Method for preparing modified voc adsorbents

Abstract

The application provides a preparation method of a modified VOCs adsorbent. S The modified VOCs adsorbent prepared by the application has excellent physical and chemical properties and environmental adaptability, is suitable for environmental protection applications in multiple fields, especially industrial emission and indoor air purification, and provides an efficient and environmentally-friendly technical solution for effectively controlling and reducing VOCs pollution.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis, and more specifically, to a method for preparing a modified VOCs adsorbent. Background Technology

[0002] Molecular sieves are aluminosilicates characterized by uniform pore size, regular crystal structure, abundant pore system, large specific surface area, and good thermal stability. They are considered preferred adsorbent materials for removing oxygen-containing compounds from olefins. FAU-type (X and Y-type) molecular sieves have a pore size of approximately 0.74 nm. X-type molecular sieves, in particular, are well-researched for removing oxygen-containing compound impurities from olefins and have been applied in industrial practice.

[0003] First, the uniform and ordered microporous structure of 13X molecular sieves enables precise molecular sieving. The size and shape of the micropores allow for highly specific adsorption of molecules of specific sizes and shapes, while excluding other molecules, which is invaluable in separation and purification processes in the chemical industry. For example, in gas separation, 13X molecular sieves can effectively separate target gases such as oxygen, nitrogen, or carbon dioxide from mixed gas streams. Second, the large specific surface area provides more active adsorption sites, increasing the adsorption capacity of 13X molecular sieves. This means that within the same physical volume, 13X molecular sieves can adsorb more substances, thereby improving processing rates and efficiency. This characteristic is particularly important in areas such as liquid or gas purification, catalyst supports, and storage media.

[0004] Therefore, the properties of 13X molecular sieves, including uniform and ordered micropores, large specific surface area, and large pore capacity, not only demonstrate enormous potential in traditional chemical, oil and gas processing fields, but also show broad application prospects in emerging fields such as environmental protection, clean energy, and life sciences. For example, in industrial waste gas treatment, 13X molecular sieves can effectively remove harmful gases and volatile organic compounds (VOCs); in pharmaceutical and fine chemical production, they can be used to improve product purity and yield.

[0005] With increasing industrialization, VOC emissions in the air are constantly rising, posing a serious threat to human health and the environment. Commonly used VOC removal technologies include adsorption and catalytic combustion. Among these, adsorption is widely used due to its simplicity and low cost. 13X molecular sieves, with their good thermal stability and large pore size, have become the preferred adsorbent for VOC removal. However, there is still room for improvement in the adsorption efficiency of traditional 13X molecular sieves for certain VOCs. Therefore, finding a VOC adsorbent with high adsorption efficiency is key to solving the current problem of excessively high VOC emissions. Summary of the Invention

[0006] The main objective of this invention is to provide a method for preparing a modified VOCs adsorbent, so as to solve the problem of low adsorption efficiency of VOCs adsorbents in the prior art.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a modified VOCs adsorbent is provided, the method comprising: introducing cerium ions into a carbon-modified 13X molecular sieve to obtain a cerium ion-containing molecular sieve; subjecting the cerium ion-containing molecular sieve to alkali treatment and a first calcination in sequence to obtain an adsorbent precursor; and introducing siloxane groups into the adsorbent precursor to obtain the modified VOCs adsorbent.

[0008] Further, the above preparation method includes: immersing the carbon-modified 13X molecular sieve in a cerium nitrate solution for ion exchange to obtain the cerium-containing molecular sieve; immersing the cerium-containing molecular sieve in an alkaline solution and then performing the first calcination to obtain the adsorbent precursor; immersing the adsorbent precursor in a mixture of silane and alcohol to introduce the siloxane group to obtain the modified VOCs adsorbent.

[0009] Further, the cerium-containing ion solution is selected from any one or more of the following: cerium chloride, cerium nitrate, cerium citrate, or cerium acetate; preferably, the molar concentration of the cerium ion solution is 0.05–0.5 mol / L; preferably, the mass ratio of the carbon-modified 13X molecular sieve to the volume ratio of the cerium ion solution is 1–20:100 g / mL; preferably, the ion exchange time is 22–26 h; preferably, the carbon-modified 13X molecular sieve needs to undergo a first drying after the ion exchange; more preferably, the temperature of the first drying is 100–120 °C, and the time is 10–14 h.

[0010] Further, the molar concentration of the above-mentioned alkaline solution is 2 to 2.5 mol / L; preferably, the above-mentioned alkaline solution is selected from any one or more of the following: NaOH solution, KOH or ammonia solution; preferably, the above-mentioned cerium ion-containing molecular sieve is immersed in the above-mentioned alkaline solution for 1 to 3 hours and then subjected to the above-mentioned first calcination, preferably the temperature of the above-mentioned first calcination is 400 to 600°C and the time is 4 to 8 hours, to obtain the above-mentioned adsorbent precursor.

[0011] Further, the silane is selected from any one or more of the following: ethyltriethoxysilane, methyltrimethoxysilane, or propenyltrimethoxysilane; the alcohol is selected from any one or more of the following: ethanol, propanol, or butanol; preferably, the ethyltriethoxysilane and the ethanol are mixed in a volume ratio of 1:8 to 1:10 to form the mixture; preferably, the adsorbent precursor is immersed in the mixture for 12 to 24 hours; preferably, after the adsorbent precursor is immersed in the mixture and before the modified VOCs adsorbent is obtained, the preparation method further includes the steps of drying and second calcining the adsorbent precursor after immersion in the mixture, wherein the second calcination temperature is 500 to 700°C and the time is 2 to 4 hours.

[0012] Furthermore, the preparation method of the above-mentioned carbon-modified 13X molecular sieve includes:

[0013] Step S1: Mix the aluminum source and silicon source with water respectively to obtain aluminum-containing materials and silicon-containing materials;

[0014] Step S2: Mix the above aluminum-containing material and the above silicon-containing material, and then stir, adjust the pH value and crystallize in sequence to obtain the crystallized product;

[0015] Step S3: The material containing molecular sieves is subjected to aluminum and silicon dissolution treatment to obtain aluminum-rich liquid and silicon-rich liquid, and the two are mixed to obtain gel-like mother liquor;

[0016] Step S4: The crystallized product from step S2 and the gel-like mother liquor from step S3 are mixed, aged, hydrothermally crystallized, filtered, washed and dried, then immersed in a carbon precursor solution, calcined and shaped under an inert gas atmosphere to obtain the above-mentioned 13X molecular sieve.

[0017] Furthermore, the aluminum source mentioned above is selected from any one or more of the following: sodium aluminate, boehmite, aluminum sulfate, or aluminum nitrate.

