A filter bag loaded with a denitration catalyst and a preparation method thereof

Abstract

The application relates to the field of filtering materials, and discloses a filter bag loaded with a denitration catalyst and a preparation method thereof, the filter bag comprising interface modifier impregnated modified polytetrafluoroethylene fibers and a catalytic additive loaded on the modified polytetrafluoroethylene fibers, the interface modifier being prepared by hydrolysis-polycondensation of tetraethyl orthosilicate, perfluorooctyl ethyl trimethyl silane, trimethyl borate and 3-(2,3-epoxypropoxy) propyl trimethyl silane; the catalytic additive is a hollow spherical catalyst carrier prepared by emulsion-induced interface assembly using polyether Pluronic F127, 1,3,5-trimethylbenzene and dopamine as raw materials and by externally introducing mesoporous silica, then precursors of cerium and manganese are loaded on the surface of the hollow spherical catalyst carrier and a titanium dioxide shell layer is coated to prepare the catalytic additive; the filter bag prepared by the application has good denitration activity, sulfur resistance, water resistance, hydrophobicity and friction resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of filter materials, and particularly relates to a filter bag loaded with a denitration catalyst and a preparation method thereof. BACKGROUND

[0002] Industrial exhaust gas contains solid particles and toxic gas components, which not only destroy the ecological environment, but also seriously affect human health. The filter bag dust collector is currently recognized as one of the most effective technologies and equipment in treating the tail gas of a power plant. The polytetrafluoroethylene filter material has excellent properties such as high temperature resistance, acid and alkali resistance, hydrolysis resistance, and high flame resistance, and thus becomes the first choice for a coal-fired boiler and a waste incinerator filter bag. However, the polytetrafluoroethylene filter material has poor wear resistance. The denitration functional filter material refers to a filter material loaded with a denitration catalyst on the surface of the filter material fiber, so as to have the dual functions of dust removal and denitration.

[0003] NOx is an atmospheric pollutant that directly threatens the ecological environment and human health, and mainly comes from the fuel combustion process in fixed sources such as coal-fired power plants, coking plants, and industrial boilers. The ammonia selective catalytic reduction method is the most widely used NOx removal technology in industry, and the catalyst is the core of the technology. The V-Ti catalyst is the mainstream commercial catalyst in coal-fired power plants at home and abroad, and exhibits excellent denitration performance at medium and high temperatures (> 300 ℃). However, the traditional V-Ti catalyst has poor low-temperature activity, a narrow effective temperature window, and certain environmental toxicity, which limits its further development. The manganese-based catalyst has attracted widespread attention due to its strong low-temperature activity and rich valence state changes of Mn metal. However, the manganese-based catalyst with a single active component has poor stability and resistance to water and SO2. SUMMARY

[0004] To solve the problems mentioned in the background, the purpose of the present application is to provide a filter bag loaded with a denitration catalyst and a preparation method thereof. The prepared filter bag has good NOx catalytic removal performance, can maintain a NOx conversion rate of more than 85% and a N2 yield at 180-220 ℃, and has good water and sulfur resistance, hydrophobicity, and abrasion resistance.

[0005] The purpose of the present application can be achieved by the following technical solutions.

[0006] The filter bag loaded with a denitration catalyst comprises modified polytetrafluoroethylene fibers and a catalytic additive loaded on the modified polytetrafluoroethylene fibers. The modified polytetrafluoroethylene fibers are prepared by immersing polytetrafluoroethylene fibers in an interface modifier and then taking them out and drying. The interface modifier is prepared by hydrolysis-polycondensation reaction using tetraethyl orthosilicate, perfluorooctyl ethyl trimethoxysilane, trimethyl borate, and 3-(2,3-epoxypropoxy) propyl trimethoxysilane as raw materials.

[0007] The catalytic additive is a hollow spherical catalyst carrier prepared by emulsion-induced interface assembly using polyether Pluronic F127 as a template agent, 1,3,5-trimethylbenzene as a pore swelling and interface modifier, dopamine as a carbon source and nitrogen source, and then further using a sol-gel method by externally introducing mesoporous silica to prepare the hollow spherical catalyst carrier, and then loading precursors of cerium and manganese onto the surface of the hollow spherical catalyst carrier and using a coprecipitation method to prepare a titanium dioxide shell layer to make.

