Hydrophobic zeolite molecular sieve, preparation method thereof and application of hydrophobic zeolite molecular sieve in smoke CO2 capture
By forming a hydrophobic carbon layer on the surface of the 13X molecular sieve, the problem of degradation of CO2 adsorption performance in the water-containing gas of traditional zeolite molecular sieve is solved, and efficient CO2 capture and stability under high humidity conditions is achieved.
Patent Information
- Application Number
- CN202510258313.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-06-06
AI Technical Summary
The CO2 adsorption performance of traditional zeolite molecular sieve in aqueous flue gas has decreased, resulting in limited application.
By grafting the 13X molecular sieve with siloxane as a hydrophobic modifier, a hydrophobic carbon layer coated on the surface of the 13X molecular sieve is formed, and the physical and chemical properties of the surface are regulated and its hydrophobicity is improved.
It has achieved good CO2 adsorption efficiency and cycle stability under high humidity conditions, breaking the technical bottleneck of the reduction of CO2 adsorption under traditional zeolite molecular sieve under high humidity conditions.
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Figure CN120094549A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to CO 2 The invention relates to a hydrophobic zeolite molecular sieve and a preparation method thereof and a method for collecting CO in flue gas. 2 Capture applications. Background Art
[0002] Human industrial production leads to CO in the atmosphere 2 The concentration of industrial flue gas CO 2 The research and development of capture is of great significance. 2 In terms of capture, CO2 based on solid porous materials 2 Capture technology has the advantages of simple operation and low energy consumption, and has become a research hotspot. Among them, solid adsorbents represented by zeolite molecular sieves have the following advantages: (1) high specific surface area and adjustable pore structure, flexible adsorption site types, thereby achieving effective synergy between adsorption sites and significantly improving adsorption capacity; (2) good cycle performance, molecular sieves generally use skeleton structures to physically adsorb CO 2 , the adsorption heat is small, so the cycle energy consumption is low; (3) good stability. The synthesis of zeolite molecular sieves generally undergoes hydrothermal or high-temperature sintering and has good thermal stability.
[0003] However, zeolite molecular sieves are 2 The adsorption performance drops sharply, which seriously restricts its application. This is because water vapor and CO 2 There is competition: H 2 O is a polar molecule, while CO 2 It is a nonpolar molecule and reacts with CO 2 Compared with H 2 O is more likely to interact strongly with the adsorbent surface, thereby reducing CO 2 adsorption capacity.
[0004] In order to improve the hydrophobicity of zeolite molecular sieves, the existing main methods are to increase the silicon-aluminum ratio of zeolite, prepare pure silicon molecular sieves, construct polyester membranes or construct shell structures. However, the preparation process of these hydrophobically modified zeolite molecular sieves is relatively complicated and the feasibility of large-scale application is low. Summary of the invention
[0005] The present invention aims to provide a hydrophobic zeolite molecular sieve and a preparation method thereof and a method for treating flue gas CO 2 In the application of capture, the hydrophobic zeolite molecular sieve provided by the present invention has good adsorption effect and stability.
[0006] In order to achieve the above object, the present invention provides the following technical solutions:
[0007] The present invention provides a method for preparing a hydrophobic zeolite molecular sieve, comprising the following steps:
[0008] The 13X molecular sieve, a hydrophobic modifier and an organic solvent are mixed for grafting reaction and then activated to obtain the hydrophobic zeolite molecular sieve; the hydrophobic modifier includes siloxane.
[0009] Preferably, the 13X molecular sieve is dried before use, the drying temperature is 300° C., the rate of heating to the drying temperature is 8 to 10° C. / min, and the final temperature holding time is 6 to 8 hours.
[0010] Preferably, the 13X molecular sieve is soaked in water before drying and then solid-liquid separation is performed; the soaking time is 10 to 60 minutes.
[0011] Preferably, the temperature of the grafting reaction is 20-40° C., and the constant temperature reaction time is 24-36 hours.
[0012] Preferably, the activation temperature is 80-100° C., and the constant temperature activation time is 24-36 hours.
[0013] The present invention also provides a hydrophobic zeolite molecular sieve obtained by the preparation method described in the above scheme, comprising a 13X molecular sieve and a hydrophobic carbon layer coated on the surface of the 13X molecular sieve; the component of the hydrophobic carbon layer comprises siloxane.
