TiO2-containing air purifying agent and preparation method thereof

Abstract

The invention relates to the technical field of air purifying agents, in particular to a TiO2-containing air purifying agent and a preparation method thereof. The preparation method of the TiO2-containing air purifying agent comprises the following steps: uniformly mixing a titanium source, acetylacetone and polyethylene glycol, heating and stirring to obtain a titanium dioxide colloid; uniformly stirring cobalt nitrate hexahydrate and water, adding sodium oxalate and ammonia water, and stirring to obtain a solution; carrying out hydrothermal reaction, centrifugation, washing, drying and high-temperature calcination to obtain a cobalt oxide material; mixing the titanium dioxide colloid, the cobalt oxide material, a silane coupling agent and a cross-linking agent, and heating and stirring for reaction to obtain the TiO2-containing air purifying agent. The TiO2-containing air purifying agent prepared by the preparation method disclosed by the invention has a very good purifying effect on formaldehyde, methylbenzene and volatile organic compounds, and meanwhile, the purifying durability is relatively good.

Description

Technical Field

[0001] The present invention relates to the technical field of air purifying agents, and particularly relates to an air purifying agent containing TiO2 and a preparation method thereof. Background Art

[0002] In recent years, in order to meet the psychology of consumers, various green paints, glutinous rice adhesives, and furniture for maternal and child use have emerged on the market. These gimmicks sound reassuring, but in fact, toxic and harmful substances still exist. The difference is only the amount of harmful substances and the length of the emission time. After decoration, according to literature reports, the release period of formaldehyde is as long as 3 - 15 years. Volatile organic compounds, although the release period is short, are more harmful in the short term. If there are people with low immunity such as the elderly and infants in the family, longer ventilation time is required. In this era that requires high efficiency and speed, waiting for time is often the most unacceptable to the public. Therefore, various purification industries have emerged. Titanium dioxide (TiO2) photocatalyst is the most commonly used substance in the indoor environment purification industry. There are a wide variety of commercially available photocatalyst sprays, and there are also those that combine photocatalyst with activated carbon and apply them to the air purifier filter to play a role in purifying the air.

[0003] As an excellent semiconductor photocatalyst, TiO2 can be widely applied in fields such as wastewater treatment, air purification, disinfection, and medical protection under the radiation of sunlight. The excellent photochemical stability, reaction activity, and non-secondary pollution characteristics of TiO2 make it of great significance for sustainable development in the field of environmental governance, and it is also one of the nano-functional materials with the broadest application prospects for high efficiency, energy conservation, and environmental protection at present.

[0004] The structure of TiO2 mainly includes two types: crystalline and amorphous. Crystalline TiO2 exhibits high catalytic activity under light excitation, but the industrial preparation is complex, with a large amount of waste discharged, and the crystal form transformation requires long-term high-temperature calcination, resulting in high energy consumption. Compared with crystalline TiO2, amorphous TiO2 has poor catalytic activity due to structural defects, but the preparation energy consumption is low and the process is simple. According to classical physics theory, the band gap width of most semiconductors shows a negative correlation with temperature, that is, the band gap width decreases with the increase of temperature.

[0005] In the field of air purification, TiO2-based photocatalytic oxidation technology is considered a promising method for removing volatile organic compounds (VOCs) in the indoor environment. This technology can degrade indoor VOCs, even at low concentrations. However, limitations and disadvantages such as low visible light utilization efficiency, high charge recombination rate, low adsorption capacity for pollutants, formation of harmful by-products, and rapid deactivation have hindered the commercialization of this technology. Therefore, many studies are dedicated to developing modification methods, such as metal / non-metal doping, co-doping, coupling with other semiconductors, and integration with adsorbents, to overcome the above limitations.

[0006] To improve the performance of TiO2 photocatalysts, researchers have explored various modification methods. For example, the TiO2 composite material co-modified by MXene and quantum dots can significantly improve the separation efficiency of photo-generated carriers of TiO2 and enhance the photocatalytic activity. In addition, the preparation method of hollow nanostructured polyhedral TiO2 has also been developed, and the TiO2 prepared by this method has better ability to adsorb and degrade organic pollutants in industrial wastewater.

