Multifunctional air purification material and preparation method thereof

Abstract

The invention belongs to the technical field of air purification, and particularly relates to a delta-MnO2 loaded modified carbon environment functional material and a preparation method thereof. According to the method, firstly, columnar activated carbon is modified through a ferric chloride solution, the surface structure and hydrophilicity of the columnar activated carbon are improved, surface active sites are increased, then the modified carbon is subjected to an in-situ reduction reaction in a potassium permanganate solution, and the nanoflower-shaped delta-MnO2 loaded modified carbon material is generated. The delta-MnO2 loaded modified carbon material prepared by the invention shows remarkable catalytic performance at room temperature on the basis of retaining the excellent adsorption performance of activated carbon, and formaldehyde is converted into harmless carbon dioxide and water. Compared with the traditional formaldehyde removal technology, the process is simple and convenient, a noble metal catalyst is not needed, and the production cost is reduced. Meanwhile, the material is stable and durable in catalytic performance, is less affected by environmental factors, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of air purification technology, specifically relating to a δ-MnO2 supported modified carbon composite material, its preparation method, and its application. Background Technology

[0002] Formaldehyde (HCHO) is a colorless gas with a strong, pungent odor. It primarily originates from indoor engineered wood products such as particleboard, medium-density fiberboard, and plywood, using adhesives primarily composed of urea-formaldehyde resin, which continues to release formaldehyde over time. Additionally, paints, varnishes, certain carpets, and some furniture and decorations may also release formaldehyde. Formaldehyde has been classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). Long-term exposure to high concentrations of formaldehyde can cause irritation to the eyes, nose, and throat, and may lead to chronic respiratory diseases.

[0003] To safeguard health, developing effective formaldehyde removal technologies is crucial. Common indoor air purification methods include biological purification, photocatalytic degradation, adsorption, and catalytic oxidation. Biological purification captures and transforms formaldehyde through plants or microorganisms, but its efficiency is greatly affected by the environment, resulting in limited removal effects. Photocatalytic degradation relies on photocatalysts and light, especially ultraviolet light, and its removal efficiency is low under poor light conditions. Adsorption is simple to operate, low in cost, and highly adaptable, but the adsorbent capacity is limited and requires regular replacement. Catalytic oxidation uses catalysts to oxidize formaldehyde into carbon dioxide and water, but effective catalysts at room temperature usually require precious metals, leading to high costs. In contrast, manganese dioxide (MnO2) exhibits excellent catalytic performance at room temperature and is relatively inexpensive, making it a promising formaldehyde removal technology. Manganese dioxide has various crystal forms (such as α-, β-, γ-, δ-, etc.), among which δ-MnO2, due to its unique structure and excellent catalytic performance, is an ideal choice for formaldehyde removal.

[0004] Carbon materials are excellent supported catalyst carriers; activated carbon and graphene, for example, have been widely used in the preparation of composite materials. Activated carbon, as a porous material widely used in industrial applications, possesses strong basic adsorption capacity, a large specific surface area, and thermal stability. Furthermore, the presence of its carbonized structure endows it with tunable electron transfer and charge storage characteristics. Its electronic structure can be further adjusted through modification with metallic substances, thereby improving its catalytic performance.

[0005] Currently synthesized formaldehyde removal materials can achieve formaldehyde removal to a certain extent, but their raw material composition and preparation process are quite complex. How to simplify the material preparation process, reduce costs, and achieve efficient and stable formaldehyde removal at room temperature is a pressing technical problem that needs to be solved. Summary of the Invention

[0006] The first technical problem solved by this invention is to provide an air purification material that removes formaldehyde at room temperature through adsorption and synergistic catalysis.

