A high-temperature-resistant reverse osmosis composite membrane containing a covalent organic framework interlayer and a preparation method thereof

Abstract

This invention discloses a high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer and its preparation method. First, a covalent organic framework interlayer is constructed on a porous polyethersulfone substrate using a unidirectional diffusion method. After cross-linking and pore reduction with a small-molecule diamine, a certain concentration of m-phenylenediamine aqueous solution is coated onto its surface. After removing excess aqueous solution, interfacial polymerization is performed with an oil phase solution containing trimesoyl chloride, thereby obtaining the high-temperature resistant reverse osmosis composite membrane containing the covalent organic framework interlayer. This invention innovatively incorporates pore reduction COF... Tp‑Pa The introduction of a reverse osmosis composite membrane into the intermediate layer not only increases the transport channels for water molecules within the membrane and improves the wetting and diffusion of amine monomers during the interfacial polymerization process, but also enhances the adhesion between the composite membrane layers through covalent reactions, thereby simultaneously improving the membrane's water permeability, the regularity of the separation layer structure, and the performance stability under high temperature conditions.

Description

Technical Field

[0001] This invention relates to a high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer and its preparation method. Background Technology

[0002] Reverse osmosis technology is commonly used in industries such as textile printing and dyeing, and petrochemicals for the separation, concentration, or resource recovery of high-temperature feed solutions / wastewater. However, currently available commercially available polyamide reverse osmosis composite membrane elements operate at temperatures below 45°C, making them unsuitable for directly treating high-temperature feed solutions and wastewater. This severely limits the application of reverse osmosis technology under high-temperature conditions. Research indicates that the polymer structure of the polyamide separation layer and porous support layer significantly impacts the temperature resistance of the reverse osmosis membrane. When the feed solution temperature exceeds the polymer's glass transition temperature (T0), the membrane's resistance increases. g ), melting point (T) m High temperatures and heat distortion temperatures (HDTs) can cause membrane deformation (such as swelling) and pore collapse, significantly reducing the membrane's pressure resistance and separation performance, as well as the salt rejection rate. Therefore, there is an urgent need to develop high-temperature resistant reverse osmosis composite membranes to promote the separation and concentration of high-temperature feed solutions using reverse osmosis technology.

[0003] In recent years, the academic and industrial communities have mainly improved the thermal stability of reverse osmosis composite membranes by improving the structure of the membrane matrix material and strengthening the interaction between the support layer and the separation layer. For example, using high-temperature resistant poly(naphthyl biphenyl) polyarylene ether amide (Journal of Membrane Science, 2006, 279(1-2):238-245), poly(naphthyl biphenyl) polyarylene ether sulfone ketone (Journal of Membrane Science, 2005, 246(2):121-126), or poly(pyromellitic dianhydride-co-4,4′-diaminodiphenyl ether (Journal of Membrane Science, 2010, 363, 140-148) to prepare porous supported membranes, and then preparing polyamide composite reverse osmosis membranes through interfacial polymerization, the desalination rate can be maintained at around 98% at 75-95℃, and the flux can reach over 31 LMH. Suez has launched the Duratherm series of high-temperature resistant reverse osmosis composite membranes with a special intermediate layer, which can withstand 90℃ hot water disinfection and can operate for a long time at 50℃, especially Duratherm. EXL membrane elements achieve a desalination rate of up to 98.5% and a flux of approximately 34 LMH at 80°C. However, the research and development of temperature-resistant reverse osmosis membranes still faces some challenges. For example, the synthesis of naphthalene-biphenyl polyether materials is complex and costly, making industrialization difficult. Duratherm series membrane elements are expensive, and their operating pressure cannot exceed 35 bar at temperatures above 70°C, with lower desalination rates and water flux compared to conventional reverse osmosis membranes. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing reverse osmosis composite membranes in terms of temperature resistance and to provide a method for preparing a high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer. The high-temperature resistant reverse osmosis composite membrane is prepared by constructing a covalent organic framework interlayer in situ on a polyethersulfone substrate membrane using a diffusion cell via unidirectional diffusion, followed by crosslinking with small-molecule polyamines to create pores in the interlayer. Subsequently, an interfacial polymerization reaction is performed on the surface of the pore-filled covalent organic framework interlayer using an aqueous solution containing m-phenylenediamine monomer and an oil solution containing trimesoyl chloride monomer to obtain the high-temperature resistant reverse osmosis composite membrane. Introducing the pore-filled covalent organic framework interlayer into the reverse osmosis composite membrane increases the transport channels for water molecules within the membrane, improves the wetting and diffusion of amine monomers during the interfacial polymerization process, and enhances the adhesion between the composite membrane layers through covalent reactions. This simultaneously improves the water permeability, separation layer structure regularity, and performance stability of the prepared reverse osmosis membrane under high-temperature conditions.

