Separation membrane and preparation method thereof

Abstract

The invention discloses a separation membrane and a preparation method thereof, relates to the technical field of separation membranes, and aims to solve the problem of how to improve the selective separation efficiency of the separation membrane. The separation membrane comprises a main body layer with a microcosmic lamellar structure and an organic material distributed among lamellar layers of the main body layer. The main body layer and the organic material are connected through covalent bonds.

Description

Technical Field

[0001] The present application relates to the technical field of separation membranes, and in particular to a separation membrane and a preparation method thereof. Background Art

[0002] Membrane separation technology has seen unprecedented development due to its advantages, such as low energy consumption and simple operation. However, the trade-off between membrane permeability and selectivity remains a critical weakness. Smaller membrane pore sizes increase resistance to fluid flow, reducing the amount of permeate per unit time and lowering membrane permeability. Larger membrane pore sizes, however, increase permeate per unit time. While the membrane's permeability improves, its selectivity struggles to maintain. Both of these factors impact the membrane's selective separation efficiency, thereby reducing its overall efficiency and practicality. Summary of the Invention

[0003] The purpose of this application is to provide a separation membrane and a preparation method thereof, aiming to improve the efficiency of selective separation of the separation membrane.

[0004] To achieve the above objectives, this application adopts the following technical solutions:

[0005] In a first aspect, the present application provides a separation membrane. The separation membrane comprises: a main layer having a lamellar structure and an organic material distributed between the lamellar layers of the main layer.

[0006] The host layer and the organic material are connected via covalent bonds.

[0007] In the separation membrane provided in the embodiment of the present application, the main layer has a lamellar structure and is the skeleton support layer of the separation membrane. Moreover, the main layer exists in a lamellar structure, which provides space for the insertion of organic materials. The organic materials are distributed between the lamellar layers of the main layer, which can change the structural layout between the layers and adjust the distance between the layers of the main layer, that is, the interlayer spacing. The interlayer spacing is the pore size of the two-dimensional nanochannel and can be used to determine the size of the particles that the separation membrane can permeate.

[0008] At the same time, the main layer and the organic material are connected by covalent bonds, ensuring a close bond between the main layer and the organic material. This also prevents the organic material from falling off or migrating during use, improving the stability of the separation membrane's selective separation and further enhancing its selective separation efficiency. This achieves precise selectivity for small molecules or ions. By intercalating organic materials into the main layer, its pore size can be effectively controlled, thereby improving its separation performance. Intercalation of organic materials not only changes the interlayer distance of the main layer but also modulates its surface chemical properties, enabling the separation membrane to exhibit different separation characteristics under different conditions.

[0009] In some embodiments, the spacing between the sheets of the bulk layer ranges from 0.8 nm to 2.8 nm.

[0010] In some embodiments, the host layer includes at least one of graphene oxide, boron nitride, a two-dimensional transition metal carbon / nitrogen compound, and a clay mineral.

[0011] In some embodiments, the organic material includes an organic amine compound.

[0012] In a second aspect, the present application provides a method for preparing a separation membrane. The method for preparing the separation membrane comprises:

[0013] The main material source, the organic material source and the condensing agent are mixed and reacted. And,

[0014] The reaction product is filtered and dried in sequence to obtain a separation membrane; the separation membrane comprises: a main layer with a lamellar structure and an organic material distributed between the lamellar layers of the main layer; wherein the material of the main layer and the organic material are connected by covalent bonds.

[0015] In some embodiments, the host material source includes at least one of graphene oxide, carboxylated boron nitride, carboxylated two-dimensional transition metal carbon / nitrogen compounds, and carboxylated clay minerals.

[0016] In some embodiments, the organic material source includes at least one of 2,4-diamino-6-dodecylamine-1,3,5-triazine, an octadecylamine derivative, and a hexylamine derivative.

[0017] In some embodiments, the reaction temperature ranges from 85°C to 90°C.

[0018] In some embodiments, the reaction time ranges from 0.8 hours to 1.5 hours.

