High-temperature-resistant reverse osmosis membrane and preparation process thereof

Abstract

The application discloses a high-temperature-resistant reverse osmosis membrane and a preparation process thereof, relates to the field of membrane separation technology, and comprises a non-woven fabric layer, a support layer and a functional membrane layer. The non-woven fabric layer is a plasma pretreated non-woven fabric. The support layer is obtained by solidifying a support casting solution on the plasma pretreated non-woven fabric. The functional membrane layer is a polyamide layer doped with functional fillers. The raw material of the support casting solution comprises 12-21% of sulfonated poly (arylene ether ketone sulfone) copolymer, 3-7% of fluorinated titanium dioxide / metal organic framework modified graphite phase carbon nitride, 70-84% of N,N-dimethylformamide and 1-2% of a porogen according to mass percentage. The reverse osmosis membrane has excellent high-temperature resistance and hydrophilicity.

Description

Technical Field

[0001] This application relates to the field of membrane separation technology, and in particular to a high-temperature resistant reverse osmosis membrane and its preparation process. Background Technology

[0002] With the rapid development of China's chemical industry and the continuous advancement of urbanization, cities' already scarce water resources face even more severe pollution challenges. Chemical wastewater, in particular, is complex in composition and high in pollutant concentration, making it an extremely difficult type of wastewater to treat and recycle. If chemical wastewater is discharged indiscriminately, it will cause irreversible pollution to lakes, rivers, and soil, seriously threatening the ecological environment and human health. To address water scarcity and pollution problems, researchers have developed various advanced water treatment technologies. Among these technologies, reverse osmosis membrane separation technology stands out due to its significant advantages such as small footprint, simple operation, low energy consumption, and low cost, and is widely used in seawater desalination, drinking water production, and industrial wastewater treatment. Reverse osmosis technology is a membrane separation technology driven by pressure difference. Its core principle is to use a semi-permeable membrane, applying pressure higher than the osmotic pressure of a salt solution, to separate water molecules from salts and other dissolved impurities through the reverse osmosis membrane.

[0003] Currently, widely used composite reverse osmosis membranes typically operate only at temperatures below 50°C, significantly limiting their widespread application in industrial sectors. For example, in the dyeing and printing process of the textile industry, wastewater effluent temperatures are often high due to process requirements. In such cases, traditional reverse osmosis membranes require prior cooling of the wastewater before subsequent filtration, increasing equipment investment and operating costs while reducing overall treatment efficiency. High-temperature resistant reverse osmosis membranes, however, can directly filter and separate dyeing and printing wastewater at high temperatures, eliminating the need for additional cooling. This not only saves on equipment investment and energy consumption but also increases the solubility of solutes in the wastewater at high temperatures. Furthermore, high-temperature filtration accelerates water molecule movement, effectively improving membrane permeability and reducing contaminant adhesion to the membrane surface, thus minimizing fouling and clogging and extending membrane lifespan. Therefore, the development and application of high-temperature resistant reverse osmosis membranes are of great significance for the treatment of chemical wastewater. Summary of the Invention

[0004] In order to provide a high-temperature resistant reverse osmosis membrane, this application provides a high-temperature resistant reverse osmosis membrane and its preparation process.

[0005] This application provides a high-temperature resistant reverse osmosis membrane, which adopts the following technical solution:

[0006] A high-temperature resistant reverse osmosis membrane includes a nonwoven fabric layer, a support layer, and a functional membrane layer; the nonwoven fabric layer is a plasma-pretreated nonwoven fabric; the support layer is obtained by curing a support casting solution on the plasma-pretreated nonwoven fabric; the functional membrane layer is a polyamide layer doped with functional fillers.

[0007] The raw materials of the support casting solution include, by mass percentage, 12-21% sulfonated polyaryletherketone sulfone copolymer, 3-7% fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride, 70-84% N,N-dimethylformamide, and 1-2% pore-forming agent.

[0008] Preferably, the polyamide layer raw material doped with functional filler includes component A and component B; component A includes, by mass percentage, 5-10% fatty amine, 0.01-0.03% fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride, 0.04-0.06% 3-amino-1,2-propanediol, and the balance being water; component B includes, by mass percentage, 5-10% fatty acyl chloride, and the balance being organic solvent.

[0009] Preferably, the sulfonated polyarylether ketone sulfone copolymer is prepared from the following raw materials in parts by weight: 6.4-9.6 parts bisphenol A, 6-9 parts 4,4'-difluorobenzophenone, 6-9 parts 3,3'-disulfonated-4,4'-dichlorodiphenyl sulfone, 2.8-4.2 parts 4-carboxyphenylhydroquinone, 16.6-24.9 parts anhydrous potassium carbonate, 26-39 parts toluene, and 54.6-81.9 parts sulfolane.

