A CO oxidation catalyst using waste rare earth-based denitrification catalyst as raw material and its preparation method

Abstract

The present invention discloses a CO oxidation catalyst using waste rare earth-based denitration catalyst as raw material and a preparation method thereof. The catalyst is prepared by compounding waste rare earth-based denitration catalyst, diatomaceous earth and kaolin to prepare the CO oxidation catalyst carrier, and copper manganese lanthanum composite oxide (CuMnLaO x ) is the catalytic active component. The waste rare earth-based denitrification catalyst, diatomaceous earth and kaolin are crushed, batched, calcined and other processes to prepare the carrier. CuMnLaO x The precursor is prepared into a colloidal solution, and then the support is impregnated with CuMnLaO x The precursor colloidal solution is dried and calcined to obtain a CO oxidation catalyst. The CO oxidation catalyst of the present invention not only completely solves the harmless disposal of spent rare earth-based denitrification catalysts, but also enables their high-value-added resource utilization for catalytic oxidation of CO. Its simple process, low cost, and excellent activity offer significant advantages in the field of catalytic CO oxidation.

Description

Technical Field

[0001] The present invention provides a CO oxidation catalyst using waste rare earth-based denitration catalyst as raw material and a preparation method thereof, belonging to the fields of waste product resource utilization, environmentally friendly catalytic materials and air pollution control, and is particularly suitable for low-temperature catalytic oxidation of CO. Background Art

[0002] Rare earth-based denitrification catalysts, primarily based on environmentally friendly rare earth cerium-based composite oxides as their primary active component, are the second industrial flue gas denitrification catalyst in the world to achieve large-scale application. However, their widespread use has led to a significant generation of discarded rare earth-based denitrification catalysts. Furthermore, the Environmental Protection Network has issued a "Notice on Strengthening the Supervision and Administration of Waste Flue Gas Denitrification Catalysts," which incorporates the management, regeneration, and utilization of waste flue gas denitrification catalysts into hazardous waste management and requires increased regeneration and disposal capabilities. Therefore, the regeneration and resource utilization of discarded rare earth-based denitrification catalysts has become an urgent environmental challenge.

[0003] With the continuous growth of coal, oil and natural gas production and their large-scale consumption, CO produced by incomplete combustion has gradually become one of the main air pollutants. When inhaled, CO can cause necrosis of body tissues due to lack of oxygen, and in severe cases, it may endanger human life. In addition, CO can also react with NO x , VOC, etc. produce photochemical reactions, causing damage to the ecological environment. The current methods for removing CO include adsorption, CO methanation and CO catalytic oxidation. Among them, CO catalytic oxidation technology has become the most important method and means for eliminating CO due to its simplicity, low cost and high efficiency. The core of this technology is the catalyst. Among the related technologies of existing CO oxidation catalysts, patents (CN202010194813.4, CN202210319520.3, CN202210222829.0) use precious metals as active components, which is too expensive. Patents (CN202210366374.X, CN201910543206.1, CN201811520481.3, CN201711349954.3) directly use active metals as carriers, or use composite oxides themselves as catalysts to catalyze the oxidation of CO. This method has low utilization rate of metal oxides, which limits the practical application of catalysts.

[0004] The main component of the waste rare earth-based denitration catalyst is a titanium dioxide support with a large specific surface area and good stability. Its main active component is an environmentally friendly rare earth cerium-based composite oxide. Cerium dioxide (CeO2) has a unique fluorite structure with high oxygen storage and release capacity and redox properties. The rich pore structure and large specific surface area of ​​diatomaceous earth can better disperse the active component. The addition of kaolin can improve the catalyst's molding and enhance its mechanical strength. Copper oxide and manganese oxide have excellent catalytic CO oxidation capabilities due to their excellent redox properties. The addition of lanthanum oxide can increase the content of adsorbed oxygen in the catalyst, further promoting the CO catalytic oxidation reaction. By preparing a copper-manganese-lanthanum composite oxide with stronger interactions, the CO oxidation activity can be further improved, the stability of the active component can be increased, the amount of active component can be reduced, the utilization rate of the metal active component can be increased, and the cost can be reduced. The successful application of this invention will not only completely solve the problem of high-value-added resource disposal of waste rare earth-based denitration catalysts, but also better address CO pollution as a CO oxidation catalyst, reduce the cost of CO oxidation catalysts, and simplify the catalyst processing technology, thereby bringing huge economic, environmental, and social benefits. Summary of the Invention

