Graphene modified photocatalyst material, preparation method thereof and application thereof in air purification in tropical island climate environment

Abstract

The application provides a graphene modified photocatalyst material and a preparation method thereof and application of the graphene modified photocatalyst material in air purification in a tropical island climate environment, and belongs to the technical field of graphene modified photocatalyst materials. Zeolite is treated with phosphoric acid, then is immersed in iron / graphene doped titanium sol, and is calcined to obtain iron / graphene doped TiO2 loaded zeolite, a layer of Ag is deposited on the surface of the iron / graphene doped TiO2 loaded zeolite, and amino acid is fixed by immersion to obtain the graphene modified photocatalyst material. The graphene modified photocatalyst material has good adsorption effect on various harmful gases, meanwhile, nano metal oxides have a persistent catalytic decomposition effect on organic volatile substances, and nano metal silver has a good killing and bacteriostatic effect on bacteria and viruses in air, so that the graphene modified photocatalyst material has the effects of efficient sterilization and bacteriostasis, air purification and degradation of harmful organic substances, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of graphene-modified photocatalyst materials, specifically to a graphene-modified photocatalyst material and its preparation method, as well as its application in air purification in tropical island climates. Background Technology

[0002] Air purification materials refer to products that utilize the adsorption and decomposition principles inherent in natural substances, and are processed using modern scientific and technological methods to eliminate harmful gases and remove various odors from the air.

[0003] There are many air purification materials on the market, some good and some bad. Generally speaking, they can be categorized into the following types: First, adsorption-type air purifiers, such as activated carbon and bamboo charcoal. For example, Chinese patent CN103752257A discloses an air purifier for adsorbing formaldehyde and its preparation method. The main adsorption active component of this air purifier is a copper-aluminum composite oxide with a copper aluminate crystal phase. This adsorption active component also includes metal elements, specifically one or a mixture of manganese, cobalt, zinc, nickel, and iron. This invention uses a copper-aluminum composite oxide with a copper aluminate crystal phase as the active adsorbent for formaldehyde. This oxide has a well-developed pore structure, a large specific surface area, and good thermal stability. Furthermore, its pore structure is more suitable than that of alumina for adsorbing formaldehyde, resulting in good adsorption performance for small formaldehyde molecules. The copper atoms in the oxide, with their strong electron-withdrawing ability, can combine with the carbonyl groups of formaldehyde, further enhancing the adsorption effect. Second, there are masking odor-removing products, such as deodorizing boxes and air fresheners. For example, Chinese patent CN103239745A discloses a composite air purifier, its preparation method, and its uses. This purifier is composed of multiple components, including thyme essential oil, tea tree essential oil, chestnut flower extract, peony root bark extract, vine tea extract, gardenia essential oil, osmanthus essential oil, costus root oil, lily of the valley alcohol, nerol, citric acid, allyl 2-isopentoxyacetate, ethanol, additives, 4-hydroxy-3-butylphthalide, and deionized water. Due to the appropriate selection of components and proportions, as well as the synergistic effect between components, this air purifier exhibits excellent bactericidal, mosquito-repellent, and fragrance-enhancing properties. It also has advantages such as low dosage and long-lasting effect, making it more economical and convenient for people's lives and use. Third, decomposition-type odor removal products, such as Chinese Patent Publication No. CN1788796A, which discloses a nano-photocatalytic bactericidal air purifier. The air purifier is prepared from the following raw materials in the following weight ratio: nano-grade titanium dioxide 0.1-5, nano-grade silicon dioxide 2-10, bactericide 0.1-0.3, propylene glycol 2-5, sodium hexametaphosphate 0.3-1, surfactant 0.5-5, polydimethylsiloxane 0.5-1, organosilicon leveling agent 0.1-1, rare earth activator 0.3-1.2, and deionized water 70-100. The above raw materials are mixed evenly in the above proportions and then emulsified and dispersed to prepare the nano-photocatalytic bactericidal air purifier.

[0004] Adsorption-type air purifiers are purification products that remove pollutants using the physical adsorption, chemical adsorption, oxidation, catalytic oxidation, and reduction properties of activated carbon. The raw materials for activated carbon are mainly carbon-containing materials such as coal and wood, which are relatively expensive. Sludge contains a large amount of organic matter, providing the objective conditions for processing into carbon-containing adsorbents. Activated carbon is prepared using the pyrolysis method of sludge, which not only yields inexpensive activated carbon but also converts soluble heavy metals in sludge into insoluble substances and fixes them within the activated carbon, thereby reducing environmental pollution. Furthermore, sludge-based activated carbon can be applied to wastewater treatment, air conditioning purification, decolorization, and the treatment of toxic and harmful substances. Activated carbon is a porous carbonaceous material with a highly developed pore structure that gives it a large surface area, allowing it to easily come into full contact with toxic and harmful gases in the air. This highly developed pore structure forms a strong adsorption field, endowing activated carbon with unique adsorption properties, thus achieving adsorption and purification. Currently, the market mainly offers chemical, biological, and photocatalyst products. These products are expensive and have certain limitations in their application. Activated carbon, on the other hand, is widely used due to its affordability, ease of use, lack of pollution and side effects, and ideal performance. However, ordinary activated carbon has disadvantages such as low specific surface area, poor adsorption performance, easy saturation of the adsorbent, low adsorption efficiency, and inconvenient separation.

