Preparation method of silver-titanium dioxide nanocomposite material and its application in leather cultural relic protection

Abstract

The present invention belongs to the field of cultural relic protection applications, and specifically discloses a method for preparing a silver-titanium dioxide nanocomposite material and its application in leather cultural relic protection. The preparation method of the composite material comprises the following steps: (1) mixing a silver nitrate solution with a chestnut tannin solution to obtain a silver nitrate-chestnut tannin solution; (2) dissolving n-butyl titanate in anhydrous ethanol to obtain an n-butyl titanate solution, adding the n-butyl titanate solution to the silver nitrate-chestnut tannin solution and mixing uniformly to obtain a mixed solution; (3) subjecting the mixed solution to a hydrothermal reaction, and after the reaction is completed, centrifuging, washing, drying, and calcining to obtain a silver-titanium dioxide nanocomposite material. The present invention can be applied in a wide range of leather cultural relic protection and restoration projects, and has a high degree of flexibility and applicability. This wide applicability gives the present invention greater application potential in the field of cultural relic protection and can meet the protection needs of different types of leather cultural relics.

Description

Technical Field

[0001] The invention belongs to the application field of cultural relic protection, and specifically discloses a preparation method of a silver-titanium dioxide nanocomposite material and application of the silver-titanium dioxide nanocomposite material in leather cultural relic protection. Background Art

[0002] Leather artifacts, as an important component of cultural heritage, carry rich historical, cultural, and artistic value. However, during long-term preservation, leather materials are susceptible to erosion by factors such as light, oxidation, and microorganisms, leading to discoloration, decay, and aging. Traditional cultural relic conservation techniques typically rely on chemical protective agents, such as detergents, reinforcements, and mounting adhesives. Detergents include water, organic solvents, and oxidants (such as chloramine T, hydrogen peroxide, hypochlorite, and chlorine dioxide); reinforcements generally include cellulose ethers, acrylic resins, fluororesins, and parabens, or reinforcing materials such as plastic film and screen; mounting adhesives include starch paste, carboxymethyl cellulose, and cellulose diacetate, and are used to repair organic artifacts such as paper and silk. In addition, polymer materials can also be used as reinforcement materials, adhesives, and surface sealing materials in cultural relic conservation. These include natural organic polymers (such as polysaccharides, proteins, and waxes) and synthetic resins (such as water-soluble synthetic resins, solvent-based synthetic resins, reactive polymers, and polymer resin emulsions).

[0003] However, these methods often have limitations, such as complex preparation, suboptimal results, and secondary damage to cultural relics. Specifically, traditional detergents, due to their strong oxidizing properties, can cause color changes on the surface of cultural relics, embrittlement of the material, and potential chemical corrosion. Reinforcement materials such as acrylic resins have poor weather resistance, are prone to failure, and may degrade into harmful small molecules. Therefore, for biomass-based cultural relics, especially leather artifacts, traditional conservation materials and methods may alter the texture and appearance of the artifacts, affecting their historical value. Summary of the Invention

[0004] In view of the problems and shortcomings of the existing technology, the present invention provides a silver-titanium dioxide nanocomposite material suitable for the protection of leather cultural relics, and also provides a corresponding preparation method.

[0005] Based on the above purpose, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for preparing a silver-titanium dioxide nanocomposite material, comprising the following steps:

[0007] (1) mixing a silver nitrate solution with a chestnut extract solution to obtain a silver nitrate-chestnut extract solution;

[0008] (2) dissolving n-butyl titanate in anhydrous ethanol to obtain an n-butyl titanate solution, adding the n-butyl titanate solution to the silver nitrate-chestnut extract solution and mixing them uniformly to obtain a mixed solution;

[0009] (3) subjecting the mixed solution to a hydrothermal reaction, and after the reaction is completed, centrifuging, washing, drying, and calcining to obtain a silver-titanium dioxide nanocomposite material.

[0010] Preferably, the mass fraction of silver nitrate in the silver nitrate solution in step (1) is 1% to 10%, and the mass fraction of chestnut tannin in the chestnut tannin solution is 5% to 15%; and the weight ratio of the silver nitrate solution to the chestnut tannin solution is (0.5 to 5.0):1.0.

[0011] Preferably, the weight ratio of n-butyl titanate to anhydrous ethanol in step (2) is 1:(10-30).

[0012] More preferably, the weight ratio of the n-butyl titanate solution to the silver nitrate-chestnut extract solution is (10-30):1.

