High-purity spherical zinc oxide-silica synergistic photocatalytic air purification material

Abstract

This invention belongs to the field of air purification materials technology, specifically relating to a high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material. By weight, it comprises 100 parts of silica-coated high-purity spherical zinc oxide, 1-3 parts of a silanized porphyrin trifluoromethyl functional polymer, 2400-2950 parts of ethanol, 101.5-204 parts of deionized water, and 0.006-0.06 parts of glacial acetic acid. The high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material prepared by this invention exhibits improved interface stability, a broadened spectral response range, and pollutant degradation capabilities.

Description

[0001] This invention belongs to the field of air purification materials technology, specifically relating to a high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material. Background Technology

[0002] With rapid industrial development and improved living standards, air pollution has become increasingly severe. Acid rain caused by nitrogen oxides and sulfur oxides corrodes buildings and damages the ecosystem; photochemical smog reduces atmospheric visibility and irritates the respiratory tract; indoor pollutants such as formaldehyde pose long-term health risks, inducing diseases such as cancer. Traditional air purification methods, such as physical adsorption, are prone to saturation, and chemical absorption is prone to secondary pollution. Photocatalysis, using semiconductors as catalysts and solar energy to drive reactions that degrade pollutants, is green, environmentally friendly, and sustainable, making it a hot topic in air purification research. Among these, zinc oxide, due to its suitable bandgap and strong oxidizing properties, can effectively degrade pollutants such as nitrogen oxides, sulfur oxides, and formaldehyde. Traditional zinc oxide suffers from numerous crystal defects, resulting in problems such as easy recombination of photogenerated carriers and poor stability; while high-purity spherical zinc oxide, although having fewer crystal defects and a lower carrier recombination rate, still faces issues such as lack of visible light response and susceptibility to interface erosion by pollutants leading to activity decay. In existing technologies, the core function of zinc oxide and silicon dioxide composites is to improve the dispersibility and stability of materials, such as preventing agglomeration and resisting acids and alkalis. However, they cannot solve the problems of insufficient visible light response and further optimization of carrier separation efficiency, resulting in low utilization of the solar spectrum and insufficient reaction probability when degrading low-concentration air pollutants such as formaldehyde and toluene, making it difficult to meet actual air purification needs.

[0003] However, current research on zinc oxide and silica composite photocatalytic air purification materials faces the following challenges: Zinc oxide has a large band gap and no visible light response, resulting in low utilization of the solar spectrum; photogenerated electrons and holes easily recombine, leading to low quantum efficiency and reduced opportunities for photogenerated electrons and holes to participate in photocatalytic reactions. For example, when degrading pollutants such as formaldehyde and nitrogen oxides in the air, the lack of sufficient electrons and holes to initiate redox reactions slows down the degradation rate of pollutants, reduces photocatalytic activity, and consequently affects the performance of zinc oxide as a photocatalyst in practical applications. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention provides a high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material. By designing a silanized porphyrin trifluoromethyl functional polymer, it can improve the stability of the spherical zinc oxide-silica interface, enhance visible light utilization efficiency, and improve photocatalytic performance.

[0005] The technical solution for achieving the objective of this invention is as follows:

[0006] A high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material, by weight, comprises 100 parts of high-purity spherical zinc oxide coated with silica and 1-3 parts of silanized porphyrin trifluoromethyl functional polymer.

[0007] The high-purity spherical zinc oxide refers to spherical zinc oxide with a purity of ≥99.9%.

[0008] The method for preparing the silica-coated high-purity spherical zinc oxide includes the following steps:

[0009] High-purity spherical zinc oxide slurry was sonicated for 25–35 min, and then ammonia was added dropwise with stirring to adjust the pH to 8–10. The system was then heated to 60–70 °C. An ethanol solution of tetraethyl silicate was placed in a constant-pressure dropping funnel and added dropwise at 1 drop / second with stirring at 600–800 rpm to the high-purity spherical zinc oxide system. The addition time was controlled within 1.5–2 h. After the addition was completed, the reaction was continued for 4–6 h. After the reaction was completed, heating was stopped, and the mixture was aged at room temperature at 200–300 rpm for 6–12 h. The product was separated by centrifugation and washed 3–4 times with anhydrous ethanol and deionized water until the conductivity of the supernatant was ≤5 μS / cm. The washed product was vacuum dried at 75–80 °C for 6–12 h to obtain silica-coated high-purity spherical zinc oxide.