[0019] In some embodiments, the method for preparing a separation membrane further comprises, before mixing and reacting the host material source, the organic material source, and the condensing agent, preparing an organic material source, comprising:

[0020] Ammonia water is added to the solution of a chlorine- or thiocyanate-containing compound to carry out the reaction.

[0021] The product after the reaction is filtered to obtain a solid product.

[0022] The solid product, the aliphatic amine compound and the acid scavenger are mixed and reacted.

[0023] The product after the reaction is filtered to obtain an organic material source.

[0024] In some embodiments, the chlorine- or thiocyanate-containing compound includes at least one of cyanuric chloride, melamine, and thiocyanic acid.

[0025] In some embodiments, the aliphatic amine compound includes at least one of hexylamine, dodecylamine, octadecylamine, heptylamine, and nonylamine. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 A flow chart of a method for preparing a separation membrane provided in an embodiment of the present application;

[0028] Figure 2 This is the element distribution diagram of the separation membrane of Example 1 of the present application;

[0029] Figure 3 The attenuated total reflection Fourier transform infrared spectra of 2,4-diamino-6-dodecylamine-1,3,5-triazine, graphene oxide and the separation membrane of Example 1 of the present application are shown;

[0030] Figure 4 X-ray diffraction patterns of graphene oxide and the separation membrane of Example 1 of the present application;

[0031] Figure 5 Graphene oxide and the separation membrane of Example 1 of the present application are Raman spectra;

[0032] Figure 6 The thermogravimetric analysis curves of graphene oxide, 2,4-diamino-6-dodecylamine-1,3,5-triazine and the separation membrane of Example 1 of the present application;

[0033] Figure 7 is the X-ray photoelectron spectrum of graphene oxide;

[0034] Figure 8 This is an X-ray photoelectron spectrum of the separation membrane of Example 1 of the present application. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0037] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0038] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0039] An embodiment of the present application provides a separation membrane. The separation membrane includes: a material of the separation membrane includes: a main layer having a sheet structure and an organic material distributed between the sheets of the main layer.

[0040] The host layer and the organic material are connected via covalent bonds.

[0041] It can be understood that the lamellar structure of the main layer is the skeleton support layer of the separation membrane, and the main layer exists in a lamellar structure, which provides space for the insertion of organic materials. The organic materials are distributed between the lamellar layers of the main layer, which can change the structural layout between the layers and adjust the distance between the layers of the main layer, that is, the interlayer spacing. The interlayer spacing is the pore size of the two-dimensional nanochannel and can be used to determine the size of the particles that the separation membrane can penetrate.

[0042] At the same time, the main layer and the organic material are connected by covalent bonds, ensuring a close bond between the main layer and the organic material. This also prevents the organic material from falling off or migrating during use, improving the stability of the separation membrane's selective separation and further enhancing its selective separation efficiency. This achieves precise selectivity for small molecules or ions. By intercalating organic materials into the main layer, its pore size can be effectively controlled, thereby improving its separation performance. Intercalation of organic materials not only changes the interlayer distance of the main layer but also modulates its surface chemical properties, enabling the separation membrane to exhibit different separation characteristics under different conditions.

[0043] In some embodiments, the spacing between the sheets of the bulk layer ranges from 0.8 nm to 2.8 nm.

[0044] For example, the spacing between the sheets of the main layer may be 0.8 nm, 1.3 nm, 1.8 nm, 2.3 nm, or 2.8 nm, etc., which is not limited here.

[0045] Here, the distance between the sheets of the main layer can be approximately regarded as the pore size of the separation membrane.

