A visible light photocatalytic disinfectant for aerosol attached pathogenic bacteria in an emergency room and a preparation method and application thereof

Abstract

The application belongs to the technical field of disinfection and sterilization of medical systems, and provides a visible light photocatalytic disinfectant for aerosol attached pathogenic bacteria in emergency rooms as well as a preparation method and application thereof. The disinfectant comprises composite nanoparticles of guanidine nitrate C3N4 and deionized water. The non-metallic guanidine nitrate is compounded with the C3N4-based photocatalyst, the antibacterial and bacteriostatic activity of the guanidino functional group is effectively utilized, the ecological risk caused by the metal-based photocatalyst is avoided, the high active oxygen free radicals ROS generated by the photocatalyst are utilized to persistently interfere with the material metabolism of microorganisms, and the reproduction of pathogenic bacteria is limited and apoptosis occurs without inhibiting the growth of beneficial bacteria. The disinfectant nanoparticles with photocatalytic function are in the form of a spray, are convenient to apply, can be directly disinfected by using indoor visible light resources, show a significant inhibitory effect on pathogenic bacteria carried by aerosol particulate matters in emergency rooms and in all seasons, and can be sprayed on the surface of medical equipment to help reduce the reproduction of pathogenic bacteria and the spread of viruses.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of disinfection and sterilization of medical systems, and particularly relates to a visible light photocatalytic disinfectant for aerosol-attached pathogenic bacteria in an emergency room, a preparation method and application thereof. BACKGROUND

[0002] Hospitals are places where pathogens are transmitted at the highest risk level. Among the many departments in a hospital, the emergency ward is the most complex and has the most sources of pathogens. Bacteria and viruses can generally be transmitted through droplets or aerosol particles, including various influenza viruses, allergens, endotoxins, pollen spores, and the like. Therefore, the emergency ward has the highest risk of cross-infection. Traditional BAS disinfectant and ultraviolet disinfection methods cannot ensure the inhibition of pathogenic bacteria, and previous epidemics have confirmed this. In the field of biological protection and inactivation control, such as low-temperature plasma and nanofiltration materials, the scientific community has made progress. In addition, a novel, energy-saving and environmentally friendly disinfection method has been widely promoted, which is to capture and utilize light energy with photocatalysts for the disinfection of pathogenic bacteria.

[0003] A variety of ultraviolet photocatalytic technology devices have been invented, and combined with ceramic membranes, fiberglass cloth, activated carbon, carbon fiber and other technologies to filter, capture and disinfect indoor air pathogens. The application of these technologies has shown the potential and practical application value of photocatalytic technology in the field of indoor medical disinfection, but the light sources used are special ultraviolet or deep ultraviolet light generators, and the photocatalytic disinfection devices are also designed as a complete set. 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 "simplicity and frugality".

[0004] The classic TiO2 photocatalyst mainly absorbs and utilizes ultraviolet light energy, while the hospital indoor lighting for patients is mostly visible light resources. A considerable number of visible light catalysts have been invented for air purification and sterilization. For example, the application of a nano-composite material responsive to visible light as a photocatalytic bactericide [patent number CN201010609050.1] reported that the composite of copper ferrite-cobalt copper and titanium dioxide had good killing effect on Escherichia coli and Staphylococcus under visible light irradiation; a Z-type heterojunction photo-thermal catalyst for purifying air organic gas pollutants and inhibiting bacteria [patent number CN202110707591.6] reported a heterojunction photo-thermal catalyst composed of copper oxide, silver, strontium titanate or titanium dioxide; the preparation of a flexible supramolecular perylene imide polymer and its application in visible light sterilization [patent number CN202011261135.5] reported a flexible supramolecular perylene imide polymer organic semiconductor, which could completely sterilize Escherichia coli within 1 h of 16-watt ordinary daylight lamp irradiation; a material preparation method with visible light catalytic purification of indoor air and sterilization [publication number CN112691683A] reported a composite material of Ag / Cu-BiVO4 loaded on sepiolite, which had good purification effect on indoor air pollutants and Escherichia coli. However, the above-mentioned photocatalysts mostly contain nano metal particles, which may cause secondary toxicity to humans, and the raw materials and synthesis cost of polymer organic semiconductors are relatively high, which are more suitable for processing of special profiles.

[0005] Among the existing research results, graphite phase carbon nitride (g-C3N4) has stable physical and chemical properties and is considered to be the most biologically safe visible light catalyst. In the past decade, many documents have shown that graphite phase carbon nitride can photocatalyze bacteria and viruses, inhibit cancer cells by photodynamic therapy and photothermal therapy, and realize light-controlled drug release, cell regeneration, and sensors as a light-responsive material. However, the photocatalytic ability of graphite phase is relatively mild, and it is often necessary to introduce heteroatoms or metal doping modification or form heterojunction composite catalysts with other semiconductors to improve the photocatalytic bacteriostatic and disinfecting ability. 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] heterojunction photocatalysts with C3N4, 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 [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], carbon oxygen [doi:10.1016 / j.jhazmat.2023.132972] doped and modified C3N4 composite photocatalysts.It must be pointed out that these studies are mainly aimed at the two most common model pathogens - Escherichia coli and Staphylococcus aureus.

