A self-forming X-type molecular sieve foam material, its preparation method and application

Abstract

This invention discloses a self-forming X-type molecular sieve foam material, its preparation method, and its application, belonging to the field of green synthesis of molecular sieve foam materials. The preparation involves: 1) mixing calcined and activated metakaolinite and clinoptilolite powder to obtain a solid raw material, controlling the SiO2 / Al2O3 molar ratio to be 2.2-4; 2) mixing the solid raw material with an 8-12 mol / L sodium hydroxide solution at a mass ratio of 0.64-1.4:1; subsequently adding a foaming agent, stirring evenly, pouring into a mold, sealing, and crystallizing at 70-100℃ for 16-24 hours to obtain the self-forming X-type molecular sieve foam material. This invention utilizes only natural minerals, without adding chemical reagents as the silicon-aluminum source, to obtain a self-forming X-type molecular sieve foam without binders. This effectively avoids problems such as pore blockage, dilution of effective sites in the molecular sieve, and limited transport of guest molecules. Furthermore, it effectively utilizes natural minerals, reduces costs, and promotes industrial application.

Description

Technical Field

[0001] This invention belongs to the field of green synthesis of molecular sieve foam materials, specifically a self-forming X-type molecular sieve foam material, its preparation method, and its application. Background Technology

[0002] X-type molecular sieve (structure FAU, typical chemical formula Na) 86 [Al 86 Si 106 O 384 X-type molecular sieve (·264H2O) is an alumina-rich molecular sieve with a SiO2 / Al2O3 ratio of 2.2–3.0, second only to the lowest SiO2 / Al2O3 ratio (2), but its specific surface area is larger than that of type A molecular sieves. X-type molecular sieves have abundant Si-O-Al structures, are rich in exchangeable Na ions, and have a surface rich in OH functional groups. The pore size... Adsorption less than Any molecule can be used as a catalyst co-carrier, for co-adsorption of water and carbon dioxide, and for co-adsorption of water and hydrogen sulfide gas. It is also used in the drying of pharmaceutical and air compression systems. Different specialized varieties are available depending on the application.

[0003] Traditional synthesis of X-type molecular sieves involves a hydrothermal method using chemical reagents, which is costly. To address this issue, researchers both domestically and internationally have made some progress in molecular sieve synthesis techniques and methods, using natural mineral raw materials as silicon-aluminum sources to synthesize molecular sieves and reduce costs. For example, calcined kaolin can be used as a silicon-aluminum source, and X-type molecular sieves can be prepared by adding chemical reagents to adjust the silicon source composition. However, molecular sieves synthesized using chemical reagents or mineral raw materials via hydrothermal methods are usually extremely fine powders with diameters in the nanometer or micrometer range, making them difficult to apply directly. Except for a few applications such as detergents where powdered molecular sieves are required, industrial applications generally require molecular sieves to be shaped to meet the impact requirements of fluids and temperatures. The shaping process requires the addition of binders, resulting in granulation or extrusion into spherical or strip-shaped molecular sieves. However, the addition of binders can block the pores between molecular sieves to some extent, covering their active sites and limiting the amount of active components in the molecular sieve, ultimately leading to a decrease in the adsorption performance, catalytic performance, and thermal stability of the molecular sieve.

[0004] Meanwhile, existing methods for synthesizing molecular sieves using mineral raw materials as silica-alumina sources mostly employ a single mineral as a raw material combined with chemical silica-alumina reagents. It is difficult to synthesize molecular sieves using only two minerals. The difficulty lies in the fact that natural minerals are diverse, such as kaolinite, clinoptilolite, bentonite, palygorskite, attapulgite, illite, and diatomite. These mineral raw materials have complex compositions. For example, natural palygorskite contains not only palygorskite but also associated minerals such as mica, pyrophyllite, chlorite, kaolinite, pyrite, and rutile. Although these associated minerals contain varying proportions of silica-alumina, most are relatively stable and may not provide active silica-alumina to participate in the molecular sieve reaction, thus preventing the formation of crystalline molecular sieves. Utilizing a single mineral and supplementing it with silica-alumina reagents can improve the utilization rate of natural minerals and greatly broaden the types and varieties of molecular sieves synthesized from natural minerals. However, these chemical silica-alumina sources are obtained through complex reactions and separations, which are typically high-energy-consuming, high-polluting, and non-green processes. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a self-forming X-type molecular sieve foam material, its preparation method, and its application. It utilizes only natural minerals metakaolin and clinoptilolite, without adding any chemical reagents as silicon-aluminum sources, to obtain a self-forming X-type molecular sieve foam that does not require binders. This effectively avoids problems such as pore blockage, dilution of effective sites of molecular sieves, and limited transport of guest molecules.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for preparing a self-forming X-type molecular sieve foam material is provided, comprising the following steps:

