Modified molecular sieve for dehydrating corrosive gas as well as preparation method and application of modified molecular sieve
By loading metal oxides onto the molecular sieve body and coating it with a fluorosilicone layer, a modified molecular sieve was prepared, which solved the problem of easy structural collapse of adsorbent materials in a highly corrosive atmosphere. This achieved efficient and stable dehydration of corrosive gases, and is suitable for semiconductor chip manufacturing and display panel processes.
Patent Information
- Application Number
- CN202511874420.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-12
- Publication Date
- 2026-02-10
AI Technical Summary
Existing adsorption materials are easily corroded and dissolved by acids in highly corrosive atmospheres, resulting in a rapid decline in adsorption performance and difficulty in meeting ppb-level drying requirements. Furthermore, traditional methods have high equipment costs and potential risks of secondary pollution.
A modified molecular sieve is prepared by loading metal oxides onto the molecular sieve body to form a metal oxide-doped molecular sieve core, and then coating it with a fluorosilicified coating layer containing Si-F bonds. The modified molecular sieve is then shaped by specific calcination and activation treatments combined with an inorganic binder.
It maintains good performance in highly corrosive gas environments, with a structure retention rate of ≥95%, residual water content after dehydration ≤1ppm, and a cyclic adsorption retention rate of ≥90%, making it suitable for the purification of electronic gases and specialty gases.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of gas purification and adsorption separation technology, specifically relating to a modified molecular sieve for dehydrating corrosive gases, its preparation method, and its application. Background Technology
[0002] High-purity corrosive electronic gases are essential raw materials for semiconductor chip manufacturing, display panel processes, and other fields. With the continuous shrinking of integrated circuit feature sizes and the upgrading of process technology, the corrosive electronic gases used in etching, cleaning, doping, and other processes have faced more stringent requirements for impurity control, with moisture content needing to be controlled at the nL / L (ppb) level or even lower.
[0003] However, in actual preparation and purification processes, trace amounts of water are extremely difficult to remove completely. This is because water molecules readily form hydrogen-bonded complexes with impurities or gas molecules in the system, increasing the difficulty of removal. Residual water readily reacts with gases in acidic or corrosive atmospheres to form acidic condensates or corrosive droplets, leading to equipment corrosion, pipeline blockage, and consequently severely affecting product purity and safety in use.
[0004] Currently, the main methods for removing moisture from corrosive gases (especially electronic-grade hydrogen bromide, HBr) include distillation, chemical reaction, and adsorption. Distillation utilizes the difference in boiling points between water and the main component for separation, but this method requires extremely high-quality equipment, necessitating the use of special corrosion-resistant alloys or lining materials, resulting in high equipment investment and operating costs. Furthermore, due to the limited interaction between water and gases such as HBr, the water removal efficiency of distillation is limited, often failing to meet ppb-level drying requirements. Chemical reaction removes water by introducing reactive reagents to react with water, but this method carries the potential risk of secondary contamination: new products generated during the reaction may remain in the system or react with the target gas, introducing new impurities and increasing the burden on subsequent purification. In contrast, adsorption, with its advantages of simple operation, high water removal efficiency, ability to operate at low temperatures, and lack of introduction of new impurities, is considered the preferred solution for removing trace amounts of moisture from corrosive electronic gases. However, existing adsorption materials still have significant shortcomings. Commonly used desiccants, such as 3A, 4A, and 13X molecular sieves, are prone to framework structure destruction and loss of surface active centers in atmospheres such as HF, HCl, and HBr, resulting in a rapid decline in their adsorption performance and short cycle life. Furthermore, these traditional molecular sieves are easily corroded and dissolved by acids in highly corrosive gas environments, leading to adsorbent pulverization or precipitation of metallic impurities, further reducing product purity. Summary of the Invention
[0005] This invention addresses the shortcomings of existing technologies by providing a modified molecular sieve for dehydrating corrosive gases, its preparation method, and its applications.
[0006] To achieve the objectives of this invention, the technical solution adopted is as follows: The first aspect of the present invention provides a modified molecular sieve for dehydrating corrosive gases, wherein the modified molecular sieve has a metal oxide loaded on a molecular sieve body to form a metal oxide-doped molecular sieve core, and the metal oxide-doped molecular sieve core is coated with a fluorosilicified coating layer containing Si-F bonds; wherein the metal oxide is ZrO2 or TiO2.