[0006] In addition, C3N4-based photocatalysts also show significant inhibition effect on 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:10.3390 / coatings10100950], Bacillus subtilis [doi:10.1016 / j.biomaterials.2016.10.041]. Mohammad Ehtisham Khan et al. study even shows that Ag@g-C3N4 can be a potential alternative to traditional antibiotics nanomaterials, crossing or destroying the cell wall, and the antibacterial effect on Pseudomonas aeruginosa is better than that of streptomycin [doi:10.1021 / acsanm.8b00548]. However, photocatalysts do not necessarily show antibacterial activity to all microorganisms. Ultra-thin g-C3N4 nanosheets show significant bactericidal effect on Escherichia coli and methicillin-resistant Staphylococcus aureus, but weak bactericidal effect on Bacillus anthracis spores [doi:10.1016 / j.jcis.2017.06.089].

[0007] In addition, the above studies are limited to laboratory simulation environment, only for the inhibition effect of single or several pathogenic bacteria, and do not consider the complexity of the real microbial ecosystem. For example, air aerosol particles have a particle size distribution ranging from nanometers to tens of microns, and may contain a large number of pollutants and resistant viruses, bacteria, fungi and other microorganisms. There is a dynamic balance between microorganisms, so theoretically it is difficult to completely inhibit all microorganisms in the real environment. From the perspective of biological diversity, our goal is not to kill all microorganisms, but to make pathogenic bacteria in the entire microbial ecosystem in a weak position, and to allow some beneficial, inert or low-toxicity species to remain. SUMMARY

[0008] The present application provides a visible light photocatalytic disinfectant for aerosol attached pathogenic bacteria in an emergency room, a preparation method and application thereof.

[0009] The present application is realized by the following technical solutions: a visible light photocatalytic disinfectant for aerosol attached pathogenic bacteria in an 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:

[0011] (1) Urea is placed in nitrogen, heated to 580-600℃ at a heating rate of 2-5℃ / min, and pyrolyzed and calcined for 3-5h to obtain a yellowish C3N4 with a yield of 30%-35%;

[0012] (2) 100 parts by mass of acetonitrile solvent is added to every 1 part by mass of C3N4, ultrasonic stripping is performed at a power of 40-80kHz for 4-6h, and after standing for 6-8h, the upper layer of white milk-like turbid liquid is taken, 1.2-1.5 parts by mass of isocyanate and 0.2-0.5 parts by mass of triethylamine are mixed, and heated reflux reaction is performed for 24-36h, white particles are obtained by filtration, and vacuum drying is performed at 60℃ for 16-24h;

[0013] (3) 1.0-1.3 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent are added to the white particles obtained in step (2), grinding is performed at room temperature in a nitrogen-filled glove box for 50-60min, after the solvent is volatilized and dried, heating is continued to 150-180℃ under nitrogen protection for 3-5h, washing and filtering are performed with 20 parts by mass of water and ethanol, and vacuum drying is performed at 60℃ for 16-24h to obtain guanidine nitrate C3N4.

[0014] The isocyanate in step (2) includes any one of tert-butyl isocyanate, isopropyl isocyanate, ethyl isocyanate, n-propyl isocyanate and n-butyl isocyanate.

[0015] Further, the isocyanate in step (2) is isopropyl isocyanate.

[0016] The disinfectant also comprises a plant fragrance, a stabilizer, a surfactant, and alcohol.

[0017] The disinfectant is prepared from the following raw materials in parts by weight: 1-5 parts of guanidine nitrate C3N4 composite nanoparticles, 0.5-1 part of a plant fragrance, 1-3 parts of a stabilizer, 1-3 parts of a surfactant, 1-10 parts of alcohol, and the rest is deionized water, all by mass fraction.

[0018] The plant fragrance is a herbal plant extract with antibacterial efficacy; the specific extraction method is as follows: 1 part by mass of a herbal plant is added to 25-50 parts by mass of water, the pH is adjusted to 2.5-3.5, and the mixture is heated to 45-65℃ for 24-36 h of decoction, then filtered, and extracted twice with 15-30 parts by mass of petroleum ether, and the extract is concentrated by rotary evaporation to obtain a transparent oily plant fragrance.

[0019] The surfactant is ammonium laureth sulfate.

[0020] Further, the plant fragrance is an extract of any one or any combination of peppermint, dandelion, wild chrysanthemum, or honeysuckle.

[0021] The method for preparing the visible light catalytic disinfectant for aerosol-attached pathogenic bacteria in an emergency room is characterized by the following steps: taking guanidine nitrate and C3N4 composite nanoparticles, ultrasonically dispersing them in water for 30-60 min to obtain a dispersion mixture, then sequentially adding a surfactant, a stabilizer, a plant fragrance, and alcohol, and continuing to stir for 3-5 h to obtain the visible light catalytic disinfectant for aerosol-attached pathogenic bacteria in an emergency room.