[0005] Air pollutants mainly include volatile organic compounds such as formaldehyde, toluene, and xylene, with formaldehyde posing the greatest threat to human health. Nanoscale titanium dioxide (TiO2), as a highly attractive photocatalyst, has garnered widespread attention in high-tech fields such as self-cleaning, sensors, photoelectric conversion, antimicrobial agents, materials science, deodorization, and pollutant degradation, primarily due to its excellent performance, chemical stability, non-toxicity, and low production cost. However, the main limitation to its application is its relatively wide band gap (3.2 eV for anatase), which restricts its excitation to UV and lacks response to visible light. Therefore, extending the absorption wavelength of nano-TiO2 into the visible light region and improving its catalytic efficiency and photocatalytic activity has become a current research hotspot. Ion doping of TiO2 can reduce its band gap and electron-hole recombination, improving catalytic efficiency, while co-doping modification can leverage the synergistic advantages of various ions, further enhancing its photocatalytic efficiency, expanding the absorption spectrum, and improving its catalytic activity under visible light. Summary of the Invention

[0006] The purpose of this invention is to propose a graphene-modified photocatalyst material and its preparation method, as well as its application in air purification in tropical island climates. It has excellent adsorption effects on various harmful gases such as CO, CO2, H2S, ammonia, HCHO, CH3NH2, and CH3CN. At the same time, the nano-metal oxides have a sustained catalytic decomposition effect on volatile organic compounds, and the nano-silver has a good bactericidal and bacteriostatic effect on bacteria and viruses in the air. Thus, it has the effects of highly efficient bactericidal and bacteriostatic action, air purification, and degradation of harmful organic matter, and has broad application prospects.

[0007] The technical solution of this invention is implemented as follows: This invention provides a method for preparing graphene-modified photocatalyst materials. Zeolite is treated with phosphoric acid, impregnated in iron / graphene-doped titanium sol, and calcined to obtain iron / graphene-doped TiO2-supported zeolite. An Ag layer is deposited on the surface, and amino acids are fixed by impregnation to obtain graphene-modified photocatalyst materials.

[0008] As a further improvement to the present invention, the following steps are included: S1. Pretreatment of zeolite: Zeolite powder is obtained by ball milling, added to phosphoric acid solution, soaked, filtered, washed and dried to obtain pretreated zeolite. S2. Preparation of dopant solution: Disperse soluble iron salt and graphene oxide in water to obtain dopant solution; S3. Preparation of modified titanium sol: Tetrabutyl titanate was dissolved in ethanol, diethanolamine was added, the mixture was stirred and mixed evenly, nitric acid and dopant were added dropwise, and the mixture was stirred to form modified titanium sol; S4. Preparation of iron / graphene-doped TiO2-supported zeolite: The pretreated zeolite was added to the modified titanium sol, impregnated, removed, dried, and calcined under an inert gas atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Preparation of silver ammonia complex ion solution: Dissolve soluble silver salt in water, add ammonia dropwise until the precipitate just disappears, and obtain silver ammonia complex ion solution; S6. Silver deposition: Iron / graphene-doped TiO2-supported zeolite was added to water, glucose was added, and the mixture was stirred and mixed evenly. Silver ammonia complex ion solution was added dropwise, and the mixture was heated and stirred to react. The mixture was filtered, washed, and dried to obtain Ag-deposited iron / graphene-doped TiO2-supported zeolite. S7. Amino acid fixation: The composite amino acid was dissolved in water, and Ag-deposited iron / graphene-doped TiO2-supported zeolite was added. The mixture was stirred and mixed evenly, and the solvent was allowed to evaporate naturally to obtain the graphene-modified photocatalyst material.

[0009] As a further improvement of the present invention, the zeolite in step S1 is 4A zeolite, the ball milling time is 1-2 hours, and the mass ratio of the zeolite powder to the phosphoric acid solution is 10-12:25-30.

[0010] As a further improvement of the present invention, the soluble iron salt in step S2 is selected from at least one of ferric nitrate, ferric chloride, and ferric sulfate, and the mass ratio of the soluble iron salt, graphene oxide, and water is 7-10:0.2-0.3:20-30; the mass ratio of tetrabutyl titanate, ethanol, diethanolamine, nitric acid, and dopant solution in step S3 is 15-20:70-100:3-5:1-3:5-7, the concentration of the nitric acid is 40-55 wt%, and the stirring time is 3-5 h.

[0011] As a further improvement of the present invention, in step S4, the mass ratio of the pretreated zeolite to the modified titanium sol is 10-20:15-27, and the calcination temperature is 480-520℃ for 1-3 hours.

[0012] As a further improvement of the present invention, the soluble silver salt in step S5 is silver nitrate, the concentration of the soluble silver salt solution is 0.5-1 mol / L, and the concentration of the ammonia water is 10-15 wt%.

[0013] As a further improvement of the present invention, the mass ratio of the iron / graphene-doped TiO2-supported zeolite, glucose, and silver ammonia complex solution in step S6 is 15-20:3-5:7-10, and the heating and stirring reaction temperature is 80-90℃, and the time is 0.5-1h.

[0014] As a further improvement of the present invention, the composite amino acid in step S7 is lysine and sodium glycine in a mass ratio of 7-10:2-3, and the mass ratio of the composite amino acid to the Ag-deposited iron / graphene-doped TiO2-supported zeolite is 3-5:50-60.

[0015] This invention further protects the application of the above-mentioned graphene-modified photocatalyst material in air purification in tropical island climate environments.

[0016] This invention further protects a graphene-modified photocatalyst material prepared by the above-described preparation method.

[0017] The present invention has the following beneficial effects: 4A zeolite is a sodium-type zeolite with a crystal lattice framework containing many cavities, which can adsorb harmful gases such as CO, CO2, H2S, HCHO, CH3NH2, and CH3CN. It is an excellent solid adsorbent. After phosphoric acid treatment, the adsorption effect of zeolite on H2S and ammonia is further improved. At the same time, a large number of hydroxyl structures are generated on the zeolite surface, which improves the effect of its fixation with the subsequent titanium sol through hydrogen bonds, and greatly increases the loading capacity of the modified titanium sol.

