A method for preparing a multi-channel chabazite molecular sieve membrane

Abstract

The application discloses a preparation method of a multi-channel chabazite zeolite molecular sieve membrane, and high-performance chabazite zeolite molecular sieve membranes are prepared on a multi-channel carrier. The method comprises the following steps: (1) preparation of seed crystals; (2) coating of a seed crystal layer on the multi-channel carrier; and (3) synthesis of the chabazite zeolite molecular sieve membrane by using a secondary growth method. Owing to the multi-channel structure and specific pore characteristics, the multi-channel chabazite zeolite molecular sieve membrane prepared by the application has high selectivity and can accurately separate molecules with different sizes and properties. Meanwhile, the rich transmission paths enable the multi-channel chabazite zeolite molecular sieve membrane to have high flux, greatly improve the permeation rate of substances, and significantly enhance the processing capacity compared with a single-channel molecular sieve membrane.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing a multi-channel chabazite molecular sieve membrane, and belongs to the technical field of molecular sieve membrane material preparation. BACKGROUND

[0002] In industry, ethanol is usually purified by azeotropic distillation or extractive distillation. These methods have large energy consumption and complex operation. Compared with traditional separation processes such as distillation and extraction, membrane separation technology has attracted more and more attention due to its small footprint, simple operation and low running cost. As a new type of inorganic membrane material, zeolite molecular sieve membrane has the general characteristics of inorganic membrane, such as good thermal stability, good chemical stability, high mechanical strength and corrosion resistance, and also has the inherent characteristics of zeolite molecular sieve, such as uniform pore size, strong stability, adjustable pore size and chemical properties, etc. It is an ideal membrane separation material and has a wide application prospect in the separation of liquid mixtures. Chabazite molecular sieve membrane has a chabazite-type 8-membered ring pore structure, and its 8-membered ring pore size is 0.38 nm x 0.38 nm, which can be used to separate water (0.265 nm) from ethanol (0.43 nm).

[0003] NaA molecular sieve membrane has been used for alcohol-water separation and has shown high selective separation capacity. It has good effect on alcohol-water separation, especially in the dehydration treatment of some specific alcohols such as isopropanol. It has good mechanical strength and thermal stability and can work under certain temperature and pressure conditions. Morigami Y et al. (Morigami Y et al. Separation and Purification Technology, 2001, 25(1-3): 251-260.) reported the first large-scale application of a NaA zeolite molecular sieve membrane in a pervaporation (PV) plant, which had high permeability and high selectivity for water. However, the stability of NaA zeolite molecular sieve membrane in an acidic or strongly basic environment is poor, which may affect its service life and separation performance. Compared with NaA molecular sieve membrane (Si / Al = 1-2), chabazite molecular sieve membrane (Si / Al = 3-5) has a higher silicon-aluminum ratio, and has better stability under harsh conditions such as acidity or high temperature and high pressure, and has a wide application prospect in the dehydration of organic solvents.

[0004] At present, the preparation of chabazite zeolite membrane is mostly on tubular, sheet or hollow fiber, which has small membrane area and low mechanical strength. Multi-channel carrier has larger membrane area, higher mechanical strength and greater packing density. Therefore, the multi-channel chabazite zeolite membrane is more suitable for industrial application of organic solvent dehydration, thereby meeting the market demand for energy saving and emission reduction in this industry. However, it is very difficult to prepare zeolite membrane on multi-channel carrier. The structure of multi-channel carrier is complex, and the crystal seed is difficult to coat uniformly, thereby leading to uneven growth of the membrane layer, defects, and difficulty in repeatedly preparing uniform and dense high-quality zeolite membrane on the carrier.

[0005] CN2013107543150 discloses a high-strength hollow fiber zeolite membrane and a preparation method thereof. The membrane is grown on the outer wall of the hollow fiber. In view of the fragile characteristics of the hollow fiber carrier, a multi-channel hollow fiber configuration is adopted to improve the mechanical strength of the carrier. The multi-channel hollow fiber configuration comprises 3-9 channels, and the outer diameter of the carrier is 2.0-4.0 mm. The preparation method of the zeolite membrane adds water glass in the crystal seed solution to improve the adhesion between the crystal seed and the support. The zeolite crystal seed can be NaA, T-type or MFI-type zeolite, but the preparation of chabazite zeolite membrane and its performance are not disclosed. Since the membrane is grown on the outer wall of the carrier, the increase in the number of channels cannot increase the effective area of the membrane. SUMMARY

[0006] In view of the above shortcomings, the purpose of the present application is to provide a preparation method of multi-channel chabazite zeolite membrane, and to prepare high-quality chabazite zeolite membrane on a multi-channel carrier. The membrane layer is continuous and dense, and exhibits excellent separation performance for ethanol / water mixture.