[0007] Preferably, the molecular sieve body is a Y-type molecular sieve or a 13X molecular sieve.
[0008] Preferably, the modified molecular sieve also includes an inorganic binder.
[0009] A second aspect of this invention provides a method for preparing the modified molecular sieve for dehydrating corrosive gases as described in the first aspect, comprising the following steps: (1) The molecular sieve body is placed in a metal salt solution, stirred and impregnated, separated, dried and then calcined at 400-700℃ for 2-6 h to obtain a metal oxide doped molecular sieve; (2) Place the metal oxide doped molecular sieve prepared in step (1) in a reactor, introduce SiF4 gas or monofluorosilane gas, and react at 80-250℃ for 0.5-6 h to obtain the fluorosilicified molecular sieve. (3) The fluorosilicified molecular sieve prepared in step (2) is placed in an inert atmosphere and calcined at 250-450°C for 1-4 h, and then activated at 150-250°C for 1-6 h to obtain the activated molecular sieve. (4) The activated molecular sieve prepared in step (3) is mixed with an inorganic binder, extruded and dried to obtain a modified molecular sieve for dehydration of corrosive gases.
[0010] Preferably, the metal ions in the metal salt solution in step (1) are Zr. 4+ or Ti 4+ The concentration of metal ions in the metal salt solution is 0.01–5 mol / L.
[0011] More preferably, the metal salt in step (1) is Zr(NO3)4 or TiCl4, and the concentration of metal ions in the metal salt solution in step (1) is 0.01 to 1 mol / L.
[0012] Preferably, in step (1), the mass ratio of the metal salt solution to the molecular sieve body is (1-10):1.
[0013] More preferably, in step (1), the mass ratio of the metal salt solution to the molecular sieve body is (1-8):1.
[0014] Preferably, the immersion temperature in step (1) is 20℃~80℃ and the immersion time is 1~8 h.
[0015] More preferably, the immersion temperature in step (1) is 50℃~70℃, and the immersion time is 2~6 h.
[0016] Preferably, the inorganic binder in step (4) is one of silica sol, montmorillonite, bentonite, alumina or clay.
[0017] Preferably, the mass ratio of the activated molecular sieve to the inorganic binder in step (4) is (6-9):1.
[0018] Preferably, in step (1), the metal oxide-doped molecular sieve is separated by filtration or centrifugation.
[0019] Preferably, the drying temperature in step (1) is 80-140°C and the drying time is 6-24 h.
[0020] More preferably, the drying temperature in step (1) is 100-120°C and the drying time is 12 h.
[0021] Preferably, step (1) calcination is carried out in air or an oxygen-containing atmosphere.
[0022] The third aspect of this invention provides an application of the modified molecular sieve for dehydrating corrosive gases described in the first aspect in the dehydration of corrosive gases.
[0023] Preferably, the corrosive gas is one of HCl, HBr, HF, and Cl2.
[0024] Compared with the prior art, the present invention has the following advantages: This invention provides a modified molecular sieve for dehydrating corrosive gases that maintains excellent performance even in highly corrosive gas environments such as HCl, HBr, HF, and Cl2, with a structure retention rate of ≥95%, residual water content ≤1ppm after dehydration, a regeneration temperature of only 200℃, and a cyclic adsorption retention rate of ≥90%. Its preparation process is clear and controllable, solving the problems of easy structural collapse and decreased activity in traditional molecular sieves, and overcoming the shortcomings of existing modification methods. It is suitable for the purification processes of electronic gases and specialty gases, and has a wide range of applications. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention is further described in detail below through embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0026] Example 1 A modified molecular sieve for dehydrating corrosive gases, wherein the modified molecular sieve has a metal oxide-doped molecular sieve core formed by loading ZrO2 metal oxide onto a Y-type molecular sieve body, and the metal oxide-doped molecular sieve core is coated with a fluorosilicified coating layer containing Si-F bonds.