[0008] 1) The calcined and activated metakaolin and clinoptilolite powder are mixed to obtain a solid raw material, wherein the molar ratio of SiO2 / Al2O3 in the solid raw material is controlled in the range of 2.2-4.0;

[0009] 2) Mix the solid raw material obtained in step 1) with the alkaline activator at a mass ratio of 0.64-1.40:1 and stir thoroughly. The alkaline activator is an 8-12 mol / L sodium hydroxide solution. Then add the foaming agent, stir thoroughly, pour into a mold and seal. Crystallize at 70-100℃ for 16-24 hours to obtain the self-formed X-type molecular sieve foam material.

[0010] According to the above scheme, in step 1), the calcined and activated metakaolin is prepared by calcining kaolin at 750-950℃ for 2-4 hours.

[0011] According to the above scheme, in step 1), the clinoptilolite powder is obtained by crushing and grinding natural clinoptilolite through a 60-mesh sieve.

[0012] According to the above scheme, the concentration of sodium hydroxide solution is 9-11 mol / L; the mass ratio of solid raw material to alkaline activator is 0.81-1.22:1.

[0013] According to the above scheme, in step 2), the alkaline activator is obtained by mixing sodium hydroxide and water in a mass ratio of 1:2.084-3.124 to obtain an 8-12 mol / L sodium hydroxide solution.

[0014] According to the above scheme, in step 2), the foaming agent is hydrogen peroxide; preferably, the concentration of hydrogen peroxide is 20-30 wt%.

[0015] According to the above scheme, in step 2), the foaming agent added is 2-6 wt% of the solid raw material.

[0016] A self-forming X-type molecular sieve foam material prepared by the above preparation method is provided.

[0017] According to the above scheme, the self-forming X-type molecular sieve foam material has a three-dimensional self-forming foam structure with a specific surface area of ​​129-230 m². 2 ·g -1 The compressive strength is 1.26-2.19 MPa.

[0018] This invention provides an application of the aforementioned self-forming X-type molecular sieve foam material as an adsorbent.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. This invention provides a method for preparing self-forming X-type molecular sieve foam material. By selecting two suitable natural minerals, kaolin and clinoptilolite, as the all-silica-alumina source, and controlling the appropriate silica-alumina ratio, along with suitable alkaline activator concentration and solid-liquid ratio, it is possible to ensure that the crystalline clinoptilolite and its associated minerals dissolve and participate in the formation of the X-type molecular sieve while maintaining suitable slurry fluidity, ensuring that the foam does not break during subsequent foaming. Finally, by using appropriate crystallization time and temperature, self-forming X-type molecular sieve foam is prepared. This invention directly obtains a three-dimensional self-forming foam structure without the need for binders, effectively avoiding problems such as pore blockage, dilution of effective sites of the molecular sieve, and limited transport of guest molecules. Moreover, the obtained foam has a large specific surface area and compressive strength, which is beneficial for the adsorption performance of the foam as an adsorbent and the recycling of the adsorbent, showing significant application prospects.

[0021] 2. The preparation method of the present invention is simple, mild, and does not require chemical reagents as silicon-aluminum sources. It can effectively utilize natural minerals, reduce costs, and is conducive to industrial application. Attached Figure Description

[0022] Figure 1 Photographs (a) and (b) of the self-forming X-type molecular sieve foam materials prepared in Examples 1-6.

[0023] Figure 2 XRD diffraction patterns of clinoptilolite and kaolin raw materials (a) and XRD diffraction patterns of self-forming X-type molecular sieve foams prepared in Examples 1-6 (b).