[0046] It can be understood that setting the spacing between the main layer layers in the range of 0.8nm to 2.8nm can be used for separation of different systems. For example, when the interlayer spacing of the separation membrane is 0.88nm, the separation membrane can be applied to the separation of small molecule gases (such as CO2 and N2 separation), separation of monosaccharides and disaccharides, and separation of monovalent ions (such as Na + , K + ) and multivalent ions (such as Ca2 + , SO42-). Among them, the separation factor of CO2 and N2 separation (indicating the ratio of the purity or concentration of the two gases after separation to the original mixed gas) is about 150, the retention rate of monovalent ions is greater than 95%, the retention rate of multivalent ions is greater than 99%, and the water flux is 25L / (m 2 ·h·bar). When the interlayer spacing of the separation membrane is 1.62nm, the separation membrane can be used for water treatment (such as heavy metal ion and organic matter retention) and biomolecule separation (such as antibiotic and protein separation). 2 + and Cd 2 +) retention rate is greater than 94.5%, and antibiotic flux is greater than or equal to 30L / (m 2 ·h·bar), the final water purity is greater than 98%.

[0047] In some embodiments, the host layer includes at least one of graphene oxide, boron nitride, a two-dimensional transition metal carbon / nitrogen compound, and a clay mineral.

[0048] Here, the graphene oxide is graphene oxide obtained by reacting carboxyl groups on the graphene oxide with organic materials to form co-bonds.

[0049] Graphene oxide (GO), produced by oxidizing graphite, has a sheet-like structure ranging from one to several atomic layers thick. Van der Waals forces hold the layers together, forming large sheets. Boron nitride (BN) derivatives have a layered structure similar to graphite, with layers bonded by van der Waals forces, making them typical two-dimensional materials. Two-dimensional transition metal carbon / nitrogen compounds, similar to GO, have a distinct layered structure. Clay minerals have a lamellar crystal structure.

[0050] The graphene oxide derivatives, boron nitride, two-dimensional transition metal carbon / nitrogen compounds or clay minerals included in the above-mentioned main layer are all layered structures, which can make the organic materials distributed between the layers and connected by covalent bonds, change the tension or structural layout between the layers, adjust and increase the distance between the layers, so that the pore size of the separation membrane becomes larger, so that the separation membrane can improve the permeability of the separation membrane while ensuring high selectivity, thereby achieving efficient selective separation.

[0051] Furthermore, when the main layer of the separation membrane is a graphene oxide derivative, it can be applied to water treatment. Because graphene oxide derivatives are carbon materials, they have excellent anti-fouling properties, with flux decay of less than 5% after 100 hours of continuous operation, enabling sustained, efficient, selective separation and filtration with excellent stability.

[0052] In some embodiments, the organic material includes an organic amine compound.

[0053] Understandably, organic amine compounds have abundant amino (–NH2) functional groups, which have good chemical reactivity and hydrophilicity, and can regulate the surface chemical properties of the separation membrane, thereby improving the hydrophilicity and permeability of the separation membrane; achieving efficient selective separation, and the amino functional groups can combine with the main layer, such as combining with the carboxyl groups in graphene oxide, so that the stability of the separation membrane is improved, and efficient selective separation is continuously performed.

[0054] In a second aspect, the embodiments of the present application provide a method for preparing a separation membrane. Figure 1 As shown, the preparation method of the separation membrane includes: S1 to S2.

[0055] S1: mixing a main material source, an organic material source and a condensing agent and reacting them.

[0056] S2: The reaction product is filtered and dried in sequence to obtain a separation membrane. The separation membrane comprises: a main layer having a lamellar structure and an organic material distributed between the lamellar layers of the main layer; wherein the material of the main layer and the organic material are connected by covalent bonds.

[0057] Exemplary, condensing agent is a chemical substance used to promote condensation reaction between organic molecules or functional groups during material synthesis. It usually plays a connecting or bridging role, so that monomers or precursor molecules form polymers or hybrid materials through condensation reaction. The condensing agent can be 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU reagent), 6-chlorobenzotriazole-1,1,3,3-tetramethyluronium hexafluorophosphate (HCTU reagent), O-((ethoxycarbonyl) cyanomethyleneamino)-N,N,N',N'-tetramethyluronium tetrafluoroborate (TOTU reagent), at least one of benzotriazole tetramethyl tetrafluoroboric acid (TBTU reagent).

