Biomass carbon dot-based modification agent for bamboo cell wall and application thereof in bamboo antiseptic and mold-proof

Abstract

The application discloses a kind of bamboo cell wall modifiers based on biomass carbon dots and its application method in bamboo preservative and mildew-proof;Among them, the preparation method of modifier includes: biomass waste is used as carbon source, which is crushed, sieved and dried to absolute dryness, to obtain absolute dry wood powder;Absolute dry wood powder and zinc gluconate are added to deionized water for stirring;After stirring is completed, the mixture is transferred to hydrothermal reaction kettle for heating reaction;After reaction is completed, cool to room temperature, filter the filtrate and centrifuge, to obtain zinc-doped carbon dot solution;Polyethylene glycol aqueous solution is stirred with zinc-doped carbon dot solution, then the mixed solution is filtered, the filtered solution is centrifuged and the supernatant is dialyzed through dialysis bag to remove unreacted polyethylene glycol, to obtain polyethylene glycol modified zinc-doped carbon dot preparation;The moso bamboo modified by the preparation shows excellent corrosion resistance and mildew resistance, meeting the demand of material performance in the field of building, furniture and the like.

Description

Technical Field

[0001] This invention belongs to the field of bamboo functional improvement technology, specifically relating to a bamboo cell wall modifier based on biomass carbon dots and its application in bamboo preservation and mildew prevention. Background Technology

[0002] Moso bamboo is one of the most widely distributed, abundant, and fully utilized bamboo species in my country. It boasts advantages such as a short growth cycle, strong regeneration ability, and excellent mechanical properties, making it widely used in construction, furniture, decoration, packaging, landscaping, and other fields. It plays a significant role in alleviating the supply and demand imbalance of timber, promoting sustainable forestry development, and contributing to the achievement of carbon neutrality goals. However, under natural conditions, moso bamboo is susceptible to decay fungi and mold, and its inherent anti-corrosion and anti-mold properties are relatively poor, severely limiting its long-term application and service life in outdoor and high-humidity environments. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a bamboo cell wall modifier based on biomass carbon dots and its application in bamboo preservation and mildew prevention.

[0004] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention proposes a method for preparing a bamboo cell wall modifier based on biomass carbon dots, comprising the following steps: S1: Using biomass waste as a carbon source, crush, sieve and dry to absolute dryness to obtain absolute dry wood powder; S2: Weigh out oven-dried wood powder and zinc gluconate at a mass ratio of 1:2, then add them to deionized water and stir to mix. S3: After stirring, transfer the mixture to a hydrothermal reactor and react at 200±5℃ for 6~8 h; S4: After the reaction is complete, cool to room temperature, filter, collect the filtrate, and centrifuge to obtain a zinc-doped carbon dot solution; S5: Mix the polyethylene glycol aqueous solution with the prepared zinc-doped carbon dot solution by stirring. Then filter the mixture, centrifuge the filtered solution, and take the supernatant for dialysis through a dialysis bag to remove unreacted polyethylene glycol, thereby obtaining a polyethylene glycol-modified zinc-doped carbon dot formulation.

[0005] Furthermore, in step S1, cedar biomass waste is used as a carbon source, which is crushed through a 60-mesh sieve and dried to absolute dryness at 60±2℃.

[0006] Furthermore, in step S2, oven-dried wood flour and zinc gluconate are added to deionized water at a mass-to-volume ratio of 1:20 (g / mL), and then stirred at 500 r / min for 15±5 min.

[0007] Furthermore, in step S4, a 0.22 μm filter membrane is used for filtration, the filtrate is collected, and the filtrate is placed in a centrifuge and centrifuged at 8000 r / min for 10 min to obtain a zinc-doped carbon dot solution.

[0008] Furthermore, in step S5, the volume ratio of the polyethylene glycol aqueous solution to the prepared zinc-doped carbon dot solution is 1:1; the concentration of the polyethylene glycol aqueous solution is 0.1 mg / mL, and the molecular weight of the polyethylene glycol is 200.