[0007] In summary, the preparation methods and modification technologies of TiO2 air purifying agents are an important research direction in chemical patents, aiming to improve the application effect of TiO2 in the field of air purification by improving its performance. Summary of the Invention

[0008] In view of the deficiencies in the above-mentioned prior art, the present invention provides an air purifying agent containing TiO2 and a preparation method thereof.

[0009] To solve the above technical problems, the technical solution adopted by the present invention is:

[0010] A preparation method of an air purifying agent containing TiO2, comprising the following steps:

[0011] S1. Mix the titanium source, acetylacetone, and polyethylene glycol evenly, heat and stir to obtain titanium dioxide colloid;

[0012] S2. Ultrasonically treat the above titanium dioxide colloid, add cobalt nitrate hexahydrate, silver nitrate, and water and stir evenly, then add sodium oxalate and ascorbic acid and stir to obtain a solution; carry out hydrothermal reaction, centrifuge, wash, dry, and calcine at high temperature to obtain silver-doped titanium dioxide-cobalt oxide material;

[0013] S3. Mix the above silver-doped titanium dioxide-cobalt oxide material, silane coupling agent, and crosslinking agent, heat and stir to react to obtain an air purifying agent containing TiO2.

[0014] TiO2 is an n-type semiconductor material that conducts electricity mainly through electrons. Its energy band structure is relatively special. The conduction band of TiO2 is composed of the lowest unoccupied molecular orbital (LUMO), and the valence band is composed of the highest occupied molecular orbital (HOMO). The band gap between the conduction band and the valence band is called the forbidden band, and the region between the two is called the forbidden band width. Its forbidden band width is 3.2 eV. When the incident photon energy is greater than the forbidden band width of titanium dioxide, the electrons in the valence band (VB) are excited by photons and then jump to the conduction band (CB), leaving holes in the VB. Generally speaking, photo-generated electrons and holes exist in two forms. One is recombination that occurs in the bulk or on the surface of the semiconductor material, that is, the photo-generated carriers are deactivated. The other is that photo-generated electrons and holes migrate to the surface of the catalyst respectively. Among them, photo-generated electrons have strong reducibility and can reduce the adsorbed oxygen around them to superoxide radicals (·O 2- ) with strong oxidation activity. Photo-generated holes have strong oxidizing properties and can oxidize the surrounding water / hydroxide ions into hydroxyl radicals (·OH). Under the combined action of ·O 2- and ·OH, the pollutants adsorbed on the surface of the catalyst can be decomposed into green and pollution-free small molecules such as CO2 and H2O.

[0015] However, the recombination rate of photo-generated carriers in the single-component titanium dioxide photocatalyst is relatively fast, resulting in a low photon utilization rate, thus reducing its catalytic activity. In addition, the forbidden band width of the TiO2 material is relatively wide (3.0 - 3.2 eV), and it only responds to ultraviolet light, resulting in a low sunlight utilization rate. Therefore, it is necessary to prepare a kind of

[0016] Silver-doped titanium dioxide can effectively enhance the photocatalytic activity of TiO2, which is 4.5 times and 2.3 times that of pure TiO2 under visible light and ultraviolet light conditions respectively. Therefore, in the present invention, silver is added to further enhance its catalytic activity.

[0017] Preferably, the preparation method of the air purifying agent containing TiO2 includes the following steps:

[0018] S1. Mix 8 - 14 parts by weight of titanium source, 60 - 120 parts by weight of absolute ethanol, 2 - 5 parts by weight of acetylacetone, and 1 - 2 parts by weight of polyethylene glycol evenly, adjust the pH to 3 - 4, stir at a temperature of 35 - 45 °C and 300 - 500 rpm for 1 - 4 h, and let it stand for 18 - 48 h to obtain titanium dioxide colloid;

[0019] S2. Ultrasonicate 30 - 50 parts by weight of titanium dioxide colloid at an ultrasonic power of 80 - 140 W and an ultrasonic frequency of 20 - 50 kHz for 15 - 30 min. Add 1 - 4 parts by weight of cobalt nitrate hexahydrate, 0.5 - 2 parts by weight of silver nitrate, and 60 - 120 parts by weight of water. Stir at 300 - 500 rpm for 20 - 50 min. Then add 0.3 - 1 part by weight of sodium oxalate and 1 - 3 parts by weight of ascorbic acid. Adjust the pH to 3.5 - 4.5. Carry out a hydrothermal reaction at 80 - 100 °C under a nitrogen atmosphere for 30 - 70 min. Filter by suction, wash, and dry. Then calcine at 850 - 1100 °C under a nitrogen atmosphere for 0.5 - 2 h to obtain a silver-doped titanium dioxide-cobalt oxide material;

