Method for preparing carbon monoxide normal-temperature oxidation catalyst based on electrolytic manganese residues and landfill leachate

Abstract

The invention discloses a method for preparing a carbon monoxide normal-temperature oxidation catalyst based on electrolytic manganese residues and landfill leachate. The method comprises the following steps: soaking and purifying the electrolytic manganese residues with deionized water to obtain preliminarily purified electrolytic manganese residues; mixing aryl alcohol dehydrogenase, the preliminarily purified electrolytic manganese residues and the landfill leachate, and standing to obtain enzymolysis electrolytic manganese residue slurry; mixing fly ash, red mud and the enzymolysis electrolytic manganese slag slurry, uniformly stirring, drying and grinding to obtain a multi-component composite raw material; placing the multi-component composite raw material in low-temperature plasma equipment for irradiation to obtain a plasma activated composite material; and carrying out hydrothermal reaction on the plasma activated composite material to obtain a hydrothermal structure composite material, dipping the hydrothermal structure composite material in a solution containing cerium nitrate, drying, and roasting to obtain the carbon monoxide normal-temperature oxidation catalyst. The carbon monoxide normal-temperature oxidation catalyst with high activity and high moisture resistance is prepared by utilizing industrial wastes and landfill leachate enzymolysis derivative liquid.

Description

Technical Field

[0001] This invention belongs to the field of industrial solid waste resource utilization, and in particular relates to a method for preparing a carbon monoxide oxidation catalyst at room temperature based on electrolytic manganese slag and landfill leachate. Background Technology

[0002] There is an urgent need for efficient CO oxidation catalysts in the fields of steel, coking, and confined spaces, which operate at room temperature (20-40℃) and high humidity (30%-90% relative humidity). However, existing precious metal catalysts are expensive and easily poisoned, non-precious metal catalysts require high temperature start-up and have poor humidity resistance, and carbon-based catalysts have insufficient activity at room temperature. Breakthroughs are urgently needed.

[0003] Electrolytic manganese slag contains high concentrations of manganese (8-15%), ammonia nitrogen, heavy metals, and acidic components, easily causing manganese pollution in groundwater. Landfill leachate contains high concentrations of organic matter (COD 5000-50000 mg / L), nitrogen and phosphorus, and recalcitrant pollutants, making the secondary treatment of its membrane treatment concentrate (accounting for 15-20% of the original water volume) a challenge. Currently, the main utilization methods for electrolytic manganese slag are to prepare it for the degradation of organic pollutants in water or to prepare it as a denitrification catalyst for flue gas. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides a method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate, thereby preparing a high-efficiency room-temperature carbon monoxide oxidation catalyst and achieving the reduction and harmless treatment of electrolytic manganese slag and landfill leachate.

[0005] The technical solution of this invention is as follows: A method for preparing a carbon monoxide oxidation catalyst at room temperature based on electrolytic manganese slag and landfill leachate, comprising the following steps:

[0006] The electrolytic manganese slag was soaked in deionized water to obtain preliminarily purified electrolytic manganese slag.

[0007] After mixing aryl alcohol dehydrogenase, pre-purifying electrolytic manganese slag and landfill leachate, and allowing them to stand, an enzymatically hydrolyzed electrolytic manganese slag slurry is obtained.

[0008] Mix fly ash, red mud, and enzymatically hydrolyzed manganese slag slurry, stir evenly, dry, and grind to obtain a multi-component composite raw material;

[0009] The multi-component composite material is irradiated in a low-temperature plasma device to obtain a plasma-activated composite material.

[0010] The plasma-activated composite material is subjected to a hydrothermal reaction to obtain a hydrothermal structural composite material, which is then impregnated in a solution containing cerium nitrate, and then dried and calcined to obtain a carbon monoxide room temperature oxidation catalyst.

[0011] Furthermore, the mass ratio of the mixed aryl alcohol dehydrogenase, the preliminarily purified electrolytic manganese slag, and the landfill leachate is 0.05–0.75:30–90:100.

[0012] Furthermore, the mass ratio of the mixed fly ash, red mud, and enzymatically hydrolyzed manganese slag slurry is 2.5–7.5:5–15:100.

[0013] Furthermore, when the immersion is in a solution containing cerium nitrate, the concentration of cerium nitrate in the solution is 0.15–0.9 mol / L, preferably 0.25–0.75 mol / L.

