Sheet-like fer molecular sieve with controllable thickness and preparation method and application thereof
By regulating the growth of FER molecular sieve crystals with growth regulators, the synthesis of high-silicon-to-aluminum ratio sheet-like FER molecular sieves with controllable thickness was achieved, solving the problem of high-silicon-to-aluminum ratio FER molecular sieve synthesis. This technology can be applied to acoustic enhancement materials to improve loudspeaker performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SSI NEW MATERIAL (ZHENJIANG) CO LTD
- Filing Date
- 2023-09-07
- Publication Date
- 2026-08-04
AI Technical Summary
Existing technologies make it difficult to synthesize granular FER molecular sieves with high silicon-to-aluminum ratios, which leads to catalysts being prone to coking and deactivation during long-term operation, and traditional sheet-like FER molecular sieves have limited performance in the adsorption field.
FER molecular sieve crystal growth was regulated by growth regulators. By controlling the Z/SiO2 ratio within the range of 0.1 to 1, plate-like FER molecular sieves with controllable thickness were synthesized. Combined with template agents and mineralizers, controllable synthesis of different thicknesses was achieved.
The synthesized sheet-like FER molecular sieve has a high silicon-to-aluminum ratio, good crystallinity and large specific surface area. When used as an acoustic reinforcement material in the rear cavity of a loudspeaker, it significantly improves acoustic performance.
Smart Images
Figure CN117208925B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of molecular sieve preparation, specifically to a sheet-like FER molecular sieve with controllable thickness, its preparation method, and its application. Background Technology
[0002] Molecular sieves with typical FER topologies were first synthesized by Plank in 1977 using a hydrothermal synthesis method. These sieves possess a highly interconnected cross-channel structure, where the five-membered ring basic framework unit forms a three-dimensional spatial grid with six- and ten-membered ring channels. This, in turn, creates a two-dimensional channel system with interlaced eight- and ten-membered rings parallel to the (010) and (001) crystal planes of the sieve, with channel sizes of 0.35 nm × 0.48 nm and 0.42 nm × 0.54 nm, respectively. Artificially synthesized FER molecular sieves offer advantages such as high crystallinity and adjustable silicon-to-aluminum ratios. Their unique two-dimensional channel structure provides excellent shape selectivity and catalytic performance, making them widely used in chemical reactions and separations.
[0003] Although FER molecular sieves have promising applications, most industrially produced FER molecular sieves currently have a low silica-alumina ratio. Under long-term operation, low silica-alumina ratio FER molecular sieves are prone to coking, leading to catalyst deactivation. In contrast, high silica-alumina ratio FER molecular sieves exhibit higher hydrothermal stability and unique catalytic properties, making them more suitable for use as industrial catalysts.
[0004] Traditionally synthesized FER molecular sieves are primarily plate-shaped, which is advantageous for shortening mass transfer pathways and reducing diffusion limitations. Particulate FER molecular sieves possess wider pores and exhibit excellent performance in adsorption; however, the controllable synthesis of particulate high silica-to-alumina ratio FER molecular sieves remains a challenge. Therefore, developing a method for synthesizing high silica-to-alumina ratio FER molecular sieves with controllable thickness and its acoustic enhancement materials is of great significance. Summary of the Invention
[0005] The purpose of this invention is to provide a sheet-like FER molecular sieve with controllable thickness, its preparation method, and its applications. This preparation method can produce sheet-like FER molecular sieves with adjustable thickness and high silica-to-alumina ratio, and the synthesized sheet-like FER molecular sieves have characteristics such as high crystallinity and large specific surface area. The obtained sheet-like FER molecular sieves of different thicknesses can be used as raw materials to produce acoustic reinforcement materials. Assembling these acoustic reinforcement materials in the rear cavity of a loudspeaker can significantly improve its acoustic performance.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] This invention provides a method for preparing a sheet-like FER molecular sieve with controllable thickness, the method comprising the following steps:
[0008] A raw material mixture is obtained by mixing an alkali source, a silicon source, an aluminum source, deionized water, a mineralizing agent, a template agent, and a growth regulator.