[0020] S3. Mix 8 - 12 parts by weight of the above silver-doped titanium dioxide-cobalt oxide material and 1 - 3 parts by weight of a cross-linking agent. React at 55 - 70 °C and 300 - 500 rpm for 1 - 4 h. Filter by suction, wash, and dry to obtain an air purifier containing TiO2.

[0021] Cobalt oxide microspheres have a porous structure to increase their specific surface area. Through physical adsorption, the efficiency and service life of the air purifier can be improved. Cobalt oxide microspheres also have photocatalytic activity and can be used to degrade organic pollutants in the air. Their photocatalytic performance mainly benefits from their narrow bandgap (2.4 eV), which can effectively compensate for the bandgap of titanium dioxide, enabling the generation of photoinduced electron-hole pairs under visible light irradiation, and then catalyzing the decomposition of organic pollutants. Especially in the indoor environment, natural light can be used to activate the photocatalytic process. Therefore, combining silver-doped titanium dioxide with cobalt oxide can synergistically increase the air purification efficiency and photocatalytic efficiency.

[0022] More preferably, the preparation method of the air purifier containing TiO2 includes the following steps:

[0023] S1. Mix 8 - 14 parts by weight of a titanium source, 60 - 120 parts by weight of absolute ethanol, 2 - 5 parts by weight of acetylacetone, and 1 - 2 parts by weight of polyethylene glycol evenly. Adjust the pH to 3 - 4. Stir at a temperature of 35 - 45 °C and 300 - 500 rpm for 1 - 4 h. Let stand for 18 - 48 h to obtain a titanium dioxide colloid;

[0024] S2. Ultrasonically treat 30 - 50 parts by weight of titanium dioxide colloid at an ultrasonic power of 80 - 140 W and an ultrasonic frequency of 20 - 50 kHz for 15 - 30 min. Add 1 - 4 parts by weight of cobalt nitrate hexahydrate, 0.5 - 2 parts by weight of silver nitrate, and 60 - 120 parts by weight of water. Stir at 300 - 500 rpm for 20 - 50 min. Then add 0.3 - 1 part by weight of sodium oxalate and 1 - 3 parts by weight of ascorbic acid. Adjust the pH to 3.5 - 4.5. Conduct a hydrothermal reaction at 80 - 100 °C in a nitrogen atmosphere for 30 - 70 min. Filter by suction, wash, and dry. Then calcine at 850 - 1100 °C in a nitrogen atmosphere for 0.5 - 2 h to obtain a silver-doped titanium dioxide-cobalt oxide material;

[0025] S3. Mix 8 - 12 parts by weight of the above silver-doped titanium dioxide-cobalt oxide material, 1 - 3 parts by weight of negative ion powder, 2 - 4 parts by weight of silane coupling agent, and 1 - 3 parts by weight of crosslinking agent. React at 55 - 70 °C and 300 - 500 rpm for 1 - 4 h. Filter by suction, wash, and dry to obtain an air purifying agent containing TiO2.

[0026] Finally, as the most preferred embodiment, the inventors found that combining the silver-doped titanium dioxide-cobalt oxide material and the negative ion powder can further improve the effect. The silver-doped titanium dioxide-cobalt oxide material reacts with the negative ion powder, increasing the specific surface area of the adsorbent material. It can not only adsorb organic molecules such as formaldehyde but also decompose the adsorbed organic molecules into small molecules and simultaneously release negative ions beneficial to the human body. The negative ion powder achieves coagulation by transporting negative charges to dust, smoke, etc. in the air, thus achieving the effect of purifying the air.

[0027] The titanium source is any one of tetrabutyl titanate, isopropyl titanate, titanium tetrachloride, and titanium tetrabromide.

[0028] The negative ion powder is any one of tourmaline, monazite ore, and thorium dioxide.

[0029] The crosslinking agent is any one of trimethylolpropane trimethacrylate and amino crosslinking agent.

