soaked in the crosslinker solution, or the base film is first soaked in the crosslinker solution, taken out, rinsed with pure water and then soaked in the aniline oxidation prepolymer solution.

[0008] The preparation method of the base film in the above technical solution is as follows:

[0009] A polymer solution is prepared by using a polymer and an additive as solutes, wherein the polymer is one of polysulfone, polyimide and meta-aramid;

[0010] The polymerization solution is heated and allowed to stand for degassing;

[0011] The defoamed polymer solution is coated on the non-woven fabric and immersed in pure water for solidification to obtain a base film with the non-woven fabric as a support carrier;

[0012] The prepared basement membrane was placed in pure water for later use.

[0013] The method for preparing the base film in the above technical solution satisfies at least one of the following conditions:

[0014] a1: the additive is polyvinyl pyrrolidone, polyethylene glycol or lithium chloride;

[0015] b1: The non-woven fabric is a polyester non-woven fabric or a polypropylene non-woven fabric;

[0016] c1: the concentration of the polymer in the polymer solution is 12-22 wt%;

[0017] d1: the additive content in the polymer solution is 1-5wt%;

[0018] e1: the solvent of the polymer solution is at least one of N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone;

[0019] f1: The degassing temperature is 50-100℃.

[0020] The preparation method of the aniline oxidation prepolymer solution described in the above technical scheme is as follows:

[0021] Aniline substances and oxidants are used as solutes to prepare aniline oxidation prepolymerization liquid, and the aniline oxidation prepolymerization liquid is prepolymerized for a period of time, wherein the aniline substances are phenylenediamine and / or its derivatives.

[0022] The method for preparing the aniline oxidation prepolymer solution in the above technical solution satisfies at least one of the following conditions:

[0023] a2: the concentration of aniline substances in the aniline oxidation prepolymer solution is 0.01-2wt%;

[0024] b2: the concentration of the oxidant 1 in the aniline oxidation prepolymer solution is 0.01-0.4wt%;

[0025] c2: the solvent of the aniline oxidation prepolymer solution is at least one of water, methanol, ethanol and propanol;

[0026] d2: Oxidant 1 is sodium peroxodisulfate, potassium persulfate or potassium permanganate;

[0027] e2: The duration of prepolymerization is 1-120 min;

[0028] f2: The phenylenediamine derivative includes at least one of p-phenylenediamine, m-phenylenediamine, p-phenylenediamine sulfonic acid and m-phenylenediamine sulfonic acid.

[0029] The preparation method of the cross-linking agent solution in the above technical solution is as follows:

[0030] A crosslinking agent solution is prepared by taking a crosslinking agent and a second oxidizing agent as solutes, wherein the crosslinking agent is catechol, pyrogallol, tannic acid, gallic acid, glutaraldehyde or 1,3-isophthalaldehyde.

[0031] The method for preparing the crosslinking agent solution in the above technical solution satisfies at least one of the following conditions:

[0032] a3: the concentration of the crosslinking agent in the crosslinking agent solution is 0.1-0.4wt%;

[0033] b3: the solvent of the cross-linking agent solution is at least one of water, methanol, ethanol and propanol;

[0034] c3: Oxidant 2 is sodium periodate, potassium persulfate or hydrogen peroxide;

[0035] d3: The concentration of the second oxidant in the cross-linking agent solution is 0-0.4 wt%.

[0036] In the above technical solution, the base film is immersed in the aniline oxidation prepolymer solution for 3-60 minutes; the base film is immersed in the cross-linking agent solution for 5-120 minutes.

[0037] The second object of the present invention is to provide a high temperature resistant nanofiltration membrane prepared by the above preparation method.

[0038] The third object of the present invention is to provide a high temperature resistant nanofiltration membrane as described above for use in condensate desalination, high temperature material separation or filtration processes requiring regular high temperature hot water disinfection.