[0010] The high-purity spherical zinc oxide slurry contains 20% to 30% spherical zinc oxide by mass; the solvent of the slurry is a mixed solution of ethanol and water with a volume ratio of 4:1.

[0011] The amount of tetraethyl silicate added in the tetraethyl silicate ethanol solution is 2% to 5% relative to the mass of high-purity spherical zinc oxide; the molar ratio of tetraethyl silicate to ethanol in the tetraethyl silicate ethanol solution is 1:(8 to 15); and the concentration of the tetraethyl silicate ethanol solution is 1.1 to 2.1 mol / L.

[0012] When the ethanol solution of tetraethyl silicate is added dropwise to the above-mentioned high-purity spherical zinc oxide system, 0.1-0.3 mol / L ammonia water needs to be added to maintain the pH at 8-10.

[0013] The silanized porphyrin trifluoromethyl functional polymer is copolymerized from vinyl porphyrin imine compound, 4-trifluoromethylstyrene and vinyl compound free radicals.

[0014] The preparation method of the silanized porphyrin trifluoromethyl functional polymer includes the following steps:

[0015] Weigh out the vinyl porphyrinimide compound, 4-trifluoromethylstyrene, and vinyl compound in a molar ratio of 1:(2-5):(6-10). First, dissolve the vinyl porphyrinimide compound, 4-trifluoromethylstyrene, and an initiator in toluene at a molar ratio of 0.01-0.015 relative to the vinyl porphyrinimide compound. Then, place the solution in an ice bath and cycle it three times under vacuum and nitrogen. Afterward, carry out free radical polymerization at 65-75°C under a nitrogen atmosphere for 3-4 hours. Then, add the vinyl compound and an initiator at a molar ratio of 0.004-0.006 relative to the vinyl porphyrinimide compound and react for another 4-5 hours. After cooling the reaction mixture to room temperature, add it dropwise to a mixture of cold n-hexane and methanol equivalent to 10 times the volume of the reaction liquid to precipitate the product. Centrifuge and then... The solid was dissolved in dichloromethane and added dropwise to 10 times its volume of cold n-hexane to precipitate. After centrifugation, the solid was dried under vacuum at 40°C for 10–12 h to constant weight to obtain the porphyrin functional polymer. The functional polymer was dissolved in anhydrous toluene in a Shrek flask and circulated under vacuum and nitrogen three times. Freshly distilled epoxy silane coupling agent was slowly added under nitrogen atmosphere with stirring, and the reaction was carried out at 25–30°C in the dark for 24–48 h. The reaction solution was concentrated under reduced pressure to one-fifth of its original volume. The concentrate was slowly added dropwise to cold n-hexane with vigorous stirring to precipitate. After centrifugation, the solid was dissolved in dichloromethane and added dropwise to cold n-hexane again. After centrifugation, the precipitate was collected. This process was repeated 2–3 times. Finally, the precipitate was dried under vacuum at 40°C for 20–24 h to obtain the silanized porphyrin trifluoromethyl functional polymer.

[0016] The preparation method of the silanized porphyrin trifluoromethyl functional polymer adopts a stepwise addition of initiator and monomer. First, a vinyl porphyrin imine compound with low activity and 4-trifluoromethylstyrene are polymerized. The initial amount of initiator is 0.01 to 0.015 times the molar amount of vinyl porphyrin imine compound to ensure that the two monomers react fully. Then, a vinyl compound with higher activity is added, and an initiator of 0.004 to 0.006 times the molar amount of vinyl porphyrin imine compound is added to avoid premature polymerization of vinyl compound due to excessive initiator in the early stage. Finally, the molecular weight distribution coefficient of the polymer is controlled to be 1.2 to 1.5 to ensure the stability of material properties.

[0017] The vinyl compound is selected from one or both of 4-methylstyrene and styrene.

[0018] The initiator is selected from azobisisobutyronitrile.

[0019] The ratio of the solid to dichloromethane is 1g of solid to 10mL of dichloromethane.

[0020] The cold hexane and methanol mixture is a cold hexane and methanol mixture with a volume ratio of 3:1.

[0021] The amount of the epoxy-based silane coupling agent added is 3 to 5 times the molar amount of porphyrin amino.

