Degradable antibacterial and antiviral wood-based air filter material and preparation method thereof

Abstract

The invention relates to a degradable antibacterial and antiviral wood-based air filter material and a preparation method thereof. The preparation method comprises the steps that S1, softened wood is sliced in the direction perpendicular to the wood growth direction, and a plurality of wood chips with graded porous pore structures are obtained; s2, the prepared multiple wood chips are stacked at a preset rotation angle, and the wood-based air filter material with the stacking layer number being m is obtained; s3, preparing a treatment solution containing an aggregation-induced photosensitizer; and S4, treating the wood-based air filter material by using the treating fluid, and drying to obtain the degradable antibacterial and antiviral wood-based air filter material. The degradable antibacterial and antiviral wood-based air filter material prepared by the preparation method disclosed by the invention simultaneously has double functions of efficient interception and pathogen in-situ inactivation, is good in biodegradability and has no burden on the ecological environment, so that the degradable antibacterial and antiviral wood-based air filter material has potential advantages and huge application prospects in the fields of air pollution prevention and control, precise prevention and control of major epidemic diseases and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air filtration materials, in particular to a degradable antibacterial and antiviral wood-based air filter material and a preparation method thereof. BACKGROUND

[0002] Fresh and clean air is essential to human health. Air filtration materials can effectively filter out dust particles, bacteria, viruses, harmful gases and other pollutants in the air, which is a very important and effective way to protect people's life and health, and has become a hot research direction in the field of air purification.

[0003] A long-acting melt-blown polypropylene electret material for medical protective masks and dust masks is disclosed in Chinese patent application publication No. CN112778627A; and a PM2.5 filter using a polytetrafluoroethylene mask filter membrane is disclosed in Chinese patent application publication No. CN103585898A. However, the current filtration materials (polypropylene, polytetrafluoroethylene, etc.) are mostly derived from non-renewable petrochemical resources, are usually used once and difficult to degrade after disposal, and a large amount of use will cause resource shortage and environmental pollution. Therefore, it is urgent to develop an environmentally friendly and biodegradable new air filtration material to replace traditional petroleum-based filtration materials.

[0004] Wood is the most abundant biomass material on earth (about 3 trillion trees in the world, 400 trees per person), with the characteristics of environmental friendliness, renewability, biodegradability, and low price, excellent strength, and easy large-scale processing. It is a good substitute for traditional petrochemical materials. Wood has a naturally formed three-dimensional hierarchical interconnected multi-scale hierarchical pore structure, which is very suitable for use as a filtration material. In recent years, wood filter membranes, wood aerogel adsorption materials, wood sponges, etc. have broad application prospects in oil-water separation, selective adsorption, water pollution purification, etc. However, for air filtration, the vertically arranged microchannels (20-300 μm) in the cell structure of wood are not conducive to the interception of small pathogens (0.1-5 μm) in the air due to the excessively large pore size and excessively straight path. In addition, in addition to the interception function, the in-situ inactivation function of the captured pathogens is also crucial, which can effectively prevent the growth of live pathogens on the surface of the filter material and cause secondary infection. At present, how to engineer the pore structure of wood to achieve micro-scale pollutant interception with a simple process, and how to give the wood-based filter material antibacterial and antiviral functions to achieve in-situ broad-spectrum inactivation in a simple way are technical problems to be solved in the application of abundant and environmentally friendly wood materials in the field of efficient air purification.

[0005] A Chinese invention patent with patent application publication number CN114392611A discloses a preparation method of a wood-based composite air filter material. The method uses delignification treatment to cooperate with in-situ metal organic framework (MOF) growth, uses the pore structure of wood itself, and the polarity, coordination and electrostatic adsorption of MOF to improve the filtration efficiency of PM particles. However, the wood-based composite air filter material prepared by the patent has poor filtration effect on micro-scale pollutants such as PM2.5 (80.1%), and lacks antibacterial and antiviral functions, which limits its application in the fields of efficient air purification and pathogen protection.

[0006] A Chinese invention patent with patent application publication number CN115337792A discloses a fully biodegradable air filtration composite membrane using cellulose nanofiber as the base material and a preparation method thereof. The method atomizes cellulose nanofiber on the surface of a non-woven fabric membrane, and the fibers are separated and assembled into pores during the drying process to form an air filtration composite membrane with a porous base material as the skeleton and a multi-level network structure cellulose nanofiber as the effective core filter. The filtration efficiency of the air filtration composite membrane for 0.3 μm, 0.5 μm and 1.0 μm particles is 92%, 95% and 99%, respectively. However, the pore manufacturing process of the patent is complex, the pore structure stability control is difficult, and the patent lacks antibacterial and antiviral functions. In addition, the raw material source of the patent is single, and the TEMPO oxidized cellulose nanofiber used usually needs to be prepared through TEMPO catalytic oxidation, mechanical assistance, high-pressure homogenization and other processes, which has long processing cycle, high energy consumption and high price, and is not conducive to large-scale production.