[0030] The coupling agent is any one of amino silane coupling agent and carboxyl silane coupling agent.

[0031] An air purifying agent containing TiO2 is obtained by using any one of the above preparation methods.

[0032] The air purifying agent containing TiO2 prepared by the present invention has the following advantages: Silver, as a dopant, can promote the separation of photo-generated electron-hole pairs, and can improve the photocatalytic activity of TiO2. In addition, silver doping can also reduce the band gap of TiO2, making it catalytically active under visible light, thereby improving the degradation efficiency of VOCs. Cobalt oxide is an effective oxidant, which can form a composite material with silver-doped titanium dioxide. Cobalt oxide can provide more active sites, enhance the adsorption capacity of the catalyst, and thus improve the adsorption and degradation efficiency of formaldehyde and VOCs. The negative ion powder can release negative ions, which can combine with pollutants in the air and cause them to settle, thereby purifying the air. Negative ions can also promote the combination of oxygen molecules and water molecules in the air to form hydroxyl radicals, which have strong oxidizing properties and can further degrade harmful substances in the air. By loading cobalt oxide and negative ion powder, the adsorption capacity of the TiO2 photocatalyst and the surface area of TiO2 are increased, the pollutants in the air purifying agent are stabilized and do not overflow, and at the same time, the contact area between TiO2 and pollutants is increased, facilitating the degradation of pollutants by the photocatalyst, thereby improving the degradation of pollutants by the purifying agent and improving the purification persistence.

[0033] In summary, the combination of silver-doped titanium dioxide, cobalt oxide and negative ion powder significantly improves the performance of the air purifying agent in adsorbing formaldehyde and VOCs by enhancing photocatalytic activity, adsorption capacity, promoting pollutant decomposition, enhancing antibacterial properties, and the synergistic effect of plasma and photocatalyst.

[0034] The beneficial effects of the present invention: 1. The present invention provides an air purifying agent containing TiO2 and its preparation method. Silver, as a dopant, can promote the separation of photo-generated electron-hole pairs and improve the photocatalytic activity of TiO2. In addition, silver doping can also reduce the band gap of TiO2, making it catalytically active under visible light, thereby improving the degradation efficiency of VOCs.

[0035] 2. Cobalt oxide is an effective oxidant, which can form a composite material with silver-doped titanium dioxide. Cobalt oxide can provide more active sites, enhance the adsorption capacity of the catalyst, and thus improve the adsorption and degradation efficiency of formaldehyde and VOCs.

[0036] 3. The negative ion powder can release negative ions, which can combine with pollutants in the air and cause them to settle, thereby purifying the air. Negative ions can also promote the combination of oxygen molecules and water molecules in the air to form hydroxyl radicals, which have strong oxidizing properties and can further degrade harmful substances in the air.

[0037] 4. The combination of silver-doped titanium dioxide-cobalt oxide and negative ion powder significantly improves the performance of the air purifier in adsorbing formaldehyde and VOCs by enhancing photocatalytic activity, adsorption capacity, promoting pollutant decomposition, enhancing antibacterial properties, and the synergistic effect of plasma and photocatalyst.

[0038] 5. The present invention improves the adsorption capacity of the TiO2 photocatalyst and the surface area of TiO2 by loading cobalt oxide and negative ion powder, stabilizes the pollutants in the air purifier without overflow, and at the same time increases the contact area between TiO2 and pollutants, facilitating the degradation of pollutants by the photocatalyst, thereby improving the degradation of pollutants by the purifier and enhancing the purification durability. Specific Embodiments

[0039] The following further describes in detail the above-mentioned inventive content of the present invention in conjunction with specific embodiments, but this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments.

[0040] Example 1

[0041] A preparation method of an air purifier containing TiO2 consists of the following steps:

[0042] S1. Mix 10 parts by weight of tetrabutyl titanate, 80 parts by weight of absolute ethanol, 3 parts by weight of acetylacetone, and 1.3 parts by weight of polyethylene glycol (PEG-4000) evenly, adjust the pH to 3.5, stir at 40°C and 400 rpm for 2 h, and let stand for 24 h to obtain titanium dioxide colloid.

