RU2743705C1 - Method for air photocatalytic purification and sterilization - Google Patents

Abstract

FIELD: medical equipment.SUBSTANCE: invention relates to multipurpose medical equipment. Disclosed is a method of air photocatalytic purification and sterilization. The method includes passing air through a photocatalytic membrane. A porous copper-based carrier is used as a photocatalytic membrane. The porous copper-based carrier includes microporous copper or bronze 3 mm thick with pore sizes from 0.5 to 20 mcm. Likewise, a porous carrier with a microporous structure with a coating of the pore surface made of copper nanoparticles can be used as a photocatalytic membrane. The photocatalytic membrane is continuously irradiated with a visible light source, which is an LED matrix, in the spectral range from 400 to 780 nm with luminous power density of 250-500 mW/cm2. The flow rate of the purified air through the photocatalytic membrane is maintained in the range from 1 to 5 m/s.EFFECT: invention can be used in the processes of air purification and sterilization primarily in medical premises including operating rooms, dental offices, maternity wards as well as in residential and industrial premises and in road, rail, water and air transport.1 cl, 4 ex, 4 tbl, 1 dwg

Description

The invention relates to medical equipment for general purposes and can be used in the processes of purification and sterilization of air, primarily in medical premises, including operating rooms, dental offices, maternity wards, and so on, as well as in residential and industrial premises, on road, rail, water and air transport.

For certain premises, there are requirements for the need for air disinfection and equipping them with bactericidal installations [Р3.5.1904-04. Leadership. Disinfectology. Use of ultraviolet bactericidal radiation for indoor air disinfection. - M., 2005.]. The most important objects from this point of view are hospital institutions in which the need for air disinfection is strictly regulated [SanPiN 2.1.3.1375-2003. Hygienic requirements for the placement, arrangement, equipment and operation of hospitals, maternity hospitals and other medical hospitals], as well as medical institutions [Borisoglebskaya A.P. Treatment-and-prophylactic institutions. General requirements for the design of heating, ventilation and air conditioning systems. - M .: "AVOK-PRESS", 2008.].

However, in the case of epidemics and pandemics of viral infections transmitted by airborne droplets and caused by the emergence of new virus strains as a result of mutation, the problem of air disinfection in household and public premises, including air volumes inside vehicles, stations, terminals, airports, arises. ... The most significant in terms of the number of victims over the past hundred years was the pandemic of the coronavirus infection COVID-19, the Hong Kong flu (in three years (1968-1970) from one to four million people died from it [Rogers, Kara. Hong Kong flu of 1968. Encyclopaedia Britannica . Open Publishing]) and the Spanish flu, which killed approximately 50 million people between 1918-1920 [Rewar S, Mirdha D, Rewar P. Treatment and Prevention of Pandemic H1N1 Influenza // Ann Glob Health. 2015; 81 (5): 645-53 doi.org/10.1016/j.aogh.2015.08.014].

It is known that non-disinfected air, as well as ventilation and air conditioning systems, can be sources of infection for humans and animals with pathogens such as viruses, bacteria, protozoa and fungi. Infectious agents settle in ventilation, cleaning and air conditioning systems and multiply on their storage plates and filters. In particular, one of the most dangerous man-made infections is legionellosis [Zueva LP, Yafaev R.Kh. Chapter 21. General characteristics of sapronosis // Epidemiology. - SPb .: Foliant, 2005. - S. 556. - 752 s].

In this regard, in the Resolution No. 4 of August 27, 2004, issued by the Ministry of Health of Russia, "On the organization and implementation of cleaning and disinfection of ventilation and air conditioning systems", the main provision is the requirement to equip ventilation and air conditioning systems with bactericidal equipment based on modern technologies.

Recently, it has been proposed to use strong electric fields for air disinfection, in which destruction or electroporation of microorganisms occurs.

A known method of air purification in ventilation and air conditioning systems using filtration, including using HEPA filters [US Patent 6428610 B1, Hepafilter, 02.08.2002]. The method consists in the fact that the filters are impregnated with a special dust-binding liquid, which allows you to retain up to 90-95% of microbes and dust particles contained in the air. Despite the high efficiency of retention of microorganisms, this method cannot provide the sterilization of air necessary for certain classes of premises, taking into account the requirements contained in the above documents.

An additional disadvantage of the known method is the low efficiency of air sterilization from pathogens less than 0.3 microns in size due to the fact that the filter material of the HEPA filter is not able to retain them. Also, the disadvantage is the need to timely replace the filter with a new one in order to exclude the subsequent contamination of the purified air by pathogens deposited on the filter, since this method does not imply their inactivation.