[0058] It can be understood that S1 introduces a main layer source with a lamellar structure as a skeleton support layer of the separation membrane. S2 introduces an organic material source. S3 mixes the organic material and the main layer and uses a condensing agent to activate the groups on the surface of the main layer source (such as carboxyl groups) so that they undergo a condensation reaction with the groups of the organic material source (such as amino groups in organic amines) to form covalent bonds (such as amide bonds -CONH-), so that the organic material is stably distributed between the lamellar layers of the main layer, and finally filtered and dried to form a separation membrane. The above preparation method is simple and effective, the interlayer spacing is adjustable, and different interlayer spacings can be designed for different usage scenarios.

[0059] In some embodiments, the host material source includes at least one of graphene oxide, carboxylated boron nitride, carboxylated two-dimensional transition metal carbon / nitrogen compounds (Mxene), and carboxylated clay minerals.

[0060] It can be understood that graphene oxide, carboxylated boron nitride, carboxylated two-dimensional transition metal carbon / nitrogen compounds and carboxylated clay minerals all contain rich carboxyl groups, which can react with organic material sources (such as amino groups on organic materials) to form covalent bonds, such as amide bonds, so that the organic material is inserted into the middle of the layer of organic material, that is, the intercalation treatment obtains a separation membrane with adjustable pores.

[0061] In some embodiments, the organic material source includes at least one of 2,4-diamino-6-dodecylamine-1,3,5-triazine (DADT), an octadecylamine derivative (DAOT), and a hexylamine derivative (DAHT).

[0062] It can be understood that 2,4-diamino-6-dodecylamine-1,3,5-triazine, octadecylamine derivatives and hexylamine derivatives all contain multiple amino functional groups, have good reactivity, and react with functional groups in the main layer (such as the above-mentioned graphene oxide, carboxylated boron nitride, carboxylated two-dimensional transition metal carbon / nitrogen compounds and carboxylated clay minerals) to form covalent bonds, such as amide bonds.

[0063] For example, graphene oxide, carboxylated boron nitride, carboxylated two-dimensional transition metal carbon / nitrogen compounds and carboxylated clay minerals all contain rich carboxyl groups, and 2,4-diamino-6-dodecylamine-1,3,5-triazine, octadecylamine derivatives and hexylamine derivatives all contain multiple amino functional groups. Carboxylic acid is activated in the presence of HATU reagent to promote the reaction between carboxylic acid and amino group to form an amide bond. That is to say, the main layer source is converted into the main layer of the separation membrane, for example, graphene oxide, carboxylated boron nitride, carboxylated two-dimensional transition metal carbon / nitrogen compounds and carboxylated clay minerals are converted into graphene oxide derivatives, boron nitride, two-dimensional transition metal carbon / nitrogen compounds and clay minerals respectively; the organic material source is converted into the organic material of the separation membrane, for example, DADT, DAOT and DAHT are converted into organic amine compounds, so that the organic material is inserted into the middle layer of the main layer to obtain a separation membrane with adjustable pores.

[0064] In some embodiments, the reaction temperature ranges from 85°C to 90°C.

[0065] For example, the reaction temperature can be 85° C., 86° C., 87° C., 88° C., 89° C., or 90° C., etc., which is not limited here.

[0066] It can be understood that the reaction temperature is within the range of 85° C. to 90° C., which can effectively promote the condensation reaction of the main layer and the organic material, help improve the reaction efficiency, and avoid unevenness or side reactions caused by too fast a reaction.

[0067] In some embodiments, the reaction time ranges from 0.8 hours to 1.5 hours.

[0068] For example, the reaction temperature can be 0.8 hours, 0.9 hours, 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours or 1.5 hours, etc., which is not limited here.

[0069] It can be understood that the reaction time is within the range of 0.8 hours to 1.5 hours, which can provide sufficient time for the condensation reaction of the main layer and the organic material to complete, and can avoid the situation where a longer reaction time (for example, greater than 1.5 hours) may cause the membrane structure to deteriorate or a side reaction occurs, or a shorter time (for example, less than 1.5 hours) causes insufficient reaction and leads to an incomplete membrane; ensuring that the organic material source, the condensation agent and the main layer source react fully to form a uniform and complete membrane structure, which helps to form a dense, uniform and good performance separation membrane and reduce unreacted raw materials or by-products.

