Preparation method of high-silicon mesoporous Y-type molecular sieve

Abstract

The invention relates to a method for preparing a high-silicon mesoporous Y-type molecular sieve, which comprises the following steps: (1) mixing a low-silicon Y-type molecular sieve with an aqueous solution of a pretreatment agent, and treating to obtain a mixture A, the pretreatment agent being one or more of alkali, acid and alkali metal fluorides; (2) washing and drying the obtained mixture A to obtain a powdery molecular sieve B; (3) performing ion exchange on the obtained powdery molecular sieve B in a sodium salt solution to obtain a mixture C; (4) washing and drying the obtained mixture C to obtain a powdery molecular sieve D; and (5) preparing a regrowth mother solution, mixing the powdery molecular sieve D obtained in the step (4) with the mother solution, transferring into a crystallization kettle for crystallization treatment, washing, filtering and drying to obtain the high-silicon mesoporous Y-type molecular sieve. Compared with the original NaY molecular sieve, the molecular sieve obtained by the treatment has obviously improved mesoporous volume and silica-alumina ratio. According to the method, the commercial molecular sieve is used as a raw material for secondary modification, and the synthesis route of the high-silicon mesoporous Y-type molecular sieve is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular sieve synthesis, and in particular relates to a method for preparing a high-silicon mesoporous Y-type molecular sieve by adopting a dissolution-regrowth process. Background Art

[0002] Zeolite molecular sieves have excellent properties such as unique porous structure, certain strength of acidity, shape selectivity, superior (water) thermal stability, etc., and are widely used as catalysts in various chemical reaction processes, such as catalytic cracking (FCC) and methanol to olefins (MTO). The microporous structure (≤1nm) inside the molecular sieve gives it unique activity and shape selectivity, but this also makes it impossible for macromolecular reactants to contact the active sites inside the molecular sieve, reducing the catalytic activity of the molecular sieve. Introducing mesopores into molecular sieve crystals can effectively solve this problem.

[0003] The Y-type molecular sieve with FAU topology is one of the important members of the molecular sieve industry. The Y-type molecular sieve has a twelve-membered ring structure, with an opening diameter of 1.2nm and an internal cavity diameter of 0.74nm. Because it has a super cage structure that is easily accessible to reactant molecules and has good hydrothermal stability, the Y-type molecular sieve and its series products have been the most commonly used catalysts in FCC since the 1960s.

[0004] Many scholars have devoted themselves to introducing mesopores into Y-type molecular sieves. CN 1031722082 B discloses a method for synthesizing a NaY molecular sieve with a mesoporous structure, wherein the hydrothermally synthesized NaY molecular sieve is subjected to ion exchange to obtain an ammonium-type molecular sieve, and then subjected to organic acid treatment, alkali treatment, and ammonium nitrate treatment to obtain a Y-type molecular sieve with high crystallinity and containing mesopores. However, the silicon-aluminum ratio of the product is relatively low, and the hydrothermal stability is poor. The silicon-aluminum ratio and pore structure of the molecular sieve are crucial to the stability of the catalyst, product distribution, and catalytic activity.

[0005] However, for Y-type molecular sieves, it is very difficult to directly synthesize molecular sieves with a silicon-aluminum ratio greater than 3. They are usually synthesized under hydrothermal conditions using a structure directing agent (OSDA) or after dealumination.

[0006] In 1991, Delprato et al. first used crown ether as a structure-directing agent to directly hydrothermally synthesize high-silicon Y-type molecular sieves with a silicon-aluminum ratio of 3-5. However, the high price and toxicity of crown ethers limit their widespread industrial application. The main active ingredient of industrial cracking catalysts is ultrastable Y (USY), which is prepared by post-synthesis dealumination using conventional Y-type molecular sieves as precursors. Although the dealumination process can enhance the framework silicon-aluminum ratio and (hydro)thermal stability and introduce a mesoporous structure, this dealumination process can cause a small amount of framework collapse, thereby blocking the molecular sieve pores, as well as low crystallinity in ultra-stabilized USY.

