Visible light photocatalytic disinfectant for pathogenic bacteria attached to aerosol in emergency room as well as preparation method and application of visible light photocatalytic disinfectant

Abstract

The invention belongs to the technical field of disinfection and sterilization of medical systems, and provides a visible light photocatalytic disinfectant for pathogenic bacteria attached to aerosol in an emergency room as well as a preparation method and application of the visible light photocatalytic disinfectant. Comprising composite nanoparticles of guanidine nitrate C3N4 and deionized water. Nonmetal guanidine nitrate and a C3N4-based photocatalyst are compounded, the specific antibacterial and bacteriostatic activity of guanidyl functional groups is effectively utilized, ecological risks caused by a metal-based photocatalyst are avoided, the photocatalyst is utilized to generate high reactive oxygen species (ROS), the substance metabolism process of microorganisms is persistently interfered, and the photocatalytic activity of the metal-based photocatalyst is improved. Propagation limitation and apoptosis of pathogenic bacteria are caused, and growth of beneficial bacteria is not inhibited. The disinfectant nano-particles with the photocatalytic function are convenient to apply in the form of a spray, can be directly used for disinfecting and killing by using indoor visible light resources, show a remarkable inhibition effect on pathogenic bacteria carried by aerosol particles in air in emergency wards and in four seasons, can also be sprayed on the surface of medical equipment, and can be applied to the medical equipment. And the breeding of pathogenic bacteria and the transmission of viruses can be reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical system disinfection and sterilization, and specifically relates to a visible light photocatalytic disinfectant for aerosol-attached pathogens in an emergency room, and a preparation method and application thereof. Background Art

[0002] Hospitals are the places with the highest risk level of pathogen transmission. Among the many departments in a hospital, the emergency ward is the most complicated and has the widest source of pathogens. Bacteria and viruses can generally be transmitted through droplets or aerosol particles, including various influenza viruses, allergens, endotoxins, pollen spores, etc., so the risk of cross infection in the emergency ward is also the highest. Traditional Bath disinfectant and ultraviolet disinfection methods cannot ensure the suppression of pathogens, and this has been confirmed by many previous epidemics. In terms of biological protection and inactivation control, such as the research on low-temperature plasma and nanofiltration materials, the scientific community has also made progress. In addition, there is a novel, energy-saving and environmentally friendly disinfection method that has been widely promoted, which is to capture and utilize light energy by photocatalysts for the disinfection of pathogens.

[0003] A variety of ultraviolet photocatalytic technology devices have been invented, and they are combined with ceramic membranes, glass fiber cloth, activated carbon, carbon fiber and other technologies to filter, capture and disinfect pathogens in indoor air. The application of these technologies shows the potential and practical application value of photocatalytic technology in the field of indoor medical disinfection, but the light sources used are all special ultraviolet or deep ultraviolet light generators, and the above are also the designs of complete sets of photocatalytic disinfection devices. Therefore, from another perspective, the development of photocatalytic disinfectants that are easy to carry and safe to use may be more suitable for the actual needs of "simple, effective and inexpensive".

[0004] Classic TiO2 photocatalysts mainly absorb and utilize ultraviolet light energy, while hospitals mostly use visible light resources to provide lighting for patients. A considerable number of visible light catalysts have been invented for air purification and sterilization. For example, a nanocomposite material that responds to visible light as a photocatalytic bactericidal agent [patent number CN201010609050.1] reports a complex of copper ferrite-copper cobaltate and titanium dioxide, which has a good killing effect on Escherichia coli and Staphylococcus aureus under visible light irradiation; a Z-type heterojunction photothermal catalyst for purifying organic gas pollutants in the air and inhibiting bacteria [patent number CN202110707591.6] reports a heterojunction photothermal catalyst composed of copper oxide, silver, strontium titanate or titanium dioxide; a flexible ultra-resolution photocatalyst Preparation of perylene imide polymer and its application in visible light sterilization [patent number CN202011261135.5] reports a flexible supramolecular perylene imide polymer organic semiconductor, which can completely sterilize Escherichia coli within 1 hour of irradiation with a 16-watt ordinary fluorescent lamp; a method for preparing a material with visible light catalytic purification of indoor air and sterilization [publication number CN112691683A] reports a composite material of Ag / Cu‑BiVO4 loaded on sepiolite, which has a good purification effect on indoor air pollutants and Escherichia coli. However, the above-mentioned photocatalysts mostly contain nanometal particles, which may cause secondary toxicity to humans, while the raw materials and synthesis costs of polymer organic semiconductors are relatively high, and they are more suitable for processing special profiles.