[0070] In some embodiments, the method for preparing the separation membrane further includes, S1, preparing the organic material source before mixing the main material source, the organic material source and the condensing agent for reaction, comprising: steps (1) to (4).

[0071] Step (1): adding ammonia water to a solution of a chlorine-containing or thiocyanate-containing compound to carry out a reaction.

[0072] Illustratively, the chlorine- or thiocyanate-containing compound includes at least one of cyanuric chloride, melamine, and thiocyanic acid.

[0073] Step (2): Filter the product after the reaction to obtain a solid product.

[0074] Step (3): mixing the solid product, the aliphatic amine compound and the acid scavenger and reacting them.

[0075] Exemplarily, the aliphatic amine compound includes at least one of hexylamine, dodecylamine, octadecylamine, heptylamine and nonylamine.

[0076] Step (4): Filter the reaction product to obtain an organic material source.

[0077] It can be understood that ammonia water is added dropwise to a solution of a compound containing chlorine or thiocyanate, and the chlorine or thiocyanate reacts with the ammonia water to undergo a substitution reaction, and a solid product with an active group (-NH2 / -OH) is obtained after filtration; then, in the presence of an acid scavenger, aliphatic amine compounds of different chain lengths are introduced into the solid product to form organic material sources with different chain lengths. The acid scavenger can neutralize the reaction and promote the reaction. Finally, after filtration, a more stable organic material source with amino functional groups is obtained for the subsequent preparation of separation membranes.

[0078] Exemplarily, when the chlorine- or thiocyanate-containing compound is cyanuric chloride, S2 provides an organic material source, including: first dispersing cyanuric chloride powder in a solvent at 0°C to 45°C, then adding ammonia water and maintaining the temperature at 0°C to 45°C for reaction for 30min to 35min, then quickly raising the temperature to 53°C to 75°C, and then reacting for 30min to 35min to complete the reaction of cyanuric chloride. This is because the three chlorine atoms in the cyanuric chloride molecule have different reactivity at different temperatures. By setting the reaction in different temperature sections, the chlorine atoms at different positions can be activated, so that the cyanuric chloride reacts completely.

[0079] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, were purchased from conventional biochemical reagent stores.

[0080] Example 1

[0081] Example 1 provides a separation membrane. The preparation method of the separation membrane includes: steps (1A) to (3A).

[0082] Step (1A): At 45°C, 9.24 g of cyanuric chloride powder was added to a three-necked flask, followed by the slow addition of 76 mL of refrigerated acetone and 80 mL of refrigerated deionized water. After magnetic stirring, a uniform suspension was formed. During this process, the temperature was maintained at 45°C. 1 mol·L -1 , 108 mL of ammonia water was slowly added dropwise to the above suspension, and then the temperature was maintained at 45 ° C for 30 minutes, and then the temperature was quickly raised to 65 ° C for another 30 minutes. After the reaction, the solid at the bottom of the three-necked flask was taken out and filtered. The filter cake was repeatedly rinsed with deionized water and then dried in a blast oven at 45 ° C to obtain 4.2 g of 2,4-diamino-6-chloro-1,3,5-triazine (DACT).

[0083] Step (2A): 4.2 g of DACT was dissolved in 200 mL of 1,4-dioxane, 11.1 g of dodecylamine was added, and 2 g of sodium carbonate was added as an acid scavenger. The mixture was then refluxed at 90° C. for 6 h. After the reaction, the solid product was filtered, the filter cake was rinsed with a large amount of deionized water, and the filter cake was recrystallized from ethanol to obtain 9.3 g of 2,4-diamino-6-dodecylamine-1,3,5-triazine (DADT).