[0014] Furthermore, when the electrolytic manganese slag is soaked in deionized water, it is soaked for 4 to 24 hours at a solid-liquid ratio of 1:5 to 25 g / mL and then centrifuged.

[0015] Furthermore, the electrolytic manganese slag is soaked in deionized water, centrifuged, and then dried to constant weight at 50–150°C to obtain preliminarily purified electrolytic manganese slag.

[0016] Furthermore, when the multi-component composite material is irradiated in a low-temperature plasma device, the low-temperature plasma voltage is 5–75 kV and the low-temperature plasma treatment time is 10–30 minutes.

[0017] Furthermore, when the plasma-activated composite material undergoes a hydrothermal reaction, the plasma-activated composite material is mixed with water at a liquid-solid ratio of 1:5 to 25 g / mL, and reacted at 180 to 360°C for 4 to 16 hours.

[0018] Furthermore, when the hydrothermal structural composite material is impregnated in a solution containing cerium nitrate and then dried and calcined, the calcination temperature is 350–650℃ and the calcination time is 2–6 hours.

[0019] The reaction mechanism of this invention is as follows: Electrolytic manganese slag is soaked in deionized water to remove soluble impurities and some acid radicals from its surface. The electrolytic manganese slag is then mixed with aryl alcohol dehydrogenase and landfill leachate. The organic substrates in the leachate undergo oxidation under the catalysis of the aryl alcohol dehydrogenase. This not only decomposes the organic matter in the leachate, but the resulting enzymatic hydrolysis products combine with phosphorus and ammonium pollutants, causing chemical changes in the surface composition of the electrolytic manganese slag and promoting the redox reaction of surface functional groups, thereby forming catalytically active intermediate products. The mixture of fly ash, red mud, and enzymatically hydrolyzed electrolytic manganese slag slurry provides abundant silica-alumina and ferroalumina resources. The aluminosilicates in the fly ash react or interact with the electrolytic manganese slag and enzymatic hydrolysis products, while components such as iron oxide in the red mud further participate in the redox reaction. When multi-component composite raw materials are irradiated in a low-temperature plasma device, the low-temperature plasma contains a large number of high-energy particles that collide and interact with the surface of the raw materials. Electron impacts can excite atoms or molecules on the surface of the raw materials, putting them in a high-energy state and promoting the breaking of chemical bonds and the formation of new bonds. At the same time, active species such as free radicals can react with chemical groups on the surface of the raw materials, generating new active sites or changing the chemical composition and structure of the surface. Oxygen atoms on the surface of metal oxides are activated, forming active sites such as oxygen vacancies or peroxy groups, thereby improving the catalytic activity and chemical reactivity of the material. Under hydrothermal conditions, various components in the multi-component composite raw materials undergo complex chemical reactions and physicochemical changes in high-temperature and high-pressure water. Manganese oxides in electrolytic manganese slag, aluminosilicates in fly ash, titanium and iron oxides in red mud, and organic and inorganic components in enzymatic hydrolysis products interact under hydrothermal conditions, undergoing processes such as dissolution, reprecipitation, and crystallization. Manganese ions combine with silicate, aluminate, and other ions to form compounds such as silicates, aluminates, or manganese silicates with specific crystal structures. The hydrothermal composite material is immersed in a cerium nitrate solution. Through ion exchange and adsorption, cerium ions from the cerium nitrate are gradually loaded onto the surface and pores of the composite material. The drying process removes moisture, allowing cerium ions to form precursors on the composite surface and pre-react with manganese, titanium, iron, and various functional groups on the composite surface. During calcination, cerium nitrate decomposes into active cerium oxides at high temperatures, which then come into close contact with and react with the hydrothermal composite material to form a composite catalytic material.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention uses electrolytic manganese slag as the main raw material, providing manganese, iron, aluminum, silicon, and other metallic elements. Combined with enzymatic hydrolysis products from landfill leachate, it effectively utilizes the characteristics of industrial waste. The two work synergistically to form a self-catalytic system, while simultaneously introducing bioactive components to enhance catalytic performance. Organic matter in the leachate undergoes in-situ carbonization under manganese / iron catalysis, generating porous carbon with a high specific surface area. Simultaneously, manganese / iron is reduced to low-valence active centers. Humic acids and other macromolecules chelate with metal ions, and after low-temperature pyrolysis, can potentially form atomically dispersed sites such as Mn-OC and Fe-NC, which have the potential to significantly improve electron transfer efficiency. Furthermore, the alkaline components of the leachate neutralize the acidity of the electrolytic manganese slag, reducing the consumption of external alkali, while sulfates can induce the formation of acidic sites on the Mn-OS surface, inhibiting the competitive adsorption of water vapor at active sites, thereby enhancing catalytic performance under high humidity conditions.