[0022] The method for preparing the vinylporphyrin imine compound includes the following steps:

[0023] Place 1.0 eq of 5,10,15,20-tetra(4-aminophenyl)porphyrin in a Shrek flask, deoxygenate and purge with nitrogen, add anhydrous dichloromethane, and stir to dissolve. Then add 1.05–1.25 times the amount of 5,10,15,20-tetra(4-aminophenyl)porphyrin dissolved in anhydrous dichloromethane, and place the solution in a constant pressure dropping funnel. Finally, add 0.02–1.25 molar amounts of 5,10,15,20-tetra(4-aminophenyl)porphyrin. 0.05 times the volume of dried p-toluenesulfonic acid was added to the reaction flask. Under nitrogen protection and in the dark, a dichloromethane solution of p-vinylbenzaldehyde was slowly added dropwise, and the reaction was stirred for 3-5 hours. After the reaction was completed, the reaction solution was placed in an ice bath. 20-50 mg of sodium bicarbonate solid was added in batches to the reaction solution until the pH reached 7-8. The solution was then filtered, dried with anhydrous sodium sulfate, filtered again, concentrated under reduced pressure at 25-35°C, and purified by neutral alumina column chromatography to obtain the vinylporphyrin imine compound.

[0024] In the preparation method of the vinylporphyrin imine compound, if the pH of the system is <5 after adding p-toluenesulfonic acid, 4-5 mg of sodium bicarbonate per mole of porphyrin should be added to avoid protonation of the porphyrin ring.

[0025] Specifically, the p-vinylbenzaldehyde needs to be purified by vacuum distillation before use, and 0.1% hydroquinone is added to inhibit polymerization.

[0026] Specifically, the slow addition of a dichloromethane solution of p-vinylbenzaldehyde takes a total time of >1 hour.

[0027] A method for preparing a high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material includes the following steps:

[0028] S1. Add 100 parts of high-purity spherical zinc oxide coated with silica to a mixed solution of 2000-3000 parts of ethanol and 100-200 parts of water, and sonicate for 25-35 minutes to form a uniform suspension.

[0029] S2. Adjust the pH of the suspension to 6-7 with a mixture of 0.006-0.06 parts glacial acetic acid and 1-3 parts deionized water, heat to 60-70℃, and stir at 600-800 rpm;

[0030] S3. Dissolve 1-3 parts of silanized porphyrin trifluoromethyl functional polymer in 400-450 parts of ethanol, add 0.5-1 parts of deionized water, stir evenly, pre-hydrolyze at room temperature for 20-30 min, then sonicate for 10-20 min to ensure dispersion, put into a constant pressure dropping funnel, and add it to the system described in S2 at a rate of 1-3 drops / second, while maintaining the rotation speed at 600-800 rpm;

[0031] S4. After the addition is complete, continue stirring at 60-70℃ for 4-6 hours, and then age at room temperature at 50-80 rpm for 6-12 hours.

[0032] S5. Centrifuge the product and wash it alternately with anhydrous ethanol and deionized water 3-4 times until the conductivity of the supernatant is ≤5μS / cm; dry the washed product under vacuum at 75-80℃ for 6-12h to obtain high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material.

[0033] Beneficial effects

[0034] This invention provides a high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material. By designing a silanized porphyrin trifluoromethyl functional polymer, the air purification material of this invention exhibits the following beneficial effects:

[0035] 1. Improved interface stability: The silica coating layer effectively protects the zinc oxide core, while the silanized porphyrin trifluoromethyl functional polymer is linked to the silica through chemical bonds, making it less prone to detachment and loss. This helps to extend the service life of the material and reduce the frequency of replacement and operating costs.

[0036] 2. Broadening the spectral response range and improving solar energy utilization: After absorbing visible light in the 400–700 nm range in silanized porphyrin trifluoromethyl functional polymers, electrons in the porphyrin ring transition from the ground state HOMO to the excited state LUMO. Since the porphyrin LUMO is higher than the low energy level of the zinc oxide conduction band, excited-state electrons can spontaneously inject into the zinc oxide conduction band. Simultaneously, strong oxidizing holes are formed in the porphyrin HOMO. Electrons injected into the zinc oxide conduction band can participate in reduction reactions. Holes on the porphyrin ring can directly oxidize pollutants or form hydroxyl radicals by oxidizing surface hydroxyl groups, thereby achieving a visible-light-responsive photocatalytic process. Furthermore, the excited state of the porphyrin can activate ambient oxygen into singlets through energy transfer pathways. For the process of generating oxygen in a triplet state, the energy matching condition must be met, meaning the energy of the triplet state of the porphyrin must be higher than the energy difference for the oxygen molecule to transition from the triplet ground state to the singlet state. Therefore, this energy transfer process is thermodynamically feasible. Alternatively, it can generate reactive oxygen species such as superoxide radicals through electron transfer pathways, which can jointly assist in the degradation of low-concentration formaldehyde. At the same time, the silica coating layer, as an insulating medium, although it cannot provide a fast charge separation channel, can block the adsorption of impurity molecules such as water and pollutants in the external environment on the zinc oxide surface through physical isolation, thereby inhibiting the formation of additional recombination centers and protecting the zinc oxide core from photocorrosion, thus indirectly helping to maintain the lifetime of photogenerated carriers.

