Shape-controllable saPO-34 molecular sieve, preparation method and application thereof
By adjusting the amount of aluminum isopropoxide added, the environmental pollution and cost problems of morphology control in the existing technology were solved, and the morphology of SAPO-34 molecular sieves was controlled, improving the efficiency and selectivity of the catalytic reaction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DATANG (JIANGSU) ENVIRONMENTAL PROTECTION EQUIP CO LTD
- Filing Date
- 2024-04-30
- Publication Date
- 2026-05-12
Smart Images
Figure CN118515295B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of molecular sieve preparation technology, and in particular to a morphology-controllable SAPO-34 molecular sieve, its preparation method, and its application. Background Technology
[0002] Zeolite molecular sieves are important microporous crystalline materials. Their original name comes from natural aluminosilicates. Due to their unique microporous structure, high hydrothermal stability, chemical stability, and strong acidity, they can be used as adsorbents, catalysts, or catalyst supports, and are widely used in petrochemical, petroleum refining, and fine chemical industries.
[0003] Zeolite molecular sieves play a crucial role in catalysis. Their performance depends not only on their acidity and pore structure but also on their morphology, because the channels of zeolite molecular sieves serve as key pathways for molecular transport in catalytic reactions. Differences in the pore structure formed by different zeolite morphologies significantly affect the diffusion rate of molecules, especially in a series of acid-catalyzed reactions such as macromolecular cracking, toluene disproportionation, and methanol-to-olefins reactions, where the catalytic performance varies considerably.
[0004] Currently, methods for controlling zeolite morphology mainly include changing the type of mineralizer, introducing heteroatoms, altering the charge balance, changing the basicity in the synthesis system, and adding secondary template agents. However, these methods still have some drawbacks. For example, changing the type of mineralizer usually requires the addition of Cs. + F - 、Rb + The method introduces ions that are prone to causing environmental pollution, making it environmentally unfriendly. Furthermore, the zeolite synthesized by this method retains a certain amount of mineralizing agent cations, which negatively impacts the reaction. Changing the alkalinity of the synthesis system increases the difficulty of treating the synthesis waste liquid, raising production costs and hindering industrial application. Introducing secondary template agents interferes with zeolite crystallization, often resulting in the formation of amorphous substances and increasing production costs. These drawbacks clearly limit the application scope of the aforementioned control methods.
[0005] In view of this, the present invention is proposed. Summary of the Invention
[0006] The purpose of this invention is to provide a method for preparing SAPO-34 molecular sieves with controllable morphology. This method can adjust the microenvironment of SAPO-34 molecular sieve synthesis by changing the amount of aluminum isopropoxide added, thereby affecting the nucleation and crystal growth process of the molecular sieve and ultimately achieving the control of the morphology of SAPO-34 molecular sieves.
[0007] This invention provides a method for preparing SAPO-34 molecular sieves with controllable morphology, comprising the following steps:
[0008] S1. Add aluminum isopropoxide, silicon source, phosphorus source and structure directing agent to deionized water, stir evenly to obtain the initial gel;
[0009] S2. The initial gel is transferred to a hydrothermal reactor for hydrothermal crystallization treatment;
[0010] S3. The product obtained by hydrothermal crystallization is centrifuged, washed and dried sequentially to obtain SAPO-34 molecular sieve;
[0011] The morphology of SAPO-34 molecular sieve was adjusted by changing the amount of aluminum isopropoxide added.
[0012] Studies have shown that in the synthesis process of this invention, aluminum isopropoxide not only serves as an aluminum source to construct the molecular sieve framework, but the isopropanol generated from the high-temperature hydrolysis of aluminum isopropoxide can also increase the pressure of the synthesis system, promoting the nucleation and growth of zeolites. Simultaneously, isopropanol molecules can fill the micropores of the zeolite, acting as a structure-directing agent. Therefore, by changing the amount of aluminum isopropoxide added, the microenvironment of SAPO-34 molecular sieve synthesis can be adjusted, thereby affecting the nucleation and crystal growth process of the molecular sieve, ultimately achieving the control of the morphology of SAPO-34 molecular sieves.