[0018] Furthermore, the silicon source mentioned above is selected from any one or more of the following: silica sol, tetraethyl orthosilicate, coarse-porous silica gel, silica powder, fly ash, or silica.

[0019] Furthermore, the conditions for mixing the silicon source and the water are as follows: stirring at 20–60°C for 0.1–12 h, maintaining a stirring speed of 200–800 rpm; and the concentration of the silicon-containing material is 28–99 wt%.

[0020] Furthermore, the mixing conditions for the aluminum source and the water are: stirring at 20–60°C for 0.1–12 h, with a preferred stirring speed of 200–800 rpm; and the concentration of the aluminum-containing material is 15–99 wt%.

[0021] Furthermore, the stirring conditions in step S2 are stirring at 20–100°C for 0.1–24 hours.

[0022] Furthermore, the above crystallization is a two-stage crystallization, wherein the first stage crystallization temperature is 20-60℃ and the crystallization time is 4-24h; the second stage crystallization temperature is 80-120℃ and the crystallization time is 6-48h; the above crystallization is carried out in a hydrothermal reactor; preferably, the second stage crystallization temperature is higher than the first stage crystallization temperature, and the difference is ≥40℃.

[0023] Furthermore, the molar ratios of the components in the above-mentioned crystallized products are SiO2 / Al2O3 = 0.01–2.5:1, Na2O / SiO2 = 0.01–4.0:1, and H2O / SiO2 = 1.0–40.0:1.

[0024] Furthermore, the aforementioned molecular sieve-containing materials are selected from any one or more of the following: waste ZSM-5 molecular sieve catalyst, waste MTO catalyst, waste molecular sieve adsorbent, fly ash, waste FCC catalyst, or waste VOCs adsorbent.

[0025] Furthermore, the above-mentioned steps of dissolving aluminum and dissolving silicon are as follows:

[0026] (1) The above-mentioned molecular sieve material with a mesh size of less than 200 after grinding is mixed with Na2CO3 at a mass ratio of 1:0.5 to 1:5. After being calcined at 550 to 800°C for 60 to 120 minutes, it is dissolved in a monobasic acid with a mass fraction of 10% to 35%. After filtration, the above-mentioned aluminum-rich liquid is obtained.

[0027] (2) The residue filtered in (1) above is mixed with NaOH:H2O at a mass ratio of 0~100:40~60:50~400, stirred and filtered evenly to obtain the above silicon-rich liquid.

[0028] Furthermore, the molar ratios of the components in the above-mentioned gel-like mother liquor are: SiO2 / Al2O3 = 0.5–6.0:1, Na2O / SiO2 = 0.5–6.0:1, and H2O / SiO2 = 10–100:1.

[0029] Furthermore, the amount of the crystallized product added accounts for 5 to 20 wt% of the gel-like mother liquor.

[0030] Furthermore, the aging conditions are as follows: aging temperature is 20–100℃, aging time is 0.1–24 h, and the aging process is carried out under stirring conditions.

[0031] Furthermore, the carbon precursor solution described above is selected from any one or more of the following: benzene, furan, or furfural.

[0032] The present invention utilizes a modified VOCs adsorbent prepared by introducing cerium ions (Ce) and siloxane groups into carbon-modified 13X molecular sieves, which possess numerous adsorption sites, large pore volume, and good selectivity. This process overcomes the low adsorption efficiency of existing VOCs adsorbents. The carbon-modified 13X molecular sieve exhibits a high silicon-to-aluminum ratio, high silicon source utilization, and good selectivity, which can be adjusted according to different adsorbed molecules, thereby significantly reducing the carbon deposition rate of the molecular sieve and improving the diffusion performance of the adsorbent. The introduction of cerium ions (Ce) effectively increases the specific surface area and pore volume of the molecular sieve, significantly improving the adsorption capacity of the adsorbent for VOCs. The introduction of cerium ions also promotes the formation of more active sites, further enhancing the adsorption performance. The introduction of siloxane groups helps increase the lifespan of the adsorbent. Therefore, the VOCs adsorbent prepared by this invention... S The adsorbent can adsorb various VOCs, including ethylene, formaldehyde, and benzene. S Adsorbents possess excellent physicochemical properties and environmental adaptability, making them suitable for environmental protection applications in various fields, especially industrial emissions and indoor air purification. They provide an efficient and environmentally friendly technical solution for effectively controlling and reducing VOCs pollution. Detailed Implementation

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this invention can be combined with each other. The invention will now be described in detail with reference to the embodiments.

[0034] As mentioned in the background section, VOC emissions in the air are constantly increasing, and excessive VOCs pose a significant threat to the environment. However, existing VOC adsorbents suffer from low adsorption efficiency, making improving the adsorption efficiency of VOC adsorbents crucial for solving this problem. Carbon-modified 13X molecular sieves possess advantages such as numerous adsorption sites, large pore volume, and good selectivity, making them ideal materials for preparing high-efficiency VOC adsorbents. Therefore, in this invention, the inventors attempted to introduce cerium ions and siloxane groups into carbon-modified 13X molecular sieves, significantly increasing the adsorption capacity of the VOC adsorbent and further enhancing its adsorption performance. Based on this, a series of protective schemes of this invention are proposed.

[0035] In a typical embodiment of the present invention, a method for preparing a modified VOCs adsorbent is provided, the method comprising: introducing cerium ions into a carbon-modified 13X molecular sieve to obtain a cerium ion-containing molecular sieve; subjecting the cerium ion-containing molecular sieve to alkali treatment and a first calcination in sequence to obtain an adsorbent precursor; and introducing siloxane groups into the adsorbent precursor to obtain the modified VOCs adsorbent.

[0036] The aforementioned carbon-modified 13X molecular sieve provides more adsorption sites, introduces mesoporous channels, increases the pore volume inside the molecular sieve crystal, and improves the diffusion performance of guest molecules within the molecular sieve. It also exhibits a uniform morphology, resulting in well-defined nanoparticles. Furthermore, the carbon-modified 13X molecular sieve of this invention has a high silicon-to-aluminum ratio, high silicon source utilization, and good selectivity. It can be controlled according to different adsorbed molecules, thereby significantly reducing the carbon deposition rate of the molecular sieve and improving the diffusion performance of the adsorbent. This makes it an excellent material for preparing VOCs adsorbents.

[0037] The introduction of cerium ions (Ce) not only effectively increases the specific surface area and pore volume of the molecular sieve, significantly improving the adsorption capacity of the adsorbent for VOCs, but also promotes the formation of more active sites on the molecular sieve, thereby effectively enhancing the adsorption of VOCs. The introduction of siloxane groups helps to increase the service life of the molecular sieve.