[0005] In the existing research results, graphite carbon nitride (g-C3N4) has stable physical and chemical properties and is recognized as the most biosafe visible light catalyst. In the past decade, many literatures have shown that graphite carbon nitride can photocatalytically disinfect bacteria and viruses, inhibit cancer cells using photodynamic therapy and photothermal therapy, and be used as a photoresponsive material to achieve photocontrolled drug release, cell regeneration, and sensors. However, the photocatalytic ability of the graphite phase is relatively mild, and it is often necessary to introduce heteroatoms or metal doping modifications, or form heterojunction composite catalysts with other semiconductors to improve the photocatalytic antibacterial and disinfection capabilities. For example, Bi2MoO6[doi:10.1016 / j.jhazmat.2016.09.008], m-Bi2O4[doi:10.1016 / j.apcatb.2017.05.035], AgS[doi:10.1016 / j.jece.2021.106065], AgBr[doi:10.1016 / j.jcis.2018.10.061], Ag3PO4[doi:10.3390 / catal8100406], Cu2O [doi:10.1016 / j.materresbull.2018.12.030], Fe3O4[doi:10.3390 / molecules24213888], TiO2[doi:10.1016 / j.watres.2015.05.053; doi: 10.1016 / j.jphotobiol.2017.11.009; doi:10.1007 / s10904-016-0478-4; doi:10.1016 / j.apsusc.2019.144092] and C3N4 formed heterojunction photocatalysts, polyaniline [doi:10.3390 / coatings10100950], polypyrrole [doi:10.1016 / j.jcis.2019.11.030], graphene [doi:10.1021 / acssuschemeng.7b01431], gold [doi:10.1016 / j.biomaterials.2016.10.041], silver [publication number is CN105664991A; doi:10.1021 / acsanm.8b00548; doi:10.1016 / j.chemosphere.2019.125201], vanadium [doi:10.1016 / j.apcatb.2017.11.060; doi:10.1016 / j.chemosphere.2020.128593], and carbon and oxygen [doi:10.1016 / j.jhazmat.2023.132972] doped composite photocatalysts formed by modifying C3N4.It is important to note that these studies focused on the two most common model pathogens - Escherichia coli and Staphylococcus aureus.

[0006] In addition, C3N4-based photocatalysts also showed significant inhibitory effects on some other bacteria. For example, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Salmonella [doi:10.1039 / c9nr03797g], Salmonella [doi:10.1016 / j.apcatb.2017.11.060], Pseudomonas aeruginosa, Bacillus subtilis [doi:10.1016 / j.materresbull.2018.12.030], Streptococcus pneumoniae [doi:10.1039 / c9nr03797g], Salmonella [doi:10.1016 / j.apcatb.2017.11.060], Pseudomonas aeruginosa, Bacillus subtilis [doi:10.1016 / j.materresbull.2018.12.030], Streptococcus pneumoniae [doi:10.1039 / c9nr03797g], pneumoniae [doi:10.3390 / coatings10100950], Bacillus subtilis [doi:10.1016 / j.biomaterials.2016.10.041]. Mohammad Ehtisham Khan et al.'s research even showed that Ag@g-C3N4 can be used as a potential nanomaterial to replace traditional antibiotics, cross or destroy cell walls, and has better antibacterial effect against Pseudomonas aeruginosa than streptomycin [doi:10.1021 / acsanm.8b00548]. However, photocatalysts do not necessarily exhibit antibacterial activity against all microorganisms. Ultrathin g-C3N4 nanosheets showed significant bactericidal effects against Escherichia coli and methicillin-resistant Staphylococcus aureus, but had a weaker effect on anthrax spores [doi:10.1016 / j.jcis.2017.06.089].

[0007] In addition, the above studies are limited to the simulated environment of the laboratory, and only focus on the inhibitory effect of a single or several pathogens, without considering the complexity of the real microbial ecosystem. Taking air aerosol particles as an example, the particle size distribution ranges from nanometers to dozens of microns, which may be covered with a large number of pollutants and tolerant viruses, bacteria, fungi, etc. There is even a dynamic balance of mutual dependence and mutual restraint between microorganisms. Therefore, in theory, it is unlikely to completely inhibit all microorganisms in a real environment. From the perspective of biodiversity, our goal is not to disinfect all microorganisms, but to make pathogens in a disadvantaged position in the entire microbial ecosystem, and to allow some beneficial, inert or even low-toxic species to remain. Summary of the invention

[0008] In order to solve the above problems, the present invention provides a visible light photocatalytic disinfectant for aerosol-attached pathogens in an emergency room, and a preparation method and application thereof.

[0009] The present invention is achieved by the following technical scheme: a visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room, the disinfectant comprising composite nanoparticles of guanidine nitrate C3N4 and deionized water.

[0010] The composite nanoparticles of guanidine nitrate C3N4 are prepared by the following method: (1) Urea is placed in nitrogen and heated to 580-600°C for 3-5 hours at a heating rate of 2-5°C / min to obtain slightly yellow C3N4 with a yield of 30%-35%; (2) Add 100 parts by mass of acetonitrile solvent to every 1 part by mass of C3N4, perform ultrasonic stripping at a power of 40-80 kHz for 4-6 hours, let stand for 6-8 hours, take out the upper layer of white milky turbid liquid, mix with 1.2-1.5 parts by mass of isocyanate and 0.2-0.5 parts by mass of triethylamine, heat under reflux for 24-36 hours, filter to obtain white particles, and dry under vacuum at 60°C for 16-24 hours; (3) Add 1.0-1.3 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent to 1 part by mass of the white particles obtained in step (2), grind at room temperature for 50-60 min in a nitrogen-filled glove box, and after the solvent is evaporated, heat treat at 150-180°C for 3-5 h under nitrogen protection, wash and filter with 20 parts by mass of water and ethanol, and vacuum dry at 60°C for 16-24 h to obtain guanidine nitrate C3N4.