[0005] This invention proposes to construct a covalent organic framework intermediate layer in situ on a polyethersulfone substrate membrane, and then to prepare a high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework intermediate layer by in situ pore reduction with small molecule polyamine.

[0006] A method for preparing a high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer includes the following steps:

[0007] (1) Dissolve polyethersulfone powder in N,N-dimethylformamide and stir continuously for 12-24 h to obtain a uniform casting solution. After standing for 12-24 h, coat the standing casting solution onto a non-woven fabric and place it in a deionized water coagulation bath for phase separation. The phase separation time is 10-300 seconds to obtain a polyethersulfone porous substrate membrane.

[0008] (2) Fix the polyethersulfone substrate obtained in step (1) to the center of the diffusion cell, then add a trimethylol pyrogallol oil phase solution to the diffusion groove facing the smooth side of the polyethersulfone substrate, and add an aqueous solution of p-phenylenediamine containing acetic acid to the diffusion groove facing the non-woven fabric side of the polyethersulfone substrate. After sealing and standing for 2 to 5 days, take out the film, and then wash the residual liquid with ethanol and water to obtain a polyethersulfone substrate containing a covalent organic framework intermediate layer.

[0009] (3) The polyethersulfone substrate with a covalent organic framework intermediate layer obtained in step (2) is immersed in a polyamine solution for cross-linking and pore reduction. The cross-linking time is 3 to 24 hours to obtain a polyethersulfone substrate with a pore-reducing COF intermediate layer.

[0010] (4) Fix the polyethersulfone substrate membrane containing the pore-tight COF interlayer obtained in step (3) to the center of the diffusion cell. Then, add the m-phenylenediamine aqueous solution to the diffusion tank facing the smooth side of the substrate membrane. After keeping the membrane surface immersed, pour out the aqueous solution in the tank and place the diffusion tank in a ventilated place to allow the membrane surface to air dry. Then, add the trimesoyl chloride oil solution to the diffusion tank facing the smooth side of the substrate membrane. After keeping the membrane surface in contact, pour out the oil solution in the tank again and place the diffusion tank in a ventilated place to allow the membrane surface to air dry. Finally, place the membrane in an oven for heat treatment. The heat treatment temperature is 50-100℃ and the heat treatment time is 3-20 minutes. The high-temperature resistant reverse osmosis composite membrane containing the pore-tight COF interlayer is thus obtained, which is the high-temperature resistant reverse osmosis composite membrane containing the covalent organic framework interlayer.

[0011] A further preferred embodiment is a method for preparing a high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer, comprising the following steps:

[0012] (1) First, a polyethersulfone substrate membrane was prepared using a solvent-inducible phase inversion method. 16-20 wt% of polyethersulfone powder was dissolved in N,N-dimethylformamide solvent using a magnetic stirrer and stirred continuously at room temperature for 12-24 h to obtain a uniform casting solution. After standing at room temperature for 12-24 h, the prepared casting solution was coated onto a nonwoven fabric and placed in a deionized water coagulation bath for phase separation. The phase separation time was 10-300 seconds, thereby obtaining a porous polyethersulfone substrate membrane.