[0009] The raw material mixture is subjected to a hydrothermal crystallization reaction, and the product is washed, dried and calcined to obtain the sheet-like FER molecular sieve.
[0010] The molar ratios of the raw materials are as follows: SiO2 / Al2O3 = 60–500, preferably 100–500, such as 100, 150, 200, 250, 300, 350, 400, 450, 500, etc.; Na2O / SiO2 = 0.01–0.5, preferably 0.01–0.1, more preferably 0.01–0.03, such as 0.01, 0.025, 0.03, etc.; H2O / SiO2 = 10–50, such as… 10, 20, 24, 30, 40, 50, etc.; X / SiO2 = 0.1~5, preferably 0.1~1, for example 0.1, 0.5, 0.8, 1.0, etc.; Y / SiO2 = 1~2, preferably 1~1.5, for example 1, 1.5, etc.; Z / SiO2 = 0.1~1, preferably 0.3~0.6, for example 0.3, 0.4, 0.5, 0.6, etc.; X is used to represent mineralizer, Y is used to represent template agent, and Z is used to represent growth regulator.
[0011] The preparation method controls the thickness of the resulting sheet-like FER molecular sieve within the range of 0.2 to 5 μm by controlling the Z / SiO2 ratio to vary within the range of 0.1 to 1.
[0012] The template agent is selected from one or more of pyridine, pyrrolidine, piperidine, ethylenediamine and cyclohexylamine; the growth regulator is n-propylamine or tetramethylammonium hydroxide.
[0013] The preparation method of this invention, by adding a growth regulator, can synthesize sheet-like high silica-to-alumina ratio FER molecular sieves with an adjustable thickness within the range of 0.2–5 μm (silicon-to-alumina ratio can reach 60–500), while ensuring high crystallinity and a large specific surface area, thus meeting the needs of different application fields. The controllable thickness mentioned in this invention refers to the ability to controllably synthesize sheet-like FER molecular sieves of different thicknesses by using a certain template agent while adding a growth regulator and controlling its amount under different requirements.
[0014] According to the preparation method of the present invention, preferably, when Z / SiO2 = 0.1 to 0.3, the thickness of the obtained sheet-like FER molecular sieve is 0.2 to 0.5 μm;
[0015] When Z / SiO2 = 0.3–0.6, the thickness of the obtained plate-like FER molecular sieve is 0.5–2 μm;
[0016] When Z / SiO2 = 0.6 to 1, the thickness of the resulting plate-like FER molecular sieve is 2 to 5 μm.
[0017] According to the preparation method of the present invention, preferably, Z / SiO2 = 0.3 to 0.6, corresponding to a thickness of 0.5 to 2 μm for the obtained sheet-like FER molecular sieve.
[0018] In a preferred embodiment, the molar ratio of each raw material is 1.0SiO2:0.002Al2O3:0.025Na2O:24H2O:0.4Z:1.5Y:0.8X or 1.0SiO2:0.01Al2O3:0.025Na2O:24H2O:0.5Z:1.5Y:0.8X.
[0019] In the molar ratio of each raw material in this invention, the silicon source is converted to SiO2, the aluminum source to Al2O3, and the alkali source to Na2O.
[0020] According to the preparation method of the present invention, preferably, the silicon source is selected from one or more combinations of fumed silica, silica sol, water glass and tetraethyl silicate.
[0021] According to the preparation method of the present invention, preferably, the aluminum source is selected from one or more combinations of sodium aluminate, aluminum sulfate, aluminum nitrate and aluminum hydroxide.
[0022] According to the preparation method of the present invention, preferably, the alkali source is selected from one or a combination of two or more of sodium hydroxide, potassium hydroxide or calcium hydroxide.
[0023] According to the preparation method of the present invention, preferably, the mineralizing agent is a fluorinated mineralizing agent; the fluorinated mineralizing agent is HF, NaF or KF.
[0024] According to the preparation method of the present invention, preferably, the temperature of the hydrothermal crystallization reaction is 130-200°C and the time is 72-168h; more preferably, the temperature of the hydrothermal crystallization reaction is 150-180°C and the time is 120-168h.