[0008] Preferably, the preparation method of the interface modifier comprises the following steps: mixing deionized water, hydrochloric acid and isopropanol uniformly to obtain solution one, taking isopropanol, tetraethyl orthosilicate, perfluorooctyl ethyl trimethoxysilane, trimethyl borate and 3-(2,3-epoxypropoxy) propyl trimethoxysilane, heating to 50-60°C and keeping constant temperature, obtaining solution two, then slowly adding solution one to solution two within 1h, after the addition is completed, heating to 75-85°C, refluxing for 20-24h, after the reaction is completed, cooling to 45-55°C, adding sodium bicarbonate and stirring for 0.5-1h, and finally filtering to obtain the interface modifier.

[0009] Preferably, the molar ratio of the tetraethyl orthosilicate, perfluorooctyl ethyl trimethoxysilane, trimethyl borate and 3-(2,3-epoxypropoxy) propyl trimethoxysilane is 1.2-1.3:3.8-3.9:1-1.8:5-5.3.

[0010] Preferably, the preparation method of the catalytic additive comprises the following steps:

[0011] (1) taking polyether F127 and hydrochloric acid dopamine and dispersing them in a reactor containing a mixed solution of anhydrous ethanol and distilled water, adding 1,3,5-trimethylbenzene and then uniformly dispersing under ultrasonic condition at room temperature, after the ultrasonic dispersion is completed, placing the solution at 30-35°C and stirring to form a uniform emulsion, then adding concentrated ammonia water drop by drop and continuing to stir for 7-9h, then adding cetyltrimethylammonium bromide and stirring for 20-30min, then adding tetraethyl orthosilicate and continuously stirring for 4-4.5h, after the reaction is completed, centrifuging, washing and drying, grinding the dried solid, and then placing it in a tube furnace in a nitrogen atmosphere for high-temperature calcination to prepare the hollow spherical catalyst carrier;

[0012] (2) The hollow spherical catalyst carrier is taken and dispersed in anhydrous ethanol, and cerium nitrate hexahydrate and manganese acetate tetrahydrate are added and stirred to mix uniformly, and then magnetic stirring is performed at room temperature for 3.5-4.5 h, and then the ethanol is removed by rotary evaporation, and the dried solid is ground and dispersed in anhydrous ethanol by ultrasonic dispersion to obtain a suspension, and the suspension is stirred in a water bath at 55-65℃, and ammonia water and titania sulfate solution are simultaneously and slowly added to the suspension until the pH value is 9-11, and after the reaction is completed, the solid is filtered, washed and dried, and then the dried solid is ground and placed in a tube furnace in a hydrogen-argon mixed gas atmosphere for high-temperature reduction to prepare the catalytic additive.

[0013] Preferably, the addition ratio of polyether F127, dopamine hydrochloride, anhydrous ethanol, distilled water, 1,3,5-trimethylbenzene, concentrated ammonia water, cetyltrimethylammonium bromide and tetraethyl orthosilicate in step (1) is 0.1 g:0.12 g:5 mL:5 mL:0.1 mL:0.08 mL:0.1 g:0.6 mL.

[0014] Preferably, the high-temperature calcination in step (1) is set as follows: the temperature is raised to 520-550℃ at a temperature raising rate of 2-4℃ / min, and maintained for 2-3 h to remove the template agent, and then the temperature is further raised to 820-850℃ at a temperature raising rate of 2-4℃ / min, and maintained for 2-3 h.

[0015] Preferably, the concentration of the titania sulfate solution in step (2) is 0.1-0.4 mol / L; and the addition ratio of the hollow spherical catalyst carrier, cerium nitrate hexahydrate, manganese acetate tetrahydrate and titania sulfate solution is 0.1 g:15-16 mg:48-49 mg:1-1.5 mL.

