Monatomic catalytic filter material with denitration function and preparation method thereof
The single-atom catalytic filter prepared by auxiliary reduction method solves the problem of high cost of removing nitrogen oxides and precious metal catalysts in flue gas in the prior art, and achieves the goal of efficient low-temperature denitrification effect and reducing catalyst costs.
Patent Information
- Application Number
- CN202411909896.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-04-11
AI Technical Summary
The existing industrial dust removal technology is difficult to effectively remove nitrogen oxides in flue gas, and precious metal-based catalysts have high cost problems in low-temperature activity.
Single-atom catalytic filter material with denitrification function was prepared by auxiliary reduction method. By soaking the filter material in lanthanum, cerium or praseodymium solution, subsequently baking and ascorbic acid treatment, finally loading the active metal to achieve low-temperature denitrification.
The specific activity of non-precious metals is improved, the amount of precious metals is reduced, and the low-temperature NH3-SCR effect is achieved. In the process of denitrification, the carbon monoxide in the flue gas is partially removed.
Smart Images
Figure CN119793070A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of industrial dust removal, and in particular relates to a single-atom catalytic filter material with a denitration function and a preparation method thereof. Background Art
[0002] At present, bag filters used in industrial dust removal mainly use filter bags for dust purification. Most filter bags are mainly used to filter dust particles, with the goal of achieving dust emission concentrations that meet national standards. However, with the advancement of environmental protection regulations, in addition to filtering dust particles, it is also necessary to control harmful gases in smoke, especially to remove nitrogen oxides. Nitrogen oxides are still one of the main pollutants causing environmental pollution. They can directly or indirectly lead to atmospheric problems such as photochemical smog, acid rain, greenhouse effect, and ozone hole. Nitrogen oxides in industrial smoke come from thermal power plants, steel, cement, and chemicals.
[0003] Application to NH 3 There are many types of catalysts for CO-SCR, among which non-precious metal-based catalysts are low-cost and widely used. Among the catalysts used in CO-SCR, precious metal-based catalysts have better low-temperature activity, but their cost is relatively high due to their high loading capacity.
[0004] Generally, the catalyst is loaded on the filter material by direct impregnation, that is, the cleaned filter material is immersed in a prepared precursor solution of a certain concentration, and then taken out for high-temperature baking after a certain temperature and time. The auxiliary reduction method is a method of loading the filter material with rare earth metal oxide carriers (lanthanum, cerium, praseodymium, etc.), and then loading single-atom dispersed active metals. The rare earth metal oxide is pretreated with ascorbic acid to form a structure that disperses the active metal at the atomic level, thereby achieving the purpose of improving the catalytic activity of the active metal or reducing the metal loading. Single-atom catalysts are a new type of catalytic material. Experimental and theoretical studies have shown that this type of material has special catalytic properties and shows excellent industrial application potential. It has made significant discoveries in the fields of electrocatalysis, photocatalysis and traditional thermal catalysis. However, there are few reports on the preparation of low-temperature denitrification catalysts with single-atom catalysts as the core, and there is no suitable technology to successfully apply it to composite filter materials with denitrification function. Summary of the invention
[0005] The main purpose of the present invention is to provide a single-atom catalytic filter material with denitration function and a preparation method thereof, so as to solve the problems existing in the prior art and use the single-atom catalytic material as the functional bearer of low-temperature denitration: on the one hand, the specific activity of non-precious metals can be improved, and the filter material has good low-temperature NH 3 -SCR effect; on the other hand, it can reduce the amount of precious metals used, so that the filter material does not need to use ammonia as a reducing agent during denitrification, and partially remove carbon monoxide in the flue gas.