[0025] According to the preparation method of the present invention, preferably, the calcination temperature is 500-700°C and the time is 12-24 hours.
[0026] According to the preparation method of the present invention, preferably, the drying temperature is 60-80℃ and the time is 12-24h.
[0027] According to the preparation method of the present invention, preferably, the preparation method uses different growth regulators and their addition ratios to obtain sheet-like FER molecular sieves of different thicknesses and dimensions. More preferably, the preparation method uses different growth regulators to adjust the average side length of the obtained FER molecular sieves to be 4-6 μm and the average thickness to be 0.2-5 μm.
[0028] In another aspect, the present invention provides a sheet-like FER molecular sieve with controllable thickness obtained by the above preparation method.
[0029] The sheet-like FER molecular sieve synthesized in this invention is a sodium-type molecular sieve. It can also be obtained as a hydrogen-type FER molecular sieve through calcination and ion exchange, or functionalized FER molecular sieves can be obtained through other cation substitutions, and then used in different industrial applications.
[0030] This invention relates to the preparation of sheet-like FER molecular sieves by adding a growth regulator to control the growth of FER molecular sieve crystals along different directions, thereby obtaining FER molecular sieves of varying thicknesses. Due to the physical adsorption interaction of the growth regulator on specific crystal surfaces, the surface free energy of the zeolite crystals is altered, thus affecting the growth rate and allowing the crystals to grow in different directions, resulting in FER molecular sieves of different sizes. This invention enables the controllable synthesis of sheet-like FER molecular sieves with an average side length of 4–6 μm and an average thickness of 0.2–5 μm.
[0031] In another aspect, the present invention provides the application of the above-obtained sheet-like FER molecular sieve with controllable thickness in the preparation of acoustic enhancement materials.
[0032] Specifically, the acoustic enhancement material is obtained by uniformly mixing the thickness-controllable sheet-like FER molecular sieve with solvent, binder, and additives to form a suspension, and then granulating and drying it into spherical particles; the thickness of the FER molecular sieve is 0.2 to 5 μm.
[0033] Preferably, the thickness of the FER molecular sieve is 0.5–2 μm. The acoustic reinforcement materials made from the sheet-like FER molecular sieves prepared in this invention exhibit different properties depending on the thickness of the sheet-like FER molecular sieves, with the thickness of 0.5–2 μm providing the best acoustic performance.
[0034] Preferably, the solvent is deionized water; the binder includes inorganic binders and / or organic binders; wherein the inorganic binder includes one or more of silica sol, alumina sol, water glass, and boehmite; the organic binder includes one or more of acrylate, epoxy, and polyurethane organic binders; and the additives are selected from one or more of ethylene glycol, propylene glycol, polypropylene glycol, and polyethylene glycol.
[0035] Preferably, based on the total weight of the suspension obtained after mixing the sheet-like FER molecular sieve, solvent, binder, and auxiliary raw materials as 100%, the amount of the sheet-like FER molecular sieve is 40% to 70%, the amount of the solvent is 20% to 50%, and the amount of the auxiliary is 0.5% to 2.5%; based on the total weight of the sheet-like FER molecular sieve as 100%, the amount of the binder is 4% to 12%.
[0036] The acoustic enhancement material of this invention uses sheet-like FER molecular sieves of varying thicknesses as raw materials, which, after molding, can produce spherical particles. The sheet-like FER molecular sieves have a two-dimensional pore structure; thinner sheets, due to their shorter pore paths, are more advantageous for the adsorption and desorption of gases, but their density is correspondingly lower. As the thickness of the sheet-like FER molecular sieve increases, the density increases, but its gas adsorption and desorption efficiency decreases. By controlling the thickness of the raw material sheet-like FER molecular sieve, an acoustic enhancement material with better acoustic performance can be obtained. The acoustic performance described in this invention is achieved by filling the rear cavity of the acoustic device with the acoustic enhancement material, which is used to absorb sound pressure and release the gas medium contained in a substantially enclosed volume, thereby virtually increasing the resonant space of the gas medium.
