Biodegradable bio-based cigarette filter stick capable of effectively removing ROS (reactive oxygen species) in smoke

Abstract

The invention relates to a biodegradable bio-based cigarette filter stick capable of effectively removing ROS (reactive oxygen species) in smoke and a preparation method thereof. The bio-based cigarette filter stick provided by the invention is composed of modified lyocell fibers and lignin micro-nanospheres distributed on the surfaces of the modified lyocell fibers, wherein the modified lyocell fibers comprise modified lyocell fiber tows or modified lyocell fiber non-woven fabrics. The modified lyocell fibers in the bio-based cigarette filter stick have excellent biodegradability, and the biodegradation rate in 60 days is greater than or equal to 93.3%. The modified lyocell fibers in the bio-based cigarette filter stick have excellent tar reduction and harm reduction functions, and the tar retention rate is larger than or equal to 30%. The sensory quality of a cigarette rolled by the bio-based filter stick is obviously better than that of a cigarette rolled by a cellulose acetate filter stick, and the bio-based filter stick can completely replace the cellulose acetate filter stick to be used for a traditional cigarette or a heating cigarette and is a novel green, sustainable and degradable filter material for the cigarette.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of filter rods for cigarettes, and particularly relates to a biodegradable bio-based filter rod for cigarettes which can effectively remove ROS in smoke. BACKGROUND

[0002] As the main raw material of cellulose acetate filter rods, acetate fiber (abbreviated as acetate fiber) is the second largest variety of cellulose fibers next to viscose fiber. At present, more than 90% of filter rods for cigarettes in the world use cellulose acetate. As a filter material for cigarettes, cellulose acetate has good thermal stability, can effectively intercept tar and other harmful particles in cigarettes without changing the taste of smoke, and has excellent fiber-forming properties and is easy to process and produce. However, due to the fact that the hydroxyl groups on the cellulose molecular chain are almost completely esterified, the properties of cellulose acetate are very stable, and it is difficult to degrade. Studies have shown that in a natural environment, a traditional acetate filter rod needs about 10-15 years to completely degrade. The acetyl content is the most critical factor affecting the degradation performance of cellulose acetate. The higher the acetyl content, the worse the degradation performance; the lower the acetyl content, the better the degradation performance. The degree of substitution of acetyl groups of cellulose acetate is about 2.2-2.7 (i.e. 2.2-2.7 of the 3 hydroxyl groups on each glucose unit are acetylated), and the acetyl content is about 52%-56%. A large number of acetyl groups, like "shields", surround the cellulose molecular chain, making it difficult for cellulase to recognize and contact its target (glucosidic bond). Degradation requires the sequential cooperation of two enzymes (esterase and cellulase), and high acetyl content means that the first step "deacetylation" takes a very long time. In the Directive on the Reduction of the Impact of Certain Plastic Products on the Environment (EU) 2019 / 904 issued by the United Nations in 2019, filter rods for cigarettes made of cellulose acetate are defined as "single-use plastic products" due to their slow degradation rate, and the European Union has stipulated that its member states should reduce their use by 25% by 2025. Finding a new type of filter material that can completely replace acetate fiber is a hot issue of continuous concern in the domestic and foreign tobacco industry.

[0003] Harm reduction and tar reduction are important directions for the sustainable development of the tobacco industry. Superoxide anion, hydroxyl radical, hydrogen peroxide, nitric oxide radical and other high-concentration gaseous active oxygen substances (ROS) in mainstream cigarette smoke can cause damage to lung tissue and the immune system, and effectively removing ROS in smoke and reducing the risk of diseases caused by smoking is one of the major challenges for the sustainable development of the tobacco industry. Reactive oxygen species (ROS) are a class of short-lived chemical molecules with strong oxidizing ability, including superoxide anion (•O2 －), hydrogen peroxide (H2O2), hydroxyl radical (•OH), ozone (O3) and so on, which have the effects of immunity and signal transduction, but when accumulated too much, they can cause damage to cell membranes and biological macromolecules, leading to abnormal metabolism of cells and tissues in the body, and thus causing various diseases. Smoking is one of the important exogenous sources of ROS, especially the high-temperature smoke released during the combustion of cigarettes, which is accompanied by thousands of toxic substances, including a large number of free radicals and ROS molecules. Excessive accumulation of active oxygen poses a wide and serious threat to human health. Therefore, developing green, efficient, renewable and sustainable bio-based ROS scavengers to effectively remove harmful active oxygen substances in cigarette smoke has important practical significance for reducing the harm of cigarette smoking, protecting lung tissue and alleviating the contradiction between smoking and health.