[0007] Therefore, there is a need for a new solution. SUMMARY

[0008] The present application aims to solve the problems existing in the prior art, and provides a simple and effective degradable antibacterial and antiviral wood-based air filter and a preparation method thereof.

[0009] To achieve the above-mentioned purpose, the present application provides a preparation method of a degradable antibacterial and antiviral wood-based air filter, comprising the following steps:

[0010] Step S1, slicing the wood treated by softening in a direction perpendicular to the growth direction of the wood to obtain a plurality of wood pieces with hierarchical porous pore structures;

[0011] Step S2, stacking the prepared wood pieces at a preset rotation angle to form a wood-based air filter with a curved airflow path, wherein the effective pore size of the wood-based air filter is 0.1 μm to 0.5 μm;

[0012] Step S3, configuring a treatment liquid containing an aggregation-induced photosensitizer, wherein the aggregation-induced photosensitizer carries a positive charge and generates active oxygen under visible light excitation.

[0013] Step S4, treating the wood-based air filter material with the treatment solution, and drying to obtain the degradable antibacterial and antiviral wood-based air filter material.

[0014] Preferably, the wood is one or more of basswood, balsa wood, pine, poplar, birch.

[0015] Preferably, in step S1, the thickness of the wood pieces obtained by slicing treatment is 30-300 μm.

[0016] Preferably, in step S2, the rotation angle is selected from one or more of 90°, 60°, 45°, 30°, and the number of stacked layers m of the wood-based air filter material is 5-100.

[0017] Preferably, in step S3, the structure of the aggregation-induced photosensitizer is as follows:

[0018]

[0019] wherein n is 0-8, X is one of Cl, Br, I, PF6. - - - - -

[0020] Preferably, the structure of the aggregation-induced photosensitizer is selected from one of the following:

[0021]

[0022] Preferably, in step S3, the treatment solution is prepared with one or more of dimethyl sulfoxide, dichloromethane, tetrahydrofuran, ethanol as solvent, and the concentration of the treatment solution is 10 μM-10 mM.

[0023] Preferably, in step S4, the treatment includes loading the treatment solution on the surface of the wood-based air filter material by spraying or brushing treatment; or soaking the treatment solution into the interior of the wood-based air filter material by soaking, vacuum or pressure treatment.

[0024] The present application also provides a degradable antibacterial and antiviral wood-based air filter material prepared according to the above method, which has a curved airflow path and the effective pore size of the wood-based air filter material is 0.1-0.5 μm.

[0025] Preferably, the degradable antibacterial and antiviral wood-based air filter material intercepts pollutants of 0.1-5 μm.

[0026] ​​​​​The present application has the following beneficial effects:

[0027] 1、 The present application applies abundant and environment-friendly wood materials to efficient air purification, which can solve the environmental problems caused by the large use of non-renewable and difficult-to-degrade petroleum-based filter materials, and conforms to the principles of environmental protection and sustainable development;

[0028] 2、 The present application adopts spiral stacking of multiple wood chips to form a wood-based air filter, which can engineerically regulate and control the effective aperture and channel path of wood, and realize efficient interception of micro-scale pollutants;

[0029] 3、 By treating the wood-based air filter with the aggregation-induced photosensitizer carrying positive charges, strong active oxygen generation ability under visible light excitation, and excellent antibacterial and antiviral performance, a filter with broad-spectrum and efficient antibacterial and antiviral function can be obtained, which can solve the secondary infection problem caused by the growth of surface active pathogens of existing filters, and has potential for practical application;

[0030] 4、 The wood-based antibacterial and antiviral air filter prepared by the present application has the dual functions of efficient interception and in-situ inactivation of pathogens, and has good biodegradability and no burden on the ecological environment, so it has potential advantages and great application prospects in the fields of air pollution prevention and control, and precise prevention and control of major epidemics;

[0031] 5、 The preparation process of the present application is simple, convenient to operate, high in production efficiency, strong in product reproducibility, does not require complex and expensive equipment, has no pollution to the environment, saves energy, and is conducive to industrialization. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without creative labor:

[0033] Figure 1 The flow chart of the preparation method of the degradable antibacterial and antiviral wood-based air filter provided by the present application is shown;

[0034] Figure 2 The preparation schematic diagram of the wood-based air filter provided by the embodiment of the present application is shown;

[0035] Figure 3 The ultraviolet-visible absorption spectrum of the aggregation-induced photosensitizer DTCSPYP used in embodiments 1-3 of the present application is shown;

[0036] Figure 4Figure showing the active oxygen generation efficiency of the aggregation-induced photosensitizer DTCSPYP used in Examples 1-3 of the present application. DETAILED DESCRIPTION

[0037] For a more complete understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments described in the present specification, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0038] The following examples are used to illustrate the present application, but are not used to limit the scope of the present application. The specific techniques or conditions not specified in the examples are carried out according to the techniques or conditions described in the literature in the art, or according to the product instructions. The reagents or instruments not specified by the manufacturer are all conventional products that can be purchased through regular channels.

