Zeolite molecular sieve for oxygen production molecular sieve and preparation method thereof
By compounding the 5A boiler molecule sieve and silicon dioxide, and modifying the shells of phosphate with phosphates on the surface branches, the existing boiler molecular sieve in the oxygen -making field has been solved Improve the effect of adsorption performance and oxygen -nitrogen separation performance.
Patent Information
- Application Number
- CN202411537809.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-01-24
- Estimated Expiration
- 2044-10-31
AI Technical Summary
The existing zeolite molecular sieves have problems in the field of oxygen production, such as the reduction in screening and separation selectivity, and the small pore size limits the mass transfer ability of the medium and affects the adsorption performance.
By combining 5A type zeolite molecular sieve with silica, a composite zeolite-silica molecular sieve is prepared, and chitosan modified with a phosphate group is grafted on its surface to form a zeolite molecular sieve for oxygen production.
Improving the surface area and adsorption performance of the molecular screen, enhanced the mechanical strength, improved the performance of the screening membrane, and improved the separation of oxygen and nitrogen.
Smart Images
Figure CN119034692B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of molecular sieve preparation, and in particular is a zeolite molecular sieve for oxygen production molecular sieve and a preparation method thereof. Background Art
[0002] Oxygen molecular sieve is a key component in oxygen generators, used to selectively adsorb impurities such as nitrogen in the air, thereby achieving oxygen separation and purification. The most commonly used molecular sieves are 5A zeolite molecular sieve and 13X molecular sieve.
[0003] Among them, zeolite molecular sieve has a regular microporous skeleton structure and a large specific surface area, which makes it widely used in gas separation, adsorption and catalysis. In oxygen generators, zeolite molecular sieves increase the concentration of oxygen by adsorbing nitrogen and other impurity gases in the air. However, zeolite molecular sieve membranes have defects that reduce their screening effect and separation selectivity; in addition, the pore size of zeolite molecular sieves is small, which limits the mass transfer capacity of the medium, thereby affecting the adsorption performance of the molecular sieve. Therefore, it is necessary to modify it and optimize the performance of zeolite molecular sieves, which is of great significance to improving its application in the field of oxygen production. Summary of the invention
[0004] In order to solve the above problems, the object of the present invention is to provide a zeolite molecular sieve for oxygen production molecular sieve and a preparation method thereof.
[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:
[0006] A zeolite molecular sieve for oxygen production molecular sieve is prepared by using 5A zeolite molecular sieve as core and silicon dioxide as shell to prepare composite zeolite-silicon dioxide molecular sieve, and then grafting a layer of chitosan modified with phosphate group on the surface of the composite zeolite-silicon dioxide molecular sieve.
[0007] The chitosan modified with phosphate groups is prepared according to the following method: chitosan and bis(4-aminophenyl)phosphate are added to an organic solvent 1, stirred and dispersed uniformly, 4-dimethylaminopyridine and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added thereto, and the mixture is reacted at 40-70° C. for 12-24 hours. After the reaction is completed, the mixture is filtered, and the filter cake is washed with acetone and water for 3-5 times respectively, and dried to obtain chitosan modified with phosphate groups.
[0008] The organic solvent 1 is dichloromethane, chloroform, tetrahydrofuran, acetone or acetonitrile.
[0009] The mass ratio of the chitosan, bis(4-aminophenyl) phosphate, organic solvent 1, 4-dimethylaminopyridine and 1-ethyl-(3-dimethylaminopropyl) carbodiimide is 1:5-10:20-30:5-10:4-8.
[0010] The method for preparing the zeolite molecular sieve for oxygen production molecular sieve comprises the following steps:
[0011] 1) Add 5A zeolite molecular sieve to deionized water, add hexadecyltrimethylammonium bromide, isopropanol and ammonia water, stir and disperse evenly, add ethyl orthosilicate, stir and react at 25-30°C for 12-24h, filter after the reaction is completed, wash the filter cake with water to pH 7, dry, and calcine at 500-600°C for 5-8h to obtain a composite zeolite-silica molecular sieve;
[0012] 2) Add the composite zeolite-silica molecular sieve and epoxy silane coupling agent prepared in step 1) into an organic solvent, then add chitosan modified with phosphate groups, stir and react for 12 to 24 hours, filter, wash and dry to obtain a zeolite molecular sieve for oxygen production molecular sieve.
[0013] The mass ratio of the 5A zeolite molecular sieve, deionized water, hexadecyltrimethylammonium bromide, isopropanol, ammonia water and tetraethyl orthosilicate in step 1) is 1:20-30:1-2:10-15:3-5:1-2.
