Molecular sieve SSZ-39 with AEI skeleton and preparation method and application thereof

Abstract

The invention discloses a molecular sieve SSZ-39 with an AEI framework and a preparation method and application thereof, and belongs to the technical field of molecular sieves. The method comprises the following steps: S1, mixing raw materials containing a silicon source, an aluminum source, an organic template agent N, N-dimethyl-3, 5-dimethyl piperidine hydroxide, an FAU zeolite precursor solution and deionized water to obtain initial reaction gel; s2, heating and crystallizing the initial reaction gel under a closed condition to obtain a crystallized product; and S3, separating, washing and drying the crystallized product to obtain the SSZ-39 zeolite molecular sieve. The method is simple and easy to operate and low in cost, the obtained product is high in purity and regular in morphology, and the selective adsorption separation effect on C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4 and CO2 / N2 is excellent.

Description

Technical Field

[0001] This application belongs to the technical field of molecular sieves, and particularly relates to a molecular sieve SSZ-39 with an AEI framework, its preparation method and application. Background Art

[0002] In 1999, Zones et al. first reported the synthesis of a silicoaluminate zeolite molecular sieve with an AEI topological structure and named it SSZ-39. In the structure of the SSZ-39 molecular sieve, double six-membered ring (d6r) building units are connected through four-membered rings in the same arrangement to form a two-dimensional plane. Adjacent two-dimensional planes are stacked along the c-axis after rotating 180°, and such a connection method forms a pear-shaped cage cavity with side openings and linear eight-membered ring channels, and the pore size is These structural characteristics make the SSZ-39 molecular sieve an excellent small molecule shape-selective reactor, and it exhibits excellent catalytic performance in various reactions such as selective catalytic reduction of nitrogen oxides (SCR), methanol to olefins (MTO), and NOx adsorption (PNA).

[0003] Different from conventional silicoaluminate zeolite molecular sieves, the synthesis of SSZ-39 zeolite molecular sieves usually requires using one of USY, ZSM-5, and Beta as a precursor, and is synthesized by a topotactic transformation method, or by adding SSZ-39 seeds to the initial reaction gel system for synthesis, which greatly increases the synthesis cost. In recent years, people have been looking for a simpler, easier and cheaper synthesis method to synthesize SSZ-39.

[0004] The literature Advances in the synthesis and application of the SSZ-39zeolite(Inorganic Chemistry Frontiers.,2022;9:1047-57) reports a series of synthesis methods of the silicoaluminum zeolite molecular sieve SSZ-39 with an AEI framework structure. The synthesis process requires using USY / ZSM-5 / Beta as a precursor for topotactic transformation or adding SSZ-39 seeds to the initial gel to obtain a pure phase SSZ-39 product. Summary of the Invention

[0005] In view of this, this application provides a molecular sieve SSZ-39 with an AEI framework, its preparation method and application, and the main purpose is to solve the technical problem of the complex synthesis method of the molecular sieve SSZ-39.

[0006] On the one hand, this application provides a preparation method of a molecular sieve SSZ-39 with an AEI framework, and the method includes the following steps:

[0007] S1: Mix the raw materials including silicon source I, aluminum source I, organic template agent, FAU zeolite precursor solution and deionized water I to obtain an initial gel;

[0008] Among them, the organic template agent is selected from N,N-dimethyl-3,5-dimethylpiperidinium hydroxide;

[0009] The FAU zeolite precursor solution is obtained by mixing and aging the raw materials including aluminum source II, silicon source II, inorganic base and water II;

[0010] S2: Heat and crystallize the initial gel in step S1 under closed conditions to obtain a crystallized product;

[0011] S3: Separate, wash and dry the crystallized product in step S2 to obtain the SSZ-39 zeolite molecular sieve.

[0012] In this application, the FAU zeolite precursor solution provides all the inorganic base sources and part of the silicon source, aluminum source and water required for the reaction system.

[0013] The preparation method provided by this application does not require other zeolite molecular sieves as precursors and does not require the addition of SSZ-39 seeds. This synthesis method is simple and easy to operate, and the synthesized SSZ-39 zeolite molecular sieve has high purity and can be used for the selective adsorption separation of C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4, CO2 / N2.

[0014] Optionally, in step S1, the molar ratio of silicon source (silicon source I + silicon source II), aluminum source (aluminum source I + aluminum source II), inorganic base, FAU zeolite precursor solution, organic template agent and water (water I + water II) in the initial gel is:

[0015] Al2O3 / SiO2 = 0.01 - 0.05;

[0016] NaOH / SiO2 = 0.1 - 0.7;

[0017] H2O / SiO2 = 5 - 30;

[0018] R / SiO2 = 0.1 - 0.5;

[0019] Among them, the molar number of the silicon source is calculated as the molar number of SiO2, the molar number of the aluminum source is calculated as the molar number of Al2O3, the molar number of the inorganic base is calculated as the molar number of sodium ions in the FAU zeolite precursor solution, the molar number of the organic template agent is calculated as the molar number of R, and the molar number of water is calculated as the molar number of H2O itself.

