Silk fibroin-based iron tannate coating composite aerogel as well as preparation method and application thereof
By uniformly distributing tanninic acid-ferrous ion complex nanoparticles on the inner wall of the fibroin-based aerogel channel, the ferrous iron-coated composite aerogel is formed, which solves the biological fouling problem caused by microbial growth and achieves stable and efficient water evaporation and photothermal performance.
Patent Information
- Application Number
- CN202510545567.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-28
- Publication Date
- 2025-08-01
AI Technical Summary
The growth and reproduction of microorganisms in the silk fibroin-based three-dimensional evaporator material can easily lead to biological fouling, blocking pores, and affecting photothermal performance and evaporation rate.
Complex nanoparticles formed by tannin-ferrous ions are uniformly distributed on the inner wall of the pores of the silk fibroin-based aerogel to form a silk fibroin-based tannin-coated composite aerogel, combining with nanoenzyme catalytic properties to inhibit microbial growth.
It realizes a stable porous structure of aerogel, keeps the water evaporation channel unobstructed, improves photothermal performance, suppresses biological pollution for a long time, and maintains efficient water evaporation performance. It is suitable for complex water environments.
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Figure CN120399460A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of nanocomposites, and particularly relates to a silk fibroin-based tannic acid iron-coated composite aerogel, a preparation method thereof, and an application thereof. Background Art
[0002] Solar-driven interfacial evaporation technology has shown broad application prospects in solving the global freshwater shortage problem due to its clean and efficient characteristics. This process localizes heat at the evaporation interface to improve the water evaporation efficiency. Silk fibroin, as a natural polymer material, has good biocompatibility, adjustable mechanical properties, and degradability, and has high-efficiency photothermal conversion and water evaporation acceleration properties, making it a research hotspot for solar-driven interfacial water evaporation materials. However, due to the good biocompatibility of silk fibroin, microorganisms widely distributed in natural water bodies and sewage environments are likely to aggregate on the surface and internal pores of the evaporator, thus forming biofouling. Blocking the water delivery channels inside the evaporator and reducing the light absorption performance of the evaporator, resulting in a significant reduction in the evaporation rate and seriously affecting the application of the material.
[0003] Complexes formed by tannic acid and iron ions have received extensive attention in recent years due to their excellent photothermal conversion performance. Moreover, some iron-based materials such as iron oxides have nanozyme activity and can catalyze the production of reactive oxygen species for antibacterial purposes. Therefore, by synergistically integrating them with silk fibroin, a composite aerogel with a stable porous structure, high-efficiency photothermal conversion, and long-term anti-biofouling performance can be constructed, and a new anti-biofouling solar evaporation material that takes into account light absorption and microbial inhibition can be developed to achieve the unity of high-efficiency solar absorption, rapid water transport, and long-term antibacterial functions.
[0004] In view of the above defects, the creator of the present invention finally obtained the present invention through long-term research and practice. Summary of the Invention
[0005] The purpose of the present invention is to solve the problem that the growth and reproduction of microorganisms inside the silk fibroin-based three-dimensional evaporator material are likely to lead to the formation of biofouling, resulting in blocked pores and loss of photothermal performance, thus affecting the normal use of the material, and provides a silk fibroin-based tannic acid iron-coated composite aerogel, a preparation method thereof, and an application thereof.
[0006] To achieve the above purpose, the present invention discloses a silk fibroin-based tannic acid iron-coated composite aerogel, which includes a plant polyphenol coating and complex nanoparticles formed by tannic acid and iron ions, and the nanoparticles are uniformly distributed on the inner wall of the pore channels of the silk fibroin-based aerogel oriented pore structure.
[0007] The present invention also discloses a preparation method of the above silk fibroin-based tannic acid iron-coated composite aerogel, which includes the following steps:
[0008] S1. Pour the silk fibroin solution into a polystyrene mold, freeze it using the freeze-casting method, and place the mold on a copper plate pre-cooled with liquid nitrogen. Control the amount of liquid nitrogen added to keep the temperature constant at -20°C. After half an hour, put it into a freeze dryer and freeze-dry for 48 h to obtain a silk fibroin aerogel with an oriented structure.