[0013] More preferably, the mixing time is 30 minutes.

[0014] Preferably, the hydrothermal reaction temperature in step (3) is 120-160° C., and the reaction time is 2-6 hours.

[0015] More preferably, the hydrothermal reaction vessel is a stainless steel reactor lined with polytetrafluoroethylene.

[0016] More preferably, the centrifugal speed is 3000-6000 rpm, and the time is 20-60 min.

[0017] More preferably, the cleaning process is: cleaning with deionized water and ethanol three times respectively.

[0018] More preferably, the drying temperature is 100-150° C., and the drying time is 10-20 h.

[0019] More preferably, the calcination temperature is 300-800° C., and the calcination time is 1-5 hours.

[0020] In a second aspect, the present invention provides a silver-titanium dioxide nanocomposite material prepared by the preparation method described in the first aspect.

[0021] In a third aspect, the present invention provides an application of the silver-titanium dioxide nanocomposite material described in the second aspect in the protection of leather cultural relics.

[0022] In a fourth aspect, the present invention provides a method for applying the silver-titanium dioxide nanocomposite material described in the second aspect in the protection of leather cultural relics, which is: ultrasonically dispersing the silver-titanium dioxide nanocomposite material in water to obtain a dispersed solution, and spraying or immersing the dispersed solution on the surface of the leather cultural relic.

[0023] Preferably, the weight ratio of the silver-titanium dioxide nanocomposite material to water is 1:1000-4000.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention uses chestnut tannin extract in chestnut extract as a template. Chestnut tannin extract not only has a specific polyphenol structure, but also can promote the formation of titanium dioxide nanoparticles as a template, and can also act as a reducing agent to convert Ag into + The silver is then reduced to nano-silver particles, which serve as nuclei for the growth of titanium dioxide, resulting in silver-titanium dioxide nanoparticles. The addition of chestnut wood and silver also reduces the particle size of the nanoparticles, helping to control their shape and size, increase their specific surface area, and thus enhance their photocatalytic activity and UV light absorption.

[0026] 2. The chestnut tannin extract used in the present invention is a natural biological resource. The preparation process reduces the harmful substances that may be produced in the chemical synthesis method. It belongs to green synthesis preparation and reduces the risk of environmental pollution. At the same time, the use of chestnut tannin extract as a template makes the synthesis of TiO2 and Ag + The reduction is completed in the same step, which simplifies the preparation process of titanium dioxide nanoparticles and can greatly shorten the preparation time cost compared with the sol-gel method.

[0027] 3. The silver-titanium dioxide nanocomposite material of the present invention has excellent ultraviolet shielding ability, preventing the deterioration and fading of leather caused by ultraviolet radiation; the present invention has excellent antibacterial properties, which can effectively prevent leather cultural relics from corruption, mildew and other problems caused by microbial invasion; the present invention has good antioxidant properties, which can effectively prevent leather cultural relics from losing their original color and texture due to oxidation reactions; the present invention has stable physical and chemical properties and can maintain its performance under various environmental conditions; the present invention takes into account the problem of minimizing the impact on the texture and appearance of leather cultural relics, and the fine structure and distribution of the silver-titanium dioxide nanocomposite material ensure that the original texture of the leather cultural relics will not be destroyed.

[0028] 4. The present invention provides a flexible preparation method based on a formula design, allowing the ratio of silver to titanium dioxide to be adjusted during the preparation process to meet the needs of different cultural relic preservation projects. This feature enables the present invention to be applied in a wide range of leather cultural relic preservation and restoration projects, with high flexibility and applicability. This broad applicability gives the present invention greater application potential in the field of cultural relic preservation, and can meet the protection needs of different types of leather cultural relics. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 (A, a) is a transmission electron microscopy image of the titanium dioxide nanomaterial prepared in Comparative Example 1, Figure 1 (B, b) is a transmission electron microscopy image of the titanium dioxide nanomaterial prepared in Comparative Example 2. Figure 1 (C, c) are transmission electron micrographs of the silver-titanium dioxide nanocomposite prepared in Example 1;

[0030] Figure 2 (A, a) is a scanning electron microscope image of the titanium dioxide nanomaterial prepared in Comparative Example 1, Figure 2 (B, b) is a scanning electron microscope image of the titanium dioxide nanomaterial prepared in Comparative Example 2. Figure 2 (C, c) is a scanning electron microscope image of the silver-titanium dioxide nanocomposite material prepared in Example 1. Figure 2 (c1, c2, c3) are element distribution diagrams of Ti, O, and Ag on the surface of the silver-titanium dioxide nanocomposite prepared in Example 1;