[0022] The application also provides the use of the visible light catalytic disinfectant for aerosol-attached pathogenic bacteria in an emergency room as a disinfectant spray for inhibiting aerosol-attached pathogenic bacteria in indoor air.

[0023] The g-C3N4-based material is a viable option for developing new visible light-driven technologies to control potential pathogenic microorganisms, and the application uses non-metallic guanidine nitrate and C3N4-based photocatalysts to compound, which not only effectively utilizes the unique antibacterial and bacteriostatic activity of the guanidino functional group, completely avoids the ecological risks caused by metal-based photocatalysts, but also utilizes the high activity of oxygen free radicals (ROS) generated by the photocatalyst to persistently interfere with the material metabolism process of microorganisms, leading to limited reproduction and apoptosis of pathogenic bacteria without inhibiting the growth of beneficial bacteria.

[0024] The visible light catalytic disinfectant for pathogens attached to aerosols in emergency rooms described in this invention consists of disinfectant nanoparticles with photocatalytic function. It is conveniently applied in the form of a spray and can directly utilize indoor visible light resources for disinfection. It shows a significant inhibitory effect on pathogens carried by aerosol particles in emergency wards and throughout the year. It can also be sprayed on the surface of medical equipment to help reduce the reproduction of pathogens and the spread of viruses. Attached Figure Description

[0025] Figure 1 A schematic diagram illustrating the preparation principle of composite nanoparticles of guanidine nitrate and C3N4;

[0026] Figure 2 Infrared spectra of pure C3N4 (red) and guanidine nitrate C3N4 (black);

[0027] Figure 3 TG plot (left) and DTG plot (right) for pure C3N4 (black) and guanidine nitrate C3N4 (red);

[0028] Figure 4 SEM images of pure C3N4 (left) and guanidine nitrate C3N4 (right);

[0029] Figure 5 Culture dishes for the control group (left), guanidine nitrate C3N4 (middle, dark), and guanidine nitrate C3N4 (right, under light);

[0030] Figure 6 This is a bar chart showing the microbial species composition of the samples obtained in Example 1.

[0031] Figure 7 This is a bar chart showing the microbial species composition of the samples obtained in Example 3.

[0032] Figure 8 Alpha diversity index of randomly sampled disinfection samples in the emergency ward; In the figure: 1-4 are samples collected in February, May, August and November of the same year, respectively (Application Examples 1-4) (**, p<0.01; ***, p<0.001). Detailed Implementation

[0033] To make the objectives, 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 some embodiments of the present invention, but 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.

[0034] Unless otherwise defined, 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 application belongs, and the materials described herein will be referred to by the names given to them in the references cited herein and throughout the specification.

[0035] All equivalents of the described specific embodiments, which would be apparent to those skilled in the art upon a consideration of this disclosure, are intended to be encompassed by the present application.

[0036] The experimental methods in the following examples are all routine methods unless otherwise specified. The instruments and equipment used in the following examples are all routine laboratory instruments and equipment unless otherwise specified; the experimental materials used in the following examples are all purchased from routine biochemical reagent stores unless otherwise specified.

[0037] Example 1: A visible light catalytic disinfectant for aerosol-attached pathogenic bacteria in an emergency room, raw materials including guanidine nitrate and C3N4 composite nanoparticles, plant fragrance, stabilizer, surfactant, water and alcohol; its components are 5 parts of guanidine nitrate C3N4 composite nanoparticles, 3 parts of stabilizer, 1 part of plant fragrance, 3 parts of surfactant, 10 parts of alcohol, and the rest is deionized water, by mass fraction. The preparation process is as follows: take guanidine nitrate and C3N4 composite nanoparticles, add water and ultrasonic for 60 min to get a dispersion mixture, then add surfactant, stabilizer, plant fragrance and alcohol in turn, continue to stir for 5 h, and get a visible light catalytic disinfectant for aerosol-attached pathogenic bacteria in an emergency room.

[0038] The stabilizer is polyethylene glycol 800. The plant fragrance is a mint extract, and its preparation steps are as follows: add 25 parts of water to 1 part of mint, pH = 3.5, heat to 45℃ and soak for 24 h, then filter, extract twice with 15 parts of petroleum ether, concentrate the extract liquid by rotary evaporation, and get a transparent oil plant fragrance. The surfactant is ammonium laureth sulfate.