[0020] In the present application, a part of the silicon source, aluminum source, and water in the initial gel comes from the FAU precursor solution, and a part comes from external addition.

[0021] Optionally, the organic templating agent is selected from N,N-dimethyl-3,5-dimethylpiperidinium hydroxide.

[0022] Optionally, in step S1, the molar ratio of Al2O3 / SiO2 in the initial gel is selected from any value of 0.01, 0.02, 0.03, 0.04, 0.05 or the range value between any two of them;

[0023] The molar ratio of NaOH / SiO2 is selected from any value of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or the range value between any two of them;

[0024] The molar ratio of H2O / SiO2 is selected from any value of 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30 or the range value between any two of them;

[0025] The molar ratio of R / SiO2 is selected from any value of 0.1, 0.2, 0.3, 0.4, 0.5 or the range value between any two of them.

[0026] Optionally, in step S1, the molar ratio of the silicon source, aluminum source, inorganic base, and water in the FAU zeolite precursor solution is:

[0027] Al2O3 / SiO2 = 0.05 - 0.1;

[0028] NaOH / SiO2 = 1.2 - 2.0;

[0029] H2O / SiO2 = 10 - 20;

[0030] Wherein, the molar number of water is calculated based on the molar number of H2O itself, the molar number of the silicon source is calculated based on the molar number of SiO2, the molar number of the aluminum source is calculated based on the molar number of Al2O3, and the molar number of the inorganic base is calculated based on the molar number of sodium ions.

[0031] Optionally, in step S1, the molar ratio of Al2O3 / SiO2 in the FAU zeolite precursor solution is selected from any value of 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 or the range value between any two of them;

[0032] The molar ratio of NaOH / SiO2 is selected from any value of 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 or the range value between any two of them;

[0033] The molar ratio of H2O / SiO2 is selected from any value among 10, 12, 15, 18, 20 or the range value between any two of them.

[0034] Optionally, in step S1, the preparation process of the FAU zeolite precursor solution includes: mixing raw materials containing an aluminum source, an inorganic base, water and a silicon source, and aging to obtain the FAU zeolite precursor solution.

[0035] Optionally, the preparation process of the FAU zeolite precursor solution in step S1 includes: mixing raw materials containing an aluminum source, an inorganic base and water, stirring until the aluminum source is completely dissolved, adding the silicon source, continuing to stir until a clear and transparent solution is obtained, and aging at a temperature of 20 - 80 °C for 6 - 24 hours to obtain the FAU zeolite precursor solution.

[0036] Optionally, the aging temperature is selected from 20, 30, 40, 50, 60, 70, 80 °C; the aging time is selected from any value among 6h, 10h, 15h, 20h, 24h or the range value between any two of them.

[0037] Optionally, the silicon source in the initial reaction gel is selected from at least one of silica white, silica sol, chromatography silica gel, water glass and tetraethyl orthosilicate.

[0038] Optionally, the silicon source in the FAU zeolite precursor solution is selected from at least one of silica white, silica sol, chromatography silica gel, water glass and tetraethyl orthosilicate.

[0039] Optionally, the aluminum source in the initial reaction gel is selected from at least one of aluminum salts, aluminates, activated alumina, aluminum hydroxide, pseudo - boehmite, aluminum isopropoxide and aluminum n - butoxide.

[0040] Optionally, the aluminum source in the FAU zeolite precursor solution is selected from at least one of aluminum salts, aluminates, activated alumina, aluminum hydroxide, pseudo - boehmite, aluminum isopropoxide and aluminum n - butoxide.

[0041] Optionally, in step S2, the conditions for hydrothermal crystallization include:

[0042] Crystallization temperature: 130 - 180 °C;

[0043] Crystallization pressure: autogenous pressure;

[0044] Crystallization time: 6 - 120h.

[0045] Optionally, the crystallization temperature is selected from any value among 130, 140, 150, 160, 170, 180 or the range value between any two of them;

[0046] The crystallization time is selected from any value among 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 20 h, 30 h, 40 h, 50 h, 60 h, 70 h, 80 h, 90 h, 100 h, 110 h, 120 h or a range value between any two of them.

[0047] Optionally, the crystallization is dynamic crystallization or static crystallization.

[0048] In a second aspect, the present application provides a molecular sieve SSZ-39 with an AEI framework, which is prepared by the above method.

[0049] Optionally, in the molecular sieve SSZ-39, Si / Al = 7 - 10, and the crystal size is 1 - 5 μm.