[0031] Figure 3 X-ray diffraction (XRD) spectra of the nanomaterials prepared in Example 1 and Comparative Examples 1-2;

[0032] Figure 4 The particle size distribution diagram of the silver-titanium dioxide nanocomposite prepared in Example 1 and Comparative Example 3;

[0033] Figure 5 (A, a) is a transmission electron microscopy image of the titanium dioxide nanomaterial prepared in Comparative Example 1, Figure 5 (B, b) is a transmission electron micrograph of the silver-titanium dioxide nanocomposite material prepared in Example 1. Figure 5 (C, c) is a transmission electron micrograph of the silver-titanium dioxide nanocomposite material prepared in Example 2. Figure 5 (D, d) is a transmission electron micrograph of the silver-titanium dioxide nanocomposite prepared in Comparative Example 4;

[0034] Figure 6 The graph shows the test results of the ultraviolet shielding performance of the nanomaterials prepared in Examples 1, 3, 4, and Comparative Examples 1 and 2;

[0035] Figure 7The antioxidant capacity test results of the nanomaterials prepared in Examples 1, 3, 4, and Comparative Examples 1 and 2 are shown;

[0036] Figure 8 The particle size distribution diagram of the nanomaterials prepared in Examples 1, 3, 4, and Comparative Examples 1 and 2;

[0037] Figure 9 The antibacterial performance test results of the nanomaterials prepared in Examples 1, 3, 4, and Comparative Example 2 are shown;

[0038] Figure 10 This is a comparison chart of the surface color difference and antibacterial ability of leather before and after treatment in Example 5. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clear and distinct, the present invention is further described in detail below through examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] Example 1

[0041] A silver-titanium dioxide nanocomposite material, the preparation method thereof comprises the following steps:

[0042] (1) dissolving silver nitrate in deionized water to obtain a silver nitrate solution with a mass fraction of 2%, dissolving chestnut tannin extract in deionized water, centrifuging, and filtering to obtain a chestnut tannin extract solution with a mass fraction of 10%; mixing the silver nitrate solution and the chestnut tannin extract solution in a volume ratio of 1:2 to obtain a silver nitrate-chestnut tannin extract solution;

[0043] (2) Dissolve 1 mL of n-butyl titanate in anhydrous ethanol and dilute to 20 mL to obtain a n-butyl titanate solution; add the obtained n-butyl titanate solution dropwise to 1.5 mL of silver nitrate-chestnut extract solution and mix at room temperature for 30 minutes to obtain a mixed solution;

[0044] (3) The mixed solution was transferred to a stainless steel reactor lined with polytetrafluoroethylene and subjected to hydrothermal reaction at 140°C for 4 h. After the reaction, the mixture was centrifuged at 4000 rpm for 30 min. The precipitate was washed with deionized water and ethanol three times, dried at 120°C for 16 h, and then calcined in a muffle furnace at 500°C for 3 h to obtain a silver-titanium dioxide nanocomposite material.

[0045] Comparative Example 1

[0046] A titanium dioxide nanomaterial, the preparation method thereof comprises the following steps:

[0047] (1) Dissolve 1 mL of n-butyl titanate in anhydrous ethanol and dilute to 20 mL to obtain a n-butyl titanate solution; add 1 part of the n-butyl titanate solution dropwise to 50 parts of deionized water and mix at room temperature for 30 minutes to obtain a mixed solution;

[0048] (2) The mixed solution was transferred to a stainless steel reactor lined with polytetrafluoroethylene and subjected to hydrothermal reaction at 140°C for 4 h. After the reaction, the mixture was centrifuged at 4000 rpm for 30 min. The precipitate was washed with deionized water and ethanol three times, dried at 120°C for 16 h, and then calcined in a muffle furnace at 500°C for 3 h to obtain titanium dioxide nanomaterials.