[0011] The isocyanate in step (2) includes any one of tert-butyl isocyanate, isopropyl isocyanate, ethyl isocyanate, n-propyl isocyanate, and n-butyl isocyanate.

[0012] Furthermore, the isocyanate in step (2) is isopropyl isocyanate.

[0013] The disinfectant also includes plant fragrance, stabilizer, surfactant and alcohol.

[0014] The disinfectant is prepared from the following raw materials in parts by weight based on 100 mass fractions: 1-5 parts of composite nanoparticles of guanidine nitrate C3N4, 0.5-1 parts of plant fragrance, 1-3 parts of stabilizer, 1-3 parts of surfactant, 1-10 parts of alcohol, and the rest is deionized water. The stabilizer is polyethylene glycol 800; The plant fragrance is a herbal plant extract with antibacterial effect; the specific extraction method is: add 25-50 parts by weight of water per 1 part by weight of herbal plant, pH=2.5-3.5, heat to 45-65°C, boil for 24-36 hours, filter, extract with 15-30 parts by weight of petroleum ether twice, and concentrate the extract by rotary evaporation to obtain a transparent oily plant fragrance; The surfactant is ammonium laureth sulfate.

[0015] Furthermore, the plant fragrance is an extract of any one or any combination of mint, dandelion, wild chrysanthemum or honeysuckle.

[0016] The method for preparing the visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room is characterized by: taking composite nanoparticles of guanidine nitrate and C3N4, ultrasonicating in water for 30 to 60 minutes to obtain a dispersed mixed liquid, then adding a surfactant, a stabilizer, a plant fragrance and alcohol in sequence, and continuing to stir for 3 to 5 hours to obtain a visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room.

[0017] The present invention also provides the use of the visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room as a disinfection spray in inhibiting indoor air aerosol-attached pathogens.

[0018] Materials based on g-C3N4 are a feasible choice for developing new visible light-driven technologies to control potential pathogenic microorganisms. The present invention combines non-metallic guanidine nitrate with C3N4-based photocatalysts, which not only effectively utilizes the unique antibacterial and antimicrobial activity of the guanidine functional group, completely avoiding the ecological risks caused by metal-based photocatalysts, but also utilizes photocatalysts to generate highly active oxygen free radicals (ROS), which persistently interfere with the material metabolism process of microorganisms, resulting in restricted reproduction and apoptosis of pathogens without inhibiting the growth of beneficial bacteria.

[0019] The visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room described in the present invention is a disinfectant nanoparticle with photocatalytic function, which is compounded in the form of a spray for easy application and can directly utilize indoor visible light resources for disinfection. It shows a significant inhibitory effect on pathogens carried by air aerosol particles in emergency wards and all year round. It can also be sprayed on the surface of medical equipment, which helps to reduce the reproduction of pathogens and the spread of viruses. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The schematic diagram of the preparation of composite nanoparticles of guanidine nitrate and C3N4; Figure 2 Infrared spectra of pure C3N4 (red) and guanidine nitrate C3N4 (black); Figure 3 TG graph (left) and DTG graph (right) of pure C3N4 (black) and guanidine nitrate C3N4 (red); Figure 4 SEM characterization images of pure C3N4 (left) and guanidine nitrate C3N4 (right); Figure 5 Petri dishes for the control group (left), guanidine nitrate C3N4 (center, dark), and guanidine nitrate C3N4 (right, light); Figure 6 The histogram of species composition of microorganisms at the genus level of the samples obtained in Example 1; Figure 7 The histogram of species composition at the microbial genus level of the samples obtained in Example 3; Figure 8 It is the Alpha diversity index of the samples randomly sampled and disinfected in the emergency ward; in the figure: 1-4 are the samples collected in February, May, August and November of the same year (Application Examples 1 to 4) (**, p<0.01; ***, p<0.001). DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the disclosure and materials cited therein are hereby incorporated by reference.

[0023] Technical equivalents to the specific embodiments described that are apparent to those skilled in the art using no more than routine experimentation are intended to be encompassed by this application.

[0024] The experimental methods in the following examples are all conventional methods unless otherwise specified. The instruments and equipment used in the following examples are all conventional laboratory instruments and equipment unless otherwise specified; the experimental materials used in the following examples are all purchased from conventional biochemical reagent stores unless otherwise specified.

[0025] Example 1: A visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room, the raw materials include composite nanoparticles of guanidine nitrate and C3N4, plant fragrances, stabilizers, surfactants, water and alcohol; its components are calculated by mass fraction of 100, 5 parts of guanidine nitrate C3N4 composite nanoparticles, 3 parts of stabilizers, 1 part of plant fragrances, 3 parts of surfactants, 10 parts of alcohol, and the rest is deionized water. The preparation process is to take composite nanoparticles of guanidine nitrate and C3N4, add them to water for ultrasonic 60 minutes to obtain a dispersed mixed liquid, then add surfactants, stabilizers, plant fragrances and alcohol in sequence, and continue stirring for 5 hours to obtain a visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room.