[0039] Guanidine nitrate and C3N4 composite nanoparticles are prepared by the following steps:

[0040] (1) Take urea and place it in nitrogen, pyrolyze and calcine at 580℃ for 3h with a heating rate of 2℃ / min, obtain yellowish C3N4 with a yield of 35%;

[0041] (2) Add 100 parts of acetonitrile solvent to 1 part of C3N4, ultrasonic stripping at 80 kHz power for 6h, take the upper layer white milk-like turbid liquid after standing for 8h, mix 1.5 parts of n-butyl isocyanate and 0.5 parts of triethylamine, heat reflux reaction for 36h, filter to obtain white particles, and vacuum dry at 60℃ for 24h;

[0042] (3) 1.0 part by mass of ammonium nitrate and 5 parts by mass of ethanol solvent were added to 1 part by mass of the white particles, and the mixture was ground in a nitrogen-filled glove box at room temperature for 50 minutes. After the solvent was evaporated, the mixture was heated to 150°C under nitrogen for 3 hours. The mixture was washed with 20 parts by mass of water and ethanol, and filtered. The filter cake was dried in a vacuum at 60°C for 16 hours to obtain guanidine nitrate C3N4.

[0043] The sample obtained in Example 1 and pure C3N4 were characterized by infrared spectroscopy, and the results are shown in FIG. 1. Figure 2

[0044] In the figure, the black curve is the infrared spectrum of C3N4 (abbreviated as CN), and there are significant infrared absorption peaks at wave numbers of 800 cm -1 and 1200-1700 cm -1 . These absorption peaks 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 characteristic peaks marked in blue at 3380 cm -1 and 535 cm -1 correspond to the C-NH structure, the characteristic peak at 1740 cm -1 corresponds to the C=N structure, and the characteristic peaks at 1360 cm -1 and 1675 cm -1 correspond to the N=O structure. These infrared absorption bands are characteristic peaks that distinguish C3N4, proving the presence of guanidine nitrate in the composite catalyst.

[0045] Example 2: A visible light catalytic disinfectant for aerosol-attached pathogenic bacteria in an emergency room, which comprises guanidine nitrate and C3N4 composite nanoparticles, plant fragrance, stabilizer, surfactant, water and alcohol. The components are as follows in terms of 100 parts by mass: guanidine nitrate C3N4 composite nanoparticles 4 parts, stabilizer polyethylene glycol 800 2 parts, plant fragrance dandelion extract 0.8 parts, surfactant lauryl polyether sulfate ammonium 2 parts, alcohol 8 parts, and the rest is deionized water. The preparation process is as follows: guanidine nitrate and C3N4 composite nanoparticles are added to water and ultrasonicated for 50 minutes to obtain a dispersed mixture. Then, the surfactant, stabilizer, plant fragrance and alcohol are added in sequence, and the mixture is stirred for another 4 hours to obtain a visible light catalytic disinfectant for emergency room application.

[0046] The dandelion extract is prepared by adding 30 parts by mass of water to 1 part by mass of the plant at pH = 3, heating to 55°C and soaking for 30 hours, then filtering and extracting twice with 20 parts by mass of petroleum ether. The extract is concentrated by rotary evaporation to obtain a transparent oil plant fragrance.

[0047] Guanidine nitrate and C3N4 composite nanoparticles are prepared according to the principle shown in FIG. 2. Figure 1 ​As shown, by the following steps: urea was pyrolyzed in nitrogen at 590°C for 4h with a heating rate of 3°C / min, obtaining yellowish C3N4 with a yield of 34%; C3N4 was added into acetonitrile solvent, and ultrasonic stripping was performed at a power of 60 kHz for 5h, and after standing for 7h, the upper layer of white milky turbid liquid was taken, 1.4 parts by mass of n-propyl isocyanate and 0.4 parts by mass of triethylamine were mixed, and the mixture was heated to reflux for 32h, and then filtered to obtain white particles, which were dried at 60°C under vacuum for 20h;

[0048] 1.2 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent were added, and grinding was performed at room temperature for 55min, and after the solvent was volatilized, heating was continued to 170°C under nitrogen for 4h, and then dried at 60°C under vacuum for 18h, and the rest of the process was the same as that described in Example 1, obtaining guanidine nitrate C3N4.

[0049] The sample obtained in Example 2 and pure C3N4 were characterized by TG-DTG, and the results are shown in Figure 3

[0050] In the figure: the left is the TG thermogravimetric analysis diagram, and the right is the DTG differential thermal analysis diagram, 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 weight loss curve of the guanidine nitrate C3N4 composite photocatalyst is significantly different from that of C3N4, which is one of the evidences for the successful preparation of the former.

[0051] Example 3: A visible light catalytic disinfectant for aerosol attached pathogenic bacteria in an emergency room, which includes guanidine nitrate and C3N4 composite nanoparticles, plant fragrance, stabilizer, surfactant lauryl alcohol polyether sulfate ammonium, water and alcohol; the components are 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 lauryl alcohol polyether sulfate ammonium, 4 parts of alcohol, and the rest is deionized water, all by mass fraction. The preparation process is as follows: take guanidine nitrate and C3N4 composite nanoparticles, add water and ultrasonic for 40 min to obtain a dispersed mixture, then add surfactant, stabilizer, plant fragrance and alcohol in turn, and continue to stir for 4h, to obtain a visible light photocatalytic disinfectant for emergency room application.