One of the most widely used methods of purification and sterilization of air is a method based on the use of the oxidizing properties of a photocatalytic element based on titanium dioxide, a non-toxic, chemically stable compound [YaronPaz, Application of TiO2 photocatalysis for air treatment: Patent's overview, Applied Catalysis B, vol. 99, pp. 448-460, 2010].

The photocatalytic properties of titanium dioxide have been known for a long time. Research in this area has been carried out since 1930 [Journal of Engineering (IOSRJEN): 2250-3021 V.2, N.8, 2012, p.50-53 The progress of TiO2 photocatalyst coating]. Work on the purification of industrial gases from chemical impurities by their oxidation using titanium dioxide irradiated with UV radiation at a wavelength of about 350 nm has become widespread [RF Patent 2450851, Method for cleaning and disinfecting air, 27.08.2011], [Patent EP 0987048 A1, 22.05 .2000 Method of purification from organic compounds].

Recently, work related to the use of titanium dioxide as an oxidizing agent is mainly focused on improving its oxidizing properties. For example, there is a known method for increasing the efficiency of the oxidizing properties of titanium dioxide [US Patent 20130129805 A1, dated 05/23/2013], which uses titanium dioxide in combination with metallic silver, which is an additional oxidizing agent. Also, there is a known oxidation method [RF Patent 2259866, Method for photocatalytic gas cleaning, 09/10/2005], in which the cleaned air is additionally saturated with hydrogen peroxide vapor.

There is a known method of air purification from organic impurities / RF Patent N 2071816, B 01 D 53/72, 53/86, 1997 /, which consists in the fact that air with impurities of organic compounds is passed first through the zone of a pulsed gas discharge, and then through a photocatalyst unit that is illuminated with a light source in visible or ultraviolet radiation. In this case, the photocatalyst unit may contain tubular glass elements on which a layer of catalyst-titanium dioxide powder is applied.

The method is rather difficult to use, has insufficiently high efficiency due to the small surface area of the catalyst.

The closest in technical essence is a method of air purification using photocatalytic membrane filters using titanium dioxide [RF Patent No. 2151632, Photocatalytic element and method for its production, 06/27/2000]. The known method is carried out by creating a photocatalytic element based on a porous carrier coated with titanium dioxide. This photocatalytic element actively destroys organic impurities in the gas, but does not provide for the production of sterilized air, which is a significant disadvantage of the known method.

A photocatalytic element for air purification from organic impurities, containing a porous carrier and anatase modification titanium dioxide powder applied to the carrier surface, is made in a predetermined design form of at least five layers of sintered glass beads with a diameter of at least 0.1 mm, and titanium dioxide used with a specific surface of 100 - 150 m ² / g and a mesopore size of 5-15 nm.

A serious disadvantage of using photocatalytic filters with titanium dioxide in the known methods is the use of UV radiation for irradiation of titanium dioxide. This disadvantage limits the use of such oxidizing devices in rooms with people. The use of radiation in the visible region of the spectrum could eliminate this problem, however, it is known that this dramatically decreases the efficiency of the photocatalytic element based on titanium dioxide.

An additional disadvantage is also the insufficient strength of the titanium dioxide coating, which in some cases leads to shedding of titanium dioxide nanoparticles from the support.

A technical problem is the development of a method for effective contact and photocatalytic inactivation of pathogens, including any enveloped viruses, for example, influenza viruses and coronaviruses, in purified air passed through a photocatalytic membrane illuminated by visible light.

The technical result from the use of the developed method is to increase its efficiency by ensuring the complete inactivation of the influenza virus in the air.

In addition, an increase in the structural strength of the photocatalytic element and a reduction in harm from ultraviolet radiation are provided.

The technical problem is solved and the technical result is achieved by the fact that the method of photocatalytic purification and sterilization of air, including its passage through a photocatalytic membrane, consists in the fact that a porous carrier based on copper is used as a photocatalytic membrane, for example, microporous copper or bronze with a thickness of up to 3 mm with pore sizes from 0.5 to 20 microns, or a porous carrier with a microporous structure and coating of the pore surface with copper nanoparticles, with continuous irradiation of the photocatalytic membrane with a visible light source, for example, an LED matrix in the spectral range from 400 to 780 nm with a luminous flux power density of 250-500 mW / cm ² , while the flow rate of the purified air through the photocatalytic membrane is maintained in the range of 1-5 m / s.