[0016] Preferably, in step (2), the volume fraction of hydrogen in the hydrogen-argon mixed gas atmosphere is 15%, and the volume fraction of argon is 85%; and the high-temperature reduction is set as follows: the temperature is raised to 520-550℃ at a temperature raising rate of 2-3℃ / min, and maintained for 4-5 h.

[0017] The preparation method of the filter bag loaded with the denitration catalyst as described above comprises the following steps:

[0018] S1, the catalytic additive is taken and dispersed in an aqueous acrylic resin, and then a PTFE emulsion binder is added, and mechanical stirring is performed for 30-40 min to form a well-dispersed mixed solution;

[0019] S2, the mixed solution containing the catalytic additive is deposited on the cut modified polytetrafluoroethylene fiber by the impregnation and rolling method, 1 rolling is performed after 1 impregnation, and then 175-190℃ setting is performed for 2-3 min, and 230-250℃ curing is performed for 2-3 min to prepare the filter bag loaded with the denitration catalyst.

[0020] The beneficial effects of the present application are:

[0021] The present application utilizes tetraethyl orthosilicate, perfluorooctyl ethyl trimethoxysilane, trimethyl borate and 3-(2,3-epoxypropoxy) propyl trimethoxysilane as raw materials to undergo hydrolysis-polycondensation reaction to prepare an interface modifier, then the interface modifier is used to impregnate polytetrafluoroethylene fibers to prepare modified polytetrafluoroethylene fibers, wherein 3-(2,3-epoxypropoxy) propyl trimethoxysilane is a reactive main chain to ensure the bonding force with the polytetrafluoroethylene fibers, perfluorooctyl ethyl trimethoxysilane is a core functional group to provide super-hydrophobic properties, tetraethyl orthosilicate and trimethyl borate are auxiliary adjusting agents to optimize mechanical properties and thermal properties, and tetraethyl orthosilicate and trimethyl borate form a hard Si-O-Si and B-O-Si inorganic network with organic components to interweave into a dense hybrid coating, which significantly improves the wear resistance of the polytetrafluoroethylene fibers, and in addition, the epoxy groups introduced in the interface modifier can form covalent bond with the subsequent loaded catalytic additives, so that the catalytic additives can be firmly and durably loaded on the modified polytetrafluoroethylene fibers, avoiding the falling off of the catalytic additives in the process of airflow scouring and pulse ashing, greatly prolonging the service life of the filter bag.

[0022] The present application utilizes polyether Pluronic F127 as a template agent, 1,3,5-trimethylbenzene as a pore swelling and interface adjusting agent, and dopamine as a carbon source and nitrogen source to synthesize polydopamine spheres by emulsion-induced interface assembly, and further utilizes a sol-gel method to prepare a hollow spherical catalyst carrier with larger pore size and higher nitrogen content by externally introducing mesoporous silica, the larger pore size makes mass transfer more convenient, and the high nitrogen content promotes the anchoring of more dispersed active component metal nanoparticles, the manganese and cerium ions are fixed by metal-nitrogen coordination to prevent migration and agglomeration, thereby realizing high dispersion at the nanoscale, then the precursors of cerium and manganese are loaded on the large surface of the hollow spherical catalyst carrier, and a titanium dioxide shell coated catalytic additive is prepared by a coprecipitation method, the B acid sites and abundant L acid sites formed by the titanium dioxide shell increase the adsorption and activation of ammonia, the high-valence active component manganese ion and the high proportion of manganese ion and cerium ion ensure the activation rate of ammonia and nitric oxide, improve the low-temperature redox cycle efficiency of the catalyst, and inhibit the deep oxidation of sulfur dioxide, so that the catalytic additive exhibits excellent denitration activity and good sulfur and water resistance in a wide temperature range. DETAILED DESCRIPTION

[0023] With reference to the drawings and in light of the following description, the application will be better understood. Numerous specific details are set forth in order to provide a thorough understanding of the application. However, it will be apparent to one skilled in the art that the application can be practiced without the specific details given. In other instances, well-known methods have not been described in detail in order to avoid obscuring the application. The following description and examples provide specific details for a thorough understanding of, and enabling description for, embodiments of the application. One skilled in the art will understand that the application can be practiced without