[0010] Preferably, the method for preparing the sulfonated polyarylether ketone sulfone copolymer includes the following steps:

[0011] 6.4-9.6 parts of dried bisphenol A were mixed with 6-9 parts of 4,4'-difluorobenzophenone, 6-9 parts of 3,3'-disulfonated-4,4'-dichlorodiphenyl sulfone, 2.8-4.2 parts of 4-carboxyphenylhydroquinone, and 16.6-24.9 parts of anhydrous potassium carbonate and stirred until homogeneous. Then, 26-39 parts of toluene and 54.6-81.9 parts of sulfolane were added, and the mixture was heated to 40-50°C and stirred until homogeneous. The temperature was then raised to 125-145°C and refluxed for 4-6 hours. Toluene was removed by distillation at 125-145°C. The mixture was then heated to 185-195°C and stirred for 24-30 hours. After the reaction was completed, the mixture was removed from the water, washed under boiling conditions until the water was clear, and then dried to obtain the sulfonated polyarylether ketone sulfone copolymer.

[0012] Preferably, the fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride is prepared from the following raw materials in parts by weight: 0.03-0.06 parts of fluorinated titanium dioxide / metal-organic framework composite material, 48-96 parts of ethanol, and 0.5-1 parts of graphite phase carbon nitride.

[0013] Preferably, the fluorinated titanium dioxide / metal-organic framework composite material is prepared from the following raw materials in parts by weight: 0.2-0.3 parts fluorinated titanium dioxide, 60-90 parts water, 1-1.5 parts trimesic acid, and 0.25-0.3 parts tetrabutyl titanate;

[0014] The preparation method of the fluorinated titanium dioxide / metal-organic framework composite material includes the following steps:

[0015] Add 0.2-0.3 parts of fluorinated titanium dioxide to 40-60 parts of water, stir evenly, and then add 0.25-0.3 parts of tetrabutyl titanate. Stir the mixture in an oil bath at 70-80℃ for 3-4 hours. Separate the precipitate by centrifugation and wash to remove contaminants, obtaining a clean precipitate. Mix 0.25-0.3 parts of trimesic acid with the clean precipitate, add 20-30 parts of water, and sonicate for 15-25 minutes. Transfer the mixture to a hydrothermal reactor and heat in an oven at 150-180℃ for 8-10 hours. After the reaction is complete, cool to room temperature, separate the precipitate by centrifugation, wash the precipitate, and then dry it at 80-90℃ to obtain the fluorinated titanium dioxide / metal-organic framework composite material.

[0016] Preferably, the method for preparing the fluorinated titanium dioxide includes the following steps:

[0017] By weight, add 40-60 parts of water to 2.4-3.6 parts of titanium sulfate and stir until completely dissolved. Then, add 20.4-30.7 parts of hydrofluoric acid while stirring, and stir for 5-10 minutes after all the hydrofluoric acid has been added. Then, adjust the pH of the system to 8-9 and continue stirring for 15-20 minutes, and then let it stand for 20-25 minutes. Then, wash the sample by multiple water centrifugations and dry it at 75-85℃. Grind the dried material into powder, put it into a crucible, and heat treat it in a muffle furnace at 520-580℃ for 2-4 hours. After the heat treatment, let it cool naturally to the ambient temperature to obtain fluorinated titanium dioxide.

[0018] Preferably, the method for preparing the fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride includes the following steps:

[0019] 0.03-0.06 parts of fluorinated titanium dioxide / metal-organic framework composite material were added to 8-16 parts of ethanol and ultrasonically dispersed evenly. Then, 0.5-1 parts of graphitic carbon nitride were added to 40-80 parts of ethanol and ultrasonically dispersed evenly. Subsequently, the dispersion of fluorinated titanium dioxide / metal-organic framework composite material was added dropwise to the dispersion of graphitic carbon nitride. After ultrasonic dispersion for 60-80 min, the mixture was stirred at 60-65℃ for 5-7 h. The remaining ethanol was then evaporated by raising the temperature to obtain fluorinated titanium dioxide / metal-organic framework modified graphitic carbon nitride.

[0020] This application provides a process for preparing a high-temperature resistant reverse osmosis membrane, which adopts the following technical solution:

[0021] A process for preparing a high-temperature resistant reverse osmosis membrane includes the following steps:

[0022] S1. Soak the nonwoven fabric in isopropanol solution for 0.5-1h, rinse the isopropanol off the membrane surface with water, and dry it in an oven for later use; place the dried nonwoven fabric flat on the workbench for plasma treatment to obtain plasma pretreated nonwoven fabric.

[0023] S2. Mix 12-21% sulfonated polyarylether ketone sulfone copolymer, 3-7% fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride, 70-84% N,N-dimethylformamide, and 1-2% pore-forming agent by mass percentage, stir evenly, let stand for 1-3 hours, and then degas by ultrasonication for 10-30 minutes to obtain the support casting solution.