[0007] High-silicon mesoporous Y-type molecular sieve has good hydrothermal stability, and the uniform mesoporous structure allows macromolecular reactants to contact the active centers inside the molecular sieve. From the patents and literature that have been reported so far, it is difficult to directly synthesize high-silicon mesoporous Y-type molecular sieve without adding a template agent. Therefore, it is urgent to explore a preparation method for high-silicon mesoporous Y-type molecular sieve. Summary of the invention

[0008] The object of the present invention is to provide a method for preparing a high-silicon mesoporous Y-type molecular sieve, which is to use a common NaY molecular sieve with Si / Al≤2.8 as a raw material, first pre-treat it, remove some silicon and aluminum atoms from the molecular sieve framework, and introduce structural defects into the molecular sieve framework. The pre-treatment described herein is a combination of one or more methods of alkali treatment, acid treatment, and treatment, wherein acid treatment or a combination of acid treatment and alkali treatment is preferred, and fluorine treatment is more preferred. The pre-treated molecular sieve is then mixed evenly with a silicon-containing alkaline solution, and then sealed and treated for a certain period of time under certain temperature conditions. The molecular sieve obtained by the above treatment has significantly improved crystallinity and micropore volume compared with the molecular sieve obtained after pretreatment, and has significantly improved mesopore volume and silicon-aluminum ratio compared with the original NaY molecular sieve.

[0009] One of the purposes of the present invention is to provide a method for preparing a high-silicon mesoporous Y-type molecular sieve, and the second purpose is to provide a highly crystalline high-silicon mesoporous Y-type molecular sieve.

[0010] In one aspect of the present invention, a method for preparing a high-silicon mesoporous Y-type molecular sieve is disclosed, comprising the following steps:

[0011] (1) mixing a low-silicon Y-type molecular sieve with an aqueous solution of a pretreatment agent, and treating the obtained mixture at 0-50° C. for 1-24 h to obtain a mixture A;

[0012] (2) washing the obtained mixture A in deionized water until the pH of the washing solution is neutral, and drying at 100-200° C. for 12-24 h to obtain a powdered molecular sieve B;

[0013] (3) performing ion exchange on the obtained powdered molecular sieve B in a sodium salt solution at 20-100° C. for 12-48 hours to obtain a mixture C;

[0014] (4) washing the obtained mixture C in deionized water until the pH of the washing solution is neutral, and drying at 80-200° C. for 12-24 h to obtain a powdered molecular sieve D;

[0015] (5) preparing a regrowing mother liquor, mixing the powdered molecular sieve D obtained in step (4) with the mother liquor and transferring the mixture into a crystallization kettle, crystallizing the mixture at 80-180° C. for 0-24 h, taking the mixture out, washing, filtering and drying the mixture to obtain a high-silicon mesoporous Y-type molecular sieve.

[0016] The pretreatment agent in step (1) is one or more of an acid, a base, or an alkali metal or ammonium fluoride, preferably an acid, an acid and a base, or an alkali metal fluoride, and more preferably an alkali metal or ammonium fluoride; wherein the mass ratio of the low silicon molecular sieve (dry basis), the pretreatment agent and water is (0.1-1): (0.01-1): (1-100), preferably (0.3-0.5): (0.05-0.2): (20-50); the silicon to aluminum ratio of the low silicon Y-type molecular sieve is 1.5-2.8.

[0017] The sodium salt solution for ion exchange in step (3) is one or more of sodium chloride solution, sodium sulfate solution and sodium nitrate solution; preferably sodium nitrate solution or sodium sulfate solution.

[0018] The concentration of the sodium salt solution for ion exchange in step (3) is 1-10wt%, preferably 2-5wt%.

[0019] After the washing process in step (4) is completed, the reaction system is dried at 80-120°C, preferably 80-100°C.

[0020] The crystallization kettle in step (5) is a self-pressurized polytetrafluoroethylene-lined stainless steel pressure-resistant reactor; the re-growth mother liquor comprises a silicon source, an alkali, a salt and water, wherein the silicon source is calculated as SiO2, the alkali is calculated as NaO2, and the composition of the re-growth mother liquor is a molar ratio of SiO2:Na2O:salt:H2O=1-10:0.1-1:0.1-1:20-100, preferably SiO2:Na2O:salt:H2O=1-5:0.2-0.8:0.3-0.8:40-80; the salt is sodium sulfate.