[0024] The preparation method of the interface modifier of Example 1 comprises the following steps: uniformly mixing 28 mL of deionized water, 10 g of hydrochloric acid and 100 g of isopropyl alcohol to obtain solution one, heating 53 g of isopropyl alcohol, 7.5 g of tetraethyl orthosilicate, 62.5 g of perfluorooctyl ethyl trimethoxysilane, 4.2 g of trimethyl borate and 35.4 g of 3-(2,3-epoxypropoxy) propyl trimethoxysilane to 55°C and keeping constant temperature to obtain solution two, then slowly adding solution one into solution two within 1 h, increasing the temperature to 80°C after the addition is completed, refluxing for 24 h, decreasing the temperature to 50°C after the reaction is completed, adding 23 g of sodium bicarbonate and stirring for 1 h, and finally preparing the interface modifier through filtration.

[0025] The preparation method of the catalytic additive of Example 2 comprises the following steps:

[0026] (1) 0.1 g of polyether F127 and 0.12 g of dopamine hydrochloride are dispersed in a reactor containing 5 mL of anhydrous ethanol and 5 mL of distilled water mixed solution, 0.1 mL of 1,3,5-trimethylbenzene is added, and then ultrasonic dispersion is carried out uniformly at room temperature, after the ultrasonic dispersion is completed, the solution is placed at 30°C for stirring to form a uniform emulsion, 0.08 mL of concentrated ammonia is added dropwise, and stirring is continued for 8 h, then 0.1 g of cetyltrimethylammonium bromide is added and stirred for 25 min, 0.6 mL of tetraethyl orthosilicate is added, and stirring is continued for 4 h, after the reaction is completed, centrifugation, washing and drying are carried out, the dried solid is ground and placed in a tube furnace in a nitrogen atmosphere for high-temperature calcination, the temperature is increased to 550°C at a rate of 3°C / min, and kept for 2 h to remove the template, and then the temperature is further increased to 850°C at a rate of 3°C / min, and kept for 2 h, to prepare a hollow spherical catalyst carrier;

[0027] (2) 0.1 g of the hollow spherical catalyst carrier was dispersed in 25 mL of anhydrous ethanol, 15.3 mg of cerium nitrate hexahydrate and 48.3 mg of manganese acetate tetrahydrate were added and stirred to mix uniformly, then magnetic stirring was performed at room temperature for 4 h, and then the ethanol was removed by rotary evaporation, the dried solid was ground and dispersed in anhydrous ethanol by ultrasonic dispersion to obtain a suspension, and the suspension was stirred in a water bath at 60°C, ammonia water and 1.3 mL of titania sulfate solution with a concentration of 0.2 mol / L were simultaneously and slowly added to the suspension until the pH value was 10, after the reaction was completed, the solid was filtered, washed and dried, the dried solid was ground and placed in a tube furnace in a hydrogen (15%) -argon (85%) mixed gas atmosphere for high-temperature reduction, the temperature was increased to 550°C at a rate of 2°C / min and maintained for 4 h, and a catalytic additive was prepared.

[0028] Example 3 A preparation method of a catalytic additive includes the following steps:

[0029] (1) 0.1 g of polyether F127 and 0.12 g of dopamine hydrochloride were dispersed in a reactor containing 5 mL of a mixed solution of anhydrous ethanol and distilled water, 0.1 mL of 1,3,5-trimethylbenzene was added, and ultrasonic dispersion was performed at room temperature until uniform, the solution was then stirred at 30°C to form a uniform emulsion, 0.08 mL of concentrated ammonia water was added dropwise, and stirring was continued for 8 h, then 0.1 g of cetyltrimethylammonium bromide was added and stirred for 25 min, and then 0.6 mL of tetraethyl orthosilicate was added, and stirring was continued for 4 h, after the reaction was completed, the solid was centrifuged, washed and dried, the dried solid was ground and placed in a tube furnace in a nitrogen atmosphere for high-temperature calcination, the temperature was increased to 520°C at a rate of 2°C / min and maintained for 2 h to remove the template, and then the temperature was further increased to 820°C at a rate of 2°C / min and maintained for 2 h, and a hollow spherical catalyst carrier was prepared;

