CN116920830B - Ozonolysis photocatalyst coating and preparation method and application thereof - Google Patents

Abstract

The invention relates to the field of ozone decomposition control and the field of catalytic chemistry, specifically to an ozone decomposition photocatalyst coating, a load material, an adhesive layer and a photocatalyst; the surface of the load material is wrapped with an adhesive layer; the photocatalyst is attached to the load material through the adhesive layer surface; the adhesive layer includes one of a mixture of silica sol and polysaccharide, dopamine hydrochloride or tannic acid; the photocatalyst is nanosilver; the invention also provides a preparation method of an ozone decomposition photocatalyst coating and an ozone decomposition photocatalyst coating. The application of the layer in ozone treatment; the present invention can increase the ozone degradation rate, has a simple preparation process and no pollutants are generated during the preparation process, forms a stable superhydrophobic surface, has high impact resistance and does not affect the catalytic activity, and has good Stable performance.

Description

An ozone decomposition photocatalyst coating and its preparation method and application

Technical field

The invention relates to the field of ozone decomposition control and catalytic chemistry, and specifically to an ozone decomposition photocatalyst coating and its preparation method and application.

Background technique

Ozone, as a product of photochemical reactions, is one of the common indoor air pollutants. It has strong oxidizing properties. High concentrations of ozone can strongly stimulate the body's mucosal tissues, cause cardiovascular and respiratory diseases, and pose a huge threat to human health. Ozone has strong damage to the ecosystem. It will not only weaken the photosynthesis efficiency of plants, but even kill cells, causing plant leaves to become necrotic and fall off prematurely, causing crop yield reduction and potential food supply problems. Therefore, studying the elimination of ozone is of great significance for protecting human health and maintaining the ecological environment.

At present, ozone removal technologies at home and abroad mainly include thermal decomposition, activated carbon adsorption, solvent absorption, radiation decomposition and catalytic decomposition. Photocatalytic ozone decomposition technology accelerates the decomposition of ozone into oxygen through active sites on the photocatalyst. It has the advantages of high decomposition efficiency and eco-friendliness, making it a promising method. Among them, the supported photocatalyst can support the photocatalyst on the carrier to increase the stability and activity of the photocatalyst, thereby improving the efficiency of the ozone oxidation reaction. The reaction rate of ozone-resistant pollutants limits ozonation, and photocatalytic ozonation can well overcome these shortcomings.

The development of efficient photocatalysts is of great significance for the photocatalytic ozonation treatment of organic wastewater. Yang et al. synthesized ZnO nanocomposites with different preferentially exposed crystal faces (ZnO-rods and ZnO-disks). The exposed {0001} faces and oxygen vacancies promoted the separation and transfer of photogenerated charges and improved the performance of ozone molecules in light. Adsorption and activation of catalyst surfaces. Gmurek et al. enhanced the photocatalysis-based process by monometallic and bimetallic (Cu/Pd)-loaded TiO2 nanoparticles, and could obtain excellent photocatalytic ozonation efficiency under visible light for the removal of antibiotic resistance genes and facultative pathogens. Wang et al. used a one-step redox method to grow NiFeOOH nanosheets in situ on the surface of nickel foam, and efficiently converted ozone into hydroxyl radicals under the excitation of a UV LED lamp with a wavelength of 365 nm, showing significant light emission in an ultra-short retention time. Catalytic inactivation efficiency.

However, the impact of the exposed surface and surface defects of the photocatalyst on the photocatalytic ozonation performance has rarely been mentioned. In particular, the photocatalyst is particularly sensitive to high-humidity environments. In high-humidity environments, the competitive adsorption of water molecules and ozone will block the photocatalyst. The surface catalytically oxidizes the active sites of ozone, resulting in a reduction in ozone degradation efficiency, and water vapor erosion causes the photocatalyst to be unstable and easily deactivated, and the coating is easy to fall off, seriously affecting the service life of the photocatalyst.

In the prior art, there are methods to select solutions of different proportions of manganese sulfate, ferric nitrate, copper nitrate and silver nitrate and mix them with molecular sieve powder to obtain loaded molecular sieve powder. By combining the loaded molecular sieve powder and using trimethyl chloride on the surface of the gel, Silane treatment further improves the hydrophobicity of the aerogel. There is another method for preparing a hydrophobic room-temperature ozone decomposition photocatalyst. This method mixes the high-temperature activated ozone decomposition photocatalyst with the silane coupling agent hydrolysis solution, so that the silane oxygen group on the silane coupling agent is grafted to the photocatalyst. The surface is treated at high temperature to obtain a hydrophobic photocatalyst for decomposing ozone at room temperature. There is also a method for preparing a nano-alumina hybrid modified styrene-divinylbenzene copolymer hydrophobic photocatalyst carrier. In this preparation method, nano-alumina modified by heptadecafluorodecyltrimethoxysilane is introduced. Aluminum oxide, through the excellent mechanical properties of inorganic nanoparticles, greatly improves the compressive strength and hydrophobicity of SDB hydrophobic photocatalyst carrier.