[0037] The beneficial effects of this invention include:
[0038] 1) The sheet-like FER molecular sieve synthesized by this invention has a silica-to-alumina ratio range of 60 to 500 and can maintain good crystallinity and purity.
[0039] 2) The sheet-like FER molecular sieve synthesized by this invention can not only achieve controllable thickness size synthesis, but also has a large specific surface area.
[0040] 3) The acoustic enhancement material prepared by this invention can be assembled into the rear cavity of a loudspeaker to significantly improve acoustic performance. Attached Figure Description
[0041] Figure 1 The image shows the XRD pattern of the sodium-type FER molecular sieve sample obtained in Comparative Example 1.
[0042] Figure 2 The image shows a SEM image of the sodium-type FER molecular sieve sample obtained in Comparative Example 1.
[0043] Figure 3 The image shows the XRD pattern of the sodium-type FER molecular sieve sample obtained in Example 1.
[0044] Figure 4 The image shows a SEM image of the sodium-type FER molecular sieve sample obtained in Example 1.
[0045] Figure 5 The nitrogen adsorption-desorption isotherm of the sodium-type FER molecular sieve sample obtained in Example 1.
[0046] Figure 6 The image shows the XRD pattern of the sodium-type FER molecular sieve sample obtained in Example 2.
[0047] Figure 7 The image shows a SEM image of the sodium-type FER molecular sieve sample obtained in Example 2.
[0048] Figure 8 The image shows the XRD pattern of the sodium-type FER molecular sieve sample obtained in Example 3.
[0049] Figure 9 The image shows a SEM image of the sodium-type FER molecular sieve sample obtained in Example 3.
[0050] Figure 10 The image shows the XRD pattern of the sodium-type FER molecular sieve sample obtained in Example 4.
[0051] Figure 11 The image shows a SEM image of the sodium-type FER molecular sieve sample obtained in Example 4.
[0052] Figure 12 This is a SEM image of the sodium-type FER molecular sieve sample obtained in Example 5. Detailed Implementation
[0053] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.
[0054] All numerical specifications in this invention (e.g., temperature, time, concentration, and weight, including ranges for each) are generally approximate values that may be changed (+) or (-) in increments of 0.1 or 1.0. All numerical specifications are to be understood as being preceded by the term "about".
[0055] Comparative Example 1
[0056] This comparative example synthesizes FER molecular sieves without adding growth regulators:
[0057] Fumed silica, sodium aluminate, sodium hydroxide, deionized water, pyridine, and sodium fluoride were mixed thoroughly in a molar ratio of 1.0SiO2:0.002Al2O3:0.025Na2O:24H2O:1.5Py:0.8NaF to obtain a gel. The gel was then transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silicon-to-aluminum ratio of 500.
[0058] Figure 1The XRD pattern of the obtained sodium-type molecular sieve sample is shown, with its crystallinity used as the 100% standard. Figure 2 The image shows a scanning electron microscope (SEM) image of the obtained sodium-type FER molecular sieve sample. Figure 2 It can be seen that the sample has a typical sheet-like morphology.
[0059] Examples of sheet-like FER molecular sieves with controllable thickness:
[0060] Example 1
[0061] In this embodiment, tetramethylammonium hydroxide was used as a growth regulator to synthesize FER molecular sieves.
[0062] Fumed silica, sodium aluminate, sodium hydroxide, deionized water, tetramethylammonium hydroxide, pyridine, and sodium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.002Al2O3:0.025Na2O:24H2O:0.5TMA:1.5Py:0.8NaF and stirred until homogeneous to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silicon-to-aluminum ratio of 500.
[0063] Figure 3 The XRD pattern of the obtained sodium-type FER molecular sieve sample shows that the product has a typical FER molecular sieve structure and the relative crystallinity of the sample is 105%.
[0064] Figure 4 The image shows a scanning electron microscope (SEM) image of the obtained sodium-type FER molecular sieve sample. It can be seen from the image that the average thickness of the sample is 2 μm and the average side length is 4 μm.