[0005] The present invention aims to provide a CO oxidation catalyst using spent rare earth-based denitrification catalysts as raw materials, thereby addressing the issue of resource recovery for discarded catalysts. Another object of the present invention is to address the current status and existing problems of existing CO oxidation catalysts by providing a method for preparing a CO oxidation catalyst that is simple, low-cost, and exhibits excellent activity.

[0006] The specific technical solutions of the present invention are:

[0007] A CO oxidation catalyst using waste rare earth-based denitration catalyst as raw material, wherein the catalyst carrier is prepared from waste rare earth-based denitration catalyst, diatomaceous earth and kaolin as raw materials, and copper manganese lanthanum composite oxide (CuMnLaO x ) is a catalytically active component;

[0008] The mass ratio of waste rare earth-based denitrification catalyst: diatomaceous earth: kaolin is 1: (0.1-2): (0.01-0.9); the molar ratio of Cu, Mn and La in the copper-manganese-lanthanum composite oxide is 1: (0.1-1): (0.1-1);

[0009] The mass ratio of carrier: catalytically active component is 1: (0.01-1).

[0010] In the technical solution of the present invention: the mass ratio of waste rare earth-based denitrification catalyst: diatomaceous earth: kaolin is 1: (0.6-1.2): (0.05-0.1); the molar ratio of Cu, Mn and La elements in the copper-manganese-lanthanum composite oxide is 1: (0.6-0.8): (0.1-0.2); the mass ratio of carrier: catalytically active component is 1: (0.05-0.2).

[0011] In the technical solution of the present invention: the waste rare earth-based denitrification catalyst is a used commercial cerium-based denitrification catalyst, in which: based on the carrier TiO2, the content of the active component CeO2 is 5%-10%, and the co-catalyst is WO3 with a content of 5%-10% and ZrO2 with a content of 1%-5%.

[0012] A method for preparing the above catalyst comprises the following steps:

[0013] (1) Preparation of carrier

[0014] The waste rare earth-based denitration catalyst, diatomaceous earth powder, kaolin powder and deionized water are mixed evenly, and stirred at 60-90°C for 1-2 hours to obtain a solid mixed liquid; the mixed liquid is filtered, dried and calcined to obtain a catalyst carrier;

[0015] (2) Preparation of active ingredient colloidal solution

[0016] Place copper salt, manganese salt, lanthanum salt, complexing agent and deionized water in the same container, and stir continuously at 60-90°C for 2-4 hours until the solution becomes clear and transparent, thereby obtaining a colloidal solution of the active component.

[0017] (3) Catalyst preparation

[0018] The catalyst carrier prepared in step (1) is immersed in the active component colloidal solution prepared in step (2) for 6 to 12 hours, and the impregnated catalyst carrier is taken out, dried, and calcined to obtain a CO oxidation catalyst.

[0019] In the above preparation method: the drying temperature in step (1) is 60-90° C., and the drying time is 6-12 hours; the calcination temperature is 350-550° C., and the calcination time is 2-4 hours.

[0020] In the above preparation method: the copper salt described in step (2) is copper nitrate or copper acetate, the manganese salt is manganese nitrate or manganese acetate, and the lanthanum salt is lanthanum nitrate; and the complexing agent is citric acid monohydrate or ethylenediaminetetraacetic acid.

[0021] In the above preparation method: the drying temperature in step (3) is 60-90° C., and the drying time is 6-12 hours; the calcination temperature is 350-550° C., and the calcination time is 2-4 hours.