Modifying a superhydrophobic coating on the surface of a photocatalyst or carrier can effectively improve stability problems and prevent the coating from absorbing water and falling off. However, the operation process is complicated, the cost increases, and the active sites are easily blocked, resulting in lower degradation efficiency. Even some fluorine-containing hydrophobic modifications Agents can cause secondary pollution. Due to the low light penetration of the deep pores of the carrier, the photocatalyst coated on the porous substrate cannot generate enough ROS to catalyze ozone decomposition. In this case, not only will the photocatalyst be wasted, but bacteria will also invade deep pores to survive and reproduce under suitable culture conditions, causing secondary pollution.

Contents of the invention

In view of the shortcomings of the existing technology, one of the purposes of the present invention is to provide a hydrophobic ozone decomposition photocatalyst coating suitable for high humidity environments. The synthesized catalytic material can achieve efficient decomposition of ozone in a short time, and has a simple preparation method, good stability and long service life.

The second object of the present invention is to provide a preparation method for an ozone decomposition photocatalyst coating. The preparation method of the coating can form hydrophobicity in situ on the surface of the nanosilver photocatalyst without the need for additional hydrophobic modifiers, and is environmentally friendly. , which solves the problems of existing supported ozone decomposition photocatalysts, such as the catalytic activity of the photocatalyst being greatly reduced in a high-humidity environment, the additional hydrophobic modification process being complicated, causing environmental pollution, and the active sites being easily blocked, resulting in low ozone degradation efficiency. .

The third object of the present invention is to provide the application of ozone decomposition photocatalyst coating in ozone treatment.

One of the purposes of the present invention is achieved by adopting the following solutions:

An ozone decomposition photocatalyst coating, including: a load material, an adhesive layer and a photocatalyst;

The surface of the load material is wrapped with an adhesive layer; the photocatalyst is attached to the surface of the load material through the adhesive layer;

The adhesive layer includes one of a mixture of silica sol and polysaccharide, dopamine hydrochloride or tannic acid;

The photocatalyst is nanosilver.

Optionally, the load material is one of foam metal mesh, cotton fabric, honeycomb activated carbon or sponge, which has the advantage of high specific surface area.

Optional, the pore size of the foam metal mesh is ≤400μm. The pore size of the foam metal mesh is ≤400 μm, which can increase the loading capacity of nanosilver on the foam metal mesh, thereby improving the photocatalytic performance of ozone. At the same time, it is avoided that the surface roughness is reduced due to excessive pore diameter and affects the superhydrophobic effect of the coating.

Optionally, the molar ratio of silica sol to polysaccharide in the mixture of silica sol and polysaccharide is 1:7-9. The molar ratio of silica sol to polysaccharide is selected to be 1:7-9 to form a blended solution with optimal stability and adhesion. If the ratio is too low, the solution will have poor adhesion, and if the ratio is too high, the solution will harden and affect its use.

The second object of the present invention is achieved by adopting the following solutions:

A preparation method for an ozone decomposition photocatalyst coating, including the following steps:

(1) Soak the load material in the adhesive and adjust the pH of the adhesive, then take out the load material and irradiate it with ultraviolet light to coat the surface of the load material with an adhesive layer; the adhesive is a mixture of silica sol and polysaccharide One of liquid, dopamine hydrochloride or tannic acid;

(2) Add AgNO ₃ to the ethanol aqueous solution and mix well to obtain mixed solution A;

(3) Add ammonia solution dropwise to mixed solution A in step (2) until the precipitate at the bottom of mixed solution A completely disappears to obtain mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C; immerse the load material treated in step (1) into mixed solution C, perform ultrasonic treatment, then take out the load material, rinse; repeat immersion, Ultrasonic treatment, removal of the load material, rinsing operations, and finally drying of the load material;

(5) The loaded material dried in step (4) is irradiated with ultraviolet light to obtain.

Glucose is used as a reagent. In this technology, glucose has dual-functional properties. It can not only be used as a reducing agent for nano-silver, reducing silver ions to nano-silver; at the same time, glucose adsorbed on the surface of the coating can be used as a superhydrophobic precursor, which can be used during UV irradiation. Chemical deoxidation and cross-linking occur, resulting in a superhydrophobic surface on the coating surface. It avoids the shortcomings of the prior art that the super-hydrophobic coating surface requires additional hydrophobic modifiers, complicated operations, and uneven coating.