[0037] 3. Pollutant degradation ability: The trifluoromethyl group on the polymer side chain is a strong electron-withdrawing group, which can significantly reduce the electron cloud density of the porphyrin ring and enhance the oxidation ability of photogenerated holes, thereby improving the efficiency of hole oxidation of pollutants. At the same time, the introduction of trifluoromethyl enhances the hydrophobicity of the polymer, which may enrich low polar volatile organic compounds through weak polar interactions, increase their local concentration on the catalyst surface, and thus increase the probability of reaction with photoactive species.

[0038] In summary, this invention integrates four major functions: visible light capture, ultraviolet response and charge generation, interface stabilization and protection, and pollutant degradation. Through the multi-dimensional synergistic effect between components, the material is endowed with stable and broad-spectrum air purification properties. Attached Figure Description

[0039] Figure 1 This is a synthetic route diagram for vinylporphyrin imine compounds.

[0040] Figure 2 The image shows the 1H NMR spectrum of vinylporphyrin imine compound 1.

[0041] Figure 3 The infrared spectrum of the silanized porphyrin trifluoromethyl functional polymer. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] Unless otherwise specified, the experimental methods used in the embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0044] High-purity spherical zinc oxide coated with silica: self-made, preparation method as follows:

[0045] 100g of high-purity spherical zinc oxide slurry was sonicated for 30min, and then ammonia was added dropwise under stirring to adjust the pH to 8. The system was then heated to 65℃. 5g of tetraethyl silicate was mixed with 14mL of anhydrous ethanol to prepare an ethanol solution of tetraethyl silicate with a molar ratio of 1:10 and a concentration of 1.4mol / L. This solution was placed in a constant pressure dropping funnel and added dropwise at 1 drop / second with stirring at 700rpm to the above high-purity spherical zinc oxide system. The dropping time was controlled within 2h. 0.1-0.3mol / L ammonia was added to maintain the pH at 8-10. After the addition was complete, the reaction continued for 5h. After the reaction was completed, heating was stopped, and the mixture was aged at 200rpm for 8h at room temperature. The product was separated by centrifugation and washed three times with anhydrous ethanol and deionized water until the conductivity of the supernatant was ≤5μS / cm. The washed product was vacuum dried at 75℃ for 8h to obtain silica-coated high-purity spherical zinc oxide.

[0046] Vinylporphyrin imine compound 1: prepared in-house, as follows:

[0047] Place 1.0 eq of 5,10,15,20-tetra(4-aminophenyl)porphyrin in a Shrek flask, deoxygenate and purge with nitrogen, add 50 mL of anhydrous dichloromethane, and stir to dissolve; then add 1.1 eq of p-vinylbenzaldehyde relative to 5,10,15,20-tetra(4-aminophenyl)porphyrin dissolved in 5 mL of anhydrous dichloromethane, and place the solution in a constant pressure dropping funnel; then add 0.1 eq of p-vinylbenzaldehyde relative to 5,10,15,20-tetra(4-aminophenyl)porphyrin. 0.5 times the volume of dried p-toluenesulfonic acid was added; under nitrogen protection and in the dark, a dichloromethane solution of p-vinylbenzaldehyde was slowly added dropwise to the reaction flask, and the reaction was stirred for 4 hours. After the reaction was completed, the reaction solution was placed in an ice bath, and 40 mg of sodium bicarbonate solid was added in batches until the pH reached 7-8. The solution was then filtered, dried with anhydrous sodium sulfate, filtered again, concentrated under reduced pressure at 30 °C, and purified by neutral alumina column chromatography to obtain vinylporphyrin imine compound 1, with the structure shown below:

[0048]

[0049] Vinyltriphenylmethane imine compound 2: Prepared in-house, the preparation method differs from that of the vinylporphyrin imine compound in that 5,10,15,20-tetrakis(4-aminophenyl)porphyrin is replaced with 4,4',4"-triaminotriphenylmethane, while other conditions remain unchanged, yielding the vinyltriphenylmethane imine compound with the structure shown below:

[0050]

[0051] Vinyl compound: styrene, product number S110375, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0052] p-Vinylbenzaldehyde: Product No. N104181, purchased from Shanghai Hecheng Pharmaceutical Technology Co., Ltd.;

[0053] 5,10,15,20-Tetra(4-aminophenyl)porphyrin: purchased from Shanghai Tengqian Biotechnology Co., Ltd.;

[0054] Initiator: Azobisisobutyronitrile, product number A800353, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0055] Epoxysilane coupling agent: 3-glycidyl etheroxypropyltriethoxysilane, product number G832117, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0056] High-purity spherical zinc oxide: purity ≥99.9%, product number DXN-TS3000, average particle size 3~4μm, purchased from Darcy Nanotechnology (Changzhou) Co., Ltd.

[0057] Silica: purity ≥99%, particle size 500nm, selected from Ji'an Yushun New Materials Co., Ltd.;

[0058] Glacial acetic acid: 99.9% purity, purchased from Liaocheng Jinxinda New Materials Co., Ltd.;

[0059] Tetraethyl silicate: Product number T819505, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0060] Preparation Example

[0061] Preparation Example 1

[0062] Silanized porphyrin trifluoromethyl functional polymer 1: In-house prepared according to the following method:

[0063] Vinylporphyrinimide compound 1, 4-trifluoromethylstyrene and vinyl compound were weighed in a molar ratio of 1:4:8. First, vinylporphyrinimide compound, 4-trifluoromethylstyrene and an initiator with a molar amount of 0.015 times that of vinylporphyrinimide compound were dissolved in toluene. The solution was then placed in an ice bath and circulated under vacuum and nitrogen three times. Afterwards, free radical polymerization was carried out at 70°C under a nitrogen atmosphere for 4 hours. Then, the vinyl compound and an initiator with a molar amount of 0.005 times that of vinylporphyrinimide compound were added, and the reaction was continued for another 5 hours. After the reaction mixture was cooled to room temperature, it was added dropwise to a mixture of cold n-hexane and methanol equivalent to 10 times the volume of the reaction liquid to precipitate. After centrifugation, the solid was dissolved in dichloromethane at a ratio of 1 g of solid to 10 mL of dichloromethane, added dropwise to 10 times the volume of cold n-hexane to precipitate, centrifuged, and the solid was placed in a container... The porphyrin functional polymer was prepared by vacuum drying at 40℃ for 12 h to constant weight. The functional polymer was dissolved in anhydrous toluene in a Shrek flask and circulated under vacuum and nitrogen three times. Freshly distilled epoxy silane coupling agent, three times the molar amount relative to the porphyrin amino group, was slowly injected under nitrogen atmosphere with stirring. The reaction was carried out at 25℃ in the dark for 24 h with stirring. The reaction solution was concentrated under reduced pressure to one-fifth of the original volume. The concentrate was slowly added dropwise to cold n-hexane with vigorous stirring to precipitate the solid. The solid was centrifuged, dissolved in dichloromethane, and added dropwise to cold n-hexane again. The solid was centrifuged, and the precipitate was collected. This process was repeated three times. Finally, the precipitate was vacuum dried at 40℃ for 24 h to obtain silanized porphyrin trifluoromethyl functional polymer 1. The number average molecular weight Mn = 8500 Da, the weight average molecular weight Mw = 11220 Da, and the PDI = 1.32 were obtained by gel permeation chromatography.

[0064] Preparation Example 2

[0065] Silanized porphyrin trifluoromethyl functional polymer 2: prepared in-house. The preparation method is the same as that of silanized porphyrin trifluoromethyl functional polymer 1, except that vinylporphyrin imine compound 1, 4-trifluoromethylstyrene and vinyl compound are weighed in a molar ratio of 1:2:6, while other conditions remain unchanged. Silanized porphyrin trifluoromethyl functional polymer 2 was obtained. Gel permeation chromatography showed that the number average molecular weight Mn = 8300 Da, the weight average molecular weight Mw = 10500 Da, and the PDI = 1.26.