[0039] The beneficial effects of the present invention are as follows: since aniline can generate a polycyclic heterocyclic conjugated polymer complex under the action of a strong oxidant, and since the structure contains a benzene ring and a nitrogen-containing heterocyclic ring, the molecular chain has strong rigidity, and the thermal motion of the molecular chain is less affected by temperature. Since a large number of unreacted amine groups remain in the complex, it can continue to react with aldehyde groups and polyphenols. By performing oxidative polymerization and cross-linking of aniline on the surface of the base film, a selective separation layer can be formed on the surface of the polyaniline base film; the high temperature resistant nanofiltration membrane provided in this embodiment can retain a molecular weight between 150-1000Da, and has a high selectivity for Na 2 SO 4 The retention rate is above 90%, and the retention rate of the high temperature resistant nanofiltration membrane at 80°C is within 5% of the retention rate at room temperature, which shows that it has good temperature resistance. In addition, the high temperature resistant nanofiltration membrane does not use volatile organic solvents during preparation, and is environmentally friendly. DETAILED DESCRIPTION

[0040] The principles and features of the present invention are described below in conjunction with the embodiments, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. The present invention is described more specifically by way of example with reference to the embodiments in the following paragraphs. According to the following description and the claims, the advantages and features of the present invention will be more clearly described.

[0041] The present embodiment provides a method for preparing a high temperature resistant nanofiltration membrane, wherein the base membrane is soaked in an aniline oxidation prepolymer solution and a cross-linking agent solution for a period of time, taken out, and rinsed with pure water, and then the base membrane is placed at 80-100°C (any value of 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C and 120°C or a range corresponding to any two values) and heated for 5-15min (any value of 5min, 6min, 7min, 8min, 9min, 10min, 11min and 12min or a range corresponding to any two values) to obtain a high temperature resistant nanofiltration membrane;

[0042] Wherein, the base membrane is one of a polysulfone membrane, a polyimide membrane, and a meta-aramid membrane;

[0043] The base film is first soaked in the aniline oxidation prepolymer solution, taken out, rinsed with pure water and then soaked in the crosslinker solution, or the base film is first soaked in the crosslinker solution, taken out, rinsed with pure water and then soaked in the aniline oxidation prepolymer solution.

[0044] The preparation method of the base film in the above technical solution is as follows:

[0045] A polymer solution is prepared by using a polymer and an additive as solutes, wherein the polymer is one of polysulfone, polyimide and meta-aramid;

[0046] The polymerization solution is heated and allowed to stand for degassing;

[0047] The defoamed polymer solution is coated on the non-woven fabric and immersed in pure water for solidification to obtain a base film with the non-woven fabric as a support carrier;

[0048] The prepared basement membrane was placed in pure water for later use.

[0049] The method for preparing the base film in the above technical solution satisfies at least one of the following conditions:

[0050] a1: the additive is polyvinyl pyrrolidone, polyethylene glycol or lithium chloride;

[0051] b1: The non-woven fabric is a polyester non-woven fabric or a polypropylene non-woven fabric;

[0052] c1: the concentration of the polymer in the polymer solution is 12-22wt% (can be any value among 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt% and 22wt% or the corresponding range between any two values);

[0053] d1: the additive content in the polymer solution is 1-5wt% (can be any value among 1wt%, 2wt%, 3wt%, 4wt% and 5wt% or a range corresponding to any two values);

[0054] e1: the solvent of the polymer solution is at least one of N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone;

[0055] f1: The degassing temperature is 50-100℃ (it can be any value among 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ and 100℃ or the corresponding range between any two values).

[0056] The preparation method of the aniline oxidation prepolymer solution described in the above technical scheme is as follows:

[0057] Aniline substances and oxidants are used as solutes to prepare aniline oxidation prepolymerization liquid, and the aniline oxidation prepolymerization liquid is prepolymerized for a period of time, wherein the aniline substances are phenylenediamine and / or its derivatives.

