NaY molecular sieve as well as preparation method and application thereof

Abstract

The invention provides a NaY molecular sieve and a preparation method and application thereof, and the preparation method comprises the following steps: mixing an aluminum source and a sodium source in a solvent to obtain a first mixture; adding a silicon source into the first mixture to obtain a second mixture; sequentially aging and crystallizing the second mixture to obtain a third mixture; and washing and drying the third mixture to obtain the NaY molecular sieve. According to the preparation method of the NaY molecular sieve provided by the invention, an organic template agent and a structure-directing agent are not needed, the synthesis process is simple, the energy consumption and the cost are remarkably reduced, and the prepared NaY molecular sieve has excellent CO2 adsorption performance.

Description

Technical Field

[0001] The present invention relates to the field of chemical engineering technology, specifically to the field of molecular sieves, and particularly to a NaY molecular sieve, a preparation method thereof, and an application thereof. Background Art

[0002] Due to its large pore diameter and high specific surface area (~400 m 2 / g - 1200 m 2 / g), the NaY molecular sieve (sodium Y-type molecular sieve) exhibits excellent performance in gas separation and adsorption processes, especially showing significant advantages in CO 2 capture and gas separation.

[0003] In the prior art, the synthesis methods of NaY molecular sieves mainly rely on organic template agents (such as tetramethylammonium hydroxide, tetrapropylammonium hydroxide, tetrapropylammonium hydroxide, N,N-dimethyl-1,3-propanediamine, etc.) and structure-directing agents. These organic additives play a key role in the synthesis process. By doping with organic template agents, the pore structure and crystal morphology of the molecular sieve can be effectively controlled to ensure the production of high-quality NaY molecular sieves.

[0004] CN107140656A discloses a preparation method of a mesoporous NaY-type zeolite molecular sieve, which includes mixing a silicon source, an aluminum source, and water at 25 - 35 °C, adjusting the pH to 9 - 12, dropping a NaY-type molecular sieve directing agent, and then adding an organic quaternary ammonium salt as a template agent drop by drop to obtain a silicate gel; removing the template agent. The molecular sieve of this invention has a crystallized pore wall structure.

[0005] CN109264743A discloses a preparation method of a small-crystalline high-silica-alumina ratio NaY molecular sieve. The method specifically includes the steps of synthesizing a directing agent, synthesizing a gel, aging, and crystallization. When synthesizing the directing agent, different silicon sources are selected and the synthesis conditions of the directing agent are changed. The process for preparing the small-crystalline high-silica-alumina ratio NaY molecular sieve of this invention is simple, and a NaY molecular sieve with a grain size of 100 - 250 nm and a silica-alumina ratio of about 5.5 can be prepared.

[0006] CN118561291A discloses a preparation method of a NaY molecular sieve with the characteristics of small crystals, including the preparation of a directing agent, the preparation of a synthesis gel, and hydrothermal crystallization. Among them, the synthesis gel is obtained by uniformly mixing a silicon source, an acidic aluminum salt solution, and water under stirring to obtain a silica-aluminum gel mixture, filtering the silica-aluminum gel mixture to obtain a gel cake; then uniformly mixing the gel cake with the directing agent.

[0007] However, the organic template itself is relatively expensive, and its dosage and reaction conditions need to be strictly controlled during the synthesis process, which increases the complexity and cost of the production process. Moreover, the organic template needs to be removed by high-temperature calcination or other chemical methods, which not only consumes a large amount of energy but also generates harmful gases and solid waste, imposing a significant burden on the environment.

[0008] Therefore, it is of great significance to develop a method for preparing NaY zeolite without template and structure-directing agent. Summary of the Invention

[0009] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a NaY zeolite and its preparation method and application. The preparation method of the NaY zeolite provided by the present invention does not require an organic template and a structure-directing agent, the synthesis process is simple, the energy consumption and cost are significantly reduced, and the prepared NaY zeolite has excellent CO 2 adsorption performance.

