Composite MOFs catalyst for waste gas treatment and preparation method thereof
By preparing composite MOF catalysts and combining them with copper-cerium composite materials, the problem of poor VOCs removal efficiency in waste gas treatment in existing technologies has been solved, achieving a highly efficient waste gas treatment effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-04-07
AI Technical Summary
Existing technologies are insufficient for efficiently removing volatile organic compounds (VOCs) from waste gases, especially in industrial coating and chemical production, where the application of MOF catalysts is not ideal.
A composite MOF catalyst preparation method is adopted, which involves ball milling, drying, calcination and other steps, combined with copper-cerium composite catalytic materials to form a MOF catalyst with a highly ordered pore structure. The synergistic effect of copper and cerium is utilized to achieve efficient adsorption and catalytic decomposition of VOCs.
It significantly improves the adsorption and catalytic decomposition efficiency of VOCs in waste gas, achieving high efficiency and environmental protection in waste gas treatment and reducing environmental pollution.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of waste gas treatment technology, specifically a composite MOF catalyst for waste gas treatment and its preparation method. Background Technology
[0002] With the accelerating pace of global industrialization, environmental problems caused by waste gas emissions are becoming increasingly severe, making waste gas treatment a critical issue that urgently needs to be addressed. Among these, the harm of volatile organic compounds (VOCs) to the ecological environment and human health cannot be ignored, necessitating effective measures to strengthen the control and treatment of VOC emissions. Metal-organic frameworks (MOFs), as a novel type of catalyst, have demonstrated undeniable modern value in the field of waste gas treatment. MOF catalysts possess ultra-high specific surface area and abundant porous structures, enabling them to efficiently adsorb and catalytically decompose harmful substances in waste gases, such as volatile organic compounds (VOCs) and nitrogen oxides (NOx). x This helps to significantly reduce the pollution of the atmospheric environment by exhaust gases, reduce environmental problems such as smog and acid rain, and protect the ecological balance and human living environment. For example, in the treatment of exhaust gases in industries such as industrial coating and chemical production, MOF catalysts can effectively remove harmful components from exhaust gases, enabling the emitted gases to meet environmental protection standards.
[0003] To overcome the shortcomings of the prior art, the present invention provides a composite MOF catalyst for waste gas treatment and its preparation method. Summary of the Invention
[0004] The purpose of this invention is to provide a composite MOF catalyst for waste gas treatment and its preparation method, so as to solve the problems raised in the prior art.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] A method for preparing a composite MOF catalyst for waste gas treatment includes the following steps:
[0007] Step 1: Mix copper oxide and cerium acetate and ball mill them. After ball milling, dry and calcine the powder to obtain copper-cerium composite catalyst.
[0008] Step 2: Mix the MOF catalyst and the copper-cerium composite catalyst and ball mill them. After ball milling, the mixture is sieved and washed to obtain the composite MOF catalyst.
[0009] In a more optimized manner, in step one, the cerium content in the copper-cerium composite catalyst is 55-60 wt%, and the copper content is 10-12 wt%; the ball milling speed is 450-550 r / min, and the ball milling time is 4-5 h; the drying temperature is 110-125 ℃, and the drying time is 3.5-4.5 h; the calcination temperature is 500-550 ℃, and the calcination time is 3-4 h.
[0010] In a more optimized manner, in step two, the mixing ratio of MOF catalyst and copper-cerium composite catalyst is (1.2-1.5):1; the ball milling speed is 180-200 r / min, and the ball milling time is 1.5-2.5 h.
[0011] A more optimized preparation process for MOF catalysts is as follows:
[0012] Step S1: Add anhydrous sodium metasilicate and sodium hydroxide to deionized water, stir and dissolve to obtain a reaction solution; add sodium aluminate to deionized water, stir and dissolve to obtain a sodium aluminate solution; mix the reaction solution and sodium aluminate solution, stir evenly, and then perform a hydrothermal reaction at 100-110℃ for 3.5-4.0h. After the reaction is completed, cool, filter, wash and dry to obtain molecular sieve material.
[0013] Step S2: Place the molecular sieve material in a nitrogen atmosphere, add toluene, stir evenly, add γ-aminopropyltriethoxysilane, and react at 105-110℃ for 1.5-1.8h. After the reaction is completed, cool, wash and dry to obtain the modified molecular sieve material.