A porous carrier made of copper or a copper-containing alloy (bronze) is used as a photocatalytic membrane, for example, made by hot pressing, JSC "Uralelectromed" according to TU 1990-122-00194429-2015.

The structural strength of copper and its alloys is ensured by its metallic nature. The strength of the coating based on copper nanoparticles is ensured by special methods of applying these coatings.

For example, the deposition of a coating of copper nanoparticles on the surface of the pores of a microporous permeable ceramic membrane made of corundum with a thickness of 3 mm and an average pore size of 0.5 to 20 μm was carried out as follows.

The necessary solution for the chemical deposition of copper nanoparticles on the surface of the membrane pores was prepared as follows. In a glass containing 150 ml of distilled water, 10 ml of hydrazine monohydrate was added to provide an oxygen-free environment, 0.32 g of copper sulfate pentahydrate (based on anhydrous copper sulfate), 18.8 g of ascorbic acid (reducing agent), concentrated ammonia solution to pH 8.5-9.0 , and 2.5 g of polyethylene glycol. Polyethylene glycol has been used as a surfactant. The resulting mixture was stirred on a magnetic stirrer for 2 minutes at room temperature to obtain a homogeneous solution.

The membrane, previously defatted with acetone and alcohol, treated with distilled water and dried in air, was placed in the prepared liquid mixture. The composition was allowed to stand for 10 minutes to effectively impregnate the entire volume of the porous structure with the solution. Then the glass was placed in a heating furnace and kept at a temperature of 90 ° С for 5.0 min. In this case, the reaction of copper reduction to copper nanoparticles under the action of ascorbic acid in a weakly alkaline medium in the porous structure of the membrane occurred. The formed copper nanoparticles, possessing high surface energy due to their nanosize, are easily sorbed by the developed porous membrane surface. Then the membrane was removed from the solution, thoroughly washed with distilled water, and dried at room temperature.

Membrane thickness and pore sizes are selected based on the need to meet the following requirements:

The pore sizes of the microporous membrane used in the invention are 0.5 - 20 μm and are chosen to ensure a sufficiently complete penetration into the porous structure of the membrane of most pathogenic organisms present in the air, such as influenza virus or coronavirus with an average size of 0.1 μm, as well as such pathogenic bacteria, such as staphylococci - about or slightly more than 10 microns in size. The high branching of the microporous structure of the membrane in combination with its sufficient thickness guarantees high efficiency of the photocatalytic and contact activity of copper during air sterilization. It should be noted that such a membrane also has a fairly high gas permeability. According to the proposed method, the range of flow rates of the inactivated air is from 1 to 5 m / s. In this case, complete inactivation of the air is noted.

An increase in the efficiency of using the photodynamic properties of the copper surface of a porous membrane in the process of inactivation of pathogens in the purified air is also facilitated by the fact that a microporous membrane 3 mm thick is illuminated by light from an LED source rather effectively in its entire volume, since the high reflectivity of the copper surface (on average 60 -70%) promotes deep penetration of light into the volume of the porous membrane in the process of multiple reflections of the radiation of LED matrices from the surface of the pores.

The unique photophysical properties of copper, in particular, the high "contact killing" of bacteria and viruses by copper, attracted wide attention of researchers to the study of various properties of copper as an antibacterial, antifungal and antiviral agent [Contact killing and antimicrobial properties of copper. M. Vincent, et all. Journal of Applied Microbiology 124, 1032-1046 © 2017; Debirupa Mitra et all. Antimicrobial Copper-Based Materials and Coatings: Potential Multifaceted Biomedical Applications. ACS Appl. Mater. Interfaces. 2019. DOI: 10.1021 / acsami.9b17815].

Mechanisms of the antibacterial, antifungal and antiviral action of copper: contact, photocatalytic and thermal.

It is known that bacteria, yeast and viruses quickly die on copper surfaces; for this process, the term "contact killing" was even coined. Although this phenomenon has been known since ancient times, there is now renewed interest in it due to the potential use of copper as an antibacterial material in medical settings.