[0022] This invention reduces the environmental impact by making rational use of industrial waste and enzymatic hydrolysis derivatives from landfill leachate, and produces a low-cost, highly active, and highly moisture-resistant room-temperature CO2 catalyst, which has significant environmental, economic, and social benefits. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of the method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. After reading this description, any modifications of this description in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0025] The process flow of the method for preparing carbon monoxide room temperature oxidation catalyst based on electrolytic manganese slag and landfill leachate in various embodiments of the present invention is as follows: Figure 1 As shown.

[0026] The raw materials involved in the various embodiments and comparative examples are described below:

[0027] Electrolytic manganese slag: The electrolytic manganese slag is sourced from Guizhou Energy and Minerals Manganese Industry Group Co., Ltd., and mainly includes 23.52% SO3, 13.17% SiO2, 15.21% CaO, 13.09% Fe2O3, 6.82% Al2O3, 10.21% MnO, 2.96% K2O, 1.55% MgO, 0.86% TiO2 and other components (unavoidable impurities and loss on ignition);

[0028] Red mud: provided by Shandong Zibo Zhengheng Aluminum Co., Ltd., the main tested components include: 38.52% Fe2O3, 27.83% Al2O3, 12.49% SiO2, 11.36% Na2O, 5.61% TiO2, 0.57% CaO, 0.34% SO3 and other components (unavoidable impurities and loss on ignition);

[0029] Fly ash: sourced from Huaneng International Power Development Corporation Taicang Power Plant, mainly comprising 43.21% SiO2, 27.08% Al2O3, 15.62% Fe2O3, 6.58% CaO, 3.42% TiO2, 1.43% SO3, 1.04% K2O, 0.63% Na2O and other components (unavoidable impurities and loss on ignition);

[0030] Landfill leachate: The landfill leachate used in the experiment was obtained from Zhuji Sanfeng Environmental Energy Co., Ltd. The COD concentration of this batch of landfill leachate was 4152 mg / L, the total phosphorus concentration was 305 mg / L, and the ammonia nitrogen concentration was 1075 mg / L.

[0031] Aryl alcohol dehydrogenase: Available online by Sigma-Aldrich, product number: A5228, specification: lyophilized powder.

[0032] Example 1: Effect of the mass ratio of aryl alcohol dehydrogenase, preliminarily purified electrolytic manganese slag, and landfill leachate on the performance of the prepared room temperature oxidation catalyst.

[0033] Electrolytic manganese slag was placed in deionized water and soaked for 24 hours at a solid-liquid ratio of 1:5 g / mL. After centrifugation, the slag was dried to constant weight at 50℃ to obtain preliminarily purified electrolytic manganese slag. The slag was then further purified by mass ratios of 0.025:30:100, 0.03:30:100, 0.04:30:100, 0.05:22.5:100, 0.05:25:100, 0.05:27.5:100, 0.05:30:100, 0.4:30:100, 0.75:30:100, 0.05:60:100, 0.4:60:100, and 0.75:60:100. A mixture of aryl alcohol dehydrogenase, preliminarily purified electrolytic manganese slag, and landfill leachate in ratios of 0.05:90:100, 0.4:90:100, 0.75:90:100, 0.75:35:100, 0.75:40:100, 0.75:45:100, 0.8:90:100, 0.85:90:100, and 0.9:90:100 was stirred evenly and allowed to stand for 0.5 days to obtain an enzymatically hydrolyzed electrolytic manganese slag slurry. Fly ash, red mud, and the enzymatically hydrolyzed electrolytic manganese slag slurry were then mixed in a mass ratio of 2.5:5:100, stirred evenly, dried, and ground to obtain a multi-component composite raw material. This multi-component composite raw material was then irradiated in a low-temperature plasma device to obtain a plasma-activated composite material. The low-temperature plasma voltage was 5 kV, and the irradiation time was 10 minutes. The plasma-activated composite material was mixed with water at a liquid-solid ratio of 1:5 g / mL and placed in a hydrothermal reactor. The temperature was set at 180℃ and the reaction time was 4 hours to obtain a hydrothermal structural composite material. The hydrothermal structural composite material was impregnated in a solution containing 0.25 mol / L cerium nitrate using an impregnation method, followed by drying and calcination to obtain a room-temperature oxidation catalyst. The calcination temperature was 350℃ and the calcination time was 2 hours.