[0014] Step S3: Add copper nitrate to deionized water, stir evenly, adjust the pH of the solution to 3-4, then add modified molecular sieve material, stir at 25-30℃ for 5-8 min to obtain modified solution; then add 1,3,5-benzenetricarboxylic acid to deionized water, stir evenly to obtain 1,3,5-benzenetricarboxylic acid dispersion; then mix the modified solution and the 1,3,5-benzenetricarboxylic acid dispersion, react at 70-75℃ for 15-20 h, after the reaction is completed, cool, filter, wash and dry to obtain MOF catalyst.
[0015] In a more optimized manner, in step S1, the mass ratio of anhydrous sodium metasilicate, sodium hydroxide, and deionized water is (8.5-9.0):2:45; the mass ratio of sodium aluminate and deionized water is (6.5-7.0):40; and the mass ratio of sodium hydroxide and sodium aluminate is 2:(6.5-7.0).
[0016] In a more optimized manner, in step S2, the mass-to-volume ratio of the molecular sieve material, γ-aminopropyltriethoxysilane, and toluene is 2g:(0.12-0.15)mL:100mL.
[0017] In a more optimized manner, in step S3, the reaction mass ratio of copper nitrate, modified molecular sieve material, and 1,3,5-benzenetricarboxylic acid is 5:(0.6-0.8):2.5.
[0018] The beneficial effects of this invention are:
[0019] The key feature of this invention is that in step S1, anhydrous sodium metasilicate, sodium hydroxide, and sodium aluminate are the key raw materials for synthesizing the molecular sieve material. Anhydrous sodium metasilicate provides the silicon source, and sodium aluminate provides the aluminum source. Under the alkaline environment created by sodium hydroxide, the silicon and aluminum sources undergo a chemical reaction, forming a molecular sieve material with a regular pore structure through a hydrothermal reaction. This molecular sieve material has a large specific surface area and abundant microporous structure, providing numerous adsorption sites for the adsorption of volatile organic compounds (VOCs) in waste gas. The microporous structure of the molecular sieve has a certain degree of matching with the size of VOC molecules, enabling the capture of VOC molecules in waste gas within the pores through physical adsorption.
[0020] Furthermore, in step S2, the molecular sieve material is modified using γ-aminopropyltriethoxysilane. Then, copper nitrate, the modified molecular sieve material, and 1,3,5-benzenetricarboxylic acid are mixed to obtain the MOF catalyst. When amino groups are present on the molecular sieve surface, coordination occurs between the amino groups and the MOF precursor solution formed by adding copper nitrate and 1,3,5-benzenetricarboxylic acid. That is, the metal ions in the MOF precursor solution form stable coordination compounds with the amino groups. This coordination allows the amino groups to participate in the formation of the MOF catalyst, thereby growing MOF structures on the modified molecular sieve surface. MOFs possess a highly ordered pore structure and a large specific surface area, further increasing the number of adsorption sites.
[0021] Furthermore, by adding copper oxide and cerium acetate as raw materials, and then ball-milling, drying, and calcining, a copper-cerium composite catalyst was obtained. The MOF catalyst and the copper-cerium composite catalyst were then mixed, ball-milled, sieved, and washed to obtain a composite MOF catalyst. In the copper-cerium composite catalyst, there is a significant synergistic effect between copper and cerium. Cerium's oxygen storage and release capabilities can provide sufficient oxygen for the copper redox cycle, promoting the rapid conversion of copper ions between different oxidation states, thereby accelerating the oxidative decomposition reaction of VOCs. When VOC molecules are adsorbed onto the surface of the composite MOF catalyst, copper ions first interact with the VOC molecules, partially oxidizing them through a redox reaction, while cerium promptly provides oxygen species, allowing the reaction to continue. Simultaneously, the presence of copper can also affect the electronic structure and redox performance of cerium, further improving its oxygen storage capacity and catalytic activity.