[0050] Optionally, the Si / Al in the molecular sieve SSZ-39 is selected from any value among 7, 7.5, 8.0, 8.5, 9.0, 9.5, 10 or a range value between any two of them.

[0051] Optionally, the crystal size is 2 - 5 μm.

[0052] In a third aspect, the present application provides the use of the molecular sieve SSZ-39 with an AEI framework prepared by the above method as a selective adsorbent for light alkanes, light alkenes and carbon dioxide.

[0053] Optionally, the SSZ-39 zeolite molecular sieve is applied to the selective adsorption and separation of mixed gases such as C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4, CO2 / N2.

[0054] Optionally, under the condition of removing the template agent, the SSZ-39 zeolite molecular sieve is mixed with a cation solution, and after ion exchange and calcination, a modified M-SSZ-39 type zeolite molecular sieve is obtained;

[0055] Optionally, the temperature of the ion exchange reaction is 20°C - 100°C, and the time is 2 - 8 h.

[0056] Optionally, the ratio of the mass of the SSZ-39 type zeolite molecular sieve to the volume of the cation solution is 1 g : (20 - 100) mL, and the concentration of the cation solution is 0.2 - 1.0 mol / L.

[0057] Optionally, the cation in the cation solution includes NH4 + , Li + , Na + , K + or Cs + ion solution.

[0058] Optionally, the modified M-SSZ-39 zeolite molecular sieve is used for the selective adsorption separation of mixed gases such as C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4, and CO2 / N2.

[0059] Compared with the prior art, the present application has the following beneficial effects:

[0060] (1) The synthesis method of the present application is simple and feasible, and the prepared SSZ-39 zeolite molecular sieve with an AEI framework structure has high crystallinity and regular morphology; compared with the traditional synthesis methods using transformation and the introduction of seeds, the synthesis cost is effectively reduced.

[0061] (2) The zeolite precursor solution in the present application is simple to prepare and can be stored at room temperature for a long time. Moreover, as the aging time of the precursor solution prolongs, the crystallization time required to obtain the pure-phase SSZ-39 molecular sieve is shorter, greatly saving the synthesis cost of SSZ-39 and shortening the synthesis cycle of the SSZ-39 molecular sieve.

[0062] (3) The SSZ-39 molecular sieve prepared in the present application can be used for the selective adsorption separation of mixed gases such as C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4, and CO2 / N2. The method of the present application not only has important significance for the synthesis and application of the SSZ-39 molecular sieve with important industrial application prospects, but also can provide a new synthesis method and idea for other molecular sieves that can only be synthesized by transformation. Description of the Drawings

[0063] Figure 1 is the X-ray diffraction pattern of the SSZ-39 products prepared in Examples 1-6 of the present application;

[0064] Figure 2 is the SEM scanning electron micrograph of the SSZ-39 products prepared in Examples 1-6 of the present application;

[0065] (SEM scales are 10μm, 10μm, 10μm, 10μm, 5μm, and 10μm in sequence)

[0066] Figure 3 is the isothermal adsorption curve of the Na-SSZ-39 product prepared in Example 7 of the present application for small molecule gases. Detailed Embodiments

[0067] The present application will be further described below in conjunction with specific embodiments. The following descriptions are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed in the following preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

[0068] Unless otherwise specified, the raw materials in the embodiments of the present application are all purchased through commercial channels and used directly without any special treatment.

[0069] The present application provides a specific preparation method of a silicon-aluminum SSZ-39 zeolite molecular sieve with an AEI framework structure: mixing a silicon source, an aluminum source, an inorganic base source, an organic template agent (N,N-dimethyl-3,5-dimethylpiperidinium hydroxide), a FAU zeolite precursor solution and deionized water, and stirring evenly to obtain an initial reaction gel. The FAU zeolite precursor solution is obtained by mixing and aging raw materials containing an aluminum source, a silicon source, an inorganic base and water; subjecting the initial reaction gel to hydrothermal crystallization to obtain an SSZ-39 zeolite molecular sieve; the temperature of the hydrothermal crystallization is 130-180 °C and the time is 6-120 h.

[0070] As a preference of the above embodiment, mixing the SSZ-39 zeolite molecular sieve and a cation solution, performing an ion exchange reaction and then calcining to obtain a modified M-SAPO-RHO zeolite molecular sieve; the cations in the cation solution include NH4 + 、Li + 、Na + 、K + and Cs + ; the concentration of the cation solution is 0.2-1.0 mol / L.

[0071] In the present application, unless otherwise specified, all raw material components are commercially available products well-known to those skilled in the art.

[0072] As a preference of the above embodiment, the silicon source preferably includes a solid silicon source, sodium silicate, silica sol or white carbon black. The silica content in the silica sol is preferably 30-50 wt%, more preferably 40 wt%; the silica content in the solid silicon source and white carbon black is preferably 100 wt%.