[0034] Carbon monoxide oxidation experiment: Under ambient temperature (25 ± 1°C), CO was oxidized to CO2 by exciting the catalyst material with 185nm vacuum ultraviolet light (VUV). The vacuum UV lamp was a low-pressure mercury lamp (L-shaped quartz window, 185nm output ≥5mW·cm²). -2 (A 254 nm cutoff filter is optional); the photoreactor is a cylindrical high-purity quartz tube with an effective optical path length L = 10.0 cm, an inner diameter d = 2.0 cm, and a volume V = 31.4 mL; the vacuum system is a turbomolecular pump with a cold trap (ultimate vacuum < 1 × 10⁻⁶). -3 Pa); After the reactor is evacuated, press the set total pressure P. total =101kPa injection of mixed gas (CO:O2:N2=1:1:8 (volume ratio), initial CO concentration C) CO,0 (≈100 ppm), close the inlet and outlet valves, let stand for 5 minutes, and record the initial concentration C. CO,0 , Turn on the VUV lamp and start timing. Continuously record the concentrations of CO and CO2 at a sampling frequency of 1 Hz; the reaction time t = 0~30 min (preliminary experiments show that the reaction tends to reach equilibrium within 30 min). Keep the lamp power constant and measure the incident light intensity I0 using a UV radiometer (185 nm probe); record the temperature and pressure every 5 min, ensuring T = 25 ± 1°C and P change < 1%. Turn off the lamp and immediately extract the gas in the reactor to determine the final concentration C. CO,t , Potential water was captured using a cold trap, and the absence of other carbon-containing products was verified by gas chromatography-thermal conductivity detection (GC-TCD). The experiment was repeated three times, and the average value was taken. The ppm value (C) measured by the online analyzer was then used. CO,0 and C CO,t Convert y to mole fraction y CO,0 and y CO,t The number of moles of gas in the reactor is n = PV / (RT), where T = 298.15 K, and the carbon monoxide oxidation efficiency is η = (y CO,0 –y CO,t ) / y CO,0 ×100%.

[0035] The test results of this embodiment are shown in Table 1.

[0036] Table 1. Effects of the mass ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate on the performance of the prepared ambient temperature oxidation catalyst.

[0037]

[0038] As shown in Table 1, when the mass ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate is less than 0.05:30:100 (as shown in Table 1, when the mass ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate is 0.05:27.5:100, 0.05:25:100, 0.05:22.5:100, 0.04:30:100, 0.03:30:100, 0.025:30:100, and even lower ratios not listed in Table 1), the addition of aryl alcohol dehydrogenase and pre-purified electrolytic manganese slag is insufficient, resulting in incomplete reaction between the aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate. Consequently, the carbon monoxide oxidation efficiency decreases significantly as the mass ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate decreases. When the mass ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate is 0.05–0.75:30–90:100 (as shown in Table 1, the mass ratios of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate are 0.05:30:100, 0.4:30:100, 0.75:30:100, 0.05:60:100, 0.4:60:100, 0.75:60:100, 0.05:9...),... When the ratios are 0:100, 0.4:90:100, and 0.75:90:100, electrolytic manganese slag is mixed with aryl alcohol dehydrogenase and landfill leachate. The organic substrates in the leachate undergo oxidation under the catalysis of the aryl alcohol dehydrogenase. This not only decomposes the organic matter in the leachate, but the enzymatic hydrolysis products also combine with phosphorus and ammonium pollutants, causing chemical changes on the surface of the electrolytic manganese slag and promoting the redox reaction of surface functional groups, thus forming catalytically active intermediate products. Ultimately, the carbon monoxide oxidation efficiency is higher than 91% in all cases. When the mass ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate is greater than 0.75:90:100 (as shown in Table 1, the mass ratios of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate are 0.75:35:100, 0.75:40:100, 0.75:45:100, 0.8:90:100, 0.85:90:100, 0.9:90:100, and higher ratios not listed in Table 1), the mass ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate is too high. Excessive addition of aryl alcohol dehydrogenase and pre-purified electrolytic manganese slag leads to an imbalance in the reaction between aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate. This results in a significant decrease in carbon monoxide oxidation efficiency as the mass ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate further increases. Therefore, considering both benefits and costs, the optimal ratio of aryl alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate is 0.05–0.75:30–90:100 to maximize the CO oxidation performance of the prepared catalyst.