[0084] Step (3A): 80 mg of GO was dispersed in 80 mL of dry N,N-dimethylformamide and sonicated for 15 min to obtain a stable suspension. 800 mg of DADT and 2 mg of HATU were then added, and the mixture was heated to 90°C for 1 h. The mixture was filtered through a polyvinylidene fluoride membrane (pore size = 0.45 μm) to obtain a GO-DADT solid. The solid was repeatedly washed with deionized water and finally freeze-dried to obtain a separation membrane with a pore size of 1.2 nm to 1.9 nm.

[0085] like Figure 2 As shown, Figure 2 2 is an element distribution diagram of the separation membrane of Example 1. It can be seen that the C, N, and O elements are evenly distributed in the diagram, among which the N element can only come from DADT, indicating that DADT is relatively evenly distributed in the separation membrane of Example 1.

[0086] like Figure 3 As shown, Figure 3 The attenuated total reflection Fourier transform infrared spectra of 2,4-diamino-6-dodecylamine-1,3,5-triazine, graphene oxide and the separation membrane of Example 1 show that DADT is covalently grafted onto the GO nanosheets. For GO, the attenuated total reflection Fourier transform infrared spectra of 2,4-diamino-6-dodecylamine-1,3,5-triazine, graphene oxide and the separation membrane of Example 1 can be seen at 1726 cm -1 、1216cm -1 and 1038cm -1 Typical peaks corresponding to carbonyl (from -COOH), hydroxyl and epoxy groups were observed at 813 cm-1 The absorption peak at 1716 cm is attributed to 1,3,5s-triazine. Out-of-plane vibration can be found in the spectrum of the separation membrane of Example 1, which indicates that DADT is inserted into the GO nanosheets. -1 The peak at 1654 cm-1 is attributed to -C=O from the carboxyl group, but it becomes very weak. -1 、1553cm -1 and 1163cm -1 The three typical peaks at correspond to -C=O (amide I band), -NH (amide II band) and CN, respectively, indicating that amide groups are formed on the separation membrane of Example 1.

[0087] like Figure 4 As shown, Figure 4 The following are X-ray diffraction patterns of graphene oxide and the separation membrane from Example 1. The diffraction peak at 2θ = 11.7°, attributed to the (001) diffraction plane of GO, shifts to 7.2° after modification, confirming the insertion of DADT molecules into GO. The spacing of the separation membrane from Example 1 increases by 0.471 nm. Since carboxyl groups are primarily distributed at the edges of GO nanosheets, the covalent bond between GO and DADT consists of an amide bond.

[0088] like Figure 5 As shown, Figure 5 3 is a Raman spectrum of graphene oxide and the separation membrane of Example 1. It can be seen that the G peak of the separation membrane of Example 1 is significantly reduced, indicating that the insertion of organic materials has led to a decrease in the orderliness of GO.

[0089] like Figure 6 As shown, Figure 6 The thermogravimetric analysis curves of graphene oxide, 2,4-diamino-6-dodecylamine-1,3,5-triazine and the separation membrane of Example 1 show that when heated to 800°C in a nitrogen environment, GO has the best thermal stability, which is significantly better than DADT. Even when heated to 800°C, 51.3% of DADT is still retained, while the separation membrane of Example 1 still has 19.7% of DADT retained when heated to 800°C, indicating that a large amount of DADT is combined with GO.

[0090] like Figure 7 and Figure 8 As shown, Figure 7 is the X-ray photoelectron spectrum of graphene oxide, Figure 8 This is the X-ray photoelectron spectrum of the separation membrane of Example 1. GO and the separation membrane of Example 1 were separated at C1s. It can be seen that compared with GO, the C=O, CO, and -COOH of the separation membrane of Example 1 are significantly reduced. At the same time, the separation membrane of Example 1 has an additional -CN bond, indicating that DADT and GO are effectively connected together through the CN bond.

[0091] Example 2

[0092] Example 2 provides a separation membrane. The preparation method of the separation membrane includes: steps (1B) to (3B).