[0066] Preparation Example 3

[0067] Silanized porphyrin trifluoromethyl functional polymer 3: prepared in-house. The preparation method is the same as that of silanized porphyrin trifluoromethyl functional polymer 1, except that vinylporphyrin imine compound 1, 4-trifluoromethylstyrene and vinyl compound are weighed in a molar ratio of 1:5:10, while other conditions remain unchanged. Silanized porphyrin trifluoromethyl functional polymer 3 was obtained. Gel permeation chromatography showed that the number average molecular weight Mn = 8700 Da, the weight average molecular weight Mw = 11500 Da, and the PDI = 1.32.

[0068] Preparation Example 4

[0069] Silanized triphenylmethane trifluoromethyl functional polymer 4: prepared in-house. The preparation method is the same as that of silanized porphyrin trifluoromethyl functional polymer 1, except that vinylporphyrin imine compound 1 is replaced with vinyltriphenylmethane imine compound 2, while other conditions remain unchanged, thus obtaining silanized triphenylmethane trifluoromethyl functional polymer 4.

[0070] Preparation Example 5

[0071] Silanized porphyrin functional polymer 5: prepared in-house. The preparation method is the same as that of silanized porphyrin trifluoromethyl functional polymer 1, except that 4-trifluoromethylstyrene is replaced with 4-methylstyrene, while other conditions remain unchanged, thus obtaining silanized porphyrin functional polymer 5.

[0072] Preparation Example 6

[0073] Porphyrin trifluoromethyl functional polymer 6: prepared in-house. The preparation method is the same as that of silanized porphyrin trifluoromethyl functional polymer 1, except that no epoxy silane coupling agent is added, while other conditions remain unchanged, to obtain porphyrin trifluoromethyl functional polymer 6.

[0074] The raw materials and equipment used in the embodiments and comparative examples are described below:

[0075] Example

[0076] Examples 1-5 and Comparative Examples 1-3

[0077] High-purity spherical zinc oxide-silica synergistic photocatalytic air purification materials 1-8: self-made, preparation method as follows:

[0078] S1. Add 100 parts of high-purity spherical zinc oxide coated with silica to a mixed solution of 2000-2500 parts of ethanol and 100-200 parts of water, and sonicate for 30 minutes to form a uniform suspension.

[0079] S2. Adjust the pH of the suspension to 6-7 with a mixture of 0.006-0.06 parts glacial acetic acid and 1-3 parts deionized water, heat to 65°C, and stir at 700 rpm.

[0080] S3. Dissolve one of the following functional polymers: 1-3 parts of silanized porphyrin trifluoromethyl functional polymer 1-3, silanized triphenylmethane trifluoromethyl functional polymer 4, silanized porphyrin functional polymer 5, and porphyrin trifluoromethyl functional polymer 6 in 400-450 parts of ethanol, add 0.5-1 parts of deionized water, stir evenly, pre-hydrolyze at room temperature for 25 min, then sonicate for 15 min to ensure dispersion, put into a constant pressure dropping funnel, and add it to the system described in S2 at a rate of 1 drop / second, while maintaining the rotation speed at 700 rpm;

[0081] S4. After the addition is complete, continue stirring at 65°C for 6 hours, and then age at room temperature at 70 rpm for 10 hours.

[0082] S5. Centrifuge the product and wash it three times alternately with anhydrous ethanol and deionized water until the conductivity of the supernatant is ≤5μS / cm; dry the washed product under vacuum at 75℃ for 10h to obtain high-purity spherical zinc oxide-silica synergistic photocatalytic air purification materials 1-8.

[0083] Table 1. Raw material formulations (by weight) for Examples 1-5 and Comparative Examples 1-3.

[0084]

[0085] The following are the test methods for performance parameters involved in this invention:

[0086] 1. Nuclear magnetic resonance hydrogen spectrum test: The silanized porphyrin trifluoromethyl functional polymer 1 was characterized by nuclear magnetic resonance spectroscopy instrument (Bruker AM-600, Advance600); where δ=-2.7ppm is the characteristic peak of NH proton in the porphyrin ring.

[0087] 2. Fourier transform infrared spectroscopy (FT-IR): FT-IR analysis was performed using a Thermo Nicolet IS10 Fourier transform infrared spectrometer.