[0038] The specific methods for introducing the cerium ions and siloxane groups are not limited, including but not limited to immersing the carbon-modified 13X molecular sieve in solutions containing cerium ions and silanol solutions, respectively, thereby introducing cerium ions and siloxane groups. The specific methods can be optimized or improved based on existing methods.

[0039] In a preferred embodiment of the present invention, the carbon-modified 13X molecular sieve is immersed in a cerium nitrate solution for ion exchange to obtain the cerium-containing molecular sieve; the cerium-containing molecular sieve is then immersed in an alkaline solution and subjected to the first calcination to obtain the adsorbent precursor; the adsorbent precursor is then immersed in a mixture of silane and alcohol to introduce the siloxane groups to obtain the modified VOCs adsorbent. In the preferred embodiment, by introducing cerium ions and siloxane groups in the above manner, the adsorption performance and stability of the obtained VOCs adsorbent can be significantly improved.

[0040] Depending on the application scenario of the VOCs adsorbent, the requirements for adsorption performance vary, and consequently, the specific parameters and conditions of each step also differ. In a preferred embodiment of the present invention, the cerium ion-containing solution is a cerium nitrate solution, and the molar concentration of the cerium ion solution is 0.05–0.5 mol / L. Preferably, the mass ratio of the carbon-modified 13X molecular sieve to the volume ratio of the cerium ion solution is 1–20:100 g / mL, which has the beneficial effect of rapidly achieving ion exchange. Preferably, the ion exchange time is 22–26 h. Preferably, the carbon-modified 13X molecular sieve needs to undergo a first drying after the ion exchange. More preferably, the temperature of the first drying is 100–120 °C, and the time is 10–14 h. The purpose of drying is to fully fix the cerium ions in the molecular sieve channels.

[0041] Excessive cerium nitrate concentration leads to rapid deposition of cerium ions within the molecular sieve channels, affecting channel flow and reducing adsorption efficiency. Ion exchange reactions conducted in a cerium ion solution improve efficiency, introduce more adsorption sites, and optimize pore structure. The molar concentration of the aforementioned alkaline solution is 2–2.5 mol / L.

[0042] The alkaline solution of this invention is a NaOH solution, KOH, or an ammonia solution. Preferably, the above-mentioned cerium-containing molecular sieve is immersed in the alkaline solution for 1 to 3 hours. The purpose of the alkaline treatment is to remove impurities that may be introduced during the ion exchange process and to effectively improve the stability of the molecular sieve.

[0043] After alkali treatment, the above-mentioned first calcination is performed, preferably at a temperature of 400–600°C for 4–8 hours, to obtain the above-mentioned adsorbent precursor. Calcination after alkali treatment can remove moisture or organic matter introduced during the treatment process, which is beneficial for subsequent silanization treatment, thereby effectively improving structural stability.

[0044] The silanes mentioned above are selected from any one or more of the following: ethyltriethoxysilane, methyltrimethoxysilane, or propenyltrimethoxysilane; the alcohols mentioned above are selected from any one or more of the following: ethanol, propanol, or butanol. In the above mixture, the volume ratio of silane to alcohol can be adjusted appropriately according to actual needs.

[0045] In a preferred embodiment of this application, ethyltriethoxysilane and ethanol are mixed in a volume ratio of 1:8 to 1:10 to form the above-mentioned mixture. In this mixture, ethyltriethoxysilane has good affinity with carbon-modified 13X molecular sieves, which helps the carbon-modified 13X molecular sieves form a complete and highly effective protective layer. Ethanol assists in better dispersing the carbon-modified 13X molecular sieves in the mixture, increasing the contact area between ethyltriethoxysilane and the carbon-modified 13X molecular sieves, thus contributing to the formation of the protective layer.

[0046] Preferably, the adsorbent precursor is immersed in the mixture for 12–24 hours. A suitable immersion time helps to ensure more complete silanization of the carbon-modified 13X molecular sieve. Preferably, after immersing the adsorbent precursor in the mixture and before obtaining the modified VOCs adsorbent, the preparation method further includes drying and a second calcination of the adsorbent precursor after immersion in the mixture. The second calcination temperature is 500–700°C, and the time is 2–4 hours. Calcination after silanization facilitates the effective formation of a coating by the adsorbed siloxane groups during silanization, providing a stable protective layer for the high-pore-capacity molecular sieve containing active sites, thereby improving its stability in use.

[0047] The preparation of the above-mentioned adsorbent requires carbon-modified 13X molecular sieve as raw material. The preparation method of the carbon-modified 13X molecular sieve is not specifically limited; different methods for preparing the carbon-modified 13X molecular sieve can be selected according to actual needs. In a preferred embodiment of this application, the preparation method of the above-mentioned carbon-modified 13X molecular sieve includes:

[0048] Step S1: The aluminum source and silicon source are mixed with water separately to obtain aluminum-containing materials and silicon-containing materials. The silicon source is selected from one or more of silica sol, tetraethyl orthosilicate, coarse-porous silica gel, silica powder, fly ash, and silica. The mixing process of the silicon source and water is generally carried out at 20-60°C for 0.1-12 hours with a stirring speed maintained at 200-800 rpm to obtain silicon-containing materials with a concentration of 28-99 wt%. The aluminum source is selected from one or more of sodium aluminate, boehmite, aluminum sulfate, and aluminum nitrate.

[0049] The mixing process of aluminum source and water is generally carried out at 20-60℃ for 0.1-12 hours, with the stirring speed maintained at 200-800 rpm, to obtain aluminum-containing material with a concentration of 15-99 wt%. Suitable stirring temperature, duration and speed can ensure better dissolution of aluminum and silicon sources. The silicon-containing material and aluminum-containing material at the above concentrations have good compatibility, which helps to make subsequent mixing more uniform and the reaction more complete.

[0050] Step S2: Mix the above-mentioned aluminum-containing material and silicon-containing material, and sequentially stir, adjust the pH value, and perform crystallization treatment to obtain a crystallized product. Stir the above-mentioned aluminum-containing material and silicon-containing material at 20-100℃ for 0.1-24h, and after uniform mixing, obtain a mixture gel composed of aluminum source and silicon source, which is used to prepare for the subsequent preparation of molecular sieves.

[0051] The aforementioned mixture gel also needs pH adjustment. The adjusted pH should be 8.5–12.5, which is alkaline. An alkaline environment facilitates better mixing and reaction of the silicon and aluminum sources, thereby increasing the silicon-to-aluminum ratio, specific surface area, and pore capacity of the molecular sieve. The method of pH adjustment is not specifically limited; a solid alkali or an aqueous solution of alkali can be slowly added to the mixture gel.