[0004] In the prior art, although paper filter rods have higher biodegradability, lower cost, and higher efficiency of trapping tar and nicotine, their large-scale commercial application is limited by their strong hygroscopicity, easy softening when wet, easy heat collapse during the smoking process, excessive adsorption of tar, and paper taste, etc. For example, patent CN109512024B paper filter rod manufacturing method, patent CN119663680A all-plant fiber paper filter rod filter core base paper and its preparation method and paper filter rod, CN119663681A paper filter material and its preparation method and application.

[0005] At present, for the particulate free radicals with larger molecular weight and higher stability in smoke, methods such as improving the trapping and adsorption efficiency of filter, increasing the permeability of cigarette paper, etc. are used to remove them; while for the gaseous free radicals with small weight and poor stability, methods such as adding free radical inhibitors, free radical scavengers, natural antioxidants, traditional Chinese medicine extracts, trace elements, natural minerals, etc. are used to remove them. Patent CN112678833B discloses a method for preparing and using nano-silicon dioxide modified squalene silicone particles for removing long-lived solid-phase free radicals and relatively short-lived gaseous-phase free radicals. However, squalene is relatively scarce and expensive, which has certain limitations in large-scale application. SUMMARY

[0006] The technical problem to be solved by the present application is to solve the bottleneck problem of the non-biodegradability of the existing cellulose diacetate filter rod and the difficulty in effectively removing ROS harmful substances in cigarette smoke. The present application provides a biodegradable bio-based filter rod for cigarette smoke that can effectively remove ROS.

[0007] Another object of the present application is to provide a preparation method of the bio-based filter rod for cigarette smoke.

[0008] The above-mentioned objects of the present application are achieved by the following technical solutions:

[0009] The application provides a biodegradable bio-based filter rod capable of effectively removing ROS in flue gas, which is composed of modified lyocell fibers and lignin micro-nano spheres distributed on the surface of the modified lyocell fibers, and the modified lyocell fibers include modified lyocell fiber tows or modified lyocell fiber non-woven fabrics.

[0010] In some embodiments, the biodegradation rate of the bio-based filter rod is greater than or equal to 93.3% after 60 days, the total particulate matter retention rate of the bio-based filter rod is greater than or equal to 35%, the tar retention rate is greater than or equal to 30%, and the nicotine retention rate is greater than or equal to 30%.

[0011] In some embodiments, the bio-based filter rod has a scavenging rate of 50% to 87% for hydroxyl radicals, a scavenging rate of 60% to 86% for superoxide anion radicals, a scavenging rate of 51% to 85% for hydrogen peroxide, a removal rate of 32% to 55% for carbon monoxide, and a removal rate of 30% to 47% for formaldehyde.

[0012] In some embodiments, the acetyl content of the modified lyocell fibers is 1% to 5%, and the surface contact angle of the modified lyocell fiber non-woven fabric is 90° to 130°.

[0013] In some embodiments, the preparation method of the modified lyocell fibers comprises the following steps:

[0014] A1: preparing an alkali solution, uniformly transferring the alkali solution to the surface of the lyocell fibers by immersion or spraying, and standing for activation for 30 minutes;

[0015] A2: transferring the activated lyocell fibers in A1 to an acetylation reagent by immersion, and reacting at 35°C to 65°C for 1 hour to 3 hours;

[0016] A3: repeatedly washing the lyocell fibers after the reaction in A2 with 60°C water and 60°C ethanol, respectively, drying the washed lyocell fibers in a 60°C oven to obtain modified lyocell fibers.

[0017] In some embodiments, the alkali solution comprises sodium hydroxide or potassium hydroxide, and the concentration of the alkali solution is 10% to 28%; and / or, the acetylation reagent is one or a combination of isopropenyl acetate, isopropenyl benzoate, methyl acrylate, ethyl acrylate, and methyl methacrylate.