[0088] 3. Formaldehyde and toluene removal effectiveness test:

[0089] (1) At 0.5m 3 Formaldehyde and toluene were introduced into a square, sealed glass test chamber to initially set the formaldehyde concentration at 20 mg / m³. 3 Toluene content is 30 mg / m³ 3；

[0090] (2) The spraying of Examples 1 to 5 and Comparative Examples 1 to 3 was carried out in batches in the sealed glass. Each test was sprayed 4 times, and each time the pressure was pressed for 3 seconds. The total amount was 2 mL. The light source of the light group was natural light from 10 am to 3 pm on a sunny day. The dark group was tested in a dark room. The formaldehyde and toluene content in the sealed glass box were tested respectively. The average value of the three results was taken. The test results are shown in Table 2.

[0091] Table 2 Performance test results of Examples 1-5 and Comparative Examples 1-3

[0092]

[0093] As shown in Table 2, compared with Comparative Example 1, the content of formaldehyde and toluene in Examples 1-3 decreased significantly after 5 hours of irradiation. This is presumably due to the porphyrin ring in the silanized porphyrin trifluoromethyl functional polymer reducing the concentration of pollutants. Compared with Comparative Example 2, the content of formaldehyde in Examples 1-3 was even lower after 5 hours of irradiation. This is presumably because the introduction of trifluoromethyl groups helps to increase the reaction probability and accelerate degradation. Compared with Comparative Example 3, the performance of Comparative Example 3 decreased. This is presumably because uncrosslinked polymers are prone to detachment from the silica surface, while silanization allows the polymer to be linked to silica through chemical bonds, ensuring its interfacial stability.

[0094] Compared to Example 2, Example 3 has a higher proportion of trifluoromethyl and porphyrin units and lower levels of formaldehyde and toluene residues. It is speculated that increasing the trifluoromethyl unit can accelerate degradation, while increasing the porphyrin unit can improve visible light capture. The two work synergistically to optimize photocatalytic efficiency.

[0095] To further verify the photocatalytic effect of the material, a comparative experiment was conducted in a dark environment. The material of the present invention was exposed to pollutants for the same amount of time in the dark. The results showed that the pollutant removal rate decreased much less than under light conditions, and no corresponding degradation products were detected. This indicates that physical adsorption mainly occurs in the dark environment, and the amount of adsorption is limited. This further proves that the removal of pollutants by the material of the present invention mainly relies on photocatalytic degradation.

[0096] In summary, the silanized porphyrin trifluoromethyl functional polymer of the present invention improves the air purification performance of the present invention through multi-dimensional synergy of porphyrin visible light capture, trifluoromethyl accelerated degradation, zinc oxide photocatalytic degradation, and silanization interface stabilization.

[0097] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material, characterized in that, By weight, the product comprises 100 parts of high-purity spherical zinc oxide coated with silica and 1-3 parts of a silanized porphyrin trifluoromethyl functional polymer; the structure of the silanized porphyrin trifluoromethyl functional polymer is shown in Formula 1. Equation 1; where R is , One or two of them, a:b:c = (6~10):(2~5):

1.

2. The high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material as described in claim 1, characterized in that, The method for preparing the silica-coated high-purity spherical zinc oxide includes the following steps: The high-purity spherical zinc oxide slurry was sonicated, and then ammonia was added dropwise under stirring to adjust the pH to 8-10. The system was then heated to 60-70°C. An ethanol solution of tetraethyl silicate was added dropwise to the high-purity spherical zinc oxide system, and the reaction was allowed to proceed for 4-6 hours. After the reaction was completed, heating was stopped, and the mixture was aged for 6-12 hours. After purification and drying, high-purity spherical zinc oxide coated with silica was obtained.

3. The high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material as described in claim 2, characterized in that, The high-purity spherical zinc oxide slurry contains 20%~30% spherical zinc oxide by mass; the solvent of the slurry is a mixture of ethanol and water; the amount of tetraethyl silicate added is 2%~5% relative to the mass of the high-purity spherical zinc oxide; the molar ratio of tetraethyl silicate to ethanol in the tetraethyl silicate ethanol solution is 1:(8~15); the concentration of the tetraethyl silicate ethanol solution is 1.1~2.1 mol / L; when the tetraethyl silicate ethanol solution is added dropwise to the above high-purity spherical zinc oxide system, 0.1~0.3 mol / L ammonia water needs to be added to maintain the pH at 8~10.