[0024] S3. The support casting solution obtained in S2 is applied to the plasma pretreated nonwoven fabric obtained in S1 with a thickness of 50-150μm; then evaporated at room temperature for 10-30s and then immersed in water at 15-25℃ to gel and solidify into a film; then dried in an oven at 50-70℃ for 5-8 hours to obtain the support layer.

[0025] S4. Mix 5-10% fatty amine, 0.01-0.03% fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride, 0.04-0.06% 3-amino-1,2-propanediol, and the balance being water by mass percentage to obtain component A; mix 5-10% fatty acyl chloride and the balance being organic solvent by mass percentage to obtain component B.

[0026] S5. The surface of the support layer obtained in S3 is first immersed in component A for 30-60s, and then left to stand at room temperature for 5-30s; then immersed in component B for 10-30s, and then left to react at room temperature for 8-12min. After that, it is placed in a drying oven and dried at 40-60℃ for 2-6h to obtain the functional membrane layer, thus obtaining the high-temperature resistant reverse osmosis membrane.

[0027] Preferably, the plasma treatment conditions are: the radio frequency power supply is 40-50W, the discharge gas is air, and the treatment time is 20-30 minutes.

[0028] In summary, this application includes at least one of the following beneficial technical effects:

[0029] 1. This application utilizes air plasma to treat the surface of nonwoven fabric, generating carboxyl groups on its surface, which effectively improves the hydrophilicity of the nonwoven fabric and can effectively improve its adhesion to the casting solution of the support, thereby improving the performance and durability of the reverse osmosis membrane.

[0030] 2. This application synthesizes sulfonated polyarylether ketone sulfone copolymer by polycondensation reaction of bisphenol A, 4,4'-difluorobenzophenone, 3,3'-disulfonated-4,4'-dichlorodiphenyl sulfone, and 4-carboxyphenylhydroquinone as raw materials under the catalysis of anhydrous potassium carbonate. The surface of the copolymer also contains carboxyl groups. The introduction of carboxyl and sulfonic acid groups not only effectively enhances the thermal stability and mechanical properties of the polymer material, but also effectively increases the hydrophilicity of the polymer material, thereby significantly enhancing the water flux of the reverse osmosis membrane.

[0031] 3. This application prepared fluorinated titanium dioxide using a simple precipitation method, and further synthesized a fluorinated titanium dioxide / metal-organic framework MIL-125(Ti) composite material using a hydrothermal reaction; then, through a simple water bath stirring method, the graphitic carbon nitride and the fluorinated titanium dioxide / metal-organic framework MIL-125(Ti) composite material achieved electrostatic self-assembly through π-π conjugation to obtain fluorinated titanium dioxide / metal-organic framework modified graphitic titanium nitride, which has excellent thermal stability and antifouling properties. When it is doped into the support casting solution and polyamide layer, it significantly enhances the high temperature resistance, chemical stability and hydrophilicity of the reverse osmosis membrane. The resulting reverse osmosis membrane also has excellent antifouling and antifouling properties, effectively improving the durability of the reverse osmosis membrane. Detailed Implementation

[0032] The present application will be further described in detail below with reference to the embodiments.

[0033] The chemical reagents used in the preparation examples, embodiments, and comparative examples provided in this invention are all commercially available products, and their brands and manufacturers are as follows:

[0034] 3-Amino-1,2-propanediol, Weifang Qianjin Fine Chemical Co., Ltd.;

[0035] Bisphenol A, Panhua Chemical (Shanghai) Co., Ltd.;

[0036] Graphite-phase carbon nitride, Henan Lavoisier Chemical Products Co., Ltd.;

[0037] Polyvinyl alcohol, Shanghai Aladdin Biochemical Technology Co., Ltd., P139549.

[0038] Preparation Example 1: Preparation of sulfonated polyarylether ketone sulfone copolymer

[0039] Preparation Example 1.1

[0040] 6.4 g of dried bisphenol A was mixed with 6 g of 4,4'-difluorobenzophenone, 6 g of 3,3'-disulfonated-4,4'-dichlorodiphenyl sulfone, 2.8 g of 4-carboxyphenylhydroquinone, and 16.6 g of anhydrous potassium carbonate and stirred until homogeneous. Then, 26 g of toluene and 54.6 g of sulfolane were added, and the mixture was heated to 40 °C and stirred until homogeneous. The temperature was then raised to 125 °C and refluxed for 4 h. Toluene was removed by distillation at 125 °C. The mixture was then heated to 185 °C and stirred for 24 h. After the reaction was completed, the material was discharged into deionized water, washed under boiling conditions until the water was clear, and then dried to obtain sulfonated polyarylether ketone sulfone copolymer.

