RU2747332C1 - Photoactive cuvette - Google Patents

Abstract

FIELD: purification and disinfection of air.

SUBSTANCE: invention relates to a technology for purification and disinfection of air and aqueous media and optical elements of medical equipment. A photoactive cell is proposed, which is a flow-through device made in the form of a tubular structure made of quartz glass, formed by through channels of a capillary type, on the surface of which a photoactive layer is applied, having a thickness of 0.1-2.0 mcm and consisting of nanoparticles of zinc and magnesium oxides and silver additives with the following ratio of components, wt. %: ZnO 79.5-99; MgO 0.9-20; Ag 0.01-1.00.

EFFECT: increased ability of the flow cell to photogenerate reactive singlet oxygen, which actively decomposes organic contaminants and pathogens, is achieved by applying a layer of zinc and magnesium oxide nanoparticles containing a modifying additive of silver to the inner surface of the quartz capillary elements.

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Description

The invention relates to a technology for purification and disinfection of air and aqueous media and optical elements of medical equipment, in particular, it is a flow cell capable of photogeneration of reactive singlet oxygen, which actively decomposes organic pollution and pathogens.

Photochemical water purification is widely used for the decomposition of organic pollutants, disinfection of premises and disinfection of liquid media (Basov L.L., Moskvichev I.Yu., Chikhachev KS Method for photochemical water purification and a device for its implementation; RF Patent No. 2636076, published 20.11.2017 according to IPC indices C02F 9/12, C02F 1/32, C02F 1/78, B01D 19/00, C02F 1/66, B01D 36/00; Boltenkov IS, Kolobkova EV, Evstropiev SK Synthesis and characterization of transparent photocatalytic ZnO-Sm ₂ O ₃ and ZnO-Er ₂ O ₃ coatings. // Journal of Photochemistry and Photobiology A: Chemistry, 2018, V. 367, P. 458-464; Evstropiev SK, Dukelskii KV, Karavaeva AV, Vasilyev VN, Kolobkova EV, Nikonorov NV, Evstropyev KS Transparent bactericidal ZnO nanocoatings. Journal of Materials Science: Materials in Medicine, 2017, V. 28, No. 7, Article 102; doi: 10.1007 / s10856-017-5909-4). Most often, UV irradiation is used for photochemical cleaning and disinfection of water, air, and the surface of solids. The antibacterial action and decomposition of organic contaminants in solutions under the action of UV radiation is associated with the formation under its action of chemically active forms of oxygen (singlet oxygen, hydroxyl radicals, peroxide radicals) (Y. Li, W. Zhang, J. Niu, Y. Chen , Mechanism of photogenerated reactive oxygen species and correlation with the antibacterial properties of engineered metal-oxide nanoparticles.ACS Nano, 2012, V. 6, P. 5164-5173), (Kiselev BM, Evstropyev S.K., Starodubtsev AM Photocatalytic degradation and sorption of methylene blue on the surface of metal oxides in an aqueous solution of a dye. // Optics and Spectroscopy, 2017, T. 123, No. 5, pp. 798-805).

In many works, to speed up the processes of purification and disinfection of aqueous media, special additives are introduced into them that release reactive oxygen species and oxidize organic compounds. So, RF patent No. 2636076 and work (MD Hernandez-Alonso, JM Coronado, A. Javier Maira, J. Soria, V. Loddo, V. Augugliaro. Ozone enhanced activity of aqueous titanium dioxide suspensions for photocatalytic oxidation of free cyanide ions. Appl. Catal. B: Environ., 2002, V. 39, No. 3, P. 257-267) describe the process of photolytic ozonation of water. In (Ju He, Wanhong Ma, Jianjun He, Jincai Zhao, JC Yu, Photooxidation of azo dye in aqueous dispersions of H ₂ O ₂ / α-FeOOH. Appl. Catal. B: Environ., 2002, V. 39, No. 3, P. 211-220) hydrogen peroxide additives were used to accelerate the photodegradation of organic pollutants. It should be noted that the use of such photodegradable additives leads to an increase in the cost of cleaning processes from organic contaminants and disinfection. In addition, hydrogen peroxide is an unstable compound that spontaneously decomposes over time even in the absence of light.