[0065] Figure 5 The figure shows the nitrogen adsorption-desorption isotherms of the obtained sodium-type FER molecular sieve sample. It can be seen from the figure that the adsorption-desorption curves are Type I curves, indicating that the synthesized crystal is a microporous crystal with a BET specific surface area of up to 363.8 m². 2 / g.
[0066] Example 2
[0067] In this embodiment, tetramethylammonium hydroxide was used as a growth regulator to synthesize FER molecular sieves.
[0068] Fumed silica, sodium aluminate, sodium hydroxide, deionized water, tetramethylammonium hydroxide, pyridine, and sodium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.01Al2O3:0.025Na2O:24H2O:0.5TMA:1.5Py:0.8NaF and stirred until homogeneous to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silicon-to-aluminum ratio of 100.
[0069] Figure 6 The XRD pattern of the obtained sodium-type FER molecular sieve sample is shown in the figure. It can be seen from the figure that the product has a typical FER molecular sieve structure, and the relative crystallinity of the sample is 102%, with a BET specific surface area of up to 358.2 m². 2 / g.
[0070] Figure 7 The image shows a scanning electron microscope (SEM) image of the obtained sodium-type FER molecular sieve sample. It can be seen from the image that the average thickness of the sample is 2 μm and the average side length is 4 μm.
[0071] Example 3
[0072] In this embodiment, n-propylamine was used as a growth regulator to synthesize FER molecular sieves.
[0073] Fumed silica, sodium aluminate, sodium hydroxide, deionized water, n-propylamine, pyridine, and sodium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.002Al2O3:0.025Na2O:24H2O:0.3n-C3H9N:1.5Py:0.8NaF and stirred until homogeneous to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silicon-to-aluminum ratio of 500.
[0074] Figure 8 The XRD pattern of the obtained sodium-type FER molecular sieve sample is shown in the figure. It can be seen from the figure that the product has a typical FER molecular sieve structure, and the relative crystallinity of the sample is 110%, with a BET specific surface area of up to 366.7 m². 2 / g.
[0075] Figure 9 The image shows a scanning electron microscope (SEM) image of the obtained sodium-type FER molecular sieve sample. As can be seen from the image, the sample has a plate-like morphology with an average thickness of 0.5 μm and an average side length of 4 μm.
[0076] Example 4
[0077] In this embodiment, n-propylamine was used as a growth regulator to synthesize FER molecular sieves.
[0078] Fumed silica, sodium aluminate, sodium hydroxide, deionized water, n-propylamine, pyridine, and sodium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.01Al2O3:0.025Na2O:24H2O:0.3n-C3H9N:1.5Py:0.8NaF and stirred until homogeneous to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silicon-to-aluminum ratio of 100.
[0079] Figure 10 The XRD pattern of the obtained sodium-type FER molecular sieve sample is shown in the figure. It can be seen from the figure that the product has a typical FER molecular sieve structure, and the relative crystallinity of the sample is 106%, with a BET specific surface area of up to 363.5 m². 2 / g.
[0080] Figure 11 The image shows a scanning electron microscope (SEM) image of the obtained sodium-type FER molecular sieve sample. As can be seen from the image, the sample has a plate-like morphology with an average thickness of 0.5 μm.
[0081] Example 5
[0082] In this embodiment, n-propylamine was used as a growth regulator to synthesize FER molecular sieves.
[0083] Fumed silica, sodium aluminate, sodium hydroxide, deionized water, n-propylamine, pyridine, and sodium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.002Al2O3:0.025Na2O:24H2O:0.8n-C3H9N:1.5Py:0.8NaF and stirred until homogeneous to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silicon-to-aluminum ratio of 500.
[0084] Figure 12 The image shows a scanning electron microscope (SEM) image of the obtained sodium-type FER molecular sieve sample. The image reveals a plate-like morphology with an average thickness of 4 μm and an average side length of 6 μm. Other characterization data are shown in Table 1.