[0049] Comparative Example 2

[0050] A titanium dioxide nanomaterial, the preparation method thereof comprises the following steps:

[0051] (1) dissolving chestnut tannin extract in deionized water, centrifuging, and filtering to obtain a chestnut tannin extract solution with a mass fraction of 10%;

[0052] (2) dissolving 1 part of n-butyl titanate in 20 parts of anhydrous ethanol to obtain a n-butyl titanate solution; adding the obtained n-butyl titanate solution dropwise to 1.5 mL of the chestnut tannin extract solution, and mixing at room temperature for 30 minutes to obtain a mixed solution;

[0053] (3) The mixed solution was transferred to a stainless steel reactor lined with polytetrafluoroethylene and subjected to hydrothermal reaction at 140°C for 4 h. After the reaction, the mixture was centrifuged at 4000 rpm for 30 min. The precipitate was washed with deionized water and ethanol three times, dried at 120°C for 16 h, and then calcined in a muffle furnace at 500°C for 3 h to obtain titanium dioxide nanomaterials.

[0054] The nanomaterials prepared in Example 1 and Comparative Examples 1-2 were subjected to transmission electron microscopy (TEM). The transmission electron microscopy results (TEM) are as follows: Figure 1 .in, Figure 1 (A, a) is a transmission electron microscopy image of the titanium dioxide nanomaterial prepared in Comparative Example 1, Figure 1 (B, b) is a transmission electron microscopy image of the titanium dioxide nanomaterial prepared in Comparative Example 2. Figure 1 (C, c) is a transmission electron micrograph of the silver-titanium dioxide nanocomposite material prepared in Example 1.

[0055] from Figure 1 (A, B, C) It can be seen that nanomaterials are composed of small particles of tens of nanometers. Figure 1 (a, b) are HRTEM images of titanium dioxide nanoparticles with a lattice spacing of 0.35 nm, which is consistent with the (101) crystal plane of anatase titanium dioxide. Figure 1(c) is the HRTEM image of Ag, with a lattice spacing of 0.20 nm, which is consistent with the (200) lattice spacing of silver.

[0056] The nanomaterials prepared in Example 1 and Comparative Examples 1-2 were subjected to scanning electron microscopy. Figure 2 .in, Figure 2 (A, a) is a scanning electron microscope image of the titanium dioxide nanomaterial prepared in Comparative Example 1, Figure 2 (B, b) is a scanning electron microscope image of the titanium dioxide nanomaterial prepared in Comparative Example 2. Figure 2 (C, c) is a scanning electron microscope image of the silver-titanium dioxide nanocomposite material prepared in Example 1. Figure 2 (c1, c2, c3) are element distribution diagrams of Ti, O, and Ag on the surface of the silver-titanium dioxide nanocomposite material prepared in Example 1.

[0057] from Figure 2 (A, a) It can be seen that the size of the nanoparticles synthesized in Comparative Example 1 is about 200 nm, but they are prone to agglomeration. Figure 2 (B, b) It can be seen that the addition of chestnut wood extract in Comparative Example 2 can make the nanoparticles form shorter rod-shaped aggregates with more regular structure and more uniform particle size. Figure 2 (C, c) It can be seen that the addition of silver in Example 1 increases the surface roughness, provides more reaction sites, and helps to improve its reaction activity. Figure 2 The EDS spectra of (c1, c2, c3) show that Ti, O, and Ag elements exist and are evenly dispersed in Example 1.

[0058] The nanomaterials prepared in Example 1 and Comparative Examples 1-2 were analyzed by XRD, and the crystallinity of the nanoparticles was determined by their diffraction peaks. The results are as follows: Figure 3 Wherein, TiO2 is the titanium dioxide nanomaterial prepared in Comparative Example 1, CT is the titanium dioxide nanomaterial prepared in Comparative Example 2, and CTA is the silver-titanium dioxide nanocomposite material prepared in Example 1.

[0059] from Figure 3 It can be seen that the peaks of titanium dioxide prepared in Example 1 and Comparative Examples 1-2 are 25.3°, 37.8°, 48.0°, 53.9°, 55.1°, 62.7°, 68.8°, 70.3° and 75.1°, corresponding to the crystal planes (101), (004), (200), (105), (211), (204), (116) and (220) of anatase titanium dioxide, respectively. In addition, the silver-titanium dioxide nanocomposite material synthesized in Example 1 has diffraction peaks of 38.1°, 44.3°, 64.5° and 77.4°, corresponding to the crystal planes (111), (200), (220) and (311) of silver, respectively.

[0060] Figure 1 、 2 3. This demonstrates that the nanomaterials prepared in Example 1 and Comparative Examples 1-2 are titanium dioxide with an anatase structure. The crystal structure of the composite material is a key factor in determining its photoreaction efficiency. Of the two most common crystal forms of titanium dioxide, anatase crystals have a relatively higher photoreaction activity than rutile crystals. Furthermore, the silver nanoparticles in Example 1 have a face-centered cubic (fcc) structure, indicating successful silver doping.