[0058] The method for preparing the aniline oxidation prepolymer solution in the above technical solution satisfies at least one of the following conditions:

[0059] a2: the concentration of aniline substances in the aniline oxidation prepolymer solution is 0.01-2wt% (can be any value among 0.01wt%, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% and 2wt%, or the range corresponding to any two values);

[0060] b2: the concentration of the oxidant 1 in the aniline oxidation prepolymer solution is 0.01-0.4wt% (can be any value among 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt% and 0.4wt% or the range corresponding to any two values);

[0061] c2: the solvent in the aniline oxidation prepolymer solution is at least one of water, methanol, ethanol and propanol;

[0062] d2: Oxidant 1 is sodium peroxodisulfate, potassium persulfate or potassium permanganate;

[0063] e2: the duration of prepolymerization is 1-120 min (can be any value among 1 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 wt %, 95 min, 100 min, 105 min, 110 min, 115 min and 120 min, or the range corresponding to any two values);

[0064] f2: The phenylenediamine derivative includes at least one of p-phenylenediamine, m-phenylenediamine, p-phenylenediamine sulfonic acid and m-phenylenediamine sulfonic acid.

[0065] The preparation method of the cross-linking agent solution in the above technical solution is as follows:

[0066] A crosslinking agent solution is prepared by taking a crosslinking agent and a second oxidizing agent as solutes, wherein the crosslinking agent is catechol, pyrogallol, tannic acid, gallic acid, glutaraldehyde or 1,3-isophthalaldehyde.

[0067] The method for preparing the crosslinking agent solution in the above technical solution satisfies at least one of the following conditions:

[0068] a3: the concentration of the crosslinking agent in the crosslinking agent solution is 0.1-0.4 wt% (can be any value among 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt% and 0.4 wt% or a range corresponding to any two values);

[0069] b3: the solvent of the cross-linking agent solution is at least one of water, methanol, ethanol and propanol;

[0070] c3: Oxidant 2 is sodium periodate, potassium persulfate or hydrogen peroxide;

[0071] d3: The concentration of oxidant 2 in the cross-linking agent solution is 0-0.4wt% (it can be any value among 0wt%, 0.05wt%, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt% and 0.4wt% or the corresponding range between any two values).

[0072] In the above technical solution, the base film is immersed in the aniline oxidation prepolymer solution for 3-60 minutes (which can be any value among 3min, 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min and 60min, or a range corresponding to any two values); the base film is immersed in the cross-linking agent solution for 5-120 minutes (which can be any value among 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, 65min, 70min, 75min, 80min, 85min, 90wt%, 95min, 100min, 105min, 110min, 115min and 120min, or a range corresponding to any two values).

[0073] Example 1

[0074] 1. Preparation of base film:

[0075] By weight, 18 parts of polysulfone and 3 parts of polyvinyl pyrrolidone (additive) are dissolved in 79 parts of N, N-dimethylacetamide solvent to prepare a polymer solution with a polysulfone concentration of 18 wt% and an additive concentration of 3 wt%;

[0076] The polymer solution is heated and allowed to stand, and after sufficient degassing, the polymer solution is coated on a PET non-woven fabric using a scraping knife with a film thickness of 250 microns, and the non-woven fabric coated with the polymer is immersed in water for solidification, thereby completing the preparation of the base film;

[0077] The basement membrane was fixed on a glass plate with a hollow frame (8x12 cm) for later use.

[0078] 2. Preparation of Aniline Oxidation Prepolymer Solution

[0079] Take 12 parts of 1g / L m-phenylenediamine / ethanol solution by volume, and add 4 parts of 2wt% sodium periodate aqueous solution, and react for 1 hour before use.

[0080] 3. The cross-linking agent solution directly uses a 3g / L tannic acid / water solution.

[0081] 4. Preparation of high temperature resistant nanofiltration membrane

[0082] The base membrane was soaked in aniline oxidation prepolymer solution for 1 hour, then the base membrane was taken out, and the membrane surface was blown dry with a dust gun, and then the base membrane was soaked in a cross-linking agent solution to react for 15 minutes to obtain a high-temperature resistant nanofiltration membrane, and then the high-temperature resistant nanofiltration membrane was taken out and soaked in pure water.