[0030] (2) 0.1 g of the hollow spherical catalyst carrier was dispersed in 25 mL of anhydrous ethanol, 15.6 mg of cerium nitrate hexahydrate and 48.5 mg of manganese acetate tetrahydrate were added and stirred to mix uniformly, then magnetic stirring was performed at room temperature for 4 h, and then the ethanol was removed by rotary evaporation, the dried solid was ground and dispersed in anhydrous ethanol by ultrasonic dispersion to obtain a suspension, and the suspension was stirred in a water bath at 60°C, ammonia water and 1.5 mL of titania sulfate solution with a concentration of 0.1 mol / L were simultaneously and slowly added to the suspension until the pH value was 10, after the reaction was completed, the solid was filtered, washed and dried, the dried solid was ground and placed in a tube furnace in a hydrogen (15%) -argon (85%) mixed gas atmosphere for high-temperature reduction, the temperature was increased to 520°C at a rate of 2°C / min and maintained for 5 h, and a catalytic additive was prepared.

[0031] Example 4 A preparation method of a catalytic additive includes the following steps:

[0032] (1) Take 0.1 g of polyether F127 and 0.12 g of dopamine hydrochloride and disperse them in a reactor containing a mixture of 5 mL of anhydrous ethanol and 5 mL of distilled water, add 0.1 mL of 1,3,5-trimethylbenzene, and then ultrasonically disperse them uniformly at room temperature. After the ultrasonic dispersion is completed, the solution is stirred at 30°C to form a uniform emulsion. Then, 0.08 mL of concentrated ammonia water is added dropwise, and the stirring is continued for 8 h. Then, 0.1 g of cetyltrimethylammonium bromide is added and stirred for 25 min. Then, 0.6 mL of tetraethyl orthosilicate is added, and the stirring is continued for 4 h. After the reaction is completed, the product is centrifuged, washed, and dried. The dried solid is ground and then placed in a tube furnace under a nitrogen atmosphere for high-temperature calcination. The temperature is raised to 530°C at a rate of 3°C / min and maintained for 2 h to remove the template. Then, the temperature is further raised to 840°C at a rate of 3°C / min and maintained for 2 h to prepare a hollow spherical catalyst carrier;

[0033] (2) Take 0.1 g of the hollow spherical catalyst carrier and disperse it in 25 mL of anhydrous ethanol. Add 16 mg of cerium nitrate hexahydrate and 49 mg of manganese acetate tetrahydrate, and stir to mix uniformly. Then, magnetically stir at room temperature for 4 h. Then, remove the ethanol by rotary evaporation. The dried solid is ground and then ultrasonically dispersed in anhydrous ethanol to obtain a suspension. The suspension is stirred in a water bath at 60°C. Simultaneously, ammonia water and 1.5 mL of a titania sulfate solution with a concentration of 0.3 mol / L are slowly added dropwise to the suspension until the pH value reaches 10. After the reaction is completed, the product is filtered, washed, and dried. The dried solid is ground and then placed in a tube furnace under a hydrogen (15%)-argon (85%) mixed gas atmosphere for high-temperature reduction. The temperature is raised to 540°C at a rate of 3°C / min and maintained for 5 h to prepare a catalytic additive.

[0034] Example 5 A method for preparing a filter bag loaded with a denitration catalyst, comprising the following steps:

[0035] S1, take 10 g of the catalytic additive prepared in Example 2 and disperse it in 20 g of an aqueous acrylic resin. Then, add 30 g of a PTFE emulsion binder (solid content 18%) and mechanically stir for 35 min to form a well-dispersed mixture. Dip the polytetrafluoroethylene fibers in the interfacial modifier prepared in Example 1 and dry them to obtain modified polytetrafluoroethylene fibers.

[0036] S2, deposit the mixture containing the catalytic additive on the cut modified polytetrafluoroethylene fibers by the impregnation-calendering method. Perform 1 impregnation and 1 calendering, then set the temperature to 180°C and fix for 2 min, and then set the temperature to 240°C and cure for 3 min to prepare a filter bag loaded with a denitration catalyst.