[0052] Furthermore, the aforementioned mixture gel requires crystallization treatment, which is divided into two stages. The first stage crystallization occurs at a temperature of 20–60°C for 4–24 hours, resulting in a more complete and uniform crystal structure for the molecular sieve. The second stage crystallization occurs at a temperature of 80–120°C for 6–48 hours, further enhancing the integrity and uniformity of the molecular sieve crystal structure. Extensive experimental verification by the inventors revealed that when the temperature of the second stage crystallization is 40°C higher than that of the first stage, the molar ratio of the components in the crystallized product can be further optimized, thereby effectively improving adsorption capacity.

[0053] In a preferred embodiment of the present invention, the crystallization is preferably carried out in a hydrothermal reactor. The molar ratios of the components in the crystallized product are SiO2 / Al2O3 = 0.01–2.5:1, Na2O / SiO2 = 0.01–4.0:1, and H2O / SiO2 = 1.0–40.0:1. Limiting the molar ratios of the components helps to obtain a better pore structure, thereby better obtaining a VOCs adsorbent with excellent adsorption properties in subsequent preparation processes.

[0054] Step S3: The molecular sieve-containing material is subjected to aluminum and silicon dissolution treatments to obtain aluminum-rich liquid and silicon-rich liquid, which are then mixed to obtain a gel-like mother liquor. It should be noted that the molecular sieve-containing material is selected from any one or more of the following: spent ZSM-5 molecular sieve catalyst, spent MTO catalyst, spent molecular sieve adsorbent, fly ash, spent FCC catalyst, or spent VOCs adsorbent. Utilizing spent catalysts to prepare 13X molecular sieves solves the problem of wasted spent catalyst resources and reduces the production cost of 13X molecular sieves; the entire production process is economical and environmentally friendly.

[0055] The above-mentioned process of dissolving aluminum and silicon in molecular sieve materials can be appropriately modified according to actual needs. In a preferred embodiment of this application, the above-mentioned steps of dissolving aluminum and silicon are as follows: (1) The above-mentioned molecular sieve material with a mesh size of less than 200 mesh after grinding is mixed with Na2CO3 at a mass ratio of 1:0.5 to 1:5, calcined at 550 to 800°C for 60 to 120 minutes, and then dissolved in a monobasic acid with a mass fraction of 10% to 35%. After filtration, the above-mentioned aluminum-rich liquid is obtained; (2) The residue filtered in (1) above is mixed with NaOH:H2O at a mass ratio of 0 to 100:40 to 60:50 to 400, stirred and mixed evenly, and then filtered to obtain the above-mentioned silicon-rich liquid. The above-mentioned process of dissolving aluminum and silicon is simple to operate, and the filter residue for preparing aluminum-rich liquid can be directly used as raw material for the production of silicon-rich liquid, further reducing the production cost of molecular sieves.

[0056] Step S4: There are various ways to carbon modify molecular sieves. In a preferred embodiment of this application, the crystallization product from step S2 and the gel-like mother liquor from step S3 are mixed, aged, hydrothermally crystallized, filtered, washed and dried, and then impregnated in a carbon precursor solution (benzene, furan or furfural). The mixture is then calcined and shaped under an inert gas atmosphere (nitrogen, helium, neon or argon) to obtain the carbon-modified 13X molecular sieve.

[0057] The amount of the crystallized product added accounts for 5 to 20 wt% of the gel-like mother liquor. Limiting the amount of crystallized product added is to ensure that there is enough silicon-aluminum source in the gel-like mother liquor to participate in the crystallization reaction, while avoiding uneven reaction caused by excessive crystallized product, which would affect the distribution of active sites of the molecular sieve and the pore volume performance of the molecular sieve.

[0058] To further optimize the crystal form and enhance the stability of carbon-modified 13X molecular sieve, the mixture of crystallization product and gel-like mother liquor needs to be aged. The aging conditions are: aging temperature of 20-100℃, aging time of 0.1-24h, and the aging process is carried out under stirring conditions, which can make the crystal structure more uniform and the crystal size more uniform.

[0059] The hydrothermal crystallization temperature is 60–105℃, and the crystallization time is 0.1–36 h. This process promotes the growth of molecular sieve crystals, improves their crystal form, and enhances their thermal and mechanical stability. The reaction product is then filtered, washed until neutral, and dried at 80–120℃ until no significant weight loss is observed to obtain 13X molecular sieve.

[0060] The beneficial effects of the present invention will be explained in more detail below with reference to specific embodiments.

[0061] Example 1:

[0062] (1) Preparation method of 13X molecular sieve seed crystals

[0063] 21.0 g of silica sol (mass fraction 30%) was dissolved in 36.0 g of deionized water and pretreated in a sealed reactor at 25 °C and 500 rpm for 1 h to obtain a dispersed aqueous solution of silicon source.

[0064] 24g of aluminum sulfate was dissolved in 18.0g of deionized water and stirred at 25℃ and 500rpm for 1h to obtain an aqueous solution of aluminum source dispersion. The aqueous solution of aluminum source was slowly added dropwise to the aqueous solution of silicon source and stirred at 60℃ for 8h to obtain a gel solution.

[0065] Dissolve 6.74g of sodium hydroxide in 36g of deionized water dispersion and add it to the gel solution. Maintain the pH value at 12.0 to obtain the gel system.

[0066] The gel system was placed in a hydrothermal reactor and subjected to two-stage temperature-controlled crystallization. The first crystallization treatment was carried out at 40°C for 12 hours; the second crystallization treatment was carried out at 95°C for 24 hours, yielding a white liquid crystallized product.

[0067] In this crystallized product, the molar ratio of SiO2 to Al2O3 is 1.5:1, the molar ratio of Na2O to SiO2 is 1.6:1, and the molar ratio of H2O to SiO2 is 32:1.

[0068] (2) Preparation method of carbon-modified 13X molecular sieve

[0069] Introducing waste catalyst: 10g of 200-mesh waste ZSM-5 molecular sieve catalyst sample was mixed with 8g of 10% Na2CO3 and calcined at 650℃ for 120min to obtain the calcined product; the calcined product was dissolved in 25% nitric acid solution and filtered to obtain aluminum-rich liquid for later use.

[0070] 10g of the filtered residue, 6g of NaOH, and 40g of H2O were mixed evenly and then filtered to obtain a silica-rich solution. The silica-rich solution was then mixed with the aluminum-rich solution at a mass ratio of 1:4 to obtain a gel mother liquor. In this gel mother liquor, the molar ratio of SiO2 to Al2O3 was 3.5:1, the molar ratio of Na2O to SiO2 was 2.8:1, and the molar ratio of H2O to SiO2 was 80:1.

