Fixing method and application of photocatalytic material

Abstract

The invention relates to the field of gas purification, and discloses a fixing method and application of a photocatalytic material, and the fixing method comprises the following steps: preparing a carrier, dispersing a powdery photocatalyst in an organic solvent, uniformly stirring to obtain a photocatalyst solution, spraying the photocatalyst solution on the carrier, and drying to obtain the photocatalytic material with purification capability. According to the invention, different amounts of photocatalysts are dispersed in the organic solvent, so that the carrier can realize the change of different loading capacities, the operation is simple, high temperature and high pressure are not needed, the fixation of the photocatalysts is stable and reliable, the prepared photocatalytic material has good degradation performance on ammonia gas, and the degradation rate on the ammonia gas within 24 hours can reach 92.5%.

Description

Technical Field

[0001] The present invention relates to the field of gas purification, and particularly to a method for fixing a photocatalytic material and its application. Background Art

[0002] In the photocatalytic reaction, under light irradiation, the photocatalytic material releases active free radicals with strong oxidizing properties, which degrade various large pollutant molecules into harmless small molecule pollutants. The whole reaction process is thorough and free of secondary pollution, and it is widely used in the removal of pollutants such as printing and dyeing wastewater, antibiotic wastewater, volatile organic compounds, and formaldehyde. However, currently, almost all photocatalytic materials are in powder form. Especially in waste gas treatment, the gas flow rate will carry away the powdered photocatalytic material, which is difficult to recover in practical applications, resulting in an increase in its use cost. As a result, almost all photocatalytic degradation of pollutants experiments are completed in the laboratory and it is difficult to play a role in practical applications. Summary of the Invention

[0003] The purpose of the present invention is to overcome the problem that the photocatalytic material is prone to loss in the prior art, and to provide a method for fixing a photocatalytic material and its application. This method is simple and easy to operate. At the same time, the loaded photocatalytic material is not easy to lose, which is beneficial to reducing its application cost.

[0004] To achieve the above purpose, the first aspect of the present invention provides a method for fixing a photocatalytic material, wherein the fixing method includes: Prepare a carrier; Disperse the powdered photocatalyst in an organic solvent and stir evenly to obtain a photocatalyst solution; Spray the photocatalyst solution on the carrier and dry it to obtain a photocatalytic material with purification ability.

[0005] By using the method of the present invention, only by dispersing different masses of photocatalyst in an organic solvent, the carrier can achieve different load changes. The operation is simple, without high temperature and high pressure, and the fixation of the photocatalyst is stable and reliable.

[0006] Preferably, the mass-volume ratio of the photocatalyst to the organic solvent is 2-10:100. The appropriate ratio of the photocatalyst to the organic solvent can not only make the fixation of the catalyst more stable, but also facilitate the subsequent drying step. The mass-volume ratio can be any value between any two numbers among 2:100, 2.5:100, 3:100, 5:100, 7:100, and 10:100.

[0007] There is no special requirement for the specific type of the photocatalyst. For example, it can be most photocatalysts such as g-C3N4, Cu2O, TiO2, MoO3, etc.

[0008] Preferably, the organic solvent is absolute ethanol. Using absolute ethanol as the solvent can effectively simplify the subsequent drying step. Air drying can be adopted, which is simple in operation and requires a short time.

[0009] Preferably, the step of preparing the carrier includes: cutting the carrier according to the required shape and size, and removing the surface impurities. The methods for removing surface impurities include cleaning, polishing (for carriers made of metal materials), etc., as long as the surface stains and oxides can be removed.

[0010] Preferably, the carrier is a filter screen. The material of the filter screen can be polyester fiber cotton or sponge. Such materials have a porous structure and a large specific surface area, which can provide rich attachment sites for the photocatalytic material, enabling the photocatalytic material to be evenly loaded on its surface and inside the pores. This not only increases the contact area between the photocatalytic material and the reactants but also increases the number of active sites for the photocatalytic reaction, thereby improving the efficiency of the photocatalytic reaction. In addition, polyester fiber cotton is soft in texture and has good flexibility, and can be processed into various shapes and sizes according to different application requirements, such as sheets, blocks, rolls, etc. This processability enables it to be conveniently applied to different types of photocatalytic reactors to meet diverse actual usage scenarios. Most importantly, the porous structures of polyester fiber cotton and sponge are conducive to the passage of polluted gases, enabling the polluted gases to fully contact the photocatalytic material and achieving efficient degradation.

[0011] The filter screen can be 100 - 300 mesh, which is selected according to needs. For example, if high requirements are placed on air resistance and pressure drop, a filter screen with a smaller mesh number can be selected.

[0012] The second aspect of the present invention provides an application of a photocatalytic material prepared by the fixing method according to the first aspect of the present invention in ammonia reduction.