[0093] Step (1B): At 45°C, add 9.24g of cyanuric chloride powder into a three-necked flask, then slowly add 76mL of refrigerated acetone and 80mL of refrigerated deionized water, and stir magnetically to form a uniform suspension. During this process, keep the temperature at 45°C and add 1mol·L -1 , 108 mL of ammonia water was slowly added dropwise to the above suspension, and then the temperature was maintained at 45 ° C for 30 minutes, and then the temperature was quickly raised to 65 ° C for another 30 minutes. After the reaction, the solid at the bottom of the three-necked flask was taken out and filtered. The filter cake was repeatedly rinsed with deionized water and then dried in a blast oven at 45 ° C to obtain 4.2 g of 2,4-diamino-6-chloro-1,3,5-triazine (DACT).

[0094] Step (2B): 4.2 g of DACT was dissolved in 200 mL of 1,4-dioxane, 16.2 g of octadecylamine was added, and 2 g of sodium carbonate was added as an acid scavenger. The mixture was then refluxed at 90° C. for 6 h. After the reaction, the solid product was filtered, the filter cake was rinsed with a large amount of deionized water, and the filter cake was recrystallized from ethanol to obtain approximately 9.3 g of 2,4-diamino-6-octadecylamine-1,3,5-triazine (DAOT).

[0095] Step (3B): 80 mg of GO was dispersed in 80 mL of dry N,N-dimethylformamide and sonicated for 15 min to obtain a stable suspension. Then, 800 mg of DAOT and 2 mg of HATU were added, and the mixture was heated to 90°C and reacted for 1 h. The mixture was filtered through a polyvinylidene fluoride membrane (pore size = 0.45 μm) to obtain a GO-DAOT solid. The solid was repeatedly washed with deionized water and finally freeze-dried to obtain a separation membrane with a pore size of 1.8 nm to 2.8 nm.

[0096] Example 3

[0097] Example 3 provides a separation membrane. The preparation method of the separation membrane includes: steps (1C) to (3C).

[0098] Step (1C): At 45°C, 9.24 g of cyanuric chloride powder was added to a three-necked flask, followed by the slow addition of 76 mL of refrigerated acetone and 80 mL of refrigerated deionized water. After magnetic stirring, a uniform suspension was formed. During this process, the temperature was maintained at 45°C. 1 mol·L -1, 108 mL of ammonia water was slowly added dropwise to the above suspension, and then the temperature was maintained at 45 ° C for 30 minutes, and then the temperature was quickly raised to 65 ° C for another 30 minutes. After the reaction, the solid at the bottom of the three-necked flask was taken out and filtered. The filter cake was repeatedly rinsed with deionized water and then dried in a blast oven at 45 ° C to obtain 4.2 g of 2,4-diamino-6-chloro-1,3,5-triazine (DACT).

[0099] Step (2C): 4.2 g of DACT was dissolved in 200 mL of 1,4-dioxane, 6.06 g of hexylamine and 2 g of sodium carbonate were added as an acid scavenger, and then refluxed at 90° C. for 6 h. After the reaction, the solid product was filtered, the filter cake was rinsed with a large amount of deionized water, and the filter cake was recrystallized from ethanol to obtain 9.3 g of 2,4-diamino-6-hexylamine-1,3,5-triazine (DAHT).

[0100] Step (3C): 80 mg of GO was dispersed in 80 mL of dry N,N-dimethylformamide and sonicated for 15 min to obtain a stable suspension. Then, 800 mg of DAHT and 2 mg of HATU were added, and the mixture was heated to 90°C and reacted for 1 h. The mixture was filtered through a polyvinylidene fluoride membrane (pore size = 0.45 μm) to obtain a GO-DADT solid. The solid was repeatedly washed with deionized water and finally freeze-dried to obtain a separation membrane with a pore size of 0.8 nm to 1.1 nm.