[0022] Furthermore, this invention sets the mixing ratio of MOF catalyst and copper-cerium composite catalyst to (1.2-1.5):1. Within this ratio range, the synergistic effect between the MOF catalyst and the copper-cerium composite catalyst can be fully utilized. The MOF catalyst has a large specific surface area and abundant porous structure, enabling it to efficiently adsorb VOC molecules in waste gas and enrich them on the catalyst surface. In the copper-cerium composite catalyst, there is a significant synergistic effect between copper and cerium. The oxygen storage and release capacity of cerium provides sufficient oxygen for the copper redox cycle, promoting the rapid conversion of copper ions between different oxidation states and accelerating the oxidative decomposition reaction of VOCs. When the two are mixed at (1.2-1.5):1, the VOCs adsorbed by the MOF catalyst can be promptly decomposed by the copper-cerium composite catalyst, achieving a highly efficient combination of adsorption and catalysis. Detailed Implementation
[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] Example 1: Step S1: Anhydrous sodium metasilicate and sodium hydroxide were added to deionized water and stirred to dissolve, resulting in a reaction solution; sodium aluminate was added to deionized water and stirred to dissolve, resulting in a sodium aluminate solution; the reaction solution and sodium aluminate solution were mixed and stirred evenly, and then subjected to hydrothermal reaction at 110℃ for 4.0 h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain molecular sieve material; the mass ratio of anhydrous sodium metasilicate, sodium hydroxide, and deionized water was 8.7:2:45; the mass ratio of sodium aluminate and deionized water was 6.7:40; and the mass ratio of sodium hydroxide and sodium aluminate was 2:6.7.
[0025] Step S2: Place the molecular sieve material in a nitrogen atmosphere, add toluene, stir evenly, then add γ-aminopropyltriethoxysilane, and react at 110℃ for 1.8h. After the reaction is completed, cool, wash, and dry to obtain the modified molecular sieve material; the mass-volume ratio of molecular sieve material, γ-aminopropyltriethoxysilane, and toluene is 2g:0.13mL:100mL.
[0026] Step S3: Add copper nitrate to deionized water, stir until homogeneous, adjust the pH of the solution to 4, then add modified molecular sieve material, stir at 30℃ for 8 min to obtain a modified solution; then add 1,3,5-benzenetricarboxylic acid to deionized water, stir until homogeneous to obtain a 1,3,5-benzenetricarboxylic acid dispersion; then mix the modified solution and the 1,3,5-benzenetricarboxylic acid dispersion, react at 75℃ for 20 h, after the reaction is completed, cool, filter, wash, and dry to obtain the MOF catalyst; the reaction mass ratio of copper nitrate, modified molecular sieve material, and 1,3,5-benzenetricarboxylic acid is 5:0.7:2.5;
[0027] Step S4: Mix copper oxide and cerium acetate, and ball mill at 500 r / min for 5 h. After ball milling, dry the powder at 125℃ for 4.5 h and calcine at 550℃ for 4 h to obtain copper-cerium composite catalyst material; the cerium content in the copper-cerium composite catalyst material is 57 wt%, and the copper content is 11 wt%.
[0028] Step S5: Mix the MOFs catalyst and the copper-cerium composite catalyst and ball mill at 190 r / min for 2.5 h. After ball milling, the mixture is sieved and washed to obtain the composite MOFs catalyst. The mixing ratio of the MOFs catalyst and the copper-cerium composite catalyst is 1.3:1.
[0029] Example 2: Step S1: Anhydrous sodium metasilicate and sodium hydroxide were added to deionized water and stirred to dissolve, resulting in a reaction solution; sodium aluminate was added to deionized water and stirred to dissolve, resulting in a sodium aluminate solution; the reaction solution and sodium aluminate solution were mixed and stirred evenly, and then subjected to hydrothermal reaction at 105℃ for 3.7h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain molecular sieve material; the mass ratio of anhydrous sodium metasilicate, sodium hydroxide, and deionized water was 8.7:2:45; the mass ratio of sodium aluminate and deionized water was 6.7:40; and the mass ratio of sodium hydroxide and sodium aluminate was 2:6.7.
[0030] Step S2: Place the molecular sieve material in a nitrogen atmosphere, add toluene, stir evenly, then add γ-aminopropyltriethoxysilane, and react at 107℃ for 1.6h. After the reaction is completed, cool, wash, and dry to obtain the modified molecular sieve material; the mass-volume ratio of molecular sieve material, γ-aminopropyltriethoxysilane, and toluene is 2g:0.13mL:100mL.