[0073] As a preference of the above embodiment, the aluminum source includes aluminum hydroxide, sodium aluminate, aluminum isopropoxide or pseudo-boehmite.

[0074] As a preference of the above embodiment, the content of the organic template agent N,N-dimethyl-3,5-dimethylpiperidinium hydroxide is 25-40 wt%, and the organic template agent is preferably purchased from Kent Catalysis Co., Ltd.

[0075] There are no special limitations on the water in this application, and the water well-known in the art can be used, such as deionized water, distilled water, ultrapure water or high-purity water.

[0076] As a preference of the above embodiments, the amounts of sodium hydroxide, silicon source, and aluminum source in the initial reaction gel are calculated based on the amounts of Na2O, SiO2, and Al2O3 respectively, and the molar ratios of sodium hydroxide, silicon source, aluminum source, and water are as follows:

[0077] Al2O3 / SiO2 = 0.01 - 0.05;

[0078] NaOH / SiO2 = 0.2 - 0.7;

[0079] H2O / SiO2 = 5 - 30;

[0080] R / SiO2 = 0.1 - 0.5;

[0081] R represents N,N-dimethyl-3,5-dimethylpiperidinium hydroxide.

[0082] The initial reaction gel formula in the present invention is more preferably:

[0083] Al2O3 / SiO2 = 0.015 - 0.045;

[0084] NaOH / SiO2 = 0.2 - 0.5;

[0085] H2O / SiO2 = 5 - 20;

[0086] R / SiO2 = 0.1 - 0.3.

[0087] The molar ratio of the FAU zeolite precursor solution in the present invention is:

[0088] Al2O3 / SiO2 = 0.03 - 0.1;

[0089] NaOH / SiO2 = 1.2 - 2.0;

[0090] H2O / SiO2 = 10 - 20.

[0091] The formula of the FAU zeolite precursor solution in the present invention is more preferably:

[0092] Al2O3 / SiO2 = 0.05 - 0.1;

[0093] NaOH / SiO2 = 1.5 - 2.0;

[0094] H2O / SiO2 = 15 - 20;

[0095] Preferably, as in the above embodiments, the method of mixing sodium hydroxide, silicon source, aluminum source, FAU zeolite precursor solution and water preferably includes the following steps:

[0096] Perform a first mixing of sodium hydroxide, water and aluminum source, and stir at room temperature until a first mixed system is obtained;

[0097] Add the FAU zeolite precursor solution and the organic template agent R into the first mixed system, and stir evenly at room temperature to obtain a second mixed system;

[0098] Add the silicon source to the second mixed system and stir evenly to obtain an initial reaction gel.

[0099] Preferably, as in the above embodiments, the first mixing and the second mixing are independently carried out in a closed container under stirring conditions at room temperature; the stirring speed is 200 - 800 rpm, more preferably 400 - 600 rpm; there is no special limitation on the mixing time in this application, and it is only necessary to ensure that the raw materials are mixed evenly.

[0100] After obtaining the initial reaction gel, in this application, the initial reaction gel is subjected to hydrothermal crystallization to obtain SSZ-39 zeolite molecular sieve; the temperature of hydrothermal crystallization is 140 - 180 °C, more preferably 150 - 180 °C; the time is 6 - 120 h, more preferably 12 - 120 h.

[0101] Preferably, as in the above embodiments, the hydrothermal crystallization method is preferably static crystallization.

[0102] There is no special limitation on the hydrothermal crystallization equipment in this application, and the hydrothermal crystallization equipment well-known to those skilled in the art can be used. In the embodiments of this application, the hydrothermal crystallization is preferably carried out in a hydrothermal reaction kettle.

[0103] After hydrothermal crystallization, this application preferably further includes the following steps:

[0104] Perform solid-liquid separation on the product obtained by hydrothermal crystallization to obtain a solid; dry the solid to obtain SSZ-39 zeolite molecular sieve.

[0105] There is no special limitation on the method of solid-liquid separation in this application, and the solid-liquid separation methods well-known in the art can be used. In the embodiments of this application, the solid-liquid separation is preferably filtration or centrifugation.

[0106] Preferably, as in the above embodiments, the number of water washings is 3 times. Drying is drying by baking; the drying temperature is preferably 75 - 100 °C, more preferably 85 - 100 °C; the drying time is preferably 6 - 24 h, more preferably 8 - 12 h.

[0107] The preparation method provided by this application does not require other zeolite molecular sieve precursors as raw materials or the additional addition of SZZ-39 zeolite molecular sieve precursors as seeds, greatly reducing the synthesis cost; and high-purity SZZ-39 zeolite molecular sieves can be obtained, and the reaction conditions are safe; the production process is significantly simplified and the production cost is reduced, enabling large-scale production.

[0108] This application provides an SZZ-39 zeolite molecular sieve prepared by the above preparation method. In the SZZ-39 zeolite molecule, the Si / Al molar ratio = 7 to 10.

