Multi-element gas adsorbent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of adsorbents, in particular to a multi-element gas adsorbent as well as a preparation method and application thereof. The preparation method of the multi-element gas adsorbent provided by the invention is simple, economic and environment-friendly, and is suitable for industrial large-scale production. The prepared adsorbent is regular in morphology and rich in various active sites, and sulfur dioxide, nitrogen dioxide and ammonia gas in air can be effectively adsorbed. Compared with the prior art, the CHO-SBA-PEI multi-element gas adsorbent prepared by the preparation method disclosed by the invention combines a mesoporous structure (high specific surface area and regular pore channels) of SBA-15, amino active sites of PEI and aldehyde groups modified in the pore channels of SBA-15, not only realizes multi-element absorption of SO2, NO2 and NH3, but also has high adsorption capacity, and can effectively purify gas entering a hydrogen energy fuel cell. The preparation process is simple and controllable, does not need special equipment, is easy for large-scale production, and is suitable for industrial application of the hydrogen energy fuel cell air filter.

Description

Technical Field

[0001] This invention relates to the field of adsorbent technology, specifically to a multi-component gas adsorbent, its preparation method, and its application. Background Technology

[0002] Hydrogen fuel cells, as a highly efficient and clean energy conversion device, have broad application prospects in new energy vehicles, distributed power generation, and other fields. Their performance is highly dependent on the purity of the reactant gases, especially acidic gaseous pollutants in the air such as sulfur dioxide (SO2) and nitrogen dioxide (NO2). Even at low concentrations, these pollutants can poison the fuel cell cathode catalyst, degrade electrode performance, and significantly shorten the lifespan of the fuel cell stack.

[0003] Currently, commonly used adsorbents in hydrogen fuel cell air filters mainly include activated carbon and unmodified molecular sieves, but these have the following drawbacks: activated carbon has insufficient selective adsorption capacity for acidic gases and is easily affected by moisture, leading to a decrease in adsorption efficiency; traditional molecular sieves have fewer surface active sites, resulting in limited adsorption capacity for SO2, NO2, and NH3, making it difficult to meet the requirements of long-term operation. Therefore, developing a highly efficient and stable acidic gas adsorbent for hydrogen fuel cell applications is of great significance for ensuring fuel cell performance and extending its lifespan. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a multi-component gas adsorbent, its preparation method and application, wherein the multi-component gas adsorbent provided by the present invention has a high adsorption capacity for SO2 and NO2.

[0005] This invention provides a multi-element gas adsorbent, comprising:

[0006] Aldehyde-modified SBA-15 molecular sieve, wherein the aldehyde-modified SBA-15 molecular sieve comprises an SBA-15 molecular sieve and aldehyde groups connected to the inner surface of the pores of the SBA-15 molecular sieve.

[0007] Polyethyleneimine coated on the aldehyde-modified SBA-15 molecular sieve.

[0008] The multi-component gas adsorbent provided by this invention comprises an aldehyde-modified SBA-15 molecular sieve. The aldehyde-modified SBA-15 molecular sieve includes an SBA-15 molecular sieve and aldehyde groups connected to the inner surface of the pores of the SBA-15 molecular sieve. The aldehyde groups are located inside the channels of the SBA-15 molecular sieve and are uniformly distributed within the material framework, enabling highly selective chemisorption of ammonia based on the Schiff base reaction principle. Specifically, the aldehyde-modified SBA-15 molecular sieve of this invention is prepared from a triblock copolymer Pluronic P123, tetraethyl orthosilicate (TEOS), and an aldehyde silanizing agent. The triblock copolymer Pluronic P123 has the molecular formula EO20PO70EO20 and a molecular weight of 5800; the aldehyde silanizing agent is selected from 3-formylpropyltriethoxysilane.