[0052] The preparation steps of wild chrysanthemum extract are as follows: add 40 parts by mass of water to 1 part by mass of plant, pH=2.5, heat to 50°C and soak for 32h, then filter, and extract twice with 25 parts by mass of petroleum ether, and then concentrate the extract liquid by rotary evaporation to obtain a transparent oil plant fragrance.

[0053] ​The composite nanoparticles of guanidine nitrate and C3N4 are prepared by the following steps: urea is placed in nitrogen, pyrolysis calcination at 590°C for 4h, the heating rate is 4°C / min, yellowish C3N4 is obtained, the yield is 33%; C3N4 acetonitrile solvent is ultrasonically exfoliated in 40kHz power for 5h, the upper layer white milky turbid liquid is taken after standing for 6h, 1.3 parts by mass of tert-butyl isocyanate and 0.3 parts by mass of triethylamine are mixed, heating reflux reaction is carried out for 28h, white particles are obtained by filtration, vacuum drying is carried out for 18h; 1.2 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent are added to the white particles in a nitrogen-filled glove box, grinding is carried out at room temperature for 60min, after the volatile solvent is dried, heating to 160°C is continued under nitrogen protection for 4h, washing and filtering are carried out with 20 parts by mass of water and ethanol, vacuum drying is carried out at 60°C for 20h, and the rest is the same as the method described in Example 1, to obtain guanidine nitrate C3N4.

[0054] Example 4: A visible light catalytic disinfectant for aerosol attached pathogenic bacteria in an emergency room, which raw materials include composite nanoparticles of guanidine nitrate and C3N4, honeysuckle extract, stabilizer polyethylene glycol 800, surfactant lauryl polyoxyethylene sulfate ammonium, water and alcohol; the components are 1 part of guanidine nitrate C3N4 composite nanoparticles, 1 part of stabilizer, 0.5 parts of plant fragrance, 1 part of surfactant, 1 part of alcohol, and the rest is deionized water, with 100 mass fractions. The preparation process is as follows: take the composite nanoparticles of guanidine nitrate and C3N4, add water to ultrasonic for 30 min to obtain a dispersed mixture, then add the surfactant, stabilizer, plant fragrance and alcohol in turn, continue to stir for 3h, and the visible light catalytic disinfectant for aerosol attached pathogenic bacteria in an emergency room is obtained.

[0055] The honeysuckle extract preparation steps are as follows: 1 part by mass of plant is added to 50 parts by mass of water, pH=2.5, heated to 65°C and soaked for 36h, then filtered, and extracted twice with 30 parts by mass of petroleum ether, the extract is concentrated by rotary evaporation, and a transparent oil plant fragrance is obtained.

[0056] The composite nanoparticles of guanidine nitrate and C3N4 are prepared by the following steps: urea is placed in nitrogen, pyrolysis calcination at 600℃ for 5h, the heating rate is 5℃ / min, a yellowish C3N4 is obtained with a yield of 30%; C3N4 is added into acetonitrile solvent, ultrasonic stripping at 40kHz power for 4h, the upper layer white milky turbid liquid is taken after standing for 6h, mixed with 1.2 parts by mass of isopropyl isocyanate and 0.2 parts by mass of triethylamine, heated to reflux for 24h, filtered to obtain white particles, vacuum dried at 60℃ for 16h; the white particles are added with 1.3 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent, ground at room temperature in a nitrogen-filled glove box for 60min, after the volatile solvent is dried, continue to heat to 180℃ under nitrogen protection for 5h, washed with 20 parts by mass of water and ethanol, filtered and vacuum dried at 60℃ for 24h, and the rest is the same as the method described in Example 1, to obtain guanidine nitrate C3N4.

[0057] The sample obtained in Example 4 and pure C3N4 are characterized by SEM electron microscope, and the results are shown in Figure 4 .

[0058] In the figure: the electron microscope photo of the guanidine nitrate C3N4 composite photocatalyst (right) is similar to that of C3N4 (left), proving that the introduction of guanidine nitrate does not change the morphological characteristics of C3N4.

[0059] Corresponding to the above four examples, four application examples are given.

[0060] Application Example 1: On February 1, random ward sampling was carried out in the emergency ward (the patient left at least one day for routine disinfection and ultraviolet sterilization), liquid impact type microbial aerosol sampler was used to sample indoor aerosol particles, indoor aerosol particles were collected, and the test results are shown in Table 1, and the sample was placed in a refrigerator for standby. Quantitatively take a small amount of sample and culture on a culture dish, beef extract protein peptone agar medium. At least three groups of parallel experiments (3-5 culture dishes per group) are set, divided into a control group (without catalyst), a dark experiment group (sprayed with the photocatalytic disinfectant described in Example 1 without light), and a light experiment group (sprayed with the photocatalytic disinfectant described in Example 1 with light). Move to a constant-temperature microbial incubator for culture at 37℃, and observe and record at 24h and 48h, respectively, scrape the sample with a sterilized spoon at the most vigorous period of bacterial production, and store it in dry ice at -20℃, analyze the change of microbial species by bacterial 16s V3V4 high-throughput analysis, and the test results are shown in Figure 6 .