[0014] The organic solvent in step 2) is toluene or tetrahydrofuran with a water content of less than 10 ppm.
[0015] The epoxy silane coupling agent in step 2) is KH-560 or Z-6040.
[0016] In step 2), the mass ratio of the composite zeolite-silica molecular sieve, epoxy silane coupling agent, organic solvent and chitosan modified with phosphate groups is 1:3-5:10-20:1-2.
[0017] The present invention also includes the application of the zeolite molecular sieve used for oxygen production molecular sieve in nitrogen and oxygen separation.
[0018] Compared with the prior art, the present invention has the following advantages:
[0019] The zeolite molecular sieve for oxygen production molecular sieve of the present invention is a novel porous material with zeolite as a core and silica as a shell prepared by compounding silica with zeolite molecular sieve. Firstly, the introduction of silica can adjust the pore structure of zeolite and increase the specific surface area of the molecular sieve, thereby increasing the adsorption performance of the molecular sieve; secondly, it can improve the mechanical strength of the zeolite molecular sieve and reduce defects such as cracks on the surface of the zeolite, thereby improving the performance of the zeolite molecular sieve membrane and improving its application performance in oxygen production.
[0020] The zeolite molecular sieve for oxygen production molecular sieve of the present invention has a layer of chitosan modified with phosphate groups grafted on the surface of silicon dioxide. The introduction of chitosan and phosphate groups can increase the adsorption and ion exchange capacity of the molecular sieve material and improve the adsorption of nitrogen and carbon dioxide. In addition, the introduced amino group can improve the adsorption capacity of carbon dioxide, thereby improving the oxygen production capacity of the molecular sieve.
[0021] The preparation method of the invention is simple, and the prepared zeolite molecular sieve for oxygen production molecular sieve has high strength and high adsorption capacity and good oxygen-nitrogen separation performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 This is a scanning electron microscope image of the composite zeolite-silicon dioxide molecular sieve prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0023] In order to better understand the technical solution of the present invention, the above content of the present invention is further described in detail below through specific implementation methods in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above content of the present invention belong to the scope of the present invention.
[0024] The 5A zeolite molecular sieve used in the following examples was purchased from Shanghai Epoxy Chemical Reagent Co., Ltd.
[0025] Example 1 Preparation of chitosan modified with phosphate groups:
[0026] 0.1 kg of chitosan and 0.75 kg of bis(4-aminophenyl)phosphate were added to 2.5 kg of tetrahydrofuran, and after being stirred and dispersed evenly, 0.7 kg of 4-dimethylaminopyridine and 0.6 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added thereto, and the mixture was reacted at 55° C. for 18 h. After the reaction was completed, the mixture was filtered off, and the filter cake was washed 4 times with acetone and water respectively, and dried to obtain chitosan modified with phosphate groups.
[0027] Preparation of zeolite molecular sieve for oxygen production molecular sieve:
[0028] 0.1 kg of 5A zeolite molecular sieve was added to 2.5 kg of deionized water, and then 0.15 kg of hexadecyltrimethylammonium bromide, 1.2 kg of isopropanol and 0.38 kg of ammonia water were added thereto. After stirring and dispersing evenly, 0.15 kg of ethyl orthosilicate was added thereto. The mixture was stirred and reacted at 28°C for 18 hours. After the reaction was completed, the mixture was filtered and the filter cake was washed with water until the pH value was 7. After drying, the mixture was calcined at 550°C for 7 hours to obtain a composite zeolite-silica molecular sieve. The 5A zeolite molecular sieve and the prepared composite zeolite-silica molecular sieve were analyzed by scanning electron microscope respectively. The detection spectrum thereof is shown as follows: Figure 1 shown. Figure 1 (a) is 5A type zeolite molecular sieve; (b) is composite zeolite-silica molecular sieve; Figure 1 It can be seen that the unmodified 5A zeolite molecular sieve has sharp edges and corners, while the surface of the composite zeolite-silica molecular sieve has rounded edges and corners due to the wrapping of silica, which indicates the formation of the core-shell structure of the composite zeolite-silica molecular sieve.
[0029] 0.1 kg of composite zeolite-silica molecular sieve and 0.42 kg of epoxy silane coupling agent KH-560 were added to 1.5 kg of toluene with a water content of less than 10 ppm, and then 0.15 kg of chitosan modified with phosphate groups was added thereto. The mixture was stirred for 18 hours, filtered, washed and dried to obtain a zeolite molecular sieve for oxygen production molecular sieve.