[0010] To achieve the purpose of this invention, the following technical solutions are adopted:

[0011] In the first aspect, the present invention provides a method for preparing a NaY zeolite, and the preparation method includes the following steps:

[0012] Mix an aluminum source and a sodium source in a solvent to obtain a first mixture; add a silicon source to the first mixture to obtain a second mixture; subject the second mixture to aging and crystallization in sequence to obtain a third mixture; wash and dry the third mixture to obtain the NaY zeolite.

[0013] The preparation method of the NaY zeolite provided by the present invention does not require an organic template and does not need to prepare a directing agent in advance, reducing the synthesis steps and the types of raw materials, simplifying the production process, and the prepared NaY zeolite has a relatively high specific surface area, showing excellent adsorption performance and good cycle stability at normal temperature and pressure. Through crystallization, the NaY zeolite has high crystallinity and a stable pore structure, ensuring the performance stability during long-term use.

[0014] Preferably, in the second mixture, the molar concentrations of the sodium source, the aluminum source, and the silicon source are each independently 0.01 mol / L - 10 mol / L.

[0015] Preferably, the sodium source includes any one or a combination of at least two of sodium hydroxide, sodium nitrate, sodium carbonate, sodium bicarbonate, sodium acetate, sodium chloride, or sodium silicate.

[0016] Preferably, the aluminum source includes any one or a combination of at least two of aluminum sulfate, aluminum chloride, aluminum nitrate, bauxite, aluminum hydroxide, chromite, aluminosilicate minerals, aluminosilicate sol, trimethylaluminum, or sodium metaaluminate.

[0017] Preferably, the silicon source includes any one or a combination of at least two of sodium silicate, silicon tetrachloride, tetraethyl orthosilicate, silica gel, silicon dioxide, sodium aluminosilicate, ammonium silicate, or colloidal silica.

[0018] Preferably, the solvent includes water / or ionic liquid.

[0019] Preferably, the composition of the third mixture includes Al 2 O 3 , Na 2 O, SiO 2 and solvent, and the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and solvent is 1:(0.2 - 200):(0.2 - 300):(2 - 10000).

[0020] Preferably, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and solvent is 1:(1.3 - 150):(1.6 - 250):(50 - 7000).

[0021] Preferably, the aging temperature is 0 °C - 100 °C, preferably 10 °C - 70 °C.

[0022] Preferably, the aging time is more than 1 h, preferably 1 h - 100 h.

[0023] Preferably, the crystallization temperature is 0 °C - 200 °C, preferably 40 °C - 120 °C.

[0024] Preferably, the crystallization time is more than 1 h, preferably 1 h - 100 h.

[0025] Preferably, the crystallization includes hydrothermal crystallization.

[0026] In the present invention, by optimizing the crystallization conditions and adopting the hydrothermal crystallization method, the molecular sieve has high crystallinity and a stable pore structure, ensuring the performance stability during long-term use.

[0027] Preferably, when adding the silicon source to the first mixture, it is necessary to carry out under stirring.

[0028] Preferably, the washing includes washing the third mixture until the pH of the wash water is 6-10.

[0029] Preferably, the temperature of the drying is 40°C - 200°C, preferably 60°C - 120°C.

[0030] Preferably, the time of the drying is more than 1 h, preferably 1 h - 100 h.

[0031] In a second aspect, the present invention provides a NaY molecular sieve, which is prepared by the preparation method described in the first aspect.

[0032] The NaY molecular sieve prepared by the preparation method of the present invention has a large specific surface area, showing excellent adsorption performance and good cycle stability.

[0033] In a third aspect, the present invention provides an application of the NaY molecular sieve described in the second aspect, and the NaY molecular sieve is applied to fields such as CO 2 adsorption, gas separation, air purification, and catalytic reaction.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The preparation method of the NaY molecular sieve provided by the present invention does not require an organic template agent or a seed crystal agent to be prepared in advance, reducing the synthesis steps and the types of raw materials, simplifying the production process, and the prepared NaY molecular sieve has a high specific surface area, showing excellent adsorption performance and good cycle stability at normal temperature and pressure. Through crystallization, the NaY molecular sieve has high crystallinity and a stable pore structure, ensuring the performance stability during long-term use.