[0007] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0008] A preparation method of multi-channel chabazite zeolite membrane, comprising the following steps:

[0009] (1) Crystal seed preparation: mixing silicon source, aluminum source, alkali source, organic structure directing agent OSDA and deionized water in proportion, stirring and aging to form a sol with a molar ratio of SiO2 / Al2O3=10-500, Na2O / SiO2=0.01-0.4, OSDA / SiO2=0.05-1.0 and H2O / SiO2=20-400; hydrothermal synthesis of the sol at a temperature of 100-200℃, and then washing and drying after the reaction to obtain a zeolite crystal seed;

[0010] (2) Multi-channel carrier coating crystal seed: adding the zeolite crystal seed prepared in step (1) into a solvent, and obtaining a crystal seed suspension by ultrasonic treatment; coating the crystal seed on the inner wall of the pretreated multi-channel carrier using the crystal seed suspension, and forming a crystal seed layer on the surface of the multi-channel carrier after drying.

[0011] (3) Preparation of the multi-channel chabazite zeolite membrane: mixing a silicon source, an aluminum source, sodium fluoride, cesium hydroxide, a polydiallyldialkylammonium salt PDDA, an alkali source and water, stirring and aging to form a sol with a molar ratio of Si02 / Al203=2-50, Na20 / Si02=0.03-0.4, H20 / Si02=20-150, PDDA / Si02=0.02-0.3, CsOH / Si02=0.01-1, and NaF / Si02=0.1-5; placing the multi-channel carrier with the seed layer coated obtained in step (2) into a reaction kettle containing the sol, and hydrothermally synthesizing at a temperature of 100-200°C, and after the reaction, washing and drying to obtain the chabazite zeolite membrane.

[0012] Preferably, the organic structure directing agent OSDA in step (1) is selected from one of N,N,N-trimethyladamantylammonium hydroxide, N,N,N-trimethyladamantylammonium bromide, N,N,N-trimethyladamantylammonium iodide, N,N,N-trimethylbenzylammonium hydroxide, N,N,N-trimethylbenzylammonium bromide, N,N,N-trimethylbenzylammonium iodide or tetraethylammonium hydroxide.

[0013] Preferably, the aluminum source in steps (1) and (3) is selected from one of aluminum hydroxide, sodium metaaluminate, aluminum phyllosilicate, aluminum isopropoxide, aluminum n-butylate, aluminum foil, aluminum powder or aluminum oxide.

[0014] Preferably, the silicon source in steps (1) and (3) is selected from one of silica sol, tetraethyl orthosilicate, tetramethyl orthosilicate, sodium silicate, water glass or silicon powder.

[0015] Preferably, the alkali source in steps (1) and (3) is selected from sodium hydroxide or potassium hydroxide.

[0016] Preferably, in steps (1) and (3), the stirring and aging time is 1-24h.

[0017] Preferably, in steps (1) and (3), the hydrothermal synthesis reaction time is 10-144h.

[0018] Preferably, in step (2), the method for pretreating the multi-channel carrier is to ultrasonically treat, wash and dry the multi-channel carrier, then glaze both ends thereof, and dry and calcine after glazing.

[0019] Preferably, the material of the multi-channel carrier in step (2) is aluminum oxide, mullite, silicon carbide or silicon oxide.

[0020] Preferably, the average pore size of the multi-channel carrier in step (2) is 50-2000 nm, the porosity is 30%-60%, the inner diameter of each channel is 2-6 mm, the outer diameter is 20-40 mm, and the tube length is 50-1000 mm.

[0021] Preferably, the mass concentration of the seed crystal suspension in step (2) is 0.03wt%-1wt%, preferably the concentration is 0.05wt%-0.5wt%; the solvent is one or more of water, ethanol or isopropanol.