[0041] Preparation Example 1.2

[0042] 8g of dried bisphenol A was mixed with 7.5g of 4,4'-difluorobenzophenone, 7.5g of 3,3'-disulfonated-4,4'-dichlorodiphenyl sulfone, 3.5g of 4-carboxyphenylhydroquinone, and 20.8g of anhydrous potassium carbonate and stirred until homogeneous. Then, 32.5g of toluene and 68g of sulfolane were added, and the mixture was heated to 45°C and stirred until homogeneous. The temperature was then raised to 135°C and refluxed for 5 hours. Toluene was removed by distillation at 135°C. The mixture was then heated to 190°C and stirred for 27 hours. After the reaction was completed, the material was discharged into deionized water, washed under boiling conditions until the water was clear, and then dried to obtain sulfonated polyarylether ketone sulfone copolymer.

[0043] Preparation Example 1.3

[0044] 9.6 g of dried bisphenol A was mixed with 9 g of 4,4'-difluorobenzophenone, 9 g of 3,3'-disulfonated-4,4'-dichlorodiphenyl sulfone, 4.2 g of 4-carboxyphenylhydroquinone, and 24.9 g of anhydrous potassium carbonate and stirred until homogeneous. Then, 39 g of toluene and 81.9 g of sulfolane were added, and the mixture was heated to 50 °C and stirred until homogeneous. The temperature was then raised to 145 °C and refluxed for 6 h. Toluene was removed by distillation at 145 °C. The mixture was then heated to 195 °C and stirred for 30 h. After the reaction was completed, the material was discharged into deionized water, washed under boiling conditions until the water was clear, and then dried to obtain sulfonated polyarylether ketone sulfone copolymer.

[0045] Preparation Example 2: Preparation of Fluorinated Titanium Dioxide / Metal-Organic Framework Modified Graphitic Carbon Nitride Preparation Example 2.1

[0046] S1. Add 40g of deionized water to 2.4g of titanium sulfate and stir until completely dissolved. Then, add 20.4g of hydrofluoric acid while stirring. After adding all the hydrofluoric acid, stir for 5 minutes. Then, adjust the pH of the system to 8 and continue stirring for 15 minutes. Then, let it stand for 20 minutes. Then, wash the sample by centrifugation with deionized water several times and dry it at 75°C. Grind the dried material into powder, put it into a crucible, and heat treat it in a muffle furnace at 520°C for 2 hours. After the heat treatment, let it cool naturally to the ambient temperature to obtain fluorinated titanium dioxide.

[0047] S2. Add 0.2g of fluorinated titanium dioxide prepared in S1 to 40g of deionized water, stir evenly, and then add 0.25g of tetrabutyl titanate; stir the mixture in an oil bath at 70℃ for 3h; separate the precipitate by centrifugation and wash with deionized water to remove contaminants, and obtain a clean precipitate. Mix 0.25g of trimesic acid with the clean precipitate, add 20g of deionized water, sonicate for 15min, and then transfer the mixture to a hydrothermal reactor and heat in an oven at 150℃ for 8h; after the reaction is completed, cool to room temperature, separate the precipitate by centrifugation, wash the precipitate, and then dry it at 80℃ to obtain the fluorinated titanium dioxide / metal-organic framework composite material.

[0048] S3. Add 0.03g of the fluorinated titanium dioxide / metal-organic framework composite material prepared in S2 to 8g of ethanol and ultrasonically disperse it evenly. Then add 0.5g of graphitic carbon nitride to 40g of ethanol and ultrasonically disperse it evenly. Subsequently, add the dispersion of the fluorinated titanium dioxide / metal-organic framework composite material dropwise to the dispersion of graphitic carbon nitride. After ultrasonic dispersion for 60min, stir at 60℃ for 5h, and then raise the temperature to 80℃ to evaporate the remaining ethanol to obtain fluorinated titanium dioxide / metal-organic framework modified graphitic carbon nitride.

[0049] Preparation Example 2.2

[0050] S1. Add 50g of deionized water to 3g of titanium sulfate and stir until completely dissolved. Then, add 25.7g of hydrofluoric acid while stirring. After all the hydrofluoric acid has been added, stir for 7.5 min. Then, adjust the pH of the system to 8.5 and continue stirring for 17.5 min. Then, let it stand for 22.5 min. Then, wash the sample by centrifugation with deionized water several times and dry it at 80℃. Grind the dried material into powder, put it into a crucible, and heat treat it in a muffle furnace at 550℃ for 3 h. After the heat treatment, let it cool naturally to the ambient temperature to obtain fluorinated titanium dioxide.