[0085] Example 6
[0086] In this embodiment, n-propylamine was used as a growth regulator to synthesize FER molecular sieves.
[0087] Fumed silica, sodium aluminate, sodium hydroxide, deionized water, n-propylamine, pyridine, and sodium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.01Al2O3:0.025Na2O:24H2O:0.8n-C3H9N:1.5Py:0.8NaF and stirred until homogeneous to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 100. Other characterization data are shown in Table 1.
[0088] Example 7
[0089] In this embodiment, tetramethylammonium hydroxide was used as a growth regulator to synthesize FER molecular sieves.
[0090] Water glass, aluminum sulfate, potassium hydroxide, deionized water, tetramethylammonium hydroxide, pyrrolidine, and sodium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.005Al2O3:0.025Na2O:24H2O:0.2TMA:1.5Pyr:0.8NaF to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 200. Other characterization data are shown in Table 1.
[0091] Example 8
[0092] In this embodiment, n-propylamine was used as a growth regulator to synthesize FER molecular sieves.
[0093] Water glass, aluminum sulfate, potassium hydroxide, deionized water, n-propylamine, pyrrolidine, and sodium fluoride were mixed thoroughly in a molar ratio of 1.0SiO2:0.005Al2O3:0.025Na2O:24H2O:0.2n-C3H9N:1.5Pyr:0.8NaF to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 200. Other characterization data are shown in Table 1.
[0094] Example 9
[0095] In this embodiment, tetramethylammonium hydroxide was used as a growth regulator to synthesize FER molecular sieves.
[0096] Silica sol, aluminum nitrate, sodium hydroxide, deionized water, tetramethylammonium hydroxide, piperidine, and potassium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.01Al2O3:0.025Na2O:24H2O:0.4TMA:1.5PI:0.8KF to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 100. Other characterization data are shown in Table 1.
[0097] Example 10
[0098] In this embodiment, n-propylamine was used as a growth regulator to synthesize FER molecular sieves.
[0099] Silica sol, aluminum nitrate, sodium hydroxide, deionized water, n-propylamine, piperidine, and potassium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.01Al2O3:0.025Na2O:24H2O:0.4n-C3H9N:1.5PI:0.8KF to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 100. Other characterization data are shown in Table 1.
[0100] Example 11
[0101] In this embodiment, tetramethylammonium hydroxide was used as a growth regulator to synthesize FER molecular sieves.
[0102] Silica sol, aluminum nitrate, sodium hydroxide, deionized water, tetramethylammonium hydroxide, ethylenediamine, and hydrogen fluoride were mixed thoroughly in a molar ratio of 1.0SiO2:0.005Al2O3:0.025Na2O:24H2O:0.5TMA:1.5EDA:0.8HF to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 200. Other characterization data are shown in Table 1.
[0103] Example 12
[0104] In this embodiment, n-propylamine was used as a growth regulator to synthesize FER molecular sieves.
[0105] Silica sol, aluminum nitrate, sodium hydroxide, deionized water, n-propylamine, ethylenediamine, and hydrogen fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.005Al2O3:0.025Na2O:24H2O:0.5n-C3H9N:1.5EDA:0.8HF to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 200. Other characterization data are shown in Table 1.
[0106] Example 13
[0107] In this embodiment, tetramethylammonium hydroxide was used as a growth regulator to synthesize FER molecular sieves.
[0108] Tetraethyl silicate, aluminum hydroxide, sodium hydroxide, deionized water, tetramethylammonium hydroxide, cyclohexylamine, and potassium fluoride were mixed in the following molar ratio: 1.0SiO2:0.005Al2O3:0.025Na2O:24H2O:0.9TMA:1.5C6H 13 N and 0.8 KF were thoroughly mixed and stirred to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160 °C for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80 °C for 18 h, and then calcined at 600 °C for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 200. Other characterization data are shown in Table 1.
[0109] Example 14
[0110] In this embodiment, n-propylamine was used as a growth regulator to synthesize FER molecular sieves.