[0031] Step S3: Add copper nitrate to deionized water, stir until homogeneous, adjust the pH of the solution to 3.5, then add modified molecular sieve material, stir at 27℃ for 7 min to obtain a modified solution; then add 1,3,5-benzenetricarboxylic acid to deionized water, stir until homogeneous to obtain a 1,3,5-benzenetricarboxylic acid dispersion; then mix the modified solution and the 1,3,5-benzenetricarboxylic acid dispersion, react at 73℃ for 17 h, after the reaction is completed, cool, filter, wash, and dry to obtain the MOF catalyst; the reaction mass ratio of copper nitrate, modified molecular sieve material, and 1,3,5-benzenetricarboxylic acid is 5:0.7:2.5;
[0032] Step S4: Mix copper oxide and cerium acetate, and ball mill at 500 r / min for 4.5 h. After ball milling, dry the powder at 115℃ for 4 h and calcine at 525℃ for 3.5 h to obtain copper-cerium composite catalyst material; the cerium content in the copper-cerium composite catalyst material is 57 wt%, and the copper content is 11 wt%.
[0033] Step S5: Mix the MOFs catalyst and the copper-cerium composite catalyst material, and ball mill at 190 r / min for 2 h. After ball milling, the mixture is sieved and washed to obtain the composite MOFs catalyst. The mixing ratio of MOFs catalyst and copper-cerium composite catalyst material is 1.3:1.
[0034] Example 3: Step S1: Anhydrous sodium metasilicate and sodium hydroxide were added to deionized water and stirred to dissolve, resulting in a reaction solution; sodium aluminate was added to deionized water and stirred to dissolve, resulting in a sodium aluminate solution; the reaction solution and sodium aluminate solution were mixed and stirred evenly, and then subjected to hydrothermal reaction at 100°C for 3.5 hours. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain molecular sieve material; the mass ratio of anhydrous sodium metasilicate, sodium hydroxide, and deionized water was 8.7:2:45; the mass ratio of sodium aluminate and deionized water was 6.7:40; and the mass ratio of sodium hydroxide and sodium aluminate was 2:6.7.
[0035] Step S2: Place the molecular sieve material in a nitrogen atmosphere, add toluene, stir evenly, then add γ-aminopropyltriethoxysilane, and react at 105℃ for 1.5h. After the reaction is completed, cool, wash, and dry to obtain the modified molecular sieve material; the mass-volume ratio of molecular sieve material, γ-aminopropyltriethoxysilane, and toluene is 2g:0.13mL:100mL.
[0036] Step S3: Add copper nitrate to deionized water, stir evenly, adjust the pH of the solution to 3, then add modified molecular sieve material, stir at 25℃ for 5 min to obtain a modified solution; then add 1,3,5-benzenetricarboxylic acid to deionized water, stir evenly to obtain a 1,3,5-benzenetricarboxylic acid dispersion; then mix the modified solution and the 1,3,5-benzenetricarboxylic acid dispersion, react at 70℃ for 15 h, after the reaction is completed, cool, filter, wash and dry to obtain the MOF catalyst; the reaction mass ratio of copper nitrate, modified molecular sieve material and 1,3,5-benzenetricarboxylic acid is 5:0.7:2.5;
[0037] Step S4: Mix copper oxide and cerium acetate, and ball mill at 500 r / min for 4 h. After ball milling, dry the powder at 110℃ for 3.5 h and calcine at 500℃ for 3 h to obtain copper-cerium composite catalyst material; the cerium content in the copper-cerium composite catalyst material is 57 wt%, and the copper content is 11 wt%.
[0038] Step S5: Mix the MOFs catalyst and the copper-cerium composite catalyst and ball mill at 190 r / min for 1.5 h. After ball milling, the mixture is sieved and washed to obtain the composite MOFs catalyst. The mixing ratio of the MOFs catalyst and the copper-cerium composite catalyst is 1.3:1.
[0039] Comparative Example 1: The copper-cerium composite catalyst material was removed, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Anhydrous sodium metasilicate and sodium hydroxide were added to deionized water and stirred to dissolve to obtain a reaction solution; sodium aluminate was added to deionized water and stirred to dissolve to obtain a sodium aluminate solution; the reaction solution and sodium aluminate solution were mixed and stirred evenly, and then hydrothermally reacted at 110℃ for 4.0 h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain the molecular sieve material; the mass ratio of anhydrous sodium metasilicate, sodium hydroxide, and deionized water was 8.7:2:45; the mass ratio of sodium aluminate and deionized water was 6.7:40; and the mass ratio of sodium hydroxide and sodium aluminate was 2:6.7.