[0009] Furthermore, in step S5, the polyethylene glycol aqueous solution and the zinc-doped carbon dot solution are magnetically stirred and mixed at room temperature for 24 h. The resulting mixture is filtered through a 0.22 μm filter membrane, and the filtered solution is centrifuged at 8000 r / min for 10 min. The supernatant is then dialyzed in a 1000 Dalton dialysis bag for 24 h to remove unreacted polyethylene glycol, thus obtaining a polyethylene glycol-modified zinc-doped carbon dot formulation.

[0010] In a second aspect, the present invention proposes a bamboo cell wall modifier based on biomass carbon dots, which is prepared by the preparation method described in the first aspect.

[0011] In a third aspect, the present invention proposes the application of bamboo cell wall modifiers based on biomass carbon dots as described in the second aspect in the preservation and mildew prevention of bamboo.

[0012] In a fourth aspect, the present invention proposes a process for preparing modified bamboo using a formulation, comprising: 1): Soften the bamboo after removing the green and yellow parts; 2): The softened bamboo is impregnated in the bamboo cell wall modifier based on biomass carbon points as described in claim 7, and then subjected to ultrasonic treatment; 3): After soaking for another 24 hours at room temperature, remove the bamboo and let it stand at room temperature for 12 hours. Then dry it at 103±5℃ to obtain bamboo modified by the preparation.

[0013] Furthermore, the softening treatment in step 1) is as follows: soak in boiling water for 30 minutes, then soak in room temperature deionized water for 30 minutes, repeat this process until the bamboo block sinks to the bottom of the water to obtain softened bamboo. In step 2), the softened bamboo is immersed in the bamboo cell wall modifier based on biomass carbon dots and sonicated for 60 min at 80% power.

[0014] The beneficial effects of this invention are as follows: This invention provides a polyethylene glycol-modified zinc-doped carbon dot formulation, which is loaded into the internal structure of moso bamboo. The modified moso bamboo exhibits excellent corrosion resistance and mildew resistance, meeting the material performance requirements of the construction, furniture and other fields.

[0015] Carbon dots, as a novel zero-dimensional carbon-based nanomaterial, possess characteristics such as small particle size, good water solubility, high biocompatibility, wide availability of raw materials, non-toxicity or low toxicity, and excellent antibacterial and antifungal properties, demonstrating great potential in the field of biomass material modification. This invention modifies the structure and properties of carbon dots through metal ion doping, further enhancing their surface activity, photocatalytic performance, and antibacterial ability. Specifically, zinc-doped carbon dots not only retain the excellent properties of carbon dots but also achieve broad-spectrum inhibition of decay fungi and molds through the slow release of zinc ions and the synergistic effect of carbon dots, while simultaneously improving the interfacial bonding of the material. Polyethylene glycol (PEG), as a non-toxic, water-soluble polymer with high affinity for cellulose, can penetrate the cell walls of bamboo, fill pores, and occupy hydroxyl sites, acting as a dispersant and modifier to improve the dispersibility and fixation rate of zinc-doped nanomaterials in bamboo. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0017] Figure 1 The graph shows the inhibitory effect of unmodified bamboo (a) and modified bamboo (b) on brown rot fungi.

[0018] Figure 2 The graph shows the inhibitory effect of unmodified bamboo (a) and modified bamboo (b) on Aspergillus niger. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1 This embodiment provides a modified bamboo material, the preparation process of which includes the following steps: (1) Preparation of zinc-doped carbon dots Using thinned fir and other biomass waste as a carbon source, the waste was first pulverized and sieved through a 60-mesh sieve. Then, it was dried to absolute dryness at 60±2℃. Appropriate amounts of absolute dry wood powder and zinc gluconate were weighed at a mass ratio of 1:2 and added to deionized water at a mass-to-volume ratio of 1:20 (g / mL). The mixture was stirred at 500 r / min for 15±5 min on a magnetic stirrer. After stirring, the mixture was transferred to a polytetrafluoroethylene-lined hydrothermal reactor and reacted at 200±5℃ for 6–8 h. After the reaction was complete, the reactor was removed, cooled to room temperature, and filtered through a 0.22 μm filter membrane. The filtrate was then centrifuged at 8000 r / min for 10 min to obtain a zinc-doped carbon dot solution.