[0007] This invention relates to a modified carbon material loaded with δ-MnO2. This material is made by modifying columnar carbon with ferric chloride, retaining the high specific surface area advantage of columnar carbon while increasing oxygen-containing functional groups to enhance adsorption performance. Simultaneously, potassium permanganate is used as the manganese source to generate δ-MnO2 in situ on the carbon surface. This modified carbon material loaded with δ-MnO2 not only possesses high adsorption capacity but also exhibits strong catalytic oxidation ability at room temperature, capable of oxidizing formaldehyde into non-toxic carbon dioxide and water. Compared to single-component activated carbon and manganese dioxide, this invention offers better formaldehyde removal performance while reducing costs.

[0008] The second technical problem solved by this invention is to provide a method for preparing a structurally stable modified carbon material loaded with δ-MnO2 that can efficiently and rapidly remove formaldehyde at room temperature.

[0009] The preparation method of air purification material with modified carbon supported on δ-MnO2 includes the following specific steps:

[0010] a. Immerse the columnar charcoal in a ferric chloride solution. After immersion for a period of time, rinse thoroughly with deionized water until neutral, and dry at 50-100 ℃ to constant weight.

[0011] b. Add the ferric chloride-modified carbon prepared in step a and potassium permanganate to deionized water at a certain mass ratio. Stir at room temperature to generate δ-MnO2 in situ on the surface of the modified carbon.

[0012] c. After the reaction is complete, wash repeatedly with deionized water until neutral, and dry at 50~100 ℃ to obtain δ-MnO2 supported modified carbon.

[0013] In one embodiment, in step a, the columnar carbon is coal-based carbon; preferably, the columnar carbon is coal-based carbon with a diameter of 2 mm.

[0014] In one embodiment, in step a, the drying temperature is 50~100 ℃ and the drying time is 2~5 h; preferably, the drying temperature is 80 ℃ and the drying time is 3 h.

[0015] In one embodiment, in step a, the concentration of the ferric chloride solution is 0.1~1 mol / L; preferably, the concentration of the ferric chloride solution is 0.5 mol / L.

[0016] In one embodiment, in step b, the mass ratio of modified carbon to potassium permanganate is 5~20:1; preferably, the mass ratio of modified carbon to potassium permanganate is 10:1.

[0017] In one embodiment, in step c, the drying temperature is 50~100 ℃ and the drying time is 2~5 h; preferably, the drying temperature is 80 ℃ and the drying time is 3 h.

[0018] The third technical problem solved by this invention is to provide a structurally stable δ-MnO2-supported modified carbon that adsorbs and synergistically catalyzes the removal of formaldehyde at room temperature, and to apply it to the field of formaldehyde degradation and air purification.

[0019] The beneficial effects of this invention are:

[0020] 1. This invention utilizes an in-situ reduction method with potassium permanganate and modified carbon to achieve the loading of δ-MnO2 onto the surface of modified carbon without the addition of external reducing agents. Compared to traditional methods for preparing manganese dioxide, this invention eliminates the need for complex reducing agents (such as ethanol, hydrogen peroxide, etc.), simplifying the process, reducing the use of chemical reagents, and thus lowering environmental pollution and operational complexity.

[0021] 2. This invention significantly improves formaldehyde removal efficiency by loading δ-MnO2, leveraging its high specific surface area, good catalytic activity, and excellent structural stability. δ-MnO2, as a catalyst, exhibits excellent catalytic performance at room temperature and is not easily degraded, maintaining high activity over long-term use, thus providing a long-lasting and stable formaldehyde removal effect.

[0022] 3. The δ-MnO2 catalyst used in this invention does not rely on precious metal materials, and the cost of ferric chloride-modified carbon is lower than that of traditional catalyst supports. Through ferric chloride modification, the surface functionalization of the modified carbon is enhanced, effectively improving the loading and catalytic performance of manganese dioxide, ensuring low-cost and high-efficiency catalytic effects, making it particularly suitable for large-scale industrial applications. Attached Figure Description

[0023] Figure 1 The image shows the SEM image of the δ-MnO2-supported modified carbon obtained in Example 1.