[0021] The crystallization treatment temperature in step (5) is 80-180° C.; the crystallization treatment time is 1-24 hours.

[0022] Preferably, after the crystallization treatment in step (5) is completed, the temperature of the reaction system is lowered to room temperature, the crystallized product is filtered to obtain a solid and a mother liquor, the solid is washed with deionized water until the pH value is close to 7, and then dried at 100-120°C.

[0023] Another aspect of the present invention discloses a high-silicon mesoporous Y-type molecular sieve prepared by the above method, wherein the high-silicon mesoporous Y-type molecular sieve is highly crystallized and has intracrystalline mesopores, wherein the mesopore volume of the molecular sieve can reach 0.19 mL / g, and the microporous characteristics are retained, and the micropore volume is retained from 0.35 mL / g of the original molecular sieve to 0.32 mL / g; the Si / Al of the high-silicon mesoporous Y-type molecular sieve is ≥3, and more preferably 3-10.

[0024] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0025] The present invention is based on an in-depth understanding of the molecular sieve structure, framework hydrolysis and molecular sieve regeneration in the mother liquor process. It not only has basic scientific research value, but also has broad industrial application prospects. This work will also be a beneficial contribution and supplement to the research system of synthesizing high-silicon mesoporous Y-type molecular sieves.

[0026] The present invention uses common NaY molecular sieve with Si / Al≤2.8 as raw material, first performs certain pretreatment on it, removes part of silicon and aluminum atoms from the molecular sieve framework, and introduces structural defects in the molecular sieve framework. Then, the pretreated molecular sieve is evenly mixed with a silicon-containing alkaline solution, and then sealed for a certain time under certain temperature conditions. Compared with the original NaY molecular sieve, the molecular sieve obtained by the above treatment has significantly improved mesopore volume and silicon-aluminum ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the XRD spectra of the industrial NaY molecular sieve, the pretreated molecular sieve and the regenerated molecular sieve of Example 1 of the present invention;

[0028] Figure 2 is the XRD spectra of the industrial NaY molecular sieve, the pretreated molecular sieve and the regenerated molecular sieve of Example 2 of the present invention;

[0029] Figure 3 is a scanning electron microscope image of the ReNaY-F35-60 molecular sieve obtained in Example 2 of the present invention;

[0030] Figure 4 is a transmission electron microscope image of the ReNaY-F35-60 molecular sieve obtained in Example 2 of the present invention;

[0031] Figure 5 is the XRD spectra of the industrial NaY molecular sieve, the pretreated molecular sieve and the regenerated molecular sieve of Example 3 of the present invention;

[0032] Figure 6 is a scanning electron microscope image of the ReNaY-F35-120 molecular sieve obtained in Example 3 of the present invention;

[0033] Figure 7 is a transmission electron microscope image of the ReNaY-F35-120 molecular sieve obtained in Example 3 of the present invention;

[0034] Figure 8 is a physical adsorption diagram of the molecular sieve obtained in Example 2-3 of the present invention and the NaY molecular sieve;

[0035] Fig. 9 is the XRD spectra of the industrial NaY molecular sieve of Example 4 of the present invention, the pretreated molecular sieve and the regenerated molecular sieve;

[0036] Fig.10 is a scanning electron microscope image of the ReNaY-F40-60 molecular sieve obtained in Example 4 of the present invention;

[0037] Fig.11 is a transmission electron microscope image of the ReNaY-F40-60 molecular sieve obtained in Example 4 of the present invention;

[0038] Fig.12 is the XRD spectra of the industrial NaY molecular sieve, the pretreated molecular sieve and the regenerated molecular sieve of Example 5 of the present invention;

[0039] Fig.13 is a scanning electron microscope image of the ReNaY-F40-120 molecular sieve obtained in Example 5 of the present invention;

[0040] Fig.14 is a transmission electron microscope image of the ReNaY-F40-120 molecular sieve obtained in Example 5 of the present invention;

[0041] Fig.15 is a physical adsorption diagram of the molecular sieve obtained in Example 4-5 of the present invention and the NaY molecular sieve;

[0042] Fig.16 is the XRD spectra of the pretreated molecular sieve and the regrown molecular sieve of Comparative Examples 1-2 of the present invention; DETAILED DESCRIPTION

[0043] The following examples are used to further illustrate the present invention, but are not intended to limit the present invention.