[0061] Figure 6 The microbial species level column chart of the sample obtained in Example 1 (CK is the control group, and sample 1 is tested twice in parallel).

[0062] In the figure: the 20 microorganism species with the highest detection levels in the control group include MBNT15 (a kind of desulfurization bacillus), Romboutsia (Romboutsia), Pseudogracilibacillus (Pseudogracilibacillus), 0319−6G20 (a kind of unknown Proteobacteria), Subgroup_10 (unknown subgroup), Ellin6067 (a kind of unknown Proteobacteria), Sporosarcina (Sporosarcina), Helicobacter (Helicobacter pylori), Pseudomonas (Pseudomonas aeruginosa), Rhodococcus (Rhodococcus), Comamonas (Comamonas), Noviherbaspirillum (Noviherbaspirillum), Pantoea (Pantoea), Cupriavidus (Cupriavidus), Lactobacillus (Lactobacillus), Sphingomonas (Sphingomonas), Allorhizobium−Neorhizobium−Pararhizobium−Rhizobium (a kind of Rhizobium), Bacillus (Bacillus), Herbaspirillum (Herbaspirillum), Burkholderia−Caballeronia−Paraburkholderia (Burkholderia−Caballeronia−Paraburkholderia), most of these bacteria belong to the living space of patients with intestinal diseases, reproductive system infections, immune system infections, and pulmonary infectious diseases. However, after the composite photocatalyst disinfection, the diversity of microorganism species attached to aerosol particles decreased significantly, and the harmful bacteria that dominated in the control group were all weakened or even disappeared, and instead, Burkholderia occupied the dominant position. This genus mostly appears 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), promotes plant growth, biological nitrogen fixation, secretes antibiotics, prevents pests and diseases, and is used for microbial synthesis of chemicals or degradation of aromatic hydrocarbon pollutants (Patent Publication No. CN 117757690 A; Publication No. CN 116024136 A; Authorized No. 202410443471.3).

[0063] Example 2: On May, random room sampling in emergency room (patients left at least one day, to carry out routine disinfection and ultraviolet sterilization), the liquid impact type microbial aerosol sampler was used to sample the indoor aerosol particles, and the indoor aerosol particles were collected. The test results are shown in Table 1, and the samples were placed in the refrigerator for standby. Quantitative micro-samples were cultured on petri dishes with beef extract peptone agar medium. At least three sets of parallel experiments were set up (3-5 petri dishes per group), divided into control group (no catalyst), dark experiment group (spray photocatalystic disinfectant described in Example 2, no light), light experiment group (spray photocatalystic disinfectant described in Example 2, with light). Move to the constant temperature microbial incubator for incubation at 37°C, and observe and record at 24h and 48h respectively. At the most vigorous period of bacterial production, samples were scraped with a sterilized spoon and stored at -20°C dry ice. The change of microbial species was analyzed by bacterial 16s V3V4 diversity high-throughput analysis. Figure 5

[0064] Figure 5 The petri dishes of the control group (left), guanidine nitrate C3N4 (middle, dark), and guanidine nitrate C3N4 (right, light).

[0065] In the figure: the control group (left) petri dish without catalyst found white bacteria of different sizes, while adding guanidine nitrate C3N4 (middle) without light, it can show inhibition to white bacteria, and grow into light green bacteria band. Finally, in the guanidine nitrate C3N4 (right) petri dish with light, more significant light green bacteria band can be seen. This experiment can directly 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 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 subsequent microbial diversity.

[0066] Example 3: On August, random room sampling in emergency room (patients left at least one day, to carry out routine disinfection and ultraviolet sterilization), the liquid impact type microbial aerosol sampler was used to sample the indoor aerosol particles, and the indoor aerosol particles were collected. The test results are shown in Table 1, and the samples were placed in the refrigerator for standby. Quantitative micro-samples were cultured on petri dishes with beef extract peptone agar medium. At least three sets of parallel experiments were set up (3-5 petri dishes per group), divided into control group (no catalyst), dark experiment group (spray photocatalystic disinfectant described in Example 3, no light), light experiment group (spray photocatalystic disinfectant described in Example 3, with light). Move to the constant temperature microbial incubator for incubation at 37°C, and observe and record at 24h and 48h respectively. At the most vigorous period of bacterial production, samples were scraped with a sterilized spoon and stored at -20°C dry ice. The change of microbial species was analyzed by bacterial 16s V3V4 diversity high-throughput analysis, and the test results are shown in​Figure 7 .

[0067] Figure 7 The species level histogram of the sample obtained in Example 3 (CK is the control group, sample 3 is tested twice in parallel).