Further, the concentration of the adhesive in step (1) is 2-5 mg/mL. The concentration of the adhesive solution selected is 2-5 mg/mL, which can form a thick enough adhesive film on the surface of the load material and improve the stability of the nano-silver loading on the load material. If the concentration is too high, the adhesive film layer will be too thick. Wrapping nano-silver affects the ozone degradation effect; the concentration is too low, the adhesive film layer is too thin and easy to fall off, and the material stability is poor.

Further, the pH of the adhesive in step (1) is 7.5-10.0. The pH range of 7.5-10.0 was chosen because the prepared adhesive film has the best adhesion performance and stability.

Further, in step (1), the ultraviolet light irradiation intensity is 500-1000W, and the irradiation time is 15-35 minutes. The ultraviolet light irradiation intensity range is selected to be 500-1000W, which can accelerate the polymerization of the adhesive on the surface of the load material, form a stable adhesive film layer, and shorten the polymerization time. If the irradiation intensity is too low, it will affect the polymerization effect of the adhesive, and the adhesive film layer will be too thin and have poor stability. Excessive irradiation intensity will destroy the internal molecular structure and prevent the formation of an adhesive film.

Further, the thickness of the adhesive layer in step (1) is 5-60 nm. The thickness of the adhesive layer is 5-60nm because the adhesive film with a thickness in this range can not only adhere to a sufficient amount of nanosilver, but can also be stably fixed on the load material to prevent it from falling off. If the adhesive film layer is too thick, it will wrap the nano-silver, which will affect the ozone degradation effect; if the concentration is too low, the adhesive film layer will fall off if it is too thin, and the material stability will be poor.

Further, the volume concentration percentage of ethanol in the ethanol aqueous solution in step (2) is 9-13%. The volume concentration percentage of ethanol in the ethanol aqueous solution is selected to be 9-13%, which can control the slightly alkaline pH value, optimize the reduction effect of nanosilver, and shorten the reaction time. If the ethanol volume concentration is too low, the reaction time will be too long and the amount of nanosilver reduced will be small. The ethanol volume concentration is too high, the pH is too high, the reaction is too fast, and a large amount of black silver particles are precipitated, making it difficult to obtain high-quality nanosilver.

Further, the mass concentration percentage of AgNO ₃ in the aqueous ethanol solution in step (2) is 2-3.5%. After a certain amount of AgNO ₃ is added to the ethanol aqueous solution with the above volume concentration, a mixed solution is formed. The mass concentration of AgNO ₃ is too high, resulting in residual waste, and the concentration is too low, resulting in a reduction in the concentration of nanosilver, resulting in a large loading of nanosilver on the load material. Less, affecting the ozone degradation effect.

Further, the molar ratio of silver ions to glucose in the mixed solution C of step (4) is 0.15-0.25:1. Mix silver ions and glucose at a molar ratio of 0.15-0.25:1. Glucose can fully reduce silver ions into nanosilver, while reducing the remaining glucose to avoid waste. Too high a ratio will lead to incomplete reduction of silver ions.

Further, in step (4), ultrasonic treatment is performed at 75-90°C for 6-12 min/time. Within the above temperature range, the morphology and size of nanosilver particles are uniform, which can improve the stability and loading speed of nanosilver loading on the load material, thereby improving the ozone degradation performance of the material.

Further, in step (5), the wavelength of ultraviolet light is 365nm, the irradiation intensity is 500-1500W, and the irradiation time is 10-30 minutes. The wavelength of ultraviolet light is selected as 365nm because the ultraviolet light in this band can most efficiently stimulate the LSPR effect of nanosilver. The irradiation intensity is selected as 500-1000W because it can make the hydrophilic adsorbent glucose on the surface of the coating be absorbed by the LSPR of nanosilver. Fully deoxidized and cross-linked to transform the coating from super hydrophilic to super hydrophobic. If the irradiation intensity is too low and the glucose reaction is incomplete, the superhydrophobicity of the coating surface will decrease. Excessive irradiation intensity will cause the deformation of silver nanoparticles and affect the ozone degradation effect.

The third object of the present invention is achieved by adopting the following solutions:

Application of ozone decomposition photocatalyst coating in ozone treatment. Photocatalyst combined with ultraviolet light is used for synergistic catalytic decomposition of ozone in the air under normal temperature and high humidity environment. Specifically, photocatalyst coating is used for ozone decomposition under high humidity environment. During the reaction process, the reaction temperature is 25°C, the relative humidity is not less than 80%, and the ozone concentration is not less than 40ppm.