[0022] Preferably, the seed crystal coating method in step (2) is dip coating, the time is 30-90 s, and the number of dip coating is 1-3 times.

[0023] Preferably, the polydiallyl dialkyl ammonium salt in step (3) is selected from polydiallyl dimethyl ammonium chloride, polydiallyl dimethyl ammonium bromide, polydiallyl dimethyl ammonium hydroxide, polydiallyl dimethyl ammonium iodide, polydiallyl diethyl ammonium chloride, polydiallyl dipropyl ammonium chloride, polydiallyl diethyl ammonium hydroxide, polydiallyl dipropyl ammonium hydroxide, polydiallyl diethyl ammonium bromide or polydiallyl dipropyl ammonium bromide.

[0024] The preparation method of the multi-channel chabazite zeolite membrane of the present application adds cesium hydroxide as a mineralizer to promote the hydrolysis reaction of the silicon source and the aluminum source, so that the silicon and aluminum species in the reaction system are more likely to form the structural units of the zeolite, and the growth of the membrane layer is promoted. The polydiallyl dialkyl ammonium salt plays both a charge adjusting role and a nucleation induction role. It improves the stability of the membrane by changing the charge properties of the system. At the same time, it also helps to control the formation of the structure of the membrane, promotes the growth of a specific crystal structure or morphology, and a continuous and dense chabazite zeolite membrane is prepared on the multi-channel carrier.

[0025] Beneficial effects: According to the preparation method of the multi-channel chabazite zeolite membrane of the present application, a membrane synthesis sol containing sodium fluoride is used instead of a sol containing an organic template agent to prepare a chabazite zeolite membrane without adding an organic structure directing agent. Through the action of cesium hydroxide and polydiallyl dialkyl ammonium salt, a continuous and dense chabazite zeolite membrane is prepared on the multi-channel carrier, and problems such as membrane cracking caused by the subsequent removal process of the organic template agent are avoided. The multi-channel chabazite zeolite membrane layer prepared by the method of the present application is uniform and dense. With its multi-channel structure and specific pore characteristics, the membrane has high selectivity and can accurately separate molecules of different sizes and properties. At the same time, the abundant transmission path makes it have high throughput, greatly improving the transmission rate of substances. Compared with single-channel zeolite membranes, the processing capacity is significantly enhanced, and the membrane has high packing density, mechanical strength, selectivity and high throughput, can significantly reduce the volume of the membrane module and the cost, has excellent separation performance for ethanol / water mixtures, and is conducive to the industrial application of the membrane product.

[0026] (1) The present application is prepared on a multi-channel carrier, which greatly increases the surface area to volume ratio of the membrane compared with the traditional single-channel carrier, significantly improves the packing density of the membrane, i.e. significantly reduces the volume of the membrane module, greatly simplifies the design and manufacturing cost of the membrane module, and also significantly improves the mechanical strength of the membrane, enhances the fluid pressure resistance, and is suitable for separation applications in high-pressure fluid environment.

[0027] (2) The present application is prepared on a multi-channel carrier, which first uses polydiallyl dialkyl ammonium salt as a nucleation inducer for chabazite membrane, uses cesium hydroxide (CsOH) as a mineralizer, and uses the epitaxial growth of high-silicon SSZ-13 seed crystals to prepare a multi-channel chabazite zeolite membrane. Since the polydiallyl dialkyl ammonium salt does not enter the molecular sieve channel, it is not necessary to remove the nucleation inducer by an additional calcination step. After pervaporation test, it shows high water separation selectivity and permeation rate, and also has good hydrothermal stability. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 (a) is a schematic diagram of a 19-channel carrier; (b) is a schematic diagram of three different position channels (C1-C3) of a 19-channel molecular sieve membrane;

[0029] Figure 2 XRD diffraction pattern of the molecular sieve seed crystals synthesized in Example 1;

[0030] Figure 3 SEM image of the 19-channel chabazite molecular sieve membrane synthesized in Example 1;

[0031] Figure 4 XRD diffraction pattern of the 19-channel chabazite molecular sieve membrane synthesized in Example 1;

[0032] Figure 5 PV test performance diagram of the 19-channel chabazite molecular sieve membrane synthesized in Example 1, wherein (a) is a diagram of flux and separation factor versus water content, and (b) is a diagram of flux and separation factor versus temperature;

[0033] Figure 6 Stability test diagram of the 19-channel chabazite molecular sieve membrane synthesized in Example 1. DETAILED DESCRIPTION

[0034] In order to further describe the present application, specific examples for implementing the present application are given below, but the scope of the present application claimed is not limited to the examples.