[0018] In some embodiments, the preparation method of the lignin micro-nano spheres comprises the following steps:

[0019] B1: using industrial lignin as raw material, performing a demethylation reaction on the lignin raw material to obtain demethylated lignin;

[0020] B2: using anti-solvent self-assembly method, desmethyl lignin is dissolved and self-assembled, and the pore throat size is controlled to prepare lignin micro-nano sphere solution;

[0021] B3: using freeze-drying or spray drying, lignin micro-nano sphere solution is dried to obtain lignin micro-nano sphere powder.

[0022] In some embodiments, the phenolic hydroxyl content of the lignin micro-nano sphere is ≥3 mmol / g, the structure of the lignin micro-nano sphere includes solid sphere or hollow sphere containing pore throat, the particle size of the lignin micro-nano sphere is 100 nm-5000 nm, and the diameter of the pore throat is 20 nm-500 nm.

[0023] Another aspect of the present application provides a preparation method of a biodegradable bio-based filter rod capable of effectively removing ROS in flue gas, comprising: the modified lyocell fiber is sequentially subjected to bundling, curling, drying, and yarn laying to prepare a modified lyocell fiber tow, and the modified lyocell fiber tow is subjected to a filter rod forming process to prepare a bio-based filter rod; or, the modified lyocell fiber non-woven fabric is subjected to a gathering forming process to prepare a bio-based filter rod; lignin micro-nano spheres are added in the filter rod forming process to uniformly distribute on the surface of the modified lyocell fiber.

[0024] In some embodiments, the amount of lignin micro-nano spheres added in the bio-based filter rod is 0.5%-5% of the weight of the modified lyocell fiber tow or the modified lyocell fiber non-woven fabric.

[0025] The beneficial effects of the present application are:

[0026] (1) By subjecting the lyocell fiber to a heterogeneous acetylation modification reaction, the acetyl content of the modified lyocell fiber is precisely controlled to be 1%-5%, which significantly reduces the acetyl content level of the bio-based filter rod, solves the technical bottleneck of the existing acetate fiber filter rod which is difficult to degrade due to high acetyl content (52%-56%), and the bio-based filter rod prepared from the modified lyocell fiber has the potential to replace 100% of the acetate fiber filter rod.

[0027] (2) By demethylation of lignin, the phenolic hydroxyl content of lignin is greatly improved, lignin micro-nano spheres with high phenolic hydroxyl content are added to the modified lyocell fiber filter rod, and the effective capture and removal of superoxide anion, hydroxyl radical, hydrogen peroxide, and nitric oxide radical, etc. high concentration gaseous active oxygen substances (ROS) in the mainstream smoke of cigarettes are achieved, which provides a new strategy for reducing the harm of smoking, protecting lung tissue, and alleviating the contradiction between smoking and health.

[0028] (3) Modified lyocell fiber filter rod for cigarettes, which has moderate tar-reducing and harm-reducing functions, and has good interception rates for total particulate matter, tar, nicotine and other substances in cigarette smoke, and has the potential to replace acetate filter rods.

[0029] (4) Modified lyocell fiber filter rod for cigarettes, which has better sensory quality and smoking experience than acetate filter rods, significantly improves the smoking quality and taste of cigarettes, and solves the defects of paper taste and heat collapse of paper filter rods. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The surface morphology of the modified lyocell fiber in an embodiment of the present application;

[0031] Figure 2 The surface morphology of the lignin micro-nano spheres in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present application, the present application will be described more fully below, and a preferred embodiment of the present application will be given. However, the present application can be realized in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0033] The implementation of the present application will be described in detail below in combination with some embodiments and examples. The present embodiment is implemented on the premise of the technical solution of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application.

[0035] Unless otherwise stated or contradictory, the terms or phrases used herein have the following meanings:

[0036] In the present application, "multiple", "various" and the like are used without specific limitation, and refer to more than two or equal to two in number. For example, "one or more" means one or more than two.

[0037] In the present application, "further", "particularly" and the like are used for descriptive purposes, and indicate differences in content, but should not be understood as limiting the scope of protection of the present application.

[0038] In the present application, the technical features described in an open manner include both the closed technical solution consisting of the listed features and the open technical solution containing the listed features.