[0036] (2) The NaY molecular sieve provided by the present invention has a relatively large specific surface area, showing excellent adsorption performance and good cycle stability.

[0037] (3) The NaY molecular sieve provided by the present invention is widely applied to fields such as CO 2 adsorption, gas separation, air purification, and catalytic reaction, and has a wide application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the adsorption isotherm diagram of the NaY molecular sieve prepared in Example 1.

[0039] Figure 2 is the N 2 adsorption and desorption isotherm diagram of the NaY molecular sieve prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0041] In a specific embodiment, the present invention provides a method for preparing NaY zeolite, and the preparation method includes the following steps:

[0042] Mix an aluminum source and a sodium source in a solvent to obtain a first mixture; add a silicon source to the first mixture to obtain a second mixture; subject the second mixture to aging and crystallization in sequence to obtain a third mixture; wash and dry the third mixture to obtain the NaY zeolite.

[0043] The method for preparing NaY zeolite provided by the present invention does not require an organic template agent nor a pre-prepared directing agent, reduces the synthesis steps and the types of raw materials, simplifies the production process, and the prepared NaY zeolite has a relatively high specific surface area and shows excellent adsorption performance and good cycle stability under normal temperature and pressure. Through crystallization, the NaY zeolite has high crystallinity and a stable pore structure, ensuring the performance stability during long-term use.

[0044] In some embodiments, in the second mixture, the molar concentrations of the sodium source, the aluminum source, and the silicon source are each independently 0.01 mol / L - 10 mol / L. For example, they can be 0.01 mol / L, 0.02 mol / L, 0.05 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.7 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, or 10 mol / L, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0045] In some embodiments, the sodium source includes any one or at least two combinations of sodium hydroxide, sodium nitrate, sodium carbonate, sodium bicarbonate, sodium acetate, sodium chloride, or sodium silicate. Typical but non-limiting combinations include the combination of sodium hydroxide and sodium nitrate, the combination of sodium carbonate and sodium bicarbonate, the combination of sodium acetate and sodium chloride, or the combination of sodium silicate and sodium hydroxide.

[0046] In some embodiments, the aluminum source includes any one or a combination of at least two of aluminum sulfate, aluminum chloride, aluminum nitrate, bauxite, aluminum hydroxide, aluminochromite, aluminosilicate minerals, aluminosilicate sol, trimethylaluminum, or sodium metaaluminate. Typical but non-limiting combinations include a combination of aluminum sulfate and aluminum chloride, a combination of aluminum nitrate and bauxite, a combination of aluminum hydroxide and aluminochromite, a combination of aluminosilicate minerals and aluminosilicate sol, a combination of trimethylaluminum and aluminum sulfate, or a combination of sodium metaaluminate and aluminum sulfate.

[0047] The bauxite used in the present invention contains gibbsite (Al(OH) 3 ) with a content of not less than 60%, boehmite (γ-AlO(OH)) with a content of 10-25%, and the rest being hematite (Fe 2 O 3 ) and silica (SiO 2 ) impurities (total amount < 5%); the aluminochromite contains 20%-30% of Al 2 O 3 , the rest being 8-15% of FeO content, 35-50% of Cr 2 O 3 content, and the balance being magnesium and silicon oxides, which need to be calcined pretreated at 600-800 °C to improve the reaction activity; the aluminosilicate minerals contain 40-60% of kaolin (Al 2 Si 2 O 5 (OH) 4 ), 15-30% of montmorillonite, and 10-20% of illite (Kal 2 (Si 3 Al)O 10 (OH) 2 ); the aluminosilicate sol is composed of sodium silicate (Na 2 SiO 3 ) and sodium metaaluminate (NaAlO 2 ) mixed in a SiO 2 / Al 2 O 3 molar ratio of 2:1-3:1, with a solid content of 8-12%, the pH value adjusted to 9-14, and the aging time ≥ 24 hours.