[0024] Figure 3 SEM images of the self-forming X-type molecular sieve foams prepared in Examples 1-6.

[0025] Figure 4 The XRD diffraction patterns of the foams prepared for comparative examples 1-3 are shown. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, and to enable those skilled in the art to better understand the process solutions of this invention, specific embodiments are as follows:

[0027] Example 1

[0028] A method for preparing a self-forming X-type molecular sieve foam material is provided, comprising the following steps:

[0029] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Kaolin was calcined at 750℃ for 2 hours to prepare metakaolin. XRF testing showed that the clinoptilolite powder contained 65% SiO2 and 15% Al2O3; the metakaolin powder contained 48% SiO2 and 44% Al2O3. Based on these compositions, clinoptilolite powder (26g) and metakaolin (14g) were mixed at a mass ratio of 7:13, so that the molar ratio of SiO2 / Al2O3 in the mixed raw materials was 4.0. This raw material is the raw material for preparing self-forming X-type molecular sieve foam.

[0030] (2) Preparation of sodium hydroxide solution: Water (29.06g) and sodium hydroxide (9.3g) were mixed in a mass ratio of 3.124:1, stirred evenly and cooled to room temperature to obtain the 8mol / L alkaline activator synthesized from molecular sieve.

[0031] (3) Preparation of self-forming X-type molecular sieve foam material: The solid raw material (40g) and alkaline activator (40g) are mixed at a mass ratio of 1:1.0 and stirred thoroughly. Then, 1.4g of 30wt% hydrogen peroxide foaming agent is added, stirred thoroughly, poured into a mold, sealed, and placed in an electric heating drying oven at 70℃ for 24h to crystallize, thus obtaining pure phase self-forming X-type molecular sieve foam environmentally friendly material. Figure 2 b) Specific surface area 129.73 m² 2 ·g -1 The compressive strength is 1.26 MPa.

[0032] Example 2

[0033] A method for preparing a self-forming X-type molecular sieve foam material is provided, comprising the following steps:

[0034] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Kaolin was calcined at 850℃ for 2 hours to prepare metakaolin. XRF testing showed that the clinoptilolite powder contained 65% SiO2 and 15% Al2O3; the metakaolin powder contained 48% SiO2 and 44% Al2O3. Based on these compositions, clinoptilolite powder (26g) and metakaolin (14g) were mixed at a mass ratio of 7:13, so that the molar ratio of SiO2 / Al2O3 in the mixed raw materials was 4.0. This raw material is the raw material for preparing self-forming X-type molecular sieve foam.

[0035] (2) Preparation of sodium hydroxide solution: Water (19.38g) and sodium hydroxide (9.3g) were mixed in a mass ratio of 2.084:1, stirred evenly and cooled to room temperature to obtain the 12mol / L alkaline activator synthesized from molecular sieve.

[0036] (3) Preparation of self-forming X-type molecular sieve foam material: Solid raw material (40g) and alkaline activator (28.68g) are mixed at a mass ratio of 1.4:1 and stirred thoroughly. Then, 1.6g of hydrogen peroxide (30wt%) foaming agent is added, stirred thoroughly, poured into a mold, sealed, and placed in an electric heating drying oven at 80℃ for 24h to crystallize, thus obtaining pure phase self-forming X-type molecular sieve foam environmentally friendly material. Figure 2 b) Specific surface area 169.81 m² 2 ·g -1 The compressive strength is 1.40 MPa.

[0037] Example 3

[0038] A method for preparing a self-forming X-type molecular sieve foam material is provided, comprising the following steps:

[0039] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Kaolin was calcined at 950℃ for 2 hours to prepare metakaolin. XRF testing showed that the clinoptilolite powder contained 65% SiO2 and 15% Al2O3; the metakaolin powder contained 48% SiO2 and 44% Al2O3. Based on these compositions, clinoptilolite powder (30g) and metakaolin (20g) were mixed at a mass ratio of 11:15, so that the molar ratio of SiO2 / Al2O3 in the mixed raw materials was 3.6. This raw material is the raw material for preparing self-forming X-type molecular sieve foam.