Therefore, in recent decades, various solid bactericidal and photocatalytic materials have been used as additives that significantly accelerate the cleaning and disinfection processes [4,7] (Y. Li, W. Zhang, J. Niu, Y. Chen, Mechanism of photogenerated reactive oxygen species and correlation with the antibacterial properties of engineered metal-oxide nanoparticles.ACS Nano, 2012, V. 6, P. 5164-5173), (Kiselev BM, Evstropiev S.K., Starodubtsev AM Photocatalytic degradation and sorption of methylene blue on the surface metal oxides in an aqueous solution of a dye. // Optics and Spectroscopy, 2017, T. 123, No. 5, pp. 798-805).

Various flow-through devices are widely used for photo processing of air and aqueous media, the advantages of which are high productivity and efficiency (RF Patent No. 2636076; Photochemical reactor for water treatment and water purification system. Description of the utility model to RF patent No. 110084, publ. 10.11.2011 on IPC indices C02F 9/12, C02F 1/32, C02F 103/04). Flow-through devices providing UV treatment of blood are described in USSR author's certificates No. 1042758 "Method for ultraviolet irradiation of blood and a device for its implementation", priority 17.02.1982, and No. 1437938 "Device for ultraviolet irradiation of blood", priority 21.11.1986, published by IPC index A61N 5/06). In flow-through devices made of quartz glass and described in these copyright certificates, there is no bactericidal or photocatalytic component and the effect of UV treatment is carried out due to the effect of radiation on oxygen compounds contained in the blood.

Nanoparticles of oxide semiconductors are significantly more stable photogenerators of synthlet oxygen, which ensure the removal of organic impurities and high antibacterial activity [2,4,7]. When exposed to light, these oxide materials are capable of releasing reactive oxygen species that attack pathogens and oxidize organic contaminants.

The closest to the proposed technical solution is a flow-through generator of singlet oxygen, which can be used for cleaning and disinfecting air, described in [9] (IV Bagrov, IM Belousova, AS Grenishin, VM Kiselev. , Kislyakov IM, Sosnov EN Singlet oxygen generator of gas-flow type based on porous fullerene-containing structures // Opt. Spectrum 2012. T. 112. No. 6. P. 1009). A significant drawback of this generator is the use of fullerene as a photoactive element, which has a low photostability and weak adhesion to the flow cell material, which determines the low stability and low time resource of such devices.

The objective of the invention is to develop an effective photoactive flow cell containing photostable oxide nanoparticles and allowing UV treatment of air and liquid media for their disinfection and cleaning from organic contaminants.

The technical result of the invention is to increase the ability of the flow cell to photogenerate chemically active singlet oxygen, which actively decomposes organic contaminants and pathogens, is achieved by applying a layer of zinc and magnesium oxide nanoparticles containing a modifying additive of silver to the inner surface of the quartz capillary elements.

The problem of the invention is solved by using layers of photoactive oxide nanoparticles deposited on the inner surface of the capillary channels of a photoactive flow cell - a singlet oxygen generator. The flow cell is made of quartz glass, which ensures high transparency of its walls in the UV and visible spectral ranges, which makes it possible to use all the light energy of the radiation source.

The new photoactive cell is a flow-through device made in the form of a tubular silica glass container formed by through capillary-type channels, on the surface of which a photoactive layer is applied, having a thickness of 0.1-2.0 μm and consisting of nanoparticles of zinc and magnesium oxides and silver additives with the following ratio of components, wt. %: ZnO 79.5-99; MgO 0.9-20; Ag 0.01-1.00.

The presented drawings illustrate the essence of the invention:

FIG. 1 is a diagram illustrating the structure and principle of operation of a photoactive cell, where 1 denotes the cell body, 2 - quartz capillaries forming through channels, 3 - photoactive layers deposited on the inner walls of quartz capillaries 2.

FIG. 2 shows a micrograph of a cross-section of a photoactive cell.

FIG. 3 shows the luminescence spectrum of a photoactive cell under the action of radiation with a wavelength of λ = 370 nm.

The diameter of the channels of the cuvette can vary within wide limits depending on the state of aggregation of the medium being treated, as well as the nature and degree of its contamination, and is preferably 0.05 ÷ 10 mm. A layer of zinc and magnesium oxide nanoparticles containing a modifying additive of silver is deposited on the inner surface of the channels.

The thickness of the layer of nanoparticles applied to the inner surface of the channels is preferably 0.1–2.0 μm. When the thickness of the nanoparticle layer exceeds 2.0 μm, the efficiency of the photoactive action of the cell decreases due to the strong absorption of light by the channels closest to the light source. When the thickness of the photoactive layer applied to the inner surface of the channels of the photoactive cell is less than 0.1 μm, the oxygen generation efficiency is insufficient to effectively remove organic contaminants.