[0009] S2. Immerse the silk fibroin-based aerogel obtained in step S1 in a methanol solution for fixation and washing, then freeze it, and finally freeze-dry it to obtain a silk fibroin-based aerogel treated by hydrophobic treatment.
[0010] S3. Immerse the silk fibroin-based aerogel obtained in step S2 in a mixed solution of tannic acid-Tris solution and APTES solution, fully soak and adsorb tannic acid molecules, and alternately wash the excess tannic acid on the surface with deionized water and ethanol to obtain a silk fibroin-based tannic acid composite aerogel.
[0011] S4. Immerse the silk fibroin-based tannic acid composite aerogel obtained in step S3 in an iron sulfate solution to form a tannic acid-iron ion complex on the surface of the aerogel, then wash the excess solution on the surface of the aerogel with deionized water, and then freeze-dry the aerogel to obtain a silk fibroin-based tannic acid iron-coated composite aerogel.
[0012] In the above step S1, the freeze-casting method is carried out using liquid nitrogen.
[0013] In the above step S3, the volume ratio of the tannic acid-Tris solution to the APTES solution is 5:1.
[0014] In the above step S3, the concentration of tannic acid in the tannic acid-Tris solution is 0.2 wt%, and the concentration of APTES solution is 1 wt%.
[0015] In the above step S4, the iron content in the iron sulfate solution is 0.2 - 0.8 wt%.
[0016] The present invention also discloses the application of the above silk fibroin-based tannic acid iron-coated composite aerogel in interfacial solar-driven photo-thermal water treatment.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The silk fibroin-based tannic acid iron-coated composite aerogel prepared by the present invention has a stable structure and good water evaporation performance. The vertically oriented pore structure of the aerogel is conducive to water transmission and ensures continuous and efficient water evaporation. Nanozymes are a new type of mimetic enzyme, which are more similar to the structure of the catalytic active center of natural enzymes. Their catalytic mechanism is mediated by nanostructures composed of specific atoms, different from traditional small molecule mimetic enzymes and chemical catalysts. The catalytic reaction of nanozymes is located on the surface of nanomaterials. At the same time, nanozymes have selective binding to substrates, possess catalytic mechanisms and reaction kinetics similar to those of natural enzymes, and have important development prospects in catalytic sterilization, virus inactivation, and toxin degradation. In-situ growth of tannic acid iron nanozyme coating on the surface of silk fibroin-based porous aerogel provides the aerogel with excellent anti-fouling performance and improves the photothermal performance of the aerogel. Compared with silk fibroin-based aerogel, the silk fibroin-based tannic acid iron-coated composite aerogel has better water evaporation performance. At the same time, the silk fibroin-based tannic acid iron-coated composite aerogel has a significant effect in inhibiting biological fouling, which can keep the pores of the aerogel unobstructed and prevent fouling by microorganisms such as Escherichia coli and Staphylococcus aureus, enabling the water evaporation rate to maintain long-term stability. In addition, it has cyclic stability during the evaporation process in high-concentration brine and simulated seawater, and is also applicable to complex actual outdoor evaporation scenarios; BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 Scanning pictures of silk fibroin-based tannic acid iron-coated composite aerogels with different TA contents, (a) 0.1 wt%, (b) 0.2 wt%, (c) 0.4 wt%, (d) 0.8 wt%;
[0019] Figure 2 Scanning pictures of silk fibroin-based aerogel and silk fibroin-based tannic acid iron-coated composite aerogel, where (a-c) are the physical pictures and pore SEM pictures of silk fibroin aerogel, and (d-f) are the physical pictures and pore SEM pictures of silk fibroin-based tannic acid iron-coated composite aerogel;
[0020] Figure 3 Element distribution map of the surface of silk fibroin-based tannic acid iron-coated composite aerogel;
[0021] Figure 4 XPS spectrum of silk fibroin-based tannic acid iron-coated composite aerogel;
[0022] Figure 5 Infrared spectrum of silk fibroin-based tannic acid iron-coated composite aerogel;