[0039] Example 2: Effect of the mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slurry on the performance of the prepared room temperature oxidation catalyst.

[0040] Electrolytic manganese slag was placed in deionized water and soaked for 14 hours at a solid-liquid ratio of 1:15 g / mL. After centrifugation, the slag was dried to constant weight at 100℃ to obtain pre-purified electrolytic manganese slag. Aromatic alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate were mixed in a mass ratio of 0.75:90:100, stirred thoroughly, and allowed to stand for 1.5 days to obtain an enzymatically hydrolyzed electrolytic manganese slag slurry. The slurry was then processed in mass ratios of 1:5:100, 1.5:5:100, 2:5:100, 2.5:2.5:100, 2.5:3:100, 2.5:4:100, 2.5:5:100, 5:5:100, 7.5:5:100, 2.5:10:100, 5:10:100, 7.5:10:100, 2.5:15: A mixture of fly ash, red mud, and enzymatically hydrolyzed electrolytic manganese slag slurry in ratios of 100, 5:15:100, 7.5:15:100, 7.5:17.5:100, 7.5:20:100, 7.5:22.5:100, 10:15:100, 12.5:15:100, and 15:15:100 was prepared, stirred evenly, dried, and ground to obtain a multi-component composite raw material. This multi-component composite raw material was then irradiated in a low-temperature plasma device to obtain a plasma-activated composite material. The low-temperature plasma voltage was 40 kV, and the irradiation time was 20 minutes. The plasma-activated composite material was then mixed with water at a liquid-to-solid ratio of 1:15 g / mL and placed in a hydrothermal reactor. The temperature was set at 270℃, and the reaction time was 10 hours to obtain a hydrothermal structural composite material. The hydrothermal structural composite material was impregnated in a solution containing 0.5 mol / L cerium nitrate using an impregnation method, followed by drying and calcination to obtain a room-temperature oxidation catalyst. The calcination temperature was 500℃ and the calcination time was 4 hours.

[0041] The carbon monoxide oxidation test was the same as in Example 1. The test results of this example are shown in Table 2.

[0042] Table 2. Effect of mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slag slurry on the performance of the prepared ambient temperature oxidation catalyst.

[0043]

[0044] As shown in Table 2, when the mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slag slurry is less than 2.5:5:100 (such as in Table 2, when the mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slag slurry is 2.5:4:100, 2.5:3:100, 2.5:2.5:100, 2:5:100, 1.5:5:100, 1:5:100, and even lower ratios not listed in Table 2), the addition of fly ash and red mud is insufficient, and the reaction of fly ash, red mud, and enzymatic electrolytic manganese slag slurry is incomplete. This leads to a significant decrease in carbon monoxide oxidation efficiency as the mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slag slurry decreases. When the mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slag slurry is 2.5~7.5:5~15:100 (as shown in Table 2, the mass ratios of fly ash, red mud, and enzymatic electrolytic manganese slag slurry are 2.5:5:100, 5:5:100, 7.5:5:100, 2.5:10:100, 5:10:100, 7.5:10:100, 2.5:15:100, 5:15:100, and 7.5:15:100), the fly ash, red mud, and enzymatic electrolytic manganese slag slurry are mixed. Fly ash and red mud provide abundant silica-alumina and ferroalumina resources. The aluminosilicates in fly ash react or interact with the electrolytic manganese slag and enzymatic products, while the iron oxide and other components in red mud further participate in the redox reaction. When multi-component composite materials are irradiated in a low-temperature plasma device, the plasma contains a large number of high-energy particles that collide and interact with the material surface. Electron impacts can excite atoms or molecules on the material surface, putting them in a high-energy state and promoting the breaking of chemical bonds and the formation of new bonds. Simultaneously, reactive species such as free radicals can react with chemical groups on the material surface, generating new active sites or altering the surface's chemical composition and structure. Oxygen atoms on the surface of metal oxides are activated, forming active sites such as oxygen vacancies or peroxy groups, thereby improving the material's catalytic activity and chemical reactivity. Ultimately, the carbon monoxide oxidation efficiency is higher than 94%. When the mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slurry is greater than 7.5:15:100 (as shown in Table 2, the mass ratios of fly ash, red mud, and enzymatic electrolytic manganese slurry are 7.5:17.5:100, 7.5:20:100, 7.5:22.5:100, 10:15:100, 12.5:15:100, 15:15:100, and higher ratios not listed in Table 2), the excessively high mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slurry leads to excessive addition of fly ash and red mud, resulting in an imbalance in the reaction of fly ash, red mud, and enzymatic electrolytic manganese slurry. Consequently, the carbon monoxide oxidation efficiency decreases significantly with further increases in the mass ratio of fly ash, red mud, and enzymatic electrolytic manganese slurry. Therefore, considering both benefits and costs, the optimal ratio of fly ash, red mud, and enzymatic electrolytic manganese slag slurry to 2.5-7.5:5-15:100 is most conducive to improving the oxidation performance of the prepared catalyst for CO.

