CN105921145B - A kind of preparation method and application of purification air material - Google Patents

Abstract

The invention relates to a preparation method and application of an air-purifying material, which belongs to the preparation technology of metal composite functional materials. The method includes degreasing the aluminum or aluminum alloy substrate until the surface is completely moistened; dissolving permanganate in water, stirring to dissolve it fully, adding auxiliary agent ammonia or urea, and stirring until uniformly mixed; The processed aluminum base material is put into the mixed solution and then heated in a constant temperature water bath; finally, the aluminum base material is taken out, washed and dried. The preparation process of the present invention is simple and convenient, and the cost is low, and it is easy to realize large-scale production. Manganese oxide is firmly loaded on the surface of the aluminum base, which significantly improves the purification effect of formaldehyde in indoor air. And it can quickly degrade formaldehyde in indoor air at room temperature, and can further improve the performance of formaldehyde purification by heating the aluminum substrate to ensure the long-term use of the catalyst.

Description

Preparation method and application of a kind of air-purifying material

technical field

The invention relates to a method for growing manganese oxide in situ on the surface of an aluminum-based material, which belongs to the preparation technology of metal composite functional materials.

Background technique

The indoor environment is the main place where people live, work, study and socialize. Modern people spend at least 80% of their time indoors, and the quality of indoor air is closely related to our health. The composition of VOCs indoors is complex, and common ones include formaldehyde, benzene series, lower alcohols, ketones, etc., among which formaldehyde has a higher detection rate. In addition to the high detection rate, formaldehyde is the most harmful pollutant in indoor air. When formaldehyde reaches a certain concentration in the indoor environment, people will feel uncomfortable [Environ.Sci.Technol.2014,48,5816-5822]. A formaldehyde concentration greater than 0.08mg/ ^m3 may cause symptoms such as dermatitis, red eyes, itchy eyes, eye irritation, throat discomfort or pain, hoarseness, sneezing, chest tightness, and asthma. Long-term exposure to formaldehyde will have adverse effects on human health, and even lead to cancer. Therefore, in 2011, the National Toxicology Program of the United States listed formaldehyde as a known human carcinogen; and the International Organization for Research on Cancer identified formaldehyde as a human carcinogen in 2004.

Catalytic oxidation technology is considered to be a relatively effective and mature way to purify indoor formaldehyde. It is reported that noble metal catalysts can completely convert formaldehyde at room temperature [Angew.Chem.Int.Ed.2012,51,9628–9632], but its high cost limits its popularization and application. In addition to noble metal catalysts, currently commonly used metal oxidant catalysts are MnO ₂ , TiO ₂ , Fe ₂ O ₃ , CeO ₂ , Co ₃ O ₄ [ACS Catal.2015,5,2260-2269; Ind.Eng.Chem.Res. 2015, 54, 8900-8907; Environ.Sci.Technol.2011, 45, 3628-3634] and so on. Among them, manganese oxide has high activity for the removal of formaldehyde. For practical application, manganese oxide needs to be shaped or supported on some suitable carriers. At present, there are the following reports on the loading of manganese oxide. For example, researchers have loaded manganese oxide on alumina or activated carbon particles [Mater. type air purification equipment. Researchers at Stanford University loaded manganese oxides on porous textiles [Nano.Lett.2010,10,708-714]. The preparation process requires graphene to be coated on the surface of the textiles. The preparation process is complicated and the loading Manganese oxide is also not strong, and there is a phenomenon of slag falling. Therefore, it is necessary to develop a formaldehyde purification material with low wind resistance, simple preparation process, and low preparation cost.

As one of the lightest engineering structural materials, aluminum and aluminum alloys are favored due to their low density, high specific strength, good thermal and electrical conductivity, good wear resistance and corrosion resistance, beautiful color, good plasticity and easy pressure processing. Widely used in aerospace, automobiles, trains, electronics, home appliances, portable tools and other fields. Aluminum-based composite materials are composites that use aluminum or aluminum alloy as the matrix and other metals, non-metals, or their oxides to enhance the performance of the aluminum-based composite. This composite material maintains the characteristics of the aluminum matrix, while its performance is further improved. The performance of aluminum matrix composites mainly depends on the morphology, crystal form, size, performance and combination of the two phases of the composite phase. Therefore, developing the performance and application of aluminum matrix composites is an important research field of aluminum matrix composites. The problem to be solved in this application is how to firmly and easily load manganese oxide on the aluminum-based material. On the one hand, with the help of the wide application market of aluminum-based materials, the application of manganese oxide is popularized. After loading, the manganese oxide is easier to use, and at the same time It also expands the functions of aluminum-based materials and improves the added value of aluminum-based materials.

The usual practice of existing air conditioners with air purification function is to integrate the air purification device/module into the indoor air conditioner. When the gas passes through the air duct, most of the gas is not passed through due to the resistance of the purification device/module. Purification device/module is output, which also leads to low purification efficiency and poor purification effect of the air conditioner with air purification function in the prior art. Therefore, loading the catalyst on the radiator of the air conditioner can not only exert the air purification effect of the air purification device, but also make the air purification device/module have a low wind resistance value when only the air temperature adjustment function is turned on, so as not to affect the air conditioner air intake.