[0023] Figure 6Among them, (a) shows the OD values after culturing Escherichia coli suspensions at different pH values, (b) shows the OD values after culturing Staphylococcus aureus suspensions at different pH values, and (c) shows the color development results of the TMB experiment and the light absorption spectra of the solutions;
[0024] Figure 7 Among them, (a) shows the OD values after culturing Escherichia coli suspensions at different H2O2 concentrations, (b) shows the OD values after culturing Staphylococcus aureus suspensions at different H2O2 concentrations, and (c) shows the color development results of the TMB experiment and the light absorption spectra of the solutions at different H2O2 concentrations;
[0025] Figure 8 shows the effect of iron concentration on the catalytic performance of tannic acid iron-coated silk fibroin-based composite aerogel (TA-Fe 3+ @SF) nanozyme: Photos of color development solutions and light absorption spectra with (a) TMB, (b) OPD, and (c) ABTS as different substrates
[0026] Figure 9 is the photothermal heating data graph of tannic acid iron-coated silk fibroin-based composite aerogels with different iron contents irradiated under 1 sun intensity for 50 min;
[0027] Figure 10 Among them, (a) shows the mass change per unit area of TA-Fe 3+ @SF aerogel accelerating water evaporation under 1 sun irradiation, and (b) shows the evaporation rate of TA-Fe 3+ @SF aerogel accelerating water evaporation under 1 sun irradiation;
[0028] Figure 11 are the antibacterial zone photos of tannic acid iron-coated silk fibroin-based composite aerogel against Escherichia coli and Staphylococcus aureus;
[0029] Figure 12 are the antibacterial zone diameters of tannic acid iron-coated silk fibroin-based composite aerogel against Escherichia coli and Staphylococcus aureus;
[0030] Figure 13 is the water evaporation performance and retention rate graph of tannic acid iron-coated silk fibroin-based composite aerogel with or without added H2O2 after co-culturing with bacterial solution for 5 days;
[0031] Figure 14 is the water evaporation capacity graph of tannic acid iron-coated silk fibroin-based composite aerogel evaporating cyclically in high-concentration saline water for 10 h;
[0032] Figure 15 is the water evaporation capacity graph of tannic acid iron-coated silk fibroin-based composite aerogel under 1 sun intensity after the aerogel continuously undergoes 20 evaporation cycles;
[0033] Figure 16 The image of the metal ion concentration for collecting condensed water after simulating seawater evaporation;
[0034] Figure 17 The variation diagrams of temperature, light intensity, and evaporation rate within 10 h of evaporation of the silk fibroin-based tannic acid iron coating composite aerogel under actual outdoor sunlight. Specific implementation manners
[0035] The following further elaborates on the above and additional technical features and advantages of the present invention in conjunction with the accompanying drawings.
[0036] Example 1
[0037] This example prepares a silk fibroin-based aerogel, and the specific steps are as follows:
[0038] (1) Cut the silkworm cocoons into pieces and boil them in an aqueous solution of 0.02 M Na2CO3 for 30 min, rinse with excessive deionized water, and then place the degummed silk in an oven for drying.
[0039] (2) Then dissolve the degummed silk fibers in a 9.3 M lithium bromide solution and dissolve them in a water bath at 60 °C for 4 h.
[0040] (3) After the dissolution, pour the obtained solution into a dialysis bag for dialysis. Keep changing the water frequency during the process, the dialysis time is 72 h, and collect by centrifugation after the end.
[0041] (4) Configure the above silk fibroin solution to a concentration of 40 wt%.
[0042] (5) Prepare by the method of directional freezing casting, pour the mixture into a cylindrical mold on a cold plate, and pour liquid nitrogen to control the temperature.
[0043] Example 2
[0044] This example prepares tannic acid-aminopropyltriethoxysilane (TA-APTES) solutions with different TA contents, and the specific steps are as follows:
[0045] (1) Weigh 0.1, 0.2, 0.4, and 0.8 g of tannic acid and dissolve them in 100 mL of Tris-HCl buffer solution (pH = 8.5) respectively.
[0046] (2) Weigh 0.2 g of APTES and dissolve it in 20 mL of absolute ethanol.
[0047] (3) Then mix each group of TA-Tris solutions with the APTES solution evenly to prepare tannic acid APTES solutions with different TA contents.