4. The high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material as described in claim 1, characterized in that, The preparation method of the silanized porphyrin trifluoromethyl functional polymer includes the following steps: Vinylporphyrinimide compound, 4-trifluoromethylstyrene, and vinyl compound were weighed in a molar ratio of 1:(2~5):(6~10). First, the vinylporphyrinimide compound, 4-trifluoromethylstyrene, and an initiator of 0.01~0.015 times the molar amount of the vinylporphyrinimide compound were dissolved in toluene. The solution was then placed in an ice bath and evacuated under nitrogen for three cycles. Free radical polymerization was carried out at 65~75℃ under a nitrogen atmosphere for 3~4 h. Then, the vinyl compound and an initiator of 0.004~0.006 times the molar amount of the vinylporphyrinimide compound were added, and the reaction was continued for another 4~5 h. After cooling the reaction mixture to room temperature, it was centrifuged, precipitated, and vacuum dried to constant weight to obtain the porphyrin functional polymer. The porphyrin functional polymer was dissolved in anhydrous toluene, and freshly distilled epoxysilane coupling agent was slowly injected while stirring under a nitrogen atmosphere. The reaction was carried out at 25~30℃ in the dark for 24~48 hours. h; after vacuum concentration, centrifugation, and precipitation, silanized porphyrin trifluoromethyl functional polymer was obtained.

5. The high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material as described in claim 4, characterized in that, The vinyl compound is selected from 4-methylstyrene and styrene, or two of them; the initiator is selected from azobisisobutyronitrile; the epoxy silane coupling agent is selected from 3-glycidyl etheroxypropyltriethoxysilane and 3-glycidyl etheroxypropyltrimethoxysilane, or two of them; the amount of epoxy silane coupling agent added is 3 to 5 times relative to the molar amount of porphyrin amino.

6. The high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material as described in claim 4, characterized in that, The method for preparing the vinylporphyrin imine compound includes the following steps: Under a nitrogen atmosphere, 5,10,15,20-tetra(4-aminophenyl)porphyrin was dissolved in anhydrous dichloromethane, followed by the addition of dried p-toluenesulfonic acid. A dichloromethane solution of p-vinylbenzaldehyde was slowly added dropwise to the reaction flask under nitrogen protection and in the dark, and the reaction was continued with stirring for 3–5 h. After the reaction was complete, the reaction solution was placed in an ice bath, the pH was adjusted to 7–8, and the solution was filtered. The filtrate was dried over anhydrous sodium sulfate and then filtered again. The solution was concentrated under reduced pressure and purified by neutral alumina column chromatography to obtain the vinylporphyrin imine compound.

7. The high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material as described in claim 6, characterized in that, The amount of dried p-toluenesulfonic acid added is 0.02 to 0.05 times the molar amount of 5,10,15,20-tetra(4-aminophenyl)porphyrin; the amount of p-vinylbenzaldehyde added is 1.05 to 1.25 times the molar amount of 5,10,15,20-tetra(4-aminophenyl)porphyrin; the p-vinylbenzaldehyde needs to be purified by vacuum distillation before use, and 0.1% hydroquinone is added to inhibit polymerization.

8. The preparation method of the high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material as described in any one of claims 1 to 7, characterized in that, By weight, the following steps are included: S1. Add 100 parts of high-purity spherical zinc oxide coated with silica to a mixed solution of 2000-3000 parts of ethanol and 100-200 parts of water, and sonicate to form a uniform suspension; S2. Adjust the pH of the suspension to 6-7 with a mixture of 0.006-0.06 parts glacial acetic acid and 1-3 parts deionized water, and heat to 60-70℃ while stirring; S3. Dissolve 1-3 parts of silanized porphyrin trifluoromethyl functional polymer in 400-450 parts of ethanol, add 0.5-1 parts of deionized water, stir evenly, pre-hydrolyze at room temperature and ensure dispersion, and dropwise add to the S2 system while maintaining a rotation speed of 600-800 rpm; S4. After the addition is complete, continue stirring the reaction at 60~70℃, and then age and stir at room temperature; S5. The product is separated by centrifugation, washed, and vacuum dried to obtain a high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material.

9. The preparation method of the high-purity spherical zinc oxide-silica synergistic photocatalytic air purification material as described in claim 8, characterized in that, The dropping rate of the silanized porphyrin trifluoromethyl functional polymer in step S3 is 1~3 drops / second; the stirring speed of the aging process in step S4 is 50~80 rpm.

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