[0051] S2. Add 0.25g of fluorinated titanium dioxide prepared in S1 to 50g of deionized water, stir evenly, and then add 0.275g of tetrabutyl titanate; stir the mixture in an oil bath at 75℃ for 3.5h; separate the precipitate by centrifugation and wash with deionized water to remove contaminants, and obtain a clean precipitate. Mix 0.275g of trimesic acid with the clean precipitate, add 25g of deionized water, sonicate for 20min, and then transfer the mixture to a hydrothermal reactor and heat in an oven at 175℃ for 9h; after the reaction is completed, cool to room temperature, separate the precipitate by centrifugation, wash the precipitate, and then dry it at 85℃ to obtain the fluorinated titanium dioxide / metal-organic framework composite material;

[0052] S3. Add 0.045g of the fluorinated titanium dioxide / metal-organic framework composite material prepared in S2 to 12g of ethanol and ultrasonically disperse it evenly. Then add 0.75g of graphitic carbon nitride to 60g of ethanol and ultrasonically disperse it evenly. Subsequently, add the dispersion of the fluorinated titanium dioxide / metal-organic framework composite material dropwise to the dispersion of graphitic carbon nitride. After ultrasonic dispersion for 70min, stir at 62.5℃ for 6h, and then raise the temperature to 80℃ to evaporate the remaining ethanol to obtain fluorinated titanium dioxide / metal-organic framework modified graphitic carbon nitride.

[0053] Preparation Example 2.3

[0054] S1. Add 60g of deionized water to 3.6g of titanium sulfate and stir until completely dissolved. Then, add 30.7g of hydrofluoric acid while stirring. After adding all the hydrofluoric acid, stir for 10 minutes. Then, adjust the pH of the system to 9 and continue stirring for 20 minutes. Then, let it stand for 25 minutes. Then, wash the sample by centrifugation with deionized water several times and dry it at 85℃. Grind the dried material into powder, put it into a crucible, and heat treat it in a muffle furnace at 580℃ for 4 hours. After the heat treatment, let it cool naturally to the ambient temperature to obtain fluorinated titanium dioxide.

[0055] S2. Add 0.3g of fluorinated titanium dioxide prepared from S1 to 60g of deionized water, stir evenly, and then add 0.25g of tetrabutyl titanate; stir the mixture in an oil bath at 70℃ for 3h; separate the precipitate by centrifugation and wash with deionized water to remove contaminants, and obtain a clean precipitate. Mix 0.3g of trimesic acid with the clean precipitate, add 30g of deionized water, sonicate for 25min, and then transfer the mixture to a hydrothermal reactor and heat in an oven at 180℃ for 10h; after the reaction is completed, cool to room temperature, separate the precipitate by centrifugation, wash the precipitate, and then dry it at 90℃ to obtain the fluorinated titanium dioxide / metal-organic framework composite material;

[0056] S3. Add 0.06g of the fluorinated titanium dioxide / metal-organic framework composite material prepared in S2 to 16g of ethanol and ultrasonically disperse it evenly. Then add 1g of graphitic carbon nitride to 80g of ethanol and ultrasonically disperse it evenly. Subsequently, add the dispersion of the fluorinated titanium dioxide / metal-organic framework composite material dropwise to the dispersion of graphitic carbon nitride. After ultrasonic dispersion for 80min, stir at 65℃ for 7h. Then raise the temperature to 80℃ to evaporate the remaining ethanol to obtain fluorinated titanium dioxide / metal-organic framework modified graphitic carbon nitride.

[0057] Example 1

[0058] S1. Soak the polyester nonwoven fabric in a 25% isopropanol solution for 0.5 hours, rinse the isopropanol off the membrane surface with deionized water, and then dry it in an oven for later use. Place the dried nonwoven fabric flat on a workbench for plasma treatment. The plasma treatment conditions are: 40W power applied by the radio frequency power supply, air as the discharge gas, and 20 minutes for the treatment time. This yields the plasma-pretreated nonwoven fabric.

[0059] S2. Mix 12% of the sulfonated polyarylether ketone sulfone copolymer prepared in Preparation Example 1.1, 3% of the fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride prepared in Preparation Example 2.1, 84% of N,N-dimethylformamide, and 1% of the pore-forming agent polyvinyl alcohol by mass percentage, stir evenly, let stand for 1 hour, and then degas by ultrasonication for 10 minutes to obtain the support casting solution.

[0060] S3. The support casting solution obtained in S2 is applied to the plasma pretreated nonwoven fabric obtained in S1 with a thickness of 50 μm; then it is evaporated at room temperature for 10 s and then immersed in 15℃ deionized water to gel and solidify into a film; then it is dried in an oven at 50℃ for 5 hours to obtain the support layer.

[0061] S4. 5% butanediamine, 0.01% fluorinated titanium dioxide / metal-organic framework modified graphite carbon nitride prepared in Preparation Example 2.1, 0.04% 3-amino-1,2-propanediol, and 94.95% deionized water were mixed thoroughly by mass percentage to obtain component A; 5% succinyl chloride and 95% N,N-dimethylformamide were mixed thoroughly by mass percentage to obtain component B.