[0048] In some embodiments, the silicon source includes any one or a combination of at least two of sodium silicate, silicon tetrachloride, ethyl silicate, silica gel, silicon dioxide, sodium aluminosilicate, ammonium silicate, or colloidal silicon dioxide. Typical but non-limiting combinations include a combination of sodium silicate and silicon tetrachloride, a combination of ethyl silicate and silica gel, a combination of silicon dioxide and sodium aluminosilicate, or a combination of ammonium silicate and colloidal silicon dioxide.

[0049] In some embodiments, the solvent includes water and / or an ionic liquid.

[0050] The ionic liquids used in the present invention mainly include any one or a combination of at least two of 1-methyl-3-ethylimidazolium tetrafluoroborate, 1-methyl-3-ethylimidazolium chloride, 1-ethyl-3-methylimidazolium acetate, and tetrabutylammonium chloride. Typical but non-limiting combinations include the combination of 1-methyl-3-ethylimidazolium tetrafluoroborate and 1-methyl-3-ethylimidazolium chloride, the combination of 1-ethyl-3-methylimidazolium acetate and tetrabutylammonium chloride, the combination of 1-methyl-3-ethylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate, or the combination of tetrabutylammonium chloride and 1-methyl-3-ethylimidazolium tetrafluoroborate.

[0051] In some embodiments, the composition of the third mixture includes Al 2 O 3 , Na 2 O, SiO 2 and a solvent. The molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and the solvent is 1:(0.2 - 200):(0.2 - 300):(2 - 10000). For example, it can be 1:1.3:1.6:50, 1:150:250:7000, 1:0.2:0.2:2, 1:0.4:0.4:4, 1:0.6:0.8:6, 1:0.8:1:8, 1:1:2:10, 1:2:4:20, 1:4:6:40, 1:6:8:60, 1:8:10:80, 1:10:20:100, 1:20:40:200, 1:40:60:400, 1:60:80:600, 1:80:100:800, 1:100:120:1000, 1:120:150:2000, 1:140:200:4000, 1:160:250:6000, 1:180:280:8000, or 1:200:300:10000, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0052] In some embodiments, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and the solvent is 1:(1.3 - 150):(1.6 - 250):(50 - 7000).

[0053] In some embodiments, the aging temperature is 0°C - 100°C. For example, it can be 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 10°C - 70°C.

[0054] In some embodiments, the aging time is more than 1 h. For example, it can be 1 h, 2 h, 5 h, 10 h, 20 h, 40 h, 60 h, 80 h, 100 h, 200 h or 1000 h, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 1 h - 100 h.

[0055] In some embodiments, the crystallization temperature is 0°C - 200°C. For example, it can be 0°C, 10°C, 20°C, 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C or 200°C, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 40°C - 120°C.

[0056] In some embodiments, the crystallization time is more than 1 h. For example, it can be 1 h, 2 h, 5 h, 10 h, 20 h, 40 h, 60 h, 80 h, 100 h, 200 h or 1000 h, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 1 h - 100 h.

[0057] In some embodiments, the crystallization includes hydrothermal crystallization.

[0058] In the present invention, by optimizing the crystallization conditions and adopting the hydrothermal crystallization method, the molecular sieve has high crystallinity and a stable pore structure, ensuring its performance stability during long-term use.

[0059] In some embodiments, when adding the silicon source to the first mixture, it needs to be carried out under stirring. The stirring rate is not particularly limited as long as it can achieve uniform mixing of the silicon source and the first mixture. For example, it can be 200 rpm, 300 rpm, 500 rpm or 1000 rpm.

[0060] In some embodiments, the preparation method further includes adjusting the pH of the second mixture to more than 12. For example, it can be 12, 12.5, 13, 13.5 or 14, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0061] In the preparation method provided by the present invention, the pH regulator for adjusting the pH of the second mixture includes any one or a combination of at least two of sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate or ammonia water. Typical but non-limiting combinations include the combination of sodium hydroxide and sodium carbonate, the combination of sodium bicarbonate and ammonium carbonate, or the combination of ammonia water and sodium carbonate.