The beneficial effects of the present invention are:

1. The ozone decomposition photocatalyst coating of the present invention forms a hydrophobic layer on the surface, and the water-based solution is prepared, which is green and environmentally friendly, and does not require the use of toxic hydrophobic modifiers;

2. The nano-silver particles with specific wavelength response in the ozone decomposition photocatalyst coating of the present invention produce a strong plasmon effect, which can reduce ozone and achieve rapid decomposition. At the same time, its intrinsic hydrophobicity makes it adaptable to high humidity environments and maintain Ozonolysis activity;

3. The ozone decomposition photocatalyst coating of the present invention binds the load material and the nano-silver photocatalyst with an environmentally friendly adhesive, which improves the high impact resistance of the material without affecting the catalytic activity, and can successfully overcome the easy falling off of the hydrophobic coating. problem, thereby extending the service life of the photocatalyst. Both the loading material and nanosilver have high specific surface areas, which provide more active sites for ozone decomposition and improve the decomposition efficiency.

Description of drawings

Figures 1-2 are respectively SEM images of the photocatalyst coating before and after ultraviolet irradiation in Example 1.

Figures 3-4 are respectively the static contact angle detection results of the photocatalyst coating before and after ultraviolet irradiation in Example 1.

Figure 5 is the XRD spectrum of the photocatalyst coating in Example 1;

Figure 6 is a diffuse reflection ultraviolet-visible light absorption spectrum chart of the photocatalyst coating in Example 1.

Figures 7-8 are respectively XPS peak diagrams before and after ultraviolet irradiation of the photocatalyst coating in Example 1.

Figure 9 is a diagram showing the ozone removal effect of the photocatalyst with different regeneration times in Example 1.

Detailed ways

The present invention will be described in further detail below in conjunction with specific embodiments. However, this should not be understood to mean that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. All technologies implemented based on the contents of the present invention belong to the scope of the present invention.

Example 1

An ozone decomposition photocatalyst coating, its preparation method includes the following steps:

(1) Soak the clean metal foam mesh in a mixed solution of 4 mg/mL silica sol and polysaccharide with pH = 8.5. The molar ratio of silica sol to polysaccharide is 1:8; then take out the metal foam mesh and irradiate it with UV light for 30 minutes. The irradiation intensity is 990W, so that the surface of the foam metal mesh is wrapped with an adhesive layer with a thickness of 50 nm; the pore size of the foam metal mesh is 300 μm;

(2) Add AgNO ₃ to an ethanol aqueous solution with a volume concentration of 12%. The mass concentration of AgNO ₃ in the ethanol aqueous solution is 3%. Mix well to obtain mixed solution A;

(3) Add an ammonia solution with a mass concentration of 2% to the mixed solution A in step (2) dropwise until the precipitate at the bottom of the mixed solution A completely disappears to obtain the mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C. The molar ratio of silver ions to glucose in mixed solution C is 0.22:1; immerse the foam treated in step (1) into mixed solution C. metal mesh, and perform ultrasonic treatment at 80°C for 7 minutes, ultrasonic power 100W, frequency 45kHz, then take out the foam metal mesh and rinse with water; repeat the immersion, ultrasonic treatment, take out the foam metal mesh, rinse with water 4 times, and finally remove the foam The metal mesh is vacuum dried at room temperature;

(5) Use a 365nm UV LED lamp to irradiate the dry foam metal mesh in step (4) for 20 minutes with an irradiation intensity of 1000W to prepare it.

The comparison of scanning electron microscopy before and after UV irradiation of the photocatalyst coating in Example 1 is shown in Figure 1-2. The static contact angle detection results of the photocatalyst coating in Example 1 before and after UV irradiation are shown in Figure 3-4. The XRD spectrum of the photocatalyst coating in Example 1 is shown in Figure 5. The diffuse reflection UV-visible light absorption spectrum of the photocatalyst coating in Example 1 is shown in Figure 6. The XPS peak diagrams of the photocatalyst coating before and after UV irradiation in Example 1 are shown in Figures 7-8. The ozone removal effect of the photocatalyst with different regeneration times in Example 1 is shown in Figure 9.