[0022] Beneficial effects:

[0023] The catalyst of the present invention is suitable for CO purification and removal, and can achieve a 100% CO removal efficiency above 120°C. The main component of the waste rare earth-based denitrification catalyst is a titanium dioxide carrier with a large specific surface area and good stability. Its main active component is an environmentally friendly rare earth cerium-based composite oxide. Cerium dioxide (CeO2) has a unique fluorite structure and has high oxygen storage and release capacity and redox properties. The rich pore structure and large specific surface area of ​​diatomaceous earth can better disperse the active components. The addition of kaolin can make the catalyst better shaped and improve the mechanical strength of the catalyst. Copper oxide and manganese oxide have excellent catalytic oxidation of CO due to their excellent redox properties. The addition of lanthanum oxide can increase the content of adsorbed oxygen in the catalyst, further promoting the catalytic oxidation reaction of CO. By preparing a copper-manganese-lanthanum composite oxide with stronger interaction, the CO oxidation activity can be further improved, the stability of the active component can be improved, and the amount of the active component can be reduced, the utilization rate of the metal active component can be increased, and the cost can be reduced. Compared with existing CO oxidation catalysts, the catalyst of the present invention will not only completely solve the problem of high-value-added resource treatment of spent rare earth-based denitrification catalysts, but will also better solve CO pollution as a CO oxidation catalyst, reduce the cost of CO oxidation catalysts, and simplify the catalyst processing technology, thereby bringing huge economic, environmental and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a performance diagram of the CO conversion rate of the CO catalytic oxidation catalyst prepared in Examples 1-4. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the embodiments, but the protection scope of the present invention is not limited thereto.

[0026] The denitration performance of the catalyst of the present invention is evaluated as follows: the CO inlet concentration is 5000 ppm, the O2 content is 20%, N2 is used as the carrier gas, and the total gas flow rate is 1000 mL / min. The CO catalytic oxidation reaction is carried out in a fixed-bed reaction system. 3 mL of catalyst with a particle size of 40-60 mesh is measured and loaded into a quartz tube reactor with an inner diameter of 10 mm. The reaction space velocity (GHSV) is set to 20,000 h -1 The reaction temperature range was set to 80-240°C, and the flue gas analyzer was used to monitor the CO concentration changes before and after the reaction.

[0027] The waste rare earth-based denitration catalyst is a used commercial cerium-based denitration catalyst, wherein the active component is CeO2 (8%), the co-catalyst is WO3 (7%) and ZrO2 (3%), and the carrier is TiO2.

[0028] Example 1:

[0029] (1) Preparation of carrier

[0030] After the waste rare earth-based denitration catalyst, diatomaceous earth and kaolin are crushed and sieved, 10 g of waste rare earth-based denitration catalyst powder, 6 g of diatomaceous earth powder, 0.5 g of kaolin powder and 100 g of deionized water are weighed and placed in the same container according to the mass ratio of waste rare earth-based denitration catalyst: diatomaceous earth: kaolin of 1:0.6:0.05 and the mass ratio of waste rare earth-based denitration catalyst: deionized water of 1:10, and the mixture is stirred at 60°C for 1 hour to obtain a solid mixed liquid; the mixed liquid is filtered, dried at 60°C for 6 hours, and calcined at 350°C for 2 hours to obtain a catalyst carrier.

[0031] (2) Preparation of active ingredient colloidal solution

[0032] According to the molar ratio of Cu:Mn:La elements of 1:0.6:0.1 and the mass ratio of the total mass of metal salts / monohydrate citric acid of 1:0.8, 1.05g of copper nitrate, 0.60g of manganese nitrate, 0.18g of lanthanum nitrate, 1.46g of monohydrate citric acid and 50g of deionized water were weighed and placed in the same container. The mixture was stirred at 60°C for 2h until the solution became clear and transparent to obtain a colloidal solution of the active component.

[0033] (3) Catalyst preparation

[0034] The catalyst support prepared in step (1) was immersed in the colloidal solution of the active component prepared in step (2) for 6 hours at a mass ratio of support to catalytically active component of 1:0.05. The impregnated catalyst support was taken out and dried at 60°C for 6 hours and calcined at 350°C for 2 hours to prepare a CO oxidation catalyst.