The generation of reactive oxygen species is carried out on the surface of photoactive particles [2,4,7]. Therefore, the specific surface area of the photoactive layer and the size of its constituent nanocrystals are essential for the efficient generation of singlet oxygen. It has been experimentally established that the optimal size of nanocrystals is 15–70 nm. When the crystal size is less than 15 nm, the effect of the quantum size effect becomes significant - an increase in the band gap of zinc oxide, which leads to a narrowing of the spectral range of external radiation, leading to the generation of reactive oxygen species on its surface. With an increase in the nanocrystal size over 70 nm, the efficiency of singlet oxygen generation decreases due to a decrease in the specific surface area of the layer particles.

The introduction into the composition of the film-forming solution of a soluble polymer - polyvinylpyrrolidone provides high adhesion of the solution to the surface of quartz glass.

Table 2 shows data on the relative intensity of singlet oxygen generation by photoactive coatings of various chemical compositions. The relative values of the intensity of the generation of singlet oxygen were determined based on the intensity of the luminescence peak (λ _max = 1270 nm) by the coatings. The highest intensity of the luminescence peak observed in the spectra of the synthesized photoactive coatings was taken as 100 relative units (sample 3, Table 2). The intensity of the singlet oxygen luminescence peaks in the spectra of other coatings was noticeably lower.

The boundaries of the optimal chemical compositions of photoactive coatings that most actively generate singlet oxygen under the action of light were determined by us as corresponding to the compositions of coatings in which the relative intensity of singlet oxygen generation is 50 relative units. The technical result is proven in the stated ranges of the constituent components of the coating (Table 2, samples: 2, 3, 4, 7, 8, 9, 12, 13, 14). For comparison, compositions with other values of the content of components are shown - samples: 1, 5, 6, 10, 11, 15, which do not give sufficient generation of singlet oxygen.

Zinc oxide is the main component responsible for the release of singlet oxygen under UV irradiation. When it contains more than 99 wt% zinc oxide, the efficiency of singlet oxygen generation decreases due to the formation of large crystals and a decrease in the specific surface area of the layer material, which provides the generation of singlet oxygen.

When the zinc oxide content is less than 79.5 wt%, the efficiency of singlet oxygen generation decreases due to a decrease in the content of the main photoactive component.

With small additions of magnesium oxide to coatings based on zinc oxide, the size of ZnO crystals decreases [12] and their specific surface area increases. Therefore, the introduction of small additions of magnesium oxide increases the ability of the photoactive layer to generate singlet oxygen under the action of UV radiation. When the content of magnesium oxide is less than 0.9 wt% in the photoactive layer, this positive effect is practically not manifested.

When the content of magnesium oxide is more than 20 wt%, the content of photoactive components - zinc oxide and silver decreases and the efficiency of generation of singlet oxygen becomes low.

The introduction of silver as a modifying component into the composition of the photoactive layer increases its bactericidal and photocatalytic properties. At a silver content of more than 1 wt%, molecular clusters and silver nanoparticles are formed in the layer, which strongly absorb light in the near UV and visible parts of the spectrum, which reduces the efficiency of singlet oxygen generation by a photoactive cell.

When the silver content is less than 0.01 wt%, the efficiency of singlet oxygen generation by the photoactive layer is noticeably reduced.

All the stated ranges of the concentration of the components in the photoactive layer are optimal to achieve the stated result. A specific example of implementation.

A capillary blank 70 mm long and 3 mm in diameter, made of quartz glass, was used as the base of the photoactive cell. Inside the workpiece, there were tubular channels open at both ends and having a diameter of 0.07–0.25 mm. The spatial arrangement of the air channels is shown in the micrograph of the blank end shown in Figure 2.

For application to the inner surface of the channels, a film-forming solution was prepared (Table 1). The introduction of a soluble polymer, polyvinylpyrrolidone, into the composition of the film-forming solution ensured high adhesion of the solution to the quartz glass surface.

The air passages of the preform were filled with a film-forming solution under reduced pressure and dried for 24 hours at room temperature. Upon completion of drying, the workpiece was placed in an electric furnace and heat treated at 550 ° C for 2 hours. In the course of heat treatment, there was a complete decomposition of metal nitrates and polyvinylpyrrolidone, removal of gaseous products and the formation of a homogeneous and transparent oxide coating.

The determination of the ability of the synthesized oxide coatings to generate singlet oxygen was carried out by measuring the photoluminescence spectra of the coatings in the near-IR region of the spectrum according to the method described in [7]. The luminescence spectra were studied on an SDH-IV spectrometer (SOLAR Laser Systems, Republic of Belarus).