[0040] (2) Preparation of sodium hydroxide solution: Water (32.5g) and sodium hydroxide (11.7g) were mixed in a mass ratio of 2.77:1, stirred evenly and cooled to room temperature to obtain the 9mol / L alkaline activator synthesized from molecular sieve.

[0041] (3) Preparation of self-forming X-type molecular sieve foam material: Solid raw material (52g) and alkaline activator (44.2g) are mixed at a mass ratio of 1.17:1 and stirred thoroughly. Then, 1.8g of hydrogen peroxide (30wt%) foaming agent is added, stirred thoroughly, poured into a mold, sealed, and placed in an electric heating drying oven at 90℃ for 18h to obtain pure phase self-forming X-type molecular sieve foam environmentally friendly material. Figure 2 b) Specific surface area 189.26 m² 2 ·g -1 The compressive strength is 1.66 MPa.

[0042] Example 4

[0043] A method for preparing a self-forming X-type molecular sieve foam material is provided, comprising the following steps:

[0044] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Kaolin was calcined at 750℃ for 2 hours to prepare metakaolin. XRF testing showed that the clinoptilolite powder contained 65% SiO2 and 15% Al2O3; the metakaolin powder contained 48% SiO2 and 44% Al2O3. Based on these compositions, clinoptilolite powder (20g) and metakaolin (26g) were mixed to make the SiO2 / Al2O3 molar ratio of the mixed raw materials 3.0. This raw material is the raw material for preparing self-forming X-type molecular sieve foam.

[0045] (2) Preparation of sodium hydroxide solution: Mix water (41.67g) and sodium hydroxide (15g), stir evenly and cool to room temperature to obtain 9mol / L alkaline activator synthesized from molecular sieve.

[0046] (3) Preparation of self-forming X-type molecular sieve foam material: The solid raw material (69g) and alkaline activator (85g) are mixed at a mass ratio of 0.81:1 and stirred thoroughly. Then, 2.0g of 30wt% hydrogen peroxide foaming agent is added, stirred thoroughly, poured into a mold, sealed, and placed in an electric heating drying oven at 90℃ for 16h to obtain pure phase self-forming X-type molecular sieve foam environmentally friendly material. Figure 2 b) Specific surface area 182.36 m² 2 ·g -1 The compressive strength is 2.19 MPa.

[0047] Example 5

[0048] A method for preparing a self-forming X-type molecular sieve foam material is provided, comprising the following steps:

[0049] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Kaolin was calcined at 950℃ for 2 hours to prepare metakaolin. XRF testing showed that the clinoptilolite powder contained 65% SiO2 and 15% Al2O3; the metakaolin powder contained 48% SiO2 and 44% Al2O3. Based on these compositions, clinoptilolite powder (15g) and metakaolin (32.5g) were mixed to achieve a SiO2 / Al2O3 molar ratio of 2.6. This raw material is the material for preparing self-forming X-type molecular sieve foam.

[0050] (2) Preparation of sodium hydroxide solution: Mix water (55.28g) and sodium hydroxide (19.9g), stir evenly and cool to room temperature to obtain 9mol / L alkaline activator synthesized from molecular sieve.

[0051] (3) Preparation of self-forming X-type molecular sieve foam material: The solid raw material (48g) and alkaline activator (75g) are mixed at a mass ratio of 0.64:1 and stirred thoroughly. Then, 1.9g of 30wt% hydrogen peroxide foaming agent is added, stirred thoroughly, poured into a mold, sealed, and placed in an electric heating drying oven at 100℃ for 16h to crystallize, thus obtaining pure phase self-forming X-type molecular sieve foam environmentally friendly material. Figure 2 b) Specific surface area 179.88 m² 2 ·g -1 The compressive strength is 1.49 MPa.

[0052] Example 6

[0053] A method for preparing a self-forming X-type molecular sieve foam material is provided, comprising the following steps:

[0054] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Kaolin was calcined at 950℃ for 2 hours to prepare metakaolin. XRF testing showed that the clinoptilolite powder contained 65% SiO2 and 15% Al2O3; the metakaolin powder contained 48% SiO2 and 44% Al2O3. Based on these compositions, clinoptilolite powder (30g) and metakaolin (39g) were mixed to make the SiO2 / Al2O3 molar ratio of the mixed raw materials 3.0. This raw material is the raw material for preparing self-forming X-type molecular sieve foam.

