A template-free method for preparing chitosan-inorganic SiO2 nanofiber aerogel, a preparation method and application thereof
By introducing chitosan into SiO2 nanofiber aerogel, chitosan@inorganic SiO2 nanofiber aerogel was prepared, which solved the problem of insufficient antibacterial properties of existing SiO2 nanofiber aerogels and achieved efficient and safe water purification effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 新疆理工学院
- Filing Date
- 2023-05-26
- Publication Date
- 2026-05-19
AI Technical Summary
Existing SiO2 nanofiber aerogel materials have shortcomings in terms of antibacterial properties and environmental friendliness. Long-term use with heavy metal ion loading may cause harm to the human body, and the antibacterial performance is not significant or durable enough.
Chitosan active component was introduced into SiO2 nanofiber aerogel, and chitosan@inorganic SiO2 nanofiber aerogel was prepared by electrospinning and freeze-drying. The antibacterial properties were improved by utilizing the biocompatibility and degradability of chitosan.
The prepared chitosan@inorganic SiO2 nanofiber aerogel exhibits significant antibacterial effects, with broad-spectrum antibacterial activity, long-lasting effect, and no heavy metal ions added, making it safe and environmentally friendly, and suitable for water purification.
Smart Images
Figure CN116651406B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of inorganic silicon wastewater treatment technology, and in particular to a template-free chitosan@inorganic SiO2 nanofiber aerogel, its preparation method, and its application. Background Technology
[0002] With the rapid development of society, people's desire for a healthy life and their awareness of safety are becoming increasingly strong. Because water is a solvent with strong dissolving power and is in extensive contact with the external environment such as air and soil, it inevitably contains many impurities. The essence of water purification is to remove these impurities from the water through various technologies, thereby obtaining pure water that meets water quality standards for drinking.
[0003] In the research of SiO2 nanofiber antibacterial aerogels, SiO2 nanofiber aerogels are a novel type of structurally controllable porous material with many unique properties, such as low refractive index, low thermal conductivity, low acoustic impedance, low elastic modulus, strong adsorption, and typical fractal structure. They can be fabricated into various high-performance materials such as acoustic impedance coupling materials, filter materials, and high-temperature insulation materials. Adsorption is currently the most effective and cost-efficient method, so finding economical and efficient new adsorption materials is a research hotspot now and for a long time to come. SiO2 nanofiber aerogels have abundant hydroxyl functional groups, making them easy to modify. Furthermore, their morphology is controllable during preparation, and they are non-toxic, odorless, and pollution-free. Therefore, the activity and antibacterial properties of SiO2 nanofiber aerogel materials impregnated with antibacterial agents are far superior to those of conventional antibacterial agents. For example, invention patent CN114097822A discloses a polyurethane foam-reinforced silver-loaded gel antibacterial material, its preparation method, and its application, which has a broad-spectrum bactericidal effect. However, the loaded silver ions are heavy metal ions, and long-term use can cause harm to the human body.
[0004] Therefore, the research has yielded a SiO2 nanofiber aerogel material for water purification with excellent and long-lasting antibacterial activity and is environmentally friendly. This is of great significance. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of existing technologies by providing a template-free chitosan@inorganic SiO2 nanofiber aerogel, its preparation method, and its applications. This invention adds chitosan (CS) as an active component to the aerogel. The chitosan@inorganic SiO2 electrospun antibacterial nanofiber aerogel possesses both biocompatibility and biodegradability, exhibiting more significant and durable antibacterial properties compared to pure SiO2 nanofiber aerogel materials.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0007] This invention provides a template-free method for preparing chitosan@inorganic SiO2 nanofiber aerogel, comprising the following steps:
[0008] 1) Tetraethyl orthosilicate, dilute hydrochloric acid, ethanol and water are mixed to obtain SiO2 sol. The SiO2 sol is electrospun to obtain SiO2 nanofibers.
[0009] 2) SiO2 nanofibers were impregnated in a chitosan solution to obtain chitosan@SiO2 nanofibers;
[0010] 3) Chitosan@SiO2 nanofibers were freeze-dried to obtain chitosan@inorganicSiO2 nanofiber aerogel.
[0011] Preferably, the mass ratio of tetraethyl orthosilicate, dilute hydrochloric acid, ethanol and water in step 1) is 60-80:6-8:20-27:12-20; the mass fraction of the dilute hydrochloric acid is 0.8-1.2%; and the ethanol is anhydrous ethanol.