[0014] Preferably, the siloxane includes one or more of hexyltrimethoxysilane, propyltrimethoxysilane and dodecyltrimethoxysilane.
[0015] Preferably, the mass ratio of the hydrophobic carbon layer to the 13X molecular sieve is 3-5:95-97.
[0016] Preferably, the particle size of the hydrophobic zeolite molecular sieve is 1 to 3 μm.
[0017] The present invention also provides the hydrophobic zeolite molecular sieve in the above scheme in flue gas CO 2 Capture applications.
[0018] The present invention provides a method for preparing a hydrophobic zeolite molecular sieve. The present invention forms a hydrophobic carbon layer by dealcoholization condensation between the methoxyl groups of siloxane and the silanol groups on the surface of 13X molecular sieve, thereby regulating the physical and chemical properties of the surface of 13X molecular sieve and reducing the H 2 Effect of O on the performance of 13X molecular sieve, improve the CO 2 The preparation method provided by the present invention has simple steps, low production cost, cheap and readily available raw materials, and is suitable for large-scale production and application.
[0019] The present invention also provides a hydrophobic zeolite molecular sieve obtained by the preparation method described in the above scheme. Compared with the traditional zeolite molecular sieve, the hydrophobic zeolite molecular sieve provided by the present invention retains the good adsorption performance of the 13X molecular sieve by implanting siloxane molecules with similar pore size, while enhancing the hydrophobicity of the 13X molecular sieve pores, and is suitable for high-humidity simulated flue gas CO 2 Capture, solve the problem of the traditional zeolite molecular sieve adsorption performance decline in water-containing flue gas. 2 O / CO 2 / N 2 =7 / 13 / 80, 30sccm), the adsorbent exhibited good adsorption performance and cycle stability.
[0020] The present invention also provides the hydrophobic zeolite molecular sieve in the above scheme in flue gas CO 2 The hydrophobic zeolite molecular sieve provided by the present invention has high adsorption efficiency and good stability, and is suitable for flue gas CO 2 Capture, especially suitable for CO2 2 Capture, breaking the traditional zeolite molecular sieve under high humidity conditions CO 2 Adsorption reduces the technical bottleneck. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0022] Figure 1 This is the water contact angle test result of unmodified 13X molecular sieve;
[0023] Figure 2 This is a graph showing the water contact angle test results of the hydrophobic zeolite molecular sieve prepared in Example 2;
[0024] Figure 3 This is a graph showing the water contact angle test results of the hydrophobic zeolite molecular sieve prepared in Example 1;
[0025] Figure 4 This is a graph showing the water contact angle test results of the hydrophobic zeolite molecular sieve prepared in Example 3. DETAILED DESCRIPTION
[0026] The present invention provides a method for preparing a hydrophobic zeolite molecular sieve, comprising the following steps:
[0027] The 13X molecular sieve, the hydrophobic modifier and the organic solvent are mixed (referred to as the first mixing) for grafting reaction and then activated to obtain the hydrophobic zeolite molecular sieve; the hydrophobic modifier includes siloxane.
[0028] The present invention mixes 13X molecular sieve, hydrophobic modifier and organic solvent for grafting reaction. In the present invention, the 13X molecular sieve is preferably dried before use, the drying temperature is preferably 300°C, the rate of heating to the drying temperature is preferably 8-10°C / min, specifically 9°C / min, the final temperature constant time is preferably 6-8h, specifically 7h; the drying atmosphere is preferably air; the drying equipment is preferably a muffle furnace. The present invention is dried under the above conditions, which is conducive to retaining the silanol groups on the surface of the zeolite.
[0029] In the present invention, the 13X molecular sieve is preferably soaked in water before drying and then solid-liquid separation is performed; the water is preferably distilled water or deionized water; the soaking time is preferably 10 to 60 minutes, specifically 20 minutes, 35 minutes or 50 minutes; the solid-liquid separation is preferably suction filtration. The present invention protects the hydroxyl groups on the surface of the zeolite molecular sieve by soaking.
[0030] In the present invention, the siloxane preferably includes one or more of hexyltrimethoxysilane, propyltrimethoxysilane and dodecyltrimethoxysilane. The siloxane used in the present invention has a similar pore size to that of the 13X molecular sieve, which is beneficial to the hydrophobicity of the pores of the 13X molecular sieve.