[0040] Step S2: Place the molecular sieve material in a nitrogen atmosphere, add toluene, stir evenly, then add γ-aminopropyltriethoxysilane, and react at 110℃ for 1.8h. After the reaction is completed, cool, wash, and dry to obtain the modified molecular sieve material; the mass-volume ratio of molecular sieve material, γ-aminopropyltriethoxysilane, and toluene is 2g:0.13mL:100mL.
[0041] Step S3: Add copper nitrate to deionized water, stir evenly, adjust the pH of the solution to 4, then add modified molecular sieve material, stir at 30℃ for 8 min to obtain modified solution; then add 1,3,5-benzenetricarboxylic acid to deionized water, stir evenly to obtain 1,3,5-benzenetricarboxylic acid dispersion; then mix the modified solution and 1,3,5-benzenetricarboxylic acid dispersion, react at 75℃ for 20 h, after the reaction is completed, cool, filter, wash and dry to obtain MOF catalyst; the reaction mass ratio of copper nitrate, modified molecular sieve material and 1,3,5-benzenetricarboxylic acid is 5:0.7:2.5.
[0042] Comparative Example 2: The mixing ratio of MOF catalyst and copper-cerium composite catalyst was adjusted to 0.5:1, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Anhydrous sodium metasilicate and sodium hydroxide were added to deionized water and stirred to dissolve to obtain a reaction solution; sodium aluminate was added to deionized water and stirred to dissolve to obtain a sodium aluminate solution; the reaction solution and sodium aluminate solution were mixed and stirred evenly, and then hydrothermally reacted at 110℃ for 4.0h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain molecular sieve material; the mass ratio of anhydrous sodium metasilicate, sodium hydroxide, and deionized water was 8.7:2:45; the mass ratio of sodium aluminate and deionized water was 6.7:40; and the mass ratio of sodium hydroxide and sodium aluminate was 2:6.7.
[0043] Step S2: Place the molecular sieve material in a nitrogen atmosphere, add toluene, stir evenly, then add γ-aminopropyltriethoxysilane, and react at 110℃ for 1.8h. After the reaction is completed, cool, wash, and dry to obtain the modified molecular sieve material; the mass-volume ratio of molecular sieve material, γ-aminopropyltriethoxysilane, and toluene is 2g:0.13mL:100mL.
[0044] Step S3: Add copper nitrate to deionized water, stir until homogeneous, adjust the pH of the solution to 4, then add modified molecular sieve material, stir at 30℃ for 8 min to obtain a modified solution; then add 1,3,5-benzenetricarboxylic acid to deionized water, stir until homogeneous to obtain a 1,3,5-benzenetricarboxylic acid dispersion; then mix the modified solution and the 1,3,5-benzenetricarboxylic acid dispersion, react at 75℃ for 20 h, after the reaction is completed, cool, filter, wash, and dry to obtain the MOF catalyst; the reaction mass ratio of copper nitrate, modified molecular sieve material, and 1,3,5-benzenetricarboxylic acid is 5:0.7:2.5;
[0045] Step S4: Mix copper oxide and cerium acetate, and ball mill at 500 r / min for 5 h. After ball milling, dry the powder at 125℃ for 4.5 h and calcine at 550℃ for 4 h to obtain copper-cerium composite catalyst material; the cerium content in the copper-cerium composite catalyst material is 57 wt%, and the copper content is 11 wt%.
[0046] Step S5: Mix the MOF catalyst and the copper-cerium composite catalyst and ball mill at 190 r / min for 2.5 h. After ball milling, the mixture is sieved and washed to obtain the composite MOF catalyst. The mixing ratio of the MOF catalyst and the copper-cerium composite catalyst is 0.5:1.
[0047] Comparative Example 3: The mixing ratio of MOF catalyst and copper-cerium composite catalyst was adjusted to 2:1, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Anhydrous sodium metasilicate and sodium hydroxide were added to deionized water and stirred to dissolve to obtain a reaction solution; sodium aluminate was added to deionized water and stirred to dissolve to obtain a sodium aluminate solution; the reaction solution and sodium aluminate solution were mixed and stirred evenly, and then hydrothermally reacted at 110℃ for 4.0h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain molecular sieve material; the mass ratio of anhydrous sodium metasilicate, sodium hydroxide, and deionized water was 8.7:2:45; the mass ratio of sodium aluminate and deionized water was 6.7:40; and the mass ratio of sodium hydroxide and sodium aluminate was 2:6.7.