[0013] As a preferred embodiment of this technical solution, in step S1, when preparing the initial gel, aluminum isopropoxide is first added to a mixture of structure directing agent and deionized water, and magnetically stirred for 3-4 hours; after complete dissolution, a silicon source is added and stirred for 2-3 hours; subsequently, a phosphorus source is slowly added and stirred for another 0.5-1 hour to obtain the initial gel.
[0014] The sequential addition of aluminum, silicon, and phosphorus sources in this invention can effectively regulate the spatial distribution of Si active sites in SAPO-34, significantly reducing the silicon enrichment on the SAPO-34 surface. Therefore, it can reduce the generation of side reactions on the molecular sieve surface in acid-catalyzed reactions, which is beneficial to improving the selectivity of the target product.
[0015] In a preferred embodiment of this technical solution, in step S1, the amounts of aluminum source, silicon source, and phosphorus source added are converted to Al2O3, SiO2, and P2O5, respectively. Therefore, in the initial gel of this invention, the molar ratio of Al2O3, SiO2, P2O5, structure directing agent, and water is (0.1-7.3):(0.1-0.9):(0.4-4.3):(0.3-15.2):(30-480). In practical applications, SAPO-34 molecular sieves with specific morphologies can be prepared by adjusting the amount of aluminum source aluminum isopropoxide added.
[0016] For example, when the molar ratio of Al2O3, SiO2, P2O5, structure directing agent and water is (0.1-1.4):(0.1-0.9):(0.4-4.3):(0.3-15.2):(30-480), spherical aggregates formed by the stacking of nanocrystals can be prepared. This structure can be used as a catalyst support for the ammonia selective catalytic reduction reaction (NH3-SCR).
[0017] When the molar ratio of Al2O3, SiO2, P2O5, structure directing agent and water is (1.4-3.2):(0.1-0.9):(0.4-4.3):(0.3-15.2):(30-480), spherical aggregates formed by the stacking of nano cubic crystals can be prepared. This structure can be applied to the CH4 / N2 separation reaction.
[0018] When the molar ratio of Al2O3, SiO2, P2O5, structure directing agent and water is (3.2-5.4):(0.1-0.9):(0.4-4.3):(0.3-15.2):(30-480), flower-like aggregates formed by the stacking of nanocrystals can be prepared. This structure can be applied to the reaction of methanol to produce low-carbon olefins (propylene and ethylene).
[0019] When the molar ratio of Al2O3, SiO2, P2O5, structure directing agent and water is (5.4-7.3):(0.1-0.9):(0.4-4.3):(0.3-15.2):(30-480), micron-sized cubic single crystals can be prepared. This structure can be used as a highly efficient catalyst in dehumidification applications.
[0020] As a preferred embodiment of this technical solution, the silicon source used in this invention includes any one or more of tetraethyl orthosilicate, silica sol, silica fume, and fumed silica; the phosphorus source includes any one or more of phosphoric acid, ammonium dihydrogen phosphate, and ammonium monohydrogen phosphate; and the structure directing agent includes any one or more of tetraethylammonium hydroxide, morpholine, diethylamine, and triethylamine.
[0021] As a preferred embodiment of this technical solution, in step S2, when the initial gel is subjected to hydrothermal crystallization treatment using a traditional hydrothermal synthesis system, the temperature can be controlled at 160-220℃ and the time at 24-72h. At this temperature, aluminum isopropoxide is conducive to constructing a molecular sieve framework structure. At the same time, the isopropanol generated by the complete hydrolysis of aluminum isopropoxide can not only fill the micropores of zeolite, but also promote the nucleation and growth of zeolite by increasing the pressure of the synthesis system.
[0022] As a preferred embodiment of this technical solution, in step S3, the present invention does not strictly limit the drying conditions, but specifically the temperature can be controlled at 80-120℃ and the time at 24-48h.
[0023] Secondly, the present invention also provides SAPO-34 molecular sieves with controllable morphology prepared according to the above preparation method, such as spherical aggregates formed by nanocrystal stacking, spherical aggregates formed by nanocubic crystal stacking, micron-sized cubic single crystals, and flower-like aggregates formed by nanocrystal stacking, which should also fall within the protection scope of the present invention.
[0024] Thirdly, the SAPO-34 molecular sieve prepared by this invention can be applied to a series of acid-catalyzed reactions such as ammonia selective catalytic reduction, dehumidification, CH4 / N2 separation reaction, or methanol to olefins.