Example 2

An ozone decomposition photocatalyst coating, its preparation method includes the following steps:

(1) Soak the clean cotton fabric in 2.5mg/mL alkaline dopamine hydrochloride solution with pH=8.0, then take out the cotton fabric and irradiate it with UV for 20 minutes at an intensity of 800W to wrap the surface of the cotton fabric with an adhesive layer with a thickness of 30nm. ;

(2) Add AgNO ₃ to an ethanol aqueous solution with a volume concentration of 10%. The mass concentration of AgNO ₃ in the ethanol aqueous solution is 2.5%. Mix well to obtain mixed solution A;

(3) Add an ammonia solution with a mass concentration of 2% to the mixed solution A in step (2) dropwise until the precipitate at the bottom of the mixed solution A completely disappears to obtain the mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C. The molar ratio of silver ions to glucose in mixed solution C is 0.20:1; immerse the cotton treated in step (1) into mixed solution C. fabric, and perform ultrasonic treatment at 80°C for 7 minutes, ultrasonic power 100W, frequency 45kHz, then take out the cotton fabric and rinse with water; repeat the immersion, ultrasonic treatment, take out the cotton fabric, rinse with water 4 times, and finally put the cotton fabric at room temperature Vacuum drying under certain conditions;

(5) The dried cotton fabric in step (4) is irradiated with ultraviolet rays using a 365nm high-pressure mercury lamp for 15 minutes at an irradiation intensity of 1490W to obtain the product.

Example 3

An ozone decomposition photocatalyst coating, its preparation method includes the following steps:

(1) Soak the clean metal foam mesh in a mixed solution of 4 mg/mL silica sol and polysaccharide with pH = 9.0. The molar ratio of silica sol to polysaccharide is 1:8; then take out the metal foam mesh and perform UV irradiation for 16 minutes. The strength is 990W, and the surface of the foam metal mesh is wrapped with an adhesive layer with a thickness of 40nm; the pore size of the foam metal mesh is 300 μm;

(2) Add AgNO ₃ to an ethanol aqueous solution with a volume concentration of 10%. The mass concentration of AgNO ₃ in the ethanol aqueous solution is 2.5%. Mix well to obtain mixed solution A;

(3) Add an ammonia solution with a mass concentration of 2% to the mixed solution A in step (2) dropwise until the precipitate at the bottom of the mixed solution A completely disappears to obtain the mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C. The molar ratio of silver ions to glucose in mixed solution C is 0.18:1; immerse the foam treated in step (1) into mixed solution C. metal mesh, and perform ultrasonic treatment at 89°C for 7 minutes, ultrasonic power 100W, frequency 45kHz, then take out the foam metal mesh and rinse with water; repeat the immersion, ultrasonic treatment, take out the foam metal mesh, rinse with water 4 times, and finally remove the foam The metal mesh is vacuum dried at room temperature;

(5) The dry foam metal mesh in step (4) is irradiated with ultraviolet rays using a 365nm ultraviolet LED lamp for 15 minutes, and the irradiation intensity is 1490W.

Example 4

An ozone decomposition photocatalyst coating, its preparation method includes the following steps:

(1) Soak the clean sponge in a 2.1mg/mL tannic acid solution with pH=7.6, then take out the sponge and irradiate it with ultraviolet light for 25 minutes at an intensity of 600W to wrap the sponge surface with an adhesive layer with a thickness of 25nm;

(2) Add AgNO ₃ to an ethanol aqueous solution with a volume concentration of 12%. The mass concentration of AgNO ₃ in the ethanol aqueous solution is 3.4%. Mix well to obtain mixed solution A;

(3) Add an ammonia solution with a mass concentration of 2% to the mixed solution A in step (2) dropwise until the precipitate at the bottom of the mixed solution A completely disappears to obtain the mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C. The molar ratio of silver ions to glucose in mixed solution C is 0.18:1; immerse the sponge treated in step (1) into mixed solution C. , and perform ultrasonic treatment at 85°C for 7 minutes, ultrasonic power 100W, frequency 45kHz, then take out the sponge and rinse with water; repeat the immersion, ultrasonic treatment, take out the sponge, and rinse with water 4 times, and finally vacuum dry the sponge at room temperature. drying;

(5) UV-irradiate the sponge in step (4) using a 365nm UV LED lamp for 15 minutes with an irradiation intensity of 1490W to prepare the sponge.

Example 5

An ozone decomposition photocatalyst coating, its preparation method includes the following steps:

(1) Soak the clean cotton fabric in 3mg/mL alkaline dopamine hydrochloride solution with pH=8.5, then take out the cotton fabric and irradiate it with ultraviolet rays for 30 minutes at an irradiation intensity of 990W, so that the surface of the cotton fabric is wrapped with an adhesive layer with a thickness of 30nm;

(2) Add AgNO ₃ to an ethanol aqueous solution with a volume concentration of 10%. The mass concentration of AgNO ₃ in the ethanol aqueous solution is 2.1%. Mix well to obtain mixed solution A;