[0013] (2) Fix the polyethersulfone substrate obtained in step (1) to the center of the diffusion cell. Then, add 2-20 ppm of trimethylolpropionic acid pyrogallol oil phase solution to the diffusion cell facing the smooth side of the membrane, and add 2-20 ppm of p-phenylenediamine aqueous solution (containing a certain amount of acetic acid as a catalyst) to the diffusion cell facing the nonwoven fabric side. After sealing and standing for three days, remove the membrane and wash off the residual liquid with ethanol and water, thereby obtaining a membrane containing a covalent organic framework (COF). Tp-Pa The middle layer is a polyethersulfone base film, which is then stored in deionized water for later use.

[0014] (3) The polyethersulfone substrate with COF interlayer obtained in step (2) is immersed in a small molecule polyamine solution of 1 to 3000 ppm for cross-linking and pore reduction, and the cross-linking time is 3 to 24 h, thereby obtaining a polyethersulfone substrate with COF interlayer with pore reduction.

[0015] (4) Fix the polyethersulfone substrate membrane containing the pore-shrink COF interlayer obtained in step (3) to the center of the diffusion tank. Then, add 1-3 wt% of m-phenylenediamine (MPD) aqueous solution to the diffusion tank facing the smooth side of the substrate membrane. Keep the membrane surface immersed for 1-5 minutes, then pour out the aqueous solution in the tank and place the diffusion tank in a ventilated place to allow the membrane surface to air dry. Then, add 0.1-0.5 wt% of trimesoyl chloride (TMC) oil solution to the diffusion tank facing the smooth side of the substrate membrane. Keep the membrane surface in contact for 30-120 seconds, then pour out the oil solution in the tank again and place the diffusion tank in a ventilated place to allow the membrane surface to air dry. Finally, place the membrane in an oven for heat treatment at a temperature of 80-110°C for 3-10 minutes. This yields a high-temperature resistant reverse osmosis composite membrane containing the pore-shrink COF interlayer.

[0016] Further, in step (2), the preparation of the trimethylformaldehyde phloroglucinol oil phase solution specifically includes: dissolving trimethylformaldehyde phloroglucinol in Isopar G and ultrasonically preparing the oil phase solution, wherein the ratio of trimethylformaldehyde phloroglucinol to Isopar G is 0.2 mg to 0.6 mg: 50 to 150 ml, and most preferably, the mass of trimethylformaldehyde phloroglucinol to p-phenylenediamine is 4 ppm. The preparation of the p-phenylenediamine aqueous solution containing acetic acid specifically includes: dissolving p-phenylenediamine or p-phenylenediamine sulfonate and glacial acetic acid in water and ultrasonically preparing the aqueous phase solution, wherein the ratio of p-phenylenediamine or p-phenylenediamine sulfonate, glacial acetic acid, and water is 0.2 to 0.6 mg: 40 to 80 μl: 50 to 150 ml.

[0017] Furthermore, in step (3), the polyamine monomer is any one or more of the following, such as m-phenylenediamine, p-phenylenediamine, pyromellitic triamine, 5-methyl-m-phenylenediamine, 2-hydroxy-propanediamine, and ethylenediamine, mixed in any proportion.

[0018] Furthermore, in step (3), the concentration of the polyamine monomer is 800-1200 mg / L (most preferably 1000 mg / L).

[0019] Further, in step (4), the concentration of the intermediate-phenylenediamine monomer in the aqueous phase solution of m-phenylenediamine is 1-3 wt%, and the aqueous phase solution of m-phenylenediamine also contains 0.1-0.3 wt% sodium dodecyl sulfonate, 3-5 wt% camphor sulfonic acid, and 1-3 wt% triethylamine. More preferably, the concentration of the intermediate-phenylenediamine monomer in the aqueous phase solution is 1-3 wt%, and it also contains 0.15 wt% sodium dodecyl sulfonate, 4 wt% camphor sulfonic acid, and 2 wt% triethylamine.

[0020] Furthermore, in step (4), the soaking time in the aqueous phase is 1 to 5 minutes.