[0020] (2) Preparation of polyethylene glycol-modified zinc-doped carbon dot formulations A polyethylene glycol aqueous solution with a molecular weight of 200 and a concentration of 0.1 mg / mL was prepared and mixed with the prepared zinc-doped carbon dot solution at a volume ratio of 1:1. After stirring magnetically at room temperature for 24 h, the solution was filtered through a 0.22 μm filter membrane. The resulting solution was centrifuged again at 8000 r / min for 10 min. The supernatant was then dialyzed in a 1000 Dalton dialysis bag for 24 h to remove unreacted polyethylene glycol, thus obtaining a polyethylene glycol-modified zinc-doped carbon dot formulation.

[0021] (3) Preparation process of bamboo modified by formulation The bamboo material, after removing the green and yellow parts, was softened (i.e., soaked in boiling water for 30 minutes, then soaked in room temperature deionized water for 30 minutes, and this process was repeated until the bamboo pieces sank to the bottom of the water to obtain softened bamboo material). The softened bamboo material was then immersed in the polyethylene glycol-modified zinc-doped carbon dot preparation prepared above, and ultrasonicated for 60 minutes at 80% power. After that, it was immersed at room temperature for 24 hours, removed and left to stand at room temperature for 12 hours, and then dried at 103±5℃ to finally obtain bamboo material modified by the preparation.

[0022] Comparative Example 1 The bamboo used in this comparative example is unmodified bamboo.

[0023] Effect test The bamboo materials provided in Example 1 and Comparative Example 1 were subjected to tests for corrosion resistance and mildew resistance. The test methods are as follows: A) Corrosion resistance test The decay and mildew resistance tests were conducted according to the Chinese national standard "Durability of Wood: Laboratory Test Methods for Natural Resistance to Decay" (GB / T 13942.1-2009) and the European Committee for Standardization standard "Durability of Wood and Wood-based Products: Determination of Natural Resistance of Solid Wood to Wood-Damaging Fungi - Test Methods - Part 1: Basidiomycetes" (CEN / TS 15083-1-2005).

[0024] a. Preparation and sterilization of culture medium Accurately weigh 46 g of PDA powder and add it to 1000 mL of deionized water. Heat and stir at 60°C until the solution is completely dissolved. Then, transfer the solution to a wide-mouth Erlenmeyer flask and autoclave it at 121°C for 20 minutes. After sterilization, place the Erlenmeyer flask on a sterile laminar flow hood and pour potato agar medium into petri dishes to prepare a solid culture medium.

[0025] b. Activation culture of microbial strains Using an inoculation spatula, mycelial blocks were cut from cryopreserved white-rot and brown-rot fungi and placed in the center of the PDA medium. After sealing with sealing film, the medium was placed in a biochemical incubator at 28 °C for activation culture for 7 days.

[0026] c. Secondary culture of the bacterial strain Using an inoculation spatula, cut a piece of mycelium from the edge of a actively growing colony within the activated culture medium and place it in the center of a fresh PDA medium. Seal the medium with sealing film and place it in a biochemical incubator at 28 ℃ until the mycelium has grown to two-thirds of the volume of the culture dish.

[0027] d. Preparation and sterilization of bamboo blocks Both modified and unmodified bamboo were wrapped in sterile gauze and waterproof kraft paper and sterilized at 121°C for 30 minutes. After sterilization, they were cooled to room temperature in a sterile environment for later use.

[0028] e. Inoculation and cultivation of bamboo blocks The sterilized bamboo blocks were placed in a culture dish with good mycelial growth, sealed with sealing film, and placed in a biochemical incubator at 28°C for 12 weeks under dark conditions.

[0029] f. Bamboo block processing and quality determination After a 12-week incubation period, the mycelium on the surface of the specimen was scraped off, and the specimen was dried in a drying oven at 103±2℃ until constant weight. The mass of the specimen at this point was recorded as M3. The mass loss rate was calculated according to the following formula to complete the corrosion resistance test.

[0030]

[0031] In the formula: ML—mass loss of bamboo blocks after the corrosion resistance test, % M2—Dry weight of bamboo block before corrosion resistance test, g; M3 — The fully dry weight of the bamboo block after the corrosion resistance test, in grams.

[0032] B) Anti-mold test The anti-mold test was conducted in accordance with GB / T 18261—2013, "Test Methods for the Control Efficacy of Anti-mold Agents against Wood Molds and Discoloration Fungi".