[0026] The stabilizer is polyethylene glycol 800. The plant fragrance is a mint extract, and the preparation steps are as follows: 1 part by mass of mint is added to 25 parts by mass of water, pH=3.5, heated to 45°C and boiled for 24 hours, filtered, extracted twice with 15 parts by mass of petroleum ether, and the extract is concentrated by rotary evaporation to obtain a transparent oily plant fragrance. The surfactant is ammonium lauryl polyether sulfate.

[0027] The composite nanoparticles of guanidine nitrate and C3N4 are prepared by the following steps: (1) Weigh urea and place it in nitrogen, calcine it at 580℃ for 3h with a heating rate of 2℃ / min to obtain slightly yellow C3N4 with a yield of 35%; (2) Add 100 parts by mass of acetonitrile solvent to every 1 part by mass of C3N4, perform ultrasonic stripping at 80 kHz for 6 h, let stand for 8 h, take out the upper layer of white milky turbid liquid, mix with 1.5 parts by mass of n-butyl isocyanate and 0.5 parts by mass of triethylamine, heat and reflux for 36 h, filter to obtain white particles, and dry them in vacuum at 60 °C for 24 h; (3) For every 1 mass part of white particles, add 1.0 mass part of ammonium nitrate and 5 mass parts of ethanol solvent, grind at room temperature for 50 min in a nitrogen-filled glove box, and continue to heat the mixture at 150°C for 3 h under nitrogen protection after the solvent is evaporated. Wash and filter with 20 mass parts of water and ethanol, and vacuum dry at 60°C for 16 h to obtain guanidine nitrate C3N4.

[0028] The sample obtained in Example 1 and pure C3N4 were characterized by infrared spectroscopy. Figure 2 shown.

[0029] In the figure: The black curve is the infrared spectrum of C3N4 (abbreviated as CN) at a wave number of 800 cm -1 and 1200~1700 cm -1 There are significant infrared absorption peaks at 3380 cm-1, which are typical characteristics of the triazine ring structure of C3N4. The red curve is the infrared spectrum of guanidine nitrate C3N4 (abbreviated as GCN), and the blue curve is 3380 cm-1. -1 and 535 cm -1 The characteristic peak of 1740 cm-1 corresponds to the C-NH structure. -1 The characteristic peak of 1360 cm-1 corresponds to the C=N structure. -1 and 1675 cm -1 The characteristic peaks correspond to the N=O structure. These infrared absorption bands are different from the characteristic peaks of C3N4, proving the presence of guanidine nitrate in the composite catalyst.

[0030] Example 2: A visible light photocatalytic disinfectant for aerosol-attached pathogens in the emergency room, the raw materials of which include composite nanoparticles of guanidine nitrate and C3N4, plant fragrances, stabilizers, surfactants, water and alcohol; the components are calculated by mass fraction of 100, 4 parts of guanidine nitrate C3N4 composite nanoparticles, 2 parts of stabilizer polyethylene glycol 800, 0.8 parts of plant fragrance dandelion extract, 2 parts of surfactant ammonium lauryl polyether sulfate, 8 parts of alcohol, and the rest is deionized water. The preparation process is to take composite nanoparticles of guanidine nitrate and C3N4, add them to water and ultrasonicate for 50 minutes to obtain a dispersed mixed solution, then add surfactants, stabilizers, plant fragrances and alcohol in sequence, and continue stirring for 4 hours to obtain a visible light photocatalytic disinfectant for emergency wards.

[0031] The preparation steps of dandelion extract are as follows: 1 mass part of plant is added into 30 mass parts of water, pH=3, heated to 55°C and boiled for 30 hours, then filtered, extracted twice with 20 mass parts of petroleum ether, and the extract is concentrated by rotary evaporation to obtain a transparent oily plant fragrance.

[0032] Composite nanoparticles of guanidine nitrate and C3N4, the preparation principle is as follows Figure 1 As shown, it is prepared by the following steps: urea is pyrolyzed and calcined at 590°C in nitrogen for 4 hours at a heating rate of 3°C / min to obtain slightly yellow C3N4 with a yield of 34%; acetonitrile solvent is added to C3N4, and ultrasonic stripping is performed at a power of 60kHz for 5 hours. After standing for 7 hours, the upper white milky turbid liquid is taken, 1.4 parts by mass of n-propyl isocyanate and 0.4 parts by mass of triethylamine are mixed, and the mixture is heated under reflux for 32 hours, and white particles are obtained by filtration, and vacuum drying is performed at 60°C for 20 hours; Add 1.2 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent, grind at room temperature for 55 minutes, and after the solvent is evaporated, continue to heat it to 170°C under nitrogen protection for 4 hours, and vacuum dry it at 60°C for 18 hours. The rest of the method is the same as that described in Example 1 to obtain guanidine nitrate C3N4.

[0033] The sample obtained in Example 2 and pure C3N4 were characterized by TG-DTG. The results are as follows Figure 3 shown.

[0034] In the figure: the left is the TG thermogravimetric analysis graph, the right is the DTG differential thermal analysis graph, the black curve is C3N4 (abbreviated as CN), and the red curve is guanidine nitrate C3N4 (abbreviated as GCN). Comparing the TG and DTG curves of the two, it is confirmed that the thermal gravimetric curve of the guanidine nitrate C3N4 composite photocatalyst is significantly different from that of C3N4, which is one of the evidences of the successful preparation of the former.