[0083] 5. Testing

[0084] The separation performance of the prepared high temperature resistant nanofiltration membrane was tested on a cross flow device using a 0.3 g / L PEG200 aqueous solution as the test solution. When the feed temperature was 25°C, the retention rate of PEG200 was 95.6%, and the water flux of the membrane was 2.6 L / (m 2 ·h·bar), when the feed liquid temperature is 80℃, the retention rate of PEG200 is 92.2%, and the water flux of the membrane is 6.7L / (m 2 ·h·bar), when the feed liquid temperature increases from 25℃ to 80℃, the change in retention rate is less than 5%, indicating good temperature resistance.

[0085] Example 2

[0086] Same as Example 1, except that:

[0087] 3. The preparation method of the crosslinking agent solution in this embodiment is to add 1 part of 2 wt % sodium periodate aqueous solution to 12 parts of 1 g / L catechol / water solution by volume.

[0088] 5. Testing

[0089] When the feed liquid temperature is 25℃, the retention rate of PEG200 is 76% and the water flux of the membrane is 8L / (m 2 ·h·bar) When the feed liquid temperature is 80℃, the retention rate of PEG200 is 72.2% and the water flux of the membrane is 34.5L / (m 2 ·h·bar), when the temperature of the feed liquid increased from 25℃ to 80℃, the change in retention rate was less than 5%, indicating good temperature resistance.

[0090] Example 3

[0091] Same as Example 2, except that:

[0092] 2. The preparation method of aniline oxidation prepolymer solution in this embodiment is as follows: by volume, 0.5 parts of 2 wt% sodium periodate aqueous solution are added to 12 parts of 1 g / L m-phenylenediamine ethanol solution, and the mixture is reacted for 1 minute and then used.

[0093] 3. The preparation method of the crosslinking agent solution in this embodiment is to add 0.15 parts of 2 wt% sodium periodate aqueous solution to 12 parts of 3 g / L tannic acid ethanol solution by volume;

[0094] 4. Preparation of high temperature resistant nanofiltration membrane

[0095] The base membrane was soaked in aniline oxidation prepolymer solution for 30 minutes, then the base membrane was taken out, and the membrane surface was blown dry with a dust gun, and then the base membrane was soaked in aniline oxidation prepolymer solution for 30 minutes to obtain a high temperature resistant nanofiltration membrane, and then the high temperature resistant nanofiltration membrane was taken out and soaked in pure water.

[0096] 5. Testing

[0097] With a concentration of 1g / L Na 2 SO 4 The aqueous solution was used as the test solution to test the separation performance of the membrane in a cross-flow device. When the feed liquid temperature was 25°C, Na 2 SO 4 The rejection rate is 95.8%, and the water flux of the membrane is 10.5L / (m 2 ·h·bar) When the feed liquid temperature is 80℃, Na 2 SO 4 The rejection rate is 92.6%, and the water flux of the membrane is 17.5L / (m 2 ·h·bar), when the temperature of the feed liquid increased from 25℃ to 80℃, the change in retention rate was less than 5%, indicating good temperature resistance.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a high temperature resistant nanofiltration membrane, characterized in that: The base membrane is soaked in aniline oxidation prepolymer solution and cross-linking agent solution for a period of time, then taken out and rinsed with pure water, and then the base membrane is heated at 80-100°C for 5-15 minutes to obtain a high temperature resistant nanofiltration membrane; Wherein, the base membrane is one of a polysulfone membrane, a polyimide membrane, and a meta-aramid membrane; The base film is first soaked in the aniline oxidation prepolymer solution, taken out, rinsed with pure water and then soaked in the crosslinker solution, or the base film is first soaked in the crosslinker solution, taken out, rinsed with pure water and then soaked in the aniline oxidation prepolymer solution.