Contents of the invention

Aiming at the problems existing in the prior art, the invention proposes a preparation method and application of an air-purifying material. The invention solves the problem of how to firmly and easily load manganese oxide on aluminum and aluminum alloy materials. On the one hand, with the help of the wide application market of aluminum-based materials, the application of manganese oxides is promoted. After loading, manganese oxides are easier to use, and at the same time, the functions of aluminum-based materials are expanded to increase the added value of aluminum-based materials. The purpose of the present invention is to grow manganese oxide in situ on the surface of aluminum base, and provide a simple method for preparing formaldehyde purification material, so that the obtained manganese oxide can efficiently degrade formaldehyde in indoor air. The preparation method of the formaldehyde purification material is simple and low in cost. The manganese oxide supported by the in-situ oxidation method on the aluminum substrate in the present invention can degrade the formaldehyde in the indoor air at room temperature, taking advantage of the advantages of large surface area and easy preparation of the aluminum-based material, and at the same time, the aluminum-based material can be heated to further improve the indoor Purification efficiency of formaldehyde in air.

A kind of preparation method of air purification material of the present invention is characterized in that, this preparation method comprises the following steps:

(1) Degrease the aluminum or aluminum alloy substrate until the surface is completely moistened;

(2) Dissolve permanganate in water, stir to make it fully dissolved, add auxiliary agent ammonia or urea, stir until uniformly mixed;

(3) putting the aluminum base material processed in step (1) into the mixed solution of step (2) and then heating in a constant temperature water bath;

(4) taking out the aluminum-based material after step (3), washing and drying;

The concentration of permanganate in the mixed solution is 0.1-60g/L, and the concentration of ammonia water or urea is 1.0-40g/L.

The ratio of the surface area of the aluminum base to the concentration of permanganate is 0.2-28cm ² :0.1-60g/L.

The degreasing treatment in the step (1) uses a cleaning agent to clean the grease on the surface of the aluminum base, and then washes it with water; the cleaning agent is an acidic, alkaline or organic solvent degreasing agent.

The permanganate in the step (2) is a water-soluble permanganate, which is one of potassium permanganate, sodium permanganate, ammonium permanganate or any combination thereof.

The heating temperature of the constant temperature water bath in the step (3) is room temperature-95° C., and the time is 0.5-12 hours.

The drying temperature of the step (4) is room temperature-350°C.

The application of an air purifying material according to the present invention is characterized in that the purifying material can be applied to equipment and handicrafts that need to purify air.

The advantages of the present invention are mainly reflected in:

(1) The supported manganese oxide is synthesized in one step by the in-situ reduction method, the preparation process is simple, the cost is low, and it is easy to realize large-scale production.

(2) The manganese oxide is firmly loaded on the surface of the aluminum base, and the loading amount of the manganese oxide can be adjusted by adjusting the concentration of permanganate or the concentration of ammonia water/urea.

(3) The prepared manganese oxide utilizes the advantages of large surface area and easy preparation of aluminum-based materials, and significantly improves the purification efficiency of formaldehyde in indoor air.

(4) The invented purification material can rapidly degrade formaldehyde in indoor air at room temperature, and further improve the performance of formaldehyde purification by heating the aluminum substrate to ensure the long-term use of the catalyst.

Description of drawings

Figure 1 is the photos before and after the aluminum sheet is loaded with manganese oxide, Figure 1a is the aluminum sheet, and Figure 1b is the aluminum sheet after the manganese oxide is loaded.

Figure 2 is a schematic diagram of the electron microscope images before and after the aluminum sheet is loaded with manganese oxide, Figure 2a is the aluminum sheet, and Figure 2b is the manganese oxide/aluminum sheet.

Figure 3 is the photos before and after the surface of the heat exchanger of the air conditioner is loaded with manganese oxide, (a) is unloaded, and (b) is loaded.

Fig. 4 is the XPS spectrogram of the manganese oxide supported on the aluminum flake.

Figure 5 is a schematic diagram of the degradation effect of manganese oxide supported on aluminum flakes on formaldehyde at room temperature.

Detailed ways

The advantages of the present invention are further described below through specific examples, and the following descriptions do not limit the content of the present invention.

Example 1:

Weigh 6g of potassium permanganate, add it into 100mL of pure water, and sonicate until completely dissolved. Then add 4mL ammonia solution, stir and mix. Degrease and alkali wash the aluminum sheet with a mass of 20g to remove the grease and oxide layer on the surface, wash it with pure water until the surface is completely wet, and then put it into the above-mentioned potassium permanganate-ammonia water mixture. The solution was placed in a constant temperature water bath at 40°C for 5 h. Take out the aluminum sheet and dry it at 60°C to obtain the manganese oxide supported by the aluminum matrix.