[0039] Figure 1 As shown in the flow chart of a preparation method of a degradable antibacterial and antiviral wood-based air filter material provided by the present application. As shown in the flow chart of a preparation method of a degradable antibacterial and antiviral wood-based air filter material provided by the present application. Figure 1 As shown, the preparation method comprises the following steps:

[0040] Step S1, slice the wood after softening treatment vertically to the growth direction of the wood to obtain a plurality of wood pieces with hierarchical porous pore structure.

[0041] Specifically, in an embodiment of the present application, the natural wood is first subjected to cooking softening treatment for 1-6 hours at a water temperature of 50-100℃. The wood is selected from one or more of basswood, balsa wood, pine, poplar and birch. The use of abundant and environmentally friendly wood materials can solve the environmental problems caused by the large-scale use of non-renewable and difficult-to-degrade petroleum-based filter materials, and conforms to the principles of environmental protection and sustainable development. Cooking softening treatment of the above wood changes the structure of the wood through heating and moist heat treatment, making it easier to process and handle in the subsequent process. Cooking softening can cause cellulose and lignin and other substances in the wood to degrade and soften to some extent, making the wood more flexible and easier to cut and process.

[0042] Specifically, in an embodiment of the present application, the wood after cooking softening is subjected to ultrathin slicing treatment vertically to the growth direction of the wood using a slicing machine, thereby obtaining a large number of ultrathin wood pieces with natural hierarchical porous pore structure. As shown in Figure 2As shown, before slicing, the wood cell structure has vertically arranged microchannels along the growth direction. The pore size of the microchannel is usually tens or hundreds of microns and the path is too straight, which is very unfavorable for the interception of tiny pathogens (0.1μm to 5μm) in the air. The wood is divided into multiple thin slices by a slicer along the growth direction, and a plurality of wood chips with the same structure can be obtained. Wood chips that are too thin are easily damaged or deformed and lack sufficient structural stability; and too small a thickness will increase the difficulty of processing, especially during cutting and handling, which is prone to damage or breakage. Excessively thick wood chips will cause the finished filter material to be too thick, affecting the convenience of use and causing waste of raw materials. Therefore, in the present application, the thickness of the wood chips obtained by slicing is 30μm to 300μm, and preferably the thickness is 40μm to 100μm;

[0043] Step S2: stacking the prepared wood chips at a preset rotation angle to form a wood-based air filter material having a curved airflow path, wherein the effective pore size of the wood-based air filter material is 0.1 μm to 0.5 μm;

[0044] Specifically, in one embodiment of the present invention, the multiple wood chips cut into thin slices in step S1 are spirally stacked at a certain rotation angle to obtain a spirally stacked wood-based air filter material, wherein the stacking process can be achieved manually or with the help of a certain machine. The structures of the wood chips prepared in step S1 are all the same, that is, if such multiple wood chips are stacked together in the same way, the apertures of the multiple wood chips still form a straight channel along the direction perpendicular to the plane where the wood chips are located. The effective aperture of the channel is usually 20μm to 300μm, which makes it impossible to intercept tiny pollutants in the air. Therefore, in the present invention, multiple wood chips are spirally stacked, that is, by rotating one layer of wood chips relative to another layer of wood chips at a certain angle, so that the apertures of the two adjacent wood chips are not aligned, thereby reducing the effective aperture of the material to 0.1μm to 0.5μm, and making the path of the airflow passing through become tortuous, thereby increasing the probability of contact with microscale (0.1μm to 5μm) pollutants in the air and increasing the possibility of being captured, thereby greatly improving the filtration efficiency. That is, Figure 2 As shown, a piece of wood is used as the first layer of wood-based air filter material. Then, another piece of wood with the same structure is rotated perpendicular to the central axis of the first layer of wood-based air filter material by a predetermined angle, and so on, so that the apertures of the two adjacent layers of wood are blocked by each other. Furthermore, in one embodiment of the present invention, the rotation angles of the two adjacent layers of wood can be the same, that is, the wood in the (i+1)th layer is rotated by the same angle relative to the wood in the (i)th layer.

[0045] Further, in another embodiment of the present application, the rotation angle between two adjacent wood pieces can be different, i.e. the rotation angle of the i+1th wood piece relative to the ith wood piece is different from the rotation angle of the i+2th wood piece relative to the i+1th wood piece. For example, the 2nd wood piece is rotated by 90° relative to the 1st wood piece, and the 3rd wood piece is rotated by 60° relative to the 2nd wood piece.

[0046] Further, in an embodiment of the present application, in order to reduce the effective pore size of the material to the greatest extent and increase the tortuosity of the path of the air flow through the filter material, thereby improving the filtration efficiency, the rotation angle is selected from one or more of 90°, 60°, 45° and 30°.