[0030] Example 2 Preparation of chitosan modified with phosphate groups:
[0031] 0.1 kg of chitosan and 0.5 kg of bis(4-aminophenyl)phosphate were added to 2 kg of dichloromethane, and after being stirred and dispersed evenly, 0.5 kg of 4-dimethylaminopyridine and 0.4 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added thereto, and the mixture was reacted at 40°C for 24 hours. After the reaction was completed, the mixture was filtered off, and the filter cake was washed three times with acetone and water respectively, and dried to obtain chitosan modified with phosphate groups.
[0032] Preparation of zeolite molecular sieve for oxygen production molecular sieve:
[0033] 0.1 kg of 5A zeolite molecular sieve was added to 2 kg of deionized water, and then 0.1 kg of hexadecyltrimethylammonium bromide, 1 kg of isopropanol and 0.3 kg of ammonia water were added thereto. After stirring and dispersing evenly, 0.1 kg of ethyl orthosilicate was added thereto. The mixture was stirred and reacted at 25°C for 24 hours. After the reaction was completed, the mixture was filtered and the filter cake was washed with water until the pH value was 7. After drying, the mixture was calcined at 500°C for 8 hours to obtain a composite zeolite-silica molecular sieve.
[0034] 0.1 kg of composite zeolite-silica molecular sieve and 0.3 kg of epoxy silane coupling agent KH-560 were added to 1 kg of toluene with a water content of less than 10 ppm, and then 0.1 kg of chitosan modified with phosphate groups was added thereto. The mixture was stirred for 12 hours, filtered, washed and dried to obtain a zeolite molecular sieve for oxygen production molecular sieve.
[0035] Example 3 Preparation of chitosan modified with phosphate groups:
[0036] 0.1 kg of chitosan and 0.6 kg of bis(4-aminophenyl)phosphate were added to 2.2 kg of chloroform, and after being stirred and dispersed evenly, 0.6 kg of 4-dimethylaminopyridine and 0.5 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added thereto, and the mixture was reacted at 50°C for 20 hours. After the reaction was completed, the mixture was filtered off, and the filter cake was washed 5 times with acetone and water respectively, and dried to obtain chitosan modified with phosphate groups.
[0037] Preparation of zeolite molecular sieve for oxygen production molecular sieve:
[0038] 0.1 kg of 5A zeolite molecular sieve was added to 2.1 kg of deionized water, and then 0.12 kg of hexadecyltrimethylammonium bromide, 1.1 kg of isopropanol and 0.35 kg of ammonia water were added thereto. After stirring and dispersing evenly, 0.12 kg of ethyl orthosilicate was added thereto. The mixture was stirred and reacted at 26° C. for 22 hours. After the reaction was completed, the mixture was filtered and the filter cake was washed with water until the pH value was 7. After drying, the mixture was calcined at 520° C. for 7.5 hours to obtain a composite zeolite-silica molecular sieve.
[0039] 0.1 kg of composite zeolite-silica molecular sieve and 0.35 kg of epoxy silane coupling agent Z-6040 were added to 1.2 kg of tetrahydrofuran with a water content of less than 10 ppm, and then 0.12 kg of chitosan modified with phosphate groups was added thereto. The reaction was stirred for 14 hours, filtered, washed, and dried to obtain a zeolite molecular sieve for oxygen production molecular sieve.
[0040] Example 4 Preparation of chitosan modified with phosphate groups:
[0041] 0.1 kg of chitosan and 0.9 kg of bis(4-aminophenyl)phosphate were added to 2.8 kg of acetonitrile, and after being stirred and dispersed evenly, 0.9 kg of 4-dimethylaminopyridine and 0.7 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added thereto, and the mixture was reacted at 65°C for 15 hours. After the reaction was completed, the mixture was filtered off, and the filter cake was washed 5 times with acetone and water respectively, and dried to obtain chitosan modified with phosphate groups.
[0042] Preparation of zeolite molecular sieve for oxygen production molecular sieve:
[0043] 0.1 kg of 5A zeolite molecular sieve was added to 2.8 kg of deionized water, and then 0.18 kg of hexadecyltrimethylammonium bromide, 1.4 kg of isopropanol and 0.42 kg of ammonia water were added thereto. After stirring and dispersing evenly, 0.18 kg of ethyl orthosilicate was added thereto. The mixture was stirred and reacted at 26° C. for 15 h. After the reaction was completed, the mixture was filtered and the filter cake was washed with water until the pH value was 7. After drying, the mixture was calcined at 570° C. for 6 h to obtain a composite zeolite-silica molecular sieve.