[0009] The multi-component gas adsorbent provided by this invention further includes polyethyleneimine (PEI) coated on the aldehyde-modified SBA-15 molecular sieve. Specifically, the polyethyleneimine of this invention coats the exterior of the aldehyde-modified SBA-15 molecular sieve. The molecular weight of the polyethyleneimine of this invention is 250MW~1000MW. Based on the principle of acid-base neutralization reaction, the polyethyleneimine coating on the exterior of the aldehyde-modified SBA-15 molecular sieve enables the chemical adsorption of acidic gases such as sulfur dioxide and nitrogen dioxide.

[0010] This invention also provides a method for preparing a multi-component gas adsorbent, comprising the following steps:

[0011] S1) The triblock copolymer Pluronic P123, tetraethyl orthosilicate, and aldehyde silanizing agent were heated in hydrochloric acid solution and then template removal was performed to obtain aldehyde-modified SBA-15 molecular sieve.

[0012] S2) The aldehyde-modified SBA-15 molecular sieve obtained in step S1), polyethyleneimine, and methanol are mixed for 6 h to 10 h to obtain a multi-component gas adsorbent.

[0013] This invention first involves heating a triblock copolymer, Pluronic P123, tetraethyl orthosilicate, and an aldehyde silanizing agent in a hydrochloric acid solution. Specifically, Pluronic P123 is dissolved in a hydrochloric acid solution, followed by the addition of tetraethyl orthosilicate and the aldehyde silanizing agent, and then the reaction is carried out under heating. More specifically, a hydrochloric acid solution is prepared by mixing water and concentrated hydrochloric acid, and Pluronic P123 is dissolved in the solution. The solution is then stirred until clear, and tetraethyl orthosilicate and the aldehyde silanizing agent are added while stirring and heating. The heating temperature is 25°C to 70°C, preferably 25°C to 50°C, which prevents the precursor structure from collapsing during drying. The reaction time is 15 h to 30 h, preferably 20 h to 26 h.

[0014] In the heating reaction system of the present invention, the concentration of hydrochloric acid is 1.9 mol / L to 2.1 mol / L, preferably 2.0 mol / L, and the mass ratio of the triblock copolymer Pluronic P123, tetraethyl orthosilicate, and aldehyde silanizing agent is (8-12):(15-20):(2-5), preferably (9-11):(17-18):(2-4). In some embodiments of the present invention, (8-12) g of triblock copolymer Pluronic P123, (15-20) g of tetraethyl orthosilicate, (2-5) g of aldehyde silanizing agent, (50-70) mL of concentrated hydrochloric acid, and (290-330) g of water are mixed, and the final concentration of hydrochloric acid in the mixture is 1.9 mol / L to 2.1 mol / L. This mixture is then subjected to a heating reaction. The triblock copolymer and aldehyde silanizing agent described in this invention are the same as those described above, and will not be repeated here.

[0015] This invention involves heating a triblock copolymer Pluronic P123, tetraethyl orthosilicate, and an aldehyde silanizing agent in hydrochloric acid solution, followed by template removal treatment to obtain aldehyde-modified SBA-15 molecular sieve. Specifically, the template removal treatment involves stirring at 90°C to 100°C for 15 to 30 hours in a 30 wt% to 60 wt% H₂SO₄ solution. More specifically, after heating and filtering to obtain the reacted material, the material is dried and then stirred at 90°C to 100°C for 15 to 30 hours in a 30 wt% to 60 wt% H₂SO₄ solution for template removal, followed by washing, filtering, and drying to obtain the aldehyde-modified SBA-15 molecular sieve. Preferably, the template removal treatment involves stirring at 90°C to 100°C for 20 to 26 hours in a 40 wt% to 50 wt% H₂SO₄ solution. The template mentioned in this invention refers to a template agent, namely the triblock copolymer Pluronic P123.