[0035] Example 3: A visible light photocatalytic disinfectant for aerosol-attached pathogens in the emergency room, wherein the raw materials include composite nanoparticles of guanidine nitrate and C3N4, plant fragrance, stabilizer, surfactant ammonium lauryl polyether sulfate, water and alcohol; the components are calculated by mass fraction of 100, 3 parts of guanidine nitrate C3N4 composite nanoparticles, 2 parts of stabilizer polyethylene glycol 800, 0.6 parts of plant fragrance wild chrysanthemum extract, 2 parts of surfactant ammonium lauryl polyether sulfate, 4 parts of alcohol, and the rest is deionized water. The preparation process is to take composite nanoparticles of guanidine nitrate and C3N4, add them to water and ultrasonicate for 40 minutes to obtain a dispersed mixed solution, then add surfactant, stabilizer, plant fragrance and alcohol in sequence, and continue stirring for 4 hours to obtain a visible light photocatalytic disinfectant for emergency wards.

[0036] The preparation steps of wild chrysanthemum extract are as follows: 1 mass part of plant is added into 40 mass parts of water, pH=2.5, heated to 50°C and boiled for 32 hours, then filtered, extracted twice with 25 mass parts of petroleum ether, and the extract is concentrated by rotary evaporation to obtain a transparent oily plant fragrance.

[0037] The composite nanoparticles of guanidine nitrate and C3N4 are prepared by the following steps: urea is placed in nitrogen, thermally calcined at 590°C for 4 hours, and the heating rate is 4°C / min to obtain slightly yellow C3N4 with a yield of 33%; C3N4 acetonitrile solvent is ultrasonically stripped at 40kHz power for 5 hours, and after standing for 6 hours, the upper white milky turbid liquid is taken, 1.3 parts by mass of tert-butyl isocyanate and 0.3 parts by mass of triethylamine are mixed, heated to reflux reaction for 28 hours, filtered to obtain white particles, and vacuum dried for 18 hours; 1.2 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent are added to the white particles, ground at room temperature for 60 minutes in a nitrogen-filled glove box, and after the solvent is evaporated, the temperature is continuously raised to 160°C for heat treatment for 4 hours under nitrogen protection, washed and filtered with 20 parts by mass of water and ethanol, and vacuum dried at 60°C for 20 hours. The remaining methods are the same as those described in Example 1 to obtain guanidine nitrate C3N4.

[0038] Example 4: A visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room, the raw materials of which include composite nanoparticles of guanidine nitrate and C3N4, plant fragrance honeysuckle extract, stabilizer polyethylene glycol 800, surfactant ammonium lauryl polyether sulfate, water and alcohol; the components are calculated by mass fraction of 100, 1 part of guanidine nitrate C3N4 composite nanoparticles, 1 part of stabilizer, 0.5 part of plant fragrance, 1 part of surfactant, 1 part of alcohol, and the rest is deionized water. The preparation process is to take composite nanoparticles of guanidine nitrate and C3N4, add them to water for ultrasonication for 30 minutes to obtain a dispersed mixed solution, then add surfactants, stabilizers, plant fragrances and alcohol in sequence, and continue stirring for 3 hours to obtain a visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room.

[0039] The preparation steps of honeysuckle extract are as follows: add 50 parts by weight of water per 1 part by weight of plant, pH=2.5, heat to 65°C, boil for 36 hours, filter, extract twice with 30 parts by weight of petroleum ether, and concentrate the extract by rotary evaporation to obtain a transparent oily plant fragrance.

[0040] The composite nanoparticles of guanidine nitrate and C3N4 are prepared by the following steps: urea is placed in nitrogen, thermally calcined at 600°C for 5h, and the heating rate is 5°C / min to obtain slightly yellow C3N4 with a yield of 30%; acetonitrile solvent is added to C3N4, and ultrasonic stripping is performed at a power of 40kHz for 4h. After standing for 6h, the upper white milky turbid liquid is taken, 1.2 parts by mass of isopropyl isocyanate and 0.2 parts by mass of triethylamine are mixed, and the mixture is heated under reflux for reaction for 24h, filtered to obtain white particles, and vacuum dried at 60°C for 16h; 1.3 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent are added to the white particles, and the mixture is ground at room temperature for 60min in a nitrogen-filled glove box. After the solvent is evaporated, the mixture is heated to 180°C for heat treatment for 5h under nitrogen protection, washed and filtered with 20 parts by mass of water and ethanol, and vacuum dried at 60°C for 24h. The remaining methods are the same as those described in Example 1 to obtain guanidine nitrate C3N4.

[0041] The samples obtained in Example 4 and pure C3N4 were characterized by SEM electron microscopy. Figure 4 shown.

[0042] In the figure: The electron microscope photograph of the guanidine nitrate C3N4 composite photocatalyst (right) is similar to that of C3N4 (left), proving that the introduction of guanidine nitrate will not change the morphological characteristics of C3N4.

[0043] Corresponding to the above four embodiments, four application examples are given.