[0109] As a preference of the above embodiment, the Si / Al molar ratio in the SZZ-13 zeolite molecule is preferably 7 to 9.

[0110] The SZZ-39 zeolite molecular sieve provided by this application has a high silicon content, high crystallinity, and uniform particle size, and the particle size is 2 to 5 μm.

[0111] After obtaining the SZZ-39 type zeolite molecular sieve in this application, under the condition of removing the template agent, the SZZ-39 type zeolite molecular sieve is mixed with a cation solution, and after an ion exchange reaction, it is calcined to obtain a modified M-SAPO-RHO type zeolite molecular sieve; the cations in the cation solution include NH4 + , Li + , Na + , K + or Cs + ; the concentration of the cation solution is 0.5 to 1.0 mol / L.

[0112] As a preference of the above embodiment, the cations in the above cation solution are derived from one of soluble lithium salts, sodium salts, potassium salts, and cesium salts. The soluble salts preferably include chlorides and sodium nitrate.

[0113] As a preference of the above embodiment, the preferred mixing method of the SSZ-39 type zeolite molecular sieve and the cation solution is stirring and mixing.

[0114] As a preference of the above embodiment, the ratio of the mass of the SSZ-39 type zeolite molecular sieve to the volume of the cation solution (i.e., the solid-liquid ratio S / L) is preferably 1 g:(20 to 200) mL, more preferably 1 g:(50 to 150) mL. The temperature of the ion exchange reaction is 20 to 100 °C, more preferably 20 to 80 °C. The time is preferably 2 to 20 h, more preferably 6 to 16 h.

[0115] As a preference of the above embodiment, during the ion exchange reaction, NH4 + , Li + , Na + , K + or Cs +Ion exchange of SSZ-39 zeolite molecular sieve changes the cation composition and content of M-SSZ-39 zeolite molecular sieve, thereby greatly improving the selective adsorption capacity of modified M-SSZ-39 for C2H6, C3H8, C3H6, C2H4 and CO2.

[0116] This application also provides the application of the SZZ-39 and M-SSZ-39 zeolite molecular sieves described in the above technical solutions in the field of selective adsorption and separation of light alkanes, light olefins and carbon dioxide gas.

[0117] As a preference of the above embodiment, the application includes the selective adsorption of C2H6, C3H8, C3H6, C2H4 and CO2 in mixed gas systems such as C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4, CO2 / N2.

[0118] As a preference of the above embodiment, before the SZZ-39 zeolite molecular sieve selectively adsorbs light alkynes / olefins / alkanes and carbon dioxide gas, it is preferably to perform a dealuminizing agent treatment on the SZZ-39 zeolite molecular sieve first. The temperature of the dealuminizing agent treatment is preferably 600 °C; the temperature of the vacuum activation treatment is preferably 350 °C; the time of the vacuum activation treatment is preferably 6-10 h. This application has no special limitation on the vacuum degree of the vacuum activation treatment, and the well-known vacuum degree in the art can be adopted.

[0119] The following Examples 1-5 are specific preparation methods of SZZ-13 zeolite molecular sieve.

[0120] Example 1

[0121] Preparation of FAU zeolite precursor solution:

[0122] Under closed, room temperature and stirring conditions, 6.53 g of sodium hydroxide, 1.23 g of sodium aluminate and 19.8 g of deionized water are mixed evenly in a reaction vessel, and then 6 g of silica white is added to obtain the initial gel of the FAU zeolite precursor solution; wherein, the molar ratio of SiO2:Al2O3:NaOH:H2O = 10.0:0.7:18:160. Under room temperature conditions, after stirring for 24 h, it is left to age at 50 °C for 24 h and then used for the subsequent SSZ-39 synthesis experiment.

[0123] Synthesis of SSZ-39 zeolite molecular sieve:

[0124] Under airtight, room temperature and stirring conditions, 0.05 g of sodium aluminate, 2.5 g of the organic template N,N-dimethyl-3,5-dimethylpiperidinium hydroxide (25 wt%) and deionized water were added to a reaction vessel and mixed evenly. Subsequently, 2 g of the FAU zeolite precursor solution and 2.5 g of silica sol (SiO₂ 40 wt%) were added and mixed evenly. Under the condition of 80 °C at room temperature, the excess water was evaporated to obtain the initial reaction gel; wherein, the molar ratio of SiO₂:Al₂O₃:NaOH:OSDA:H₂O = 1.15:0.0327:0.45:0.21:12.

[0125] The gel was statically crystallized at 170 °C for 24 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 6 h to obtain the SSZ-39 zeolite molecular sieve (abbreviated as S-1).