[0037] Example 6 A preparation method of a filter bag loaded with a denitration catalyst, compared with Example 5, the catalytic additive prepared in Example 2 is replaced with an equal amount of the catalytic additive prepared in Example 3, and the preparation method of the remaining components is the same as that in Example 5.

[0038] Example 7 A preparation method of a filter bag loaded with a denitration catalyst, compared with Example 5, the catalytic additive prepared in Example 2 is replaced with an equal amount of the catalytic additive prepared in Example 4, and the preparation method of the remaining components is the same as that in Example 5.

[0039] Comparative Example 1 A preparation method of a catalytic additive includes the following steps:

[0040] (1) 0.1 g of polyether F127 and 0.12 g of dopamine hydrochloride were dispersed in a reactor containing 5 mL of anhydrous ethanol and 5 mL of a mixed solution of distilled water, 0.1 mL of 1,3,5-trimethylbenzene was added, and the solution was uniformly dispersed under ultrasonic dispersion at room temperature. After ultrasonic dispersion, the solution was placed in a 30°C water bath for stirring to form a uniform emulsion. Then 0.08 mL of concentrated ammonia was added dropwise and stirring was continued for 8 h. Then 0.1 g of cetyltrimethylammonium bromide was added and stirred for 25 min. Then 0.6 mL of tetraethyl orthosilicate was added, and stirring was continued for 4 h. After the reaction was completed, the solid was centrifuged, washed, and dried. The dried solid was ground and placed in a tube furnace under a nitrogen atmosphere for high-temperature calcination. The temperature was raised to 550°C at a rate of 3°C / min and maintained for 2 h to remove the template. Further, the temperature was raised to 850°C at a rate of 3°C / min and maintained for 2 h to prepare a hollow spherical catalyst carrier.

[0041] (2) 0.1 g of the hollow spherical catalyst carrier was dispersed in 25 mL of anhydrous ethanol, 15.3 mg of cerium nitrate hexahydrate and 48.3 mg of manganese acetate tetrahydrate were added and stirred to mix uniformly. Then, magnetic stirring was carried out at room temperature for 4 h. Subsequently, the ethanol was removed by rotary evaporation, and the dried solid was ground and placed in a tube furnace under a hydrogen (15%) -argon (85%) mixed gas atmosphere for high-temperature reduction. The temperature was raised to 550°C at a rate of 2°C / min and maintained for 4 h to prepare a catalytic additive.

[0042] Comparative Example 2 A preparation method of a catalytic additive includes the following steps:

[0043] Take 15.3 mg of cerium nitrate hexahydrate, 48.3 mg of manganese acetate tetrahydrate, 25 mL of deionized water, stir and mix uniformly, add ammonia water dropwise to pH 10, water bath heating and stirring, aging, then filter, wash, dry, and grind the dried solid. Ultrasonic dispersion in anhydrous ethanol to obtain a suspension, and place it in a 60°C water bath under stirring. Slowly add ammonia water and 1.3 mL of 0.2 mol / L titania sulfate solution to the suspension simultaneously until the pH is 10. After the reaction is completed, filter, wash, and dry. Grind the dried solid and place it in a hydrogen (15%) -argon (85%) mixed gas atmosphere tube furnace for high temperature reduction. Increase the temperature to 550°C at a rate of 2°C / min and maintain for 4 h to prepare the catalytic additive.

[0044] Comparative Example 3: A method for preparing a filter bag loaded with a denitration catalyst, compared with Example 5, the catalytic additive prepared in Example 2 is replaced with an equal amount of the catalytic additive prepared in Comparative Example 1, and the preparation method of the remaining components is the same as that in Example 5.

[0045] Comparative Example 4: A method for preparing a filter bag loaded with a denitration catalyst, compared with Example 5, the catalytic additive prepared in Example 2 is replaced with an equal amount of the catalytic additive prepared in Comparative Example 2, and the preparation method of the remaining components is the same as that in Example 5.

[0046] Comparative Example 5: A method for preparing a filter bag loaded with a denitration catalyst, compared with Example 5, the modified polytetrafluoroethylene fiber in step S2 is replaced with an equal amount of polytetrafluoroethylene fiber, which is not impregnated with an interfacial modifier for modification, and the preparation method of the remaining components is the same as that in Example 5.