[0043] S2. At room temperature, ultrasonically treat 40 parts by weight of the titanium dioxide colloid at an ultrasonic power of 100 W and an ultrasonic frequency of 40 kHz for 20 min, add 2 parts by weight of cobalt nitrate hexahydrate, 1 part by weight of silver nitrate, and 80 parts by weight of water, stir at 400 rpm for 30 min, then add 0.5 part by weight of sodium oxalate and 2 parts by weight of ascorbic acid, adjust the pH to 4, carry out a hydrothermal reaction at 90°C for 40 min under a nitrogen atmosphere, filter, wash, dry, and then calcine at 950°C for 1 h under a nitrogen atmosphere to obtain silver-doped titanium dioxide-cobalt oxide material.

[0044] S3. Mix 10 parts by weight of the above silver-doped titanium dioxide-cobalt oxide material, 1.5 parts by weight of tourmaline, 3 parts by weight of diethylenetriaminepropyltrimethoxysilane, and 2 parts by weight of trimethylolpropane trimethacrylate, react at 60°C and 400 rpm for 2 h, filter, wash, and dry to obtain an air purifier containing TiO2.

[0045] Example 2

[0046] A preparation method of an air purifier containing TiO2 consists of the following steps:

[0047] S1. Mix 8 parts by weight of tetrabutyl titanate, 60 parts by weight of absolute ethanol, 2 parts by weight of acetylacetone, and 1 part by weight of polyethylene glycol (PEG-4000) evenly, adjust the pH to 3, stir at a temperature of 35°C and 300 rpm for 1 h, and let it stand for 18 h to obtain titanium dioxide colloid;

[0048] S2. At room temperature, ultrasonically treat 30 parts by weight of titanium dioxide colloid at an ultrasonic power of 80 W and an ultrasonic frequency of 20 kHz for 15 min, add 1 part by weight of cobalt nitrate hexahydrate, 0.5 part by weight of silver nitrate, and 60 parts by weight of water, stir at 300 rpm for 20 min, then add 0.3 part by weight of sodium oxalate and 1 part by weight of ascorbic acid, adjust the pH to 3.5, carry out a hydrothermal reaction at 80°C for 30 min under a nitrogen atmosphere, filter by suction, wash, dry, and then calcine at 850°C for 0.5 h under a nitrogen atmosphere to obtain silver-doped titanium dioxide-cobalt oxide material;

[0049] S3. Mix 8 parts by weight of the above silver-doped titanium dioxide-cobalt oxide material, 1 part by weight of tourmaline, 2 parts by weight of diethylenetriaminepropyltrimethoxysilane, and 1 part by weight of trimethylolpropane trimethacrylate, react at 55°C and 300 rpm for 1 h, filter by suction, wash, dry to obtain an air purifying agent containing TiO2.

[0050] Example 3

[0051] A preparation method of an air purifying agent containing TiO2, which consists of the following steps:

[0052] S1. Mix 14 parts by weight of tetrabutyl titanate, 120 parts by weight of absolute ethanol, 5 parts by weight of acetylacetone, and 2 parts by weight of polyethylene glycol (PEG-4000) evenly, adjust the pH to 4, stir at a temperature of 45°C and 500 rpm for 4 h, and let it stand for 48 h to obtain titanium dioxide colloid;

[0053] S2. At room temperature, ultrasonically treat 50 parts by weight of titanium dioxide colloid at an ultrasonic power of 140 W and an ultrasonic frequency of 50 kHz for 30 min, add 4 parts by weight of cobalt nitrate hexahydrate, 2 parts by weight of silver nitrate, and 120 parts by weight of water, stir at 500 rpm for 50 min, then add 1 part by weight of sodium oxalate and 3 parts by weight of ascorbic acid, adjust the pH to 4.5, carry out a hydrothermal reaction at 100°C for 70 min under a nitrogen atmosphere, filter by suction, wash, dry, and then calcine at 1100°C for 2 h under a nitrogen atmosphere to obtain silver-doped titanium dioxide-cobalt oxide material;

[0054] S3 mixes 12 parts by weight of the above silver-doped titanium dioxide-cobalt oxide material, 3 parts by weight of tourmaline, 4 parts by weight of diethylenetriaminepropyltrimethoxysilane, and 4 parts by weight of trimethylolpropane trimethacrylate, reacts at 70 °C and 500 rpm for 4 h, performs suction filtration, washing, and drying to obtain an air purifying agent containing TiO2.