[0048] Example 3
[0049] In this example, a silk fibroin-based iron tannate-coated composite aerogel was prepared, and the specific steps are as follows:
[0050] The silk fibroin-based aerogel was placed in a TA-APTES solution with different TA contents prepared, and the aerogel was gently squeezed to make the aerogel adsorb as much tannic acid solution as possible.
[0051] After the adsorption was completed, the excess TA-APTES solution was washed away with deionized water, and silk fibroin-based tannic acid composite aerogels with different TA contents were obtained after freeze-drying.
[0052] Example 4
[0053] In this example, silk fibroin-based iron tannate-coated composite aerogels with different iron contents were prepared, and the specific steps are as follows:
[0054] Ferric sulfate solutions with iron contents of 0, 0.2, 0.4, and 0.8 wt% were prepared. The silk fibroin-based tannic acid composite aerogel prepared with a TA content of 0.2 wt% was immersed in each of them, and the solution was shaken to make the iron ions and tannic acid on the surface of the aerogel coordinate evenly. It was left for 12 h to complete the coordination.
[0055] The excess ferric sulfate solution was washed away, and a silk fibroin-based iron tannate-coated composite aerogel was obtained after freeze-drying.
[0056] Example 5
[0057] This example was to test the effects of environmental factors (pH, hydrogen peroxide concentration) on the enzyme activity of the silk fibroin-based iron tannate-coated composite aerogel (wherein, the aerogel was prepared by the process with a TA content of 0.2 wt% and an iron concentration of 0.4 wt%), and the specific steps are as follows:
[0058] 0.2 mM glacial acetic acid and 0.2 mM anhydrous sodium acetate solution were mixed in different proportions, and buffer solutions with different pH values (3, 4, 5, 5.5, 6, 7) were prepared under the measurement of a pH meter. At room temperature, H2O2 (concentration of 0.2 mM) and TMB (5 mM) were added to a reaction system with a volume of 3 mL. Then, the TA-Fe 3+ @SF aerogel with a length of 1.2 cm was added to the prepared reaction solution, and it was reacted in the dark for 5 min under different pH conditions. Subsequently, the solutions after each group of reactions were taken for ultraviolet absorption tests, and the absorption peaks at 652 nm were recorded and compared.
[0059] To a 3 mL reaction system with a TMB concentration of 5 mM and a pH of 5.5, different contents of H2O2 were added to make the concentration of H2O2 in the system 0.1, 0.2, 0.3, 0.4, and 0.5 mM respectively. The TA-Fe with a length of 1.2 cm3+ The @SF aerogel was added to the prepared reaction solution, and the reaction was carried out in the dark for 5 min under the conditions of different H2O2 concentrations. Subsequently, the solutions after the reaction of each group were taken for ultraviolet absorption test, and the absorption peaks at 652 nm were recorded and compared.
[0060] In the attached drawings, the silk fibroin-based iron tannate-coated composite aerogels prepared with ferric sulfate concentrations of 0, 0.2, 0.4, and 0.8 wt% are named TA-Fe 3+ @SF-1, TA-Fe 3+ @SF-2, TA-Fe 3+ @SF-3, TA-Fe 3+ @SF-4.
[0061] Figure 1 This is the scanning electron microscope photograph of the silk fibroin-based iron tannate-coated composite aerogel prepared with a ferric sulfate concentration of 0.4 wt% and TA concentrations of 0.1, 0.2, 0.4, and 0.8 wt% in this example. Among them, the tannic acid-iron ion complex particles formed in the conversion system with 0.2 wt% are more than those with 0.1 wt%, and no significant agglomeration phenomenon appears in the samples with 0.4 and 0.8 wt%.
[0062] Figure 2 This is the physical photograph, the scanning electron microscope photographs in the horizontal and vertical directions of the silk fibroin-based iron tannate-coated composite aerogel in this example. The aerogel has an oriented pore structure in the vertical direction and a transverse honeycomb-like porous structure, providing channels for water transport and steam overflow; in the physical photograph, the composite aerogel is dark black, can absorb sunlight and convert it into heat energy, and the iron tannate coating inside and on the surface of its pores can resist the growth and reproduction of microorganisms on the surface of the aerogel.