[0071] 25g of 13X molecular sieve seed crystals were added to the gel mother liquor and stirred and aged at 60℃ for 12h. The product was placed in a hydrothermal reaction for crystallization at 98℃ for 24h. The reaction product was filtered, washed, and adjusted to pH 7. It was then dried at 90℃ to obtain 13X molecular sieve.

[0072] Carbon modification: 13X molecular sieve was impregnated in 100 mL of a 10 wt% carbon precursor solution (carbon source: furan, solvent: tetrahydrofuran), with a mass ratio of 13X molecular sieve to carbon precursor solution of 2.5:1, and stirred for 24 h. Under a nitrogen atmosphere, the impregnated molecular sieve was heated to 800 °C for 2 h to obtain carbon-modified 13X molecular sieve.

[0073] (3) Modified VOCs S Methods for preparing adsorbents

[0074] Introducing cerium ions: Take 50g of carbon-modified 13X molecular sieve and dry it at 80℃ for 12h to remove residual moisture; immerse the dried carbon-modified 13X molecular sieve in 250mL of 0.2mol / L cerium nitrate (Ce(NO3)3) solution for 24h of ion exchange reaction; then dry the molecular sieve at 110℃ for 12h to obtain cerium-doped molecular sieve.

[0075] Cerium-doped molecular sieves were immersed in a 2 mol / L sodium hydroxide (NaOH) solution for 2 hours, and then calcined in air at 600°C for 4 hours to obtain expanded-pore molecular sieves.

[0076] The expanded-pore molecular sieve was immersed in a mixed solution containing 50 mL of ethyltriethoxysilane (TEOS) and 450 mL of ethanol for 12 h, dried again, and then calcined at 600 °C for 3 h to obtain the modified VOCs adsorbent.

[0077] Example 2:

[0078] (1) Preparation method of 13X molecular sieve seed crystals

[0079] Same as (1) in Example 1.

[0080] (2) Preparation method of carbon-modified 13X molecular sieve

[0081] Introducing waste catalyst: 12g of 200-mesh waste 13X adsorbent sample was mixed evenly with 10g of 15% Na₂CO₃ and calcined at 650℃ for 120min to obtain the calcined product. The calcined product was dissolved using a 15% nitric acid solution and filtered to obtain an aluminum-rich liquid for later use. 15g of the filtered residue, 6g of NaOH, and 40g of H₂O were mixed evenly and filtered to obtain a silicon-rich liquid. The aluminum-rich liquid and the silicon-rich liquid were mixed at a mass ratio of 1:3.5 to obtain a gel mother liquor. In this gel mother liquor, the molar ratio of SiO₂ to Al₂O₃ was 1.8:1, the molar ratio of Na₂O to SiO₂ was 4.5:1, and the molar ratio of H₂O to SiO₂ was 50:1.

[0082] 15g of the crystallized product was added to the gel mother liquor and stirred and aged at 60℃ for 12h. It was then placed in a hydrothermal reaction for crystallization at 95℃ for 24h. The reaction product was filtered, washed, and adjusted to pH 7. It was then dried at 90℃ to obtain 13X molecular sieve.

[0083] Carbon modification: 13X molecular sieve was impregnated in 100 mL of a 15 wt% carbon precursor solution (carbon source: benzene, solvent: methanol), with a mass ratio of 13X molecular sieve to carbon precursor solution of 3:1, and stirred for 24 h. Under a nitrogen atmosphere, the impregnated molecular sieve was heated to 750 °C for 3 h to obtain carbon-modified 13X molecular sieve.

[0084] (3) Modified VOCs S Methods for preparing adsorbents

[0085] Introducing cerium ions: Take 20g of carbon-modified 13X molecular sieve and dry it at 80℃ for 12h to remove residual moisture; immerse the dried carbon-modified 13X molecular sieve in 100mL of 0.5mol / L cerium nitrate (Ce(NO3)3) solution for 24h of ion exchange reaction; then dry the molecular sieve at 110℃ for 12h to obtain cerium-doped molecular sieve.

[0086] Cerium-doped molecular sieves were immersed in a 2.5 mol / L sodium hydroxide (NaOH) solution for 1 hour, and then calcined in air at 400 °C for 8 hours to obtain expanded-pore molecular sieves.

[0087] The expanded pore molecular sieve was immersed in a mixed solution containing 50 mL of trimethylsilane and 400 mL of methanol for 14 h, dried again, and then calcined at 500 °C for 4 h.

[0088] Example 3:

[0089] (1) Preparation method of 13X molecular sieve seed crystals

[0090] Same as (1) in Example 1.

[0091] (2) Preparation method of carbon-modified 13X molecular sieve

[0092] 5g of spent ZSM-5 molecular sieve catalyst and 6g of 200-mesh spent 13X adsorbent sample were mixed evenly with 15g of 15% Na2CO3 and calcined at 650℃ for 120min to obtain the calcined product. Then, the calcined product was dissolved and filtered with 15% nitric acid solution to obtain aluminum-rich liquid for later use.

[0093] 15g of the filtered residue, 8g of NaOH, and 45g of H2O were mixed evenly and filtered to obtain a silica-rich solution. An aluminum-rich solution with a mass ratio of 1:5.5 was then mixed with the silica-rich solution to obtain a gel mother liquor. In this gel mother liquor, the molar ratio of SiO2 to Al2O3 was 0.5:1, the molar ratio of Na2O to SiO2 was 6:1, and the molar ratio of H2O to SiO2 was 10:1.

[0094] 20g of the crystallized product was added to the gel mother liquor and stirred and aged at 60℃ for 12h. It was then placed in a hydrothermal reaction for crystallization treatment at 105℃ for 20h. The reaction product was filtered, washed, and adjusted to pH 7. It was then dried at 90℃ to obtain 13X molecular sieve.

[0095] Carbon modification: 13X molecular sieve was impregnated in 100 mL of an 8 wt% benzene solution (carbon source: benzene, solvent: ethanol), with a mass ratio of 13X molecular sieve to carbon precursor solution of 1:1, and stirred for 24 h. Under a nitrogen atmosphere, the impregnated molecular sieve was heated to 600 °C for 3.5 h.

[0096] (3) Preparation method of modified VOCs adsorbent

[0097] Introducing cerium ions: Take 10g of carbon-modified 13X molecular sieve and dry it at 80℃ for 12h to remove residual moisture; immerse the dried carbon-modified 13X molecular sieve in 1000mL of 0.05mol / L cerium nitrate (Ce(NO3)3) solution for 24h of ion exchange reaction; then dry the molecular sieve at 110℃ for 12h to obtain cerium-doped molecular sieve.

[0098] Cerium-doped molecular sieves were immersed in a 2.2 mol / L sodium hydroxide (NaOH) solution for 2 hours, and then calcined in air at 500°C for 6 hours to obtain expanded-pore molecular sieves.