[0012] Preferably, the mixing temperature in step 1) is 60–90°C, the mixing time is 30–60 min, and the mixing speed is 400–500 rpm.
[0013] Preferably, in the electrospinning process described in step 1), the positive electrode voltage is 15–25 kV, the working distance is 12–18 cm, and the flow rate of the SiO2 sol is 1.5–2.5 mL / h.
[0014] Preferably, the mass ratio of the chitosan solution in step 2) to the tetraethyl orthosilicate in step 1) is 5-10:60-80.
[0015] Preferably, in step 2), the degree of deacetylation of chitosan is ≥95%, the viscosity of chitosan is 100-200 mPa·s, the molecular weight of chitosan is 50-90 kDa, the mass concentration of chitosan solution is 10-25%, and the solvent in chitosan solution is hydrochloric acid with a mass fraction of 10-20%.
[0016] Preferably, the temperature of the freeze-vacuum drying in step 3) is -80 to -60°C, the time of freeze-vacuum drying is 20 to 28 hours, and the vacuum degree of freeze-vacuum drying is 1 to 10 Pa.
[0017] The present invention also provides chitosan@inorganic SiO2 nanofiber aerogel prepared by the preparation method described above.
[0018] The present invention also provides the application of the chitosan@inorganic SiO2 nanofiber aerogel in water purification.
[0019] The beneficial effects of this invention include:
[0020] 1) The chitosan@inorganic SiO2 electrospun antibacterial nanofiber aerogel of the present invention for water purification has three antibacterial effects: adsorption, complexation, and contact. It is significantly better than the antibacterial effect of simple adsorption or contact antibacterial materials. No metal ions are added during the synthesis process, making the experimental process safe and reliable. Chitosan@SiO2 nanofiber aerogel is a green and environmentally friendly antibacterial material for water purification.
[0021] 2) The surface of the chitosan@inorganic SiO2 nanofiber aerogel of the present invention has certain properties of complexing metal cations and hydrophilicity, which can fully contact bacteria in water and generate a certain adsorption effect on the negatively charged groups on the surface of bacterial cells. The high molecular weight CS endows the SiO2 nanofibers with efficient and stable antibacterial activity and antibacterial adhesion, ensuring that the antibacterial performance of SiO2 nanofibers is more long-lasting and durable. It has excellent inhibitory and killing effects on common pathogenic bacteria such as Escherichia coli and Staphylococcus aureus, and has a broad-spectrum antibacterial effect.
[0022] 3) High molecular weight CS has good biocompatibility and antibacterial properties. It can change the activity of bacterial cell membrane and surface ion exchange capacity through cell affinity, and has outstanding biological effects in antibacterial ability. It can effectively remove bacteria in water, reduce antibacterial side effects, and increase the durability of antibacterial effect. Attached Figure Description
[0023] Figure 1 This is a scanning electron microscope image of the chitosan@inorganic SiO2 nanofiber aerogel from Example 1;
[0024] Figure 2 The image shows the filtration performance of the chitosan@inorganic SiO2 nanofiber aerogel from Example 1.
[0025] Figure 3 The image shows the filtration performance of pure SiO2 nanofiber aerogel in Comparative Example 1. Detailed Implementation
[0026] This invention provides a template-free method for preparing chitosan@inorganic SiO2 nanofiber aerogel, comprising the following steps:
[0027] 1) Tetraethyl orthosilicate, dilute hydrochloric acid, ethanol and water are mixed to obtain SiO2 sol. The SiO2 sol is electrospun to obtain SiO2 nanofibers.
[0028] 2) SiO2 nanofibers were impregnated in a chitosan solution to obtain chitosan@SiO2 nanofibers;
[0029] 3) Chitosan@SiO2 nanofibers were freeze-dried to obtain chitosan@inorganicSiO2 nanofiber aerogel.
[0030] In this invention, the mass ratio of tetraethyl orthosilicate, dilute hydrochloric acid, ethanol, and water in step 1) is preferably 60-80:6-8:20-27:12-20, more preferably 65-75:6.5-7.5:22-26:14-18, and even more preferably 68-72:7:24-25:15-16; the mass fraction of the dilute hydrochloric acid is preferably 0.8-1.2%, more preferably 0.9-1.1%, and even more preferably 1%; the ethanol is preferably anhydrous ethanol.