[0048] Step S2: Place the molecular sieve material in a nitrogen atmosphere, add toluene, stir evenly, then add γ-aminopropyltriethoxysilane, and react at 110℃ for 1.8h. After the reaction is completed, cool, wash, and dry to obtain the modified molecular sieve material; the mass-volume ratio of molecular sieve material, γ-aminopropyltriethoxysilane, and toluene is 2g:0.13mL:100mL.
[0049] Step S3: Add copper nitrate to deionized water, stir until homogeneous, adjust the pH of the solution to 4, then add modified molecular sieve material, stir at 30℃ for 8 min to obtain a modified solution; then add 1,3,5-benzenetricarboxylic acid to deionized water, stir until homogeneous to obtain a 1,3,5-benzenetricarboxylic acid dispersion; then mix the modified solution and the 1,3,5-benzenetricarboxylic acid dispersion, react at 75℃ for 20 h, after the reaction is completed, cool, filter, wash, and dry to obtain the MOF catalyst; the reaction mass ratio of copper nitrate, modified molecular sieve material, and 1,3,5-benzenetricarboxylic acid is 5:0.7:2.5;
[0050] Step S4: Mix copper oxide and cerium acetate, and ball mill at 500 r / min for 5 h. After ball milling, dry the powder at 125℃ for 4.5 h and calcine at 550℃ for 4 h to obtain copper-cerium composite catalyst material; the cerium content in the copper-cerium composite catalyst material is 57 wt%, and the copper content is 11 wt%.
[0051] Step S5: Mix the MOF catalyst and the copper-cerium composite catalyst and ball mill at 190 r / min for 2.5 h. After ball milling, the mixture is sieved and washed to obtain the composite MOF catalyst. The mixing ratio of the MOF catalyst and the copper-cerium composite catalyst is 2:1.
[0052] Testing and experimentation:
[0053] Adsorption test: A waste gas model gas (styrene content of 250 mg / m3) was used as the test waste gas. The catalyst prepared in Examples 1-3 of this invention was used as the sample. A 500 mL volume of the sample was placed in the adsorption tube. Under the conditions of 25°C and an inlet flow rate of 5 m3 / h, the waste gas model gas was introduced, and then nitrogen was introduced by opening the nitrogen valve. After adsorption treatment for 5 h, the styrene content was tested.
[0054] Catalytic performance test: A waste gas model gas (styrene content of 250 mg / m³) was used as the test waste gas. The catalysts prepared in Examples 1-3 of this invention were used as samples. 500 mL of the sample was placed in a fixed-bed reactor. The waste gas model gas was introduced at a temperature of 230°C and an inlet flow rate of 5 m³ / h. After 5 hours of catalytic reaction, the styrene content was tested. The results are shown in the table below:
[0055]
[0056] Conclusion: In Examples 1-3, the dosage remained unchanged, with only some reaction parameters modified. Experimental data showed no significant fluctuations in the performance of the samples.
[0057] Comparative Example 1: The copper-cerium composite catalyst was removed, and the rest was the same as in Example 1. The experimental data showed that, compared with Example 1, the styrene content increased to 84.6 mg / m3 after the catalytic test. The reason for this is that the copper-cerium composite catalyst has a good catalytic oxidation effect on volatile organic compounds such as styrene. Therefore, after removing it, the overall catalytic effect of the catalyst decreased significantly, resulting in an increase in the styrene content after the catalytic test.
[0058] Comparative Example 2: The mixing ratio of MOFs catalyst and copper-cerium composite catalyst was adjusted to 0.5:1, while the rest remained the same as in Example 1. Experimental data showed that, compared to Example 1, the styrene content increased to 138.5 mg / m³ after the adsorption test and to 3.4 mg / m³ after the catalytic test. The reason for this is that the mixing ratio of MOFs catalyst and copper-cerium composite catalyst in this invention is set to (1.2-1.5):1. This allows the VOCs adsorbed by the MOFs catalyst to be promptly decomposed by the copper-cerium composite catalyst, achieving a highly efficient combination of adsorption and catalysis. Therefore, after adjusting the amount of MOFs catalyst, the styrene content increased to 138.5 mg / m³ after the adsorption test and to 3.4 mg / m³ after the catalytic test.