[0031] In the present invention, the ratio of the mass of the 13X molecular sieve to the total volume of the hydrophobic modifier and the organic solvent is preferably (0.5-5) g:100 mL, specifically 1 g:100 mL.
[0032] In the present invention, the organic solvent is preferably a benzene homologue; and the benzene homologue is preferably toluene.
[0033] In the present invention, the first mixing is preferably: premixing the hydrophobic modifier and the organic solvent to obtain a modified liquid, and second mixing the modified liquid and the 13X molecular sieve.
[0034] In the present invention, the concentration of the modified liquid is preferably 10-40 mmol / L, and specifically may be 20 mmol / L.
[0035] In the present invention, the second mixing is preferably stirring after ultrasound; the stirring speed is preferably 500 rpm. In the present invention, the 13X molecular sieve is fully contacted with the hydrophobic modifier through mixing, and the hydrophobic modifier is grafted onto the surface of the 13X molecular sieve.
[0036] In the present invention, the temperature of the grafting reaction is preferably 20-40°C, specifically 30°C, and the isothermal reaction time is preferably 24-36h, specifically 28h or 32h. The method provided by the present invention has mild synthesis conditions, and by controlling the reaction conditions, it is beneficial for the hydrophobic modifier to be evenly distributed in the pores without causing pore blockage.
[0037] After the grafting reaction, the present invention activates the obtained reaction product to obtain the hydrophobic zeolite molecular sieve. In the present invention, the reaction product is preferably filtered and washed before the activation; the filtering and washing is preferably washed after vacuum filtration; the reagent used for the washing is preferably alcohol; the alcohol is preferably ethanol; the number of washings is preferably 3 times.
[0038] In the present invention, the activation temperature is preferably 80-100° C., specifically 90° C., and the constant temperature activation time is preferably 24-36 h, specifically 27 h or 32 h.
[0039] The present invention also provides a hydrophobic zeolite molecular sieve obtained by the preparation method described in the above scheme, comprising a 13X molecular sieve and a hydrophobic carbon layer coated on the surface of the 13X molecular sieve; the component of the hydrophobic carbon layer comprises siloxane.
[0040] In the present invention, the siloxane preferably includes one or more of hexyltrimethoxysilane, propyltrimethoxysilane and dodecyltrimethoxysilane; the mass ratio of the hydrophobic carbon layer to the 13X molecular sieve is preferably 3-5:95-97, specifically 3:97.
[0041] In the present invention, the particle size of the hydrophobic zeolite molecular sieve is preferably 1 to 3 μm, specifically 2 μm.
[0042] The present invention also provides the hydrophobic zeolite molecular sieve in the above scheme in flue gas CO 2 Capture applications.
[0043] The hydrophobic zeolite molecular sieve provided by the present invention is subjected to simulated flue gas conditions (41°C, H 2 O / CO 2 / N 2 =7 / 13 / 80 gas mixture) shows good CO 2 Adsorption performance and cycle stability.
[0044] In the present invention, it is preferred to use a numerical calculation method of water vapor partial pressure to accurately control the water content in the mixed gas to achieve the purpose of simulating industrial flue gas.
[0045] The hydrophobic zeolite molecular sieve provided by the present invention has high adsorption efficiency and good stability, and is suitable for flue gas CO 2 Capture, especially suitable for CO22 Capture breaks the traditional use of zeolite molecular sieves for CO 2 Capture technology bottleneck.
[0046] In order to further illustrate the present invention, the scheme of the present invention is described in detail below in conjunction with the accompanying drawings and examples, but they should not be understood as limiting the scope of protection of the present invention. Unless otherwise specified, the reagents and equipment of the present invention are commercially available.
[0047] Example 1
[0048] Weigh 1g of 13X molecular sieve, soak the 13X molecular sieve in water for 10min, then place it in a muffle furnace, heat it to 300℃ at 10℃ / min, maintain it for 6h, and then cool it down naturally. Add 0.412g of hexyltrimethoxysilane to the toluene solution to prepare a 100mL solution with a concentration of 20mmol / L. Add the prepared solution to a sealed polypropylene bottle, and then add the above-mentioned dried 13X molecular sieve; use ultrasonic dispersion to disperse the 13X molecular sieve for 30min to form a translucent solution; then stir at room temperature for 24h at a speed of 500rpm; after the reaction is completed, vacuum filter the unreacted solvent and solute, then rinse with ethanol 3 times, and put the filtered product into a drying oven at 80℃ for 12h to obtain a hydrophobic zeolite molecular sieve.