[0055] (2) Preparation of sodium hydroxide solution: Mix water (41.67g) and sodium hydroxide (15g), stir evenly and cool to room temperature to obtain 9mol / L alkaline activator synthesized from molecular sieve.

[0056] (3) Preparation of self-forming X-type molecular sieve foam material: Solid raw material (69g) and alkaline activator (56.69g) are mixed at a mass ratio of 1.217:1.0 and stirred thoroughly. Then, 1.38g of hydrogen peroxide (30wt%) foaming agent is added, stirred thoroughly, poured into a mold, sealed, and placed in an electric heating drying oven for crystallization at 80℃ for 24h to obtain pure phase self-forming X-type molecular sieve foam environmentally friendly material. Figure 2 b) Specific surface area 229.13 m² 2 ·g -1 The compressive strength is 1.68 MPa.

[0057] Comparative Example 1

[0058] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Natural attapulgite was calcined at 750℃ for 2 hours to prepare activated attapulgite. The clinoptilolite powder (26g) and activated attapulgite (14g) were mixed at a mass ratio of 7:13 to make the molar ratio of SiO2 / Al2O3 of the mixed raw materials 4.0.

[0059] (2) Preparation of sodium hydroxide solution: Water (29.06g) and sodium hydroxide (9.3g) were mixed in a mass ratio of 3.124:1, stirred evenly and cooled to room temperature to obtain the basic activator synthesized from molecular sieve.

[0060] (3) Preparation of foam material: The solid raw material (40g) and the alkaline activator (40g) are mixed at a mass ratio of 1:1.0 and stirred evenly. Then, 1.4g of 30wt% hydrogen peroxide foaming agent is added, stirred evenly, poured into a mold and sealed. The mold is then placed in an electric heating drying oven and crystallized at 70℃ for 24h. The product contains sodalite, rutile, nepheline and a small amount of mica.

[0061] Comparative Example 2

[0062] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Natural attapulgite was calcined at 850℃ for 2 hours to prepare activated attapulgite. The clinoptilolite powder (26g) and activated attapulgite (14g) were mixed at a mass ratio of 7:13 to make the molar ratio of SiO2 / Al2O3 of the mixed raw materials 4.0.

[0063] (2) Preparation of sodium hydroxide solution: Water (19.38g) and sodium hydroxide (9.3g) were mixed at a mass ratio of 2.084:1, stirred evenly and cooled to room temperature to obtain the basic activator synthesized from molecular sieves.

[0064] (3) Preparation of foam material: The solid raw material (40g) and the alkaline activator (28.68g) were mixed at a mass ratio of 1.4:1 and stirred thoroughly. Then, 1.6g of hydrogen peroxide (30wt%) foaming agent was added, stirred evenly, poured into a mold and sealed. The mold was then placed in an electric heating drying oven and crystallized at 80℃ for 24h. The product contained sodalite, rutile, nepheline and a small amount of mica.

[0065] Comparative Example 3

[0066] (1) Preparation of mixed mineral raw materials: Natural clinoptilolite was crushed and ground through a 60-mesh sieve to obtain clinoptilolite powder. Natural attapulgite was calcined at 950℃ for 2 hours to prepare activated attapulgite. Clinoptilolite powder (30g) and activated attapulgite (20g) were mixed at a mass ratio of 11:15 to make the molar ratio of SiO2 / Al2O3 of the mixed raw materials 3.6.

[0067] (2) Preparation of sodium hydroxide solution: Water (32.5g) and sodium hydroxide (11.7g) were mixed in a mass ratio of 2.77:1, stirred evenly and cooled to room temperature to obtain the basic activator synthesized from molecular sieves.

[0068] (3) Preparation of foam material: The solid raw material (52g) and alkaline activator (44.2g) were mixed at a mass ratio of 1.17:1 and stirred thoroughly. Then, 1.8g of hydrogen peroxide (30wt%) foaming agent was added, stirred thoroughly, poured into a mold and sealed. The mold was then placed in an electric heating drying oven and crystallized at 90℃ for 18h. The product contained sodalite, rutile, nepheline and a small amount of mica.