[0018] Iron ions were added to the doping solution, and graphene oxide was added to the preparation of the modified titanium sol. This allowed the iron ions and graphene oxide deposited on the TiO2-loaded zeolite to be reduced to obtain graphene. Iron ion doping caused a red shift in the absorption threshold wavelength, significantly narrowing the band gap of TiO2, enabling it to absorb longer wavelength photons and increasing the photocatalytic ability of the nano-TiO2 photocatalyst in the visible light region. Graphene gave the TiO2 surface a carbon layer, which not only reduced the number of hydroxyl groups on the nano-TiO2 surface to prevent its aggregation, but also acted as a photosensitizer. In synergy with iron ions, the carbon layer transferred visible light energy to TiO2, enhancing the visible light photocatalytic efficiency of TiO2.

[0019] TiO2 exhibits high activity, good stability, non-toxicity to humans, and excellent antibacterial effects. This invention utilizes a sol-gel method to prepare titanium sol, where diethanolamine acts as an inhibitor and nitric acid serves as a catalyst, resulting in a uniform and transparent sol. This sol is then calcined at 480-520℃ to obtain anatase TiO2, which possesses good photocatalytic activity. Furthermore, the loading of iron ions and graphene enhances the photocatalytic activity of the prepared TiO2 in the visible light region.

[0020] Taking advantage of the limitations of ultraviolet light energy, nano-TiO2 materials are synthesized by incorporating trace amounts of metals and non-metals. This allows for photodegradation and bactericidal / bacteriostatic functions under ultraviolet light, general visible light, or low light conditions. Among metals, Cu, Ag, Au, and zinc all possess antibacterial properties. Due to the broad-spectrum antibacterial activity, high bactericidal efficiency, and low likelihood of drug resistance, silver ions have recently shown superior bactericidal effects when used as inorganic antibacterial agents, particularly silver-doped nano-TiO2. In this invention, silver acts as a co-catalyst; the Fermi level difference causes photogenerated electrons in TiO2 to migrate towards the silver particles, achieving effective electron-hole separation and enhancing both photocatalytic and antibacterial effects.

[0021] This invention utilizes nano-Ag, deposited on a surface. Upon contact with bacteria, molds, viruses, etc., it can penetrate the cell wall, disrupt the activity of cellular synthetic enzymes, and react with the sulfhydryl groups of bacteria, coagulating bacterial proteins and further interfering with and damaging their physiological systems, causing the cells to lose their ability to divide and reproduce, leading to cell death. Simultaneously, because the nano-silver is successfully doped into the lattice defects of TiO2, it creates a low-bandgap energy electric field, generating highly oxidizing OH-(OH·) free radicals and reactive peroxide ions at very low external energy, rapidly causing the death of bacteria, molds, and viruses. Once the bacteria lose their activity, the Ag... + It will then be released from the bacteria and repeat the bactericidal activity. This allows the bactericidal function of the silver-loaded graphene-modified photocatalyst material of this invention to be effective for a long time without consuming the material itself. It has good bactericidal effect, long-lasting antibacterial properties, and wide applications. It has antibacterial, antifungal, bactericidal, and purifying functions. It has a high inhibition rate against fungi, Escherichia coli, Staphylococcus aureus, hepatitis B virus, foot-and-mouth disease, anthrax, and other bacteria and viruses, and has no toxic side effects.

[0022] This invention further involves impregnating and immobilizing amino acids on the surface of Ag-deposited iron / graphene-doped TiO2-supported zeolite. The small amino acid molecules can rapidly polymerize with organic compounds such as formaldehyde to immobilize harmful molecules. Furthermore, the nano-metal oxides exert a sustained catalytic decomposition effect on volatile organic compounds, thereby achieving efficient degradation and purification.

[0023] The graphene-modified photocatalyst material prepared by this invention has excellent adsorption effects on various harmful gases such as CO, CO2, H2S, ammonia, HCHO, CH3NH2, and CH3CN. At the same time, the nano-metal oxides have a sustained catalytic decomposition effect on volatile organic compounds, and the nano-silver has a good bactericidal and bacteriostatic effect on bacteria and viruses in the air. Thus, it has the effects of highly efficient bactericidal and bacteriostatic action, air purification, and degradation of harmful organic matter, and has broad application prospects. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The image shows the XRD pattern of the graphene-modified photocatalyst material prepared in Example 1 of this invention.

[0026] Figure 2 The infrared spectrum of the graphene-modified photocatalyst material prepared in Example 1 of this invention is shown.

[0027] Figure 3 This is a SEM image of the graphene-modified photocatalyst material prepared according to an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] 4A zeolite, 3-5 mm, purity >99%; graphene oxide, particle size 0.1-1.0 µm, purity >97%, 3-5 layers; nitric acid, concentration 40%; ammonia, concentration 25 wt%.

