A method for preparing and applying ZJM-11 molecular sieve containing phosphorus and aluminum.

Abstract

This invention relates to molecular sieve preparation technology, aiming to provide a method for preparing and applying ZJM-11 molecular sieves containing phosphorus aluminum. The method includes: preparing calcined ZJM-8 molecular sieves according to the method described in patent document CN116199240B; mixing the molecular sieves with water, stirring evenly at room temperature, and then carrying out a crystallization reaction; washing and drying the reaction product to obtain ZJM-11 molecular sieves. This invention solves the technical problem of structural collapse and pore failure in traditional six-membered ring phosphorus aluminum molecular sieves due to the removal of guest species; the molecular sieve product has open and stable intrinsic pores, maintaining structural integrity without the need for structure-directing agents, laying the foundation for its application in the field of gas adsorption. The synthesis method of this invention uses molecular sieves with specific structures as the starting point for transformation, with simple processes and good reproducibility, providing a topological transformation pathway for synthesizing novel molecular sieves.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve preparation, specifically to a method for preparing and applying a phosphorus-aluminum-containing ZJM-11 molecular sieve. Background Technology

[0002] In the field of porous materials research, aluminum phosphate molecular sieves have attracted much attention due to their tunable framework structure. For a long time, synthetic exploration in this field has mainly focused on molecular sieves with pore sizes of eight-membered rings and above, aiming to achieve the catalysis and separation of macromolecules. In stark contrast, small-pore molecular sieves composed of six-membered rings are often considered to lack effective pore space and application value, and have rarely been systematically studied and developed. However, this perception overlooks the unique potential of the six-membered ring structure in specific adsorption separations. Its pore size allows smaller gas molecules (such as hydrogen and water molecules) to preferentially diffuse in, while effectively excluding most gas molecules with larger kinetic diameters (such as nitrogen, oxygen, and methane), giving it theoretical superiority in the field of gas adsorption separation.

[0003] Even though researchers have a clear theoretical understanding of the properties of six-membered ring structures, a fundamental challenge remains when applying them to practical applications. Under traditional synthetic techniques, the limited pore space of six-membered ring molecular sieves is easily and permanently occupied by structure-directing agents or inorganic ions used to balance charges. Since the stability of the six-membered ring framework is highly dependent on these guest species, removing them often leads to structural collapse, causing the intrinsic pores to fail and ultimately resulting in the loss of separation function. Therefore, developing six-membered ring aluminum phosphate molecular sieves that overcome these limitations and possess stable pores has become a pressing technical challenge in this field.

[0004] For the reasons mentioned above, this invention aims to provide a novel preparation technology for six-membered ring molecular sieves and to use it for the adsorption of hydrogen. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing and applying ZJM-11 molecular sieve containing phosphorus and aluminum.

[0006] To solve the technical problem, the solution of the present invention is:

[0007] This invention provides a method for preparing ZJM-11 molecular sieve containing phosphorus and aluminum, comprising the following steps:

[0008] (1) The ZJM-8 molecular sieve after calcination was prepared according to the method described in patent document CN116199240B (ZL 2023 1 0000216.7, a method for preparing and applying a phosphorus-aluminum-containing ZJM-8 molecular sieve);

[0009] (2) Mix ZJM-8 molecular sieve with water and stir evenly at room temperature; then transfer it to a hydrothermal reactor for crystallization reaction;

[0010] (3) The product of the crystallization reaction was washed and dried to obtain ZJM-11 molecular sieve.

[0011] As a preferred embodiment of the present invention, the mass ratio of ZJM-8 molecular sieve to water in the raw materials of the crystallization reaction is 1:0.1 to 0.8.

[0012] As a preferred embodiment of the present invention, the temperature is controlled at 100-220°C and the reaction time is controlled at 2-200 hours during the crystallization reaction.

[0013] As a preferred embodiment of the present invention, the molecular sieve is prepared by the method described in any one of claims 1 to 3.