[0047] Further, in an embodiment of the present application, a lower number of stacked layers can not effectively reduce the effective pore size of the material and can not provide sufficient tortuous paths to efficiently capture micro-scale pollutants; but as the number of stacked layers increases, the manufacturing process and cost can increase significantly, and in practical applications, the filtration efficiency improvement after a certain number of layers can not be significant, but instead can increase the resistance of the air flow, resulting in an increase in energy consumption. Therefore, in the present application, the number of stacked layers m is 5-100, preferably 12-48 layers. By selecting an appropriate number of stacked layers, the balance between production cost, process complexity and energy consumption can be considered while ensuring filtration efficiency.

[0048] Since the pore size of the vertically arranged micro-channels (20-300 μm) in the wood cell structure is too large and the path is too straight, it is not conducive to the interception of small pathogens (0.1-5 μm) in the air. Therefore, in the present application, the wood pieces are stacked in multiple layers in a spiral manner, and by adjusting the rotation angle, the number of stacked layers, the thickness of the slices, the tree species and other parameters, the effective pore size of the material is reduced, and the path of the air flow through the material becomes tortuous, thereby increasing the contact probability of the material with the micro-scale (0.1-5 μm) pollutants in the air and increasing the possibility of being captured, thereby greatly improving the filtration efficiency. This method is simple and easy to implement, the pore structure is stable and controllable, and the filtration performance is excellent, so it is easy to mass-produce industrially.

[0049] Step S3, a treatment solution containing an aggregation-induced photosensitizer is configured, the aggregation-induced photosensitizer carries a positive charge and is excited by visible light to produce active oxygen;

[0050] Specifically, in an embodiment of the present application, the structure of the aggregation-induced photosensitizer is as follows:

[0051]

[0052] wherein n is 0-8, X - is Cl - , Br- , I - , PF6 - The surface of the aggregation-induced photosensitizer carries a positive charge, which makes it easy to anchor the surface negative wood matrix and pathogen contaminants. The aggregation-induced photosensitizer is easy to be excited by visible light and has excellent aggregation-induced enhanced active oxygen generation ability. Combined with its positive charge characteristics and sensitivity to visible light, it can give the wood-based air filter a broad-spectrum and efficient antibacterial and antiviral function.

[0053] Further, in an embodiment of the present application, one or more of dimethyl sulfoxide, dichloromethane, tetrahydrofuran, and ethanol is used as a solvent to prepare the treatment solution, and the concentration of the treatment solution is 10 μM to 10 mM.

[0054] Step S4, using the treatment solution to treat the wood-based air filter, and drying to obtain the degradable antibacterial and antiviral wood-based air filter.

[0055] Specifically, in an embodiment of the present application, the treatment solution prepared in step S3 is applied to the surface of the wood-based air filter by spraying or brushing.

[0056] Specifically, in another embodiment of the present application, the treatment solution prepared in step S3 is injected into the interior of the wood-based air filter by soaking, vacuum or pressure treatment.

[0057] The aggregation-induced photosensitizer with a positive charge, strong active oxygen generation ability under visible light excitation, and excellent antibacterial and antiviral performance is used to give the wood-based filter substrate a broad-spectrum and efficient antibacterial and antiviral function by simple spraying, brushing, soaking, vacuum or pressure, etc. The secondary infection problem caused by the growth of surface active pathogens of the existing filter can be solved, and it has potential for practical application.

[0058] The preparation method of the degradable antibacterial and antiviral wood-based air filter provided by the present application is as follows: the sliced wood is spirally stacked at a preset rotation angle to obtain a wood-based air filter with multiple wood sheets. The effective pore size and channel path of the wood can be effectively controlled through the rotation angle between the adjacent two wood sheets, thereby realizing efficient interception of micro-scale (0.1 μm to 5 μm) pollutants. Then, the wood-based air filter is treated with a treatment solution containing an aggregation-induced photosensitizer. The aggregation-induced photosensitizer with a positive charge and strong active oxygen generation ability under visible light excitation can give the wood-based air filter a broad-spectrum and efficient antibacterial and antiviral function. The degradable antibacterial and antiviral wood-based air filter prepared by the present application has the dual functions of efficient interception and in-situ inactivation of pathogens, and has good biodegradability and no burden on the ecological environment. Therefore, it has potential advantages and great application prospects in the fields of air pollution prevention and control and precise prevention and control of major epidemics.

[0059] Example 1

[0060] 1. Preparation of helically stacked wood-based air filter material

[0061] A natural basswood board was cooked in distilled water at 90 °C for 3 h, and then ultrathin sectioning was performed perpendicular to the growth direction of the wood to obtain a large number of ultrathin wood sheets with a natural hierarchical porous structure, the thickness of the ultrathin wood sheets being 50 μm. The prepared ultrathin wood sheets were helically stacked at the same rotation angle of 90° in a clockwise direction, the number of stacked layers being 48, to obtain a helically stacked wood-based air filter material.