(3) Add an ammonia solution with a mass concentration of 2% to the mixed solution A in step (2) dropwise until the precipitate at the bottom of the mixed solution A completely disappears to obtain the mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C. The molar ratio of silver ions to glucose in mixed solution C is 0.24:1; immerse the cotton treated in step (1) into mixed solution C. fabric, and perform ultrasonic treatment at 85°C for 7 minutes, ultrasonic power 100W, frequency 45kHz, then take out the cotton fabric and rinse with water; repeat the immersion, ultrasonic treatment, take out the cotton fabric, rinse with water 4 times, and finally put the cotton fabric at room temperature Vacuum drying under certain conditions;

(5) The sponge in step (4) is irradiated with ultraviolet rays using a 365nm high-pressure mercury lamp for 15 minutes at an irradiation intensity of 1490W to prepare the sponge.

Example 6

An ozone decomposition photocatalyst coating, its preparation method includes the following steps:

(1) Soak the clean honeycomb activated carbon in a 3.5mg/mL alkaline tannic acid solution with pH=9.5, then take out the honeycomb activated carbon and conduct UV irradiation for 16 minutes with an irradiation intensity of 800W to coat the surface of the honeycomb activated carbon with an adhesive layer with a thickness of 20nm. layer;

(2) Add AgNO ₃ to an ethanol aqueous solution with a volume concentration of 11%. The mass concentration of AgNO ₃ in the ethanol aqueous solution is 2.1%. Mix well to obtain mixed solution A;

(3) Add an ammonia solution with a mass concentration of 2% to the mixed solution A in step (2) dropwise until the precipitate at the bottom of the mixed solution A completely disappears to obtain the mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C. The molar ratio of silver ions to glucose in mixed solution C is 0.20:1; immerse the honeycomb treated in step (1) into mixed solution C. Activated carbon, and ultrasonic treatment at 76°C for 7 minutes, ultrasonic power 100W, frequency 45kHz, then take out the honeycomb activated carbon, rinse with water; repeat the immersion, ultrasonic treatment, take out the honeycomb activated carbon, rinse with water 4 times, and finally put the honeycomb activated carbon at room temperature Vacuum drying under certain conditions;

(5) The sponge in step (4) is irradiated with ultraviolet rays using a 365nm high-pressure mercury lamp for 25 minutes at an irradiation intensity of 1490W to prepare the sponge.

Example 7

An ozone decomposition photocatalyst coating, its preparation method includes the following steps:

(1) Soak the clean metal foam mesh in 2.5 mg/mL alkaline dopamine hydrochloride solution with pH = 9.5, then take out the metal foam mesh and conduct UV irradiation for 25 minutes with an irradiation intensity of 800W to coat the honeycomb activated carbon surface with adhesive with a thickness of 40 nm. Connection layer; the pore size of the foam metal mesh is 300μm;

(2) Add AgNO ₃ to an ethanol aqueous solution with a volume concentration of 10%. The mass concentration of AgNO ₃ in the ethanol aqueous solution is 2.5%. Mix well to obtain mixed solution A;

(3) Add an ammonia solution with a mass concentration of 2% to the mixed solution A in step (2) dropwise until the precipitate at the bottom of the mixed solution A completely disappears to obtain the mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C. The molar ratio of silver ions to glucose in mixed solution C is 0.24:1; immerse the foam treated in step (1) into mixed solution C. metal mesh, and perform ultrasonic treatment at 76°C for 7 minutes, ultrasonic power 100W, frequency 45kHz, then take out the foam metal mesh and rinse with water; repeat immersion, ultrasonic treatment, take out the foam metal mesh, rinse with water 4 times, and finally remove the foam The metal mesh is vacuum dried at room temperature;

(5) The sponge in step (4) is irradiated with ultraviolet rays using a 365nm high-pressure mercury lamp for 25 minutes at an irradiation intensity of 1490W to prepare the sponge.

Comparative example 1

An ozone decomposition photocatalyst coating, its preparation method includes the following steps:

(1) Soak the clean metal foam mesh in a mixed solution of 4 mg/mL silica sol and polysaccharide with pH = 8.5, then take out the metal foam mesh and irradiate it with UV light for 30 minutes at an intensity of 1000W, so that the surface coating thickness of the metal foam mesh is 50nm adhesive layer;

(2) Add AgNO ₃ to an ethanol aqueous solution with a volume concentration of 8%. The mass concentration of AgNO ₃ in the ethanol aqueous solution is 1.8%. Mix well to obtain mixed solution A;

(3) Add an ammonia solution with a mass concentration of 2% to the mixed solution A in step (2) dropwise until the precipitate at the bottom of the mixed solution A completely disappears to obtain the mixed solution B;

(4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C. The molar ratio of silver ions to glucose in mixed solution C is 0.27:1; immerse the foam treated in step (1) into mixed solution C. metal mesh, and perform ultrasonic treatment at 60°C for 7 minutes, ultrasonic power 100W, frequency 45kHz, then take out the foam metal mesh and rinse with water; repeat the immersion, ultrasonic treatment, take out the foam metal mesh, rinse with water 4 times, and finally remove the foam The metal mesh is vacuum dried at room temperature;

(5) Use a 365nm UV LED lamp to irradiate the dry foam metal mesh in step (4) for 15 minutes with an irradiation intensity of 1000W to prepare it.