[0014] The present invention also provides a phosphorus-aluminum-containing ZJM-11 molecular sieve. In the XRD diffraction data of the molecular sieve, the 2θ angle of the strongest peak in the range of 5 to 40° is 22.76±0.20°, and the corresponding diffraction peak intensity is 100%. The incident ray of the X-ray diffraction is Cu Kα1.

[0015] The present invention also provides a phosphorus-aluminum-containing ZJM-11 molecular sieve, which, in its X-ray diffraction pattern, includes at least the following X-ray diffraction peaks:

[0016]

[0017] The incident ray in the X-ray diffraction is Cu Kα1.

[0018] The present invention further provides the application of the aforementioned phosphorus-aluminum component ZJM-11 molecular sieve as a gas adsorbent.

[0019] As a preferred embodiment of the present invention, ZJM-11 molecular sieve is used for the adsorption and separation of hydrogen.

[0020] As a preferred embodiment of the present invention, the mixed gas containing hydrogen is passed through a tubular container filled with ZJM-11 molecular sieve, and the hydrogen is separated by adsorption of ZJM-11 molecular sieve.

[0021] Description of the invention principle:

[0022] According to the patent documents CN116199240B (ZL 2023 1 0000216.7, Preparation method and application of ZJM-8 molecular sieve containing phosphorus aluminum) and CN116002712B (ZL 2023 1 0000217.1, Preparation method and application of ZJM-9 molecular sieve containing phosphorus aluminum), ZJM-8 molecular sieve is a novel phosphorus aluminum molecular sieve characterized by a unique topological structure and exhibiting good thermal and chemical stability. Existing technology only discloses that its structure can be transformed into ZJM-9 molecular sieve with the same novel topological structure after water washing and secondary calcination, indicating that the material has structural tunability under specific post-treatment conditions, and both structures possess excellent gas adsorption capacity, showing potential application value in the fields of adsorption separation and catalysis.

[0023] However, researchers in the field generally consider novel, stable phosphorus-aluminum molecular sieves such as ZJM-8, which already possess a complete topological structure, to be the "end product" of synthesis. In the conventional understanding of those skilled in the art, due to the high crystallinity and stability of such molecular sieves, further hydrothermal crystallization is highly likely to cause structural collapse, decomposition, or transformation into amorphous impurities, making it virtually impossible to directionally and completely reconstruct them into another molecular sieve with a novel topological structure and good crystallinity. In particular, existing technologies (such as CN 116002712 B) reveal a specific post-processing route for converting ZJM-8 to ZJM-9 only through water washing and secondary calcination, while preserving the original molecular sieve framework structure, further solidifying the perception that its conversion pathways are limited.

[0024] X-ray diffraction (XRD) analysis is the definitive method for resolving the topological structure of molecular sieve crystals. Each known zeolite molecular sieve possesses a unique XRD characteristic spectrum, which can serve as a "fingerprint" for its identity. Therefore, to determine whether a molecular sieve has a novel structure, it is usually necessary to compare its experimental XRD spectrum with a standard spectral database of known structures; if no match is found, it confirms that it may possess an unprecedented topological configuration.

[0025] This application uses calcined ZJM-8 molecular sieve as the starting material and successfully transforms it into ZJM-11 molecular sieve through further hydrothermal crystallization. To clarify the structural properties of ZJM-11, we refined and systematically analyzed its XRD diffraction pattern. The results show that its spectral characteristics are significantly different from those of calcined ZJM-8 molecular sieve, confirming that they are different crystal structures. More importantly, by comparing with the International Zeolite Association database and other known aluminum phosphate molecular sieve structure data, no molecular sieves with known structures were found whose XRD patterns resembled those of ZJM-11. Figure 1 To.

[0026] Therefore, XRD analysis fully demonstrates that ZJM-11 is not a simple derivative or reproduction of any known aluminum phosphate molecular sieve in the prior art, but a novel aluminum phosphate molecular sieve with a completely new topological structure. Its novel crystal framework structure determines that it inevitably possesses unique physicochemical properties and application potential that distinguish it from ZJM-8 and ZJM-9. This research adds a new member to the molecular sieve structure family and is of great significance for expanding the structural diversity of porous materials and developing novel functional materials.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention successfully prepared a stable six-membered ring phosphorus aluminum molecular sieve ZJM-11 with a novel topological structure by using calcined ZJM-8 as a precursor and undergoing controlled hydrothermal conversion. This solves the technical problem of structural collapse and pore failure caused by the removal of guest species in traditional six-membered ring phosphorus aluminum molecular sieves.