[0035] Example 1

[0036] The preparation method of the multi-channel chabazite molecular sieve membrane is as follows:

[0037] (1) Preparation of seeds

[0038] The organic structure directing agent N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdaOH, Sigma-Aldrich, 25%), deionized water and aluminum hydroxide were mixed in a certain ratio, stirred at room temperature for about 1 h, then the silicon source (TM-40, Sigma-Aldrich, 40%) was added and stirring was continued for 6 h. The molar ratio of the components of the formed sol was: SiO2 / Al2O3=100, Na2O / SiO2=0.1, OSDA / SiO2=0.6, H2O / SiO2=40. Subsequently, the sol was poured into a stainless steel reactor with a tetrafluoroethylene liner, placed in a constant temperature oven at 160°C for 72 h. After the reaction was completed, the stainless steel reactor was removed and placed in cold water to cool, then the milky white solid particles in the liner were poured out and washed with deionized water by centrifugation for 3 times. Drying was carried out at 60°C to obtain the molecular sieve seed crystals for later use.

[0039] (2) Coating of seeds with a multi-channel support

[0040] The molecular sieve seed crystals obtained in step (1) were dispersed in ethanol and ultrasonically treated for 2 h to prepare a 0.2 wt% seed crystal suspension. A 19-channel porous alumina support was used, with an average pore size of 100 nm, an outer diameter of the membrane tube of 30 mm, an inner diameter of the individual channels of 3.5 mm, and a tube length of 60 mm. First, the multi-channel support was ultrasonically treated, washed and dried, then glazed at both ends, dried and calcined. Then, a heat shrink tube of appropriate size was used for heat shrink treatment of the multi-channel support (so that the seed crystals are only coated on the inner wall of the multi-channel support during dip coating), the multi-channel support was immersed in the seed crystal suspension for 30-60 s, then the support was slowly taken out of the seed crystal suspension, and finally dried at 60°C for 2 h to form a continuous and dense seed crystal layer on the surface of the multi-channel support.

[0041] (3) Preparation of a multi-channel chabazite molecular sieve membrane

[0042] A solution was prepared by mixing polydiallyldimethylammonium chloride (PDDA), sodium hydroxide (NaOH, 98 wt%), cesium hydroxide solution (CsOH, 50 wt%) and deionized water in a certain ratio and stirring for 15 min at room temperature. Then, aluminum hydroxide [Al(OH)3, 99 wt%], silica sol (40 wt% aqueous solution) and sodium fluoride were added to the solution and stirred until clear. The solution was cooled to room temperature and aged for 24 h to obtain a sol with the molar ratio of PDDA / SiO2=0.2, SiO2 / Al2O3=3, Na2O / SiO2=0.25, H2O / SiO2=60, CsOH / SiO2=0.07 and NaF / SiO2=0.27. The multi-channel support coated with the seed layer in step (2) was placed in a stainless steel reactor containing the sol and reacted at 135°C for 48 h. The membrane after reaction was washed and air-dried at room temperature.

[0043] Figure 1 (a) is a schematic diagram of the structure of a 19-channel support; (b) is a schematic diagram of the channels at three different positions of a 19-channel molecular sieve membrane, which are peripheral channels (C1), sub-peripheral channels (C2) and central channels (C3), respectively. The XRD diffraction of the molecular sieve seed crystals synthesized in step (1) is shown in Figure 2 wherein the intensity of the CHA characteristic peaks is uniform, indicating that the growth of the membrane is uniform in different channels and the membrane is pure CHA phase. Figure 3 The SEM images of the surface and section of the peripheral channels (a, b), sub-peripheral channels (c, d) and central channels (e, f) of the 19-channel chabazite molecular sieve membrane prepared by reacting for 48 h are shown in the figure. It can be observed from the figure that the thickness of the membrane layer in the three channels is between 6.8 and 7.1 μm, the membrane layer is uniform and dense, and the crystal morphology is similar.