[0062] S5. The surface of the support layer obtained in S3 is first immersed in component A for 30s, and then left to stand at room temperature for 5s; then immersed in component B for 10s, and then left to stand at room temperature for 8min. After that, it is placed in a drying oven and dried at 40℃ for 6h to obtain the functional membrane layer, thus obtaining the high temperature resistant reverse osmosis membrane.

[0063] Example 2

[0064] S1. Soak the polyester nonwoven fabric in a 25% isopropanol solution for 0.75 hours, rinse the isopropanol off the membrane surface with deionized water, and then dry it in an oven for later use. Place the dried nonwoven fabric flat on a workbench for plasma treatment. The plasma treatment conditions are: 45W applied power from the radio frequency power supply, air as the discharge gas, and 25 minutes for the treatment time. This yields the plasma-pretreated nonwoven fabric.

[0065] S2. Mix 16% of the sulfonated polyarylether ketone sulfone copolymer prepared in Preparation Example 1.2, 5% of the fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride prepared in Preparation Example 2.2, 77.5% N,N-dimethylformamide, and 1.5% of the pore-forming agent polyvinyl alcohol by mass percentage, stir evenly, let stand for 2 hours, and then degas by ultrasonication for 20 minutes to obtain the support casting solution.

[0066] S3. The support casting solution obtained in S2 is applied to the plasma pretreated nonwoven fabric obtained in S1 with a thickness of 100 μm; then it is evaporated at room temperature for 20 s and then immersed in deionized water at 20 °C to gel and solidify into a film; then it is dried in an oven at 60 °C for 6.5 hours to obtain the support layer.

[0067] S4. 7.5% butanediamine, 0.02% fluorinated titanium dioxide / metal-organic framework modified graphite carbon nitride prepared in Preparation Example 2.2, 0.05% 3-amino-1,2-propanediol, and 91.8% deionized water were mixed evenly according to mass percentage to obtain component A; 7.5% succinyl chloride and 92.5% N,N-dimethylformamide were mixed evenly according to mass percentage to obtain component B.

[0068] S5. The surface of the support layer obtained in S3 is first immersed in component A for 45s, and then left to stand at room temperature for 20s; then immersed in component B for 20s, and then left to stand at room temperature for 10min. After that, it is placed in a drying oven and dried at 50℃ for 4h to obtain the functional membrane layer, thus obtaining the high temperature resistant reverse osmosis membrane.

[0069] Example 3

[0070] S1. Soak the polyester nonwoven fabric in a 25% isopropanol solution for 1 hour, rinse the isopropanol off the membrane surface with deionized water, and then dry it in an oven for later use. Place the dried nonwoven fabric flat on a workbench for plasma treatment. The plasma treatment conditions are: 50W applied power from the radio frequency power supply, air as the discharge gas, and 30 minutes for the treatment time. This will give you the plasma-pretreated nonwoven fabric.

[0071] S2. 21% of the sulfonated polyarylether ketone sulfone copolymer prepared in Preparation Example 1.3, 7% of the fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride prepared in Preparation Example 2.3, 70% of N,N-dimethylformamide, and 2% of the pore-forming agent polyvinyl alcohol were mixed by mass percentage, stirred evenly, allowed to stand for 3 hours, and then ultrasonically degassed for 30 minutes to obtain the support casting solution.

[0072] S3. The support casting solution obtained in S2 is applied to the plasma pretreated nonwoven fabric obtained in S1 with a thickness of 150 μm; then it is evaporated at room temperature for 30 s and then immersed in deionized water at 25 °C to gel and solidify into a film; then it is dried in an oven at 70 °C for 8 hours to obtain the support layer.

[0073] S4. 10% butanediamine, 0.03% fluorinated titanium dioxide / metal-organic framework modified graphite carbon nitride prepared in Preparation Example 2.3, 0.06% 3-amino-1,2-propanediol, and 89.91% deionized water were mixed evenly according to mass percentage to obtain component A; 10% succinyl chloride and 90% N,N-dimethylformamide were mixed evenly according to mass percentage to obtain component B.

[0074] S5. The surface of the support layer obtained in S3 is first immersed in component A for 60s, and then left to stand at room temperature for 30s; then immersed in component B for 30s, and then left to stand at room temperature for 12min. After that, it is placed in a drying oven and dried at 60℃ for 2h to obtain the functional membrane layer, thus obtaining the high temperature resistant reverse osmosis membrane.

[0075] Comparative Example 1

[0076] The difference between Comparative Example 1 and Example 1 is that the polyester nonwoven fabric was not subjected to plasma treatment in Comparative Example 1.