[0013] In the present invention, by dispersing different amounts of photocatalyst in an organic solvent, different loadings of the carrier can be achieved. The operation is simple, without the need for high temperature and high pressure. The fixation of the photocatalyst is stable and reliable. The photocatalytic material thus prepared has good ammonia degradation performance, and the degradation rate of ammonia can reach up to 92.5% within 24 hours. Description of the Drawings

[0014] Figure 1 is the appearance of the cut filter screen prepared in Example 1; Figure 2 is the appearance of the filter screen after removing surface impurities prepared in Example 1; Figure 3 is the appearance of the photocatalytic material prepared in Example 1; Figure 4 is the appearance of the filter element prepared in Example 1; Figure 5SEM image of the filter element obtained in Example 1; Figure 6 SEM image of the filter element obtained in Example 3; Figure 7 SEM image of the filter element obtained in Comparative Example 1. Detailed Description of the Invention

[0015] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustration and explanation of the present invention, and are not intended to limit the present invention.

[0016] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0017] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0018] In addition, the term " / and" in the specification and claims is used to describe the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0019] In the following examples and comparative examples, unless otherwise specified, for reagents or instruments whose manufacturers are not indicated, they are all conventional products that can be obtained by commercial purchase. For those not indicating specific conditions in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. Example 1

[0020] Cut the filter mesh according to the size of the purification device. The material of the filter mesh is polyester fiber cotton. The size of the filter mesh is 20×20 cm, 200 meshes, and its appearance is as Figure 1As shown. The cut filter screen is washed and dried, and the obtained filter screen has an appearance as Figure 2 shown.

[0021] According to the mass-volume ratio of 5:200, 5 g of powdered photocatalyst is dispersed in anhydrous ethanol. The photocatalyst selected in this example is TiO2, and it is stirred evenly to obtain a photocatalyst solution.

[0022] The photocatalyst solution is filled into a spray bottle and evenly sprayed on the filter screen, and then air-dried to obtain a photocatalytic material, whose appearance is as Figure 3 shown.

[0023] The photocatalytic material prepared by the present invention is further made into a filter element of the required size, and its appearance is as Figure 4 shown. The result of its electron microscope scanning is as Figure 5 shown, and it can be seen that the photocatalyst is loaded on each wire of the filter screen. Example 2

[0024] The filter screen is cut according to the size of the purification device. The size of the filter screen is 20×20 cm and 200 meshes. The cut filter screen is washed and dried.

[0025] According to the mass-volume ratio of 10:200, 10 g of powdered photocatalyst is dispersed in anhydrous ethanol. The photocatalyst in this example is TiO2, and it is stirred evenly to obtain a photocatalyst solution.

[0026] The photocatalyst solution is filled into a spray bottle and evenly sprayed on the filter screen, and then air-dried to obtain a photocatalytic material. Example 3

[0027] The filter screen is cut according to the size of the purification device. The size of the filter screen is 20×20 cm and 200 meshes. The cut filter screen is washed and dried.

[0028] According to the mass-volume ratio of 20:200, 20 g of powdered photocatalyst is dispersed in anhydrous ethanol. The photocatalyst in this example is TiO2, and it is stirred evenly to obtain a photocatalyst solution.

[0029] The photocatalyst solution is filled into a spray bottle and evenly sprayed on the filter screen, and then air-dried to obtain a photocatalytic material. The result of its electron microscope scanning is as Figure 6 shown, and it can be seen that a large amount of photocatalyst is loaded on each wire of the filter screen.

[0030] Combined with Figure 5 and Figure 6, it can be seen that by adopting the method of the present invention and adjusting the mass-volume ratio of the photocatalyst and absolute ethanol, the amount of the photocatalyst loaded on the filter can be controlled. Compared with the traditional method where the fixed amount of the catalyst depends on the size of the reaction kettle, the method provided by the present invention is simple to operate and has strong controllability.

[0031] The filter element prepared in this example was placed in a photocatalytic reactor, and the ammonia degradation test was carried out according to the method of QB / T2761-2006. After 24 hours, the degradation rate of ammonia by the filter element prepared in the example of the present invention was measured to be as high as 92.5%.

[0032] Comparative Example 1 It was carried out in the same manner as in Example 1, with the only difference being that water was used instead of the photocatalyst (i.e., no photocatalyst was sprayed on the filter), and the obtained filter element was scanned by SEM. The results are as Figure 7 shown. It can be seen that compared with Example 1, each wire of the filter is very smooth, and there is obviously no photocatalyst loaded on it.

[0033] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any suitable combination of each specific technical feature. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. But these simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for fixing a photocatalytic material, characterized in that, The fixing method includes: Preparing a carrier; Dispersing the powdered photocatalyst in an organic solvent and stirring evenly to obtain a photocatalyst solution; Spraying the photocatalyst solution onto the carrier and drying to obtain a photocatalytic material with purification ability.

2. The fixing method according to claim 1, wherein The mass-volume ratio of the photocatalyst to the organic solvent is 2-10:

100.

3. The fixing method according to claim 1 or 2, wherein, The organic solvent is absolute ethanol.

4. The fixing method according to claim 3, wherein The step of preparing the carrier includes: cutting the carrier according to the required shape and size and removing the surface impurities.

5. The fixing method according to claim 4, wherein The carrier is a filter screen.

6. Application of a photocatalytic material prepared by the fixing method according to any one of claims 1-5 in ammonia reduction.

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