[0039] In the present application, when referring to a numerical interval (i.e. a numerical range), the distribution of the selectable values within the numerical interval is considered continuous and includes both numerical endpoints (i.e. the minimum and maximum values) of the numerical interval and every value between the two numerical endpoints, unless otherwise specified. When a numerical interval refers only to integers within the numerical interval, unless otherwise specified, the two endpoint integers and every integer between the two endpoints are considered to be directly enumerated, i.e. the numerical interval is equivalent to the direct enumeration of every integer within the numerical interval. When multiple numerical ranges are provided to describe a characteristic or property, the numerical ranges can be combined. In other words, unless otherwise indicated, numerical ranges disclosed herein are to be understood to include any and all sub-ranges of the same, and every number and amount within the range. A "numerical interval" can be any quantitative value, such as a number, a percentage, a ratio, etc. A "numerical interval" is intended to broadly include percentage intervals, ratio intervals, value intervals, etc.

[0040] In the present application, unless otherwise specified, a temperature parameter allows for both constant temperature treatment and for variations within a certain temperature interval. It should be understood that the constant temperature treatment allows for fluctuations within the accuracy of the instrument control. Fluctuations within a range of, for example, ±5°C, ±4°C, ±3°C, ±2°C, ±1°C are allowed.

[0041] In the present application, when referring to units of data ranges, if only the right endpoint is followed by a unit, it means that the units of the left endpoint and the right endpoint are the same. For example, 2-5h means that the units of the left endpoint "2" and the right endpoint "5" are both h (hour).

[0042] Example 1

[0043] A biodegradable bio-based filter rod for effectively removing ROS in cigarette smoke, the preparation process includes modification of lyocell fibers, preparation of lignin micro-nano spheres, preparation of modified lyocell fiber filter rod, cigarette smoke analysis and sensory quality evaluation, etc.

[0044] (1) The modification of lyocell fibers includes the following steps.

[0045] A1: Prepare a 14% concentration of NaOH lye, and use a spray method to uniformly transfer the lye to the surface of the lyocell fibers, and let it stand for activation for 30 minutes;

[0046] A2: Use an immersion method to transfer the activated lyocell fibers in A1 to acetylation reagent isopropyl acetic acid, and react at 35°C for 1.5h;

[0047] A3: Wash the lyocell fibers reacted in A2 with hot water (60°C) and hot ethanol (60°C) repeatedly, and after washing, transfer them to a 60°C oven for drying to obtain modified lyocell fibers.

[0048] (2) Preparation of lignin micro-nano spheres includes the following steps.

[0049] B1: 1 g of alkali lignin, 100 ml of deionized water and 1 g of sodium sulfite were weighed into a 250 mL three-necked flask and mixed, 2 g of sodium hydroxide solid was then added and the mixed solution was reacted at 60°C for 2 h, and then cooled to room temperature. The solution pH value was adjusted to about 2 with 12% hydrochloric acid solution, centrifuged, and the filtrate was discarded. The filter residue was washed with deionized water until the filtrate pH value was close to neutral. It was placed in a 60°C oven for drying, and after grinding, demethylated lignin was obtained.

[0050] B2: Using anti-solvent self-assembly method, the demethylated lignin was dissolved and then self-assembled, and the pore throat size was controlled to prepare lignin micro-nano sphere solution. 1 g of demethylated lignin was dissolved in a binary solvent mixture of GVL-H2O with a volume ratio of 1:1 to ensure complete dissolution of lignin and γ-valerolactone GVL. The initial binary solvent mixture was quickly added to deionized water to form a lignin micro-nano sphere dispersion.

[0051] B3: Using freeze-drying or spray-drying, the lignin micro-nano sphere solution was dried to obtain lignin micro-nano sphere powder.

[0052] (3) Preparation of modified lyocell fiber filter rod.

[0053] The modified lyocell fiber was prepared into a modified lyocell fiber tow after bundling, crimping, drying and laying. The modified lyocell fiber tow was prepared into a bio-based filter rod by a filter rod forming machine. During the filter rod forming process, 0.5% of lignin micro-nano spheres were added through a hopper device to uniformly distribute on the surface of the lyocell fiber, and a modified lyocell fiber cigarette filter rod was prepared.

[0054] (4) Analysis and evaluation.

[0055] Filter rod degradation performance and ROS scavenging capacity test.

[0056] According to GB / T 32601.1-2016, GB / T 32601.2-2016, the degradation performance of the filter rod was tested. According to the standard "DB45 / T 1494-2017 Cigarette Mainstream Smoke Gas Phase Free Radical Content Determination Electron Spin Resonance Spectroscopy", the ROS scavenging capacity of the filter rod was tested.