[0006] In order to achieve the above object, one of the solutions of the present invention is: A method for preparing a single-atom catalytic filter material with a denitrification function, based on an auxiliary reduction method, comprises: (1) soaking the cut filter material in a first solution of 100-800 g / L, ultrasonicating for 1-12 h, and squeezing out the excess first solution to obtain a first filter material; the first solution is one of lanthanum nitrate, cerium nitrate, and praseodymium nitrate; (2) The first filter material is dried naturally, and then placed in an oven at 200-300°C for 2-8 hours to obtain a unit area loading of 50-200 g / m 2 The second filter material; (3) After cooling, soak the second filter material in a second solution with a concentration of 1 to 10 g / L for 1 to 12 hours, wash it three times, and place it in a vacuum drying oven at 60 to 120° C. for 2 to 8 hours to remove excess second solution, thereby obtaining a third filter material; the second solution is one of ascorbic acid, resorcinol, and m-phenylenediamine; (4) 0.01-5 wt % of active metal is loaded on the third filter material, and the precursor solution is impregnated into the third filter material using an equal volume impregnation method.
[0007] The material of the filter material is PI.
[0008] In the above (3), washing is performed using one of methanol, ethanol and isopropanol.
[0009] In the above (4), the active metal is one of platinum, rhodium, palladium, copper, iron, manganese, vanadium and molybdenum.
[0010] In the above (4), the precursor is one of chloride, nitrate and acetate.
[0011] The second solution of the present invention is: A single-atom catalytic filter material with a denitration function is prepared using the method for preparing the single-atom catalytic filter material with a denitration function.
[0012] After adopting the above technical solution, the present invention has the following technical effects: ① In terms of structure, the active metal in the single-atom catalytic filter material of the present invention is dispersed at the atomic level, while the existing denitration composite filter materials are all metal oxide catalysts dispersed in granular form.
[0013] ② In terms of function, the present invention greatly improves the utilization rate and specific activity of active metals (including non-precious metals and precious metals), reduces the dosage of active metals and the cost of catalysts (especially precious metals). In addition, the precious metal denitrification filter material can utilize CO in the flue gas for denitrification without the use of additional reducing agents; while the existing denitrification composite filter materials generally can only use NH3 as a reducing agent, and the required reaction temperature is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 This is an appearance diagram of a single-atom catalytic filter material prepared according to a specific embodiment of the present invention.
[0015] Figure 2 This is a microstructure diagram of a single-atom catalytic filter material prepared according to a specific embodiment of the present invention.
[0016] Figure 3 It is a device diagram of a tubular SCR reactor according to a specific embodiment of the present invention. DETAILED DESCRIPTION
[0017] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.
[0018] refer to Figure 1-3 As shown, the present invention discloses a method for preparing a single-atom catalytic filter material with a denitration function, based on an auxiliary reduction method, comprising the following preparation steps: (1) Cut the PI filter material into circular slices (diameter 8.7 cm, area 59.4 cm 2 , mass 3.0g) was immersed in 300g / L cerium nitrate solution, ultrasonicated for 2h, and the excess solution was squeezed out; (2) The filter material obtained in (1) was naturally dried and then placed in an oven for 4 h at 250°C to obtain a cerium oxide loading per unit area of about 100 g / m 2 CeO 2 / PI filter material; (3) After cooling, the obtained CeO was soaked in a 4 g / L ascorbic acid solution. 2 / PI filter material for 4 hours, washed with ethanol three times, and placed in a vacuum drying oven at 80°C for 4 hours to remove excess ascorbic acid on the surface of cerium oxide; (4) Based on the mass of cerium oxide, 0.01~5wt% of active metal (one of platinum, rhodium, palladium, copper, iron, manganese, vanadium, and molybdenum) is loaded, and the precursor (one of chloride, nitrate, and acetate) solution is impregnated into CeO using an equal volume impregnation method. 2 / PI filter material.
[0019] Taking 1% copper loading as an example, 0.0127 g of anhydrous copper chloride was dispersed in 11 mL of ethanol, and CeO pretreated with ascorbic acid was added. 2 / PI was placed in a 90 mm culture dish, and the copper chloride ethanol solution was evenly added to the CeO 2 / PI surface, ultrasonicated for 20 minutes, left to stand for 12 hours, and baked at 300℃ for 2 hours. The obtained catalytic filter material is in a state of single atom dispersion when the active metal loading is low, and in a state of coexistence of single atoms and metal oxide nanoparticles when the loading is high.
[0020] The appearance of the prepared single-atom catalytic filter material is as follows: Figure 1 Its microstructure is shown in Figure 2 shown.