[0047] Performance detection

[0048] The filter bags prepared in Examples 5-7 and Comparative Examples 3-5 were subjected to performance detection:

[0049] (1) Water contact angle: The static water contact angle of the sample was measured using a DSA30 type contact angle measuring instrument, and the test results are shown in Table 1.

[0050] (2) Rubbing resistance: According to GB 3960-83 standard, the rubbing and wear resistance of the sample was determined on a MM-200 type rubbing and wear tester, and the test results are shown in Table 1.

[0051] (3) Denitration performance: NH3-SCR performance test was carried out under the conditions of 8% O2, 1000 ppm NH3, 1000 ppm NO, and gas velocity 0.8 m / min, and the test results are shown in Table 1.

[0052] (4) Water and sulfur resistance: The NOx conversion of the catalytic filter material was measured at 200℃ for 6h by introducing 200ppm SO2 and 10% H2O into the reaction gas, and the test results are shown in Table 1.

[0053] Table 1 Test results of sample performance

[0054]

[0055] As can be seen from the data in Table 1, the filter bags prepared in Examples 5-7 have good NOx catalytic removal performance, and can maintain a NOx conversion rate of more than 85% and a N2 yield at 180-220℃, while having good water and sulfur resistance, hydrophobicity and abrasion resistance. The catalytic additive added in Comparative Example 3 does not form a titanium dioxide shell layer, and the catalytic additive added in Comparative Example 4 does not introduce a hollow spherical catalyst carrier, and the measured NOx conversion rate and N2 yield, water and sulfur resistance of Comparative Examples 3-4 are lower than those of Examples 5-7, which shows that the catalytic additive formed by the titanium dioxide shell layer and the hollow spherical catalyst carrier can synergistically improve the denitration activity and sulfur and water resistance of the material. In Comparative Example 5, polytetrafluoroethylene fibers are not impregnated and modified by the interfacial modifier, and the water contact angle and abrasion resistance grade are lower than those of Examples 5-7, which shows that the introduction of the interfacial modifier is beneficial to improving the hydrophobicity and abrasion resistance of the material.

[0056] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0057] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only illustrative of the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A filter bag loaded with a de-NOx catalyst, characterized by, The application relates to a modified polytetrafluoroethylene fiber and a catalytic additive loaded on the modified polytetrafluoroethylene fiber, wherein the modified polytetrafluoroethylene fiber is prepared by immersing a polytetrafluoroethylene fiber in an interface modifier and taking out and drying; the interface modifier is prepared by hydrolysis-polycondensation reaction with tetraethyl orthosilicate, perfluorooctyl ethyl trimethoxysilane, trimethyl borate and 3-(2,3-epoxypropoxy) propyl trimethoxysilane as raw materials; The catalytic additive is prepared by emulsion-induced interface assembly with polyether Pluronic F127 as a template agent, 1,3,5-trimethylbenzene as a pore swelling and interface adjusting agent and dopamine as a carbon source and nitrogen source to synthesize polydopamine balls, and then by a sol-gel method, a hollow spherical catalyst carrier is prepared by externally introducing mesoporous silica, and then a precursor of cerium and manganese is loaded on the surface of the hollow spherical catalyst carrier and a titanium dioxide shell layer is prepared by a coprecipitation method. The preparation method of the interface modifier comprises the following steps: mixing deionized water, hydrochloric acid and isopropyl alcohol uniformly to obtain solution one, adding isopropyl alcohol, tetraethyl orthosilicate, perfluorooctyl ethyl trimethoxysilane, trimethyl borate and 3-(2,3-epoxypropoxy) propyl trimethoxysilane, heating to 50-60 DEG C and keeping constant temperature to obtain solution two, then slowly dropping solution one into solution two within 1h, increasing the temperature to 75-85 DEG C, refluxing for 20-24h, decreasing the temperature to 45-55 DEG C, adding sodium bicarbonate and stirring for 0.5-1h, and finally filtering to obtain the interface modifier. The preparation method of the catalytic additive comprises the following steps: (1) dispersing polyether F127 and dopamine hydrochloride in a reactor containing a mixed solution of anhydrous ethanol and distilled water, adding 1,3,5-trimethylbenzene and uniformly dispersing under ultrasonic condition at room temperature, placing the solution in a 30-35 DEG C water bath after ultrasonic treatment to form a uniform emulsion, continuously adding concentrated ammonia water and stirring for 7-9h, then adding cetyltrimethylammonium bromide and stirring for 20-30min, adding tetraethyl orthosilicate and continuously stirring for 4-4.5h, centrifuging, washing and drying the solid after reaction, grinding the dried solid, placing the solid in a nitrogen atmosphere tube furnace for high-temperature calcination to obtain a hollow spherical catalyst carrier; (2) dispersing the hollow spherical catalyst carrier in anhydrous ethanol, adding cerium nitrate hexahydrate and manganese acetate tetrahydrate, stirring and mixing uniformly, magnetically stirring at room temperature for 3.5-4.5h, removing ethanol by rotary evaporation, grinding the dried solid, ultrasonically dispersing the solid in anhydrous ethanol to obtain a suspension, placing the suspension in a 55-65 DEG C water bath and stirring, slowly dropping ammonia water and titania sulfate solution into the suspension until the pH value is 9-11, filtering, washing and drying the solid after reaction, grinding the dried solid, placing the solid in a hydrogen-argon mixed gas atmosphere tube furnace for high-temperature reduction to obtain the catalytic additive.