[0069] Figure 1The images show (a) a photograph of the self-forming X-type molecular sieve foam material prepared in Examples 1-6 and (b) a photograph under an optical microscope. The figures show that the diameter of the self-forming X-type molecular sieve foam material is about 4 cm, which is consistent with the specifications of the mold used. The material does not shrink in size, and the pore size of the foam is about 1-2 mm, which is relatively uniform. The pore size increases relatively with the increase of the foaming agent content.

[0070] Figure 2 XRD diffraction patterns of clinoptilolite and kaolin raw materials (a) and XRD diffraction patterns of self-forming X-type molecular sieve foams prepared in Examples 1-6 (b). Figure 2 The natural clinoptilolite ore used in the experiment contains clinoptilolite, as well as feldspar, montmorillonite, illite, and kaolinite minerals. Kaolinite contains kaolinite minerals, but these minerals are not present in the prepared product, which is a pure phase X-type molecular sieve.

[0071] Figure 3 The images show SEM images of the self-forming X-type molecular sieve foams prepared in Examples 1-6. The images show that the prepared X-type molecular sieves are granular (quasi-octahedral) and uniformly distributed, which is a typical morphology of X-type molecular sieves.

[0072] Figure 4 XRD diffraction patterns of the foams prepared in Comparative Examples 1-3. The figures show that the products are a mixture of sodalite, rutile, nepheline, and mica, and X-type molecular sieves cannot be obtained.

[0073] As shown in Comparative Examples 1-3, there are many types of natural minerals. Although different natural minerals have similar chemical compositions, their mineral composition and active silica-alumina ratio have a significant impact on the synthesis of molecular sieves. Therefore, it is not possible to simply combine two minerals based on their chemical composition for the synthesis of self-forming X-type molecular sieve foam. This invention provides three sets of comparative examples. Based on the similarity of the silica-alumina ratio, natural attapulgite was used to replace natural kaolinite, and X-type molecular sieves were synthesized by mineral matching with natural clinoptilolite. However, the synthesis of X-type molecular sieve foam was unsuccessful.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. All technical scopes disclosed in the present invention are covered within the scope of protection of the present invention.

Claims

1. A method for preparing a self-forming X-type molecular sieve foam material, characterized in that, Includes the following steps: 1) The calcined and activated metakaolin and clinoptilolite powder are mixed to obtain a solid raw material, wherein the molar ratio of SiO2 / Al2O3 in the solid raw material is controlled in the range of 2.2-4.0; 2) Mix the solid raw material obtained in step 1) with the alkaline activator at a mass ratio of 0.64-1.40:1 and stir thoroughly. The alkaline activator is an 8-12 mol / L sodium hydroxide solution. Then add the foaming agent, stir thoroughly, pour into a mold and seal. Crystallize at 70-100℃ for 16-24 hours to obtain the self-formed X-type molecular sieve foam material.

2. The preparation method according to claim 1, characterized in that, In step 1), the calcined and activated metakaolin is prepared by calcining kaolin at 750-950℃ for 2-4 hours.

3. The preparation method according to claim 1, characterized in that, In step 1), the clinoptilolite powder is obtained by crushing and grinding natural clinoptilolite through a 60-mesh sieve.

4. The preparation method according to claim 1, characterized in that, The concentration of the sodium hydroxide solution is 9-11 mol / L.

5. The preparation method according to claim 1, characterized in that, The mass ratio of solid raw material to alkaline activator is 0.81-1.22:

1.

6. The preparation method according to claim 1, characterized in that, In step 2), the foaming agent is hydrogen peroxide foaming agent.

7. The preparation method according to claim 1, characterized in that, In step 2), the foaming agent is added at a mass of 2-6 wt% of the solid raw material.

8. A self-forming X-type molecular sieve foam material prepared by the preparation method according to any one of claims 1-7.

9. The self-forming X-type molecular sieve foam material according to claim 8, characterized in that, The self-forming X-type molecular sieve foam material has a three-dimensional self-forming foam structure with a specific surface area of ​​129-230 m². 2 ·g -1 The compressive strength is 1.26-2.19 MPa.

10. The use of the self-forming X-type molecular sieve foam material of claim 8 as an adsorbent.

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