[0111] Tetraethyl silicate, aluminum hydroxide, sodium hydroxide, deionized water, n-propylamine, cyclohexylamine, and potassium fluoride were mixed in the following molar ratio: 1.0SiO2:0.005Al2O3:0.025Na2O:24H2O:0.9n-C3H9N:1.5C6H 13 N and 0.8 KF were thoroughly mixed and stirred to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160 °C for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80 °C for 18 h, and then calcined at 600 °C for 15 h to obtain a sodium-type FER molecular sieve with a silica-to-alumina ratio of 200. Other characterization data are shown in Table 1.
[0112] As shown in Table 1 above, the FER molecular sieve samples of Examples 5-14 of this invention can achieve high crystallinity and specific surface area under high silica-to-alumina ratio synthesis conditions, and their size and thickness are controllable. The specific surface area of the 0.2–2 μm thick FER molecular sieve samples is relatively high, attributed to the fact that FER molecular sieves have a two-dimensional pore structure, resulting in higher micropore volume with a smaller thickness. The specific surface area of the 4–5 μm thick FER molecular sieves is relatively lower, corresponding to a slight decrease in their micropore volume. The controllable thickness of the FER molecular sieves obtained in these embodiments is achieved by adjusting the ratio of growth regulators.
[0113] Table 1. Characterization data related to samples 5-14 in Examples 1
[0114]
[0115] Example 15
[0116] In this embodiment, tetramethylammonium hydroxide was used as a growth regulator to synthesize FER molecular sieves.
[0117] Fumed silica, sodium aluminate, sodium hydroxide, deionized water, tetramethylammonium hydroxide, pyridine, and sodium fluoride were thoroughly mixed in a molar ratio of 1.0SiO2:0.002Al2O3:0.025Na2O:24H2O:1.5TMA:1.5Py:0.8NaF and stirred until homogeneous to obtain a gel. The gel was transferred to a reaction vessel and subjected to hydrothermal crystallization at 160℃ for 120 h. The product of the hydrothermal crystallization reaction was washed with water, centrifuged, dried at 80℃ for 18 h, and then calcined at 600℃ for 15 h to obtain FER+MFI mixed crystal molecular sieve.
[0118] In addition, the proportions of template agent and growth regulator in the raw materials were changed to prepare the product, and the results are shown in Table 2.
[0119] Table 2 shows that adding too much growth regulator can lead to the formation of heterocrystalline phases in the synthesized sample, or even transformation into the quartz phase. Reducing the amount of template agent results in an amorphous sample.
[0120] Table 2 Characterization data of samples obtained from template agents and growth regulators at different dosage ratios.
[0121]
[0122] Performance testing of acoustic reinforcement materials:
[0123] 51.9 g of FER molecular sieve synthesized in Comparative Example 1, Example 1, Example 3, and Example 5 were thoroughly mixed with 12 g of polyurethane suspension with a solid content of 35%, 1 g of polyethylene glycol (200), and 35.1 g of water to obtain 100 g of mixed suspension. After granulation and drying, spherical particles were obtained, and then they were loaded into tooling for acoustic performance testing. The results are shown in Table 3. 61.2 g of FER molecular sieve synthesized in Comparative Example 1, Example 2, Example 4, and Example 6 were thoroughly mixed with 12 g of polyurethane suspension with a solid content of 35%, 1 g of polyethylene glycol (200), and 25.8 g of water to obtain 100 g of mixed suspension. After granulation and drying, spherical particles were obtained, and then they were loaded into tooling for acoustic performance testing. The results are shown in Table 3.
[0124] Table 3. Relevant data for samples of different acoustic enhancement materials
[0125]
[0126] As can be seen from the experimental results in Table 3, the FER molecular sieve synthesized in Comparative Example 1 had a very small thickness and low density because no growth regulator was added. When the proportion of molecular sieve added to the raw material suspension was too high during the granulation process, the pore volume of the granules after drying was small, resulting in poor adsorption and desorption performance of air molecules and poor acoustic performance.