[0062] 2. Preparation of aggregation-induced photosensitizer DTCSPYP

[0063] The synthetic route of the aggregation-induced photosensitizer DTCSPYP is as follows:

[0064]

[0065] Under inert gas protection, compound 2-(4-iodophenyl)acetonitrile (200 mg, 0.82 mmol), 4-ethylpyridine (93 mg, 0.9 mmol), Pd(PPh3)2Cl2(3 mg, 0.004 mmol), CuBr (2 mg, 0.014 mmol) were sequentially dissolved in diisopropanolamine (5 mL) and dimethylformamide (5 mL) solvents, and stirred at room temperature for 12 h. Subsequently, hexane / ethyl acetate (1:1.5, v / v) was used as the eluent for silica gel column chromatography purification to obtain intermediate 1 (light yellow solid) with a yield of 60%.

[0066] Under inert gas protection, intermediate 1 (100 mg, 0.45 mmol), 5-(diphenylamine)thiophene-2-carboxaldehyde (152 mg, 0.54 mmol), NaOEt (10 mg, 0.14 mmol) were dissolved in 5 mL of ethanol solvent, and stirred at 80 °C for 12 h. Recrystallization purification was performed to obtain intermediate 2 (red solid) with a yield of 85%.

[0067] Under inert gas protection, intermediate 2 (100 mg, 0.21 mmol) was dissolved in 5 mL of acetonitrile, followed by the addition of CH3CH2CH2I (60 mg, 0.42 mmol), and the reaction was refluxed under stirring at 80 °C for 12 h. Purification was performed by recrystallization to finally obtain DTCSPYP (red solid) with a yield of 90%.

[0068] The designed and synthesized DTCSPYP has a positive charge on the surface, which makes it easy to anchor the wood matrix and pathogenic fungal contaminants with a negative surface charge. The ultraviolet-visible absorption spectrum shows (see Fig. 1) that the absorption peak of DTCSPYP is at 650 nm, which is in the near-infrared region, and the absorption intensity is much higher than that of the other two photosensitizers, indicating that DTCSPYP has a strong absorption in the near-infrared region. Figure 3), DTCSPYP has a strong and wide absorption peak in the wavelength range of 400-600 nm, indicating that the designed and synthesized DTCSPYP is easy to be excited by visible light. Figure 4 For the active oxygen production efficiency of the aggregation-induced photosensitizer DTCSPYP, compared with the photosensitizer rhodamine (RB) recognized on the market for its strong active oxygen production ability, DTCSPYP has excellent aggregation-induced enhanced active oxygen production ability, and its active oxygen production efficiency is about 10 times that of RB.

[0069] 3. Preparation of degradable antibacterial and antiviral wood-based air filter material

[0070] The above-prepared DTCSPYP was dissolved in dimethyl sulfoxide to prepare a DTCSPYP mother liquor with a concentration of 1 mM. Subsequently, the above-prepared spiral-stacked wood-based air filter material was directly immersed in the DTCSPYP mother liquor, and after immersion at room temperature and normal pressure for 12 h, it was taken out. After washing and drying, the degradable antibacterial and antiviral wood-based air filter material was obtained.

[0071] Example 2

[0072] 1. Preparation of spiral-stacked wood-based air filter material

[0073] The natural pine wood board was cooked in 90°C distilled water for 3 hours, and then ultrathin sectioning was performed perpendicular to the growth direction of the wood to obtain a large number of ultrathin wood sheets with natural hierarchical porous pore structures, and the thickness of the ultrathin wood sheets was 40 μm. The prepared ultrathin wood sheets were spirally stacked in the same rotation angle of 30° clockwise, and the stacking layer number was 24, to obtain the spiral-stacked wood-based air filter material.

[0074] 2. Preparation of aggregation-induced photosensitizer DTCSPYP

[0075] The synthetic route of the aggregation-induced photosensitizer DTCSPYP is as follows:

[0076]

[0077] Under the protection of inert gas, compound 2-(4-iodophenyl)acetonitrile (200 mg, 0.82 mmol), 4-ethylpyridine (93 mg, 0.9 mmol), Pd(PPh3)2Cl2(3 mg, 0.004 mmol), CuBr (2 mg, 0.014 mmol) were sequentially dissolved in diisopropanolamine (5 mL) and dimethylformamide (5 mL) solvents, and stirred at room temperature for 12 h. Subsequently, using a silica gel column chromatography purification with hexane / ethyl acetate mixture (1:1.5, v / v) as the eluent, the intermediate 1 (light yellow solid) was obtained, and the yield was 60%.

[0078] Under inert gas protection, intermediate 1 (100 mg, 0.45 mmol), 5-(diphenylamine) thiophene-2-ethanal (152 mg, 0.54 mmol), NaOEt (10 mg, 0.14 mmol) were dissolved in 5 mL of ethanol solvent, and stirred at 80 °C for 12 h. Purification by recrystallization gave intermediate 2 (red solid) with a yield of 85%.