[0031] In this invention, the mixing temperature in step 1) is preferably 60-90°C, more preferably 65-85°C, and even more preferably 70-80°C; the mixing time is preferably 30-60 min, more preferably 35-55 min, and even more preferably 40-50 min; the mixing speed is preferably 400-500 rpm, more preferably 420-480 rpm, and even more preferably 440-460 rpm.
[0032] In the electrospinning described in step 1) of this invention, the positive electrode voltage is preferably 15-25kV, more preferably 17-23kV, and even more preferably 19-21kV; the working distance is preferably 12-18cm, more preferably 14-16cm, and even more preferably 15cm; the flow rate of the SiO2 sol is preferably 1.5-2.5mL / h, more preferably 1.7-2.3mL / h, and even more preferably 1.9-2mL / h.
[0033] In this invention, the mass ratio of the chitosan (CS) solution in step 2) to the tetraethyl orthosilicate in step 1) is preferably 5-10:60-80, more preferably 6-9:65-75, and even more preferably 7-8:68-72.
[0034] In step 2) of the present invention, the degree of deacetylation of chitosan is preferably ≥95%, more preferably ≥96%, and more preferably ≥97%; the viscosity of chitosan is preferably 100-200 mPa·s, more preferably 120-180 mPa·s, and more preferably 140-160 mPa·s; the molecular weight of chitosan is preferably 50-90 kDa, more preferably 60-87 kDa, and more preferably 65-75 kDa; the mass concentration of chitosan solution is preferably 10-25%, more preferably 13-22%, and more preferably 15-20%; the solvent in chitosan solution is preferably hydrochloric acid with a mass fraction of 10-20%, and more preferably hydrochloric acid with a mass fraction of 13-15%.
[0035] In step 2) of this invention, during the impregnation process, stirring is performed to uniformly disperse the SiO2 nanofibers in the chitosan solution; the stirring rate is preferably 1800-2200 rpm, more preferably 1900-2100 rpm, and even more preferably 2000 rpm; the impregnation temperature is preferably 75-85℃, more preferably 78-82℃, and even more preferably 80℃; the impregnation time is preferably 2-4 h, and even more preferably 3 h; CS is loaded onto the SiO2 nanofibers through impregnation.
[0036] In this invention, the temperature of the freeze-drying in step 3) is preferably -80 to -60°C, more preferably -75 to -65°C, and even more preferably -72 to -68°C; the freeze-drying time is preferably 20 to 28 hours, more preferably 22 to 26 hours, and even more preferably 24 to 25 hours; the vacuum degree of the freeze-drying is preferably 1 to 10 Pa, more preferably 3 to 8 Pa, and even more preferably 5 to 6 Pa.
[0037] The present invention also provides chitosan@inorganic SiO2 nanofiber aerogel prepared by the preparation method described above.
[0038] The present invention also provides the application of the chitosan@inorganic SiO2 nanofiber aerogel in water purification.
[0039] In this invention, chitosan@inorganic SiO2 nanofiber aerogel is used to replace PP cotton in ceramic filter material.
[0040] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0041] Example 1
[0042] A SiO2 sol was obtained by mixing 63 parts by weight of tetraethyl orthosilicate, 6 parts by weight of dilute hydrochloric acid (1% by weight), 24 parts by weight of anhydrous ethanol, and 14 parts by weight of water at 80°C and 450 rpm for 45 min. The SiO2 sol was cooled to room temperature and then electrospun at a positive electrode voltage of 20 kV, a working distance of 15 cm, and a flow rate of 2 mL / h. After electrospinning, the sol was dried to obtain SiO2 nanofibers.
[0043] Chitosan (degree of deacetylation 96%, viscosity 150 mPa·s, molecular weight 57 kDa) was dissolved in 17% hydrochloric acid to obtain a 20% chitosan solution. SiO2 nanofibers were impregnated in 8 parts by weight of the chitosan solution at 80°C. During impregnation, the solution was stirred at 2000 rpm to ensure uniform dispersion of the SiO2 nanofibers. Impregnation for 3 hours yielded chitosan@SiO2 nanofibers.
[0044] Chitosan@SiO2 nanofibers were transferred into a mold and freeze-dried at -70℃ and 5Pa for 24 hours to obtain chitosan@inorganicSiO2 nanofiber aerogel.