[0045] Example 3: Effect of cerium nitrate concentration on the performance of the prepared room temperature oxidation catalyst.

[0046] Electrolytic manganese slag was soaked in deionized water at a solid-liquid ratio of 1:25 g / mL for 4 hours, centrifuged, and dried at 150℃ to constant weight to obtain pre-purified electrolytic manganese slag. Aromatic alcohol dehydrogenase, pre-purified electrolytic manganese slag, and landfill leachate were mixed at a mass ratio of 0.75:90:100, stirred evenly, and allowed to stand for 2.5 days to obtain an enzymatically hydrolyzed electrolytic manganese slag slurry. Fly ash, red mud, and the enzymatically hydrolyzed electrolytic manganese slag slurry were mixed at a mass ratio of 7.5:15:100, stirred evenly, dried, and ground to obtain a multi-component composite material. The multi-component composite material was irradiated in a low-temperature plasma device to obtain a plasma-activated composite material, wherein the low-temperature plasma voltage was 75 kV and the low-temperature plasma treatment time was 30 minutes. The plasma-activated composite material was mixed with water at a liquid-solid ratio of 1:25 g / mL, placed in a hydrothermal reactor, and the temperature was set at 360℃ for a reaction time of 16 hours to obtain a hydrothermal structural composite material. The hydrothermal structural composite material was impregnated in a solution containing 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.5 mol / L, 0.75 mol / L, 0.8 mol / L, 0.85 mol / L, and 0.9 mol / L cerium nitrate by impregnation method, followed by drying and calcination to obtain a room-temperature oxidation catalyst. The calcination temperature was 650℃ and the calcination time was 6 hours.

[0047] The carbon monoxide oxidation test was the same as in Example 1. The test results of this example are shown in Table 3.

[0048] Table 3 Effect of cerium nitrate concentration on the performance of the prepared room-temperature oxidation catalyst

[0049]