[0044] Application Example 1: On a certain day in February, random ward sampling was carried out in the emergency ward (the patient had left for at least one day for routine disinfection and ultraviolet sterilization), and a liquid impact microbial aerosol sampler was used to sample indoor aerosol particles. Indoor aerosol particles were collected. The test results are shown in Table 1, and the samples were placed in a refrigerator for standby use. Quantitative trace samples were taken and cultured on culture dishes, beef extract peptone agar culture medium. At least three groups of parallel experiments (3-5 culture dishes in each group) were set up, divided into a control group (no catalyst), a dark experiment group (sprayed with the photocatalytic disinfectant described in Example 1, without light), and an illumination experiment group (sprayed with the photocatalytic disinfectant described in Example 1, with light). Move to a constant temperature microbial incubator for culture at 37°C, observe and record at 24h and 48h respectively, scrape samples with a sterilized spoon during the most active period of bacterial production, store them in dry ice at -20°C, and perform high-throughput analysis of microbial species changes by bacterial 16s V3V4 diversity. The test results are shown in Figure 6 .

[0045] Figure 6 The figure is a horizontal bar graph of microbial species of the samples obtained in Example 1 (CK is the control group, and sample 1 is tested twice in parallel).

[0046] Figure: The 20 microbial species with the highest detection levels in the control group include MBNT15 (a type of Desulfurobacterium), Romboutsia, Pseudogracilibacillus, 0319−6G20 (an unknown Proteus), Subgroup_10 (an unknown subspecies), Ellin6067 (an unknown Proteus), Sporosarcina, Helicobacter pylori, Pseudomonas, Rhodococcus, Comamonas, Noviherbaspirillum, Pantoea, Cupriavidus, Lactobacillus s (Lactobacillus), Sphingomonas (Sphingomonas), Allorhizobium−Neorhizobium−Pararhizobium−Rhizobium (a kind of rhizobium), Bacillus (Bacillus), Herbaspirillum (Grass Spiral), Burkholderia−Caballeronia−Paraburkholderia (Burkholderia-Caballeronia-Paraburkholderia), these bacteria mostly belong to the living space of patients with intestinal diseases, reproductive system infections, immune system infections, lung infectious diseases, etc. However, after the composite photocatalyst disinfection, the diversity of microbial species attached to aerosol particles decreased significantly, and the harmful bacteria that dominated the control group were all weakened or even disappeared, and replaced by Burkholderia genus to occupy the main position. Most of this genus of bacteria appear in natural medicines and plant growth environments (doi:10.1007 / s00248-011-9929-1; doi: 10.1007 / s00253-016-7520-x; 10.1021 / acs.jnatprod.8b01068), promoting plant growth, biological nitrogen fixation, secreting antibiotics, preventing diseases and pests, and being used for microbial synthesis of chemicals or degradation of aromatic hydrocarbon pollutants (patent publication number CN 117757690 A; publication number CN 116024136 A; authorization number 202410443471.3).

[0047] Application Example 2: On a certain day in May, random ward sampling was carried out in the emergency ward (the patient had been away for at least one day for routine disinfection and ultraviolet sterilization), and a liquid impact microbial aerosol sampler was used to sample indoor aerosol particles. The indoor aerosol particles were collected. The test results are shown in Table 1. The samples were placed in a refrigerator for standby use. Quantitative trace samples were taken and cultured on culture dishes, beef extract peptone agar culture medium. At least three groups of parallel experiments were set up (3-5 culture dishes in each group), divided into a control group (no catalyst), a dark experiment group (sprayed with the photocatalytic disinfectant described in Example 2, without light), and an illumination experiment group (sprayed with the photocatalytic disinfectant described in Example 2, with light), and photos were taken for reference Figure 5 The samples were moved to a constant temperature microbial incubator and cultured at 37°C. Observations and records were made at 24 and 48 hours. Samples were scraped with a sterilized spoon during the most active period of bacterial production and stored in dry ice at -20°C. The changes in microbial species were analyzed by bacterial 16s V3V4 diversity high-throughput analysis.

[0048] Figure 5 Petri dishes showing the control (left), guanidine nitrate C3N4 (center, dark), and guanidine nitrate C3N4 (right, light).

[0049] In the figure: In the culture dish of the control group without catalyst (left), white bacteria of different sizes were found. When guanidine nitrate C3N4 (middle) was added without light, the white bacteria were inhibited and grew into a light green bacterial band. Finally, in the culture dish of guanidine nitrate C3N4 (right) with light turned on, a more obvious light green bacterial band appeared. This experiment can intuitively show that the photocatalyst can inhibit the white dominant bacteria in the control group, and the white dominant bacteria are mostly harmful bacteria according to the subsequent microbial diversity. The photocatalyst promotes the growth of light green weak bacteria, and the light green weak bacteria are mostly beneficial bacteria according to the subsequent microbial diversity.