[0099] The expanded-pore molecular sieve was immersed in a mixed solution containing 50 mL of triisopropylsilane and 500 mL of isopropanol for 10 h, dried again, and then calcined at 700 °C for 2 h to obtain a VOCs adsorbent.

[0100] Example 4:

[0101] (1) Preparation method of 13X molecular sieve seed crystals

[0102] Same as (1) in Example 1.

[0103] (2) Preparation method of carbon-modified 13X molecular sieve

[0104] The difference from Example 1 (2) is that when preparing the gel mother liquor, the aluminum-rich liquid and the silicon-rich liquid are mixed in a ratio of 1:2.5.

[0105] In this gel mother liquor, the molar ratio of SiO2 to Al2O3 is 6:1, the molar ratio of Na2O to SiO2 is 0.5:1, and the molar ratio of H2O to SiO2 is 100:1.

[0106] The added crystallized product was 30g added to the gel mother liquor and stirred and aged at 70℃ for 15h. It was then placed in a hydrothermal reaction for crystallization treatment at 115℃ for 16h. The reaction product was filtered, washed, and adjusted to pH 7. It was then dried at 90℃ to obtain 13X molecular sieve.

[0107] 13X molecular sieves were impregnated in 100 mL of a 20 wt% carbon precursor solution (carbon source: furfural, solvent: N,N-dimethylformamide), with a mass ratio of 13X molecular sieves to carbon precursor solution of 5:1, and stirred for 24 h. The impregnated molecular sieves were then heated to 900 °C for 4 h under a nitrogen atmosphere.

[0108] (3) Modified VOCs S Methods for preparing adsorbents

[0109] Same as (3) in Example 1.

[0110] Example 5:

[0111] (1) Preparation method of 13X molecular sieve seed crystals

[0112] Same as (1) in Example 1.

[0113] (2) Preparation method of carbon-modified 13X molecular sieve

[0114] The difference from Example 1 is that in step (3) of this example, the 13X molecular sieve is immersed in 100 mL of a 5 wt% benzene solution (carbon source: benzene, solvent: ethanol) and stirred for 10 h. Under a nitrogen atmosphere, the immersed molecular sieve is heated to 1000 °C for 1 h.

[0115] (3) Modified VOCs S Methods for preparing adsorbents

[0116] Same as (3) in Example 1.

[0117] Example 6:

[0118] (1) Preparation method of 13X molecular sieve seed crystals

[0119] Same as (1) in Example 1.

[0120] (2) Preparation method of carbon-modified 13X molecular sieve

[0121] The difference from Example 1 is that in step (3) of this example, the 13X molecular sieve is immersed in 100 mL of a 25 wt% benzene solution (carbon source: benzene, solvent: ethanol) and stirred for 36 h. Under a nitrogen atmosphere, the immersed molecular sieve is heated to 500 °C for 5 h.

[0122] (3) Modified VOCs S Methods for preparing adsorbents

[0123] Same as (3) in Example 1.

[0124] Example 7:

[0125] (1) Preparation method of 13X molecular sieve seed crystals

[0126] 1g of silicon powder was dissolved in 18g of deionized water and pretreated in a sealed reactor at 60℃ and 800rpm for 0.1h to obtain an aqueous solution of the silicon source dispersion.

[0127] 12 g of aluminum nitrate was dissolved in 18.0 g of deionized water and stirred at 60 °C and 800 rpm for 0.1 h to prepare an aqueous dispersion of the aluminum source. The prepared aqueous aluminum source solution was slowly added dropwise to the aqueous silicon source solution, and stirring was continued at 20 °C for 24 h to obtain a gel solution.

[0128] Dissolve 2g of sodium hydroxide in 36g of deionized water to prepare a dispersion, and slowly add it to the gel solution, controlling the pH value at 11.8. Then, transfer the mixed gel solution to a hydrothermal reactor and perform a two-stage temperature-controlled crystallization process: the first stage crystallization temperature is set at 60℃ for 4 hours; the second stage crystallization temperature is controlled at 120℃ for 6 hours. During the crystallization process, deionized water is added as needed to obtain a seed crystal solution.

[0129] In this crystallized product, the molar ratio of SiO2 to Al2O3 is 0.6:1, the molar ratio of Na2O to SiO2 is 3:1, and the molar ratio of H2O to SiO2 is 20:1.

[0130] (2) Preparation method of carbon-modified 13X molecular sieve

[0131] Same as (2) in Example 1.

[0132] (3) Modified VOCs S Methods for preparing adsorbents

[0133] Same as (3) in Example 1.

[0134] Example 8:

[0135] (1) Preparation method of 13X molecular sieve seed crystals

[0136] 0.17g of silicon powder was dissolved in 6g of deionized water and pretreated in a sealed reactor at 20°C and 200rpm for 12h to obtain a dispersed aqueous solution of silicon source.

[0137] 12 g of aluminum nitrate was dissolved in 18.0 g of deionized water and stirred at 20 °C and 200 rpm for 12 h to prepare an aqueous dispersion of the aluminum source. The aluminum source solution was slowly added to the silicon source solution and stirred at 100 °C for 0.1 h to obtain a gel solution.

[0138] 0.9 g of sodium hydroxide was dissolved in 6 g of deionized water to prepare a dispersion, which was then slowly added to the gel solution, and the pH was adjusted to 12.5. The prepared gel was then poured into a hydrothermal reactor for two-stage crystallization. First, crystallization was carried out at 20°C for 24 hours, followed by a second crystallization reaction at 80°C for 6 hours. Deionized water was added as needed during the crystallization process to obtain a seed crystal solution.

[0139] In this crystallized product, the molar ratio of SiO2 to Al2O3 is 0.1:1, the molar ratio of Na2O to SiO2 is 4:1, and the molar ratio of H2O to SiO2 is 1:1.

[0140] (2) Preparation method of carbon-modified 13X molecular sieve

[0141] Same as (2) in Example 1.

[0142] (3) Modified VOCs S Methods for preparing adsorbents

[0143] Same as (3) in Example 1.

[0144] Comparative Example 1

[0145] (1) Preparation method of 13X molecular sieve seed crystals

[0146] Same as (1) in Example 1.

[0147] (2) Preparation method of carbon-modified 13X molecular sieve

[0148] The difference from Example 1 is that no carbon modification step is performed, resulting in a 13X molecular sieve that has not undergone carbon modification.

[0149] (3) Modified VOCs S Methods for preparing adsorbents

[0150] Same as (3) in Example 1.

[0151] Comparative Example 2

[0152] (1) Preparation method of 13X molecular sieve seed crystals

[0153] The difference from Example 1 is that segmented crystallization was not used; the gel solution was directly regarded as the final gel system after mixing.