2. The method for preparing a high temperature resistant nanofiltration membrane according to claim 1, characterized in that: The preparation method of the basement membrane is specifically as follows: A polymer solution is prepared by using a polymer and an additive as solutes, wherein the polymer is one of polysulfone, polyimide and meta-aramid; The polymerization solution is heated and allowed to stand for degassing; The defoamed polymer solution is coated on the non-woven fabric and immersed in pure water for solidification to obtain a base film with the non-woven fabric as a support carrier; The prepared basement membrane was placed in pure water for later use.

3. The method for preparing a high temperature resistant nanofiltration membrane according to claim 2, characterized in that: The preparation method of the base film satisfies at least one of the following conditions: a1: the additive is polyvinyl pyrrolidone, polyethylene glycol or lithium chloride; b1: The non-woven fabric is a polyester non-woven fabric or a polypropylene non-woven fabric; c1: the concentration of the polymer in the polymer solution is 12-22 wt%; d1: the additive content in the polymer solution is 1-5wt%; e1: the solvent of the polymer solution is at least one of N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; f1: The degassing temperature is 50-100℃.

4. The method for preparing a high temperature resistant nanofiltration membrane according to claim 2, characterized in that: The preparation method of the aniline oxidation prepolymer solution is as follows: Aniline substances and oxidants are used as solutes to prepare aniline oxidation prepolymerization liquid, and the aniline oxidation prepolymerization liquid is prepolymerized for a period of time, wherein the aniline substances are phenylenediamine and / or its derivatives.

5. The method for preparing a high temperature resistant nanofiltration membrane according to claim 4, characterized in that: The preparation method of the aniline oxidation prepolymer solution satisfies at least one of the following conditions: a2: the concentration of aniline substances in the aniline oxidation prepolymer solution is 0.01-2wt%; b2: the concentration of the oxidant 1 in the aniline oxidation prepolymer solution is 0.01-0.4wt%; c2: the solvent of the aniline oxidation prepolymer solution is at least one of water, methanol, ethanol and propanol; d2: Oxidant 1 is sodium peroxodisulfate, potassium persulfate or potassium permanganate; e2: The duration of prepolymerization is 1-120 min; f2: Phenylenediamine derivatives include p-phenylenediamine, m-phenylenediamine, p-phenylenediamine sulfonic acid, and m-phenylenediamine sulfonic acid.

6. The method for preparing a high temperature resistant nanofiltration membrane according to claim 4, characterized in that: The preparation method of the cross-linking agent solution is as follows: A crosslinking agent solution is prepared by taking a crosslinking agent and a second oxidizing agent as solutes, wherein the crosslinking agent is catechol, pyrogallol, tannic acid, gallic acid, glutaraldehyde or 1,3-isophthalaldehyde.

7. The method for preparing a high temperature resistant nanofiltration membrane according to claim 6, characterized in that: The preparation method of the cross-linking agent solution satisfies at least one of the following conditions: a3: the concentration of the crosslinking agent in the crosslinking agent solution is 0.1-2wt%; b3: the solvent of the cross-linking agent solution is at least one of water, methanol, ethanol and propanol; c3: Oxidant 2 is sodium periodate, potassium persulfate or hydrogen peroxide; d3: The concentration of the second oxidant in the cross-linking agent solution is 0-0.4 wt%.

8. The method for preparing a high temperature resistant nanofiltration membrane according to claim 1, characterized in that: The base film is immersed in the aniline oxidation prepolymer solution for 3-60 minutes; the base film is immersed in the cross-linking agent solution for 5-120 minutes.

9. A high temperature resistant nanofiltration membrane, characterized in that: The method is prepared according to any one of claims 1 to 8.

10. An application of the high temperature resistant nanofiltration membrane according to claim 9, characterized in that: Used in condensate desalination, high-temperature material separation or filtration processes that require regular high-temperature hot water disinfection.