Green synthesis method of Y molecular sieve

Abstract

The invention belongs to the field of material synthesis, and particularly relates to a green synthesis method of a Y molecular sieve, which comprises the following steps: (1) calcining coal gangue powder in an air atmosphere at 500-800 DEG C for 2-8 hours to remove pyrolyzable impurities; (2) uniformly mixing the calcined coal gangue powder obtained in the step (1) with sodium hydroxide, and calcining for 3-10 hours at 800 DEG C in an air atmosphere to activate silicon-aluminum species to obtain mixture powder; and (3) uniformly mixing and grinding the mixture powder obtained in the step (2) with a seed crystal, an inorganic ammonium salt and deionized water, transferring into a stainless steel reaction kettle with a polytetrafluoroethylene lining, crystallizing at 80-110 DEG C for 24-48 hours, and washing and drying a product to obtain the Y molecular sieve. The preparation method disclosed by the invention is simple in process, low in cost, free of waste liquid, environment-friendly, very high in practicability and good in industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of materials synthesis, and in particular relates to a green synthesis method for Y molecular sieve materials. Background Technology

[0002] Aluminosilicate molecular sieves possess abundant pores, a large specific surface area, and tunable acidity and alkalinity, making them widely used in catalysis, adsorption separation, and other fields. Y-type molecular sieves with a FAU structure are a typical example of aluminosilicate molecular sieves, and their outstanding performance in processes such as catalytic cracking has led to a huge global demand. The traditional synthesis method for Y-type molecular sieves is the hydrothermal method. Although it does not use expensive organic template agents, the large-scale use of conventional silicon and aluminum sources still results in high synthesis costs. Furthermore, the extensive use of solvents not only causes significant wastewater discharge but also significantly impacts product yield.

[0003] To reduce costs, the use of natural minerals or waste materials containing silicon and aluminum to replace conventional silicon and aluminum sources in the synthesis of molecular sieves has attracted widespread attention. For example, Liu et al. (Dalton Trans., 2023, 52, 24) used fly ash as the silicon and aluminum source to synthesize Y molecular sieves without solvents. However, their synthesis process required the addition of concentrated hydrochloric acid to adjust the pH, which increased the difficulty of the synthesis process, and the volatile hydrochloric acid also had a certain impact on the environment. Yang et al. (J.Environ. Chem.Eng., 2024, 12, 112413) also used a solid-phase method to synthesize X molecular sieves with the same FAU structure using fly ash as raw material. Although no strong acid was added during the synthesis process, the fly ash raw material needed to be purified with strong acid, which increased the complexity of the synthesis process, and the waste acid also caused environmental problems. Jiang Xiaye et al. (Henan Chemical Industry, 2025, 42, 14) synthesized NaX molecular sieves using coal gangue as raw material. The synthesis process utilized an alkaline solution to dissolve the coal gangue powder and was carried out in a hydrothermal system, thus not avoiding the drawbacks of traditional hydrothermal methods that rely heavily on solvents. In summary, developing simple, low-cost, and environmentally friendly synthetic methods to prepare FAU-structured molecular sieves is a common goal for researchers in this field. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of existing technologies, such as high cost, complicated steps, and harsh conditions, and provides a method for preparing Y molecular sieves that is simple in process, low in cost, environmentally friendly, and can significantly improve the flame retardancy of polyolefin polymer materials through synergistic intumescent flame retardants.

[0005] To solve the above-mentioned technical problems, the present invention is implemented as follows: A green synthesis method for Y molecular sieves includes the following steps: (1) First, calcine the coal gangue powder at 500-800℃ in air for 2-8 hours to remove pyrolytic impurities; (2) The calcined coal gangue powder obtained in step (1) is mixed evenly with sodium hydroxide and calcined at 800°C for 3 to 10 hours in air atmosphere to activate the silicon-aluminum species and obtain the mixture powder. (3) The mixture powder obtained in step (2) is mixed and ground evenly with seed crystals, inorganic ammonium salt, and deionized water, and then transferred to a stainless steel reactor with a polytetrafluoroethylene liner. It is crystallized at 80-110°C for 24-48 hours. The product is washed and dried to obtain Y molecular sieve. The Y molecular sieve has an FAU structure.

[0006] Further, in step (2), the mass ratio of coal gangue to sodium hydroxide is 1:0.9 to 1.2.

[0007] Further, in step (3), the mass ratio of the mixed powder to the seed crystal and deionized water is 1:0.025~0.1:0.33~0.66.

[0008] Furthermore, the sodium hydroxide in step (2) reacts with the NH4 in the inorganic ammonium salt in step (3). + The molar ratio is 1:0.50 to 0.55.

[0009] Furthermore, the seed crystal is a conventionally hydrothermally synthesized HY molecular sieve.

[0010] Furthermore, the inorganic ammonium salt is at least one of ammonium chloride, ammonium sulfate, and ammonium nitrate.