[0030] Example 1

[0031] This embodiment provides a method for preparing a graphene-modified photocatalyst material, specifically including the following steps: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1 hour to obtain zeolite powder. 10 parts by weight of zeolite powder were added to 25 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of dopant solution: 7 parts by weight of ferric chloride and 0.2 parts by weight of graphene oxide are dispersed in 20 parts by weight of water to obtain dopant solution; S3. Preparation of modified titanium sol: 15 parts by weight of tetrabutyl titanate were dissolved in 70 parts by weight of ethanol, 3 parts by weight of diethanolamine were added, and the mixture was stirred for 30 min. 1 part by weight of 40 wt% nitric acid and 5 parts by weight of dopant solution were added dropwise, and the mixture was stirred for 3 h to form modified titanium sol. S4. Preparation of iron / graphene-doped TiO2-supported zeolite: 10 parts by weight of pretreated zeolite were added to 15 parts by weight of modified titanium sol, immersed for 30 seconds, removed, and the immersion was repeated twice. The zeolite was then removed, dried, and calcined at 480℃ for 1 hour under a nitrogen atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Preparation of silver ammonia complex ion solution: Add 10wt% ammonia water dropwise to 0.5mol / L silver nitrate solution until the precipitate just disappears to obtain silver ammonia complex ion solution; S6. Silver deposition: 15 parts by weight of iron / graphene-doped TiO2-supported zeolite were added to 100 parts by weight of water, 3 parts by weight of glucose were added, the mixture was stirred for 20 min, 7 parts by weight of silver ammonia complex ion solution were added dropwise, the mixture was heated to 80℃, stirred for 0.5 h, filtered, washed, and dried to obtain Ag-deposited iron / graphene-doped TiO2-supported zeolite. S7. Amino acid fixation: 3 parts by weight of composite amino acids were dissolved in 100 parts by weight of water, and 50 parts by weight of Ag-deposited iron / graphene-doped TiO2-supported zeolite were added. The mixture was stirred and mixed for 10 minutes, and the solvent was allowed to evaporate naturally to obtain graphene-modified photocatalyst material. Figure 1-3 The characterization spectrum of the obtained graphene-modified photocatalyst material is shown.

[0032] The composite amino acid is lysine and sodium glycine in a mass ratio of 7:2.

[0033] Example 2

[0034] This embodiment provides a method for preparing a graphene-modified photocatalyst material, specifically including the following steps: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 2 hours to obtain zeolite powder. 12 parts by weight of zeolite powder were added to 30 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of dopant solution: 10 parts by weight of ferric sulfate and 0.3 parts by weight of graphene oxide are dispersed in 30 parts by weight of water to obtain dopant solution; S3. Preparation of modified titanium sol: 20 parts by weight of tetrabutyl titanate were dissolved in 100 parts by weight of ethanol, 5 parts by weight of diethanolamine were added, and the mixture was stirred for 30 min. Then, 3 parts by weight of 55 wt% nitric acid and 7 parts by weight of dopant solution were added dropwise, and the mixture was stirred for 5 h to form modified titanium sol. S4. Preparation of iron / graphene-doped TiO2-supported zeolite: 20 parts by weight of pretreated zeolite were added to 27 parts by weight of modified titanium sol, immersed for 30 min, removed, dried, and calcined at 520℃ for 3 h under nitrogen atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Preparation of silver ammonia complex ion solution: Add 15wt% ammonia water dropwise to 1mol / L silver nitrate solution until the precipitate just disappears to obtain silver ammonia complex ion solution; S6. Silver deposition: 20 parts by weight of iron / graphene-doped TiO2-supported zeolite were added to 100 parts by weight of water, 5 parts by weight of glucose were added, the mixture was stirred for 20 min, 10 parts by weight of silver ammonia complex ion solution were added dropwise, the mixture was heated to 90℃, stirred for 1 h, filtered, washed, and dried to obtain Ag-deposited iron / graphene-doped TiO2-supported zeolite. S7. Amino acid fixation: 5 parts by weight of composite amino acids were dissolved in 100 parts by weight of water, and 60 parts by weight of Ag-deposited iron / graphene-doped TiO2-supported zeolite were added. The mixture was stirred and mixed for 10 minutes, and the solvent was allowed to evaporate naturally to obtain graphene-modified photocatalyst material. The composite amino acid is lysine and sodium glycine in a mass ratio of 10:3.

[0035] Example 3

[0036] This embodiment provides a method for preparing a graphene-modified photocatalyst material, specifically including the following steps: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder. 11 parts by weight of zeolite powder were added to 27 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of dopant solution: 8.5 parts by weight of ferric nitrate and 0.25 parts by weight of graphene oxide were dispersed in 25 parts by weight of water to obtain the dopant solution; S3. Preparation of modified titanium sol: 17 parts by weight of tetrabutyl titanate were dissolved in 85 parts by weight of ethanol, 4 parts by weight of diethanolamine were added, and the mixture was stirred for 30 min. Then, 2 parts by weight of 47 wt% nitric acid and 6 parts by weight of dopant solution were added dropwise, and the mixture was stirred for 4 h to form modified titanium sol. S4. Preparation of iron / graphene-doped TiO2-supported zeolite: 15 parts by weight of pretreated zeolite were added to 22 parts by weight of modified titanium sol, immersed for 30 min, removed, dried, and calcined at 500 °C for 2 h under nitrogen atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Preparation of silver ammonia complex ion solution: Add 12wt% ammonia water dropwise to 0.7mol / L silver nitrate solution until the precipitate just disappears to obtain silver ammonia complex ion solution; S6. Silver deposition: 17 parts by weight of iron / graphene-doped TiO2-supported zeolite were added to 100 parts by weight of water, 4 parts by weight of glucose were added, the mixture was stirred for 20 min, 8.5 parts by weight of silver ammonia complex ion solution were added dropwise, the mixture was heated to 85℃, stirred for 1 h, filtered, washed, and dried to obtain Ag-deposited iron / graphene-doped TiO2-supported zeolite. S7. Amino acid fixation: 4 parts by weight of composite amino acids were dissolved in 100 parts by weight of water, and 55 parts by weight of Ag-deposited iron / graphene-doped TiO2-supported zeolite were added. The mixture was stirred and mixed for 10 minutes, and the solvent was allowed to evaporate naturally to obtain graphene-modified photocatalyst material. The composite amino acid is lysine and sodium glycine in a mass ratio of 8.5:2.5.