[0050] Application Example 3: On a certain day in August, random ward sampling was carried out in the emergency ward (the patient had left for at least one day for routine disinfection and ultraviolet sterilization), and a liquid impact microbial aerosol sampler was used to sample indoor aerosol particles. Indoor aerosol particles were collected. The test results are shown in Table 1, and the samples were placed in a refrigerator for standby use. Quantitative trace samples were taken and cultured on culture dishes, beef extract peptone agar culture medium. At least three groups of parallel experiments were set up (3-5 culture dishes in each group), divided into a control group (no catalyst), a dark experiment group (sprayed with the photocatalytic disinfectant described in Example 3, without light), and an illumination experiment group (sprayed with the photocatalytic disinfectant described in Example 3, with light). Move to a constant temperature microbial incubator for culture at 37°C, observe and record at 24h and 48h respectively, scrape samples with a sterilized spoon during the most vigorous period of bacterial production, store them in dry ice at -20°C, and perform high-throughput analysis of microbial species changes by bacterial 16s V3V4 diversity. The test results are shown in Figure 7 .

[0051] Figure 7 Species-level bar chart of the samples obtained in Example 3 (CK is the control group, sample 3 was tested twice in parallel).

[0052] Figure: The 20 microbial species with the highest detection levels in the control group include Dechloromonas, Cetobacterium, Faecalibacterium, Citrobacter, RBG−16−58−14, Escherichia−Shigella, Serratia, Candidatus_Amoebophilus, Limosilactobacillus, Exiguobacterium, Rhodococcus, and Rhodococcus), Pedobacter, Stenotrophomonas, Chryseobacterium, Pseudomonas, Brevundimonas, Lactococcus, Acinetobacter, Macrococcus, Burkholderia-Caballeronia-Paraburkholderia, most of these bacteria belong to the living space of patients with intestinal diseases, urinary tract infections, blood infections, traumatic infections, and pulmonary infectious diseases. However, after the composite photocatalyst disinfection, the diversity of microbial species attached to the aerosol particles decreased significantly, and the harmful bacteria that dominated the control group were all weakened or even disappeared, and were replaced by Burkholderia, which dominated the control group.

[0053] Application Example 4: On a certain day in November, random ward sampling was carried out in the emergency ward (the patient left for at least one day for routine disinfection and ultraviolet sterilization), and a liquid impact microbial aerosol sampler was used to sample indoor aerosol particles, and indoor aerosol particles were collected. The test results are shown in Table 1, and the samples were placed in a refrigerator for standby. Quantitative trace samples were cultured on culture dishes, beef extract peptone agar medium. At least three groups of parallel experiments (3-5 culture dishes per group) were set up, divided into a control group (no catalyst), a dark experiment group (sprayed with the photocatalytic disinfectant described in Example 4, without light), and an illumination experiment group (sprayed with the photocatalytic disinfectant described in Example 4, with light). Move to a constant temperature microbial incubator for culture at 37°C, observe and record at 24h and 48h respectively, scrape samples with a sterilized spoon during the most vigorous period of bacterial production, store them in dry ice at -20°C, and analyze the changes in microbial species by high-throughput analysis of bacterial 16s V3V4 diversity.

[0054] Collect the diversity test results of application examples 1 to 4, see Figure 8 shown.

[0055] In the figure: 1-4 are samples collected in February, May, August, and November of the same year (Application Examples 1 to 4). The diversity index of microorganisms attached to indoor aerosol particles by the guanidine nitrate C3N4 composite photocatalyst (light and dark groups) was significantly lower than that of the control group, indicating that the guanidine group on the surface of the guanidine nitrate C3N4 composite photocatalyst in the dark environment has certain antibacterial properties, and its surface charge is conducive to the contact between the catalyst and the bacterial wall, destroying the metabolic function of the enzyme in the cell membrane, but the composite photocatalyst performs better after illumination, proving that the photogenerated electrons and holes on the catalyst surface continue to affect the bacterial wall, and the photogenerated free radicals can also participate in inhibiting the metabolic function of microorganisms.

[0056] Combination Figure 5 The analysis showed that the bacterial growth in the control group was not as good as that in the experimental group, but its species diversity was higher; the bacterial growth in the experimental group was better than that in the control group, but its species diversity decreased significantly. Analysis showed that after adding the photocatalyst, the reproduction of harmful microorganisms was indeed inhibited. The light conditions were worse than the dark conditions, which led to changes in the dynamic balance of microorganisms in the culture dish. The reproduction of beneficial bacteria such as Burkholderia would compress the living space of harmful microorganisms. It can also be considered that the restricted growth of harmful microorganisms stimulated the reproduction of other bacteria such as Burkholderia.

[0057] Aerosol particles collected in the emergency room were cultured for microbial species diversity analysis: Aerosol particles collected in the emergency room were cultured. Beef extract peptone agar medium formula (refer to "Microbial Pharmaceutical Technology" (Edited by Wu Xiuling and Li Gongbin, China Light Industry Press, 2025) beef extract 3.0g, peptone 10.0g, sodium chloride 5.0g, agar 15-25g, water 1000ml, pH: 7.4-7.6.