[0079] Under inert gas protection, intermediate 2 (100 mg, 0.21 mmol) was dissolved in 5 mL of acetonitrile, followed by the addition of CH3CH2CH2I (60 mg, 0.42 mmol), and the reaction was refluxed under stirring at 80 °C for 12 h. Purification by recrystallization gave DTCSPYP (red solid) with a yield of 90%.

[0080] 3. Preparation of degradable antibacterial and antiviral wood-based air filter

[0081] The DTCSPYP prepared above was dissolved in dichloromethane to prepare a DTCSPYP mother liquor with a concentration of 100 μΜ. The DTCSPYP mother liquor was then brushed onto the surface of the spiral-stacked wood-based air filter to obtain a degradable antibacterial and antiviral wood-based air filter.

[0082] Example 3

[0083] 1. Preparation of spiral-stacked wood-based air filter

[0084] A natural linden wood board was boiled in distilled water at 90 °C for 3 h, and then ultrathin sectioning was performed perpendicular to the growth direction of the wood to obtain a large number of ultrathin wood sheets with natural hierarchical porous pore structures, with a thickness of 50 μιη. The prepared ultrathin wood sheets were stacked in a clockwise spiral at the same rotation angle of 45°, with 32 layers of stacking, to obtain a spiral-stacked wood-based air filter.

[0085] 2. Preparation of aggregation-induced photosensitizer DTCSPYP

[0086] The synthesis route of the aggregation-induced photosensitizer DTCSPYP is as follows:

[0087]

[0088] Under inert gas protection, sequentially dissolve compound 2-(4-iodophenyl)acetonitrile (200 mg, 0.82 mmol), 4-ethylpyridine (93 mg, 0.9 mmol), Pd(PPh3)2Cl2(3 mg, 0.004 mmol), CuBr (2 mg, 0.014 mmol) in diisopropanolamine (5 mL) and dimethylformamide (5 mL) solvents, and stir at room temperature for 12 h. Then purify by silica gel column chromatography using hexane / ethyl acetate mixture (1:1.5, v / v) as eluent to obtain intermediate 1 (light yellow solid) with a yield of 60%.

[0089] Under inert gas protection, dissolve intermediate 1 (100 mg, 0.45 mmol), 5-(diphenylamine)thiophene-2-carboxaldehyde (152 mg, 0.54 mmol), NaOEt (10 mg, 0.14 mmol) in 5 mL of ethanol solvent, and stir at 80°C for 12 h. Purify by recrystallization to obtain intermediate 2 (red solid) with a yield of 85%.

[0090] Under inert gas protection, dissolve intermediate 2 (100 mg, 0.21 mmol) in 5 mL of acetonitrile, then add CH3CH2CH2I (60 mg, 0.42 mmol), and stir at 80°C for 12 h. Purify by recrystallization to obtain DTCSPYP (red solid) with a yield of 90%.

[0091] 3. Preparation of degradable antibacterial and antiviral wood-based air filter

[0092] Dissolve the prepared DTCSPYP in dimethyl sulfoxide to prepare a DTCSPYP mother liquor with a concentration of 500 μM. Then spray the DTCSPYP mother liquor onto the surface of the spiral-stacked wood-based air filter to obtain the degradable antibacterial and antiviral wood-based air filter.

[0093] Example 4

[0094] 1. Preparation of spiral-stacked wood-based air filter

[0095] Place natural pine wood plates in distilled water at 90°C for 3 h, and then make ultrathin sections perpendicular to the growth direction of the wood to obtain a large number of ultrathin wood sheets with natural hierarchical porous pore structures, the thickness of the ultrathin wood sheets being 40 μm. Stack the prepared ultrathin wood sheets in a clockwise spiral at the same rotation angle of 90°, and stack 30 layers to obtain a spiral-stacked wood-based air filter.

[0096] 2. Preparation of aggregation-induced photosensitizer DTCSPY

[0097] The synthesis route of the aggregation-induced photosensitizer DTCSPY is as follows:

[0098]

[0099] Compound 2-(4-iodophenyl)acetonitrile (200 mg, 0.82 mmol), 4- ethylpyridine (93 mg, 0.9 mmol), Pd(PPh3)2Cl2(3 mg, 0.004 mmol), CuBr (2 mg, 0.014 mmol) were sequentially dissolved in diisopropanolamine (5 mL) and dimethylformamide (5 mL) solvents under inert gas protection, and stirred at room temperature for 12 h. Then, column chromatography was performed using silica gel with hexane / ethyl acetate (1:1.5, v / v) as eluent to obtain intermediate 1 (light yellow solid) with a yield of 60%.

[0100] Intermediate 1 (100 mg, 0.45 mmol), 5-(diphenylamine)thiophene-2- carboxaldehyde (152 mg, 0.54 mmol), NaOEt (10 mg, 0.14 mmol) were dissolved in 5 mL of ethanol solvent under inert gas protection, and stirred at 80°C for 12 h. Purification was performed by recrystallization to obtain intermediate 2 (red solid) with a yield of 85%.