[0037] Comparative Example 1 The difference from Example 3 is that step S1 did not involve phosphoric acid solution treatment.

[0038] Specifically as follows: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder.

[0039] Comparative Example 2 The difference from Example 3 is that no iron salt was added to the doping solution in step S2.

[0040] Specifically as follows: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder. 11 parts by weight of zeolite powder were added to 27 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of dopant solution: 0.25 parts by weight of graphene oxide were dispersed in 25 parts by weight of water to obtain the dopant solution; S3. Preparation of modified titanium sol: 17 parts by weight of tetrabutyl titanate were dissolved in 85 parts by weight of ethanol, 4 parts by weight of diethanolamine were added, and the mixture was stirred for 30 min. Then, 2 parts by weight of 47 wt% nitric acid and 6 parts by weight of dopant solution were added dropwise, and the mixture was stirred for 4 h to form modified titanium sol. S4. Preparation of graphene-doped TiO2-supported zeolite: 15 parts by weight of pretreated zeolite were added to 22 parts by weight of modified titanium sol, immersed for 30 min, removed, dried, and calcined at 500 °C for 2 h under nitrogen atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Preparation of silver ammonia complex ion solution: Add 12wt% ammonia water dropwise to 0.7mol / L silver nitrate solution until the precipitate just disappears to obtain silver ammonia complex ion solution; S6. Silver deposition: 17 parts by weight of graphene-doped TiO2-supported zeolite were added to 100 parts by weight of water, 4 parts by weight of glucose were added, the mixture was stirred for 20 min, 8.5 parts by weight of silver ammonia complex ion solution were added dropwise, the mixture was heated to 85℃, stirred for 1 h, filtered, washed, and dried to obtain Ag-deposited graphene-doped TiO2-supported zeolite. S7. Amino acid fixation: 4 parts by weight of composite amino acids were dissolved in 100 parts by weight of water, and 55 parts by weight of Ag-deposited graphene-doped TiO2-supported zeolite were added. The mixture was stirred and mixed for 10 minutes, and the solvent was allowed to evaporate naturally to obtain graphene-modified photocatalyst material. The composite amino acid is lysine and sodium glycine in a mass ratio of 8.5:2.5.

[0041] Comparative Example 3 The difference from Example 3 is that graphene oxide was not added in step S2.

[0042] Specifically as follows: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder. 11 parts by weight of zeolite powder were added to 27 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of doping solution: 8.5 parts by weight of ferric nitrate were dispersed in 25 parts by weight of water to obtain the doping solution; S3. Preparation of modified titanium sol: 17 parts by weight of tetrabutyl titanate were dissolved in 85 parts by weight of ethanol, 4 parts by weight of diethanolamine were added, and the mixture was stirred for 30 min. Then, 2 parts by weight of 47 wt% nitric acid and 6 parts by weight of dopant solution were added dropwise, and the mixture was stirred for 4 h to form modified titanium sol. S4. Preparation of iron-doped TiO2-supported zeolite: 15 parts by weight of pretreated zeolite were added to 22 parts by weight of modified titanium sol, immersed for 30 min, taken out, dried, and calcined at 500℃ for 2 h under nitrogen atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Preparation of silver ammonia complex ion solution: Add 12wt% ammonia water dropwise to 0.7mol / L silver nitrate solution until the precipitate just disappears to obtain silver ammonia complex ion solution; S6. Silver deposition: 17 parts by weight of iron-doped TiO2 supported zeolite were added to 100 parts by weight of water, 4 parts by weight of glucose were added, the mixture was stirred for 20 min, 8.5 parts by weight of silver ammonia complex ion solution were added dropwise, the mixture was heated to 85℃, stirred for 1 h, filtered, washed, and dried to obtain Ag-deposited iron-doped TiO2 supported zeolite. S7. Amino acid fixation: 4 parts by weight of composite amino acids were dissolved in 100 parts by weight of water, and 55 parts by weight of Ag-deposited iron-doped TiO2-supported zeolite were added. The mixture was stirred and mixed for 10 minutes, and the solvent was allowed to evaporate naturally to obtain graphene-modified photocatalyst material. The composite amino acid is lysine and sodium glycine in a mass ratio of 8.5:2.5.

[0043] Comparative Example 4 The difference from Example 3 is that the dopant solution in step S3 is replaced by an equal mass of water.

[0044] Specifically as follows: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder. 11 parts by weight of zeolite powder were added to 27 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of titanium sol: 17 parts by weight of tetrabutyl titanate were dissolved in 85 parts by weight of ethanol, 4 parts by weight of diethanolamine were added, and the mixture was stirred for 30 min. Then, 2 parts by weight of 47 wt% nitric acid and 6 parts by weight of water were added dropwise, and the mixture was stirred for 4 h to form titanium sol. S3. Preparation of TiO2-supported zeolite: 15 parts by weight of pretreated zeolite were added to 22 parts by weight of titanium sol, impregnated for 30 min, taken out, dried, and calcined at 500℃ for 2 h under nitrogen atmosphere to obtain TiO2-supported zeolite. S4. Preparation of silver ammonia complex ion solution: Add 12wt% ammonia water dropwise to 0.7mol / L silver nitrate solution until the precipitate just disappears to obtain silver ammonia complex ion solution; S5. Silver deposition: 17 parts by weight of TiO2-supported zeolite were added to 100 parts by weight of water, 4 parts by weight of glucose were added, the mixture was stirred for 20 min, 8.5 parts by weight of silver ammonia complex ion solution were added dropwise, the mixture was heated to 85℃, stirred for 1 h, filtered, washed, and dried to obtain Ag-deposited TiO2-supported zeolite. S6. Amino acid fixation: 4 parts by weight of composite amino acids were dissolved in 100 parts by weight of water, 55 parts by weight of Ag-deposited TiO2-supported zeolite were added, the mixture was stirred for 10 minutes, and the solvent was allowed to evaporate naturally to obtain graphene-modified photocatalyst material. The composite amino acid is lysine and sodium glycine in a mass ratio of 8.5:2.5.