[0101] Example 4

[0102] Example 4 provides a separation membrane. The preparation method of the separation membrane is the same as that of Example 1, except that the reaction temperature in step (1A) is different. Specifically, at 45°C, 9.24g of cyanuric chloride powder is added to a three-necked flask, and then 76mL of refrigerated acetone and 80mL of refrigerated deionized water are slowly added in sequence. After magnetic stirring, a uniform suspension is formed. During this process, the temperature is maintained at 45°C, and 1mol·L -1 , 108 mL of ammonia water was slowly added dropwise to the above suspension, and then the temperature was maintained at 5 ° C for 30 minutes, and then the temperature was quickly raised to 75 ° C for another 30 minutes. After the reaction, the solid at the bottom of the three-necked flask was taken out and filtered. The filter cake was repeatedly rinsed with deionized water and then dried in a blast oven at 45 ° C to obtain 4.2 g of 2,4-diamino-6-chloro-1,3,5-triazine (DACT).

[0103] Example 5 and Example 6

[0104] Example 5 and Example 6 each provide a separation membrane. The preparation method of the separation membrane is the same as that of Example 1, except that the cyanuric chloride powder in step (1A) is replaced by melamine and thiocyanuric acid, respectively.

[0105] Example 7 to Example 9

[0106] Examples 7 to 9 each provide a separation membrane. The preparation method of the separation membrane is the same as that of Example 1, except that the GO in step (3A) is replaced by carboxylated boron nitride, carboxylated two-dimensional transition metal carbon / nitrogen compound, and carboxylated clay mineral, respectively.

[0107] Example 10 to Example 11

[0108] Examples 10 and 11 each provide a separation membrane. The preparation method of the separation membrane is the same as that of Example 1, except that the dodecylamine in step (2A) is replaced by heptylamine and nonylamine, respectively.

[0109] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A separation membrane, characterized in that include: A main layer having a sheet structure and organic materials distributed between the sheets of the main layer; wherein, The material of the main layer is connected to the organic material via a covalent bond.

2. The separation membrane according to claim 1, wherein The spacing between the sheets of the host layer ranges from 0.8 nm to 2.8 nm.

3. The separation membrane according to claim 1, wherein The material of the main layer includes at least one of graphene oxide, boron nitride, two-dimensional transition metal carbon / nitrogen compounds and clay minerals.

4. The separation membrane according to claim 1, wherein The organic material includes: an organic amine compound.

5. A method for preparing a separation membrane, characterized in that: include: Mixing a main material source, an organic material source and a condensing agent and reacting them; as well as, The reaction product is filtered and dried in sequence to obtain a separation membrane; The separation membrane comprises: a main layer having a sheet structure and an organic material distributed between the sheets of the main layer; wherein the material of the main layer and the organic material are connected via a covalent bond.

6. The method for preparing a separation membrane according to claim 5, wherein: The main material source includes at least one of graphene oxide, carboxylated boron nitride, carboxylated two-dimensional transition metal carbon / nitrogen compounds and carboxylated clay minerals.

7. The method for preparing a separation membrane according to claim 5, wherein: The organic material source includes at least one of 2,4-diamino-6-dodecylamine-1,3,5-triazine, an octadecylamine derivative, and a hexylamine derivative.

8. The method for preparing a separation membrane according to claim 5, wherein: The reaction temperature ranges from 85°C to 90°C; and / or, The reaction time ranges from 0.8 hours to 1.5 hours.

9. The method for preparing a separation membrane according to claim 5, wherein: The preparation method further includes, before mixing the host material source, the organic material source, and the condensing agent and reacting them, preparing the organic material source, including: Adding ammonia water to a solution of a compound containing chlorine or thiocyanate to carry out a reaction; Filtering the product after the reaction to obtain a solid product; mixing the solid product, the aliphatic amine compound and the acid scavenger and reacting them; The product after the reaction is filtered to obtain the organic material source.

10. The method for preparing a separation membrane according to claim 9, wherein: The chlorine- or thiocyanate-containing compound includes at least one of cyanuric chloride, melamine and thiocyanic acid; and / or The aliphatic amine compound includes at least one of hexylamine, dodecylamine, octadecylamine, heptylamine and nonylamine.

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