[0016] In this invention, after obtaining the aldehyde-modified SBA-15 molecular sieve, the aldehyde-modified SBA-15 molecular sieve, polyethyleneimine, and methanol are mixed for 6 to 10 hours to obtain a multi-component gas adsorbent. Specifically, polyethyleneimine and methanol are mixed and stirred for 10 to 30 minutes, then the aldehyde-modified SBA-15 molecular sieve is added, and the mixture is stirred and mixed at room temperature for 6 to 10 hours, then dried to obtain the multi-component gas adsorbent. The room temperature mentioned in this invention refers to a temperature without artificial intervention, generally 25°C. The polyethyleneimine used in this invention is the same as described above and will not be repeated. The multi-component gas adsorbent obtained in this invention is the same as described above and will not be repeated.

[0017] The mass ratio of polyethyleneimine to the aldehyde-modified SBA-15 molecular sieve in this invention is (1:2) to (2:1). This range of ratios allows polyethyleneimine to be uniformly distributed on the aldehyde-modified SBA-15 molecular sieve, and the amine groups form a strong interaction with the acidic gas, thereby improving the diversity of adsorbed gases. The mass ratio of polyethyleneimine to methanol is (1:4) to (1:10).

[0018] The present invention also provides the application of any of the above-described multi-element gas adsorbents or the multi-element gas adsorbents prepared by any of the above-described methods as filter element adsorption materials in hydrogen fuel cell air filters.

[0019] This invention provides a multi-component gas adsorbent, its preparation method, and its applications. The preparation method of the multi-component gas adsorbent provided by this invention is simple, economical, and environmentally friendly, suitable for large-scale industrial production. The prepared adsorbent has a regular morphology and is rich in multiple active sites, which is beneficial for the effective adsorption of sulfur dioxide, nitrogen dioxide, and ammonia in the air. Compared with existing technologies, the CHO-SBA-PEI multi-component gas adsorbent prepared by this invention combines the mesoporous structure of SBA-15 molecular sieve (high specific surface area, regular pores), the amino active sites of PEI, and the aldehyde groups modified within the pores of SBA-15 molecular sieve. It not only achieves multi-component absorption of SO2, NO2, and NH3, but also has a high adsorption capacity, effectively purifying the gas entering hydrogen fuel cells. The preparation process is simple and controllable, requires no special equipment, is easy to scale up, and is suitable for the industrial application of hydrogen fuel cell air filters. Attached Figure Description

[0020] Figure 1 This is a transmission electron microscope (TEM) image of the cross-section of CHO-SBA-PEI prepared in Example 1 of this invention;

[0021] Figure 2 This is a planar transmission electron microscope image of CHO-SBA-PEI prepared in Example 1 of the present invention;

[0022] Figure 3 The image shows the XRD pattern of CHO-SBA-PEI in Embodiment 1 of the present invention. Detailed Implementation

[0023] This invention discloses a multi-component gas adsorbent, its preparation method, and its applications. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0024] The main materials used in this invention are as follows:

[0025] Tetraethyl orthosilicate (TEOS);

[0026] Aldehyde silane reagent: 3-Formylpropyltriethoxysilane (CHO-Si);

[0027] Concentrated hydrochloric acid (HCl): mass concentration 38%;

[0028] Concentrated sulfuric acid (H2SO4): mass concentration 98%;

[0029] Triblock copolymer Pluronic P123 (EO20PO70EO20, molecular weight = 5800, Aldrich).

[0030] Polyethyleneimine (PEI, (linear PEI with a MW of 423 from Aldrich));

[0031] The methanol is anhydrous methanol.

[0032] The present invention will be further described below with reference to the embodiments:

[0033] Example 1

[0034] 1. Synthesis of aldehyde-modified SBA-15: The raw materials were calculated according to the following ratio: 9.86 g of P123: 17.708 g of tetraethyl orthosilicate: 3.51 g of aldehyde silanizing reagent: 60 mL of concentrated hydrochloric acid: 310 g of pure water.

[0035] The specific synthesis steps are as follows: concentrated hydrochloric acid is dissolved in pure water to prepare 2M HCl, P123 is dissolved in 2M HCl, the solution is stirred until clear, TEOS and CHO-Si are slowly added at 40℃, and the mixture is stirred for 24 h.