[0050] As shown in Table 3, when the cerium nitrate concentration is less than 0.25 mol / L (e.g., 0.2 mol / L, 0.15 mol / L, 0.1 mol / L in Table 3, and even lower values ​​not listed in Table 3), the addition of cerium nitrate is insufficient, resulting in inadequate reaction between cerium nitrate and the hydrothermal composite material. Consequently, the carbon monoxide oxidation efficiency decreases significantly with decreasing cerium nitrate concentration. When the cerium nitrate concentration is between 0.25 and 0.75 mol / L (e.g., 0.25 mol / L, 0.5 mol / L, and 0.75 mol / L in Table 3), under hydrothermal conditions, various components in the multi-component composite material undergo complex chemical reactions and physicochemical changes in high-temperature and high-pressure water. Manganese oxides in electrolytic manganese slag, aluminosilicates in fly ash, titanium and iron oxides in red mud, and organic and inorganic components in enzymatic hydrolysis products interact under hydrothermal conditions, undergoing processes such as dissolution, reprecipitation, and crystallization. Manganese ions combine with silicate, aluminate, and other ions to form compounds such as silicates, aluminates, or manganese silicates with specific crystal structures. The hydrothermal structural composite material is immersed in a cerium nitrate solution. Through ion exchange and adsorption, cerium ions from the cerium nitrate gradually load onto the surface and pores of the composite material. The drying process removes moisture, allowing cerium ions to form precursors on the composite surface and pre-react with manganese, titanium, iron, and various functional groups on the composite surface. During calcination, cerium nitrate decomposes into active cerium oxides at high temperatures, which come into close contact with and react with the hydrothermal structural composite material to form a composite catalytic material. Ultimately, the carbon monoxide oxidation efficiency is higher than 96%. When the cerium nitrate concentration is greater than 0.75 mol / L (as shown in Table 3, cerium nitrate concentrations = 0.8 mol / L, 0.85 mol / L, 0.9 mol / L, and higher values ​​not listed in Table 3), the excessively high concentration of cerium nitrate leads to an imbalance in the reaction between cerium nitrate and the hydrothermal structural composite material, resulting in a significant decrease in carbon monoxide oxidation efficiency with further increases in cerium nitrate concentration. Therefore, considering both benefits and costs, a cerium nitrate concentration of 0.25–0.75 mol / L is most favorable for improving the oxidation performance of the prepared catalyst for CO.

[0051] Comparative experiment: The effect of different preparation processes on the performance of the prepared room temperature oxidation catalyst.

[0052] Example 4 of this invention: Electrolytic manganese slag was placed in deionized water and soaked for 4 hours at a solid-liquid ratio of 1:25 g / mL. After centrifugation, the slag was dried to constant weight at 150°C to obtain preliminarily purified electrolytic manganese slag. Aromatic alcohol dehydrogenase, preliminarily purified electrolytic manganese slag, and landfill leachate were mixed at a mass ratio of 0.75:90:100, stirred evenly, and allowed to stand for 2.5 days to obtain an enzymatically hydrolyzed electrolytic manganese slag slurry. Fly ash, red mud, and the enzymatically hydrolyzed electrolytic manganese slag slurry were mixed at a mass ratio of 7.5:15:100, stirred evenly, dried, and ground to obtain a multi-component composite material. The multi-component composite material was irradiated in a low-temperature plasma device to obtain a plasma-activated composite material. The low-temperature plasma voltage was 40 kV, and the plasma treatment time was 30 minutes. The plasma-activated composite material was mixed with water at a liquid-solid ratio of 1:25 g / mL and placed in a hydrothermal reactor. The temperature was set at 360°C, and the reaction time was 16 hours to obtain a hydrothermal structural composite material. The hydrothermal structural composite material was impregnated in a solution containing 0.75 mol / L cerium nitrate using an impregnation method, followed by drying and calcination to obtain a room-temperature oxidation catalyst. The calcination temperature was 650℃ and the calcination time was 4 hours.

[0053] Comparative Example 1: Electrolytic manganese slag was placed in deionized water and soaked for 4 hours at a solid-liquid ratio of 1:25 g / mL. After centrifugation, it was dried to constant weight at 150℃ to obtain preliminarily purified electrolytic manganese slag. The preliminarily purified electrolytic manganese slag and landfill leachate were mixed at a mass ratio of 90:100, stirred evenly, and allowed to stand for 2.5 days to obtain electrolytic manganese slag slurry. Fly ash, red mud, and electrolytic manganese slag slurry were mixed at a mass ratio of 7.5:15:100, stirred evenly, dried, and ground to obtain a multi-component composite material. The multi-component composite material was irradiated in a low-temperature plasma device to obtain a plasma-activated composite material. The low-temperature plasma voltage was 40 kV, and the low-temperature plasma treatment time was 30 minutes. The plasma-activated composite material was mixed with water at a liquid-solid ratio of 1:25 g / mL and placed in a hydrothermal reactor. The temperature was set at 360℃, and the reaction time was 16 hours to obtain a hydrothermal structural composite material. The hydrothermal structural composite material was impregnated in a solution containing 0.75 mol / L cerium nitrate using an impregnation method, followed by drying and calcination to obtain a room-temperature oxidation catalyst. The calcination temperature was 650℃ and the calcination time was 4 hours.