Comparative example 2

Taking the manganese photocatalyst used to remove ozone from tail gas as a comparative example, the photocatalyst is Pd/Mn/molecular sieve, in which the Pd content is 0.5wt% and the _MnO2 content is 14.5wt%.

Comparative example 3

Based on the preparation in Example 1, the ultraviolet irradiation in step (5) was not performed.

Performance Testing:

The photocatalyst coatings of Examples 1-7 and Comparative Examples 1-3 were tested for their catalytic decomposition of ozone performance. The test methods and conditions are as follows:

Test method: Pour ozone gas into a static reaction chamber set horizontally. An air inlet is set at the front end of the reaction chamber, and an ozone detector is connected to the tail outlet. Gases are arranged radially in the reaction chamber from front to back along the direction of air flow. Mixing channel, UV lamp group, photocatalyst coating plate and UV lamp group. There are 3 groups of photocatalyst coating plates. Each photocatalyst coating plate divides the reaction chamber into two small chambers with UV lamp groups at the front and rear. body, the wavelength of UV lamp is 365nm.

Control group: 365nm ultraviolet light decomposes ozone, visible light decomposes ozone, and 254nm ultraviolet light decomposes ozone.

Test Conditions:

The ozone concentration in the reaction gas is 40 ppm, the temperature is 25°C, and the relative humidity is 90%; the corresponding ozone decomposition rate after 5 minutes is recorded, as shown in Table 1.

Table 1 Ozone decomposition rate

Based on Examples 1-5, it can be seen that the ozone decomposition photocatalyst coating obtained by the preparation method of the ozone decomposition photocatalyst coating provided by the present invention has a very high catalytic effect, and the ozone decomposition rate can reach more than 99%, under better conditions. down to 100%. The ozone decomposition effect of Examples 6-7 has been reduced, but the decomposition rate can also reach more than 95%, indicating that the reaction temperature is an important influencing parameter for the synthesis of photocatalysts, and a higher reaction temperature can adjust the UV absorption range of the photocatalyst to be wider. It is well suited to 365nm ultraviolet light and can improve the ozone degradation rate of photocatalysts in humid environments. In Comparative Example 2-3, the ozone decomposition efficiency of ordinary manganese photocatalysts and coatings without hydrophobic treatment on the surface significantly decreased or even became deactivated in a high-humidity environment, indicating that the hydrophobic catalyst can resist the competitive adsorption of water molecules and improve the ozone decomposition ability. Through comparative experiments, it can be found that the method provided by the present invention can achieve excellent ozone decomposition efficiency under high humidity compared with photocatalysis alone.

Comparative data on the hydrophobic properties of the photocatalytic coatings prepared in the above examples and comparative examples are as follows in Table 2.

Table 2 Hydrophobic properties of photocatalytic coating

The coating adhesion refers to relevant standards: GB/T 1720-79 (89) "Determination of paint film adhesion (circle method)", GB/T9286-1998 "Cross-hatch test of paint and varnish films".

The coating water absorption rate refers to the relevant standards: GB/T 1738-1979 "Method for determination of water absorption rate of insulating paint films".

It can be seen from the above table that the wettability of the photocatalyst coatings in Examples 1-7 changed significantly after 365nm ultraviolet irradiation with a large specific surface area. After irradiation, the hydrophobic angles of the photocatalyst coatings were all at 150°. Above, it is proved that 365nm ultraviolet irradiation can significantly enhance the hydrophobicity of the coating; the reaction temperature in Comparative Example 1 is lower, and although the hydrophobic angle increases after irradiation, the increase is lower than that of Examples 1-7, proving that the reaction temperature will affect the photocatalyst The UV absorption intensity has a great influence on the hydrophobicity of the photocatalyst coating; Examples 6-7 compared with Comparative Example 1 show that the hydrophobicity can be improved by appropriately extending the UV irradiation time. Examples 1-7 and Comparative Example 1 have very low water absorption rates, both within 9%, while the ordinary manganese photocatalyst in Example 2 and Comparative Example 3 are both hydrophilic, with a water absorption rate exceeding 50%, indicating that the water absorption rate is Affected by the hydrophobicity of the coating.