[0049] Example 2
[0050] Weigh 1g of 13X molecular sieve, soak the 13X molecular sieve in water for 10min, then place it in a muffle furnace, heat it to 300℃ at 10℃ / min, maintain it for 6h, and then cool it down naturally. Add 0.328g of propyltrimethoxysilane to the toluene solution to prepare a 100mL solution with a concentration of 20mmol / L. Add the prepared solution to a sealed polypropylene bottle, and then add the above-mentioned dried 13X molecular sieve; use ultrasonic dispersion to disperse the 13X molecular sieve for 30min to form a translucent solution; then stir at room temperature for 24h at a speed of 500rpm; after the reaction is completed, vacuum filter the unreacted solvent and solute, then rinse with ethanol 3 times, and put the filtered product into a drying oven at 80℃ for 12h to obtain a hydrophobic zeolite molecular sieve.
[0051] Example 3
[0052] Weigh 1g of 13X molecular sieve, soak the 13X molecular sieve in water for 10min, then place it in a muffle furnace, heat it to 300℃ at 10℃ / min, maintain it for 6h, and then cool it down naturally. Add 0.692g of dodecyltrimethoxysilane to the toluene solution to prepare a 100mL solution with a concentration of 20mmol / L. Add the prepared solution to a sealed polypropylene bottle, and then add the above-mentioned dried 13X molecular sieve; use ultrasonic dispersion to disperse the 13X molecular sieve for 30min to form a translucent solution; then stir at room temperature for 24h at a speed of 500rpm; after the reaction is completed, vacuum filter the unreacted solvent and solute, then rinse with ethanol 3 times, and put the filtered product into a drying oven at 80℃ for 12h to obtain a hydrophobic zeolite molecular sieve.
[0053] Example 4
[0054] Weigh 1g of 13X molecular sieve, soak the 13X molecular sieve in water for 10min, then place it in a muffle furnace, heat it to 300℃ at 10℃ / min, maintain it for 6h, and then cool it down naturally. Add 0.206g of hexyltrimethoxysilane to the toluene solution to prepare a 100mL solution with a concentration of 20mmol / L. Add the prepared solution to a sealed polypropylene bottle, and then add the above-mentioned dried 13X molecular sieve; use ultrasonic dispersion to disperse the 13X molecular sieve for 30min to form a translucent solution; then stir at room temperature for 24h at a speed of 500rpm; after the reaction is completed, vacuum filter the unreacted solvent and solute, then rinse with ethanol 3 times, and put the filtered product into a drying oven at 80℃ for 12h to obtain a hydrophobic zeolite molecular sieve.
[0055] Example 5
[0056] Weigh 1g of 13X molecular sieve, soak the 13X molecular sieve in water for 10min, then place it in a muffle furnace, heat it to 300℃ at 10℃ / min, maintain it for 6h, and then cool it naturally. Add 0.848g of hexyltrimethoxysilane to the toluene solution to prepare a 100mL solution with a concentration of 20mmol / L. Add the prepared solution to a sealed polypropylene bottle, and then add the above-mentioned dried 13X molecular sieve; use ultrasonic dispersion to disperse the 13X molecular sieve for 30min to form a translucent solution; then stir at room temperature for 24h at a speed of 500rpm; after the reaction is completed, vacuum filter the unreacted solvent and solute, then rinse with ethanol 3 times, and put the filtered product into a drying oven at 80℃ for 12h to obtain a hydrophobic zeolite molecular sieve.
[0057] Comparative Example 1
[0058] Weigh 1g of 13X molecular sieve, soak the 13X molecular sieve in water for 10min, then place it in a muffle furnace, heat it to 300℃ at 10℃ / min, maintain it for 6h, and then cool it down naturally. Add 100mL of toluene solution into a sealed polypropylene bottle, and then add the above-mentioned dried 13X molecular sieve; disperse the 13X molecular sieve by ultrasonic dispersion for 30min to form a translucent solution; then stir at room temperature for 24h at a speed of 500rpm; after the reaction is completed, vacuum filter the unreacted solvent and solute, then rinse with ethanol 3 times, and put the filtered product into a drying oven at 80℃ for 12h to obtain a hydrophobic zeolite molecular sieve.