[0036] 2. After filtering and drying the above product, the template was removed by stirring at 95°C for 24 h with 48 wt% H2SO4 solution, washed with water and filtered, and dried at 80°C for 12 h to obtain aldehyde-modified SBA-15 material (CHO-SBA-15).

[0037] 3. Dissolve 4.0 g of PEI in 32 g of methanol and stir for 15 minutes. Then add 4.0 g of CHO-SBA-15 and stir for 8 hours at room temperature. After drying, CHO-SBA-PEI is obtained.

[0038] Comparative Example 1

[0039] 1. Synthesis of aldehyde-modified SBA-15: The raw materials were calculated according to the following ratio: 9.86 g of P123: 17.708 g of tetraethyl orthosilicate: 3.51 g of aldehyde silanizing reagent: 60 mL of concentrated hydrochloric acid: 310 g of pure water.

[0040] The specific synthesis steps are as follows: concentrated hydrochloric acid is dissolved in pure water to prepare 2M HCl, P123 is dissolved in 2M HCl, the solution is stirred until clear, TEOS and CHO-Si are slowly added at 40℃, and the mixture is stirred for 24 h.

[0041] 2. After filtering and drying the above product, the template was removed by stirring at 95°C for 24 h with 48 wt% H2SO4 solution, washed with water and filtered, and dried at 80°C for 12 h to obtain the final product CHO-SBA material.

[0042] Comparative Example 2

[0043] 1. Synthesis of SBA-15: The raw materials were calculated according to the following ratio: 9.86 g of P123: 17.708 g of tetraethyl orthosilicate: 60 mL of concentrated hydrochloric acid: 310 g of pure water.

[0044] The specific synthesis steps are as follows: concentrated hydrochloric acid is dissolved in pure water to prepare 2M HCl, P123 is dissolved in 2M HCl, the solution is stirred until clear, TEOS is slowly added at 40℃ and stirred for 24 h.

[0045] 2. After filtering and drying the above product, the template was removed by stirring at 95°C for 24 h with 48 wt% H2SO4 solution, washed with water and filtered, and dried at 80°C for 12 h to obtain SBA-15 material (SBA-15).

[0046] 3. Dissolve 4.0 g of PEI in 32 g of methanol and stir for 15 minutes. Then add 4.0 g of SBA-15 and stir at room temperature for 8 hours. After drying, the final product SBA-PEI material is obtained.

[0047] Comparative Example 3

[0048] 1. Synthesis of SBA-15: The raw materials were calculated according to the following ratio: 9.86 g of P123: 17.708 g of tetraethyl orthosilicate: 60 mL of concentrated hydrochloric acid: 310 g of pure water.

[0049] The specific synthesis steps are as follows: concentrated hydrochloric acid is dissolved in pure water to prepare 2M HCl, P123 is dissolved in 2M HCl, the solution is stirred until clear, TEOS is slowly added at 40℃ and stirred for 24 h.

[0050] 2. After filtering and drying the above product, the template was removed by stirring at 95°C for 24 h with 48 wt% H2SO4 solution, washed with water and filtered, and dried at 80°C for 12 h to obtain the final product SBA-15 material.

[0051] The final product of Example 1 was imaged using transmission electron microscopy (TEM), and the results are as follows: Figure 1 and Figure 2 As shown, Figure 1 This is a transmission electron microscope (TEM) image of the cross-section of CHO-SBA-PEI prepared in Example 1 of this invention; Figure 2This is a planar transmission electron microscope image of the CHO-SBA-PEI prepared in Example 1 of this invention. Figure 1 and Figure 2 As shown, the CHO-SBA-PEI adsorbent has a two-dimensional hexagonal channel structure (P6mm space group) with a wall thickness of 9.8 nm, exhibiting typical SBA-15 structural characteristics.

[0052] X-ray analysis was performed on CHO-SBA-PEI from Example 1, and the results are as follows: Figure 3 As shown, Figure 3 The image shows the XRD pattern of CHO-SBA-PEI in Example 1 of this invention. The XRD results show that the obtained adsorbent has the typical peak of SBA-15.