[0025] The method for preparing SAPO-34 molecular sieves with controllable morphology of the present invention has at least the following beneficial effects:
[0026] This invention discloses a method for preparing morphology-controllable SAPO-34 molecular sieves. Employing a traditional hydrothermal synthesis system, the morphology of SAPO-34 molecular sieves can be controlled by varying the amount of aluminum isopropoxide added, without the addition of mineralizing agents or secondary template agents. This is because, during the synthesis process, aluminum isopropoxide not only serves as an aluminum source to construct the molecular sieve framework, but the isopropanol generated from the high-temperature hydrolysis of aluminum isopropoxide can increase the pressure of the synthesis system, promoting zeolite nucleation and growth. Simultaneously, isopropanol molecules can fill the micropores of the zeolite, acting as a structure-directing agent. Therefore, by changing the amount of aluminum isopropoxide added, the microenvironment of SAPO-34 molecular sieve synthesis can be adjusted, thereby affecting the nucleation and crystal growth process of the molecular sieve, ultimately achieving control over the morphology of the SAPO-34 molecular sieve. Attached Figure Description
[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0028] Figure 1 The XRD patterns of SAPO-34 molecular sieves prepared in Examples 1, 2, 3 and 4 are shown.
[0029] Figure 2 SEM image of SAPO-34 prepared in Example 1;
[0030] Figure 3 SEM image of SAPO-34 prepared in Example 2;
[0031] Figure 4SEM image of SAPO-34 prepared in Example 3;
[0032] Figure 5 SEM image of SAPO-34 prepared in Example 4;
[0033] Figure 6 The XRD patterns of SAPO-34 molecular sieves prepared in Examples 5, 6, 7 and 8 are shown.
[0034] Figure 7 SEM image of SAPO-34 prepared in Example 5;
[0035] Figure 8 SEM image of SAPO-34 prepared in Example 6;
[0036] Figure 9 SEM image of SAPO-34 prepared in Example 7;
[0037] Figure 10 SEM image of SAPO-34 prepared in Example 8;
[0038] Figure 11 The XRD patterns of SAPO-34 molecular sieves prepared in Examples 9, 10, 11 and 12 are shown.
[0039] Figure 12 SEM image of SAPO-34 prepared in Example 9;
[0040] Figure 13 SEM image of SAPO-34 prepared in Example 10;
[0041] Figure 14 SEM image of SAPO-34 prepared in Example 11;
[0042] Figure 15 SEM image of SAPO-34 prepared in Example 12;
[0043] Figure 16 The XRD patterns of the four SAPO-34 molecular sieves prepared in Comparative Example 1 are shown below.
[0044] Figure 17 SEM images of the four SAPO-34 molecular sieves prepared in Comparative Example 1;
[0045] Figure 18 The XRD patterns of the four SAPO-34 molecular sieves prepared in Comparative Example 2 are shown below.
[0046] Figure 19SEM images of the four SAPO-34 molecular sieves prepared in Comparative Example 2;
[0047] Figure 20 The XRD patterns of the four SAPO-34 molecular sieves prepared in Comparative Example 3 are shown below.
[0048] Figure 21 SEM images of the four SAPO-34 molecular sieves prepared in Comparative Example 3. Detailed Implementation
[0049] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0050] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0051] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0052] Example 1
[0053] S1. At room temperature, 4.24 g of aluminum isopropoxide was added to a mixture of 19.5 mL of tetraethylammonium hydroxide (TEAOH, 25 wt.%) and 10 mL of distilled water, and the mixture was magnetically stirred for 3.5 h. After complete dissolution, 1.2 mL of tetraethyl orthosilicate (TEOS) was added, and the mixture was stirred for 2.5 h. Subsequently, 4.0 mL of phosphoric acid (H3PO4, 85 wt.%) solution was slowly added, and the mixture was stirred for another 1 h to obtain the initial gel.
[0054] S2. The obtained initial gel was placed in a stainless steel reactor with a polytetrafluoroethylene liner (100 mL) and subjected to hydrothermal crystallization treatment at 180°C for 72 h.
[0055] S3. Wash the hydrothermally crystallized sample until neutral, and dry it overnight to obtain SAPO-34 molecular sieve.