[0035] (4) Catalyst performance evaluation see Figure 1 .

[0036] Example 2:

[0037] (1) Preparation of carrier

[0038] After the waste rare earth-based denitration catalyst, diatomaceous earth and kaolin are crushed and sieved, 10 g of waste rare earth-based denitration catalyst powder, 6 g of diatomaceous earth powder, 0.5 g of kaolin powder and 100 g of deionized water are weighed and placed in the same container according to the mass ratio of waste rare earth-based denitration catalyst: diatomaceous earth: kaolin of 1:0.6:0.05 and the mass ratio of waste rare earth-based denitration catalyst: deionized water of 1:10, and the mixture is stirred at 60°C for 1 hour to obtain a solid mixed liquid; the mixed liquid is filtered, dried at 60°C for 6 hours, and calcined at 350°C for 2 hours to obtain a catalyst carrier.

[0039] (2) Preparation of active ingredient colloidal solution

[0040] According to the molar ratio of Cu:Mn:La elements of 1:0.6:0.1 and the mass ratio of the total mass of the metal salt / ethylenediaminetetraacetic acid of 1:0.8, 1.12g of copper acetate, 0.58g of manganese acetate, 0.18g of lanthanum nitrate, 1.50g of ethylenediaminetetraacetic acid and 50g of deionized water were weighed and placed in the same container. The mixture was stirred at 60°C for 2h until the solution became clear and transparent to obtain a colloidal solution of the active component.

[0041] (3) Catalyst preparation

[0042] The catalyst support prepared in step (1) was immersed in the colloidal solution of the active component prepared in step (2) for 6 hours at a mass ratio of support to catalytically active component of 1:0.05. The impregnated catalyst support was taken out and dried at 60°C for 6 hours and calcined at 350°C for 2 hours to prepare a CO oxidation catalyst.

[0043] (4) Catalyst performance evaluation see Figure 1 .

[0044] Example 3:

[0045] (1) Preparation of carrier

[0046] After the waste rare earth-based denitration catalyst, diatomaceous earth and kaolin are crushed and sieved, 10 g of waste rare earth-based denitration catalyst powder, 12 g of diatomaceous earth powder, 1 g of kaolin powder and 100 g of deionized water are weighed and placed in the same container according to the mass ratio of waste rare earth-based denitration catalyst: diatomaceous earth: kaolin of 1:1.2:0.1 and the mass ratio of waste rare earth-based denitration catalyst: deionized water of 1:10, and the mixture is stirred at 60°C for 1 hour to obtain a solid mixed liquid; the mixed liquid is filtered, dried at 60°C for 2 hours, and calcined at 350°C for 2 hours to obtain a catalyst carrier.

[0047] (2) Preparation of active ingredient colloidal solution

[0048] According to the molar ratio of Cu:Mn:La elements of 1:0.8:0.2 and the mass ratio of the total mass of the metal salt / ethylenediaminetetraacetic acid of 1:1.2, 5.06g of copper acetate, 3.50g of manganese acetate, 1.65g of lanthanum nitrate, 12.25g of ethylenediaminetetraacetic acid and 50g of deionized water were weighed and placed in the same container. The mixture was stirred at 60°C for 2h until the solution became clear and transparent to obtain a colloidal solution of the active component.

[0049] (3) Catalyst preparation

[0050] The catalyst support prepared in step (1) was immersed in the colloidal solution of the active component prepared in step (2) for 6 hours according to the mass ratio of support to catalytically active component of 1:0.2. The impregnated catalyst support was taken out and dried at 60°C for 6 hours and calcined at 350°C for 2 hours to prepare a CO oxidation catalyst.

[0051] (4) Catalyst performance evaluation see Figure 1 .