[0063] Figure 3 This is the EDS mapping energy spectrum distribution diagram of the top cross-section of the silk fibroin-based iron tannate-coated composite aerogel in this example. It can be seen from the energy spectrum that the composite aerogel has the C, H, O, and N element signals of the silk fibroin material, the Si element signal in APTES, and the Fe element signal of ferric sulfate, and different element signals all have the porous profile of the aerogel, proving that the surface of the silk fibroin aerogel is uniformly modified with an iron tannate coating.
[0064] Figure 4 This is the X-ray photoelectron energy spectrum diagram of the silk fibroin-based iron tannate-coated composite aerogel. In the XPS spectrum, only the C, N, and O element signals appear in the silk fibroin aerogel, while in the silk fibroin-based iron tannate-coated composite aerogel, not only the C, N, and O element signals appear but also the Fe and Si element signals appear, proving the successful modification of the iron tannate coating.
[0065] Figure 5 This is the infrared spectrum of the silk fibroin-based iron tannate-coated composite aerogel. It can be seen from the spectrum that the silk fibroin-based iron tannate-coated composite aerogel shows absorption peaks at wavelengths of 1635 cm -1 , 1540 cm -1 , and 760 cm -1 , corresponding to the vibrations of -C=N, benzene ring stretching vibration, and TA-Fe 3+ respectively, which proves the successful modification of the iron tannate coating on the surface of the aerogel.
[0066] Figure 6 These are the OD values of Escherichia coli and Staphylococcus aureus after being cultured for 24 h under different pH conditions. Escherichia coli and Staphylococcus aureus with a concentration of 10 5 CFU / mL were cultured at a constant temperature of 37 °C for 24 h in solutions with pH values of 4, 4.5, 5, 5.5, 6, and 6.5 respectively. Then, the transmittance of the suspension at 600 nm was measured and converted into OD values. In the experimental group, when the pH was 5 or lower, the OD values of the bacteria decreased significantly, the solution was clear and transparent, and the bacteria hardly grew and reproduced, indicating that low pH would inhibit the bacterial activity and might mask the antibacterial effect of the nanozyme. When the pH reached 5.5 or higher, the suspensions of Escherichia coli and Staphylococcus aureus were relatively turbid, and the OD values could reach 0.30 and 0.46 or higher respectively, indicating that the inhibitory effect of pH on the growth and reproduction of bacteria was relatively small at this concentration. According to the TMB experiment, the color development reaction could be better promoted at pH 3-4, indicating that the catalytic reaction activity was higher at this time. However, due to the acid effect, the stability of the complex was poor at higher acidity. When the pH was 6-7, the stability of the complex was good, but at this time, the TMB experiment showed a poor color development effect, which was not conducive to the nanozyme catalysis. Therefore, pH 5.5 was selected as the optimal acidity condition. At this time, it would neither inhibit bacteria only due to acidity nor drive the nanozyme catalytic reaction and was beneficial to the stability of the complex.
[0067] Figure 7 These are the OD values of Escherichia coli and Staphylococcus aureus after being cultured for 24 h in an environment with different concentrations of hydrogen peroxide. Escherichia coli and Staphylococcus aureus with a concentration of 10 5Escherichia coli and Staphylococcus aureus at CFU / mL were incubated at a constant temperature of 37°C for 24 h with hydrogen peroxide solutions at 0 mM, 0.1 mM, 0.2 mM, 0.3 mM, 0.4 mM, and 0.5 mM under the condition that the pH of the liquid culture environment was 5. When the hydrogen peroxide content in the experimental group was 0.3 mM or higher, the OD value of the bacteria decreased significantly, the solution became clear and transparent, and the bacteria hardly grew and reproduced, indicating that when the hydrogen peroxide content was too high, it would directly kill bacteria and affect the antibacterial effect of nanozyme catalysis. When the hydrogen peroxide content was 0.2 mM, the OD values of Escherichia coli and Staphylococcus aureus were 0.15 and 0.31 respectively, which were close to the OD values of the control group without adding hydrogen peroxide, and the suspension was also relatively turbid, indicating that the inhibitory effect of hydrogen peroxide on the growth and reproduction of bacteria was small at this concentration. According to the results of the TMB experiment, a more significant color reaction could be induced when the hydrogen peroxide content was 0.2 mM, which could drive the nanozyme catalytic reaction better than 0.2 mM hydrogen peroxide. Therefore, in the subsequent antibacterial experiments, the substrate hydrogen peroxide concentration required for nanozyme-catalyzed antibacterial was set to 0.2 mM.