[0011] The product obtained by the above-mentioned green synthesis method of Y molecular sieve is used in the application of synergistic intumescent flame retardants to improve the flame retardant properties of polyolefin polymer materials.

[0012] Compared with the prior art, the beneficial effects that the present invention can produce include: 1) The green synthesis method of Y molecular sieve provided in this application is simple and low in cost, overcomes the limitations of the existing technology with complicated steps and harsh conditions, and has no waste liquid discharge, which is environmentally friendly and has strong practicality, environmental protection and good prospects for industrial application.

[0013] 2) The green synthesis method of Y molecular sieve provided in this application can significantly improve the flame retardant properties of polyolefin polymer materials through synergistic intumescent flame retardants. Attached Figure Description

[0014] Figure 1 The image shows the XRD pattern of the Y molecular sieve obtained in Example 1 of this invention.

[0015] Figure 2This is a SEM image of the Y molecular sieve obtained in Example 1 of the present invention. Detailed Implementation

[0016] To enable those skilled in the art to better understand the technical solutions of this invention, the invention will be further described below with reference to specific embodiments. Obviously, the described embodiments are merely a part of the embodiments of this invention, and not all of them. These embodiments should be understood as being used only to illustrate the invention and not to limit the scope of protection of the invention. After reading the contents of this invention, all other embodiments obtained by making various modifications or alterations to the invention based on the technical solutions and embodiments of this invention also fall within the scope of protection of the claims of this invention.

[0017] The coal gangue powder used in this application has the following composition: SiO2: 63.99%, Al2O3: 25.06%, K2O+Na2O: 4.72%, Fe2O3: 3.72%, TiO2: 1.29%, CaO: 0.56%, MgO: 0.28%, P2O5: 0.087%. Unless otherwise specified, all the basic raw materials used in this application were commercially purchased and used directly without special treatment.

[0018] Example 1: Preparation of Materials Take an appropriate amount of coal gangue powder and place it in a muffle furnace. Calcinate at 800℃ for 2 hours in air atmosphere. Take 5g of the calcined coal gangue powder and mix it with 5g of sodium hydroxide. Grind the mixture evenly and calcine it in a muffle furnace at 800℃ for 6 hours in air atmosphere to activate the silicon-aluminum species. Take 1.5g of the activated mixed raw material, add 0.0375g of HY seed crystals, 0.5g of ammonium chloride, and 0.5g of deionized water. Mix and grind evenly, then transfer the mixture to a stainless steel reactor with a polytetrafluoroethylene liner. Allow it to crystallize in a 100℃ oven for 24 hours. After washing and drying, the product yields Y molecular sieve.

[0019] Example 2: Material Preparation Take an appropriate amount of coal gangue powder and place it in a muffle furnace. Calcinate at 800℃ for 2 hours in air atmosphere. Take 5g of the calcined coal gangue powder and mix it with 5g of sodium hydroxide. Grind the mixture evenly and calcine it in a muffle furnace at 800℃ for 6 hours in air atmosphere to activate the silicon-aluminum species. Take 1.5g of the activated mixed raw material, add 0.15g of HY seed crystals, 0.5g of ammonium chloride, and 0.5g of deionized water. Mix and grind evenly, then transfer the mixture to a stainless steel reactor with a polytetrafluoroethylene liner. Allow it to crystallize in a 100℃ oven for 24 hours. After washing and drying, the product yields Y molecular sieve.

[0020] Example 3: Preparation of Materials A suitable amount of coal gangue powder was placed in a muffle furnace and calcined at 500℃ for 8 hours in air atmosphere. 5g of the calcined coal gangue powder was mixed with 5g of sodium hydroxide and ground evenly. The mixture was then calcined in a muffle furnace at 800℃ for 10 hours in air atmosphere to activate the silicon-aluminum species. 1.5g of the activated mixed raw material was added to 0.0375g of HY seed crystals, 0.5g of ammonium chloride, and 0.5g of deionized water. The mixture was ground evenly and transferred to a stainless steel reactor with a polytetrafluoroethylene liner. The reactor was then allowed to stand and crystallize in a 100℃ oven for 24 hours. The product was washed and dried to obtain Y molecular sieve.

[0021] Example 4: Material Preparation Take an appropriate amount of coal gangue powder and place it in a muffle furnace. Calcinate at 800℃ for 2 hours in air atmosphere. Take 5g of the calcined coal gangue powder and mix it with 6g of sodium hydroxide. Grind the mixture evenly and calcine it in a muffle furnace at 800℃ for 6 hours in air atmosphere to activate the silicon-aluminum species. Take 1.5g of the activated mixed raw material, add 0.0375g of HY seed crystals, 0.547g of ammonium chloride, and 1.0g of deionized water. Mix and grind evenly, then transfer the mixture to a stainless steel reactor with a polytetrafluoroethylene liner. Allow it to crystallize in a 100℃ oven for 24 hours. After washing and drying, the product yields Y molecular sieve.