[0045] Comparative Example 5 The difference from Example 3 is that steps S2 to S4 were not performed.

[0046] Specifically as follows: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder. 11 parts by weight of zeolite powder were added to 27 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of silver ammonia complex ion solution: Add 12wt% ammonia water dropwise to 0.7mol / L silver nitrate solution until the precipitate just disappears to obtain silver ammonia complex ion solution; S3. Silver deposition: 17 parts by weight of pretreated zeolite were added to 100 parts by weight of water, 4 parts by weight of glucose were added, the mixture was stirred for 20 min, 8.5 parts by weight of silver ammonia complex ion solution were added dropwise, the mixture was heated to 85°C, stirred for 1 h, filtered, washed, and dried to obtain Ag-deposited zeolite. S4. Amino acid fixation: 4 parts by weight of composite amino acids were dissolved in 100 parts by weight of water, 55 parts by weight of Ag-deposited zeolite were added, the mixture was stirred for 10 minutes, and the solvent was allowed to evaporate naturally to obtain graphene-modified photocatalyst material. The composite amino acid is lysine and sodium glycine in a mass ratio of 8.5:2.5.

[0047] Comparative Example 6 The difference from Example 3 is that steps S5 and S6 were not performed.

[0048] Specifically as follows: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder. 11 parts by weight of zeolite powder were added to 27 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of dopant solution: 8.5 parts by weight of ferric nitrate and 0.25 parts by weight of graphene oxide were dispersed in 25 parts by weight of water to obtain the dopant solution; S3. Preparation of modified titanium sol: 17 parts by weight of tetrabutyl titanate were dissolved in 85 parts by weight of ethanol, 4 parts by weight of diethanolamine were added, and the mixture was stirred for 30 min. Then, 2 parts by weight of 47 wt% nitric acid and 6 parts by weight of dopant solution were added dropwise, and the mixture was stirred for 4 h to form modified titanium sol. S4. Preparation of iron / graphene-doped TiO2-supported zeolite: 15 parts by weight of pretreated zeolite were added to 22 parts by weight of modified titanium sol, immersed for 30 min, removed, dried, and calcined at 500 °C for 2 h under nitrogen atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Amino acid fixation: 4 parts by weight of composite amino acids were dissolved in 100 parts by weight of water, and 55 parts by weight of iron / graphene-doped TiO2-supported zeolite were added. The mixture was stirred and mixed for 10 minutes, and the solvent was allowed to evaporate naturally to obtain graphene-modified photocatalyst material. The composite amino acid is lysine and sodium glycine in a mass ratio of 8.5:2.5.

[0049] Comparative Example 7 The difference from Example 3 is that step S7 was not performed.

[0050] Specifically as follows: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder. 11 parts by weight of zeolite powder were added to 27 parts by weight of 10 wt% phosphoric acid solution, soaked for 30 minutes, filtered, washed, and dried to obtain pretreated zeolite. S2. Preparation of dopant solution: 8.5 parts by weight of ferric nitrate and 0.25 parts by weight of graphene oxide were dispersed in 25 parts by weight of water to obtain the dopant solution; S3. Preparation of modified titanium sol: 17 parts by weight of tetrabutyl titanate were dissolved in 85 parts by weight of ethanol, 4 parts by weight of diethanolamine were added, and the mixture was stirred for 30 min. Then, 2 parts by weight of 47 wt% nitric acid and 6 parts by weight of dopant solution were added dropwise, and the mixture was stirred for 4 h to form modified titanium sol. S4. Preparation of iron / graphene-doped TiO2-supported zeolite: 15 parts by weight of pretreated zeolite were added to 22 parts by weight of modified titanium sol, immersed for 30 min, removed, dried, and calcined at 500 °C for 2 h under nitrogen atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Preparation of silver ammonia complex ion solution: Add 12wt% ammonia water dropwise to 0.7mol / L silver nitrate solution until the precipitate just disappears to obtain silver ammonia complex ion solution; S6. Silver deposition: 17 parts by weight of iron / graphene-doped TiO2-supported zeolite were added to 100 parts by weight of water, 4 parts by weight of glucose were added, and the mixture was stirred for 20 min. 8.5 parts by weight of silver ammonia complex ion solution were added dropwise, the mixture was heated to 85℃, stirred and reacted for 1 h, filtered, washed, and dried to obtain Ag-deposited iron / graphene-doped TiO2-supported zeolite, which is the graphene-modified photocatalyst material.

[0051] Comparative Example 8 The difference from Example 3 is that steps S2 to S7 were not performed.

[0052] Specifically as follows: S1. Pretreatment of zeolite: 4A zeolite was ball-milled for 1.5 hours to obtain zeolite powder. 11 parts by weight of zeolite powder were added to 27 parts by weight of 10 wt% phosphoric acid solution and soaked for 30 minutes. After filtration, washing and drying, pretreated zeolite was obtained, which is the graphene-modified photocatalyst material.