[0154] (2) Preparation method of carbon-modified 13X molecular sieve

[0155] The difference from Example 1 is that no carbon modification step is performed, resulting in a 13X molecular sieve that has not undergone carbon modification.

[0156] In addition, the step of introducing spent catalyst becomes:

[0157] The product was calcined at 50℃ for 120 min to obtain the calcined product. The calcined product was dissolved using a 25% nitric acid solution and filtered to obtain an aluminum-rich liquid for later use. 10g of the filtered residue, 6g of NaOH, and 40g of H2O were mixed evenly and filtered to obtain a silicon-rich liquid. The aluminum-rich liquid and the silicon-rich liquid were mixed at a mass ratio of 1:4 to obtain a gel mother liquor.

[0158] 25g of the gel system was added to the gel mother liquor and placed in a hydrothermal reaction for crystallization treatment at 100℃ for 24 hours. The reaction product was filtered, washed, and adjusted to pH 7. It was then dried at 90℃ to obtain 13X molecular sieve with a silica-alumina ratio of 2.22.

[0159] (3) Modified VOCsS Methods for preparing adsorbents

[0160] Same as (3) in Example 1.

[0161] Comparative Example 3

[0162] (1) Preparation method of 13X molecular sieve seed crystals

[0163] The difference from Example 1 is that the preparation of 13X molecular sieve seeds is not carried out, this step is omitted, and the experiment starts directly from step (2) of Comparative Example 3.

[0164] (2) Preparation method of carbon-modified 13X molecular sieve

[0165] The difference from Example 1 is that no carbon modification step is performed, resulting in a 13X molecular sieve that has not undergone carbon modification.

[0166] When preparing the gel mother liquor, the ratio of aluminum-rich source to silicon-rich liquid was changed to 1:9.5. The mixture was stirred and aged at 70°C for 15 hours. It was then placed in a hydrothermal reaction for crystallization at 105°C for 20 hours. The reaction product was filtered, washed, and adjusted to pH 7. It was then dried at 90°C to obtain 13X molecular sieve.

[0167] (3) Modified VOCs S Methods for preparing adsorbents

[0168] Same as (3) in Example 1.

[0169] Comparative Example 4

[0170] (1) Preparation method of 13X molecular sieve seed crystals

[0171] The difference from Example 1 is that segmented crystallization was not used in the preparation.

[0172] 12.5 g of boehmite was dissolved in 25.0 g of deionized water and stirred at 25 °C for 1 h to obtain an aqueous solution of the dispersed phase of the aluminum source. 100.0 g of water glass (mass fraction 28%) was dissolved in 18.0 g of deionized water to obtain an aqueous solution of the dispersed phase of the silicon source.

[0173] An aqueous solution of silicon source was slowly added dropwise to an aqueous solution of aluminum source, and the mixture was stirred at 45°C for 24 hours to obtain a gel solution. 20.2 g of sodium hydroxide dissolved in 15 g of deionized water dispersion was added to the gel solution, and the pH was maintained at 13.0 to obtain the gel system.

[0174] (2) Preparation method of carbon-modified 13X molecular sieve

[0175] The difference from Example 1 is that no waste catalyst was introduced and no carbon modification was performed. The gel system in (1) was directly placed into a hydrothermal reactor for temperature-controlled crystallization. The crystallization temperature was 100°C and the time was 18h. The reaction product was filtered and washed, the pH was adjusted to 7, and dried at 90°C to obtain 13X molecular sieve.

[0176] (3) Modified VOCs S Methods for preparing adsorbents

[0177] Same as (3) in Example 1.

[0178] Comparative Example 5

[0179] (1) Preparation method of 13X molecular sieve seed crystals

[0180] Same as (1) in Example 1.

[0181] (2) Preparation method of carbon-modified 13X molecular sieve

[0182] Same as (2) in Example 1.

[0183] (3) Modified VOCs S Methods for preparing adsorbents

[0184] The difference from Example 1 is that cerium ions were not introduced.

[0185] Test method:

[0186] Molar ratio, silicon-to-aluminum ratio: X-ray fluorescence spectroscopy (XRF);

[0187] Pore ​​volume and specific surface area: BET test method;

[0188] Adsorption performance: Fixed bed adsorption experiment: Ethylene was used as the adsorbent and passed through a fixed bed containing adsorbent. The concentration change through the bed was monitored. The adsorption capacity was determined by the weight of adsorbed ethylene (mg) / weight of adsorbent (g), with the unit being mg / g.

[0189] The specific surface area, pore volume, and silica-alumina ratio of the molecular sieves prepared in the above embodiments and comparative examples, as well as the adsorption capacity of the prepared modified VOCs adsorbents, are shown in Table 1.

[0190] Table 1:

[0191]

[0192]

[0193] The composition of the spent catalyst used in the above embodiments and comparative examples is shown in Table 2.

[0194] Table 2:

[0195] waste catalyst name <![CDATA[Fe2O3 / wt%]]> <![CDATA[Al2O3 / wt%]]> <![CDATA[SiO2 / wt%]]> <![CDATA[SO3 / wt%]]> CaO / wt% Waste ZSM-5 molecular sieve catalyst 0.050 19.84 79.64 0.31 0.18 Waste 13X adsorbent 0.020 72.36 18.0 0.024 0.042 .

[0196] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: The present invention introduces cerium ions into carbon-modified 13X molecular sieves, and after successively undergoing alkali treatment and a first calcination, introduces siloxane groups to obtain the modified VOCs adsorbent of the present invention. The VOCs adsorbent obtained by the present invention... S Adsorbents possess excellent physicochemical properties and environmental adaptability, making them suitable for environmental protection applications in various fields, especially industrial emissions and indoor air purification. They provide an efficient and environmentally friendly technical solution for effectively controlling and reducing VOCs pollution.

[0197] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a modified VOCs adsorbent, characterized in that, The preparation method includes: Introducing cerium ions into carbon-modified 13X molecular sieves yields cerium ion-containing molecular sieves. The cerium-containing molecular sieve was subjected to alkali treatment and a first calcination in sequence to obtain the adsorbent precursor; The modified VOCs adsorbent is obtained by introducing siloxane groups into the adsorbent precursor. The preparation method of the carbon-modified 13X molecular sieve includes: Step S1: Mix the aluminum source and silicon source with water respectively to obtain aluminum-containing materials and silicon-containing materials; Step S2: Mix the aluminum-containing material and the silicon-containing material, and sequentially perform the first stirring, pH adjustment and two-stage crystallization treatment to obtain the crystallized product; Step S3: The material containing molecular sieves is subjected to aluminum and silicon dissolution treatment to obtain aluminum-rich liquid and silicon-rich liquid, and the two are mixed to obtain gel-like mother liquor; Step S4: Mix the crystallized product from step S2 and the gel-like mother liquor from step S3, and after aging, hydrothermal crystallization, filtration, washing and drying, immerse it in a carbon precursor solution, calcine and shape it under an inert gas atmosphere to obtain the carbon-modified 13X molecular sieve. The first stage of the two-stage crystallization process involves a crystallization temperature of 20-60℃ and a crystallization time of 4-24h; the second stage involves a crystallization temperature of 80-120℃ and a crystallization time of 6-48h; and the two-stage crystallization process is carried out in a hydrothermal reactor.