Figure 3 shows the photoluminescence spectrum of the cuvette upon excitation with light with a wavelength of λ = 370 nm. _{The spectrum contains a} rather intense luminescence band with λ max = 1270 nm, which is characteristic of singlet oxygen [9]. Our experiments have shown that the developed cuvette efficiently generates singlet oxygen both under the action of near-UV radiation and under the action of blue light.

Literature

1. Basov L.L., Moskvichev I.Yu., Chikhachev K.S. Method for photochemical water purification and device for its implementation. RF patent 2636076 (IPC C02F 9/12, C02F 1/32, C02F 1/78, B01D 19/00, C02F 1/66, B01D 36/00, priority date 02.12.2015, publication date 20.11.2017).

2. Boltenkov I.S., Kolobkova E.V., Evstropiev S.K. Synthesis and characterization of transparent photocatalytic ZnO-SrmOa and ZnO-Er203 coatings. // Journal of Photochemistry and Photobiology A: Chemistry, 2018, V. 367, P. 458-464.

3. Evstropiev S.K., Dukelskii K.V., Karavaeva A.V., Vasilyev V.N., Kolobkova E.V., Nikonorov N.V., Evstropyev K.S. Transparent bactericidal ZnO nanocoatings. Journal of Materials Science: Materials in Medicine. 2017. V. 28. No. 7. Article 102.doi: 10.1007 / s10856-017-5909-4.

4. Y. Li, W. Zhang, J. Niu, Y. Chen, Mechanism of photo generated reactive oxygen species and correlation with the antibacterial properties of engineered metal-oxide nanoparticles. ACS Nano. 2012. V. 6. P. 5164-5173.

5. M.D. Hernandez-Alonso, J.M. Coronado, A. Javier Maira, J. Soria, V. Loddo, V. Augugliaro. Ozone enhanced activity of aqueous titanium dioxide suspensions for photocatalytic oxidation of free cyanide ions. Appl. Catal. B: Environ. 2002. V. 39. No. 3. P. 257-267.

6. Ju He, Wanhong Ma, Jianjun He, Jincai Zhao, JC Yu, Photooxidation of azo dye in aqueous dispersions of H ₂ O ₂ / α-FeOOH. Appl. Catal. B: Environ., 2002, V. 39, No. 3, P. 211-220.

7. Kiselev B.M., Evstropiev S.K., Starodubtsev A.M. Photocatalytic degradation and sorption of methylene blue on the surface of metal oxides in an aqueous solution of a dye. // Optics and Spectroscopy. 2017.Vol. 123. No. 5. S. 798-805.

8. Zyryanov V.V. Photochemical reactor for water treatment and water purification system. Description of the utility model to RF patent No. 110084, IPC C02F 9/12, C02F 1/32, C02F 103/04, priority date 06/02/2011, publication date 11/10/2011.

9. Bagrov I.V., Belousova I.M., Grenishin A.S., Kiselev V.M., Kislyakov I.M., Sosnov E.N. Gas-flow singlet oxygen generator based on porous fullerene-containing structures // Optics and Spectroscopy. 2012. T. 112. No. 6. S. 1009.

10. Popov Yu.V., Kukui L.M. Method for ultraviolet irradiation of blood and a device for its implementation. A.S. THE USSR. No. 1042758. Priority 02/17/1982. IPC A61N 5/06.

11. Popov Yu.V., Kukui LM, Kirichek BI, Finkelstein BB, Sorokina OG, Chechin SD Device for ultraviolet irradiation of blood. A.S. USSR No. 1437038. Priority 11/21/1986, IPC A61N 5/06.

12. Evstropiev S.K., Soshnikov LP., Kolobkova E.V., Evstropyev K.S., Nikonorov N.V., Khrebtov A.I., Dukelskii K.V., Kotlyar K.P., Oreshkina K.V., Nashekin A.V. Polymer-salt synthesis and characterization of MgO-ZnO ceramic coatings with the high transparency in UV spectral range. // Optical Materials. 2018. V. 82. P. 81-87.

Claims (1)

A photoactive cuvette for cleaning and disinfecting air and aqueous media, which is a flow-through device made in the form of a tubular structure made of quartz glass, formed by through channels of a capillary type, on the surface of which a photoactive layer is applied having a thickness of 0.1-2.0 μm and consisting of nanoparticles of zinc and magnesium oxides and silver additives with the following ratio of components, wt. %: ZnO 79.5-99; MgO 0.9-20; Ag 0.01-1.00.

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