[0077] Comparative Example 2

[0078] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, an equal amount of trifluoromethane polyarylene ether is used instead of the sulfonated polyarylene ether ketone sulfone copolymer prepared in Preparation Example 1.1.

[0079] Comparative Example 3

[0080] The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 does not add fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride in S2.

[0081] Comparative Example 4

[0082] The difference between Comparative Example 4 and Example 1 is that Comparative Example 4 does not add fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride in S2.

[0083] Performance testing

[0084] I. The high-temperature resistant reverse osmosis membranes obtained in Examples 1-3 and Comparative Examples 1-4 were continuously operated for 72 hours in a 2000 ppm sodium chloride solution at operating temperatures of 25, 50, and 85°C and an operating pressure of 1.55 MPa. The desalination and water permeation performance were tested, and the results are shown in Table 1.

[0085] The specific test results are as follows:

[0086] Table 1 Performance Test Results

[0087]

[0088] As can be seen from the test methods in Table 1, after the high-temperature resistant reverse osmosis membrane provided in this application was continuously operated at 25, 50, and 85°C for 72 hours, the water flux of the reverse osmosis composite membrane in the examples increased with the increase of the test temperature, while the desalination rate changed little and maintained a very high desalination rate. In contrast, the desalination rate of the reverse osmosis composite membrane in the comparative example decreased significantly with the increase of the treatment temperature. Therefore, the high-temperature resistant reverse osmosis composite membrane provided in this application always maintains a relatively high desalination rate and water flux. The reverse osmosis composite membrane did not deform, break, or peel off during high-temperature operation, which can effectively improve its excellent heat resistance and mechanical properties.

[0089] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high-temperature resistant reverse osmosis membrane, characterized in that: It includes a nonwoven fabric layer, a support layer, and a functional membrane layer; the nonwoven fabric layer is a plasma-pretreated nonwoven fabric. The support layer is obtained by curing the support casting solution on a nonwoven fabric after plasma pretreatment; the functional film layer is a polyamide layer doped with functional fillers. The raw materials of the support casting solution include, by mass percentage, 12-21% sulfonated polyaryletherketone sulfone copolymer, 3-7% fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride, 70-84% N,N-dimethylformamide, and 1-2% pore-forming agent. The polyamide layer raw material doped with functional fillers includes component A and component B; component A includes, by mass percentage, 5-10% fatty amine, 0.01-0.03% fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride, 0.04-0.06% 3-amino-1,2-propanediol, and the balance being water; component B includes, by mass percentage, 5-10% fatty acyl chloride, and the balance being organic solvent.

2. The high-temperature resistant reverse osmosis membrane according to claim 1, characterized in that: The sulfonated polyarylether ketone sulfone copolymer is prepared from the following raw materials in parts by weight: 6.4-9.6 parts bisphenol A, 6-9 parts 4,4'-difluorobenzophenone, 6-9 parts 3,3'-disulfonated-4,4'-dichlorodiphenyl sulfone, 2.8-4.2 parts 4-carboxyphenylhydroquinone, 16.6-24.9 parts anhydrous potassium carbonate, 26-39 parts toluene, and 54.6-81.9 parts sulfolane.

3. The high-temperature resistant reverse osmosis membrane according to claim 2, characterized in that: The preparation method of the sulfonated polyarylether ketone sulfone copolymer includes the following steps: 6.4-9.6 parts of dried bisphenol A were mixed with 6-9 parts of 4,4'-difluorobenzophenone, 6-9 parts of 3,3'-disulfonated-4,4'-dichlorodiphenyl sulfone, 2.8-4.2 parts of 4-carboxyphenylhydroquinone, and 16.6-24.9 parts of anhydrous potassium carbonate and stirred until homogeneous. Then, 26-39 parts of toluene and 54.6-81.9 parts of sulfolane were added, and the mixture was heated to 40-50°C and stirred until homogeneous. The temperature was then raised to 125-145°C and refluxed for 4-6 hours. Toluene was removed by distillation at 125-145°C. The mixture was then heated to 185-195°C and stirred for 24-30 hours. After the reaction was completed, the mixture was removed from the water, washed under boiling conditions until the water was clear, and then dried to obtain the sulfonated polyarylether ketone sulfone copolymer.

4. The high-temperature resistant reverse osmosis membrane according to claim 1, characterized in that: The fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride is prepared from the following raw materials in parts by weight: 0.03-0.06 parts fluorinated titanium dioxide / metal-organic framework composite material, 48-96 parts ethanol, and 0.5-1 parts graphite phase carbon nitride.