[0059] Test Example 1
[0060] The water contact angle test was performed on the hydrophobic zeolite molecular sieves prepared in Examples 1 to 3 and the unmodified 13X molecular sieve by using a contact angle tester (SDC 350KS). The static water contact angles of the four materials described above were tested to quantitatively characterize the hydrophilicity / hydrophobicity of their surfaces. The results are shown in FIG. Figures 1 to 4 As shown. Figures 1 to 4 It can be seen that the unmodified zeolite shows a contact angle of 15°, the water contact angle of the hydrophobic zeolite molecular sieve in Example 2 is 107°, the water contact angle of the hydrophobic zeolite molecular sieve in Example 1 is 158°, and the water contact angle of the hydrophobic zeolite molecular sieve in Example 3 is 146°. Compared with the unmodified 13X molecular sieve, the hydrophobic performance of the hydrophobic zeolite molecular sieve prepared by the present invention is greatly improved.
[0061] Test Example 2
[0062] The hydrophobic zeolite molecular sieves of Examples 1 to 5 and Comparative Example 1 were subjected to CO 2 Dynamic adsorption test, the test method is: configure volume ratio H 2 O / CO 2 / N 2 =7 / 13 / 80 41 ℃ mixed gas as simulated flue gas, the flow rate of simulated flue gas is 30sccm, the hydrophobic zeolite molecular sieve is filled into the adsorption column, and the CO in the outlet exhaust gas is detected by an online mass spectrometer detector (BSD-MS). 2 The concentration of CO 2 The adsorption capacity of the samples was tested and the test results are shown in Table 1.
[0063] Table 1 Examples 1 to 5 and Comparative Example 1 Hydrophobic zeolite molecular sieve CO 2 Adsorption results
[0064]
[0065]
[0066] It can be seen from Table 1 that the hydrophobic zeolite molecular sieve of Example 1 of the present invention still maintains a high CO 2 The adsorption amount shows that it has good hydrophobic properties; its change in dry and water-containing flue gas is small, indicating that it has high water stability.
[0067] It can be seen from the above examples that the hydrophobic zeolite molecular sieve prepared in the present invention retains the good adsorption performance of the 13X molecular sieve, enhances the hydrophobicity of the 13X molecular sieve pores, and solves the problem of decreased adsorption performance of traditional zeolite molecular sieves in water-containing flue gas.
[0068] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A method for preparing a hydrophobic zeolite molecular sieve, characterized in that: The following steps are involved: The 13X molecular sieve, a hydrophobic modifier and an organic solvent are mixed for grafting reaction and then activated to obtain the hydrophobic zeolite molecular sieve; the hydrophobic modifier includes siloxane.
2. The preparation method according to claim 1, characterized in that: The 13X molecular sieve is dried before use, the drying temperature is 300° C., the rate of heating to the drying temperature is 8-10° C. / min, and the final temperature constant temperature time is 6-8h.
3. The preparation method according to claim 2, characterized in that: The 13X molecular sieve is soaked in water before drying and then solid-liquid separation is performed; the soaking time is 10 to 60 minutes.
4. The preparation method according to claim 1, characterized in that: The temperature of the grafting reaction is 20-40° C., and the constant temperature reaction time is 24-36 hours.
5. The preparation method according to claim 1 or 4, characterized in that: The activation temperature is 80-100° C., and the constant temperature activation time is 24-36 hours.
6. The hydrophobic zeolite molecular sieve obtained by the preparation method according to any one of claims 1 to 5, characterized in that: The invention comprises a 13X molecular sieve and a hydrophobic carbon layer coated on the surface of the 13X molecular sieve; the components of the hydrophobic carbon layer include siloxane.
7. The hydrophobic zeolite molecular sieve according to claim 6, characterized in that: The siloxane includes one or more of hexyltrimethoxysilane, propyltrimethoxysilane and dodecyltrimethoxysilane.
8. The hydrophobic zeolite molecular sieve according to claim 6, characterized in that: The mass ratio of the hydrophobic carbon layer to the 13X molecular sieve is 3-5:95-97.
9. The hydrophobic zeolite molecular sieve according to claim 6 or 7, characterized in that: The particle size of the hydrophobic zeolite molecular sieve is 1 to 3 μm.
10. Use of the hydrophobic zeolite molecular sieve according to any one of claims 6 to 9 in capturing CO2 from flue gas.