2. The load de-NOx catalyst-equipped filter bag according to claim 1, characterized by, The molar ratio of the tetraethyl orthosilicate, perfluorooctyl ethyl trimethoxysilane, trimethyl borate and 3-(2,3-epoxypropoxy) propyl trimethoxysilane is 1.2-1.3:3.8-3.9:1-1.8:5-5.

3.

3. The load de-NOx catalysted filter bag according to claim 1, characterized by, The adding ratio of the polyether F127, dopamine hydrochloride, anhydrous ethanol, distilled water, 1,3,5-trimethylbenzene, concentrated ammonia, cetyltrimethylammonium bromide and tetraethyl orthosilicate in step (1) is 0.1 g:0.12 g:5 mL:5 mL:0.1 mL:0.08 mL:0.1 g:0.6 mL.

4. The load de-NOx catalysted filter bag of claim 1, wherein, The high-temperature calcination in step (1) is set as follows: the temperature is raised to 520-550 ℃ at a temperature raising rate of 2-4 ℃ / min, and maintained for 2-3 h to remove the template agent, and then the temperature is further raised to 820-850 ℃ at a temperature raising rate of 2-4 ℃ / min, and maintained for 2-3 h.

5. The load deNOx catalysted filter bag of claim 1, wherein, The concentration of the titanyl sulfate solution in step (2) is 0.1-0.4 mol / L; and the adding ratio of the hollow spherical catalyst carrier, cerium nitrate hexahydrate, manganese acetate tetrahydrate and the titanyl sulfate solution is 0.1 g:15-16 mg:48-49 mg:1-1.5 mL.

6. The load deNOx catalysted filter bag of claim 1, wherein, The volume fraction of hydrogen in the hydrogen-argon mixed gas atmosphere in step (2) is 15%, and the volume fraction of argon is 85%; and the high-temperature reduction is set as follows: the temperature is raised to 520-550 ℃ at a temperature raising rate of 2-3 ℃ / min, and maintained for 4-5 h.

7. The method of producing a filter bag loaded with a denitration catalyst according to any one of claims 1 to 6, characterized by, The method comprises the following steps: S1, dispersing the catalytic additive in the aqueous acrylic resin, then adding the PTFE emulsion binder, and mechanically stirring for 30-40 min to form a well-dispersed mixed solution; S2, depositing the mixed solution containing the catalytic additive on the cut modified polytetrafluoroethylene fiber by the dip-rolling method, rolling once after 1-time dipping, then setting at 175-190 ℃ for 2-3 min, and curing at 230-250 ℃ for 2-3 min to prepare a filter bag loaded with the denitration catalyst.

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