[0044] Figure 4 The XRD diffraction patterns of different channels of the 19-channel chabazite molecular sieve membrane prepared by reacting for 48 h are shown in the figure, wherein (a) is the XRD diffraction pattern of the support, (b) is the XRD diffraction pattern of the peripheral channels, (c) is the XRD diffraction pattern of the sub-peripheral channels and (d) is the XRD diffraction pattern of the central channels. It can be known from the analysis of the XRD diffraction patterns that each channel corresponds to the characteristic peaks of CHA.

[0045] (4) Ethanol / water solution separation performance test

[0046] The liquid separation performance of the membrane can be represented by two parameters, i.e. liquid permeation flux J and separation coefficient a. The liquid permeation flux J represents the mass of liquid passing through unit area of the membrane per unit time, J = M / (A x t), with the unit of kg / (m 2 h); the separation coefficient a is used to evaluate the separation efficiency of the membrane, a = (y i / y j ) / (xi x j y i y j x i x j The mass fraction of component i (water), j (organic substance) in the permeate (y) and the feed (x).

[0047] Test conditions: temperature 75°C, pressure on the permeate side maintained at 0.103 MPa, feed composition 90 wt% ethanol and 10 wt% water, feed liquid flow rate 0.6 L / min. The composition of the liquid on the permeate side was analyzed using a gas chromatograph. The results are shown in Table 1.

[0048] Example 2

[0049] The method for preparing the multi-channel chabazite molecular sieve membrane is as follows:

[0050] Step (1): The organic structure directing agent N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdaOH, Sihma-Aldrich, 25%), deionized water and aluminum hydroxide were mixed in a certain ratio, stirred at room temperature for about 1 h, then the silicon source (TM-40, Sigma-Aldrich, 40%) was added and stirring was continued for 6 h. The molar ratio of the components of the formed sol was: SiO2 / Al2O3 = 10-500, Na2O / SiO2 = 0.01-0.4, OSDA / SiO2 = 0.05-1.0, H2O / SiO2 = 20-400. Subsequently, the sol was poured into a stainless steel reaction kettle with a tetrafluoroethylene liner, placed in a constant temperature oven at 160°C and reacted for 48 h. After the reaction was complete, the stainless steel reaction kettle was removed and placed in cold water to cool, then the milky white solid particles in the liner were poured out and washed 3 times by centrifugation with deionized water. Drying was carried out at 60°C to obtain the molecular sieve crystal seeds for later use.

[0051] Step (2): The same as in Example 1, except that the concentration of the crystal seed suspension was 0.15 wt%.

[0052] Step (3): Similar to Example 1, except that in the sol, PDDA / SiO2 = 0.02, CsOH / SiO2 = 0.01, NaF / SiO2 = 0.1.

[0053] Step (4): The ethanol / water solution separation performance was tested according to the method of Example 1, and the test temperature was 110°C. The results are shown in Table 1.

[0054] Example 3

[0055] The method for preparing the multi-channel chabazite molecular sieve membrane is as follows:

[0056] Step (1): The same as the process of Example 2.

[0057] Step (2): The same as the process of Example 1, except that the concentration of the seed suspension was 0.15 wt%.

[0058] Step (3): Similar to Example 1, except that the PDDA / SiO2=0.3, CsOH / SiO2=1, NaF / SiO2=5 in the sol, the reaction temperature was 150°C, and the reaction time was 48 h.

[0059] Step (4): The ethanol / water separation performance was tested according to the method of Example 1, and the test temperature was 90°C. The results are shown in Table 1.

[0060] Example 4

[0061] The preparation method of the multi-channel chabazite molecular sieve membrane is as follows:

[0062] Step (1): The same as the process of Example 2.

[0063] Step (2): The same as the process of Example 1, except that the concentration of the seed suspension was 0.15 wt%.

[0064] Step (3): Similar to Example 1, except that the PDDA / SiO2=0.2, CsOH / SiO2=0.5, NaF / SiO2=3 in the sol, the reaction temperature was 150°C, and the reaction time was 32 h.

[0065] Step (4): The ethanol / water separation performance was tested according to the method of Example 1, and the test temperature was 75°C. The results are shown in Table 1.

[0066] Example 5

[0067] The preparation method of the multi-channel chabazite molecular sieve membrane is as follows:

[0068] Step (1): The same as the process of Example 2.

[0069] Step (2): The same as the process of Example 1.