[0062] In some embodiments, the washing includes washing the third mixture until the pH of the wash water is 6-10. For example, the pH of the wash water can be 6, 7, 8, 9 or 10, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. The washing liquid used is a conventional washing liquid in the art, such as deionized water.

[0063] In some embodiments, the drying temperature is 40°C - 200°C. For example, it can be 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 60°C - 120°C.

[0064] In some embodiments, the drying time is more than 1 h. For example, it can be 1 h, 2 h, 5 h, 10 h, 20 h, 40 h, 60 h, 80 h, 100 h, 200 h or 1000 h, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 1 h - 100 h.

[0065] In another specific embodiment, the present invention provides a NaY molecular sieve, which is prepared by the preparation method described in the above specific embodiment.

[0066] The NaY molecular sieve prepared by the present invention has a large specific surface area, showing excellent adsorption performance and good cycle stability.

[0067] In another specific embodiment, the present invention provides an application of the NaY molecular sieve as described in the above another specific embodiment. The NaY molecular sieve is applied to fields such as 2 CO adsorption, gas separation, air purification and catalytic reaction.

[0068] Example 1

[0069] This example provides a preparation method of a NaY molecular sieve. The preparation method includes the following steps:

[0070] Sodium aluminate and sodium hydroxide are mixed in water to obtain a first mixture; colloidal silica is added to the first mixture under stirring at 500 rpm to obtain a second mixture; in the second mixture, the concentration of sodium aluminate is 0.427 mol / L, the concentration of sodium hydroxide is 2.625 mol / L, and the concentration of colloidal silica is 6.325 mol / L;

[0071] After the second mixture is aged at 45 °C for 24 h, it is transferred to a reaction vessel for hydrothermal crystallization. The temperature of hydrothermal crystallization is 100 °C and the time is 6 h to obtain a third mixture. In the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and water is 1:7.15:29.62:260.2; The third mixture is washed 3 times with water until the pH of the washing water is 7 and dried at 80 °C for 12 h to obtain the NaY molecular sieve.

[0072] The specific surface area of the NaY molecular sieve prepared in this example is 875 m 2 / g.

[0073] Example 2

[0074] This example provides a method for preparing a NaY molecular sieve, and the preparation method includes the following steps:

[0075] Sodium aluminate and sodium hydroxide are mixed in water to obtain a first mixture; colloidal silica is added to the first mixture under stirring at 500 rpm to obtain a second mixture; in the second mixture, the concentration of sodium aluminate is 0.643 mol / L, the concentration of sodium hydroxide is 3 mol / L, and the concentration of colloidal silica is 7.2 mol / L;

[0076] After the second mixture is aged at 60 °C for 30 h, it is transferred to a reaction vessel for hydrothermal crystallization. The temperature of hydrothermal crystallization is 110 °C and the time is 8 h to obtain a third mixture. In the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and water is 1:5.67:22.4:172.80; The third mixture is washed 3 times with water until the pH of the washing water is 7 and dried at 85 °C for 14 h to obtain the NaY molecular sieve.

[0077] The specific surface area of the NaY molecular sieve prepared in this example is 800 m 2 / g.

[0078] Example 3

[0079] This embodiment provides a method for preparing NaY molecular sieve, and the preparation method includes the following steps:

[0080] Sodium aluminate and sodium hydroxide are mixed in water to obtain a first mixture; under stirring at 700 rpm, colloidal silica is added to the first mixture to obtain a second mixture; in the second mixture, the concentration of aluminum sulfate is 0.5 mol / L, the concentration of sodium hydroxide is 2.5 mol / L, and the concentration of colloidal silica is 6.8 mol / L;

[0081] After the second mixture is aged at 60 °C for 40 h, it is transferred to a reaction vessel for hydrothermal crystallization. The temperature of hydrothermal crystallization is 105 °C and the time is 7 h to obtain a third mixture. In the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and water is 1:2.5:13.6:111.1; the third mixture is washed 3 times with water until the pH of the wash water is 9, and dried at 90 °C for 13 h to obtain the NaY molecular sieve.