[0044] 0.1 kg of composite zeolite-silica molecular sieve and 0.45 kg of epoxy silane coupling agent KH-560 were added to 1.8 kg of tetrahydrofuran with a water content of less than 10 ppm, and then 0.18 kg of chitosan modified with phosphate groups was added thereto. The mixture was stirred for reaction for 20 hours, filtered, washed and dried to obtain a zeolite molecular sieve for oxygen production molecular sieve.
[0045] Example 5 Preparation of chitosan modified with phosphate groups:
[0046] 0.1 kg of chitosan and 1 kg of bis(4-aminophenyl)phosphate were added to 3 kg of acetonitrile, and after being stirred and dispersed evenly, 1 kg of 4-dimethylaminopyridine and 0.8 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added thereto, and the mixture was reacted at 70°C for 12 hours. After the reaction was completed, the mixture was filtered off, and the filter cake was washed 5 times with acetone and water respectively, and dried to obtain chitosan modified with phosphate groups.
[0047] Preparation of zeolite molecular sieve for oxygen production molecular sieve:
[0048] 0.1 kg of 5A zeolite molecular sieve was added to 3 kg of deionized water, and then 0.2 kg of hexadecyltrimethylammonium bromide, 1.5 kg of isopropanol and 0.5 kg of ammonia water were added thereto. After stirring and dispersing evenly, 0.2 kg of ethyl orthosilicate was added thereto. The mixture was stirred and reacted at 30°C for 12 hours. After the reaction was completed, the mixture was filtered and the filter cake was washed with water until the pH value was 7. After drying, the mixture was calcined at 600°C for 5 hours to obtain a composite zeolite-silica molecular sieve.
[0049] 0.1 kg of composite zeolite-silica molecular sieve and 0.5 kg of epoxy silane coupling agent KH-560 were added to 2 kg of tetrahydrofuran with a water content of less than 10 ppm, and then 0.2 kg of chitosan modified with phosphate groups was added thereto. The mixture was stirred for reaction for 24 hours, filtered, washed and dried to obtain a zeolite molecular sieve for oxygen production molecular sieve.
[0050] Example 6 Preparation of chitosan modified with phosphate groups:
[0051] 0.1 kg of chitosan and 0.7 kg of bis(4-aminophenyl)phosphate were added to 3 kg of acetonitrile, stirred and dispersed evenly, and then 1 kg of 4-dimethylaminopyridine and 0.4 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added thereto, and the mixture was reacted at 70°C for 24 hours. After the reaction was completed, the mixture was filtered off, and the filter cake was washed three times with acetone and water respectively, and dried to obtain chitosan modified with phosphate groups.
[0052] Preparation of zeolite molecular sieve for oxygen production molecular sieve:
[0053] 0.1 kg of 5A zeolite molecular sieve was added into 2.9 kg of deionized water, and then 0.1 kg of hexadecyltrimethylammonium bromide, 1.5 kg of isopropanol and 0.45 kg of ammonia water were added thereto. After being stirred and dispersed evenly, 0.15 kg of ethyl orthosilicate was added thereto. The mixture was stirred and reacted at 30° C. for 24 h. After the reaction was completed, the mixture was filtered and the filter cake was washed with water until the pH value was 7. After being dried, the mixture was calcined at 500° C. for 5 h to obtain a composite zeolite-silica molecular sieve.
[0054] 0.1 kg of composite zeolite-silica molecular sieve and 0.4 kg of epoxy silane coupling agent KH-560 were added to 1.5 kg of tetrahydrofuran with a water content of less than 10 ppm, and then 0.2 kg of chitosan modified with phosphate groups was added thereto. The mixture was stirred for 12 hours, filtered, washed and dried to obtain a zeolite molecular sieve for oxygen production molecular sieve.
[0055] The composite zeolite-silica molecular sieves prepared in Examples 1 to 6 were analyzed using a Micromeritics TristarII 3020 fully automatic specific surface area and porosity analyzer, and the comparative example was a 5A zeolite molecular sieve, and the results are shown in Table 1. It can be seen from the results in Table 1 that compared with the unmodified 5A zeolite molecular sieve, the composite zeolite-silica molecular sieve prepared in the present invention has an increased specific surface area and pore size due to the encapsulation of silica.