It has been shown that noroviruses are destroyed on surfaces made of copper alloys [Warnes S.L., Keevil C.W. Inactivation of Norovirus on Dry Copper Alloy Surfaces // PLOS One. 2013. Vol. 8. Issue 9. P. e75017]. As for the human coronavirus 229E, it was also rapidly inactivated on a number of copper alloys (within a few minutes) [Warnes S.L., Little Z.R., Keevil C.W. Human Coronavirus 229E Remains Infectious on Common Touch Surface Materials // mBio. 2015. Vol. 6. Issue 6. P. e01697-15], and the Cu / Zn alloy was very effective at lower copper concentrations. Exposure to copper destroyed viral genomes and irreversibly affected the morphology of the virus. Cu (I) and Cu (II) were responsible for the inactivation of pathogens, which was enhanced by the formation of reactive oxygen species on the alloy surfaces. This indicates a fairly high photocatalytic activity of copper. Consequently, copper alloy surfaces can be used in public places and at any mass gathering to help reduce transmission of respiratory viruses from contaminated surfaces and protect public health.

As a source of radiation for copper-based carriers, LED radiation sources are used, mainly LED matrices, emitting in the visible region of the spectrum from 400 to 780 nm and operating in a continuous mode. In this case, the copper-based carrier is simultaneously irradiated with LEDs and the purified air is passed through the carrier.

The advantage of the proposed method of photocatalytic purification and sterilization of air relative to the closest technical solution is a higher efficiency of sterilization and air purification by passing the purified air through a volumetric photocatalytic element illuminated by visible light (instead of ultraviolet) in the form of a porous structure based on copper, providing contact and photocatalytic destruction of viruses at the entire depth of the porous structure, in contrast to thin film coatings, and also having higher strength and photostable properties.

The method of photocatalytic purification and sterilization of air is implemented using a device in which a photocatalytic membrane based on copper with a thickness of up to 3 mm with pore sizes from 0.5 to 20 μm is used.

An example of the implementation of the method using a device for air disinfection based on a microporous carrier based on copper (Fig. 1).

The diagram of the device is shown in Figure 1, where 1 is an input filter, 2 is a radiator for cooling LED matrices, 3 are LED matrices, 4 is a photocatalytic membrane, 5 is a fan, 6 is a power supply unit for LED matrices.

The device works as follows:

The air is sucked into the intake device by a fan, filtered on the inlet filter 1 from dust and moisture, passes through the holes in the radiator 2, which cools the LED matrices 3, and enters the surface of the photocatalytic membrane illuminated with white light by LED matrices ARPL-100W-EPA-5060.

LEDs provide during operation continuous illumination of a photocatalytic membrane based on a microporous copper or bronze membrane with white light with a power density of 250-500 mW / cm ² .

Pathogens contained in the purified air are retained on the microporous membrane and are inactivated by contact with copper “contact kill” and with reactive oxygen species generated on the membrane surface when it is irradiated with LEDs. The air purified by a microporous membrane passes further through the fan and enters the room.

1. An example of contact inactivation of viruses (performed at the Pasteur Institute in May 2020) on a photocatalytic membrane based on porous bronze in a stationary air environment.

Samples . Microporous bronze plates (plate dimensions 30x40 mm, thickness 3 mm, pore sizes from 0.5 to 20 μm) were used as a photocatalytic membrane in the tests.

Viruses. The process of inactivation of viruses is considered on the example of the influenza A / Puerto Rico / 8/34 (H1N1) virus from the collection of viral strains of the Research Institute of Influenza of the Russian Academy of Medical Sciences. The virus was cultured for 48 hours at 36 ° C in the allantoic cavity of 10-12 day old chicken embryos.

Preparation of infectious material .

To prepare samples for testing, an allantoic fluid containing influenza virus in a volume of 0.3 ml at a dose of 5 × 10 ⁵ TCID ₅₀ / ml was applied to the surface of the studied materials. The virus was evenly distributed over the surface of the material, dried and irradiated under appropriate conditions. The control sample was not irradiated.

Equipment preparation.

A chamber with a volume of 0.4 m ^{3 was} used as a box. The porous bronze sample was illuminated in the visible spectral range from 400 to 780 nm using an ARPL-100W-EPA-5060 LED matrix with an emitting surface of 26x26 mm and an angular radiation divergence of 110 degrees.

Procedure and results of photocatalytic contact inactivation of viruses ...

The samples were placed in turn in a box and fixed at an appropriate distance from the radiation source (15 mm or 30 mm) parallel to the plane of the LED array. The light power density on the porous bronze sample was 500 and 250 mW / cm ² , respectively. The irradiation was carried out for 30 minutes. A similar sample of microporous bronze, not exposed to irradiation and kept in the box for 30 minutes, served as a control. Forced convection of air in the chamber was not carried out.

After 30 minutes, each of the samples was taken out of the box, the virus was washed off the surface with three portions of saline, 0.5 ml each, and the infectious activity of the virus was determined in the washings by titration in MDCK cells. The titration results are shown in Table 1.