[0052] Example 4:

[0053] (1) Preparation of carrier

[0054] After the waste rare earth-based denitration catalyst, diatomaceous earth and kaolin are crushed and sieved, 10 g of waste rare earth-based denitration catalyst powder, 12 g of diatomaceous earth powder, 1 g of kaolin powder and 100 g of deionized water are weighed and placed in the same container according to the mass ratio of waste rare earth-based denitration catalyst: diatomaceous earth: kaolin of 1:1.2:0.1 and the mass ratio of waste rare earth-based denitration catalyst: deionized water of 1:10, and the mixture is stirred at 90°C for 2 hours to obtain a solid mixed liquid; the mixed liquid is filtered, dried at 90°C for 12 hours, and calcined at 550°C for 4 hours to obtain a catalyst carrier.

[0055] (2) Preparation of active ingredient colloidal solution

[0056] According to the molar ratio of Cu:Mn:La elements of 1:0.8:0.2 and the mass ratio of the total mass of the metal salt / ethylenediaminetetraacetic acid of 1:1.2, 5.06g of copper acetate, 3.50g of manganese acetate, 1.65g of lanthanum nitrate, 12.25g of ethylenediaminetetraacetic acid and 50g of deionized water were weighed and placed in the same container. The mixture was stirred continuously at 90°C for 4h until the solution became clear and transparent to obtain a colloidal solution of the active component.

[0057] (3) Catalyst preparation

[0058] The catalyst support prepared in step (1) was immersed in the colloidal solution of the active component prepared in step (2) for 12 hours according to the mass ratio of support to catalytically active component of 1:0.2. The impregnated catalyst support was taken out and dried at 90°C for 12 hours and calcined at 550°C for 4 hours to prepare a CO oxidation catalyst.

[0059] (4) Catalyst performance evaluation see Figure 1 .

Claims

1. A CO oxidation catalyst using waste rare earth-based denitrification catalyst as raw material, characterized in that The catalyst is prepared from waste rare earth-based denitrification catalyst, diatomaceous earth and kaolin as raw materials to prepare the catalyst carrier, and copper manganese lanthanum composite oxide (CuMnLaO x ) is a catalytically active component; The mass ratio of waste rare earth-based denitrification catalyst: diatomaceous earth: kaolin is 1: (0.6~1.2): (0.05~0.1); the molar ratio of Cu, Mn and La elements in the copper-manganese-lanthanum composite oxide is 1: (0.6~0.8): (0.1~0.2); The mass ratio of carrier: catalytically active component is 1: (0.05~0.2); In the catalyst, based on the carrier TiO2, the content of the active component CeO2 is 5%-10%, and the co-catalyst is WO3 with a content of 5%-10% and ZrO2 with a content of 1%-5%.

2. A method for preparing the catalyst according to claim 1, characterized in that: The method comprises the following steps: (1) Preparation of carrier The waste rare earth-based denitration catalyst, diatomaceous earth powder, kaolin powder and deionized water are mixed evenly, and stirred at 60-90°C for 1-2 hours to obtain a solid mixed liquid; the mixed liquid is filtered, dried and calcined to obtain a catalyst carrier; (2) Preparation of active ingredient colloidal solution Place copper salt, manganese salt, lanthanum salt, complexing agent and deionized water in the same container and stir continuously at 60-90°C for 2-4 hours until the solution becomes clear and transparent to obtain a colloidal solution of the active ingredient; (3) Catalyst preparation The catalyst support prepared in step (1) is immersed in the active component colloidal solution prepared in step (2) for 6 to 12 hours, and the impregnated catalyst support is taken out, dried, and calcined to obtain a CO oxidation catalyst.

3. The method according to claim 2, wherein: The drying temperature in step (1) is 60-90° C., and the drying time is 6-12 hours; the calcination temperature is 350-550° C., and the calcination time is 2-4 hours.

4. The method according to claim 2, wherein: The copper salt in step (2) is copper nitrate or copper acetate, the manganese salt is manganese nitrate or manganese acetate, and the lanthanum salt is lanthanum nitrate; and the complexing agent is citric acid monohydrate or ethylenediaminetetraacetic acid.

5. The method according to claim 2, wherein: In step (3), the drying temperature is 60-90° C., and the drying time is 6-12 hours; the calcination temperature is 350-550° C., and the calcination time is 2-4 hours.

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