[0068] Figure 8 It is to study the nanozyme activity of silk fibroin-based iron tannate-coated composite aerogels with different iron contents. The iron content was regulated by preparing aerogels using different concentrations of ferric sulfate. Among them, the silk fibroin-based iron tannate-coated composite aerogels prepared using ferric sulfate concentrations of 0, 0.2, 0.4, and 0.8 wt% were named TA-Fe 3+ @SF-1, TA-Fe 3+ @SF-2, TA-Fe 3+ @SF-3, TA-Fe 3+ @SF-4. Whether using TMB or OPD and ABTS as substrates, the aerogel (TA-Fe 3+ @SF-4) prepared using a ferric sulfate concentration of 0.8 wt% had the most significant color development effect and the maximum light absorption value, indicating the strongest enzyme activity at this time. At the same time, TA-Fe 3+ @SF-3, and the aerogel prepared using a ferric sulfate concentration of 0.4 wt% also had strong nanozyme activity.
[0069] Figure 9 It is a graph of the photothermal heating data of silk fibroin-based iron tannate-coated composite aerogels with different iron contents under one sunlight intensity for 50 min. It can be seen from the photothermal heating data graph that the top layer temperatures of the silk fibroin-based iron tannate-coated composite aerogels corresponding to the conversion systems with iron concentrations of 0, 0.2, 0.4, and 0.8 wt% increased by 4.9°C, 6.0°C, 7.2°C, and 8.4°C respectively, proving that the silk fibroin-based iron tannate-coated composite aerogel has good photothermal heating effect, and the aerogel prepared using a ferric sulfate concentration of 0.8% has the best photothermal performance.
[0070] Figure 10 is the water evaporation rate and evaporation efficiency of silk fibroin-based iron tannate-coated composite aerogels with different iron contents. The iron content is controlled by adjusting the content of ferric sulfate (0, 0.2, 0.4, 0.8 wt%) during preparation. The water evaporation rates of the prepared silk fibroin-based iron tannate-coated composite aerogels are 1.94 kg m -2 h -1 、2.20 kg m -2 h -1 、2.71 kg m -2 h -1 and 2.52 kg m -2 h -1 , indicating that with the increase of the amount of ferric sulfate used, the water evaporation performance of the material also increases. Although the photothermal performance is better, the evaporation rate of the aerogel with 0.8 wt% ferric sulfate is lower than that of the silk fibroin-based iron tannate-coated composite aerogel with 0.4 wt%. Therefore, the silk fibroin-based iron tannate-coated composite aerogel prepared with 0.8 wt% ferric sulfate is selected for subsequent tests.
[0071] Antibacterial performance test of silk fibroin-based iron tannate-coated composite aerogel is as follows:
[0072] The inhibitory abilities of silk fibroin aerogel, silk fibroin aerogel added with H2O2 (0.2 mM), and silk fibroin-based iron tannate-coated composite aerogel against Escherichia coli and Staphylococcus aureus were qualitatively studied by the inhibition zone method. Different aerogel samples were placed on the culture plates coated with Escherichia coli and Staphylococcus aureus, cultured at 37 °C for 24 h, and then the diameter of the inhibition zone was observed and measured.
[0073] Figure 11 are the photos of the inhibition zones of the silk fibroin-based iron tannate-coated composite aerogel against Escherichia coli and Staphylococcus aureus. Whether there is H2O2 or not, no inhibition zone appears after the silk fibroin aerogel is cultured with Escherichia coli and Staphylococcus aureus, indicating that its antibacterial ability is limited, and H2O2 at this concentration cannot kill bacteria. However, obvious inhibition ranges appear around the silk fibroin-based iron tannate-coated composite aerogel samples on the bacterial and fungal culture plates, indicating that the means of nanozyme catalysis has good inhibitory ability against both bacteria and fungi.