Table 1

Sample Infectious
virus titer (TCID ₅₀ / ml) Microporous bronze (distance to source 15 mm) 0.0 Microporous bronze (distance to the source 30 mm); 0.0 Microporous bronze (no irradiation) 5 × 10 ³ The initial titer of the virus in the infectious material 5 × 10 ⁵

As can be seen from the above data, the procedure of drying the virus, followed by a half-hour exposure to air and further washing off the bronze surface, led to a decrease in the infectivity of the virus by two orders of magnitude. This should be explained by the inactivation of the virus upon drying, irreversible sorption on the surface of the material, as well as dilution upon washing off the surface.

Irradiation for half an hour led to the complete inactivation of viruses (a decrease in the infectivity of viruses by at least three orders of magnitude), regardless of the distance to the light source.

2. An example of contact inactivation of viruses (performed at the Pasteur Institute in May 2020) on a photocatalytic membrane based on porous copper in a stationary air environment,

Samples . Microporous copper plates (plate dimensions 30x40 mm, thickness 3 mm, pore sizes from 0.5 to 20 μm) were used as a photocatalytic membrane in the tests.

The entire subsequent test procedure for inactivation of viruses on the surface of the test samples was similar to that described in example 1.

The titration results are shown in Table 2.

Table 2.

Sample Infectious
virus titer (TCID ₅₀ / ml) Microporous copper (distance to source 15 mm) 0.0 Microporous copper (distance to the source 30 mm); 0.0 Microporous copper (no irradiation) 5 × 10 ³ The initial titer of the virus in the infectious material 5 × 10 ⁵

As can be seen from the data presented, the procedure of drying the virus, followed by a half-hour exposure in air and further washing off the copper surface, led to a two-order drop in the infectivity of the virus. This is due to the inactivation of the virus upon drying, irreversible sorption on the surface of the material, as well as dilution when washed off the surface of the sample.

Irradiation for half an hour led to the complete inactivation of viruses (a decrease in the infectivity of viruses by at least three orders of magnitude), regardless of the distance to the light source.

3. An example of contact inactivation of viruses (performed at the Pasteur Institute in June 2020), on a photocatalytic element based on a ceramic porous membrane with a coating of the pore surface with copper nanoparticles in an air stationary environment ,

Samples. As a photocatalytic membrane in the tests, we used electrocorundum plates with a microporous structure (plate dimensions 30x40 mm, thickness 3 mm, pore sizes from 0.5 to 20 μm) with a coating of the pore surface with copper nanoparticles.

The entire subsequent test procedure for inactivation of viruses on the surface of the test samples was similar to that described in example 1.

The titration results are shown in Table 3.

Table 3.

Sample Virus infectious titer (TCID50 / ml) Microporous fused alumina coated with copper nanoparticles (distance to source 15 mm) 0.0 Microporous fused alumina coated with copper nanoparticles (distance to source 30 mm) 0.0 Microporous electrocorundum coated with copper nanoparticles (no irradiation) 5 × 10 ³ The initial titer of the virus in the infectious material 5 × 10 ⁵

As can be seen from the data presented, the procedure of drying the virus, followed by a half-hour exposure in air and further washing off the surface of the sample of microporous electrocorundum with a coating of the pore surface with a film of copper nanoparticles, led to a decrease in the infectivity of the virus by two orders of magnitude. This should be explained by the inactivation of the virus upon drying, irreversible sorption on the surface of the material, as well as dilution upon washing off the surface.

Irradiation of the studied samples for half an hour, as well as for samples based on microporous bronze (in example 1), led to complete inactivation of viruses (a decrease in the infectivity of viruses by at least three orders of magnitude), regardless of the distance to the light source.

4. An example of air purification and sterilization (performed at the A.A. Smorodintsev Institute of Influenza (St. Petersburg)) in June 2020, using a method based on the use of a photocatalytic membrane based on porous bronze illuminated by LEDs, through which the purified air is passed ...

Sample. A device was used as a sample for air purification and sterilization, the diagram of which is shown in Fig. 1, with an air flow rate through the photocatalytic membrane from 1 m / s to 5 m / s. A porous support based on microporous bronze 3 mm thick and 150 mm in diameter with pore sizes from 0.5 to 20 μm was used as a photocatalytic membrane. Illumination of the photocatalytic membrane during testing is performed with white light of LED matrices in the spectral range from 400 to 780 nm with a power density of 250-500 mW / cm ² .