[0057] Cigarette smoke analysis and sensory quality evaluation.

[0058] The modified lyocell fibers prepared are connected with cigarette rods to prepare cigarettes according to GB / T19609-2004, GB23203.1-2008, GB23355-2009, GB23356-2009, and the mainstream smoke of the cigarettes is analyzed for chemical components by using a linear smoking machine and an HP7890 gas chromatograph. The sensory quality of the cigarettes is evaluated according to the tobacco industry standards YC / T 138-1998 Tobacco and Tobacco Products Sensory Evaluation Method and YC / T 497-2014 Cigarettes Chinese Cigarette Style Sensory Evaluation Method.

[0059] Example 2

[0060] The difference between Example 1 and Example 2 is that the acetylating agent in Example 2 is changed to isopropenyl benzoate, the addition amount of the lignin micro-nano spheres is 1.5%, and the rest of the experimental steps and parameters are referred to Example 1.

[0061] Example 3

[0062] The difference between Example 1 and Example 3 is that the acetylating agent in Example 3 is changed to methyl acrylate, the addition amount of the lignin micro-nano spheres is 2.5%, and the rest of the experimental steps and parameters are referred to Example 1.

[0063] Example 4

[0064] The difference between Example 1 and Example 4 is that the acetylating agent in Example 4 is changed to ethyl acrylate, the addition amount of the lignin micro-nano spheres is 3.5%, and the rest of the experimental steps and parameters are referred to Example 1.

[0065] Example 5

[0066] The difference between Example 1 and Example 5 is that the acetylating agent in Example 5 is changed to a mixture of isopropenyl acetate and isopropenyl benzoate (volume ratio 1:1), the addition amount of the lignin micro-nano spheres is 4.5%, and the rest of the experimental steps and parameters are referred to Example 1.

[0067] Example 6

[0068] The difference between Example 1 and Example 6 is that the acetylating agent in Example 6 is changed to a mixture of methyl acrylate and isopropenyl benzoate (volume ratio 1:1), the addition amount of the lignin micro-nano spheres is 5%, and the rest of the experimental steps and parameters are referred to Example 1.

[0069] Comparative Example 1

[0070] The difference between Example 1 and Comparative Example 1 is that the fiber used in Comparative Example 1 is unmodified ordinary lyocell fiber, and no lignin micro-nano spheres are added in the filter rod.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that the fiber used in Comparative Example 2 is cellulose diacetate fiber, and no lignin micro-nano spheres are added in the filter rod.

[0073] Comparative Example 3

[0074] The difference from Example 1 is that the fiber used in Comparative Example 1 is paper wood pulp fiber, and no lignin micro-nano spheres are added in the filter rod.

[0075] Comparative Example 4

[0076] The difference from Comparative Example 2 is that the fiber used in Comparative Example 4 is cellulose diacetate fiber, and 2% of lignin micro-nano spheres are added in the filter rod.

[0077] Comparative Example 5

[0078] The difference from Example 6 is that the amount of lignin micro-nano spheres added in Comparative Example 5 is 7%, and the remaining experimental steps and parameters refer to Example 6.

[0079] Table 1 Biodegradability and smoke interception rate of modified lyocell fiber filter rods

[0080]

[0081] Table 2 ROS removal capacity and sensory quality score of modified lyocell fiber filter rods

[0082]

[0083] As can be seen from Table 1, the biodegradation rate of the bio-based filter rod prepared in Examples 1-6 of the present application is higher than that of the comparative examples, and reaches more than 93%, and the harmful substances (total particulate matter, tar, nicotine) in mainstream smoke are well intercepted.

[0084] As can be seen from Table 2, the bio-based filter rod prepared in Examples 1-6 of the present application has good ROS removal capacity, and the sensory quality score is higher than that of the comparative examples. It shows that the bio-based filter rod provided in the present application has the potential to replace the existing acetate fiber filter rod and paper filter rod.

[0085] The technical features of the above-described embodiments can be combined arbitrarily, and in order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present description.

[0086] The above embodiments only express several implementation ways of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A biodegradable bio-based flue gas filter rod that effectively removes ROS from flue gas, characterized in that, The bio-based cigarette filter rod is composed of modified lyocell fibers and lignin micro-nanospheres distributed on the surface of the modified lyocell fibers. The modified lyocell fibers include modified lyocell fiber bundles or modified lyocell fiber nonwoven fabric.