[0033] a. Culture medium preparation: Accurately weigh 46 g of PDA powder and add it to 1000 mL of deionized water. Heat and stir at 60 ℃ until the solution is completely dissolved. Then, transfer the solution to a wide-mouth Erlenmeyer flask and place it in an autoclave. Sterilize at 121 ℃ for 20 min. After sterilization, place the Erlenmeyer flask on a sterile laminar flow hood and pour potato agar medium into petri dishes to prepare a solid culture medium.

[0034] b. Culture of test bacteria: On a clean bench, Aspergillus niger and Trichoderma viride were inoculated onto the prepared culture medium. Each type of mold was inoculated into 6 culture dishes. After sealing with sterile sealing film, the dishes were placed in a constant temperature and humidity incubator for culture at a temperature of 25±2℃ and a relative humidity of 85±5% for 7 days.

[0035] c. Preparation of mycelium and spore suspension: On a clean bench, use an inoculation loop to pick up the mycelium and spores of the mold, put them into a sterile grinder for grinding, then pour them into an Erlenmeyer flask containing glass beads after mold treatment, add an appropriate amount of sterile water, place it on a shaker for shaking treatment, set the speed to 150 r / min, and the time to 15 min to obtain a suspension for inoculation.

[0036] d. Inoculation and Cultivation of Bamboo Cubes: Using a sterile syringe, aspirate the mycelium and spore suspension onto a clean bench and inject it into a petri dish containing agar medium. Shake the dish to ensure even distribution on the surface. Immediately after inoculation, place the dish in a constant temperature and humidity incubator (28℃, 85% relative humidity) for 7 days until colonies mature, ready for inoculation of bamboo cubes. Before inoculation, wrap the bamboo cubes in multiple layers of gauze and sterilize them with steam at 100℃ for 2 hours. Allow them to cool before inoculation. Under aseptic conditions, place the bamboo cubes into the petri dish. Immediately after inoculation, return the dish to the constant temperature and humidity incubator (28℃, 85% relative humidity) and cultivate for 4 weeks.

[0037] e. Evaluation method: After 4 weeks of inoculation and culture of bamboo blocks, the area of ​​bacterial infection is visually tested, mainly to check the degree of bacterial infection on the sample surface. The infection value is graded according to Table I. The lower the infection value, the higher the anti-mold effect. The control efficacy against the two molds is calculated based on the average infection value of the bamboo blocks, as shown in the following formula (1).

[0038] Table I. Grading of Mold Surface Infection Values ​​for Different Samples

[0039] (1) In the formula: E—prevention and control efficacy, % D1—The average infection value of bamboo surface after formulation modification; D0—Average infection value of unmodified bamboo surface.

[0040] The specific test results are as follows: (1) Brown rot fungus and Aspergillus niger were inoculated onto the bamboo materials of Example 1 and Comparative Example 1, respectively, and their resistance to decay and mold were tested. The anti-decay and anti-mold effects of the bamboo material modified by the formulation (Example 1) and the unmodified bamboo material (Comparative Example 1) are shown in the figures below. Figure 1 and Figure 2 .from Figure 1 and Figure 2 It is clearly visible that the surface of the culture medium for unmodified bamboo was covered with bacterial colonies, demonstrating a very strong ability for colony reproduction. After modification, no visible colony growth was observed on the surface of the bamboo, with only traces of the inoculation point remaining.

[0041] (2) White rot fungus and brown rot fungus were inoculated on the bamboo material of Example 1 respectively for rot resistance test. The test results are shown in Table 1 below.

[0042] Table 1. Anti-corrosion properties of modified bamboo

[0043] As can be seen from the data in Table 1, the modified bamboo prepared in Example 1 has an excellent inhibitory effect on both white rot fungi and brown rot fungi, and can effectively prevent the bamboo from decaying.

[0044] (3) The bamboo material of Example 1 was inoculated with Trichoderma viride and Aspergillus niger respectively for anti-mold test. The test results are shown in Table 2 below.

[0045] Table 2 Anti-mildew properties of modified bamboo

[0046] As can be seen from the data in Table 2, the modified bamboo prepared in Example 1 has an excellent inhibitory effect on both Trichoderma viride and Aspergillus niger, and can effectively prevent bamboo from becoming moldy.