[0127] The 0.5–2 μm thick FER molecular sieves prepared using Examples 1–6 exhibit high micropore volume and density, and the acoustic performance of the granulated acoustic reinforcement material is significantly better than that of the thinner Comparative Example 1. As the thickness of the FER molecular sieve further increases, the micropore volume decreases, resulting in a corresponding reduction in adsorption capacity and acoustic performance. Based on the above data, this invention uses FER molecular sieves with controllable thickness as raw material to prepare acoustic reinforcement materials. Assembling these acoustic reinforcement materials into the rear cavity of a loudspeaker can significantly improve its acoustic performance.
[0128] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.
Claims
1. A method for preparing a sheet-like FER molecular sieve with controllable thickness, characterized in that, The preparation method includes the following steps: A raw material mixture is obtained by mixing an alkali source, a silicon source, an aluminum source, deionized water, a mineralizing agent, a template agent, and a growth regulator. The raw material mixture is subjected to a hydrothermal crystallization reaction, and the product is washed, dried and calcined to obtain the sheet-like FER molecular sieve. The molar ratios of the raw materials are as follows: SiO2 / Al2O3 = 60~500, Na2O / SiO2 = 0.01~0.5, H2O / SiO2 = 10~50, X / SiO2 = 0.1~5, Y / SiO2 = 1~2 and Z / SiO2 = 0.1~1. X represents the mineralizer, Y represents the template agent, and Z represents the growth regulator. The silicon source is converted to SiO2, the aluminum source to Al2O3, and the alkali source to Na2O. The preparation method controls the thickness of the resulting sheet-like FER molecular sieve within the range of 0.2 to 5 μm by controlling the Z / SiO2 ratio to vary within the range of 0.1 to 1. The template agent is pyridine, pyrrolidine, piperidine, ethylenediamine, or cyclohexylamine; The growth regulator is n-propylamine or tetramethylammonium hydroxide.
2. The preparation method according to claim 1, characterized in that, When Z / SiO2 = 0.1~0.3, the thickness of the obtained plate-like FER molecular sieve is 0.2~0.5 μm; When Z / SiO2 = 0.3~0.6, the thickness of the obtained plate-like FER molecular sieve is 0.5~2 μm; When Z / SiO2 = 0.6~1, the thickness of the resulting sheet-like FER molecular sieve is 2~5 μm.
3. The preparation method according to claim 1, characterized in that, Y / SiO2=1~1.5; Z / SiO2=0.3~0.
6.
4. The preparation method according to claim 1, characterized in that, The silicon source is selected from one or more of fumed silica, silica sol, water glass, and tetraethyl orthosilicate.
5. The preparation method according to claim 1, characterized in that, The aluminum source is selected from one or more of sodium aluminate, aluminum sulfate, aluminum nitrate, and aluminum hydroxide.
6. The preparation method according to claim 1, characterized in that, The alkali source is sodium hydroxide.
7. The preparation method according to claim 1, characterized in that, The mineralizing agent is a fluorine-containing mineralizing agent; the fluorine-containing mineralizing agent is HF, NaF or KF.
8. The preparation method according to claim 1, characterized in that, The hydrothermal crystallization reaction is carried out at a temperature of 130~200℃ for a time of 72~168 h.
9. The preparation method according to claim 1, characterized in that, The roasting temperature is 500~700℃ and the time is 12~24 h.
10. The preparation method according to claim 1, characterized in that, The drying temperature is 60~80℃, and the time is 12-24 h.
11. A sheet-like FER molecular sieve with controllable thickness, obtained by the preparation method according to any one of claims 1-10.
12. The application of the thickness-controllable sheet-like FER molecular sieve of claim 11 in the preparation of acoustic enhancement materials.
13. An acoustic enhancement material, characterized in that, The acoustic enhancement material is obtained by uniformly mixing the sheet-like FER molecular sieve with controllable thickness as described in claim 11 with solvent, binder and additives to form a suspension, and then granulating and drying it into spherical particles; the thickness of the FER molecular sieve is 0.2~5 μm.
14. The acoustic enhancement material according to claim 13, characterized in that, The thickness of the FER molecular sieve is 0.5~2 μm.