[0021] Furthermore, in step (4), the solvent for the oil phase solution is Isopar G, the concentration of trimesoyl chloride monomer is 0.1-0.3 wt%, and the contact time is 30-120 seconds.

[0022] Furthermore, in step (4), the heat treatment temperature is 80-110°C and the heat treatment time is 3-10 minutes.

[0023] A high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer prepared by the above-described method. Compared with the prior art, the advantages of this invention are:

[0024] This invention first employs a one-way diffusion method to construct a covalent organic framework intermediate layer (COF) on a porous polyethersulfone substrate. Tp-Pa After crosslinking and shrinking pores with a small molecule diamine, a certain concentration of m-phenylenediamine aqueous solution is coated onto its surface. After removing excess aqueous solution, interfacial polymerization is performed with an oil-phase solution containing trimesoyl chloride, thereby obtaining a high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer. The COF-containing membrane prepared in this invention... Tp-Pa Compared to conventional aromatic polyamide reverse osmosis composite membranes, the water flux and desalination rate of the intermediate layer reverse osmosis composite membrane are simultaneously improved, while maintaining excellent performance stability under high temperature conditions.

[0025] This invention utilizes a one-sided diffusion method to grow a covalent organic framework interlayer (COF) in situ on the surface of a polysulfone porous substrate via an interfacial Schiff base reaction of pyrogallol (Tp) and p-phenylenediamine (Pa). Tp-Pa The process involves in-situ crosslinking with small-molecule polyamines to create pores, followed by interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on its surface to prepare a high-temperature resistant reverse osmosis composite membrane with a covalent organic framework interlayer. The pore-reducing COF... Tp-Pa The intermediate layer not only increases the transport channels for water molecules within the membrane and improves the wetting and diffusion of phenylenediamine monomers during the interfacial polymerization process, but also enhances the adhesion between the composite membrane layers through the covalent reaction of residual amine groups on small molecule amines after pore shrinkage with trimesoyl chloride (TMC). This results in a simultaneous improvement in the membrane's water flux, separation layer structure regularity, desalination rate, interlayer adhesion, and performance stability under high temperature conditions. Attached Figure Description

[0026] Figure 1 This is a transmission electron microscope image of the covalent organic framework described in this invention;

[0027] Figure 2 These are transmission electron microscope (TEM) cross-sectional images, atomic force maps, and scanning electron microscope (SEM) images of the reverse osmosis membranes in the four cases described in this invention. Detailed Implementation

[0028] This invention first uses a one-sided diffusion method to prepare a covalent organic framework interlayer in situ on a polyethersulfone porous substrate membrane. Then, it is placed in a small molecule polyamine solution for cross-linking and pore reduction, thereby obtaining a polyethersulfone supported substrate membrane containing a covalent organic framework. Subsequently, a high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer is obtained by interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on its surface. Tp-Pa The introduction of this technology simultaneously improves the water flux, separation layer structure regularity, desalination rate, interlayer adhesion, and performance stability of the reverse osmosis composite membrane under high-temperature conditions. The following detailed description, in conjunction with specific embodiments, further clarifies the invention. However, the scope and content of this patent are not limited to the following embodiments; any variations that do not depart from the scope and content of this invention should be included within its technical scope.

[0029] Example 1:

[0030] Step ① – Preparation of polyethersulfone substrate film

[0031] A polyethersulfone (PES) substrate was prepared using a solvent-free phase inversion method. 18 wt% PES powder was dissolved in N,N-dimethylformamide solvent using a magnetic stirrer and continuously stirred at 25°C for 24 h to obtain a homogeneous casting solution. After standing at 25°C for 24 h, the prepared casting solution was coated onto a 200 μm separation layer on a nonwoven fabric and placed in deionized water for phase separation, with a separation time of 60 seconds.