[0024] Figure 2 The graph shows the formaldehyde removal efficiency obtained in Example 1.

[0025] Figure 3 The graph shows the formaldehyde removal efficiency obtained in Example 2.

[0026] Figure 4 The graph shows the formaldehyde removal efficiency obtained in Example 3. Detailed Implementation

[0027] This invention has undergone numerous experiments, and some of the experimental results are presented here for reference to further describe the invention in detail. The following is a detailed description in conjunction with specific embodiments.

[0028] Formaldehyde gas concentration test

[0029] Weigh 5 g of the prepared sample, place it in a petri dish, cover the petri dish with a petri dish cap, and then place it in a formaldehyde reactor with a reactor volume of 1 m³. 3 The chamber door was closed and the reaction chamber sealed. The formaldehyde evaporation device was placed inside the reaction chamber, and after complete evaporation and equilibrium was reached, the prepared sample was fully exposed to formaldehyde-containing air in the reactor. The formaldehyde gas concentration was determined using the phenol reagent spectrophotometric method, based on the People's Republic of China National Standard "Determination of Formaldehyde in Air of Public Places GB / T 18204.26-2000". For sample determination, 5 mL of phenol reagent absorption solution was measured in a colorimetric tube to absorb formaldehyde gas. After sampling, 0.4 mL of ferric ammonium sulfate solution was added, shaken well, and allowed to stand for 20 min. The absorbance of each solution was measured at 630 nm using a 1 cm cuvette on an ultraviolet spectrophotometer. Using the aqueous solution as a reference, the absorbance was converted to formaldehyde concentration using a standard curve.

[0030] Example 1

[0031] Synthesis process:

[0032] 10 g of columnar activated carbon was repeatedly washed with deionized water to remove surface ash and dried at 80 °C for 3 h. 10 g of activated carbon was then immersed in 50 mL of 0.5 mol / L FeCl3 solution for 2 h, followed by repeated washing with deionized water until neutral, and drying at 80 °C to obtain ferric chloride-modified carbon. The prepared ferric chloride-modified carbon and potassium permanganate were added to 500 mL of deionized water at a mass ratio of 5:1. The mixture was stirred at room temperature for 3 h, resulting in in-situ reduction of δ-MnO2 on the surface of the modified carbon. After the reaction, the carbon was repeatedly washed with deionized water until neutral and dried at 80 °C to obtain δ-MnO2-supported modified carbon (SEM image shown). Figure 1 As shown, ferric chloride-modified carbon surface is uniformly loaded with nano-flower-like δ-MnO2.

[0033] The above-mentioned δ-MnO2-supported modified carbon was used for the catalytic oxidation of formaldehyde, and the formaldehyde gas concentration was tested according to the formaldehyde gas concentration test method. The results are as follows: Figure 2 As shown, the δ-MnO2-supported modified carbon prepared in this embodiment was measured to have a 1.50 mg / m³ effect on the reactor after 20 h. 3 The formaldehyde removal rate reached 96%.

[0034] Example 2

[0035] Synthesis process:

[0036] 10 g of columnar activated carbon was repeatedly washed with deionized water to remove surface ash and dried at 80 ℃ for 3 h. Another 10 g of activated carbon was immersed in 50 mL of 0.5 mol / L FeCl3 solution for 2 h, then repeatedly washed with deionized water until neutral and dried at 80 ℃ to obtain ferric chloride-modified carbon. The prepared ferric chloride-modified carbon and potassium permanganate were added to 500 mL of deionized water at a mass ratio of 10:1. The mixture was stirred at room temperature for 3 h, resulting in in-situ reduction of δ-MnO2 on the surface of the modified carbon. After the reaction, the carbon was repeatedly washed with deionized water until neutral and dried at 80 ℃ to obtain δ-MnO2-supported modified carbon.