Figure 1 is the before and after photos of manganese oxide supported on aluminum flakes. When the aluminum sheet is not loaded (Figure 1a), it shows a silver metal surface; after loading (Figure 1b), the color of the aluminum sheet is brown, indicating that a large amount of manganese oxide has been loaded on the surface of the aluminum sheet.

Figure 2 is a scanning electron microscope image of the aluminum sheet before and after loading manganese oxide. It can be seen from Figure 2a that before unloading, the surface of the aluminum sheet is relatively smooth; after loading (Figure 2b), the surface of the aluminum sheet is covered with a large number of manganese oxide nanoparticles.

Example 2:

Weigh 0.1g of potassium permanganate, add it into 100mL of pure water, and sonicate until completely dissolved. Then add 1 g of urea, stir and mix. A 0.7g aluminum sheet was degreased and washed with alkali to remove the grease and oxide layer on the surface, washed with pure water until the surface was completely wet, and then put into the above-mentioned potassium permanganate-urea mixture. The solution was placed in a constant temperature water bath at 95°C for 10 h. Take out the aluminum sheet and dry it at 105°C to obtain the aluminum-based supported manganese oxide.

Fig. 4 is an XPS diagram of Mn2p of manganese oxide supported on an aluminum base. It can be seen that there are two characteristic peaks at 653.4eV and 641.7eV respectively, and the energy interval of the two peaks is 11.7eV, which are consistent with Mn 2p _1/2 and Mn2p _3/2 in manganese dioxide respectively, thus It can be inferred that the manganese oxide supported on the aluminum-based material is mainly +4-valent manganese dioxide.

The removal effect of the manganese oxide-loaded aluminum-based material obtained in Example 2 on formaldehyde was measured at room temperature. The volume is 3.5L, the relative humidity is 30～60%, and the initial concentration is 300mg/m The aluminum-based material of the manganese oxide of 8g loading is placed in the measuring bottle to degrade the formaldehyde in the bottle. The formaldehyde concentration in the bottle was measured every hour, and the results are shown in Figure 5. After 5 hours, the formaldehyde in the bottle was basically degraded, indicating that the manganese oxide prepared by this method can be used as a formaldehyde purification material.

Example 3

On the fin of the metal heat exchanger of air conditioner, support the catalyst (as accompanying drawing 3) of degrading formaldehyde according to the method of the present invention. After the formaldehyde catalyst is loaded on the surface of the silver-white metal heat exchanger, the surface of the heat exchanger appears brown. The heat exchanger is fixed on the indoor unit of the air conditioner, and the air conditioner function and air purification function can be realized by controlling the remote control. When the air conditioner is running, start the air purification mode, and the indoor air enters the heat exchanger in the air conditioner shell through the air inlet. After heat exchange, the catalyst on the surface of the heat exchanger degrades the pollutants in the air, and then the clean air Flow out from the air outlet. To achieve air purification. Catalysts working in cooling mode or normal temperature mode can degrade indoor air pollutants; when the air conditioner is in heating mode, the heat emitted from the heat exchanger can quickly process the intermediate products accumulated on the surface of the catalyst, and significantly improve Purification of formaldehyde in indoor air.

The product directly made of the material of the present invention can also be used in a space that needs to purify the air, directly decompose formaldehyde and ozone in the air at room temperature, and then quickly regenerate the catalyst by heating.

Claims (6)

1. A preparation method of air-purifying material, characterized in that, the preparation method may further comprise the steps: (1) Degrease the aluminum or aluminum alloy substrate until the surface is completely moistened; (2) Dissolve permanganate in water, stir to make it fully dissolved, add auxiliary agent ammonia or urea, stir until uniformly mixed; (3) putting the aluminum base material processed in step (1) into the mixed solution of step (2) and then heating in a constant temperature water bath; (4) taking out the aluminum-based material after step (3), washing and drying; The concentration of permanganate in the mixed solution is 0.1-60g/L, and the concentration of ammonia or urea is 1.0-40g/L; The ratio of the surface area of the aluminum substrate to the concentration of permanganate is 0.2-28cm ² :0.1-60g/L. 2. The preparation method according to claim 1, characterized in that, the degreasing treatment in the step (1) uses a cleaning agent to clean the grease on the surface of the aluminum or aluminum alloy substrate, and then washes it with clear water; The above-mentioned cleaning agent is a degreasing agent for acidic, alkaline or organic solvents. 3. preparation method according to claim 1, is characterized in that, the permanganate in described step (2) is water-soluble permanganate, is the one in potassium permanganate, sodium permanganate or any combination of them. 4. The preparation method according to claim 1, characterized in that, the heating temperature of the constant temperature water bath in the step (3) is room temperature-95°C, and the time is 0.5-12 hours. 5. The preparation method according to claim 1, characterized in that, the drying temperature of the step (4) is room temperature-350°C. 6. According to the application of the air-purifying material obtained by the preparation method of the air-purifying material described in any one of claims 1-5, it is characterized in that, the air-purifying material is applied to an air purifying device with a heating function equipment.