[0101] Intermediate 2 (100 mg, 0.21 mmol) was dissolved in 5 mL of acetonitrile under inert gas protection, followed by the addition of CH3I (60 mg, 0.42 mmol), and the reaction was refluxed under stirring at 80°C for 12 h. Purification was performed by recrystallization to obtain red solid product with a yield of 90%. Then, the obtained red solid product (50 mg, 0.08 mmol) was dissolved in acetone (10 mL) solvent, and a solution of KPF6 (1.5 g, 8 mmol) was added, and the mixture was stirred at 60°C for 4 h. Acetone was removed by distillation under reduced pressure, and column chromatography was performed using silica gel with dichloromethane / methanol (8:1, v / v) as eluent to finally obtain DTCSPY (red solid) with a yield of 80%.

[0102] 3. Preparation of degradable antibacterial and antiviral wood-based air filter

[0103] The above-prepared DTCSPY was dissolved in dichloromethane to prepare a DTCSPY mother liquor with a concentration of 2 mM. Then, the above-prepared spiral-stacked wood-based air filter was directly immersed in the DTCSPY mother liquor, and taken out after immersion at room temperature and pressure for 2 h. After washing and drying, a degradable antibacterial and antiviral wood-based air filter was obtained.

[0104] Example 5

[0105] 1. Preparation of spiral-stacked wood-based air filter

[0106] A natural birch wood board was cooked in distilled water at 90 °C for 3 hours, and then ultrathin sectioning was performed perpendicular to the growth direction of the wood to obtain a large number of ultrathin wood sheets with natural hierarchical porous pore structures, the thickness of the ultrathin wood sheets being 60 μm. The prepared ultrathin wood sheets were stacked in a clockwise spiral at the same rotation angle of 30°, the number of stacked layers being 36, to obtain a spiral-stacked wood-based air filter material.

[0107] 2. Preparation of aggregation-induced photosensitizer DTCSPY

[0108] The synthetic route of the aggregation-induced photosensitizer DTCSPY is as follows:

[0109]

[0110] Under inert gas protection, compound 2-(4-iodophenyl)acetonitrile (200 mg, 0.82 mmol), 4-ethylpyridine (93 mg, 0.9 mmol), Pd(PPh3)2Cl2(3 mg, 0.004 mmol), and CuBr (2 mg, 0.014 mmol) were sequentially dissolved in diisopropanolamine (5 mL) and dimethylformamide (5 mL) solvents, and stirred at room temperature for 12 h. Subsequently, column chromatography was performed using a silica gel column with hexane / ethyl acetate (1:1.5, v / v) as the eluent to obtain intermediate 1 (light yellow solid) at a yield of 60%.

[0111] Under inert gas protection, intermediate 1 (100 mg, 0.45 mmol), 5-(diphenylamine)thiophene-2-carboxaldehyde (152 mg, 0.54 mmol), and NaOEt (10 mg, 0.14 mmol) were dissolved in 5 mL of ethanol solvent, and stirred at 80 °C for 12 h. Recrystallization was performed to obtain intermediate 2 (red solid) at a yield of 85%.

[0112] Under inert gas protection, intermediate 2 (100 mg, 0.21 mmol) was dissolved in 5 mL of acetonitrile, followed by the addition of CH3I (60 mg, 0.42 mmol), and the reaction was refluxed under stirring at 80 °C for 12 h. Recrystallization was performed to obtain red solid product at a yield of 90%. Then, the obtained red solid product (50 mg, 0.08 mmol) was dissolved in acetone (10 mL) solvent, and a KPF6 (1.5 g, 8 mmol) solution was added, and the mixture was stirred at 60 °C for 4 h. Acetone was removed under reduced pressure, and column chromatography was performed using a silica gel column with dichloromethane / methanol (8:1, v / v) as the eluent to finally obtain DTCSPY (red solid) at a yield of 80%.

[0113] 3. Preparation of degradable antibacterial and antiviral wood-based air filter material

[0114] The prepared DTCSPY was dissolved in dichloromethane to prepare a DTCSPY mother liquor with a concentration of 1 mM. The DTCSPY mother liquor was then sprayed onto the surface of the spiral stacked wood-based air filter material to obtain the degradable antibacterial and antiviral wood-based air filter material.

[0115] Comparative Example 1

[0116] Natural basswood board with a thickness of 2 cm.

[0117] Comparative Example 2

[0118] Commercially available polypropylene filter material.

[0119] Filtering performance test

[0120] The LZC-K type automatic filtration tester was used to test the filtering performance of Examples 1-5 and Comparative Examples 1-2 on micro-scale pollutants (0.3 μm, 1 μm, 3 μm), and the results are shown in Table 1.

[0121] The results show that the degradable antibacterial and antiviral wood-based air filter material prepared in Examples 1-5 has a high filtering effect on micro-scale pollutants, which is better than the commercially available polypropylene filter material of Comparative Example 2. The natural basswood board of Comparative Example 1 has a poor filtering effect on micro-scale pollutants.