[0056] like Figure 1As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0057] like Figure 2 As shown, the morphology of SAPO-34 obtained in this embodiment is a spherical aggregate formed by the stacking of nanocrystals.
[0058] Example 2
[0059] The amount of aluminum isopropoxide added was changed to 6.03g;
[0060] Other conditions and parameters are the same as in Example 1.
[0061] like Figure 1 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0062] like Figure 3 As shown, the morphology of SAPO-34 obtained in this embodiment is a spherical aggregate formed by the stacking of nanocubic crystals.
[0063] Example 3
[0064] The amount of aluminum isopropoxide added was changed to 9.23g;
[0065] Other conditions and parameters are the same as in Example 1.
[0066] like Figure 1 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0067] like Figure 4 As shown, the SAPO-34 obtained in this embodiment has the morphology of a spherical aggregate formed by the stacking of cubic crystals.
[0068] Example 4
[0069] The amount of aluminum isopropoxide added was changed to 15.24g;
[0070] Other conditions and parameters are the same as in Example 1.
[0071] like Figure 1 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0072] like Figure 5 As shown, the SAPO-34 obtained in this embodiment has a micron-sized cubic crystal morphology.
[0073] Example 5
[0074] S1. At room temperature, 3.57 g of aluminum isopropoxide was added to a mixture of 10 mL of diethylamine and 10 mL of distilled water and stirred magnetically for 3.5 h. After complete dissolution, 0.65 g of silica sol was added and stirred for 2.5 h. Subsequently, 4.0 mL of phosphoric acid (H3PO4, 85 wt.%) solution was slowly added and stirring was continued for 1 h to obtain the initial gel.
[0075] S2. The initial gel was placed in a stainless steel reactor with a polytetrafluoroethylene liner (100 mL) and hydrothermally crystallized at 220°C for 24 h.
[0076] S3. Wash the hydrothermally crystallized sample until neutral, and dry it overnight to obtain SAPO-34 molecular sieve.
[0077] like Figure 6 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0078] like Figure 7 As shown, the morphology of SAPO-34 obtained in this embodiment is a flower-like aggregate formed by the stacking of nanocrystals.
[0079] Example 6
[0080] The amount of aluminum isopropoxide added was changed to 5.12g;
[0081] Other conditions and parameters are the same as in Example 5.
[0082] like Figure 6 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0083] like Figure 8 As shown, the morphology of SAPO-34 obtained in this embodiment is a spherical aggregate formed by the stacking of nanocrystals.
[0084] Example 7
[0085] The amount of aluminum isopropoxide added was changed to 8.56g;
[0086] Other conditions and parameters are the same as in Example 5.
[0087] like Figure 6 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0088] like Figure 9 As shown, the morphology of SAPO-34 obtained in this embodiment is a spherical aggregate formed by the stacking of nanocubes.
[0089] Example 8
[0090] The amount of aluminum isopropoxide added was changed to 12.78g;
[0091] Other conditions and parameters are the same as in Example 5.
[0092] like Figure 6 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0093] like Figure 10 As shown, the SAPO-34 obtained in this embodiment has a micron-sized cubic crystal morphology.
[0094] Example 9
[0095] S1. At room temperature, 2.34 g of aluminum isopropoxide was added to a mixture of 7.5 mL of triethylamine and 10 mL of distilled water and stirred magnetically for 5 h. After complete dissolution, 0.72 g of fumed SiO2 was added and stirred for 4.5 h. Subsequently, 4.21 g of ammonium hydrogen phosphate was slowly added and stirred for another 1 h to obtain the initial gel.
[0096] S2. The obtained initial gel was placed in a stainless steel reactor with a polytetrafluoroethylene liner (100 mL) and hydrothermally crystallized at 190°C for 48 h.
[0097] S3. Wash the hydrothermally crystallized sample until neutral, and dry it overnight to obtain SAPO-34 molecular sieve.
[0098] like Figure 11 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0099] like Figure 12 As shown, the morphology of SAPO-34 obtained in this embodiment is a spherical aggregate formed by the stacking of nanocrystals.
[0100] Example 10
[0101] The amount of aluminum isopropoxide added was changed to 4.65g;
[0102] Other conditions and parameters are the same as in Example 9.