[0061] Comparative Example 3

[0062] A silver-titanium dioxide nanocomposite material, the preparation method thereof comprises the following steps:

[0063] (1) dissolving silver nitrate in deionized water to obtain a 2% by mass silver nitrate solution, dissolving quebracho extract in deionized water, centrifuging, and filtering to obtain a 10% by mass quebracho extract solution; mixing the silver nitrate solution and the quebracho extract solution in a volume ratio of 1:2 to obtain a silver nitrate-quebracho extract solution;

[0064] (2) Dissolve 1 ml of n-butyl titanate in anhydrous ethanol and dilute to 20 ml to obtain a n-butyl titanate solution; add the obtained n-butyl titanate solution dropwise to 1.5 ml of silver nitrate-quebracho tannin solution and mix at room temperature for 30 minutes to obtain a mixed solution;

[0065] (3) The mixed solution was transferred to a stainless steel reactor lined with polytetrafluoroethylene and subjected to hydrothermal reaction at 140°C for 4 h. After the reaction, the mixture was centrifuged at 4000 rpm for 30 min. The precipitate was washed with deionized water and ethanol three times, dried at 120°C for 16 h, and then calcined in a muffle furnace at 500°C for 3 h to obtain a silver-titanium dioxide nanocomposite material.

[0066] The particle size of the silver-titanium dioxide nanocomposite materials prepared in Example 1 and Comparative Example 3 was measured using a dynamic light scattering method. The results are shown in FIG. Figure 4 .

[0067] from Figure 4It can be seen that compared with Comparative Example 1, the titanium dioxide synthesized from chestnut wood extract has a smaller molecular particle size and a narrower particle size distribution. This is because quebracho extract (quebracho tannin) is a condensed tanning agent that is prone to condensation and hydrolysis reactions when heated. On the one hand, it will form a larger molecular particle size, causing the titanium dioxide molecular particle size using it as a template to increase. On the other hand, it will decompose into small molecular phenolic substances, ultimately causing the molecular weight distribution to become wider. Chestnut wood extract (chestnut tannin) is a hydrolyzed tanning agent that undergoes a hydrolysis reaction when heated, thereby obtaining titanium dioxide with a smaller molecular particle size and a narrower particle size distribution, which helps to improve its photocatalytic activity and ultraviolet light absorption capacity.

[0068] Example 2

[0069] A silver-titanium dioxide nanocomposite material, whose components and preparation method are basically the same as those in Example 1, except that the mass fraction of chestnut tannin extract in the chestnut tannin extract solution in step (1) is 5%.

[0070] Comparative Example 4

[0071] A silver-titanium dioxide nanocomposite material, whose components and preparation method are basically the same as those in Example 1, except that the mass fraction of chestnut tannin extract in the chestnut tannin extract solution in step (1) is 20%.

[0072] (1) Electron microscope transmission test

[0073] The silver-titanium dioxide nanocomposites prepared in Examples 1, 2, and Comparative Examples 1 and 4 were subjected to electron microscopy. The results are shown in FIG. Figure 5 .in, Figure 5 (A, a) is a transmission electron microscopy image of the titanium dioxide nanomaterial prepared in Comparative Example 1, Figure 5 (B, b) is a transmission electron micrograph of the silver-titanium dioxide nanocomposite material prepared in Example 1. Figure 5 (C, c) is a transmission electron micrograph of the silver-titanium dioxide nanocomposite material prepared in Example 2. Figure 5 (D, d) is a transmission electron micrograph of the silver-titanium dioxide nanocomposite material prepared in Comparative Example 4.

[0074] from Figure 5 It can be seen that because chestnut extract (chestnut tannin) contains abundant hydroxyl groups, which can alter the surface properties of particles and affect the dispersibility of the nanoparticles. When the mass fraction of chestnut tannin extract is increased from 5% to 10%, the particles have better dispersibility and easily form micron-sized particles. However, when the addition amount is increased to 20%, the nanoparticles agglomerate severely, becoming a single entity. Therefore, in the embodiment, when the mass fraction of chestnut tannin extract is 10%, the particle dispersibility is the best.