[0027] The specific steps of the preparation method of the modified molecular sieve for dehydration of corrosive gases are as follows: (1) Prepare a metal salt solution with a concentration of 0.5 mol / L for Zr(NO3)4. Place the molecular sieve in the metal salt solution with a mass ratio of 1:1 to the dry Y-type molecular sieve and stir at 50 °C for 2 h for impregnation. Filter the impregnated molecular sieve and dry it at 100 °C for 12 h. Calcine the dried molecular sieve at 500 °C for 2 h in air atmosphere to obtain ZrO2-doped molecular sieve. (2) The ZrO2-doped molecular sieve prepared in step (1) was placed in a reactor, and SiF4 gas was introduced at 20 mL / min. The surface was fluorinated and siliconized at 100 °C for 2 h to obtain the fluorinated and siliconized molecular sieve. (3) The fluorosilicified molecular sieve prepared in step (2) was placed in a nitrogen atmosphere and cured and calcined at 350°C for 2 hours, and then activated at 200°C for 2 hours in a nitrogen atmosphere. (4) The activated molecular sieve and silica sol are mixed at a mass ratio of 8:1, extruded and dried to obtain a modified molecular sieve for dehydration of corrosive gases.
[0028] Example 2 A modified molecular sieve for dehydrating corrosive gases, wherein the modified molecular sieve has a metal oxide-doped molecular sieve core formed by loading TiO2 metal oxide onto a Y-type molecular sieve body, and the metal oxide-doped molecular sieve core is coated with a fluorosilicified coating layer containing Si-F bonds.
[0029] The specific steps of the preparation method of the modified molecular sieve for dehydration of corrosive gases are as follows: (1) Prepare a metal salt solution with a concentration of 0.5 mol / L using TiCl4. Place the molecular sieve in the metal salt solution with a mass ratio of 1:1 to the dry Y-type molecular sieve and stir at 50 °C for 2 h for impregnation. Filter the impregnated molecular sieve and dry it at 100 °C for 12 h. Calcine the dried molecular sieve at 500 °C for 2 h in air atmosphere to obtain TiO2-doped molecular sieve. (2) The TiO2-doped molecular sieve prepared in step (1) is placed in a reactor, and SiF4 gas is introduced at 20 mL / min. The surface is fluorinated and siliconized at 100 °C for 2 h to obtain the fluorinated and siliconized molecular sieve. (3) The fluorosilicified molecular sieve prepared in step (2) was placed in a nitrogen atmosphere and cured and calcined at 350°C for 2 hours, and then activated at 200°C for 2 hours in a nitrogen atmosphere. (4) The activated molecular sieve and silica sol are mixed at a mass ratio of 8:1, extruded and dried to obtain a modified molecular sieve for dehydration of corrosive gases.
[0030] Example 3 A modified molecular sieve for dehydrating corrosive gases, wherein the modified molecular sieve has a metal oxide-doped molecular sieve core formed by loading ZrO2 metal oxide onto a Y-type molecular sieve body, and the metal oxide-doped molecular sieve core is coated with a fluorosilicified coating layer containing Si-F bonds.
[0031] The specific steps of the preparation method of the modified molecular sieve for dehydration of corrosive gases are as follows: (1) Prepare a metal salt solution with a concentration of 0.5 mol / L for Zr(NO3)4. Place the molecular sieve in the metal salt solution at a mass ratio of 3:1 and stir at 50 °C for 2 h for impregnation. Filter the impregnated molecular sieve and dry it at 100 °C for 12 h. Calcine the dried molecular sieve at 500 °C for 2 h in air atmosphere to obtain ZrO2-doped molecular sieve. (2) The ZrO2-doped molecular sieve prepared in step (1) was placed in a reactor, and SiF4 gas was introduced at 20 mL / min. The surface was fluorinated and siliconized at 100 °C for 2 h to obtain the fluorinated and siliconized molecular sieve. (3) The fluorosilicified molecular sieve prepared in step (2) was placed in a nitrogen atmosphere and cured and calcined at 350°C for 2 hours, and then activated at 200°C for 2 hours in a nitrogen atmosphere. (4) The activated molecular sieve and silica sol are mixed at a mass ratio of 8:1, extruded and dried to obtain a modified molecular sieve for dehydration of corrosive gases.
[0032] Example 4 A modified molecular sieve for dehydrating corrosive gases, wherein the modified molecular sieve has a metal oxide-doped molecular sieve core formed by loading ZrO2 metal oxide onto a Y-type molecular sieve body, and the metal oxide-doped molecular sieve core is coated with a fluorosilicified coating layer containing Si-F bonds.