[0103] like Figure 11 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0104] like Figure 13 As shown, the morphology of SAPO-34 obtained in this embodiment is a spherical stack formed by the stacking of nanocubes.
[0105] Example 11
[0106] The amount of aluminum isopropoxide added was changed to 6.12g;
[0107] Other conditions and parameters are the same as in Example 9.
[0108] like Figure 11 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0109] like Figure 14 As shown, the SAPO-34 obtained in this embodiment has a morphology of a spherical stack formed by the stacking of cubic blocks.
[0110] Example 12
[0111] The amount of aluminum isopropoxide added was changed to 9.12g;
[0112] Other conditions and parameters are the same as in Example 9.
[0113] like Figure 11 As shown, the obtained sample is SAPO-34 molecular sieve, with no other impurity phases formed.
[0114] like Figure 15 As shown, the SAPO-34 obtained in this embodiment has a micron-sized cubic single crystal morphology.
[0115] Compare with Example 1
[0116] SAPO-34 molecular sieves were prepared by replacing aluminum isopropoxide with alumina in Example 1, and setting the amount of alumina added to 4.24 g, 6.03 g, 9.23 g and 15.24 g respectively.
[0117] The other steps and parameters are basically the same as in Example 1.
[0118] like Figure 16 As shown, by changing the amount of alumina added, all the samples obtained were SAPO-34 molecular sieves, and no other impurity phases were generated.
[0119] like Figure 17 As shown, by changing the amount of alumina added, the morphology of the obtained SAPO-34 was always a cubic block of ~2μm.
[0120] Compare with Example 2
[0121] SAPO-34 molecular sieves were prepared by replacing aluminum isopropoxide with aluminum hydroxide in Example 1, and setting the amount of aluminum hydroxide added to 4.24 g, 6.03 g, 9.23 g and 15.24 g respectively.
[0122] The other steps and parameters are basically the same as in Example 1.
[0123] like Figure 18 As shown, by changing the amount of aluminum hydroxide added, all the samples obtained were SAPO-34 molecular sieves, and no other impurity phases were generated.
[0124] like Figure 19As shown, by changing the amount of aluminum hydroxide added, the morphology of the obtained SAPO-34 was always 2-5 μm cubic blocks with the formation of amorphous substances.
[0125] Compare with Example 3
[0126] SAPO-34 molecular sieves were prepared by replacing aluminum isopropoxide in Example 1 with aluminum sec-butoxide, and setting the amount of aluminum sec-butoxide added to 4.24 g, 6.03 g, 9.23 g and 15.24 g respectively.
[0127] The other steps and parameters are basically the same as in Example 1.
[0128] like Figure 20 As shown, by changing the amount of aluminum sec-butoxide added, all the samples obtained were SAPO-34 molecular sieves, and no other impurity phases were generated.
[0129] like Figure 21 As shown, by varying the amount of aluminum sec-butoxide added, the resulting SAPO-34 had a morphology of 1-10 μm cubic blocks.
[0130] In summary, the morphology of the SAPO-34 molecular sieves obtained in Examples 1-12 shows that the morphology of the SAPO-34 molecular sieves can be controlled by changing the amount of aluminum isopropoxide added. From the XRD patterns and SEM images of the SAPO-34 molecular sieves obtained in Comparative Examples 1-3, it can be seen that when the aluminum source is changed to alumina and aluminum hydroxide, the isopropanol molecules, which affect zeolite nucleation and act as structure directing agents, cannot be hydrolyzed at high temperatures, thus failing to regulate the microenvironment for SAPO-34 molecular sieve synthesis and therefore failing to control the morphology of the SAPO-34 molecular sieves. When the aluminum source is changed to aluminum sec-butoxide, although aluminum sec-butoxide can be hydrolyzed at high temperatures to obtain sec-butanol, the sec-butanol is not easily miscible with water, and the pressure generated in the reaction system is relatively low, preventing the regulation of the microenvironment for SAPO-34 molecular sieve synthesis and thus failing to control the morphology of the SAPO-34 molecular sieves.