[0058] Specific process: 30 mL of culture medium was introduced into each culture dish, and 100 μL of aerosol particles were added for inoculation. All experiments were divided into two groups: a control group with only 100 μL of aerosol particles added, and an experimental group with 100 μL of aerosol particles and 100 μL of photocatalytic disinfectant added. All culture dishes were placed under 75W LED light with a color temperature of 6000K-9000K, a light efficiency of 93Lm / W, and a light source diameter of 90mm for 2-3 hours, and finally moved to a constant temperature microbial incubator for culture at 37°C, and observed and recorded at 24h and 48h respectively. Collect the microorganisms cultured on the plate, scrape them off the plate with a sterilized spoon during the most vigorous period of bacterial production, place them in a 1.5 or 2.0ml centrifuge tube, quickly freeze the centrifuge tube in liquid nitrogen for about 10 minutes, and then transfer to -20°C dry ice for storage, and analyze the changes in microbial species by high-throughput analysis of bacterial 16s V3V4 diversity. The results of aerosol particle collection in the emergency ward are shown in Table 1.

[0059] Table 1 Aerosol particle test of samples obtained from four seasons sampling According to [Particle•Microbial Aerosol Sampling and Analysis (GB / T38517-2020)], a liquid impact microbial aerosol sampler is used to sample and analyze indoor aerosol particles. The test height is 1m, the sampling time is 120min, the flow rate is 8.5L / min, and the collection medium is sterilized ultrapure water filtered by a microfiltration membrane. 1-4 are samples collected in February, May, August, and November of the same year, respectively, and 0 is the clean space background value of non-hospital wards. As can be seen from the table, although the emergency ward has undergone routine disinfection and ultraviolet sterilization, there are still considerable concentrations of aerosol particles remaining indoors. These aerosol particles provide carriers for the attachment of pathogenic microorganisms and viruses. The organic pollutants on the particles even provide certain nutrients for the survival of the bacteria, which objectively creates a high risk of transmission of epidemic bacteria and viruses in confined spaces.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A visible light catalytic disinfectant for aerosol-attached pathogens in emergency rooms, characterized by: The disinfectant comprises composite nanoparticles of guanidine nitrate C3N4 and deionized water.

2. The visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room according to claim 1, characterized in that: The composite nanoparticles of guanidine nitrate C3N4 are prepared by the following method: (1) Urea is placed in nitrogen and heated to 580-600°C for 3-5 hours at a heating rate of 2-5°C / min to obtain slightly yellow C3N4 with a yield of 30%-35%; (2) Add 100 parts by mass of acetonitrile solvent to every 1 part by mass of C3N4, perform ultrasonic stripping at a power of 40-80 kHz for 4-6 hours, let stand for 6-8 hours, take out the upper layer of white milky turbid liquid, mix with 1.2-1.5 parts by mass of isocyanate and 0.2-0.5 parts by mass of triethylamine, heat under reflux for 24-36 hours, filter to obtain white particles, and dry under vacuum at 60°C for 16-24 hours; (3) Add 1.0-1.3 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent to 1 part by mass of the white particles obtained in step (2), grind at room temperature for 50-60 min in a nitrogen-filled glove box, and after the solvent is evaporated, heat treat at 150-180°C for 3-5 h under nitrogen protection, wash and filter with 20 parts by mass of water and ethanol, and vacuum dry at 60°C for 16-24 h to obtain guanidine nitrate C3N4.

3. The visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room according to claim 2, characterized in that: The isocyanate in step (2) includes any one of tert-butyl isocyanate, isopropyl isocyanate, ethyl isocyanate, n-propyl isocyanate, and n-butyl isocyanate.

4. The visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room according to claim 3, characterized in that: The isocyanate in step (2) is isopropyl isocyanate.

5. The visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room according to claim 1, characterized in that: The disinfectant also includes plant fragrance, stabilizer, surfactant and alcohol.

6. The visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room according to claim 5, characterized in that: The disinfectant is prepared from the following raw materials in parts by weight based on 100 mass fractions: 1-5 parts of composite nanoparticles of guanidine nitrate C3N4, 0.5-1 parts of plant fragrance, 1-3 parts of stabilizer, 1-3 parts of surfactant, 1-10 parts of alcohol, and the rest is deionized water.

7. The visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room according to claim 6, characterized in that: The stabilizer is polyethylene glycol 800; The plant fragrance is a herbal plant extract with antibacterial effect; the specific extraction method is: add 25-50 parts by weight of water per 1 part by weight of herbal plant, pH=2.5-3.5, heat to 45-65°C, boil for 24-36 hours, filter, extract with 15-30 parts by weight of petroleum ether twice, and concentrate the extract by rotary evaporation to obtain a transparent oily plant fragrance; The surfactant is ammonium laureth sulfate.

8. The visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room according to claim 7, characterized in that: The plant aromatic is an extract of any one or any combination of mint, dandelion, wild chrysanthemum or honeysuckle.

9. A method for preparing a visible light catalytic disinfectant for aerosol-attached pathogens in emergency rooms as claimed in any one of claims 1 to 3, characterized in that: Take the composite nanoparticles of guanidine nitrate and C3N4, ultrasonicate them in water for 30-60 min to obtain a dispersed mixed solution, then add surfactants, stabilizers, plant fragrances and alcohol in sequence, and continue stirring for 3-5 hours to obtain a visible light catalytic disinfectant for aerosol-attached pathogens in the emergency room.

10. Use of the visible light catalytic disinfectant for aerosol-attached pathogens in emergency rooms as claimed in any one of claims 1 to 8 as a disinfection spray in inhibiting indoor air aerosol-attached pathogens.

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