[0044] Example 1

[0045] Weigh 6g of 25wt% ammonium fluoride solution and 1g of Y-type molecular sieve (sample name is NaY) respectively. Mix 6g of 25wt% ammonium fluoride solution and 1g of Y-type molecular sieve evenly at room temperature, react for 120 minutes under mechanical stirring, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain fluorine-treated molecular sieve (sample name is Y-F25-120). Weigh 1g of fluorine-treated molecular sieve, and exchange with 100g of 10wt% sodium sulfate solution at room temperature for 24h. After the end, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain the sodium-type fluorine-treated molecular sieve (sample name is NaY-F25-120). Weigh 20g of the mother liquor and 1g of the above molecular sieve respectively and transfer them into a 50ml polytetrafluoroethylene-lined stainless steel pressure-resistant reactor. Then place the sealed reactor in a 100°C oven for crystallization for 24 hours to obtain a high-silicon mesoporous Y-type molecular sieve (the sample name is ReNaY-F25-120).

[0046] Example 2

[0047] Weigh 6g of 35wt% ammonium fluoride solution and 1g of Y-type molecular sieve (sample name is NaY) respectively. Mix 6g of 35wt% ammonium fluoride solution and 1g of Y-type molecular sieve at room temperature, react for 3 minutes under ultrasound, ice water bath and mechanical stirring, filter and react with 6g of 25wt% ammonium fluoride solution under mechanical stirring for 60 minutes, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain fluorine-treated molecular sieve (sample name is Y-F35-60). Weigh 1g of fluorine-treated molecular sieve, ion exchange with 100g of 10wt% sodium sulfate solution at room temperature for 24h, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain sodium-type fluorine-treated molecular sieve (sample name is NaY-F35-60). Weigh 20g of the mother liquid and 1g of the above molecular sieve respectively and transfer them into a 50ml polytetrafluoroethylene-lined stainless steel pressure-resistant reactor, then place the sealed reactor in a 100°C oven for crystallization for 24 hours to obtain a high-silicon mesoporous Y-type molecular sieve (sample name is ReNaY-F35-60). The XRD pattern, scanning electron microscopy pattern, transmission electron microscopy pattern, and physical adsorption curve of the sample are shown in the figure below. Figure 1 , Figure 2 , Figure 3 , Figure 6 shown.

[0048] Example 3

[0049] Weigh 6g of 35wt% ammonium fluoride solution and 1g of Y-type molecular sieve (sample name is NaY) respectively. Mix 6g of 35wt% ammonium fluoride solution and 1g of Y-type molecular sieve at room temperature, react for 3 minutes under ultrasound, ice water bath and mechanical stirring, filter and react with 6g of 25wt% ammonium fluoride solution under mechanical stirring for 120 minutes, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain fluorine-treated molecular sieve (sample name is Y-F35-120). Weigh 1g of fluorine-treated molecular sieve, ion exchange with 100g of 10wt% sodium sulfate solution at room temperature for 24h, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain sodium-type fluorine-treated molecular sieve (sample name is NaY-F35-120). Weigh 20g of the mother liquid and 1g of the above molecular sieve respectively and transfer them into a 50ml polytetrafluoroethylene-lined stainless steel pressure-resistant reactor, then place the sealed reactor in a 100°C oven for crystallization for 24 hours to obtain a high-silicon mesoporous Y-type molecular sieve (sample name is ReNaY-F35-120). The XRD pattern, scanning electron microscopy pattern, transmission electron microscopy pattern, and physical adsorption curve of the sample are shown in the figure below. Figure 1 , Figure 4 , Figure 5 , Figure 6 shown.