[0033] The specific steps of the preparation method of the modified molecular sieve for dehydration of corrosive gases are as follows: (1) Prepare a metal salt solution with a concentration of 0.5 mol / L for Zr(NO3)4. Place the molecular sieve in the metal salt solution with a mass ratio of 5:1 to dry Y-type molecular sieve and stir at 50 °C for 2 h for impregnation. Filter the impregnated molecular sieve and dry it at 100 °C for 12 h. Calcine the dried molecular sieve at 500 °C for 2 h in air atmosphere to obtain ZrO2-doped molecular sieve. (2) The ZrO2-doped molecular sieve prepared in step (1) was placed in a reactor, and SiF4 gas was introduced at 20 mL / min. The surface was fluorinated and siliconized at 100 °C for 2 h to obtain the fluorinated and siliconized molecular sieve. (3) The fluorosilicified molecular sieve prepared in step (2) was placed in a nitrogen atmosphere and cured and calcined at 350°C for 2 hours, and then activated at 200°C for 2 hours in a nitrogen atmosphere. (4) The activated molecular sieve and silica sol are mixed at a mass ratio of 8:1, extruded and dried to obtain a modified molecular sieve for dehydration of corrosive gases.
[0034] Example 5 A modified molecular sieve for dehydrating corrosive gases, wherein the modified molecular sieve has a metal oxide-doped molecular sieve core formed by loading ZrO2 metal oxide onto a Y-type molecular sieve body, and the metal oxide-doped molecular sieve core is coated with a fluorosilicified coating layer containing Si-F bonds.
[0035] The specific steps of the preparation method of the modified molecular sieve for dehydration of corrosive gases are as follows: (1) Prepare a metal salt solution with a concentration of 0.5 mol / L for Zr(NO3)4. Place the molecular sieve in the metal salt solution according to the mass ratio of metal salt solution to dry Y-type molecular sieve of 8:1 and stir at 50 °C for 2 h for impregnation. Filter the impregnated molecular sieve and dry it at 100 °C for 12 h. Calcine the dried molecular sieve at 500 °C for 2 h in air atmosphere to obtain ZrO2-doped molecular sieve. (2) The ZrO2-doped molecular sieve prepared in step (1) was placed in a reactor, and SiF4 gas was introduced at 20 mL / min. The surface was fluorinated and siliconized at 100 °C for 2 h to obtain the fluorinated and siliconized molecular sieve. (3) The fluorosilicified molecular sieve prepared in step (2) was placed in a nitrogen atmosphere and cured and calcined at 350°C for 2 hours, and then activated at 200°C for 2 hours in a nitrogen atmosphere. (4) The activated molecular sieve and silica sol are mixed at a mass ratio of 8:1, extruded and dried to obtain a modified molecular sieve for dehydration of corrosive gases.
[0036] Performance testing (1) Adsorption performance The modified molecular sieves for dehydrating corrosive gases prepared in Examples 1 to 5 were packed into adsorption columns, with a loading of 50 g of modified molecular sieve in each column. HBr gas with a water content of 30 ppm was used as the target gas for continuous adsorption experiments, with the gas flow rate controlled at 1 L / min during the experiment. The moisture content of the outlet gas after 24 hours of adsorption is shown in Table 1.
[0037] Table 1. Results of moisture adsorption tests for different embodiments Table 1 shows the experimental data. In Examples 1 and 2, modified molecular sieves were prepared using Y-type molecular sieves supported by different metal oxides. The modified molecular sieve in Example 1, supported by ZrO2 metal oxide, exhibited better adsorption performance. This is because ZrO2 has stronger Lewis acidity and better surface hydroxyl stability compared to TiO2, enhancing the adsorption of polar water molecules. Examples 1 to 5 prepared modified molecular sieves with different mass ratios of metal salt solution and dried Y-type molecular sieve. As the mass of the metal salt solution increased, the adsorption performance of the modified molecular sieve first increased and then decreased. This is because at low mass ratios, the active component loaded on the molecular sieve surface was insufficient, resulting in fewer adsorption sites. With increasing mass ratio, the loading of active component increased, enhancing the adsorption performance. However, excessively high mass ratios caused blockage of the molecular sieve pores, leading to a decrease in adsorption performance. The modified molecular sieves prepared in Examples 1 to 5 for dehydrating corrosive gases can effectively reduce the water content in HBr gas to below 1 ppm, with the optimal dehydration depth reaching 0.32 ppm. Throughout the adsorption process, the temperature inside the adsorption column rose from 26℃ to 28℃, but the temperature rise was not significant.
[0038] (2) Cyclic performance test The modified molecular sieve prepared in Example 4 was used for recycling performance testing. After one use, the molecular sieve was continuously treated at 200°C under a high-purity nitrogen atmosphere for 48 hours; this process was defined as one regeneration. The dehydration effect of the molecular sieve before and after regeneration is shown in Table 2.