[0068] In the figure: the top 20 microorganism species detected in the control group include Dechloromonas, Cetobacterium, Faecalibacterium, Citrobacter, RBG−16−58−14 (a kind of chlorobacterium), Escherichia−Shigella, Serratia, Candidatus_Amoebophilus, Limosilactobacillus, Exiguobacterium, 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, wound infections, and pulmonary infectious diseases. However, after the composite photocatalyst is used for sterilization and killing, the diversity of microorganism species attached to the aerosol particulate matter is significantly reduced, the harmful bacteria that dominate in the control group are all weakened or even disappear, and instead, Burkholderia dominates.

[0069] Application Example 4: On November, random ward sampling was carried out in the emergency ward (patients left at least one day for routine disinfection and ultraviolet sterilization), liquid impact microbial aerosol sampler was used to sample indoor aerosol particles, indoor aerosol particles were collected, and the test results are shown in Table 1, and the samples were placed in the refrigerator for standby. Quantitatively take a small amount of sample and culture on a petri dish, beef extract protein peptone agar medium. At least three groups of parallel experiments (3-5 petri dishes per group) were set up, divided into control group (no catalyst), dark experiment group (spray photocatalyst described in Example 4, no light), light experiment group (spray photocatalyst described in Example 4, with light). Move to the constant temperature microbial incubator for culture at 37℃, and observe and record at 24h and 48h respectively, and use a sterilized spoon to scrape the sample at the most vigorous period of bacterial production, and store it in -20℃ dry ice. The change of microbial species was analyzed by bacterial 16s V3V4 diversity high-throughput analysis.

[0070] The diversity test results of application examples 1-4 are collected, as shown in Figure 8

[0071] In the figure: 1-4 are the samples taken in February, May, August and November of the same year (application examples 1-4). The species diversity index of indoor aerosol particle attached microorganisms of nitric acid guanidine C3N4 composite photocatalyst (light and dark groups) is significantly lower than that of the control group, indicating that the guanidine group on the surface of nitric acid guanidine C3N4 composite photocatalyst has certain bacteriostatic performance in dark environment, and the surface charge is beneficial to the contact of catalyst with bacterial wall, which destroys the metabolic function of enzymes in cell membrane. However, the composite photocatalyst performs better after light, which proves that the photo-generated electrons and holes on the surface of the catalyst continue to affect the bacterial wall, and the photo-generated free radicals can also participate in the inhibition of the metabolic function of microorganisms.

[0072] Combined with Figure 5 analysis, the bacterial growth of the control group is not as good as that of the experimental group, but its species diversity is higher; the bacterial growth of the experimental group is better than that of the control group, but its species diversity decreases significantly. After adding photocatalyst, it is indeed that the reproduction of harmful microorganisms is inhibited, especially under light conditions, which leads to the change of dynamic balance of microorganisms in the petri dish, and the reproduction of beneficial bacteria such as Burkholderia will compress the living space of harmful microorganisms. It can also be considered that the growth of harmful microorganisms is limited, which stimulates the reproduction of the rest of the bacteria such as Burkholderia.

[0073] ​Emergency room indoor aerosol particles were collected for culture and then microorganism species diversity analysis: aerosol particles collected in the emergency room were cultured. Beef extract protein peptone agar medium formula (reference Microbial Pharmaceutical Technology (Wu Xiuling, Li Gongbin, China Light Industry Press, 2025) beef extract 3.0 g, protein peptone 10.0 g, sodium chloride 5.0 g, agar 15-25 g, water 1000 ml, pH: 7.4-7.6.

[0074] Specific process: 30 mL of culture medium was introduced into each culture dish, 100 μL of aerosol particles was added for inoculation, and 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 LED light with a power of 75 W, color temperature of 6000-9000 K, light efficiency of 93 Lm / W, and lamp source diameter of 90 mm for 2-3 h, and then transferred to a constant temperature microbial incubator for culture at 37°C. Observation and recording were performed at 24 h and 48 h, respectively. The microorganisms cultured on the plates were collected, and a sterile spoon was used to scrape them at the most vigorous growth period, and then placed in a 1.5 or 2.0 ml centrifuge tube. The centrifuge tube was quickly placed in liquid nitrogen for freezing for about 10 min, and then transferred to dry ice at -20°C for storage. The change in microbial species was analyzed by bacterial 16s V3V4 diversity high-throughput analysis. The results of aerosol particles collected in the emergency room are shown in Table 1.