[0050] Example 4

[0051] Weigh 6g of 40wt% ammonium fluoride solution and 1g of Y-type molecular sieve (sample name is NaY) respectively. Mix 6g of 40wt% ammonium fluoride solution and 1g of Y-type molecular sieve at room temperature, react for 5 minutes under ultrasound, ice water bath and mechanical stirring, filter and react with 6g of 25wt% ammonium fluoride solution under mechanical stirring for 60 minutes, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain fluorine-treated molecular sieve (sample name is Y-F40-60). Weigh 1g of fluorine-treated molecular sieve, ion exchange with 100g of 10wt% sodium sulfate solution at room temperature for 24h, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain sodium-type fluorine-treated molecular sieve (sample name is NaY-F40-60). Weigh 20g of the mother liquid and 1g of the above molecular sieve respectively and transfer them into a 50ml polytetrafluoroethylene-lined stainless steel pressure-resistant reactor, then place the sealed reactor in a 100°C oven for crystallization for 24 hours, and obtain a high-silicon mesoporous Y-type molecular sieve (sample name is ReNaY-F40-60). The XRD pattern, scanning electron microscopy pattern, transmission electron microscopy pattern, and physical adsorption curve of the sample are shown in the figure below. Figure 7 , Figure 8 , Fig. 9 , Fig.12 shown.

[0052] Example 5

[0053] Weigh 6g of 40wt% ammonium fluoride solution and 1g of Y-type molecular sieve (sample name is NaY) respectively. Mix 6g of 40wt% ammonium fluoride solution and 1g of Y-type molecular sieve at room temperature, react for 5 minutes under ultrasound, ice water bath and mechanical stirring, filter and react with 6g of 25wt% ammonium fluoride solution under mechanical stirring for 120 minutes, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain fluorine-treated molecular sieve (sample name is Y-F45-120). Weigh 1g of fluorine-treated molecular sieve, ion exchange with 100g of 10wt% sodium sulfate solution at room temperature for 24h, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain sodium-type fluorine-treated molecular sieve (sample name is NaY-F40-120). Weigh 20g of the mother liquid and 1g of the above molecular sieve respectively and transfer them into a 50ml polytetrafluoroethylene-lined stainless steel pressure-resistant reactor, then place the sealed reactor in a 100°C oven for crystallization for 24 hours to obtain a high-silicon mesoporous Y-type molecular sieve (sample name is ReNaY-F40-120). The XRD pattern, scanning electron microscopy pattern, transmission electron microscopy pattern, and physical adsorption curve of the sample are shown in Figure 1. Figure 7 , Fig.10 , Fig.11 , Fig.12 shown.

[0054] Comparative Example 1

[0055] Weigh 6g of 45wt% ammonium fluoride solution and 1g of Y-type molecular sieve (sample name is NaY) respectively. Mix 6g of 45wt% ammonium fluoride solution and 1g of Y-type molecular sieve at room temperature, react for 5 minutes under ultrasound, ice water bath and mechanical stirring, filter and react with 6g of 25wt% ammonium fluoride solution under mechanical stirring for 60 minutes, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain fluorine-treated molecular sieve (sample name is Y-F45-60). Weigh 1g of fluorine-treated molecular sieve, ion exchange with 100g of 10wt% sodium sulfate solution at room temperature for 24h, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain sodium-type fluorine-treated molecular sieve (sample name is NaY-F45-60). Weigh 20g of the mother liquid and 1g of the above molecular sieve respectively and transfer them into a 50ml polytetrafluoroethylene-lined stainless steel pressure-resistant reactor, then place the sealed reactor in a 100℃ oven for crystallization for 24 hours to obtain a high-silicon mesoporous Y-type molecular sieve (sample name is ReNaY-F45-60). The XRD pattern of the sample is shown in Fig.13 shown.

[0056] Comparative Example 2

[0057] Weigh 6g of 45wt% ammonium fluoride solution and 1g of Y-type molecular sieve (sample name is NaY) respectively. Mix 6g of 45wt% ammonium fluoride solution and 1g of Y-type molecular sieve at room temperature, react for 5 minutes under ultrasound, ice water bath and mechanical stirring, filter and react with 6g of 25wt% ammonium fluoride solution under mechanical stirring for 120 minutes, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain fluorine-treated molecular sieve (sample name is Y-F45-120). Weigh 1g of fluorine-treated molecular sieve, ion exchange with 100g of 10wt% sodium sulfate solution at room temperature for 24h, filter to deionized water and wash until the pH value is close to 7, and then dry at 100°C to obtain sodium-type fluorine-treated molecular sieve (sample name is NaY-F45-120). Weigh 20g of the mother liquid and 1g of the above molecular sieve respectively and transfer them into a 50ml polytetrafluoroethylene-lined stainless steel pressure-resistant reactor, then place the sealed reactor in a 100℃ oven for crystallization for 24 hours to obtain a high-silicon mesoporous Y-type molecular sieve (sample name is ReNaY-F45-120). The XRD pattern of the sample is shown in Fig.13 shown.