[0059] Comparative Example 3: The mixing ratio of MOFs catalyst and copper-cerium composite catalyst was adjusted to 2:1, while the rest remained the same as in Example 1. Experimental data showed that, compared to Example 1, the styrene content increased to 98.4 mg / m³ after the adsorption test and increased to 2.4 mg / m³ after the catalytic test. The reason for this is that the mixing ratio of MOFs catalyst and copper-cerium composite catalyst in this invention is set to (1.2-1.5):1. This allows the VOCs adsorbed by the MOFs catalyst to be promptly decomposed by the copper-cerium composite catalyst, achieving a highly efficient combination of adsorption and catalysis. Therefore, after adjusting the amount of MOFs catalyst, the styrene content increased to 98.4 mg / m³ after the adsorption test and increased to 2.4 mg / m³ after the catalytic test.
[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process method article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process method article or apparatus.
[0061] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a composite MOF catalyst for waste gas treatment, characterized in that: Includes the following steps: Step 1: Mix copper oxide and cerium acetate and ball mill them. After ball milling, dry and calcine the powder to obtain copper-cerium composite catalyst. Step 2: Mix the MOF catalyst and the copper-cerium composite catalyst and ball mill them. After ball milling, the mixture is sieved and washed to obtain the composite MOF catalyst.
2. The method for preparing a composite MOF catalyst for waste gas treatment according to claim 1, characterized in that: In step one, the cerium content in the copper-cerium composite catalyst is 55-60 wt%, and the copper content is 10-12 wt%; the ball milling speed is 450-550 r / min, and the ball milling time is 4-5 h; the drying temperature is 110-125 ℃, and the drying time is 3.5-4.5 h; the calcination temperature is 500-550 ℃, and the calcination time is 3-4 h.
3. The method for preparing a composite MOF catalyst for waste gas treatment according to claim 1, characterized in that: In step two, the mixing ratio of MOF catalyst and copper-cerium composite catalyst is (1.2-1.5):1; the ball milling speed is 180-200 r / min, and the ball milling time is 1.5-2.5 h.
4. The method for preparing a composite MOF catalyst for waste gas treatment according to claim 1, characterized in that: The preparation process of MOF catalysts is as follows: Step S1: Add anhydrous sodium metasilicate and sodium hydroxide to deionized water, stir and dissolve to obtain a reaction solution; add sodium aluminate to deionized water, stir and dissolve to obtain a sodium aluminate solution; mix the reaction solution and sodium aluminate solution, stir evenly, and then perform a hydrothermal reaction at 100-110℃ for 3.5-4.0h. After the reaction is completed, cool, filter, wash and dry to obtain molecular sieve material. Step S2: Place the molecular sieve material in a nitrogen atmosphere, add toluene, stir evenly, add γ-aminopropyltriethoxysilane, and react at 105-110℃ for 1.5-1.8h. After the reaction is completed, cool, wash and dry to obtain the modified molecular sieve material. Step S3: Add copper nitrate to deionized water, stir evenly, adjust the pH of the solution to 3-4, then add modified molecular sieve material, stir at 25-30℃ for 5-8 min to obtain modified solution; then add 1,3,5-benzenetricarboxylic acid to deionized water, stir evenly to obtain 1,3,5-benzenetricarboxylic acid dispersion; then mix the modified solution and the 1,3,5-benzenetricarboxylic acid dispersion, react at 70-75℃ for 15-20 h, after the reaction is completed, cool, filter, wash and dry to obtain MOF catalyst.
5. The method for preparing a composite MOF catalyst for waste gas treatment according to claim 1, characterized in that: In step S1, the mass ratio of anhydrous sodium metasilicate, sodium hydroxide, and deionized water is (8.5-9.0):2:45; the mass ratio of sodium aluminate and deionized water is (6.5-7.0):40; and the mass ratio of sodium hydroxide and sodium aluminate is 2:(6.5-7.0).
6. The method for preparing a composite MOF catalyst for waste gas treatment according to claim 1, characterized in that: In step S2, the mass-to-volume ratio of molecular sieve material, γ-aminopropyltriethoxysilane, and toluene is 2g:(0.12-0.15)mL:100mL.
7. The method for preparing a composite MOF catalyst for waste gas treatment according to claim 1, characterized in that: In step S3, the mass ratio of copper nitrate, modified molecular sieve material, and 1,3,5-benzenetricarboxylic acid is 5:(0.6-0.8):2.
5.
8. A composite MOF catalyst for waste gas treatment, characterized in that, Prepared by the preparation method according to any one of claims 1-7.