[0126] The X-ray powder diffraction pattern of the SSZ-39 zeolite molecular sieve prepared in this example is as Figure 1 shown by the curve S-1 in. By comparing with the standard diffraction pattern published by the International Zeolite Association, it can be known that S-1 is the SSZ-39 zeolite molecular sieve with the AEI structure. The Si / (Si+Al) molar ratio of S-1 measured by XRF = 8.1.

[0127] The scanning electron microscope image of the SSZ-39 zeolite molecular sieve prepared in this example is as Figure 2 shown by S-1 in. It can be Figure 2 seen that the particle size of S-1 is about 3 μm.

[0128] Example 2

[0129] Preparation of the FAU zeolite precursor solution:

[0130] Under airtight, room temperature and stirring conditions, 5.33 g of sodium hydroxide, 1.23 g of sodium metaaluminate and 19.8 g of deionized water were added to a reaction vessel and mixed evenly. Subsequently, 6 g of white carbon black was added to obtain the initial gel of the FAU zeolite precursor solution; wherein, the molar ratio of SiO₂:Al₂O₃:NaOH:H₂O = 10.0:0.7:15:160. Under room temperature conditions, after stirring for 24 h, it was left to age at 60 °C for 24 h and then used for the subsequent SSZ-39 synthesis experiment.

[0131] Synthesis of the SSZ-39 zeolite molecular sieve:

[0132] Under airtight conditions, at room temperature and with stirring, 0.025 g of sodium aluminate, 2.0 g of the organic template N,N-dimethyl-3,5-dimethylpiperidinium hydroxide (25 wt%) and deionized water were added to a reaction vessel and mixed evenly. Subsequently, 2 g of the FAU zeolite precursor solution and 2.1 g of silica sol (SiO₂ 40 wt%) were added and mixed evenly to obtain the initial reaction gel; wherein, the molar ratio of SiO₂:Al₂O₃:NaOH:OSDA:H₂O = 1.0:0.025:0.45:0.2:10.

[0133] The gel was statically crystallized at 180 °C for 6 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 12 h to obtain the SSZ-39 zeolite molecular sieve. The Si / (Si + Al) molar ratio of S-2 measured by XRF was 8.3.

[0134] Example 3

[0135] Preparation of the FAU zeolite precursor solution:

[0136] Under airtight conditions, at room temperature and with stirring, 5.93 g of sodium hydroxide, 1.23 g of sodium metaaluminate and 19.8 g of deionized water were added to a reaction vessel and mixed evenly. Subsequently, 6 g of white carbon black was added to obtain the initial gel of the FAU zeolite precursor solution; wherein, the molar ratio of SiO₂:Al₂O₃:NaOH:H₂O = 10.0:0.7:16.5:160. Under room temperature conditions, after stirring for 24 h, it was left to age statically at 50 °C for 24 h and then used for the subsequent SSZ-39 synthesis experiment.

[0137] Synthesis of the SSZ-39 zeolite molecular sieve:

[0138] Under airtight conditions, at room temperature and with stirring, 2.38 g of the organic template N,N-dimethyl-3,5-dimethylpiperidinium hydroxide (25 wt%) and deionized water were added to a reaction vessel and mixed evenly. Subsequently, 2 g of the FAU zeolite precursor solution and 2.1 g of silica sol (SiO₂ 40 wt%) were added and mixed evenly to obtain the initial reaction gel; wherein, the molar ratio of SiO₂:Al₂O₃:NaOH:OSDA:H₂O = 1.0:0.018:0.45:0.2:10.

[0139] The gel was statically crystallized at 130 °C for 120 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 12 h to obtain the SSZ-39 zeolite molecular sieve. The Si / (Si + Al) molar ratio of S-3 measured by XRF was 7.9.

[0140] Example 4

[0141] Preparation of FAU zeolite precursor solution:

[0142] Under closed, room temperature and stirring conditions, 5.93 g of sodium hydroxide, 1.23 g of sodium aluminate and 19.8 g of deionized water were added to a reaction vessel and mixed evenly. Subsequently, 15 g of silica sol (SiO₂ 40 wt%) was added to obtain the initial gel of the FAU zeolite precursor solution. Among them, the molar ratio of SiO₂:Al₂O₃:NaOH:H₂O = 10.0:0.7:16.5:160. Under room temperature conditions, after stirring for 24 h, it was left to age statically at 50 °C for 24 h and then used for the subsequent SSZ-39 synthesis experiment.

[0143] Synthesis of SSZ-39 zeolite molecular sieve:

[0144] Under closed, room temperature and stirring conditions, 0.019 g of aluminum hydroxide, 2.38 g of organic template N,N-dimethyl-3,5-dimethylpiperidinium hydroxide (25 wt%) and deionized water were added to a reaction vessel and mixed evenly. Subsequently, 2 g of the FAU zeolite precursor solution and 2.1 g of silica sol (SiO₂ 40 wt%) were added and mixed evenly to obtain the initial reaction gel. Among them, the molar ratio of SiO₂:Al₂O₃:NaOH:OSDA:H₂O = 1.0:0.025:0.45:0.2:10.