[0032] Step ② – Preparation of the intermediate layer of the covalent organic framework

[0033] The polyethersulfone substrate membrane obtained in step ① was fixed in the center of the diffusion cell. Then, 4 ppm of a trimethylolpropionic acid (Tp) oil phase solution was added to the diffusion cell facing the smooth side of the membrane (the oil phase solution was prepared by first dissolving 0.4 mg of Tp in 100 ml of Isopar G and sonicating for 5 minutes at room temperature (25°C)). 4 ppm of a p-phenylenediamine (Pa) aqueous solution was added to the diffusion cell facing the nonwoven fabric side (the aqueous phase solution was prepared by first dissolving 0.4 mg of p-phenylenediamine or o-phenylenediamine sulfonate in 60 μl of glacial acetic acid and then sonicating for 5 minutes in 100 ml of deionized water). After sealing and standing for three days, the membrane was removed, and the residual liquid was washed with ethanol and water, thus obtaining a covalent organic framework (COF) containing a covalent organic framework (COF). Tp-Pa The intermediate polyethersulfone substrate was then stored in deionized water for three days after sealing. Afterward, the residue was washed with ethanol and water, and stored in deionized water until use. The in-situ grown COF... Tp-Pa Crystal lattice Figure 1 As shown.

[0034] Step ③ – Crosslinking and Pore Reduction in the Intermediate Layer of the Covalent Organic Framework

[0035] Prepare a 1000 ppm solution of 2-hydroxy-propanediamine (DAP), and then prepare the COF-containing... Tp-Pa The polyethersulfone substrate of the intermediate layer is immersed in the solution for 24 hours. After cross-linking and pore reduction are completed, the membrane is removed and the residual liquid on the membrane surface is washed with ethanol and water in turn. Finally, it is stored in deionized water for later use.

[0036] Step 4 – Preparation of reverse osmosis composite membrane based on covalent organic framework intermediate layer modification

[0037] The COF containing shrinkage cavities obtained in step ③ Tp-Pa After the polyethersulfone substrate membrane of the intermediate layer was air-dried, it was fixed in the middle of the diffusion tank. Then, an aqueous solution (containing 2 wt% m-phenylenediamine, 0.15 wt% sodium dodecyl sulfonate, 4 wt% ceramide, and 2 wt% triethylamine) was added to the diffusion tank facing the smooth side of the substrate membrane, and the substrate membrane was immersed for 2 minutes on one side. After immersion, the aqueous solution in the tank was removed, and the membrane was air-dried in the air. Subsequently, an Isopar G oil phase solution containing 0.15 wt% trimesoyl chloride was added to the diffusion tank facing the smooth side of the substrate membrane, and the substrate membrane was brought into contact for 60 seconds to carry out the interfacial polymerization reaction. After the reaction, the oil phase solution in the tank was removed, and the membrane was air-dried again at room temperature. Finally, the membrane was heat-treated in a 90°C oven for 5 minutes, thereby obtaining a reverse osmosis composite membrane with a covalent organic framework intermediate layer. The performance data of the obtained membrane are listed in Tables 1-5.

[0038] Example 2:

[0039] The 1000 ppm 2-hydroxy-propanediamine solution in step ③ was replaced with a 1000 ppm ethylenediamine solution, and the other operations were the same as in Example 1. The performance data of the obtained membrane are listed in Table 1.

[0040] Example 3:

[0041] Step ③ is omitted, and the other operations are the same as in Example 1. The performance data of the obtained membrane are listed in Tables 1 to 5.

[0042] Example 4:

[0043] The standing time in step ② was changed from 3 days to 2 days, and other operations were the same as in Example 1. The performance data of the obtained membrane are listed in Table 1.

[0044] Example 5:

[0045] In step ②, the standing time of 3 days was changed to 2 days, and in step ③, the 1000 ppm 2-hydroxy-propanediamine solution was changed to 1000 ppm ethylenediamine solution. Other operations were the same as in Example 1. The performance data of the obtained membrane are listed in Table 1.

[0046] Example 6:

[0047] In step ②, the standing time of 3 days was changed to 2 days, and step ③ was omitted. Other operations were the same as in Example 1. The performance data of the obtained membrane are listed in Table 1.