[0070] Step (3): Similar to Example 1, except that the SiO2 / Al2O3=10, H2O / SiO2=50 in the sol, the reaction temperature was 140°C, and the reaction time was 48 h.

[0071] Step (4): The ethanol / water separation performance was tested according to the method of Example 1, and the test temperature was 105°C. The results are shown in Table 1.

[0072] Example 6

[0073] A method for preparing a multi-channel chabazite zeolite membrane is as follows:

[0074] Step (1): The same as in Example 2.

[0075] Step (2): The same as in Example 1.

[0076] Step (3): The same as in Example 1, except that the SiO2 / Al2O3 ratio in the sol is 50, the H2O / SiO2 ratio is 150, the aging time is 28 h, the reaction temperature is 165°C, and the reaction time is 48 h.

[0077] Step (4): The ethanol / water separation performance of the prepared multi-channel chabazite zeolite membrane is tested according to the method of Example 1, and the test temperature is 85°C. The results are shown in Table 1.

[0078] Example 7

[0079] The prepared multi-channel chabazite zeolite membrane is subjected to a pervaporation experiment according to the method of Example 1. The performance of the multi-channel chabazite zeolite membrane is tested by changing the water content in the raw material composition and the test temperature, respectively. Figure 5 (a) It can be seen that the water flux increases with the increase of water content, and the separation coefficient remains stable. The test temperatures are 75°C, 90°C, 105°C and 120°C, respectively, and Figure 5 (b) It can be seen that the water flux increases with the increase of temperature, and the separation coefficient also increases with the increase of temperature.

[0080] Example 8

[0081] The prepared multi-channel chabazite zeolite membrane is subjected to a pervaporation experiment according to the method of Example 1. The test temperature is 120°C, and the ethanol / water separation performance is tested for 72 h continuously. Figure 6 It can be seen that the water flux and the water content in the permeate remain basically stable within 72 h.

[0082] Comparative Example 1

[0083] A method for preparing a chabazite zeolite membrane is as follows:

[0084] Step (1): The same as in Example 1.

[0085] Step (2): The same as in Example 1, except that the carrier used is a single-channel, and the seed crystals are applied to the surface of the carrier by rubbing and coating, and then dried in a 60°C oven for 2 h.

[0086] Step (3): The same as in Example 1.

[0087] Step (4): The separation performance of its ethanol / water solution was tested according to the method of Example 1, and the results are shown in Table 1.

[0088] Comparative Example 2

[0089] The preparation method of the chabazite molecular sieve membrane is as follows:

[0090] Step (1): The same as the process of Example 1.

[0091] Step (2): Similar to Example 1. The difference is that the support used is a single channel, and the seed is coated on the surface of the support by dip coating, and then dried in a 60°C oven for 2h. The concentration of the seed suspension is 0.1wt%.

[0092] Step (3): The same as Example 1.

[0093] Step (4): The separation performance of its ethanol / water solution was tested according to the method of Example 1, and the results are shown in Table 1.

[0094] Comparative Example 3

[0095] The preparation method of the chabazite molecular sieve membrane is as follows:

[0096] Step (1): The same as the process of Example 1.

[0097] Step (2): The same as the process of Example 1.

[0098] Step (3): Similar to Example 1, except that cesium hydroxide is not added when the sol is configured.

[0099] Step (4): The separation performance of its ethanol / water solution was tested according to the method of Example 1, and the results are shown in Table 1.

[0100] Comparative Example 4

[0101] The preparation method of the chabazite molecular sieve membrane is as follows:

[0102] Step (1): The same as the process of Example 1.

[0103] Step (2): The same as the process of Example 1.

[0104] Step (3): Similar to Example 1, except that polydiallyldimethylammonium chloride (PDDA) is not added when the sol is configured.

[0105] Step (4): The separation performance of its ethanol / water solution was tested according to the method of Example 1, and the results are shown in Table 1.