[0075] Table 1 Test results of aerosol particles collected in four seasons

[0076]

[0077] According to [Particle and Microbial Aerosol Sampling and Analysis (GB / T 38517-2020)], a liquid impact type microbial aerosol sampler was used to sample and analyze indoor aerosol particles. The test height was 1 m, the sampling time was 120 min, the flow rate was 8.5 L / min, and the collection medium was sterile ultrapure water filtered by microfiltration membrane. 1-4 were the samples collected in February, May, August, and November of the same year, respectively, and 0 was the background value of the clean space outside the hospital ward. As can be seen from the table, although the emergency room has been routinely disinfected and sterilized by ultraviolet light, there are still a considerable number of aerosol particles remaining in the room. These aerosol particles provide a carrier for the attachment of pathogenic microorganisms and viruses, and the organic pollutants on the particles even provide certain nutrients for the survival of bacteria, objectively causing a high risk of transmission of epidemic bacteria and viruses in a confined space.

[0078] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A visible light catalytic disinfectant against aerosol attached pathogenic bacteria in an emergency room, characterized by: The disinfectant comprises composite nanoparticles of guanidine nitrate C3N4 and deionized water; The composite nanoparticles of guanidine nitrate C3N4 are prepared by the following method: (1) Urea is placed in nitrogen, and pyrolysis calcination is performed at a temperature increasing rate of 2-5 ℃ / min to 580-600 ℃ for 3-5 h to obtain yellowish C3N4 with a yield of 30%-35%; (2) 100 parts by mass of acetonitrile solvent is added to 1 part by mass of C3N4, ultrasonic stripping is performed at a power of 40-80 kHz for 4-6 h, and after standing for 6-8 h, the upper layer of white milky turbid liquid is taken, 1.2-1.5 parts by mass of isocyanate and 0.2-0.5 parts by mass of triethylamine are added, and reflux reaction is performed for 24-36 h to obtain white particles, which are vacuum dried at 60 ℃ for 16-24 h; (3) 1 part by mass of the white particles obtained in step (2) is added to 1.0-1.3 parts by mass of ammonium nitrate and 5 parts by mass of ethanol solvent, and grinding is performed at room temperature in a nitrogen-filled glove box for 50-60 min, and after the solvent is volatilized and dried, heat treatment is performed at 150-180 ℃ for 3-5 h under nitrogen protection, and then the product is washed with 20 parts by mass of water and ethanol, filtered, and vacuum dried at 60 ℃ for 16-24 h to obtain guanidine nitrate C3N4.

2. The visible light catalytic disinfectant for aerosol attachment pathogenic bacteria in emergency room according to claim 1, characterized in that: The isocyanate in step (2) comprises any one of tert-butyl isocyanate, isopropyl isocyanate, ethyl isocyanate, n-propyl isocyanate, and n-butyl isocyanate.

3. The visible light catalytic disinfectant for aerosol attachment pathogenic bacteria in emergency room according to claim 2, characterized in that: The isocyanate in step (2) is isopropyl isocyanate.

4. The visible light photocatalytic disinfectant against aerosol attached pathogenic bacteria in an emergency room according to claim 1, characterized by: The disinfectant further comprises a plant fragrance, a stabilizer, a surfactant, and alcohol.

5. The visible light catalytic disinfectant against aerosol attached pathogenic bacteria in an emergency room according to claim 4, characterized in that: The disinfectant is prepared from the following raw materials in the weight parts indicated in 100 parts by mass: 1-5 parts of the composite nanoparticles of guanidine nitrate C3N4, 0.5-1 part of a plant fragrance, 1-3 parts of a stabilizer, 1-3 parts of a surfactant, 1-10 parts of alcohol, and the rest is deionized water.

6. The visible light catalytic disinfectant against aerosol attached pathogenic bacteria in an emergency room according to claim 5, characterized in that: The stabilizer is polyethylene glycol 800. The plant fragrance is an extract of a herbaceous plant having antibacterial efficacy; the specific extraction method is as follows: 25-50 parts by mass of water is added to 1 part by mass of the herbaceous plant, the pH is adjusted to 2.5-3.5, and then the mixture is heated to 45-65 ℃ for 24-36 h of decoction, and then filtered, and the extract is extracted twice with 15-30 parts by mass of petroleum ether, and then the extract liquid is concentrated by rotary evaporation to obtain a transparent oily plant fragrance. The surfactant is ammonium lauryl polyether sulfate.

7. The visible light photocatalytic disinfectant against aerosol attached pathogenic bacteria in an emergency room according to claim 6, characterized by: The plant fragrance is an extract of any one or any combination of mint, dandelion, wild chrysanthemum, and honeysuckle.

8. A method of preparing the visible light catalytic disinfectant against aerosol attached pathogenic bacteria in an emergency room according to claim 4, characterized by: The composite nanoparticles of guanidine nitrate C3N4 are ultrasonically dispersed in water for 30-60 min to obtain a dispersion mixture, and then a surfactant, a stabilizer, a plant fragrance, and alcohol are sequentially added, and stirring is continued for 3-5 h to obtain a visible light catalytic disinfectant for aerosol attached pathogenic bacteria in an emergency room.

9. Use of the visible light catalytic disinfectant for aerosol attached pathogenic bacteria in an emergency room according to any one of claims 1-7 as a disinfectant spray for inhibiting aerosol attached pathogenic bacteria in indoor air.

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