2. The biodegradable bio-based tobacco filter rod that effectively removes ROS from flue gas according to claim 1, characterized in that, The biodegradation rate of the bio-based tobacco filter rod after 60 days is ≥93.3%; the total particulate matter retention rate of the bio-based tobacco filter rod is ≥35%, the tar retention rate is ≥30%, and the nicotine retention rate is ≥30%.

3. The biodegradable bio-based flue gas filter rod that effectively removes ROS from flue gas according to claim 1, characterized in that, The bio-based cigarette filter rod has a scavenging rate of 50%~87% for hydroxyl radicals, 60%~86% for superoxide anion radicals, 51%~85% for hydrogen peroxide, 32%~55% for carbon monoxide, and 30%~47% for formaldehyde.

4. The biodegradable bio-based flue gas filter rod that effectively removes ROS from flue gas according to claim 1, characterized in that, The modified lyocell fiber has an acetyl group content of 1% to 5%, and the surface contact angle of the modified lyocell fiber nonwoven fabric is 90° to 130°.

5. The biodegradable bio-based flue gas filter rod that effectively removes ROS from flue gas according to any one of claims 1 to 4, characterized in that, The method for preparing the modified lyocell fiber includes the following steps: A1: Prepare an alkaline solution and transfer it evenly to the surface of Lyocell fibers using an impregnation or spraying method, then let it stand for 30 minutes to activate. A2: Using the impregnation method, the activated Lyocell fiber in A1 is transferred to the acetylation reagent and reacted at 35℃~65℃ for 1h~3h; A3: The Lyocell fibers after the reaction in A2 were washed repeatedly with water at 60°C and ethanol at 60°C, respectively. After washing, they were transferred to an oven at 60°C to dry, thus obtaining modified Lyocell fibers.

6. The biodegradable bio-based flue gas filter rod that effectively removes ROS from flue gas according to claim 5, characterized in that, The alkaline solution includes sodium hydroxide or potassium hydroxide, and the concentration of the alkaline solution is 10% to 28%; and / or, the acetylation agent is one or a combination of several of isopropyl acetate, isopropyl benzoate, methyl acrylate, ethyl acrylate, and methyl methacrylate.

7. The biodegradable bio-based flue gas filter rod that effectively removes ROS from flue gas according to any one of claims 1 to 4, characterized in that, The preparation method of the lignin micro / nanospheres includes the following steps: B1: Using industrial lignin as raw material, the lignin raw material is subjected to a demethylation reaction to obtain demethylated lignin; B2: Using the antisolvent self-assembly method, demethylated lignin was first dissolved and then self-assembled, while simultaneously controlling the pore throat size to prepare a lignin micro-nanosphere solution; B3: The lignin micro-nanosphere solution is dried by freeze drying or spray drying to obtain lignin micro-nanosphere powder.

8. The biodegradable bio-based flue gas filter rod that effectively removes ROS from flue gas according to claim 7, characterized in that, The phenolic hydroxyl content of the lignin micro-nanospheres is ≥3 mmol / g, the structure of the lignin micro-nanospheres includes solid spheres or hollow spheres with pore throats, the particle size of the lignin micro-nanospheres is 100nm~5000nm, and the diameter of the pore throats is 20nm~500nm.

9. A method for preparing a biodegradable bio-based tobacco filter rod that can effectively remove ROS from flue gas, as described in any one of claims 1 to 8, characterized in that, include: The modified lyocell fibers are sequentially bundled, crimped, dried, and filament-arranged to obtain modified lyocell fiber bundles. The modified lyocell fiber bundles are then processed into bio-based filter rods using a filter rod forming process. Alternatively, the modified lyocell fiber nonwoven fabric is processed into bio-based filter rods using a gathering and forming process. Lignin micro-nanospheres are added during the filter rod molding process to ensure they are evenly distributed on the surface of the modified lyocell fiber.

10. The method for preparing a biodegradable bio-based tobacco filter rod that effectively removes ROS from flue gas according to claim 9, characterized in that, The amount of lignin micro-nanospheres added to the bio-based cigarette filter rod is 0.5% to 5% of the weight of the modified lyocell fiber tow or the modified lyocell fiber nonwoven fabric.

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