[0075] Example 3

[0076] A silver-titanium dioxide nanocomposite material, whose components and preparation method are basically the same as those in Example 1, except that the mass fraction of silver nitrate in the silver nitrate solution in step (1) is 6%.

[0077] Example 4

[0078] A silver-titanium dioxide nanocomposite material, whose components and preparation method are basically the same as those in Example 1, except that the mass fraction of silver nitrate in the silver nitrate solution in step (1) is 10%.

[0079] (2) UV shielding performance test

[0080] The nanomaterials prepared in Examples 1, 3, 4, and Comparative Examples 1 and 2 were tested for their UV shielding properties using the UV-visible light diffuse reflection method. The test results are as follows: Figure 6 .

[0081] from Figure 6 It can be seen that the addition of chestnut tannin extract in Comparative Example 2 enhances the material's absorption capacity in the visible light region compared to Comparative Example 1. Furthermore, in Examples 1, 3, and 4, as the silver content increases, the absorption capacity in the visible light range increases, while the absorption capacity in the ultraviolet range decreases.

[0082] The Kubelka-Munk equation was used to calculate the band gap of the synthesized nanoparticles. The formula is as follows:

[0083]

[0084] Where hv is the photon energy, α is the absorption coefficient, A is the proportional constant, and Eg is the band gap width. In a geometric sense, it represents the intercept of the linear part of the curve on the x-axis. For indirect band gap semiconductors, n = 2.

[0085] Calculations show that, compared with Comparative Example 1, the addition of chestnut extract in Comparative Example 2 reduces Eg from 3.2eV to 3.18eV. In Examples 1, 3, and 4, as the Ag content increases, the band gap becomes smaller, which is beneficial to the utilization of visible light by the nanoparticles. When the mass fraction of silver nitrate is 10%, Eg drops to 2.79eV, indicating that it can absorb light with a wavelength of less than 444nm, and its ability to utilize visible light is greatly increased. In addition, due to the conductivity of Ag, the recombination of electrons and holes is reduced, the band gap width of the material is reduced, and the light response area is widened, which is more conducive to the utilization of sunlight and the generation of photogenerated carriers, thereby improving the photocatalytic activity.

[0086] (3) Antioxidant capacity test

[0087] The nanomaterials prepared in Examples 1, 3, 4 and Comparative Examples 1 and 2 were subjected to a DPPH free radical scavenging method to determine their DPPH free radical scavenging ability, i.e., antioxidant capacity. The results are shown in FIG. Figure 7 .

[0088] from Figure 7 It can be seen that the addition of chestnut tannin extract in Comparative Example 2 enhances the antioxidant capacity of the material compared to Comparative Example 1. Furthermore, in Examples 1, 3, and 4, antioxidant capacity increases with increasing silver content. A high antioxidant capacity is achieved when the silver nitrate mass fraction reaches 6%, while no significant increase is observed when the silver nitrate mass fraction reaches 10%.

[0089] (IV) Antibacterial performance test

[0090] The particle size of the nanomaterials prepared in Examples 1, 3, 4 and Comparative Examples 1 and 2 was measured using a dynamic light scattering method. The results are as follows: Figure 8 .

[0091] from Figure 8 It can be seen that titanium dioxide nanoparticles can aggregate into aggregates of about 200 nm. Compared with Comparative Example 1, the size distribution of nanoparticles in Comparative Example 2 becomes wider with the addition of chestnut wood extract template. This is because under heating conditions, chestnut wood extract undergoes hydrolysis reaction, which broadens the molecular weight distribution. In Examples 1, 3, and 4, the addition of silver effectively improves this situation because Ag + It is easier to reduce into nano-Ag particles and become the nucleus for the growth of titanium dioxide crystals. + With the increase of the content, the number of crystal nuclei increases, and the amount of n-butyl titanate participating in the reaction on each crystal nucleus decreases, which reduces the grain size.

[0092] The nanomaterials prepared in Examples 1, 3, 4 and Comparative Example 2 were tested for their antibacterial properties using the inhibition zone observation method. The test results are as follows: Figure 9 .

[0093] from Figure 9 It can be seen that the silver-titanium dioxide nanocomposites prepared in Examples 1, 3, and 4 have antibacterial activity against two typical bacteria, Staphylococcus aureus and Escherichia coli. When the mass fraction of silver nitrate is 10%, the sizes of the inhibition zones against the two bacteria are 8.2 mm and 6.4 mm, respectively.