[0145] The gel was statically crystallized at 160 °C for 48 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 12 h to obtain the SSZ-39 zeolite molecular sieve. The Si / (Si + Al) molar ratio of S-4 measured by XRF = 8.0.

[0146] Example 5

[0147] Preparation of FAU zeolite precursor solution:

[0148] Under closed, room temperature and stirring conditions, 6.53 g of sodium hydroxide, 1.13 g of aluminum hydroxide and 19.8 g of deionized water were added to a reaction vessel and mixed evenly. Subsequently, 6 g of white carbon black was added to obtain the initial gel of the FAU zeolite precursor solution. Among them, the molar ratio of SiO₂:Al₂O₃:NaOH:H₂O = 10.0:0.7:16.5:160. Under room temperature conditions, after stirring for 24 h, it was left to age statically at 50 °C for 24 h and then used for the subsequent SSZ-39 synthesis experiment.

[0149] Synthesis of SSZ-39 zeolite molecular sieve:

[0150] Under airtight conditions, at room temperature and with stirring, 0.038 g of aluminum hydroxide, 3 g of the organic template N,N-dimethyl-3,5-dimethylpiperidinium hydroxide (25 wt%) and deionized water were added to a reaction vessel and mixed evenly. Subsequently, 2 g of the FAU zeolite precursor solution and 0.84 g of silica white were added and mixed evenly to obtain an initial reaction gel; wherein, the molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O = 1.0:0.025:0.45:0.2:10.

[0151] The gel was statically crystallized at 150 °C for 96 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 6 h to obtain the SSZ-39 zeolite molecular sieve. The Si / (Si+Al) molar ratio of S-5 measured by XRF was 8.3.

[0152] Example 6

[0153] Preparation of the FAU zeolite precursor solution:

[0154] Under airtight conditions, at room temperature and with stirring, 6.53 g of sodium hydroxide, 1.23 g of sodium aluminate and 19.8 g of deionized water were added to a reaction vessel and mixed evenly. Subsequently, 15 g of silica sol (SiO2 40 wt%) was added to obtain the initial gel of the FAU zeolite precursor solution; wherein, the molar ratio of SiO2:Al2O3:NaOH:H2O = 10.0:0.7:18:160. Under room temperature conditions, after stirring for 24 h, it was left to age at room temperature for 24 h and then used for the subsequent SSZ-39 synthesis experiment.

[0155] Synthesis of the SSZ-39 zeolite molecular sieve:

[0156] Under airtight conditions, at room temperature and with stirring, 0.098 g of aluminum isopropoxide, 3 g of the organic template N,N-dimethyl-3,5-dimethylpiperidinium hydroxide (25 wt%) and deionized water were added to a reaction vessel and mixed evenly. Subsequently, 2 g of the FAU zeolite precursor solution and 2.5 g of silica sol (SiO2 40 wt%) were added and mixed evenly to obtain an initial reaction gel; wherein, the molar ratio of SiO2:Al2O3:NaOH:OSDA:H2O = 1.0:0.025:0.45:0.2:10.

[0157] The gel was statically crystallized at 170 °C for 12 h. After the obtained crystallization system was cooled to room temperature, it was centrifuged and washed. The obtained solid product was placed in an oven at 100 °C and dried for 6 h. The Si / (Si+Al) molar ratio of S-6 measured by XRF was 7.8.

[0158] Example 7

[0159] After subjecting the SSZ-39 zeolite molecular sieves prepared in Examples 1 to 6 to high-temperature calcination to remove the organic template agent, ion exchange was carried out to obtain M-SSZ-39 (M = NH4 + , Li + , Na + , K + , Cs + ) zeolite molecular sieves. According to the ratio of the mass of the SSZ-39 type zeolite molecular sieve to the volume of the chloride salt solution S / L = 1:100, the SSZ-39 type zeolite molecular sieves prepared in Examples 1 to 6 and 1 mol / L chloride salt solution were stirred and mixed at room temperature for 6 h, and then filtered and washed with water 3 times. The above operation was repeated to obtain M-SSZ-39 with different cation contents. The obtained solid material was washed with deionized water and dried at 100 °C for 12 h, and then placed in a muffle furnace and calcined at 550 °C for 4 h to obtain modified M-SSZ-39 (M = H + , Li + , Na + , K + or Cs + ) type zeolite molecular sieves.

[0160] Application Example

[0161] Gas selective adsorption and separation tests were carried out on the modified M-SSZ-39 zeolite molecular sieves prepared in Example 7. Before the test, all M-SSZ-39 type zeolite molecular sieves were activated at 200 - 350 °C under vacuum for 4 - 10 h. After the sample was cooled to room temperature, single-component gas isothermal adsorption and desorption tests were carried out. The test temperature was 298 K and the test pressure was 0 - 1 bar. Taking Na-SSZ-39 as an example, the results are as Figure 3 shown.