[0039] Table 2 Comparison of dehydration effects of the modified molecular sieve in Example 4 before and after regeneration As shown in Table 2, the adsorption capacity of the modified molecular sieve after 20 regenerations is not significantly different from that of the modified molecular sieve for dehydration of corrosive gases prepared in Example 4. Moreover, the multiple adsorption-regeneration cycles did not cause significant damage to its framework structure. This indicates that the molecular sieve of Example 4 has high adsorption efficiency, large adsorption capacity, excellent structural stability and regeneration repeatability, and can meet the repeated recycling needs in large-scale industrial continuous production. Its practicality and reliability are outstanding.
[0040] Comparative Example 1 Y-type molecular sieve from Nanjing Chemical (Tianjin) Catalyst Co., Ltd. was selected as a comparative example, and its recycling performance was compared with that of the modified molecular sieve used for corrosive gas dehydration in Example 4. During continuous operation, the changes in moisture content at the inlet and outlet were monitored, and the results are shown in Table 3.
[0041] Table 3 Comparison of dewatering performance between modified molecular sieve and Y-type molecular sieve in Example 4 As shown in Table 3, although the Y molecular sieve initially exhibited a certain water absorption capacity, its water absorption effect significantly decreased after 10 regeneration cycles, becoming almost ineffective in reducing the moisture content in HBr gas. Furthermore, after multiple regeneration processes, the crystallinity of the Y molecular sieve dropped sharply from over 90% initially to 20%, indicating severe structural damage and a significant decline in adsorption performance.
Claims
1. A modified molecular sieve for dehydrating corrosive gases, characterized in that, The modified molecular sieve has a metal oxide-doped molecular sieve core formed by loading a metal oxide onto the molecular sieve body, and the metal oxide-doped molecular sieve core is coated with a fluorosilicified coating layer containing Si-F bonds; the metal oxide is ZrO2 or TiO2.
2. The modified molecular sieve for dehydrating corrosive gases according to claim 1, characterized in that, The molecular sieve body is a Y-type molecular sieve or a 13X molecular sieve.
3. The modified molecular sieve for dehydrating corrosive gases according to claim 1 or 2, characterized in that, It also includes inorganic binders.
4. A method for preparing a modified molecular sieve for dehydrating corrosive gases according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) The molecular sieve body is placed in a metal salt solution, stirred and impregnated, separated, dried and then calcined at 400-700℃ for 2-6 h to obtain a metal oxide doped molecular sieve; (2) Place the metal oxide doped molecular sieve prepared in step (1) in a reactor, introduce SiF4 gas or monofluorosilane gas, and react at 80-250℃ for 0.5-6 h to obtain the fluorosilicified molecular sieve. (3) The fluorosilicified molecular sieve prepared in step (2) is placed in an inert atmosphere and calcined at 250-450°C for 1-4 hours, and then activated at 150-250°C for 1-6 hours to obtain the activated molecular sieve. (4) The activated molecular sieve prepared in step (3) is mixed with an inorganic binder, extruded and dried to obtain a modified molecular sieve for dehydration of corrosive gases.
5. The method for preparing the modified molecular sieve for dehydrating corrosive gases according to claim 2, characterized in that, Step (1) The metal ions in the metal salt solution are Zr 4+ or Ti 4+ The concentration of metal ions in the metal salt solution is 0.01–5 mol / L.
6. The method for preparing the modified molecular sieve for dehydrating corrosive gases according to claim 3, characterized in that, Step (1) The mass ratio of the metal salt solution to the molecular sieve body is (1-10):
1.
7. The method for preparing the modified molecular sieve for dehydrating corrosive gases according to claim 4, characterized in that, Step (1) The immersion temperature is 20℃~80℃ and the immersion time is 1~8 h.
8. The method for preparing the modified molecular sieve for dehydrating corrosive gases according to claim 2, characterized in that, Step (1) Separate the metal oxide-doped molecular sieve by filtration or centrifugation; Step (1) Drying temperature is 80-140℃ and drying time is 6-24 h; Step (1) Calcination is carried out in air or oxygen-containing atmosphere.
9. The application of the modified molecular sieve for corrosive gas dehydration as described in claim 1 in the dehydration of corrosive gases.
10. The application according to claim 9, characterized in that, The corrosive gas is one of HCl, HBr, HF, and Cl2.