[0055] Comparative Example 1

[0056] A preparation method of an air purifying agent containing TiO2 comprises the following steps:

[0057] S1. Mix 10 parts by weight of tetrabutyl titanate, 80 parts by weight of absolute ethanol, 3 parts by weight of acetylacetone, and 1.3 parts by weight of polyethylene glycol (PEG-4000) evenly, adjust the pH to 3.5, stir at a temperature of 40 °C and 400 rpm for 2 h, and let stand for 24 h to obtain a titanium dioxide colloid;

[0058] S2. At room temperature, ultrasonically irradiate 40 parts by weight of the titanium dioxide colloid at an ultrasonic power of 100 W and an ultrasonic frequency of 20 kHz for 20 min, add 1 part by weight of silver nitrate and 80 parts by weight of water, stir at 400 rpm for 30 min, then add 2 parts by weight of ascorbic acid, adjust the pH to 4, perform a hydrothermal reaction at 90 °C for 40 min under a nitrogen atmosphere, perform suction filtration, washing, and drying, and then calcine at 950 °C for 1 h under a nitrogen atmosphere to obtain an air purifying agent containing TiO2.

[0059] Comparative Example 2

[0060] A preparation method of an air purifying agent containing TiO2 comprises the following steps:

[0061] S1. Mix 10 parts by weight of tetrabutyl titanate, 80 parts by weight of absolute ethanol, 3 parts by weight of acetylacetone, and 1.3 parts by weight of polyethylene glycol (PEG-4000) evenly, adjust the pH to 3.5, stir at a temperature of 40 °C and 400 rpm for 2 h, and let stand for 24 h to obtain a titanium dioxide colloid;

[0062] S2. At room temperature, ultrasonically irradiate 40 parts by weight of the titanium dioxide colloid at an ultrasonic power of 100 W and an ultrasonic frequency of 20 kHz for 20 min, add 2 parts by weight of cobalt nitrate hexahydrate, 1 part by weight of silver nitrate and 80 parts by weight of water, stir at 400 rpm for 30 min, then add 0.5 part by weight of sodium oxalate and 2 parts by weight of ascorbic acid, adjust the pH to 4, perform a hydrothermal reaction at 90 °C for 40 min under a nitrogen atmosphere, perform suction filtration, washing, and drying, and then calcine at 950 °C for 1 h under a nitrogen atmosphere to obtain an air purifying agent containing TiO2.

[0063] Comparative Example 3

[0064] A preparation method of an air purifying agent containing TiO2, which consists of the following steps:

[0065] S1. Mix 10 parts by weight of tetrabutyl titanate, 80 parts by weight of absolute ethanol, 3 parts by weight of acetylacetone, and 1.3 parts by weight of polyethylene glycol (PEG-4000) evenly, adjust the pH to 3.5, stir at 40 °C and 400 rpm for 2 h, and let stand for 24 h to obtain titanium dioxide colloid;

[0066] S2. At room temperature, ultrasonically irradiate 40 parts by weight of the titanium dioxide colloid at an ultrasonic power of 100 W and an ultrasonic frequency of 20 kHz for 20 min, add 2 parts by weight of cobalt nitrate hexahydrate and 80 parts by weight of water, stir at 400 rpm for 30 min, then add 0.5 part by weight of sodium oxalate and 2 parts by weight of ascorbic acid, adjust the pH to 4, carry out hydrothermal reaction at 90 °C for 40 min under a nitrogen atmosphere, filter by suction, wash, dry, and then calcine at 950 °C for 1 h under a nitrogen atmosphere to obtain the air purifying agent containing TiO2.

[0067] Comparative Example 4

[0068] A preparation method of an air purifying agent containing TiO2, which consists of the following steps:

[0069] S1. Mix 10 parts by weight of tetrabutyl titanate, 80 parts by weight of absolute ethanol, 3 parts by weight of acetylacetone, and 1.3 parts by weight of polyethylene glycol (PEG-4000) evenly, adjust the pH to 3.5, stir at 40 °C and 400 rpm for 2 h, and let stand for 24 h to obtain titanium dioxide colloid;

[0070] S2. Mix 40 parts by weight of the above-mentioned titanium dioxide colloid, 1.5 parts by weight of tourmaline, 3 parts by weight of diethylenetriaminepropyltrimethoxysilane, and 2 parts by weight of trimethylolpropane trimethacrylate, react at 60 °C and 400 rpm for 2 h, filter by suction, wash, dry, to obtain the air purifying agent containing TiO2.