[0162] It can be Figure 3 seen that the Na-SSZ-39 zeolite molecular sieve prepared by the present invention has excellent selective adsorption and separation performance for mixed gases such as C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4, CO2 / N2, etc.

[0163] The above are only several embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all belong to the scope of the technical solution.

Claims

1. A method for preparing zeolite SSZ-39 with an AEI framework, characterized in that, The method comprises the following steps: S1: Mix raw materials including a silicon source, an aluminum source, an organic template agent, a FAU zeolite precursor solution, and deionized water to obtain an initial gel; wherein, the organic template agent is selected from N,N-dimethyl-3,5-dimethylpiperidinium hydroxide; the FAU zeolite precursor solution is obtained by mixing and aging raw materials including an aluminum source, a silicon source, an inorganic base, and water; S2: Heat and crystallize the initial gel in step S1 under sealed conditions to obtain a crystallized product; S3: Separate, wash, and dry the crystallized product in step S2 to obtain the SSZ-39 zeolite molecular sieve.

2. The method for preparing zeolite SSZ-39 with an AEI framework according to claim 1, characterized in that, In step S1, the molar ratios of the silicon source, aluminum source, inorganic base, organic template agent, and water in the initial gel are: Al2O3 / SiO2 = 0.01 - 0.05; NaOH / SiO2 = 0.1 - 0.7; H2O / SiO2 = 5 - 30; R / SiO2 = 0.1 - 0.5; wherein, the molar amount of the silicon source is calculated as the molar amount of SiO2, the molar amount of the aluminum source is calculated as the molar amount of Al2O3, the molar amount of the inorganic base is calculated as the molar amount of sodium ions in the FAU zeolite precursor solution, the molar amount of the organic template agent is calculated as the molar amount of R, and the molar amount of water is calculated as the molar amount of H2O itself.

3. The method for preparing zeolite SSZ-39 with an AEI framework according to claim 1, characterized in that, In step S1, the molar ratios of the silicon source, aluminum source, inorganic base, and water in the FAU zeolite precursor solution are: Al2O3 / SiO2 = 0.03 - 0.1; NaOH / SiO2 = 1.2 - 2.0; H2O / SiO2 = 10 - 20; wherein, the molar amount of water is calculated as the molar amount of H2O itself, the molar amount of the silicon source is calculated as the molar amount of SiO2, the molar amount of the aluminum source is calculated as the molar amount of Al2O3, and the molar amount of the inorganic base is calculated as the molar amount of sodium ions.

4. The method for preparing zeolite SSZ-39 with an AEI framework according to claim 1, characterized in that, The preparation process of the FAU zeolite precursor solution in step S1 includes: Mix raw materials including an aluminum source, an inorganic base, and water, stir until the aluminum source is completely dissolved, add the silicon source, and continue to stir until a clear and transparent solution is obtained. Age at a temperature of 20 - 80 °C for 6 - 24 h to obtain the FAU zeolite precursor solution.

5. The method for preparing zeolite SSZ-39 with an AEI framework according to claim 1, characterized in that, The silicon source in the initial reaction gel or the FAU zeolite precursor solution is independently selected from at least one of fumed silica, silica sol, chromatography silica gel, water glass, and tetraethyl orthosilicate.

6. The method for preparing zeolite SSZ-39 with an AEI framework according to claim 1, characterized in that, The aluminum source in the initial reaction gel or the FAU zeolite precursor solution is independently selected from at least one of aluminum salts, aluminates, activated alumina, aluminum hydroxide, pseudo-boehmite, aluminum isopropoxide, and aluminum n-butoxide.

7. The method for preparing zeolite SSZ-39 with an AEI framework according to claim 1, characterized in that, In step S2, the conditions for the heat crystallization include: Crystallization temperature: 130 - 180 °C; Crystallization pressure: autogenous pressure; Crystallization time: 6 - 120 h; Preferably, the crystallization is dynamic crystallization or static crystallization.

8. A zeolite SSZ-39 with an AEI framework, characterized in that, It is prepared by the method according to any one of claims 1 - 7.

9. A zeolite SSZ-39 with an AEI framework according to claim 1, characterized in that In the molecular sieve SSZ-39, Si / Al = 7.0 - 10, and the crystal size is 1 - 5 μm.

10. Use of the zeolite SSZ-39 with an AEI framework prepared by the method according to any one of claims 1 to 7 in the selective adsorption separation of C2H6 / CH4, C3H8 / CH4, C2H4 / C3H6, C2H4 / C2H6, C3H6 / C3H8, CO2 / CH4, CO2 / N2.

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