[0053] Test Example 1 The graphene-modified photocatalyst materials prepared in Examples 1-3 and Comparative Examples 1-8 of this invention were subjected to tests to determine their effectiveness in killing harmful microorganisms. The method for determining harmful microorganisms was in accordance with GB / T 18204.4-2013 "Hygiene Inspection Methods for Public Places Part 4: Microbiology of Public Goods and Utensils", and the tests were conducted under natural light conditions.

[0054] The results are shown in Table 1.

[0055] Table 1

[0056] As can be seen from the table above, the graphene-modified photocatalyst materials prepared in Examples 1-3 of this invention have good effects in killing harmful microorganisms.

[0057] Test Example 2 The graphene-modified photocatalyst materials prepared in Examples 1-3 and Comparative Examples 1-8 of this invention were subjected to harmful gas purification effect tests. The harmful gas determination was based on the following criteria: The determination of ammonia is based on GB / T 18204.25-2000 "Method for Determination of Ammonia in Air in Public Places"; The determination of hydrogen sulfide is based on GB / T14678-1993 "Air quality - Determination of hydrogen sulfide, methanethiol, dimethyl sulfide and dimethyl disulfide by gas chromatography". The experiment was conducted under natural light conditions, and the results are shown in Table 2.

[0058] Table 2

[0059] As can be seen from the table above, the graphene-modified photocatalyst materials prepared in Examples 1-3 of this invention have good purification effects on harmful gases.

[0060] Test Example 3 The tests were conducted according to JC / T1074-2008 "Purification Performance of Functional Coating Materials for Indoor Air Purification" and GB / T18883-2002 "Indoor Air Quality Standard". 0.2g of formaldehyde and 0.2g of toluene (analytical grade, ≥99%) were injected into the injection port of a sealed chamber containing 0.2g of graphene-modified photocatalyst material prepared in Examples 1-3 and Comparative Examples 1-8. The initial concentrations of formaldehyde and toluene in the chamber (C0, 10.0mg / m³) were tested. 3 These are the limits specified in GB / T18883-2002 (0.10 and 0.20 mg / m³). 3 The purification efficiency or natural decay rate (N) of formaldehyde and toluene in the air is 100 and 50 times that of formaldehyde and toluene, respectively, after 24 hours of observation. t =(C0-C t ) / C0×100%, where: C t Instantaneous concentration, i.e., the concentration of formaldehyde or toluene in the air at different times during the test, in mg / m³. 3 t: Test time, h.

[0061] The experiment was conducted under natural light conditions, and the results are shown in Table 3.

[0062] Table 3

[0063] As shown in the table above, the graphene-modified photocatalyst materials prepared in Examples 1-3 of this invention have good purification efficiency for formaldehyde and toluene.

[0064] Compared to Example 3, Comparative Example 1 did not involve phosphoric acid solution treatment in step S1. The ammonia removal rate and the purification efficiency for formaldehyde and toluene decreased, but the hydrogen sulfide removal rate slightly improved. 4A zeolite is a sodium-type zeolite with a crystal lattice framework containing many cavities, which can adsorb harmful gases such as CO, CO2, H2S, HCHO, CH3NH2, and CH3CN, making it an excellent solid adsorbent. Phosphoric acid treatment further improved the zeolite's adsorption effect on ammonia; however, due to the acidification process, the surface became acidic, slightly reducing the removal efficiency for other acidic H2S gases.

[0065] Compared with Example 3, Comparative Examples 2 and 3 did not add ferric nitrate or graphene oxide in step S2. Compared with Example 3, Comparative Example 4 did not add dopant in step S3. The removal rate of harmful gases, the purification efficiency of formaldehyde and toluene, and the killing efficiency of harmful microorganisms decreased. The addition of iron ions and graphene oxide to the dopant solution allows the iron ions and graphene oxide deposited on the TiO2-loaded zeolite to be reduced to graphene. Iron ion doping causes a red shift in the absorption threshold wavelength, significantly narrowing the band gap of TiO2, which can absorb longer wavelength photons, increasing the photocatalytic ability of nano-TiO2 photocatalyst material in the visible light region. Graphene gives TiO2 a carbon layer on the surface, which not only reduces the number of hydroxyl groups on the surface of nano-TiO2 to prevent its aggregation, but also allows the graphene layer on the surface of nano-TiO2 to act as an electronic conductor and charge separation aid. Utilizing its high conductivity, it receives photogenerated electrons from TiO2, inhibits electron-hole recombination, prolongs carrier lifetime, and enhances the visible light photocatalytic efficiency of TiO2 in synergy with iron ions.

[0066] Compared with Example 3, Comparative Example 5 did not perform steps S2 to S4. The removal rate of harmful gases, the purification efficiency of formaldehyde and toluene, and the killing efficiency of harmful microorganisms decreased. TiO2 has high activity, good stability, is non-toxic to humans, and has good antibacterial effects. This invention prepares titanium sol via a sol-gel method, in which diethanolamine acts as an inhibitor and nitric acid is used as a catalyst, thereby producing a uniform and transparent sol. This sol is then calcined and held at 480-520℃ to obtain anatase TiO2, which has good photocatalytic activity. After loading with iron ions and graphene, the prepared TiO2 also exhibits good photocatalytic activity in the visible light region. Simultaneously, the prepared photocatalyst also has excellent antibacterial and bacteriostatic activity.