[0082] The specific surface area of the NaY molecular sieve prepared in this embodiment is 750 m 2 / g.

[0083] Example 4

[0084] This embodiment provides a method for preparing NaY molecular sieve. Except that the concentration of aluminum sulfate is 0.3 mol / L, and in the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and water is 1:4.17:22.66:185.2, the rest are the same as in Example 3.

[0085] The specific surface area of the NaY molecular sieve prepared in this embodiment is 500 m 2 / g.

[0086] Example 5

[0087] This embodiment provides a method for preparing NaY molecular sieve. Except that the concentration of sodium hydroxide is 2 mol / L, and in the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and water is 1:4.11:22.44:172.80, the rest are the same as in Example 2.

[0088] The specific surface area of the NaY molecular sieve prepared in this example is 420 m 2 / g.

[0089] Example 6

[0090] This example provides a method for preparing a NaY molecular sieve. Except that the concentration of sodium hydroxide is 1 mol / L, in the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and water is 1:2.56:22.44:172.80, the rest are the same as in Example 2.

[0091] The specific surface area of the NaY molecular sieve prepared in this example is 400 m 2 / g.

[0092] Example 7

[0093] This example provides a method for preparing a NaY molecular sieve. Except that the concentration of sodium hydroxide is 0.5 mol / L, in the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and water is 1:1.78:22.44:172.80, the rest are the same as in Example 2.

[0094] The specific surface area of the NaY molecular sieve prepared in this example is 380 m 2 / g.

[0095] Example 8

[0096] This example provides a method for preparing a NaY molecular sieve. Except that the concentration of sodium hydroxide is 0.3 mol / L, in the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 and water is 1:1.46:22.44:172.80, the rest are the same as in Example 2.

[0097] The specific surface area of the NaY molecular sieve prepared in this example is 320 m 2 / g.

[0098] Example 9

[0099] This example provides a method for preparing a NaY molecular sieve. Except that the concentration of sodium hydroxide is 2 mol / L, in the third mixture, the molar ratio of Al 2 O3 , Na 2 O, SiO 2 Except that the molar ratio of them to water is 1:2:13.6:111.1, the rest are the same as in Example 3.

[0100] The specific surface area of the NaY zeolite prepared in this example is 510 m 2 / g.

[0101] Example 10

[0102] This example provides a method for preparing NaY zeolite. Except that the concentration of sodium hydroxide is 1 mol / L and in the third mixture, the molar ratio of Al 2 O 3 , Na 2 O, SiO 2 to water is 1:1:13.6:111.1, the rest are the same as in Example 3.

[0103] The specific surface area of the NaY zeolite prepared in this example is 290 m 2 / g.

[0104] Example 11

[0105] This example provides a method for preparing NaY zeolite. Except that aluminum sulfate is replaced with bauxite with an equal Al content, the rest are the same as in Example 3.

[0106] The specific surface area of the NaY zeolite prepared in this example is 320 m 2 / g.

[0107] Example 12

[0108] This example provides a method for preparing NaY zeolite, which includes the following steps:

[0109] Mix aluminum hydroxide and sodium bicarbonate in water to obtain a first mixture; add tetraethyl orthosilicate to the first mixture under stirring at 900 rpm to obtain a second mixture; in the second mixture, the concentration of aluminum hydroxide is 0.5 mol / L, the concentration of sodium bicarbonate is 72.5 mol / L, and the concentration of tetraethyl orthosilicate is 0.63 mol / L;

[0110] After the second mixture is aged at 15 °C for 75 h, it is transferred to a reaction vessel for hydrothermal crystallization. The temperature of hydrothermal crystallization is 80 °C and the time is 5 h to obtain a third mixture. In the third mixture, Al 2 O 3 , Na 2 O, SiO 2The molar ratio to water is 1:145:2.5:85; The third mixture is washed 5 times with water until the pH of the wash water is 7, and dried at 60 °C for 20 h to obtain the NaY molecular sieve.