[0094] Combine Figure 8 、 9Analysis shows that the key mechanism by which silver-titanium dioxide nanocomposites exert their antimicrobial activity is through the release of silver ions, which can directly kill bacterial cells through contact or indirectly through interaction with protein sulfhydryl groups, thereby damaging DNA and killing bacterial cells. The rate of silver release is proportional to the particle's surface area. As nanoparticle size decreases, the surface area increases, resulting in smaller nanoparticles with faster release rates and improved antimicrobial properties. By adjusting the size and morphology of the nanoparticles, their antimicrobial activity can be controlled.

[0095] Based on the above comprehensive evaluation, Example 4 is the optimal example.

[0096] Example 5

[0097] The application of silver-titanium dioxide nanocomposite materials in the protection of leather cultural relics is as follows:

[0098] The silver-titanium dioxide nanocomposite prepared in Example 1 was ultrasonically dispersed in water, wherein the weight ratio of the silver-titanium dioxide nanocomposite to water was 1:2500, to obtain a dispersed solution, which was then sprayed on the surface of the leather artifact.

[0099] (V) Comparison of leather before and after treatment

[0100] The surface color difference and antibacterial ability of leather before and after treatment were compared. The comparison results are as follows: Figure 10 .

[0101] Depend on Figure 10 It can be seen that after the dispersion was sprayed on the surface of the leather artifact, the color difference value of the leather artifact surface did not change significantly. Through antibacterial performance testing, it was found that the leather sprayed with the dispersion showed a more obvious inhibition zone, indicating that the color difference of the leather surface did not change significantly after the silver-titanium dioxide nanocomposite was treated, and it has a significant antibacterial effect.

[0102] The above describes a preferred embodiment of the present invention, but it should be understood that the invention is not limited to the contents disclosed herein. As long as non-substantial improvements are made using the method concepts and technical solutions of the present invention, or the method concepts and technical solutions of the present invention are applied to other occasions, they are all within the scope of protection of the present invention.

Claims

1. A method for preparing a silver-titanium dioxide nanocomposite material, characterized in that: The steps include: (1) mixing a silver nitrate solution with a chestnut tannin solution to obtain a silver nitrate-chestnut tannin solution; the mass fraction of chestnut tannin in the chestnut tannin solution is 5% to 15%; (2) dissolving n-butyl titanate in anhydrous ethanol to obtain an n-butyl titanate solution, adding the n-butyl titanate solution to the silver nitrate-chestnut extract solution and mixing them uniformly to obtain a mixed solution; (3) The mixed solution is subjected to a hydrothermal reaction. After the reaction is completed, the mixed solution is centrifuged, washed, dried, and calcined to obtain a silver-titanium dioxide nanocomposite material.

2. The method for preparing the silver-titanium dioxide nanocomposite material according to claim 1, wherein: The mass fraction of silver nitrate in the silver nitrate solution of step (1) is 1% to 10%; the weight ratio of the silver nitrate solution to the chestnut tannin solution is (0.5 to 5.0):1.

0.

3. The method for preparing the silver-titanium dioxide nanocomposite material according to claim 1, wherein: The weight ratio of n-butyl titanate to anhydrous ethanol in step (2) is 1:(10-30).

4. The method for preparing the silver-titanium dioxide nanocomposite material according to claim 3, wherein: The weight ratio of the n-butyl titanate solution to the silver nitrate-chestnut tannin solution is (10-30):

1.

5. The method for preparing the silver-titanium dioxide nanocomposite material according to claim 1, wherein: The hydrothermal reaction temperature in step (3) is 120-160° C., and the reaction time is 2-6 hours.

6. The method for preparing the silver-titanium dioxide nanocomposite material according to claim 5, wherein: The calcination temperature is 300-800°C and the time is 1-5 hours.

7. The silver-titanium dioxide nanocomposite material prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the silver-titanium dioxide nanocomposite material as claimed in claim 7 in the protection of leather cultural relics.

9. The use of the silver-titanium dioxide nanocomposite material in leather cultural relic protection as claimed in claim 8, characterized in that: The application method comprises the following steps: ultrasonically dispersing the silver-titanium dioxide nanocomposite material in water to obtain a dispersed solution, and spraying or immersing the dispersed solution on the surface of the leather cultural relic.

10. Use of the silver-titanium dioxide nanocomposite material in leather cultural relic protection according to claim 9, characterized in that: The weight ratio of the silver-titanium dioxide nanocomposite material to water is 1:(1000-4000).

Images