2. The preparation method according to claim 1, characterized in that, The preparation method includes: The carbon-modified 13X molecular sieve was immersed in a cerium ion-containing solution for ion exchange to obtain the cerium ion-containing molecular sieve. The cerium-containing molecular sieve is immersed in an alkaline solution and then subjected to the first calcination to obtain the adsorbent precursor. The adsorbent precursor is immersed in a mixture of silane and alcohol to introduce the siloxane group, thereby obtaining the modified VOCs adsorbent.

3. The preparation method according to claim 2, characterized in that, The cerium source in the cerium-containing solution is selected from any one or more of the following: cerium chloride, cerium nitrate, cerium citrate, or cerium acetate.

4. The preparation method according to claim 3, characterized in that, The molar concentration of the cerium ion-containing solution is 0.05~0.5 mol / L.

5. The preparation method according to claim 3, characterized in that, The mass ratio of the carbon-modified 13X molecular sieve to the volume ratio of the cerium ion-containing solution is 1~20:100g / mL.

6. The preparation method according to claim 3, characterized in that, The ion exchange time is 22-26 hours.

7. The preparation method according to claim 3, characterized in that, The carbon-modified 13X molecular sieve requires a first drying process after ion exchange.

8. The preparation method according to claim 7, characterized in that, The first drying process is carried out at a temperature of 100-120°C for 10-14 hours.

9. The preparation method according to claim 2, characterized in that, The molar concentration of the alkaline solution is 2~2.5 mol / L.

10. The preparation method according to claim 9, characterized in that, The alkaline solution is selected from any one or more of the following: NaOH solution, KOH solution, or ammonia solution.

11. The preparation method according to claim 9, characterized in that, The cerium-containing molecular sieve is immersed in the alkaline solution for 1-3 hours and then subjected to the first calcination to obtain the adsorbent precursor.

12. The preparation method according to claim 9, characterized in that, The first calcination is carried out at a temperature of 400-600℃ for 4-8 hours.

13. The preparation method according to claim 2, characterized in that, The silane is selected from any one or more of the following: ethyltriethoxysilane, methyltrimethoxysilane, or propenyltrimethoxysilane; the alcohol is selected from any one or more of the following: ethanol, propanol, or butanol.

14. The preparation method according to claim 13, characterized in that, The silane and the alcohol are mixed in a volume ratio of 1:8 to 1:10 to form the mixture.

15. The preparation method according to claim 13, characterized in that, The adsorbent precursor is immersed in the mixture for 12-24 hours.

16. The preparation method according to claim 13, characterized in that, After the adsorbent precursor is immersed in the mixture and before the modified VOCs adsorbent is obtained, the preparation method further includes the steps of drying and calcining the adsorbent precursor after immersion in the mixture in sequence, wherein the temperature of the second calcination is 500~700℃ and the time is 2~4h.

17. The preparation method according to claim 1, characterized in that, In step S1, the aluminum source is selected from any one or more of the following: sodium aluminate, boehmite, aluminum sulfate, or aluminum nitrate.

18. The preparation method according to claim 1, characterized in that, In step S1, the silicon source is selected from any one or more of the following: silica sol, tetraethyl orthosilicate, coarse-porous silica gel, silicon powder, fly ash, or silica.

19. The preparation method according to claim 1, characterized in that, The conditions for mixing the silicon source and the water are: stirring at 20~60℃ for 0.1~12h, with the stirring speed being 200~800rpm; and the concentration of the silicon-containing material being 28~99wt%.

20. The preparation method according to claim 1, characterized in that, The conditions for mixing the aluminum source and the water are: stirring for 0.1 to 12 hours at 20 to 60°C, with the stirring speed being 200 to 800 rpm; and the concentration of the aluminum-containing material being 15 to 99 wt%.

21. The preparation method according to claim 1, characterized in that, The conditions for the first stirring described in step S2 are stirring at 20~100℃ for 0.1~24h.

22. The preparation method according to claim 1, characterized in that, The temperature of the second crystallization stage is higher than that of the first crystallization stage, with a difference of ≥40℃.

23. The preparation method according to claim 1, characterized in that, The molar ratios of the components in the crystallized product are SiO2 / Al2O3 = 0.01~2.5:1, Na2O / SiO2 = 0.01~4.0:1, and H2O / SiO2 = 1.0~40.0:

1.

24. The preparation method according to claim 1, characterized in that, The molecular sieve-containing material is selected from any one or more of the following: waste ZSM-5 molecular sieve catalyst, waste MTO catalyst, waste molecular sieve adsorbent, waste FCC catalyst, or waste VOCs adsorbent.

25. The preparation method according to claim 1, characterized in that, The steps of dissolving aluminum and dissolving silicon are as follows: (1) The molecular sieve material with a mesh size of less than 200 after grinding is mixed with Na2CO3 at a mass ratio of 1:0.5 to 1:5, calcined at 550 to 800°C for 60 to 120 minutes, and then dissolved in a monobasic acid with a mass fraction of 10% to 35%. After filtration, the aluminum-rich liquid is obtained. (2) The residue filtered in (1), NaOH and H2O are mixed evenly by a fourth stirring and filtered in a mass ratio of 0~100:40~60:50~400 to obtain the silicon-rich liquid; wherein the mass of the residue filtered in (1) is not 0.

26. The preparation method according to claim 1, characterized in that, The molar ratios of the components in the gel-like mother liquor are: SiO2 / Al2O3 = 0.5~6.0:1, Na2O / SiO2 = 0.5~6.0:1, and H2O / SiO2 = 10~100:

1.

27. The preparation method according to claim 1, characterized in that, The amount of the crystallized product added accounts for 5 to 20 wt% of the gel-like mother liquor.

28. The preparation method according to claim 1, characterized in that, The aging conditions are as follows: aging temperature is 20~100℃, aging time is 0.1~24h, and the aging process is carried out under the fifth stirring condition.

29. The preparation method according to claim 1, characterized in that, The carbon precursor solution is selected from any one or more of the following: benzene, furan, or furfural.

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