[0037] The above-mentioned δ-MnO2-supported modified carbon was used for the catalytic oxidation of formaldehyde, and the formaldehyde gas concentration was tested according to the formaldehyde gas concentration test method. The results are as follows: Figure 3 As shown, the δ-MnO2-supported modified carbon prepared in this embodiment was measured to have a 1.50 mg / m³ effect on the reactor after 20 h. 3 The formaldehyde removal rate reached 95.3%.

[0038] Example 3

[0039] Synthesis process:

[0040] 10 g of columnar activated carbon was repeatedly washed with deionized water to remove surface ash and dried at 80 ℃ for 3 h. Another 10 g of activated carbon was immersed in 50 mL of 0.5 mol / L FeCl3 solution for 2 h, then repeatedly washed with deionized water until neutral and dried at 80 ℃ to obtain ferric chloride-modified carbon. The prepared ferric chloride-modified carbon and potassium permanganate were added to 500 mL of deionized water at a mass ratio of 20:1. The mixture was stirred at room temperature for 3 h, resulting in in-situ reduction of δ-MnO2 on the surface of the modified carbon. After the reaction, the carbon was repeatedly washed with deionized water until neutral and dried at 80 ℃ to obtain δ-MnO2-supported modified carbon.

[0041] The above-mentioned δ-MnO2-supported modified carbon was used for the catalytic oxidation of formaldehyde, and the formaldehyde gas concentration was tested according to the formaldehyde gas concentration test method. The results are as follows: Figure 4 As shown, the δ-MnO2-supported modified carbon prepared in this embodiment was measured to have a 1.50 mg / m³ effect on the reactor after 20 h. 3 The formaldehyde removal rate reached 80.7%.

Claims

1. A method for preparing modified carbon supported on δ-MnO2 for formaldehyde removal, characterized in that, Modified carbon was obtained by impregnating columnar activated carbon with ferric chloride; at the same time, δ-MnO2 was generated in situ on the carbon surface by using potassium permanganate as a manganese source, thus obtaining modified carbon material loaded with δ-MnO2.

2. The method for preparing modified carbon supported on δ-MnO2 for formaldehyde removal according to claim 1, characterized in that, Includes the following steps: a. Immerse the columnar charcoal in a ferric chloride solution. After immersion for a period of time, rinse thoroughly with deionized water until neutral, and dry at 50-100 ℃ to constant weight. 3.b. The ferric chloride-modified carbon prepared in step a and potassium permanganate were added to deionized water at a certain mass ratio. The mixture was stirred at room temperature, resulting in in-situ reduction of δ-MnO2 on the surface of the modified carbon. 4.c. After the reaction is complete, wash repeatedly with deionized water until neutral, and dry at 50~100 ℃ to obtain δ-MnO2 supported modified carbon.

5. The method for preparing modified carbon supported on δ-MnO2 for formaldehyde removal according to claim 2, characterized in that, In step a, the columnar carbon is coal-based carbon.

6. The method for preparing modified carbon supported on δ-MnO2 for formaldehyde removal according to claim 2, characterized in that, In step a, the drying temperature is 50~100 ℃ and the drying time is 2~5 h.

7. The method for preparing modified carbon supported on δ-MnO2 for formaldehyde removal according to claim 2, characterized in that, In step a, the concentration of the ferric chloride solution is 0.1~1 mol / L.

8. The method for preparing modified carbon supported on δ-MnO2 for formaldehyde removal according to claim 2, characterized in that, In step b, the mass ratio of modified carbon to potassium permanganate is 5~20:

1.

9. A method for preparing modified carbon supported on δ-MnO2 for formaldehyde removal according to claim 2, characterized in that, In step c, the drying temperature is 50~100 ℃ and the drying time is 2~5 h.

10. A method for preparing formaldehyde-removing modified carbon supported on δ-MnO2 as described in claim 1, or an application of formaldehyde-removing modified carbon supported on δ-MnO2 prepared by any one of claims 2 to 7, characterized in that... It is used in the field of air purification to remove formaldehyde.

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