[0048] Comparative Example 1:

[0049] Steps ② and ③ are omitted, and other operations are the same as in Example 1. The performance data of the obtained membrane are listed in Tables 1 to 5.

[0050] The atomic force and electron microscopy images of the reverse osmosis composite membrane containing a covalent organic framework interlayer, as shown in Examples 1, 2, 3 and Comparative Example 1, are as follows. Figure 2 As shown in the figures (a is Comparative Example 1, b is Example 3, c is Example 1, d is Example 2), the membrane separation performance was tested using a high-pressure composite membrane evaluation instrument. Before testing, the membrane was pre-pressurized with pure water for 1 hour. Then, 2000 ppm sodium chloride solution was used to replace the pure water, and the membrane separation performance was tested at 1.55 MPa. The test temperatures were 25℃, 45℃, and 70℃, and the test results are shown in Tables 1-2, 3, and 4, respectively. Finally, the separation performance stability of the three reverse osmosis membranes was compared and tested at 70℃ for 6 hours of continuous operation, and the test results are shown in Table 5.

[0051] Table 1: Separation performance of Examples 1-6 and Comparative Example 1 at 25°C

[0052]

[0053] Test conditions: 25℃, 1.55MPa, 2000ppm sodium chloride feed solution

[0054] Table 2: Separation performance of Examples 1, 3 and Comparative Example 1 at 25°C

[0055]

[0056] Test conditions: 25℃, 1.55MPa, 2000ppm sodium chloride feed solution

[0057] Table 3: Separation performance of Examples 1, 3 and Comparative Example 1 at 45°C

[0058]

[0059] Test conditions: 45℃, 1.55MPa, 2000ppm sodium chloride feed solution

[0060] Table 4: Separation performance of Examples 1, 3 and Comparative Example 1 at 70°C

[0061]

[0062] Test conditions: 70℃, 1.55MPa, 2000ppm sodium chloride feed solution

[0063] Table 5: Separation performance of Examples 1, 3 and Comparative Example 1 after continuous operation at 70°C for 6 hours

[0064]

[0065] Test conditions: 70℃, 1.55MPa, 2000ppm sodium chloride feed solution

[0066] Based on the above results, compared with conventional polyamide reverse osmosis composite membranes (Comparative Example 1), the reverse osmosis composite membranes with the introduction of a pore-tight covalent organic framework interlayer show improved desalination rate and water flux. In particular, the reverse osmosis composite membrane with a DAP pore-tight covalent organic framework interlayer (Example 1) exhibits the best separation performance, with a desalination rate consistently above 99.4% and a flux as high as 50.0 L·m⁻¹ between 25 and 70°C. -2 ·h -1 The above-mentioned performance maintained high stability throughout 6 hours of continuous operation at 70℃, thus demonstrating promising potential for stable application in the separation and concentration of high-temperature liquids. Figure 2 Atomic force and scanning electron microscopy revealed that after the covalent organic framework intermediate layer was treated with small molecule amine to reduce pore size, the separation layer surface of the reverse osmosis composite membrane became rougher, denser, and thicker, thereby simultaneously improving the membrane's water flux, desalination rate, and temperature resistance.