[0122] Table 1: Results of filtering performance test

[0123]

[0124]

[0125] Antibacterial and antiviral experiment

[0126] According to the Japanese Industrial Standard "Antibacterial Processed Products - Test Method for Antibacterial Properties - Antibacterial Effect" (JIS Z 2801:2010), antibacterial performance detection experiments were conducted on Examples 1-5 and Comparative Examples 1-2. The antibacterial effect of the samples was quantitatively tested using viable bacterial counting method, and the experimental results were expressed in terms of antibacterial rate. The test bacteria were Staphylococcus aureus and Candida albicans, and each group of samples was made in triplicate.

[0127] The median tissue culture infectious dose method (TCID 50 ) was used to conduct antiviral performance detection experiments on Examples 1-5 and Comparative Examples 1-2, and the experimental results were expressed in terms of antiviral rate. The test virus was influenza A virus (H1N1), and each group of samples was made in triplicate.

[0128] The experimental results are shown in Table 2.

[0129] Table 2 Antimicrobial and antiviral experiment results

[0130]

[0131]

[0132] The experimental results show that the prepared degradable antimicrobial and antiviral wood-based air filter material has remarkable antimicrobial and antiviral effects, wherein the inhibition rates of Staphylococcus aureus and influenza A virus H1N1 are both above 99%, and the inhibition rate of Candida albicans can reach 98-100%. The natural linden wood board of Comparative Example 1 and the commercial polypropylene filter material of Comparative Example 2 do not have antimicrobial and antiviral functions.

[0133] Experimental Example 3 Biodegradability experiment

[0134] According to the national standard "Determination of ultimate aerobic biodegradability of materials under controlled composting conditions" (GB / T 19277.1-2011), biodegradability experiments were performed on Examples 1-5 and Comparative Examples 1-2, and the experimental period was 45 days, and the experimental results were expressed by biodegradation rate. Each group of samples was made in triplicate.

[0135] The biodegradability experiment results are shown in Table 3.

[0136] Table 3 Biodegradability experiment results

[0137]

[0138] The experimental results show that the prepared degradable antimicrobial and antiviral wood-based air filter material has excellent biodegradability. After 45 days of degradation, the biodegradation rate can all reach above 95%. The commercial polypropylene filter material of Comparative Example 2 still maintains the original appearance after the same time, and causes long-term burden to the environment.

[0139] Although the present application has been described in detail in the foregoing with general description and specific embodiments, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application claimed.

Claims

1. A method for preparing a degradable antibacterial and antiviral wood-based air filter material, characterized by, The following steps are involved: Step S1, slicing the softened wood perpendicular to the wood growth direction to obtain a plurality of wood chips with a hierarchical porous structure; Step S2: stacking the prepared wood chips at a preset rotation angle to form a wood-based air filter material having a curved airflow path, wherein the effective pore size of the wood-based air filter material is 0.1 μm to 0.5 μm; Step S3, preparing a treatment solution containing an aggregation-inducing photosensitizer, wherein the aggregation-inducing photosensitizer carries a positive charge and is excited by visible light to generate reactive oxygen species; Step S4: treating the wood-based air filter material with the treatment liquid, and obtaining the degradable antibacterial and antiviral wood-based air filter material after drying.

2. The production method according to claim 1, wherein The wood is selected from one or more of basswood, balsa wood, pine wood, poplar wood and birch wood.

3. The production method according to claim 1, wherein In step S1 , the thickness of the wood chips obtained by the slicing process is 30 μm to 300 μm.

4. The production method according to claim 1, wherein In step S2, the rotation angle is selected from one or more of 90°, 60°, 45°, and 30°, and the number m of stacked layers of the wood-based air filter material is 5 to 100.

5. The production method according to claim 1, wherein In step S3, the structural formula of the aggregation-inducing photosensitizer is as follows: wherein n is 0 to 8, X is one of - Cl - , Br - , I - , PF6 - .

6. The production method according to claim 5, wherein The structure of the aggregation-inducing photosensitizer is selected from one of the following:

7. The production method according to claim 1, wherein In step S3, the treatment solution is prepared using one or more of dimethyl sulfoxide, dichloromethane, tetrahydrofuran, and ethanol as solvents, and the concentration of the treatment solution is 10 μM to 10 mM.

8. The production method according to claim 1, wherein In step S4, the treatment includes loading the treatment liquid onto the surface of the wood-based air filter material by spraying or brushing; or impregnating the treatment liquid into the interior of the wood-based air filter material by soaking, vacuum or pressurizing.

9. A degradable antibacterial and antiviral wood-based air filter material prepared by the production method as claimed in claims 1 - 8, characterized by The degradable antibacterial and antiviral wood-based air filter material has a curved airflow path, and the effective pore size of the wood-based air filter material is 0.1 μm to 0.5 μm.

10. The degradable antibacterial and antiviral wood-based air filter material according to claim 9, characterized in that, The degradable antibacterial and antiviral wood-based air filter material intercepts pollutants with a size of 0.1 μm to 5 μm.

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