[0047] In summary, the bamboo modified by the present invention exhibits excellent corrosion resistance and mildew resistance, which can meet the material performance requirements of fields such as construction and furniture, and has excellent application prospects.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a bamboo cell wall modifier based on biomass carbon dots, characterized in that, Includes the following steps: S1: Using biomass waste as a carbon source, crush, sieve and dry to absolute dryness to obtain absolute dry wood powder; S2: Weigh out oven-dried wood powder and zinc gluconate at a mass ratio of 1:2, then add them to deionized water and stir to mix. S3: After stirring, transfer the mixture to a hydrothermal reactor and react at 200±5℃ for 6~8 h; S4: After the reaction is complete, cool to room temperature, filter, collect the filtrate, and centrifuge to obtain a zinc-doped carbon dot solution; S5: Mix the polyethylene glycol aqueous solution with the prepared zinc-doped carbon dot solution by stirring. Then filter the mixture, centrifuge the filtered solution, and take the supernatant for dialysis through a dialysis bag to remove unreacted polyethylene glycol, thereby obtaining a polyethylene glycol-modified zinc-doped carbon dot formulation.

2. The method for preparing the bamboo cell wall modifier based on biomass carbon dots according to claim 1, characterized in that, In step S1, cedar biomass waste is used as a carbon source. It is crushed through a 60-mesh sieve and dried at 60±2℃ until completely dry.

3. The method for preparing the bamboo cell wall modifier based on biomass carbon dots according to claim 1, characterized in that, In step S2, oven-dried wood flour and zinc gluconate were added to deionized water at a mass-to-volume ratio of 1:20 (g / mL), and then stirred at 500 r / min for 15±5 min.

4. The method for preparing the bamboo cell wall modifier based on biomass carbon dots according to claim 1, characterized in that, In step S4, a 0.22 μm filter membrane is used for filtration, the filtrate is collected, and the filtrate is placed in a centrifuge and centrifuged at 8000 r / min for 10 min to obtain a zinc-doped carbon dot solution.

5. The method for preparing the bamboo cell wall modifier based on biomass carbon dots according to claim 1, characterized in that, In step S5, the volume ratio of the polyethylene glycol aqueous solution to the prepared zinc-doped carbon dot solution is 1:1; the concentration of the polyethylene glycol aqueous solution is 0.1 mg / mL, and the molecular weight of the polyethylene glycol is 200.

6. The method for preparing the bamboo cell wall modifier based on biomass carbon dots according to claim 5, characterized in that, In step S5, the polyethylene glycol aqueous solution and the zinc-doped carbon dot solution were magnetically stirred and mixed at room temperature for 24 h. The resulting mixture was filtered through a 0.22 μm filter membrane. The filtered solution was centrifuged at 8000 r / min for 10 min. The supernatant was dialyzed in a 1000 Dalton dialysis bag for 24 h to remove unreacted polyethylene glycol, thus obtaining a polyethylene glycol-modified zinc-doped carbon dot formulation.

7. A bamboo cell wall modifier based on biomass carbon dots, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 6.

8. The application of the bamboo cell wall modifier based on biomass carbon dots as described in claim 7 in the preservation and mildew prevention of bamboo.

9. A process for preparing modified bamboo using a formulation, characterized in that, include: 1): Soften the bamboo after removing the green and yellow parts; 2): The softened bamboo is impregnated in the bamboo cell wall modifier based on biomass carbon points as described in claim 7, and then subjected to ultrasonic treatment; 3): After soaking for another 24 hours at room temperature, remove the bamboo and let it stand at room temperature for 12 hours. Then dry it at 103±5℃ to obtain bamboo modified by the preparation.

10. The process for preparing modified bamboo using a formulation according to claim 9, characterized in that, The softening process in step 1) is as follows: soak in boiling water for 30 minutes, then soak in room temperature deionized water for 30 minutes, repeat this process until the bamboo block sinks to the bottom of the water to obtain softened bamboo. In step 2), the softened bamboo is immersed in the bamboo cell wall modifier based on biomass carbon dots and sonicated for 60 min at 80% power.

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