For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all of these changes and modifications should fall within the protection scope of the claims of the present invention.

Claims (4)

1. An ozone decomposition photocatalyst coating, characterized in that it includes: a load material, an adhesive layer and a photocatalyst; The surface of the load material is wrapped with an adhesive layer; the photocatalyst is attached to the surface of the load material through the adhesive layer; The adhesive layer is one of a mixture of silica sol and polysaccharide, dopamine hydrochloride or tannic acid; the molar ratio of silica sol to polysaccharide in the mixture of silica sol and polysaccharide is 1:7-9; The photocatalyst is nanosilver; The ozone decomposition photocatalyst coating is prepared by the following method: (1) Soak the load material in the adhesive and adjust the pH of the adhesive, then take out the load material and irradiate it with ultraviolet light to wrap the surface of the load material with an adhesive layer; the adhesive is silica sol and polysaccharide. Mixed solution, dopamine hydrochloride or tannic acid; the concentration of the adhesive is 2-5mg/mL, the pH of the adhesive is 7.5-10.0, the intensity of UV light is 500-1000W, and the irradiation time is 15-35min. The thickness of the adhesive layer is 5-60nm; (2) Add AgNO ₃ to the ethanol aqueous solution and mix well to obtain mixed solution A; the volume concentration percentage of ethanol in the ethanol aqueous solution is 9-13%, and the mass concentration percentage of AgNO ₃ in the ethanol aqueous solution is 2-3.5%; (3) Add ammonia solution dropwise to mixed solution A in step (2) until the precipitate at the bottom of mixed solution A completely disappears to obtain mixed solution B; (4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C; immerse the load material treated in step (1) into mixed solution C, perform ultrasonic treatment, then take out the load material, rinse; repeat immersion, Ultrasonic treatment, removal of the loaded material, rinsing, and finally drying the loaded material; the molar ratio of silver ions to glucose in mixed solution C is 0.15-0.25:1, the temperature condition is 75-90°C; the ultrasonic treatment time is 6-12 minutes /Second-rate; (5) Irradiate the load material dried in step (4) with ultraviolet light to prepare a surface hydrophobic photocatalyst coating; the ultraviolet light wavelength is 365nm, the irradiation intensity is 500-1500W, and the irradiation time is 10-30 minutes. 2. The ozone decomposition photocatalyst coating according to claim 1, characterized in that the load material is one of foam metal mesh, cotton fabric, honeycomb activated carbon or sponge. 3. A method for preparing the ozone decomposition photocatalyst coating according to any one of claims 1-2, characterized in that it includes the following steps: (1) Soak the load material in the adhesive and adjust the pH of the adhesive, then take out the load material and irradiate it with ultraviolet light to wrap the surface of the load material with an adhesive layer; the adhesive is silica sol and polysaccharide. Mixed solution, dopamine hydrochloride or tannic acid; the concentration of the adhesive is 2-5mg/mL, the pH of the adhesive is 7.5-10.0, the intensity of UV light is 500-1000W, and the irradiation time is 15-35min. The thickness of the adhesive layer is 5-60nm; (2) Add AgNO ₃ to the ethanol aqueous solution and mix well to obtain mixed solution A; the volume concentration percentage of ethanol in the ethanol aqueous solution is 9-13%, and the mass concentration percentage of AgNO ₃ in the ethanol aqueous solution is 2-3.5%; (3) Add ammonia solution dropwise to mixed solution A in step (2) until the precipitate at the bottom of mixed solution A completely disappears to obtain mixed solution B; (4) Add glucose solution to mixed solution B in step (3) to obtain mixed solution C; immerse the load material treated in step (1) into mixed solution C, perform ultrasonic treatment, then take out the load material, rinse; repeat immersion, Ultrasonic treatment, removal of the loaded material, rinsing, and finally drying the loaded material; the molar ratio of silver ions to glucose in mixed solution C is 0.15-0.25:1, the temperature condition is 75-90°C; the ultrasonic treatment time is 6-12 minutes /Second-rate; (5) Irradiate the load material dried in step (4) with ultraviolet light to prepare a surface hydrophobic photocatalyst coating; the ultraviolet light wavelength is 365nm, the irradiation intensity is 500-1500W, and the irradiation time is 10-30 minutes. 4. The application of an ozone decomposition photocatalyst coating as claimed in any one of claims 1 to 2, characterized in that the ozone decomposition photocatalyst coating undergoes a reduction reaction under ultraviolet irradiation, through ultraviolet and nano-silver Synergistically decomposes ozone.