[0029] 2. The ZJM-11 molecular sieve prepared by this invention has open and stable intrinsic channels, which can maintain structural integrity without the need for structure directing agents, thus laying the foundation for its application in the field of gas adsorption (especially small molecule gases such as hydrogen).

[0030] 3. The synthesis method of the present invention uses molecular sieves with specific structures as the starting point for transformation, providing a topological transformation path for synthesizing novel molecular sieves; the method is simple and has good reproducibility, providing a new strategy for the development of novel functional molecular sieve materials. Attached Figure Description

[0031] Figure 1 This is the XRD pattern of the ZJM-11 molecular sieve material prepared in Example 1 of this invention.

[0032] Figure 2 This is a SEM image of the ZJM-11 molecular sieve material prepared in Example 1 of this invention.

[0033] Figure 3 This is the H2 adsorption curve of ZJM-11 molecular sieve in Example 1. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it should be noted that the method of the present invention is not limited to the following examples and should not be construed as limiting the scope of protection of the present invention.

[0035] In the foregoing and following embodiments, the "calcined ZJM-8 molecular sieve" refers to an aluminum phosphate molecular sieve precursor with a specific crystal structure, the preparation method of which can be found in patent document CN116199240B (ZL 2023 10000216.7, A method for preparing and applying a phosphorus-aluminum ZJM-8 molecular sieve). After calcination, the framework structure is preserved and the template agent is removed. The key to the method of this invention is to use the calcined product with this specific structure as raw material and achieve further topological transformation to the new ZJM-11 structure through subsequent hydrothermal conditions.

[0036] Example 1

[0037] 1 g of calcined ZJM-8 molecular sieve was mixed with 0.2 g of water and stirred evenly at room temperature. The mixture was transferred to a hydrothermal reactor and reacted at 160 °C for 24 hours. The reaction product was washed, dried, and then ground into powder for XRD analysis. The molecular sieve was identified as a novel pure aluminum phosphate molecular sieve, ZJM-11. Figure 1 As shown in the electron microscope image, the molecular sieve is in the form of hexagonal blocks.

[0038] X-ray diffraction (XRD) tests were performed on the molecular sieve obtained in this embodiment to obtain its XRD diffraction pattern. In its XRD diffraction data, the 2θ angle of the strongest peak in the range of 5–40° is 22.76 ± 0.20°; the intensity of the diffraction peak at 2θ = 22.76° is taken as 100%.

[0039] The X-ray diffraction pattern should include at least the following X-ray diffraction peaks:

[0040]

[0041] The incident ray in the X-ray diffraction is Cu Kα1.

[0042] Example 2

[0043] 1 g of calcined ZJM-8 molecular sieve was mixed with 0.1 g of water and stirred evenly at room temperature. The mixture was transferred to a hydrothermal reactor and reacted at 220 °C for 2 hours. The reaction product was washed, dried, and then ground into powder for XRD analysis. The molecular sieve was confirmed to be a novel pure aluminum phosphate molecular sieve ZJM-11. Its XRD diffraction pattern and diffraction peak data were similar to those in Example 1. Electron micrographs showed that the molecular sieve was hexagonal blocky.

[0044] Example 3

[0045] 1 g of calcined ZJM-8 molecular sieve was mixed with 0.8 g of water and stirred evenly at room temperature. The mixture was transferred to a hydrothermal reactor and reacted at 100 °C for 100 hours. The reaction product was washed, dried, and then ground into powder for XRD analysis. The molecular sieve was confirmed to be a novel pure aluminum phosphate molecular sieve ZJM-11. Its XRD diffraction pattern and diffraction peak data were similar to those in Example 1. Electron micrographs showed that the molecular sieve was hexagonal blocky.