[0053] The specific surface area, pore volume, and pore size of the final products obtained in Example 1 and Comparative Examples 1-3 were tested using a McTristar II 3030 surface area and micropore analyzer. The test results are recorded in Table 1.

[0054] Table 1

[0055]

[0056] The final products obtained in Example 1 and Comparative Examples 1-3 were respectively loaded into reactors, and sulfur dioxide, nitrogen dioxide, and ammonia gases were introduced, with the flow rate controlled at 300 m / s. 3 The adsorption efficiency was tested at / h, and the results are recorded in Table 2:

[0057] Table 2

[0058]

[0059] The efficiency at each time point in Table 2 represents the absorption rate. Analysis of the test results in Table 2 shows that the modification of CHO and PEI greatly improves the adsorption of ammonia and acid gases, respectively. This greatly helps in the adsorption of multi-polluting gases, changes the limitation of SBA in adsorbing single pollutants, and better protects the fuel cell system.

[0060] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A multi-component gas adsorbent, characterized by, The application relates to a multi-gas adsorbent, a preparation method thereof and application of the multi-gas adsorbent. The application relates to a multi-gas adsorbent, a preparation method thereof and application of the multi-gas adsorbent. The aldehyde-based SBA-15 molecular sieve is prepared from a triblock copolymer Pluronic P123, tetraethyl orthosilicate and an aldehyde-based silanization agent.

2. The multi-component gas adsorbent of claim 1, wherein, The aldehyde-based silanization agent is selected from 3-formylpropyltriethoxysilane.

3. The multi-component gas adsorbent of claim 2, wherein, The molecular weight of the polyethylene imine is 250MW-1000MW.

4. The multi-component gas adsorbent of claim 1, wherein, The application further relates to a preparation method of the multi-gas adsorbent.

5. A method of preparing a multi-component gas adsorbent, characterized by, S1) carrying out a heating reaction of a triblock copolymer Pluronic P123, tetraethyl orthosilicate, an aldehyde-based silanization agent in a hydrochloric acid solution, and then carrying out a template removal treatment to obtain an aldehyde-based SBA-15 molecular sieve; S2) mixing the aldehyde-based SBA-15 molecular sieve obtained in step S1), polyethylene imine and methanol for 6-10 hours to obtain the multi-gas adsorbent. In step S1), the aldehyde-based silanization agent is selected from 3-formylpropyltriethoxysilane.

6. The method of claim 5, wherein the plurality of gas adsorbents are prepared by a process comprising: In step S2), the molecular weight of the polyethylene imine is 250MW-1000MW.

7. The method of claim 5, wherein the plurality of gas adsorbents are prepared by a process comprising: In step S1), in the system of the heating reaction, the concentration of the hydrochloric acid is 1.9-2.1 mol / L, and the mass ratio of the triblock copolymer Pluronic P123, tetraethyl orthosilicate and the aldehyde-based silanization agent is (8-12):(15-20):(2-5).

8. The method of claim 5, wherein the plurality of gas adsorbents are prepared by a process comprising: In step S2), the mass ratio of the polyethylene imine and the aldehyde-based SBA-15 molecular sieve is (1:2)-(2:1), and the mass ratio of the polyethylene imine and the methanol is (1:4)-(1:10). In step S1), the temperature of the heating reaction is 25-70 DEG C, and the time of the heating reaction is 15-30 hours.

9. The method of claim 5, wherein the plurality of gas adsorbents are prepared by a process comprising: The template removal treatment is specifically stirring in a 30 wt%-60 wt% H2SO4 solution at 90-100 DEG C for 15-30 hours.

10. Application of the multi-gas adsorbent in any one of claims 1-4 or the multi-gas adsorbent obtained by the preparation method in any one of claims 5-9 as an adsorption material in a filter core of an air filter of a hydrogen energy fuel cell. ​

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