[0071] Test Example 1

[0072] Air purification performance test: The test is carried out in accordance with the national light industry standard QB / T 2761-2006 "Determination Method for Purification Effect of Indoor Air Purification Products". Set up an experimental chamber and a blank control chamber. The blank control chamber is a base paper without applying the air purifying agent containing TiO2, and the experimental chamber is a base paper coated with the air purifying agent containing TiO2 according to the standard. The samples are prepared according to the preparation of the samples in Section 5. Take 100 g each of the air purifying agents containing TiO2 obtained in Examples 1-3 and Comparative Examples 1-4, add water to make a paste, and spray them respectively with a small spray pump on 1 m 3On both the front and back sides of the base paper, spraying is carried out by means of multiple spraying-drying-spraying. Under natural light, the treatment capabilities of the air purifying agents containing TiO2 in Examples 1-3 and Comparative Examples 1-4 for formaldehyde, total organic compounds, and toluene pollutants are tested. Five groups of parallel tests are conducted, and the average value is taken.

[0073] Table 1 Purification effects of the air purifying agents containing TiO2

[0074]

[0075] Test Example 2

[0076] Purification persistence of formaldehyde and toluene: According to the standard JC / T 1074-2008 "Purification Performance of Indoor Air Purifying Functional Coating Materials", the purification persistence of formaldehyde and toluene for the examples and comparative examples is tested, and the results are shown in Table 2.

[0077] Table 2 Test results of purification persistence of formaldehyde and toluene

[0078] Formaldehyde purification persistence (%) Toluene purification persistence (%) Example 1 88.1 86.2 Example 2 87.2 80.8 Example 3 86.5 81.2 Comparative Example 1 57.3 54.1 Comparative Example 2 75.1 77.7 Comparative Example 3 70.4 71.9 Comparative Example 4 72.6 73.4

[0079] From the above results, it can be seen that the air purifying agent containing TiO2 prepared by the present invention has good purification effects on formaldehyde, toluene, and volatile organic compounds, and at the same time has good purification persistence. From Examples 1 and Comparative Examples 1-4, it can be seen that silver-doped titanium dioxide can effectively enhance the photocatalytic activity of TiO2. Due to its porous structure, cobalt oxide microspheres can increase their specific surface area, and the efficiency and service life of the air purifying agent can be improved through physical adsorption. Cobalt oxide microspheres also have photocatalytic activity and can be used to degrade organic pollutants in the air. Its photocatalytic performance mainly benefits from its narrow bandgap (2.4 eV), which can effectively make up for the bandgap of titanium dioxide, enabling it to generate photoinduced electrons and holes under visible light irradiation, and then catalyze the decomposition of organic pollutants. Especially in the indoor environment, natural light can be used to activate the photocatalytic process. Therefore, the combined use of silver-doped titanium dioxide and cobalt oxide can synergistically increase the air purification efficiency and photocatalytic efficiency.

[0080] Cobalt oxide microspheres have a porous structure to increase their specific surface area, and the efficiency and service life of air purifiers can be improved through physical adsorption. Cobalt oxide microspheres also have photocatalytic activity and can be used to degrade organic pollutants in the air. Their photocatalytic performance mainly benefits from their narrow bandgap (2.4 eV), which can effectively compensate for the bandgap of titanium dioxide, enabling the generation of photoinduced electron-hole pairs under visible light irradiation, and then catalyzing the decomposition of organic pollutants. Especially in the indoor environment, natural light can be used to activate the photocatalytic process. Therefore, the combination of silver-doped titanium dioxide and cobalt oxide can synergistically increase the air purification efficiency and photocatalytic efficiency. Negative ions can also promote the combination of oxygen molecules and water molecules in the air to form hydroxyl radicals, which have strong oxidizing properties and can further degrade harmful substances in the air. By loading cobalt oxide and negative ion powder, the adsorption capacity of the TiO2 photocatalyst and the surface area of TiO2 are increased, stabilizing the pollutants in the air purifier without spillage. At the same time, the contact area between TiO2 and pollutants is increased, facilitating the degradation of pollutants by the photocatalyst, thereby improving the degradation of pollutants by the purifier and enhancing the purification durability.