[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing SAPO-34 molecular sieves with controllable morphology, characterized in that, Includes the following steps: S1. Add aluminum isopropoxide, silicon source, phosphorus source and structure directing agent to deionized water, stir evenly to obtain the initial gel; S2. The initial gel is transferred to a hydrothermal reactor for hydrothermal crystallization treatment; S3. The product obtained by hydrothermal crystallization is centrifuged, washed and dried sequentially to obtain SAPO-34 molecular sieve; Among them, the microenvironment for the synthesis of SAPO-34 molecular sieves can be adjusted by changing the amount of aluminum isopropoxide added, thereby controlling the morphology of SAPO-34 molecular sieves. The preparation method is selected from any one of the following groups: Group 1: The structure-directing agent is tetraethylammonium hydroxide, the silicon source is tetraethyl orthosilicate, the phosphorus source is phosphoric acid, the amount of deionized water used is 10 mL, the amount of tetraethylammonium hydroxide used is 19.5 mL, the amount of tetraethyl orthosilicate used is 1.2 mL, the amount of phosphoric acid used is 4.0 mL, and the concentration of phosphoric acid is 85 wt.%. When the amount of aluminum isopropoxide added is 4.24 g, spherical aggregates formed by the stacking of nanocrystals are prepared. When the amount of aluminum isopropoxide added is 6.03 g, spherical aggregates formed by the stacking of nano cubic crystals are prepared. When the amount of aluminum isopropoxide added is 9.23 g, spherical aggregates formed by the stacking of cubic crystals are prepared. When aluminum isopropoxide was added in an amount of 15.24 g, micron-sized cubic crystals were prepared. Group 2: The structure-directing agent is diethylamine, the silicon source is silica sol, the phosphorus source is phosphoric acid, the amount of deionized water used is 10 mL, the amount of diethylamine used is 10 mL, the amount of silica sol used is 0.65 g, the amount of phosphoric acid used is 4.0 mL, and the concentration of phosphoric acid is 85 wt.%. When the amount of aluminum isopropoxide added is 3.57 g, a flower-like aggregate formed by the stacking of nanocrystals is prepared. When the amount of aluminum isopropoxide added is 5.12 g, spherical aggregates formed by the stacking of nanocrystals are prepared. When the amount of aluminum isopropoxide added is 8.56 g, spherical aggregates formed by the stacking of nanocubes are prepared. When aluminum isopropoxide was added in an amount of 12.78 g, micron-sized cubic crystals were prepared. Group 3: The structure directing agent is triethylamine, the silicon source is fumed silica, the phosphorus source is ammonium hydrogen phosphate, the amount of deionized water is 10 mL, the amount of triethylamine is 7.5 mL, the amount of fumed silica is 0.72 g, and the amount of ammonium hydrogen phosphate is 4.21 g. When the amount of aluminum isopropoxide added is 2.34 g, spherical aggregates formed by the stacking of nanocrystals are prepared. When the amount of aluminum isopropoxide added is 4.65 g, a spherical stack formed by the stacking of nanocubes is prepared. When the amount of aluminum isopropoxide added is 6.12 g, a spherical stack formed by the stacking of cubic blocks is prepared. When the amount of aluminum isopropoxide added is 9.12 g, micron-sized cubic single crystals are prepared.
2. The preparation method according to claim 1, characterized in that, In step S1, when preparing the initial gel, aluminum isopropoxide is first added to a mixture of structure directing agent and deionized water and magnetically stirred for 3-4 hours; after it is completely dissolved, a silicon source is added and stirred for 2-3 hours; then, a phosphorus source is slowly added and stirred for another 0.5-1 hour to obtain the initial gel.
3. The preparation method according to claim 1, characterized in that, In step S2, the hydrothermal crystallization treatment is carried out at a temperature of 160-220℃ for a time of 24-72 hours.
4. The preparation method according to claim 1, characterized in that, In step S3, during the drying process, the temperature is controlled at 80-120℃ and the time is 24-48h.
5. A SAPO-34 molecular sieve with controllable morphology, characterized in that, It is prepared according to any one of claims 1-4.
6. The application of the SAPO-34 molecular sieve according to claim 5 or the SAPO-34 molecular sieve prepared by any one of the preparation methods according to claims 1-4 in ammonia selective catalytic reduction reaction, dehumidification, CH4 / N2 separation reaction or methanol to olefins.