[0067] Compared to Example 3, Comparative Example 6 omitted steps S5 and S6. The efficiency of killing harmful microorganisms decreased. In this invention, the nano-Ag element deposited on the surface, upon contact with bacteria, molds, viruses, etc., can penetrate the cell wall, disrupt the activity of cellular synthetic enzymes, and react with the hydroxyl groups of bacteria, coagulating bacterial proteins, further interfering with and damaging their physiological systems, causing the cells to lose their ability to divide and reproduce, leading to cell death. Simultaneously, because the nano-silver is successfully doped into the lattice defects of TiO2, it forms a low-bandgap energy electric field, generating highly oxidizing OH-(OH·) free radicals and reactive peroxide ions at very low external energy, rapidly leading to the death of bacteria, molds, and viruses. Once the bacteria lose their activity, the Ag... +It will then be released from the bacteria and repeat the bactericidal activity. This allows the bactericidal function of the silver-loaded graphene-modified photocatalyst material of this invention to be effective for a long time without consuming the material itself. It has good bactericidal effect, long-lasting antibacterial properties, and wide applications. It has antibacterial, antifungal, bactericidal, and purifying functions. It has a high inhibition rate against fungi, Escherichia coli, Staphylococcus aureus, hepatitis B virus, foot-and-mouth disease, anthrax, and other bacteria and viruses, and has no toxic side effects.

[0068] Compared to Example 3, Comparative Example 7 did not perform step S7. The removal rate of harmful gases and the purification efficiency of formaldehyde and toluene decreased. This invention further immobilizes amino acids by impregnating the surface of Ag-deposited iron / graphene-doped TiO2-supported zeolite. The small amino acid molecules can rapidly polymerize with organic compounds such as formaldehyde to immobilize harmful molecules. Furthermore, the nano-metal oxides provide sustained catalytic decomposition of volatile organic compounds, thereby achieving highly efficient degradation and purification.

[0069] Compared with Example 3, Comparative Example 8 did not perform steps S2 to S7, and it had almost no antibacterial effect, and the removal rate of harmful gases and the purification efficiency of formaldehyde and toluene were significantly reduced.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a graphene-modified photocatalyst material, characterized in that, Zeolite was treated with phosphoric acid, then impregnated in iron / graphene-doped titanium sol and calcined to obtain iron / graphene-doped TiO2-supported zeolite. An Ag layer was deposited on the surface, and amino acids were fixed by impregnation to obtain graphene-modified photocatalytic material.

2. The preparation method according to claim 1, characterized in that, Includes the following steps: S1. Pretreatment of zeolite: Zeolite powder is obtained by ball milling, added to phosphoric acid solution, soaked, filtered, washed and dried to obtain pretreated zeolite. S2. Preparation of dopant solution: Disperse soluble iron salt and graphene oxide in water to obtain dopant solution; S3. Preparation of modified titanium sol: Tetrabutyl titanate was dissolved in ethanol, diethanolamine was added, the mixture was stirred and mixed evenly, nitric acid and dopant were added dropwise, and the mixture was stirred to form modified titanium sol; S4. Preparation of iron / graphene-doped TiO2-supported zeolite: The pretreated zeolite was added to the modified titanium sol, impregnated, removed, dried, and calcined under an inert gas atmosphere to obtain iron / graphene-doped TiO2-supported zeolite. S5. Preparation of silver ammonia complex ion solution: Dissolve soluble silver salt in water, add ammonia dropwise until the precipitate just disappears, and obtain silver ammonia complex ion solution; S6. Silver deposition: Iron / graphene-doped TiO2-supported zeolite was added to water, glucose was added, and the mixture was stirred and mixed evenly. Silver ammonia complex ion solution was added dropwise, and the mixture was heated and stirred to react. The mixture was filtered, washed, and dried to obtain Ag-deposited iron / graphene-doped TiO2-supported zeolite. S7. Amino acid fixation: The composite amino acid was dissolved in water, and Ag-deposited iron / graphene-doped TiO2-supported zeolite was added. The mixture was stirred and mixed evenly, and the solvent was allowed to evaporate naturally to obtain the graphene-modified photocatalyst material.

3. The preparation method according to claim 2, characterized in that, The zeolite mentioned in step S1 is 4A zeolite, the ball milling time is 1-2 hours, and the mass ratio of zeolite powder to phosphoric acid solution is 10-12:25-30.

4. The preparation method according to claim 2, characterized in that, In step S2, the soluble iron salt is selected from at least one of ferric nitrate, ferric chloride, and ferric sulfate. The mass ratio of the soluble iron salt, graphene oxide, and water is 7-10:0.2-0.3:20-30. In step S3, the mass ratio of tetrabutyl titanate, ethanol, diethanolamine, nitric acid, and dopant solution is 15-20:70-100:3-5:1-3:5-7. The concentration of the nitric acid is 40-55 wt%, and the stirring time is 3-5 h.

5. The preparation method according to claim 2, characterized in that, In step S4, the mass ratio of pretreated zeolite to modified titanium sol is 10-20:15-27, and the calcination temperature is 480-520℃ for 1-3 hours.

6. The preparation method according to claim 2, characterized in that, The soluble silver salt in step S5 is silver nitrate, the concentration of the soluble silver salt solution is 0.5-1 mol / L, and the concentration of the ammonia water is 10-15 wt%.

7. The preparation method according to claim 2, characterized in that, In step S6, the mass ratio of iron / graphene-doped TiO2-supported zeolite, glucose, and silver ammonia complex solution is 15-20:3-5:7-10, and the heating and stirring reaction is carried out at a temperature of 80-90℃ for 0.5-1h.

8. The preparation method according to claim 2, characterized in that, The composite amino acid in step S7 is lysine and sodium glycine in a mass ratio of 7-10:2-3, and the mass ratio of the composite amino acid to the Ag-deposited iron / graphene-doped TiO2-supported zeolite is 3-5:50-60.

9. A graphene-modified photocatalyst material prepared by the preparation method according to any one of claims 1-8.

10. An application of the graphene-modified photocatalyst material as described in claim 9 in air purification in a tropical island climate environment.

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