[0056] Table 1 Specific surface parameters of composite zeolite-silicon dioxide molecular sieves prepared in Examples 1 to 6
[0057]
[0058] The performance of the oxygen-generating molecular sieve prepared in Examples 1 to 6 was tested by the volume adsorption method at 25°C, 101.325×10 3 The adsorption and separation capacity of the molecular sieve was tested at 1.5477 Pa, and the test results are shown in Table 2. As can be seen from the results in Table 2, the zeolite molecular sieve for oxygen production prepared by the present invention has a new porous material with zeolite as the core and silica as the shell prepared by compounding silica and zeolite molecular sieve, which increases the adsorption capacity of the molecular sieve, and at the same time, a layer of chitosan modified with phosphate groups is grafted on the surface of silica, which further increases the nitrogen adsorption capacity of the molecular sieve. Compared with the comparative example, it has a larger oxygen-nitrogen separation coefficient and has good application prospects in nitrogen-oxygen separation.
[0059] Table 2 Adsorption and separation results of zeolite molecular sieves for oxygen production prepared in Examples 1 to 6
[0060]
[0061] Although the above describes the specific implementation methods of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.
Claims
1. A zeolite molecular sieve for oxygen production molecular sieve, characterized in that: The composite zeolite-silicon dioxide molecular sieve is prepared by using 5A zeolite molecular sieve as the core and silicon dioxide as the shell, and then a layer of chitosan modified with phosphate groups is grafted on the surface of the composite zeolite-silicon dioxide molecular sieve. The chitosan modified with phosphate groups is prepared according to the following method: chitosan and bis(4-aminophenyl)phosphate are added to an organic solvent 1, stirred and dispersed uniformly, 4-dimethylaminopyridine and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added thereto, and the mixture is reacted at 40-70° C. for 12-24 hours. After the reaction is completed, the mixture is filtered, and the filter cake is washed with acetone and water for 3-5 times respectively, and dried to obtain chitosan modified with phosphate groups.
2. The zeolite molecular sieve for oxygen production according to claim 1, characterized in that: The organic solvent 1 is dichloromethane, chloroform, tetrahydrofuran, acetone or acetonitrile.
3. The zeolite molecular sieve for oxygen production according to claim 1, characterized in that: The mass ratio of the chitosan, bis(4-aminophenyl) phosphate, organic solvent 1, 4-dimethylaminopyridine and 1-ethyl-(3-dimethylaminopropyl) carbodiimide is 1:5-10:20-30:5-10:4-8.
4. The method for preparing the zeolite molecular sieve for oxygen production molecular sieve according to claim 1, characterized in that: The following steps are involved: 1) Add 5A zeolite molecular sieve to deionized water, add hexadecyltrimethylammonium bromide, isopropanol and ammonia water, stir and disperse evenly, add ethyl orthosilicate, stir and react at 25-30°C for 12-24h, filter after the reaction is completed, wash the filter cake with water to pH 7, dry, and calcine at 500-600°C for 5-8h to obtain a composite zeolite-silica molecular sieve; 2) Add the composite zeolite-silica molecular sieve and epoxy silane coupling agent prepared in step 1) into an organic solvent, then add chitosan modified with phosphate groups, stir and react for 12 to 24 hours, filter, wash and dry to obtain a zeolite molecular sieve for oxygen production molecular sieve.
5. The method for preparing the zeolite molecular sieve for oxygen production molecular sieve according to claim 4, characterized in that: The mass ratio of the 5A zeolite molecular sieve, deionized water, hexadecyltrimethylammonium bromide, isopropanol, ammonia water and tetraethyl orthosilicate in step 1) is 1:20-30:1-2:10-15:3-5:1-2.
6. The method for preparing the zeolite molecular sieve for oxygen production molecular sieve according to claim 4, characterized in that: The organic solvent in step 2) is toluene or tetrahydrofuran with a water content of less than 10 ppm.
7. The method for preparing a zeolite molecular sieve for oxygen production according to claim 4, characterized in that: The epoxy silane coupling agent in step 2) is KH-560 or Z-6040.
8. The method for preparing the zeolite molecular sieve for oxygen production molecular sieve according to claim 4, characterized in that: In step 2), the mass ratio of the composite zeolite-silica molecular sieve, epoxy silane coupling agent, organic solvent and chitosan modified with phosphate groups is 1:3-5:10-20:1-2.
9. Use of the zeolite molecular sieve for oxygen production molecular sieve according to claim 1 in nitrogen and oxygen separation.