[0081] In summary, the combination of silver-doped titanium dioxide-cobalt oxide and negative ion powder significantly improves the performance of air purifiers in adsorbing formaldehyde and VOCs by enhancing photocatalytic activity, adsorption capacity, promoting pollutant decomposition, enhancing antibacterial properties, and the synergistic effect of plasma and photocatalyst.

Claims

1. A method for preparing an air purifier containing TiO2, characterized in that: The steps include: S1, mixing titanium source, acetylacetone and polyethylene glycol uniformly, heating and stirring to obtain titanium dioxide colloid; S2, subjecting the titanium dioxide colloid to ultrasonic treatment, adding cobalt nitrate hexahydrate and water to stir evenly, and then adding sodium oxalate and ascorbic acid to stir to obtain a solution; performing a hydrothermal reaction, centrifuging, washing, drying, and calcining at high temperature to obtain a titanium dioxide-cobalt oxide material; S3: Mix the titanium dioxide-cobalt oxide material, silane coupling agent and cross-linking agent, heat and stir to react, and obtain an air purifier containing TiO2.

2. The method for preparing an air purifier containing TiO2 according to claim 1, characterized in that: The following steps are involved: S1, mixing titanium source, acetylacetone and polyethylene glycol uniformly, heating and stirring to obtain titanium dioxide colloid; S2, subjecting the titanium dioxide colloid to ultrasonic treatment, adding cobalt nitrate hexahydrate, silver nitrate and water and stirring evenly, then adding sodium oxalate and ascorbic acid and stirring to obtain a solution; performing a hydrothermal reaction, centrifuging, washing, drying, and calcining at high temperature to obtain a silver-doped titanium dioxide-cobalt oxide material; S3: mixing the silver-doped titanium dioxide-cobalt oxide material and the cross-linking agent, heating and stirring to react, and obtaining an air purifier containing TiO2.

3. The method for preparing an air purifier containing TiO2 according to claim 1 or 2, characterized in that: The following steps are involved: S1, mixing titanium source, acetylacetone and polyethylene glycol uniformly, heating and stirring to obtain titanium dioxide colloid; S2, subjecting the titanium dioxide colloid to ultrasonic treatment, adding cobalt nitrate hexahydrate, silver nitrate and water and stirring evenly, then adding sodium oxalate and ascorbic acid and stirring to obtain a solution; performing a hydrothermal reaction, centrifuging, washing, drying, and calcining at high temperature to obtain a silver-doped titanium dioxide-cobalt oxide material; S3: mixing the silver-doped titanium dioxide-cobalt oxide material, negative ion powder, silane coupling agent and cross-linking agent, heating and stirring to react, and obtaining an air purifier containing TiO2.

4. The method for preparing an air purifier containing TiO2 according to claim 3, characterized in that: The titanium source is any one of tetrabutyl titanate, isopropyl titanate, titanium tetrachloride and titanium tetrabromide.

5. The method for preparing an air purifier containing TiO2 according to claim 3, characterized in that: The negative ion powder is any one of tourmaline, monazite ore and thorium dioxide.

6. The method for preparing an air purifier containing TiO2 according to claim 3, characterized in that: The crosslinking agent is any one of trimethylolpropane trimethacrylate and amino crosslinking agent.

7. The method for preparing an air purifier containing TiO2 according to claim 3, characterized in that: The coupling agent is any one of an amino silane coupling agent and a carboxyl silane coupling agent.

8. The method for preparing an air purifier containing TiO2 according to claim 3, characterized in that: The hydrothermal reaction temperature in S2 is 80-100° C., and the hydrothermal reaction time is 30-70 min; the high-temperature calcination temperature is 850-1100° C., and the calcination time is 0.5-2 h.

9. The method for preparing an air purifier containing TiO2 according to claim 3, characterized in that: The heating temperature in S3 is 55-70° C., the stirring speed is 300-500 rpm, and the reaction time is 1-4 h.

10. An air purifier containing TiO2, obtained by the preparation method according to any one of claims 1 to 9.

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