[0045] The scanning electron microscope image of the chitosan@inorganic SiO2 nanofiber aerogel in Example 1 is shown below. Figure 1 As shown. By Figure 1 It is evident that the chitosan@inorganic SiO2 nanofiber aerogel retains its fibrous shape and original fiber morphology; however, some fibers were broken during the stirring process to form the aerogel.
[0046] Comparative Example 1
[0047] The chitosan (CS) solution in Example 1 was omitted to prepare pure SiO2 nanofiber aerogel without the addition of CS. The other steps were the same as in Example 1.
[0048] The filtration performance of the chitosan@inorganic SiO2 nanofiber aerogel of Example 1 and the pure SiO2 nanofiber aerogel of Comparative Example 1 was tested. The chitosan@inorganic SiO2 nanofiber aerogel and the pure SiO2 nanofiber aerogel were placed in funnels (the thickness of the aerogel in the funnel was 1.5 cm). Two equal portions of sand of the same properties were divided and placed in two beakers. 400 mL of distilled water and 5 g of sand (mainly composed of dust, pebbles, and straw) were added to each beaker, and the mixture was stirred thoroughly. The mixture was then poured into the two funnels, with conical flasks attached to the bottom of each funnel. The state of the water after filtration was observed. The states of the water after filtration from the chitosan@inorganic SiO2 nanofiber aerogel of Example 1 and the pure SiO2 nanofiber aerogel of Comparative Example 1 are shown below. Figure 2 and Figure 3 As shown. By Figure 2 and Figure 3 It can be seen that the water filtered by the chitosan@inorganic SiO2 nanofiber aerogel in Example 1 is clear and transparent, without turbidity or large particulate impurities.
[0049] The antibacterial properties of the chitosan@inorganic SiO2 nanofiber aerogel of Example 1 and the pure SiO2 nanofiber aerogel of Comparative Example 1 were tested. 1 g each of the chitosan@inorganic SiO2 nanofiber aerogel of Example 1 and the pure SiO2 nanofiber aerogel of Comparative Example 1 were co-cultured with 10 mL of bacterial suspension in an incubator at 37°C and a shaking speed of 150 rpm for 24 h. The culture solution was then spread onto nutrient agar medium and incubated at 37°C for 24 h. Colony growth was observed, and the antibacterial rate of the aerogel was calculated using the plate count method. The antibacterial rates of the pure SiO2 nanofiber aerogel of Comparative Example 1 against *Escherichia coli* and *Staphylococcus aureus* were 2.0% and 3.5%, respectively. The antibacterial rates of the chitosan@inorganic SiO2 nanofiber aerogel of Example 1 against *Escherichia coli* and *Staphylococcus aureus* were 98% and 99%, respectively. The chitosan@inorganic SiO2 nanofiber aerogel of Example 1 exhibits excellent antibacterial rates against Escherichia coli and Staphylococcus aureus, and also demonstrates excellent broad-spectrum antibacterial activity.
[0050] Example 2
[0051] A SiO2 sol was obtained by mixing 78 parts by weight of tetraethyl orthosilicate, 8 parts by weight of dilute hydrochloric acid (0.9% by weight), 27 parts by weight of anhydrous ethanol, and 18 parts by weight of water at 65°C and 420 rpm for 55 min. The SiO2 sol was cooled to room temperature and then electrospun at a positive electrode voltage of 16 kV, a working distance of 13 cm, and a flow rate of 1.6 mL / h. After electrospinning, the sol was dried to obtain SiO2 nanofibers.
[0052] Chitosan (degree of deacetylation 95%, viscosity 130 mPa·s, molecular weight 66 kDa) was dissolved in 15% hydrochloric acid to obtain a chitosan solution with a mass concentration of 18%. SiO2 nanofibers were impregnated in 6 parts by mass of the chitosan solution at 76°C. During impregnation, the solution was stirred at 1900 rpm to ensure uniform dispersion of the SiO2 nanofibers. Impregnation for 3.5 h yielded chitosan@SiO2 nanofibers.
[0053] Chitosan@SiO2 nanofibers were transferred into a mold and freeze-dried at -75°C and 2 Pa for 22 h to obtain chitosan@inorganic SiO2 nanofiber aerogel.