[0067] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a high temperature resistant reverse osmosis composite membrane containing a covalent organic framework interlayer, characterized in that, Includes the following steps: (1) Dissolve polyethersulfone powder in N,N-dimethylformamide and stir continuously for 12-24 hours to obtain a uniform casting solution; After standing for 12 to 24 hours, the standing casting solution is scraped onto a nonwoven fabric and placed in a deionized water coagulation bath for phase separation. The phase separation time is 10 to 300 seconds to obtain a polyethersulfone porous bottom membrane. (2) Fix the polyethersulfone substrate obtained in step (1) to the center of the diffusion cell, then add a trimethylol pyrogallol oil phase solution to the diffusion groove facing the smooth side of the polyethersulfone substrate, and add an aqueous solution of p-phenylenediamine containing acetic acid to the diffusion groove facing the non-woven fabric side of the polyethersulfone substrate. After sealing and standing for 2 to 5 days, take out the film, and then wash the residual liquid with ethanol and water to obtain a polyethersulfone substrate containing a covalent organic framework intermediate layer. (3) The polyethersulfone substrate with a covalent organic framework intermediate layer obtained in step (2) is immersed in a polyamine solution for cross-linking and pore reduction. The cross-linking time is 3 to 24 hours to obtain a polyethersulfone substrate with a pore-reducing COF intermediate layer. (4) Fix the polyethersulfone substrate membrane containing the pore-tight COF interlayer obtained in step (3) to the center of the diffusion cell. Then, add the m-phenylenediamine aqueous solution to the diffusion tank facing the smooth side of the substrate membrane. After keeping the membrane surface immersed, pour out the aqueous solution in the tank and place the diffusion tank in a ventilated place to allow the membrane surface to air dry. Then, add the trimesoyl chloride oil solution to the diffusion tank facing the smooth side of the substrate membrane. After keeping the membrane surface in contact, pour out the oil solution in the tank again and place the diffusion tank in a ventilated place to allow the membrane surface to air dry. Finally, place the membrane in an oven for heat treatment. The heat treatment temperature is 50-100℃ and the heat treatment time is 3-20 minutes. The high-temperature resistant reverse osmosis composite membrane containing the pore-tight COF interlayer is thus obtained, which is the high-temperature resistant reverse osmosis composite membrane containing the covalent organic framework interlayer.

2. The production method according to claim 1, characterized by: In step (2), the preparation of the trimethylol phenyl hydroxyl oil phase solution specifically includes: dissolving trimethylol phenyl hydroxyl in Isopar G and ultrasonically preparing the oil phase solution, wherein the ratio of the amount of trimethylol phenyl hydroxyl to Isopar G is 0.2 mg to 0.6 mg: 50 to 150 ml.

3. The preparation method according to claim 1, characterized in that: In step (2), the preparation of the aqueous solution of p-phenylenediamine containing acetic acid specifically includes: dissolving p-phenylenediamine or p-phenylenediamine sulfonate in water and ultrasonically preparing an aqueous solution, wherein the ratio of p-phenylenediamine or p-phenylenediamine sulfonate, glacial acetic acid and water is 0.2-0.6 mg: 40-80 μl: 50-150 ml.

4. The preparation method according to claim 1, characterized in that: In step (3), the polyamine is any one or a mixture of m-phenylenediamine, p-phenylenediamine, pyromellitic triamine, 5-methyl-m-phenylenediamine, 2-hydroxy-propanediamine, and ethylenediamine.

5. The preparation method according to claim 1, characterized in that: In step (3), the concentration of polyamine in the polyamine solution is 800-1200 mg / L.

6. The preparation method according to claim 1, characterized in that: In step (4), the concentration of the intermediate phenylenediamine monomer in the aqueous phase solution of m-phenylenediamine is 1-3 wt%, and the aqueous phase solution of m-phenylenediamine also contains 0.1-0.3 wt% sodium dodecyl sulfonate, 3-5 wt% camphor sulfonic acid, and 1-3 wt% triethylamine.

7. The preparation method according to claim 1, characterized in that: In step (4), the aqueous solution of m-phenylenediamine is added to the diffusion tank facing the smooth side of the bottom film, and the film surface is kept immersed for 1 to 5 minutes.

8. The preparation method according to claim 1, characterized in that: In step (4), the solvent for the pyromellitic chloride oil phase solution is Isopar G, and the concentration of pyromellitic chloride in the pyromellitic chloride oil phase solution is 0.1-0.3 wt%. Add the pyromellitic methyl chloride oil phase solution to the diffusion tank facing the smooth side of the substrate film and maintain contact with the film surface for 10–120 seconds.

9. The preparation method according to claim 1, characterized in that: In step (4), the heat treatment temperature is 80-110℃ and the heat treatment time is 3-10 minutes.

10. A high-temperature resistant reverse osmosis composite membrane containing a covalent organic framework intermediate layer, prepared by the preparation method according to any one of claims 1-9.

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