[0111] The specific surface area of the NaY molecular sieve prepared in this example is 405 m 2 / g.

[0112] Example 13

[0113] This example provides a method for preparing a NaY molecular sieve, and the preparation method includes the following steps:

[0114] Mix aluminum chloride and sodium chloride in water to obtain a first mixture; Add colloidal silica to the first mixture under stirring at 500 rpm to obtain a second mixture; In the second mixture, the concentration of sodium chloride is 0.2 mol / L, the concentration of aluminum chloride is 39.6 mol / L, and the concentration of ammonium silicate is 0.25 mol / L;

[0115] After the second mixture is aged at 60 °C for 40 h, it is transferred to a reaction vessel for hydrothermal crystallization. The temperature of hydrothermal crystallization is 105 °C and the time is 7 h to obtain a third mixture. In the third mixture, Al 2 O 3 、Na 2 O、SiO 2 The molar ratio to water is 1:198:196:6500; The third mixture is washed 10 times with water until the pH of the wash water is 7, and dried at 120 °C for 4 h to obtain the NaY molecular sieve.

[0116] The specific surface area of the NaY molecular sieve prepared in this example is 380 m 2 / g.

[0117] Comparative Example 1

[0118] This comparative example provides a method for preparing a NaY molecular sieve. Except that sodium hydroxide is replaced with an equimolar amount of potassium hydroxide, the rest are the same as in Example 2.

[0119] The specific surface area of the NaY molecular sieve prepared in this comparative example is 416 m 2 / g.

[0120] Comparative Example 2

[0121] This comparative example provides a method for preparing a NaY molecular sieve. Except that sodium hydroxide is replaced with an equimolar amount of calcium hydroxide, the rest are the same as in Example 2.

[0122] The specific surface area of ​​the NaY molecular sieve prepared in this comparative example is 401m 2 / g.

[0123] Performance Test:

[0124] The specific surface area and CO 2 The adsorption performance was tested and the test results are shown in Table 1.

[0125] The specific surface area was tested using a BET specific surface area tester (JWGB-BK300, JWGB-BK300). 2 The adsorption capacity test uses JWGB-BK300 gas adsorption instrument to collect CO 2 Adsorption isotherm: the sample was degassed at 573 K for 10 h, and then its CO adsorption at 298 K and 1 bar was tested. 2 Adsorption amount.

[0126] The CO of the NaY molecular sieve prepared in Example 1 2 Adsorption isotherms and N 2 The adsorption-desorption isotherms were tested and the test results are shown in Figure 1 and Figure 2 .

[0127] Table 1

[0128] <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[CO 2 Adsorption capacity (mmol / g)]]> Example 1 875 6.5 Example 2 800 6 Example 3 750 5.1 Example 4 500 4.6 Example 5 420 4.1 Example 6 400 3.6 Example 7 380 3.4 Example 8 320 3.2 Example 9 510 4.4 Example 10 290 2.9 Example 11 320 5.1 Example 12 405 3.8 Example 13 380 3.5 Comparative Example 1 416 4.9 Comparative Example 2 401 3.8

[0129] According to the test results of Example 1 to Example 13, the present invention successfully prepares NaY molecular sieve without using an organic template and without pre-preparing a directing agent. The preparation method provided by the present invention reduces the synthesis steps and the types of raw materials, simplifies the production process, and the prepared NaY molecular sieve has a high specific surface area, and shows excellent adsorption performance and good cycle stability at room temperature and pressure. Through crystallization, the NaY molecular sieve has high crystallinity and a stable pore structure, ensuring its performance stability in long-term use.

[0130] According to the data results of Example 2 and Example 5 to Example 8, it can be determined that as the Na molar content decreases, the adsorption amount of carbon dioxide by the prepared NaY molecular sieve decreases.