[0106] Table 1 Separation performance test of examples

[0107]

Claims

1. A method for preparing a multi-channel chabazite zeolite membrane, comprising the following steps: (1) Seed crystal preparation: mixing a silicon source, an aluminum source, an alkali source, an organic structure directing agent OSDA and deionized water, stirring and aging to form a sol with a molar ratio of SiO 2 / Al 2O 3=10-500, Na 2O / SiO 2=0.01-0.4, OSDA / SiO 2=0.05-1.0 and H 2O / SiO 2=20-400; hydrothermally synthesizing the sol at a temperature of 100-200 ℃, and obtaining a zeolite seed crystal after cleaning and drying; (2) Multi-channel carrier coating seed crystal: adding the zeolite seed crystal prepared in step (1) into a solvent, and obtaining a seed crystal suspension by ultrasonic treatment; coating the seed crystal in the inner wall of a pretreated multi-channel carrier using the seed crystal suspension, and forming a seed crystal layer on the surface of the multi-channel carrier after drying; the multi-channel carrier has an inner diameter of 2-6 mm, an outer diameter of 20-40 mm and a tube length of 50-1000 mm; (3) Multi-channel chabazite zeolite membrane preparation: mixing a silicon source, an aluminum source, sodium fluoride, cesium hydroxide, a polydiallyldialkylammonium salt PDDA, an alkali source and water, stirring and aging to form a sol with a molar ratio of SiO 2 / Al 2O 3=2-50, Na 2O / SiO 2=0.03-0.4, H 2O / SiO 2=20-150, PDDA / SiO 2=0.02-0.3, CsOH / SiO 2=0.01-1 and NaF / SiO 2=0.1-5; placing the multi-channel carrier with the coated seed crystal layer obtained in step (2) in a reaction kettle containing the sol, and hydrothermally synthesizing at a temperature of 100-200 ℃, and obtaining a chabazite zeolite membrane after cleaning and drying.

2. The method of making a multi-channel chabazite zeolite membrane according to claim 1, wherein, The aluminum source in steps (1) and (3) is aluminum hydroxide, sodium metaaluminate, aluminum trihydrate, aluminum isopropoxide, aluminum n-butylate, aluminum foil, aluminum powder or aluminum oxide.

3. The method of making a multi-channel chabazite molecular sieve membrane according to claim 1, wherein, The silicon source in steps (1) and (3) is silica sol, tetraethyl orthosilicate, tetramethyl orthosilicate, sodium silicate, water glass or silicon powder.

4. The method of claim 1, wherein the method is characterized by: In steps (1) and (3), the stirring and aging time is 1-24 h, and the hydrothermal synthesis reaction time is 10-144 h.

5. The method of making a multi-channel chabazite molecular sieve membrane according to claim 1, wherein, The seed crystal coating method in step (2) is dip coating.

6. The method of making a multi-channel chabazite molecular sieve membrane according to claim 1, wherein, The multi-channel carrier material in step (2) is aluminum oxide, mullite, silicon carbide or silicon oxide.

7. The method of claim 1, wherein the method is characterized by: The average pore size of the multi-channel carrier in step (2) is 50-2000 nm, and the porosity is 30%-60%.

8. The method of claim 1, wherein the multiple-channel chabazite molecular sieve membrane is prepared by the steps of: The mass concentration of the seed crystal suspension in step (2) is 0.03-1 wt%; and the solvent is one or more of water, ethanol or isopropanol.

9. The method of claim 1, wherein the method is characterized by: In step (2), the pretreatment method of the multi-channel carrier is ultrasonic treatment, washing and drying, then glazing at both ends, drying and calcining.

10. The method of making a multi-channel chabazite zeolite membrane of claim 1, wherein, The polydiallyldialkylammonium salt in step (3) is polydiallyldimethylammonium chloride, polydiallyldimethylammonium bromide, polydiallyldimethylammonium hydroxide, polydiallyldimethylammonium iodide, polydiallyldiethylammonium chloride, polydiallyldipropylammonium chloride, polydiallyldiethylammonium hydroxide, polydiallyldipropylammonium hydroxide, polydiallyldiethylammonium bromide, or polydiallyldipropylammonium bromide. The polydiallyldialkylammonium salt in step (3) is polydiallyldimethylammonium chloride, polydiallyldimethylammonium bromide, polydiallyldimethylammonium hydroxide, polydiallyldimethylammonium iodide, polydiallyldiethylammonium chloride, polydiallyldipropylammonium chloride, polydiallyldiethylammonium hydroxide, polydiallyldipropylammonium hydroxide, polydiallyldiethylammonium bromide, or polydiallyldipropylammonium bromide.

Images