5. The high-temperature resistant reverse osmosis membrane according to claim 4, characterized in that: The fluorinated titanium dioxide / metal-organic framework composite material is prepared from the following raw materials in parts by weight: 0.2-0.3 parts fluorinated titanium dioxide, 60-90 parts water, 0.25-0.3 parts trimesic acid, and 0.25-0.3 parts tetrabutyl titanate; The preparation method of the fluorinated titanium dioxide / metal-organic framework composite material includes the following steps: Add 0.2-0.3 parts of fluorinated titanium dioxide to 40-60 parts of water, stir evenly, and then add 0.25-0.3 parts of tetrabutyl titanate. Stir the mixture in an oil bath at 70-80℃ for 3-4 hours. Separate the precipitate by centrifugation and wash to remove contaminants, obtaining a clean precipitate. Mix 0.25-0.3 parts of trimesic acid with the clean precipitate, add 20-30 parts of water, and sonicate for 15-25 minutes. Transfer the mixture to a hydrothermal reactor and heat in an oven at 150-180℃ for 8-10 hours. After the reaction is complete, cool to room temperature, separate the precipitate by centrifugation, wash the precipitate, and then dry it at 80-90℃ to obtain the fluorinated titanium dioxide / metal-organic framework composite material.

6. The high-temperature resistant reverse osmosis membrane according to claim 5, characterized in that: The method for preparing the fluorinated titanium dioxide includes the following steps: By weight, add 40-60 parts of water to 2.4-3.6 parts of titanium sulfate and stir until completely dissolved. Then, add 20.4-30.7 parts of hydrofluoric acid while stirring, and stir for 5-10 minutes after all the hydrofluoric acid has been added. Then, adjust the pH of the system to 8-9 and continue stirring for 15-20 minutes, and then let it stand for 20-25 minutes. Then, wash the sample by multiple water centrifugations and dry it at 75-85℃. Grind the dried material into powder, put it into a crucible, and heat treat it in a muffle furnace at 520-580℃ for 2-4 hours. After the heat treatment, let it cool naturally to the ambient temperature to obtain fluorinated titanium dioxide.

7. The high-temperature resistant reverse osmosis membrane according to claim 4, characterized in that: The method for preparing fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride includes the following steps: 0.03-0.06 parts of fluorinated titanium dioxide / metal-organic framework composite material were added to 8-16 parts of ethanol and ultrasonically dispersed evenly. Then, 0.5-1 parts of graphitic carbon nitride were added to 40-80 parts of ethanol and ultrasonically dispersed evenly. Subsequently, the dispersion of fluorinated titanium dioxide / metal-organic framework composite material was added dropwise to the dispersion of graphitic carbon nitride. After ultrasonic dispersion for 60-80 min, the mixture was stirred at 60-65℃ for 5-7 h. The remaining ethanol was then evaporated by raising the temperature to obtain fluorinated titanium dioxide / metal-organic framework modified graphitic carbon nitride.

8. A process for preparing a high-temperature resistant reverse osmosis membrane according to any one of claims 1-7, comprising the following steps: S1. Soak the nonwoven fabric in isopropanol solution for 0.5-1h, rinse the isopropanol off the membrane surface with water, and dry it in an oven for later use; place the dried nonwoven fabric flat on the workbench for plasma treatment to obtain plasma pretreated nonwoven fabric. S2. Mix 12-21% sulfonated polyarylether ketone sulfone copolymer, 3-7% fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride, 70-84% N,N-dimethylformamide, and 1-2% pore-forming agent by mass percentage, stir evenly, let stand for 1-3 hours, and then degas by ultrasonication for 10-30 minutes to obtain the support casting solution. S3. The support casting solution obtained in S2 is applied to the plasma pretreated nonwoven fabric obtained in S1 with a thickness of 50-150μm; then evaporated at room temperature for 10-30s and then immersed in water at 15-25℃ to gel and solidify into a film; then dried in an oven at 50-70℃ for 5-8 hours to obtain the support layer. S4. Mix 5-10% fatty amine, 0.01-0.03% fluorinated titanium dioxide / metal-organic framework modified graphite phase carbon nitride, 0.04-0.06% 3-amino-1,2-propanediol, and the balance being water by mass percentage to obtain component A; mix 5-10% fatty acyl chloride and the balance being organic solvent by mass percentage to obtain component B. S5. The surface of the support layer obtained in S3 is first immersed in component A for 30-60s, and then left to stand at room temperature for 5-30s; then immersed in component B for 10-30s, and then left to react at room temperature for 8-12min. After that, it is placed in a drying oven and dried at 40-60℃ for 2-6h to obtain the functional membrane layer, thus obtaining the high-temperature resistant reverse osmosis membrane.

9. The preparation process of a high-temperature resistant reverse osmosis membrane according to claim 8, characterized in that: The plasma treatment conditions are as follows: the power applied by the radio frequency power supply is 40-50W, the discharge gas is air, and the treatment time is 20-30 minutes.

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