[0054] Comparative Example 2: Electrolytic manganese slag was placed in deionized water and soaked for 4 hours at a solid-liquid ratio of 1:25 g / mL. After centrifugation, it was dried to constant weight at 150℃ to obtain preliminarily purified electrolytic manganese slag. Aryl alcohol dehydrogenase, preliminarily purified electrolytic manganese slag, and landfill leachate were mixed at a mass ratio of 0.75:90:100, stirred evenly, and allowed to stand for 2.5 days to obtain enzymatically hydrolyzed electrolytic manganese slag slurry. Fly ash, red mud, and enzymatically hydrolyzed electrolytic manganese slag slurry were mixed at a mass ratio of 7.5:15:100, stirred evenly, dried, and ground to obtain a multi-component composite material. The multi-component composite material was irradiated in a low-temperature plasma device to obtain a plasma-activated composite material, wherein the low-temperature plasma voltage was 40 kV and the low-temperature plasma treatment time was 30 minutes. The plasma-activated composite material was mixed with water at a liquid-solid ratio of 1:25 g / mL and placed in a hydrothermal reactor. The temperature was set at 360℃ and the reaction time was 16 hours to obtain a hydrothermal structural composite material. The hydrothermal structural composite material was calcined to obtain a room-temperature oxidation catalyst, wherein the calcination temperature was 650℃ and the calcination time was 4 hours.

[0055] The carbon monoxide oxidation test was the same as in Example 1. The results of this comparative test are shown in Table 4.

[0056] Table 4. Effects of different preparation processes on the performance of the prepared room-temperature oxidation catalysts.

[0057]

[0058] As shown in Table 4, the room temperature oxidation catalyst prepared in Example 4 of the present invention has significantly better oxidation catalyst performance than Comparative Example 1 and Comparative Example 2.

Claims

1. A method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate, characterized in that, Including the following steps: The electrolytic manganese slag was soaked in deionized water to obtain preliminarily purified electrolytic manganese slag. After mixing aryl alcohol dehydrogenase, pre-purifying electrolytic manganese slag and landfill leachate, and allowing them to stand, an enzymatically hydrolyzed electrolytic manganese slag slurry is obtained. Mix fly ash, red mud, and enzymatically hydrolyzed manganese slag slurry, stir evenly, dry, and grind to obtain a multi-component composite raw material; The multi-component composite material is irradiated in a low-temperature plasma device to obtain a plasma-activated composite material. The plasma-activated composite material is subjected to a hydrothermal reaction to obtain a hydrothermal structural composite material, which is then impregnated in a solution containing cerium nitrate, and then dried and calcined to obtain a carbon monoxide room temperature oxidation catalyst.

2. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, The mass ratio of the mixed aryl alcohol dehydrogenase, the preliminarily purified electrolytic manganese slag, and the landfill leachate is 0.05–0.75:30–90:

100.

3. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, The mass ratio of the mixed fly ash, red mud, and enzymatically hydrolyzed manganese slag slurry is 2.5–7.5:5–15:

100.

4. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, When the sample is immersed in a solution containing cerium nitrate, the concentration of cerium nitrate in the solution is 0.15–0.9 mol / L.

5. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, When the sample is immersed in a solution containing cerium nitrate, the concentration of cerium nitrate in the solution is 0.25–0.75 mol / L.

6. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, When the electrolytic manganese slag is soaked in deionized water, it is soaked for 4 to 24 hours at a solid-liquid ratio of 1:5 to 25 g / mL and then centrifuged.

7. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, The electrolytic manganese slag is soaked in deionized water, centrifuged, and then dried to constant weight at 50–150°C to obtain preliminarily purified electrolytic manganese slag.

8. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, When the multi-component composite material is irradiated in a low-temperature plasma device, the low-temperature plasma voltage is 5-75kV and the low-temperature plasma treatment time is 10-30 minutes.

9. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, When the plasma-activated composite material undergoes a hydrothermal reaction, the plasma-activated composite material is mixed with water at a liquid-solid ratio of 1:5 to 25 g / mL, and reacted at 180 to 360°C for 4 to 16 hours.

10. The method for preparing a room-temperature carbon monoxide oxidation catalyst based on electrolytic manganese slag and landfill leachate according to claim 1, characterized in that, When the hydrothermal structural composite material is impregnated in a solution containing cerium nitrate, and then dried and calcined, the calcination temperature is 350-650℃ and the calcination time is 2-6 hours.

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