[0131] Similarly, the data results of Example 3 and Example 9-Example 10 also prove that as the Na molar content decreases, the adsorption amount of carbon dioxide by the prepared NaY molecular sieve decreases.

[0132] When the aluminum source in Example 3 is changed to bauxite, according to the data results of Example 11, it can be determined that different aluminum sources have a great influence on the synthesis. In addition to alumina and hydrated alumina (such as boehmite and gibbsite), bauxite usually also contains a certain amount of impurities such as iron, silicon, and titanium. These impurities will affect the crystal phase formation of the material, change its structure, and thus reduce the CO 2 adsorption capacity; in addition, the solubility of bauxite is usually lower than that of high-purity aluminum sources (such as sodium aluminate, aluminum nitrate, etc.), resulting in uneven distribution of aluminum species during the synthesis process, which in turn affects the formation of the pore structure and leads to a decrease in the CO 2 adsorption amount.

[0133] From the data results of Example 2 and Comparative Examples 1-2, it can be seen that after replacing sodium hydroxide with potassium hydroxide and calcium hydroxide, cations other than Na + are introduced, resulting in a decrease in the performance of the prepared NaY molecular sieve.

[0134] The applicant declares that the above description is only a specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing NaY molecular sieve, characterized in that: The preparation method comprises the following steps: An aluminum source and a sodium source are mixed in a solvent to obtain a first mixture; a silicon source is added to the first mixture to obtain a second mixture; the second mixture is aged and crystallized in sequence to obtain a third mixture; the third mixture is washed and dried to obtain the NaY molecular sieve.

2. The preparation method according to claim 1, characterized in that In the second mixture, the molar concentrations of the sodium source, the aluminum source and the silicon source are independently 0.01 mol / L-10 mol / L.

3. The preparation method according to claim 1 or 2, characterized in that: The sodium source includes any one of sodium hydroxide, sodium nitrate, sodium carbonate, sodium bicarbonate, sodium acetate, sodium chloride or sodium silicate, or a combination of at least two thereof; Preferably, the aluminum source includes any one or a combination of at least two of aluminum sulfate, aluminum chloride, aluminum nitrate, bauxite, aluminum hydroxide, aluminum chrome ore, aluminum silicate minerals, aluminum silicate sol, trimethyl aluminum or sodium metaaluminate; Preferably, the silicon source includes any one of sodium silicate, silicon tetrachloride, ethyl silicate, silica gel, silicon dioxide, sodium aluminosilicate, ammonium silicate or colloidal silicon dioxide, or a combination of at least two thereof.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The third mixture comprises Al2O3, Na2O, SiO2 and a solvent, wherein the molar ratio of Al2O3, Na2O, SiO2 and the solvent is 1:(0.2-200):(0.2-300):(2-10000); Preferably, the molar ratio of Al2O3, Na2O, SiO2 and solvent is 1:(1.3-150):(1.6-250):(50-7000).

5. The preparation method according to any one of claims 1 to 4, characterized in that: The aging temperature is 0°C-100°C, preferably 10°C-70°C; Preferably, the aging time is more than 1 hour, preferably 1 hour to 100 hours.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The crystallization temperature is 0°C-200°C, preferably 40°C-120°C; Preferably, the crystallization time is more than 1 hour, preferably 1 hour to 100 hours; Preferably, the crystallization comprises hydrothermal crystallization.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The washing comprises washing the third mixture until the pH of the washing water is 6-10.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The drying temperature is 40°C-200°C, preferably 60°C-120°C; Preferably, the drying time is more than 1 hour, preferably 1 hour to 100 hours.

9. A NaY molecular sieve, characterized in that: The NaY molecular sieve is prepared by the preparation method according to any one of claims 1 to 8.

10. An application of the NaY molecular sieve as claimed in claim 9, characterized in that: The NaY molecular sieve is used in the fields of CO2 adsorption, gas separation, air purification and catalytic reaction.

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