Viruses . The process of inactivation of viruses is considered on the example of the influenza A / Puerto Rico / 8/34 (H1N1) virus, obtained from the working collection of the laboratory of chemotherapy of viral infections of the Research Institute of Influenza of the Russian Academy of Medical Sciences. It was propagated in the allantoic cavity of 10-day-old developing chicken embryos, after which the allantoic fluid from the embryos was collected, clarified by centrifugation at a speed of 7000 rpm, and then the virus was concentrated by centrifugation at a speed of 20,000 rpm. Concentrated virus with a titer of at least 10 ¹² lg TID ₅₀ / 0.1 ml was sprayed into the chamber.

Cell cultures . The experiments were carried out on an MDCK cell culture obtained from the collection of the laboratory of cell cultures of the V.I. AA Smorodintsev "of the Ministry of Health of Russia. The cell suspension (10 ⁵ cells / ml) was plated on 96-well plates and grown for a day in a CO ₂ incubator at 37 ° C and 5% CO ₂ , after which the density of the monolayer was assessed visually using an inverted microscope. Only those plates were selected for work, where the closeness of the monolayer was more than 90%.

Supportive environment. To 100 ml of DMEM medium (culture medium DMEM with glutamine, Biolot, St. Petersburg), 1 ml of antibiotic solution (ciprofloxacin, Synthesis, Kurgan) and 0.1 ml of TPCK-trypsin solution (final concentration in the medium 1 μg / ml) were added.

Aerosol system for testing the effectiveness of air disinfection.

The work was carried out in a sealed glove box, which was used as an aerosol chamber. Virus-containing liquid was nebulized using a Microlife NEB-10 medical nebulizer using mode No. 3 (particle size 10-14 microns). Air mixing with aerosol was carried out using an Orient F2035 fan. Air samples with a volume of 50 m ³ were taken using a PU-4E aspirator, passing the culture liquid through Drexel flasks to capture the virus.

Evaluation of virucidal efficacy.

Suspension containing concentrate influenza virus was sprayed and samples were taken as described, after which the titer of the virus in the samples was estimated as follows: a series of 10-fold dilutions (10^-one - ten^-7) on DMEM medium with glutamine supplemented with 20 μg / ml ciprofloxacin (a broad-spectrum antimicrobial agent of the fluoroquinolone group) and 0.5 μg / ml TPCK-trypsin, and introduced them into the wells of the plate with MDCK cells. The plates were incubated for 72 hours at 37 ° C in an atmosphere of 5% CO₂...

The virus titer was determined using the hemagglutination reaction, for which the culture medium was transferred into the corresponding wells of immunological plates with a U-shaped bottom and an equal volume of 1% suspension of chicken erythrocytes in saline was added. After 40 minutes, the presence or absence of hemagglutination in the wells was visually assessed. The virus titer was calculated by the method of Reed and Mench and expressed in 50% tissue infectious doses (TID ₅₀ ) per 200 μl volume.

Results. In the course of the experiment, a primary assessment was made of the ability of the investigated device to destroy the influenza virus in the form of an aerosol. The results are shown in Table 4.

Conclusion

In the course of this study, the virucidal efficiency of an air disinfection device based on photocatalytic membranes based on porous bronze was characterized. It is shown that the use of the investigated device leads to the complete inactivation of the influenza virus in the air.

As can be seen from the above examples of the implementation of the developed method, when testing samples of photocatalytic membranes and air disinfection devices, effective contact and photocatalytic inactivation of pathogens, including any enveloped viruses, for example, influenza and coronaviruses, on the surface of photocatalytic membranes and in the purified air is ensured. transmitted through a photocatalytic membrane based on copper or a copper-containing alloy in the form of bronze illuminated by visible light, or through a ceramic porous support with a similar microporous structure with a coating of the pore surface from copper nanoparticles. Complete inactivation of the influenza virus in the air is ensured.

Claims (1)

A method for photocatalytic purification and sterilization of air, including its passing through a photocatalytic membrane, characterized in that a porous copper-based carrier is used as a photocatalytic membrane, including microporous copper or bronze with a thickness 3 mm with pore sizes from 0.5 to 20 μm, or a porous support with a microporous structure with a coating of the pore surface of copper nanoparticles, with continuous irradiation of the photocatalytic membrane with a visible light source, which is an LED matrix, in the spectral range from 400 to 780 nm with a power density luminous flux 250-500 mW / cm²while the flow rate of the purified air through the photocatalytic membrane is maintained in the range from 1 to 5 m / s.

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