[0046] Example 4

[0047] 2g of calcined ZJM-8 molecular sieve was mixed with 0.8g of water and stirred evenly at room temperature. The mixture was transferred to a hydrothermal reactor and reacted at 120 °C for 200 hours. The reaction product was washed, dried, and then ground into powder for XRD analysis. The molecular sieve was confirmed to be a novel pure aluminum phosphate molecular sieve ZJM-11. Its XRD diffraction pattern and diffraction peak data were similar to those in Example 1. Electron micrographs showed that the molecular sieve was hexagonal blocky.

[0048] Example 5

[0049] 5 g of calcined ZJM-8 molecular sieve was mixed with 3 g of water and stirred evenly at room temperature. The mixture was transferred to a hydrothermal reactor and reacted at 180 °C for 24 hours. The reaction product was washed, dried, and then ground into powder for XRD analysis. The molecular sieve was confirmed to be a novel pure aluminum phosphate molecular sieve ZJM-11. Its XRD diffraction pattern and diffraction peak data were similar to those in Example 1. Electron micrographs showed that the molecular sieve was hexagonal blocky.

[0050] Application examples in H2 adsorption:

[0051] Take the ZJM-11 molecular sieve from Example 1 and use it as follows:

[0052] This experiment used a BSD-PH adsorption instrument; 858 mg of ZJM-11 molecular sieve was loaded into a sample tube and degassed under vacuum at 300 ℃ for 3 hours. Then, the H2 adsorption capacity of ZJM-11 was tested under conditions of 77 K and 10 MPa. The adsorption curve is shown below. Figure 3 As shown in the figure. Analysis of the adsorption curves showed that the adsorption capacity of H2 by the ZJM-11 molecular sieve at 77 K and 10 MPa was 18 cm⁻¹. 3 / g, the above results show that ZJM-11 molecular sieve has a significant adsorption capacity for hydrogen.

[0053] Based on the data from this adsorption test, it can be inferred that ZJM-11 molecular sieve can meet the requirements for industrial and special applications such as hydrogen purification, low-temperature hydrogen storage, and hydrogen isotope separation.

Claims

1. A method for preparing ZJM-11 molecular sieve containing phosphorus and aluminum, characterized in that, Includes the following steps: (1) ZJM-8 molecular sieve after calcination was prepared according to the method described in patent document CN116199240B; (2) Mix ZJM-8 molecular sieve with water and stir evenly at room temperature; then transfer it to a hydrothermal reactor for crystallization reaction; (3) The product of the crystallization reaction was washed and dried to obtain ZJM-11 molecular sieve.

2. The method according to claim 1, characterized in that, In the raw materials for the crystallization reaction, the mass ratio of ZJM-8 molecular sieve to water is 1:0.1 to 0.

8.

3. The method according to claim 1, characterized in that, During the crystallization reaction, the temperature is controlled at 100–220℃ and the reaction time is 2–200 hours.

4. A phosphorus-aluminum-containing ZJM-11 molecular sieve, characterized in that, The molecular sieve is prepared by the method described in any one of claims 1 to 3.

5. A phosphorus-aluminum-containing ZJM-11 molecular sieve, characterized in that, In the XRD diffraction data of this molecular sieve, the 2θ angle of the strongest peak in the range of 5–40° is 22.76 ± 0.20°, and the corresponding diffraction peak intensity is 100%; the incident line of the X-ray diffraction is Cu Kα1.

6. A ZJM-11 molecular sieve containing phosphorus and aluminum, characterized in that, The X-ray diffraction pattern of this molecular sieve includes at least the following X-ray diffraction peaks: ； The incident ray in the X-ray diffraction is Cu Kα1.

7. The application of the phosphorus-aluminum-containing ZJM-11 molecular sieve as described in any one of claims 4 to 6 as a gas adsorbent.

8. The application according to claim 7, characterized in that, The ZJM-11 molecular sieve is used for the adsorption and separation of hydrogen.

9. The application according to claim 7, characterized in that, The process involves passing a mixed gas containing hydrogen through a tubular container filled with ZJM-11 molecular sieves, where the hydrogen is adsorbed by the ZJM-11 molecular sieves to achieve separation.

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