[0054] The antibacterial properties of the chitosan@inorganic SiO2 nanofiber aerogel in Example 2 were tested using the same antibacterial test method as in Example 1. The chitosan@inorganic SiO2 nanofiber aerogel in Example 2 showed antibacterial rates of 98.5% and 99% against Escherichia coli and Staphylococcus aureus, respectively, demonstrating excellent broad-spectrum antibacterial activity.
[0055] Example 3
[0056] A SiO2 sol was obtained by stirring 70 parts by weight of tetraethyl orthosilicate, 7 parts by weight of dilute hydrochloric acid (1.1% by weight), 21 parts by weight of anhydrous ethanol, and 16 parts by weight of water at 75°C and 480 rpm for 35 min. The SiO2 sol was cooled to room temperature and then electrospun at a positive electrode voltage of 23 kV, a working distance of 17 cm, and a flow rate of 2.2 mL / h. After electrospinning, the sol was dried to obtain SiO2 nanofibers.
[0057] Chitosan (degree of deacetylation 96.5%, viscosity 180 mPa·s, molecular weight 88 kDa) was dissolved in 13% hydrochloric acid to obtain a 15% chitosan solution. SiO2 nanofibers were impregnated in 10 parts by weight of the chitosan solution at 83°C. During impregnation, the solution was stirred at 2100 rpm to ensure uniform dispersion of the SiO2 nanofibers. Impregnation for 2.5 h yielded chitosan@SiO2 nanofibers.
[0058] Chitosan@SiO2 nanofibers were transferred into a mold and freeze-dried at -65℃ and 8 Pa for 26 h to obtain chitosan@inorganic SiO2 nanofiber aerogel.
[0059] The antibacterial properties of the chitosan@inorganic SiO2 nanofiber aerogel in Example 3 were tested using the same antibacterial test method as in Example 1. The chitosan@inorganic SiO2 nanofiber aerogel in Example 3 showed antibacterial rates of 98.5% and 99.2% against Escherichia coli and Staphylococcus aureus, respectively, demonstrating excellent broad-spectrum antibacterial activity.
[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. An application of template-free chitosan@inorganic SiO2 nanofiber aerogel in water purification, characterized in that, Template-free chitosan@inorganic SiO2 nanofiber aerogel exhibits three antibacterial effects: adsorption, complexation, and contact, which are superior to the antibacterial effects of simple adsorption or contact antibacterial materials. The template-free method for preparing chitosan@inorganic SiO2 nanofiber aerogel includes the following steps: 1) Tetraethyl orthosilicate, dilute hydrochloric acid, ethanol and water are mixed to obtain SiO2 sol. The SiO2 sol is electrospun to obtain SiO2 nanofibers. 2) SiO2 nanofibers were impregnated in a chitosan solution to obtain chitosan@SiO2 nanofibers; 3) Chitosan@SiO2 nanofibers were freeze-dried to obtain chitosan@inorganicSiO2 nanofiber aerogel; The solvent in the chitosan solution is hydrochloric acid with a mass fraction of 10-20%.
2. The application according to claim 1, characterized in that, In step 1), the mass ratio of tetraethyl orthosilicate, dilute hydrochloric acid, ethanol, and water is 60~80:6~8:20~27:12~20; the mass fraction of the dilute hydrochloric acid is 0.8~1.2%, and the ethanol is anhydrous ethanol.
3. The application according to claim 1 or 2, characterized in that, Step 1) The mixing temperature is 60~90℃, the mixing time is 30~60min, and the mixing speed is 400~500rpm.
4. The application according to claim 3, characterized in that, In step 1), the positive electrode voltage is 15~25kV, the working distance is 12~18cm, and the flow rate of SiO2 sol is 1.5~2.5mL / h.
5. The application according to claim 4, characterized in that, The mass ratio of the chitosan solution in step 2) to the tetraethyl orthosilicate in step 1) is 5~10:60~80.
6. The application according to claim 5, characterized in that, In step 2), the degree of deacetylation of chitosan is ≥95%, the viscosity of chitosan is 100~200 mPa·s, the molecular weight of chitosan is 50~90 kDa, and the mass concentration of chitosan solution is 10~25%.
7. The application according to claim 5 or 6, characterized in that, Step 3) The temperature of the freeze-vacuum drying is -80~-60℃, the time of the freeze-vacuum drying is 20~28h, and the vacuum degree of the freeze-vacuum drying is 1~10Pa.