[0058] The above embodiments describe the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention, and are not intended to limit the scope of the present invention in any way. Without departing from the scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the protection claimed.

Claims

1. A method for preparing a high-silicon mesoporous Y-type molecular sieve, comprising the following steps: (1) mixing a low-silicon Y-type molecular sieve with an aqueous solution of a pretreatment agent, and treating the obtained mixture at 0-50° C. for 1-24 h to obtain a mixture A; (2) washing the obtained mixture A in deionized water until the pH of the washing solution is neutral, and drying at 100-200° C. for 12-24 h to obtain a powdered molecular sieve B; (3) performing ion exchange on the obtained powdered molecular sieve B in a sodium salt solution at 20-100° C. for 12-48 hours to obtain a mixture C; (4) washing the obtained mixture C in deionized water until the pH of the washing solution is neutral, and drying at 80-200° C. for 12-24 h to obtain a powdered molecular sieve D; (5) preparing a regrowing mother liquor, mixing the powdered molecular sieve D obtained in step (4) with the mother liquor and transferring the mixture into a crystallization kettle, crystallizing the mixture at 80-180° C. for 1-24 h, taking the mixture out, washing, filtering and drying the mixture to obtain a high-silicon mesoporous Y-type molecular sieve.

2. The method according to claim 1, characterized in that The pretreatment agent in step (1) is one or more of a base, an acid, and an alkali metal fluoride, preferably an acid, or an acid and a base, an alkali metal or ammonium fluoride, more preferably an alkali metal or ammonium fluoride.

3. The method according to claim 1, characterized in that In step (1), the mass ratio of low silicon Y-type molecular sieve (dry basis), pretreatment agent and water is (0.1-1): (0.01-1): (1-100), preferably NaY molecular sieve (0.3-0.5): pretreatment agent (0.05-0.2): H2O (20-50), and the silicon-aluminum ratio of the low silicon Y-type molecular sieve is 1.5-2.

8.

4. The method according to claim 1, characterized in that The sodium salt solution for ion exchange in step (3) is one or more of sodium chloride solution, sodium sulfate solution and sodium nitrate solution; preferably sodium nitrate solution or sodium sulfate solution.

5. The method according to claim 1, characterized in that The concentration of the sodium salt solution for ion exchange in step (3) is 1-10wt%, preferably 2-5wt%.

6. The method according to claim 1, characterized in that After the washing process in step (4) is completed, the reaction system is dried at 80-120°C, preferably 80-100°C.

7. The method according to claim 1, characterized in that The re-growth mother solution in step (5) comprises a silicon source, an alkali, a salt and water, wherein the silicon source is calculated as SiO2, the alkali is calculated as NaO2, and the composition of the re-growth mother solution is a molar ratio of SiO2:Na2O:salt:H2O=1-10:0.1-1:0.1-1:20-100, preferably SiO2:Na2O:salt:H2O=1-5:0.2-0.8:0.3-0.8:40-80; the salt is sodium sulfate.

8. The method according to claim 1, characterized in that The crystallization kettle in step (5) is a self-pressurized polytetrafluoroethylene-lined stainless steel pressure-resistant reactor; the crystallization treatment temperature in step (5) is 100-180° C.; and the crystallization treatment time is 2-12 hours.

9. The method according to claim 1, characterized in that After the crystallization treatment in step (5) is completed, the temperature of the reaction system is lowered to room temperature, and the crystallized product is filtered to obtain a solid and a mother liquor. The solid is washed with deionized water until the pH value is close to 7, and then dried at 100-120°C.

10. A high-silicon mesoporous Y-type molecular sieve containing mesopores prepared according to the method according to any one of claims 1 to 9, characterized in that The molecular sieve comprises the microporous structure of the Y-type molecular sieve itself and the uniformly distributed mesoporous structure generated by post-treatment; the silicon-aluminum ratio of the high-silicon mesoporous Y-type molecular sieve is 3-10.

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