[0022] Example 5: Preparation of Materials Take an appropriate amount of coal gangue powder and place it in a muffle furnace. Calcinate at 800℃ for 2 hours in air atmosphere. Take 5g of calcined coal gangue powder and mix it with 5g of sodium hydroxide. Grind the mixture evenly and calcine it in a muffle furnace at 800℃ for 6 hours in air atmosphere to activate the silicon-aluminum species. Take 1.5g of the activated mixed raw material, add 0.0375g of HY seed crystals, 0.617g of ammonium sulfate, and 0.5g of deionized water. Mix and grind evenly, then transfer the mixture to a stainless steel reactor with a polytetrafluoroethylene liner. Allow it to crystallize in a 100℃ oven for 24 hours. After washing and drying, the product yields Y molecular sieve.

[0023] Example 6: Preparation of Materials Take an appropriate amount of coal gangue powder and place it in a muffle furnace. Calcinate at 800℃ for 2 hours in air atmosphere. Take 5g of the calcined coal gangue powder and mix it with 5g of sodium hydroxide. Grind the mixture evenly and calcine it in a muffle furnace at 800℃ for 6 hours in air atmosphere to activate the silicon-aluminum species. Take 1.5g of the activated mixed raw material, add 0.0375g of HY seed crystals, 0.747g of ammonium nitrate, and 0.5g of deionized water. Mix and grind evenly, then transfer the mixture to a stainless steel reactor with a polytetrafluoroethylene liner. Allow it to crystallize in a 100℃ oven for 48 hours. After washing and drying, the product yields Y molecular sieve.

[0024] Example 7 Application of Materials Ammonium polyphosphate and pentaerythritol were added to a high-speed mixer at a mass ratio of 3:1 and stirred until homogeneous to obtain an intumescent primary flame retardant. 18g of the intumescent flame retardant, 2.0g of the Y molecular sieve obtained in Example 1, and 80g of polypropylene were mixed and melt-granulated using a twin-screw extruder. The mixture was then compressed and molded using a flat vulcanizing machine, and cut into the required sample strips using a sample preparation machine. The flame retardant performance test results showed a limiting oxygen index of 30% and a peak heat release rate of 260.5 kW / m³. 2 Total heat release: 60.1 MJ / m 2 .

[0025] Comparative Example 1: Application of Materials Ammonium polyphosphate and pentaerythritol were added to a high-speed mixer at a mass ratio of 3:1 and stirred until homogeneous to obtain an intumescent primary flame retardant. 20g of the intumescent flame retardant was mixed with 80g of polypropylene, melt-granulated using a twin-screw extruder, compressed and molded using a flat vulcanizing machine, and cut into the required sample strips using a sample preparation machine. The flame retardant performance test results showed a limiting oxygen index of 26.8%, a peak heat release rate of 558.5 kW / m², and a total heat release of 103.8 MJ / m².

[0026] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A green synthesis method for Y molecular sieves, characterized in that, Includes the following steps: (1) First, calcine the coal gangue powder at 500-800℃ in air for 2-8 hours to remove pyrolytic impurities; (2) The calcined coal gangue powder obtained in step (1) is mixed evenly with sodium hydroxide and calcined at 800°C for 3 to 10 hours in air atmosphere to activate the silicon-aluminum species and obtain the mixture powder. (3) The mixture powder obtained in step (2) is mixed and ground evenly with seed crystals, inorganic ammonium salt and deionized water, and transferred to a stainless steel reactor with a polytetrafluoroethylene liner. It is crystallized at 80-110℃ for 24-48 hours. The product is washed and dried to obtain Y molecular sieve.

2. The green synthesis method of Y molecular sieve according to claim 1, characterized in that: In step (2), the mass ratio of coal gangue to sodium hydroxide is 1:0.9 to 1.

2.

3. The green synthesis method of Y molecular sieve according to claim 2, characterized in that: In step (3), the mass ratio of the mixed powder to the seed crystal and deionized water is 1:0.025-0.1:0.33-0.

66.

4. The green synthesis method of Y molecular sieve according to claim 2, characterized in that: In step (2), sodium hydroxide reacts with NH4 in the inorganic ammonium salt in step (3). + The molar ratio is 1:0.50 to 0.

55.

5. The green synthesis method of Y molecular sieve according to claim 3, characterized in that: The seed crystals are HY molecular sieves synthesized by conventional hydrothermal methods.

6. The green synthesis method of Y molecular sieve according to claim 5, characterized in that: The inorganic ammonium salt is one or a mixture of two or more of ammonium chloride, ammonium sulfate, and ammonium nitrate.

7. The application of the product obtained by the green synthesis method of Y molecular sieve as described in any one of claims 1 to 6 in improving the flame retardant properties of polyolefin polymer materials with synergistic intumescent flame retardants.

Images