[0021] The prepared single atom catalytic filter material is placed in Figure 3 The test was carried out in the tubular SCR reactor shown: The test device mainly includes steel cylinders of various gases, one-way valves, mass flow meters, stop valves, tubular heating furnaces, tubular reactors (including temperature control equipment such as thermocouples), exhaust gas treatment devices, etc. The exhaust gas pipeline is connected with a tee and a stop valve, and is connected to a flue gas analyzer; denitrification filter material is placed in the tubular reactor.
[0022] In the test gas entering the tubular SCR reactor, NO and NH 3 The volume fraction of O is 0.05%. 2 The volume fraction is 5%, the volume fraction of sulfur dioxide is 0.01%, and the rest is N 2 , gas flow rate is 400 mL min -1 After the airflow stabilized for 30 minutes, the concentration of inlet and outlet nitrogen oxides was measured using a Laoying 3012H-D portable flue gas analyzer to calculate the denitrification rate of the catalytic composite filter material.
[0023] When the reaction temperature is set to 200 °C, 1%Cu / CeO 2 The denitrification rate of / PI is 91%.
[0024] Modify the test conditions. When the volume fraction of NO in the test gas is 0.05%, the volume fraction of CO is 0.2%, and the rest is N 2 , gas flow rate is 400 mL min -1 , when the reaction temperature is set to 200℃, 0.05%Rh / CeO 2 The denitrification rate of / PI is 95%.
[0025] In addition, the dust removal performance of the prepared single-atom catalytic filter material is 99.99%.
[0026] Through the above scheme, in terms of structure, the active metal in the single-atom catalytic filter material of the present invention is dispersed at the atomic level, while the existing denitration composite filter materials are all metal oxide catalysts, which are dispersed in granular form; in terms of function, the present invention greatly improves the utilization rate and specific activity of active metals (including non-precious metals and precious metals), reduces the amount of active metals and the catalyst cost (especially precious metals), and in addition, the precious metal denitration filter material can utilize CO in the flue gas for denitration without using an additional reducing agent; while the existing denitration composite filter materials generally can only use NH 3 As a reducing agent, the required reaction temperature is relatively high.
[0027] The above embodiments and drawings do not limit the product form and style of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.
Claims
1. A method for preparing a single-atom catalytic filter material with denitrification function, based on an auxiliary reduction method, characterized in that include: (1) soaking the cut filter material in a first solution of 100-800 g / L, ultrasonicating for 1-12 h, and squeezing out the excess first solution to obtain a first filter material; the first solution is one of lanthanum nitrate, cerium nitrate, and praseodymium nitrate; (2) The first filter material is dried naturally, and then placed in an oven at 200-300°C for 2-8 hours to obtain a unit area loading of 50-200 g / m 2 The second filter material; (3) After cooling, soak the second filter material in a second solution with a concentration of 1 to 10 g / L for 1 to 12 hours, wash it three times, and place it in a vacuum drying oven at 60 to 120° C. to dry it for 2 to 8 hours to remove excess second solution, thereby obtaining a third filter material; The second solution is one of ascorbic acid, resorcinol, and m-phenylenediamine; (4) 0.01-5 wt % of active metal is loaded on the third filter material, and the precursor solution is impregnated into the third filter material using an equal volume impregnation method.
2. The method for preparing the single-atom catalytic filter material with denitration function according to claim 1, characterized in that: The material of the filter material is PI.
3. The method for preparing the single-atom catalytic filter material with denitration function according to claim 1, characterized in that: In the above (3), washing is performed using one of methanol, ethanol and isopropanol.
4. The method for preparing a single-atom catalytic filter material with a denitration function according to claim 1, characterized in that: In the above (4), the active metal is one of platinum, rhodium, palladium, copper, iron, manganese, vanadium and molybdenum.
5. The method for preparing a single-atom catalytic filter material with a denitration function according to claim 1, characterized in that: In the above (4), the precursor is one of chloride, nitrate and acetate.
6. A single-atom catalytic filter material with denitration function, characterized in that The method for preparing the single-atom catalytic filter material with denitration function as claimed in any one of claims 1 to 5 is used to prepare the single-atom catalytic filter material.