[0074] Figure 12 The diameters of the inhibition zones on different culture plates were statistically analyzed. The diameters of the inhibition zones of the silk fibroin-based iron tannate-coated composite aerogel against Escherichia coli and Staphylococcus aureus are 23.7 ± 0.3 mm and 23.3 ± 0.6 mm respectively, indicating that the silk fibroin-based iron tannate-coated composite aerogel has excellent antibacterial ability.
[0075] Figure 13 The water evaporation performance and retention rate of the silk fibroin-based iron tannate-coated composite aerogel with or without H2O2 after 72 h of co-culture with the bacterial solution. The silk fibroin-based iron tannate-coated composite aerogel with nanozyme catalytic activity had evaporation rates of 2.47 kg m -2 h -1 and 2.52 kg m - 2 h -1 ， after 5 days of co-culture with Escherichia coli and Staphylococcus aureus, respectively. The retention rates of the evaporation rates reached 91.0% and 92.7%, respectively. The silk fibroin-based iron tannate-coated composite aerogel without nanozyme catalytic activity had evaporation rates that decreased to 1.90 kg m -2 h -1 and 2.13 kg m -2 h -1 after 5 days of co-culture with Escherichia coli and Staphylococcus aureus, respectively, and the retention rates compared to the original evaporation rates were 70.0% and 78.3%, respectively. Combining these results, the anti-biofouling design based on nanozyme catalysis enables the porous solar water evaporator to maintain stable evaporation performance in a water body rich in microorganisms.
[0076] Figure 14 shows the evaporation of the silk fibroin-based iron tannate-coated composite aerogel in high-concentration saline water. Under 1 sun intensity, the silk fibroin-based iron tannate-coated composite aerogel was placed in a 10 wt% sodium chloride solution, and after continuous evaporation for 10 h, no white salt crystals precipitated at the top of the aerogel, indicating its good salt tolerance. And the water evaporation rate was stable at about 2.55 kg m -2 h -1 during the 10 h, demonstrating the good salt tolerance of the silk fibroin-based iron tannate-coated composite aerogel.
[0077] Figure 15 shows that under 1 sun intensity, after the silk fibroin-based iron tannate-coated composite aerogel continuously underwent 20 evaporation cycles, its average water evaporation rate could be maintained at 2.58 kg m -2 h -1 , and the water evaporation performance was stable, indicating that the material has the potential for long-term cyclic use.
[0078] Figure 16 shows the determination of the metal ion concentrations in the initial artificial seawater and the condensed water collected after treatment with the silk fibroin-based iron tannate-coated composite aerogel by inductively coupled plasma atomic absorption spectrometry (ICP-AES). In the initial artificial seawater, Na + , Ca 2+ , Mg2+ , K + The ion concentrations were as high as 10417.9, 406.6, 1274, and 460.1 mg / L. After treatment, the Na + , Ca 2+ Mg 2+ , K + The ion concentrations were 10.55, 4.81, 0.92, and 11.89 mg / L, respectively. The ion concentrations were significantly reduced by 2 to 3 orders of magnitude, meeting the World Health Organization's requirements for drinking water.
[0079] Figure 17 The silk fibroin-based tannic acid iron-coated composite aerogel evaporates under actual outdoor sunlight for 10 hours, and the evaporation rate can reach up to 2.70 kg m -2 h -1 This indicates that the silk fibroin-based tannate iron coating composite aerogel has good practical evaporation performance.
[0080] The above description is merely a preferred embodiment of the present invention and is intended to be illustrative rather than restrictive of the present invention. Those skilled in the art will appreciate that many changes, modifications, and even equivalents may be made to the present invention within the spirit and scope of the claims, all of which fall within the scope of protection of the present invention.
Claims
1. A silk fibroin-based ferric tannate-coated composite aerogel, characterized in that, It includes a plant polyphenol coating and tannic acid-ferric ion formed complex nanoparticles, and the nanoparticles are uniformly distributed on the inner wall of the pore channels of the silk fibroin-based aerogel oriented pore channel structure.
2. A preparation method of the silk fibroin-based iron tannate-coated composite aerogel as described in claim 1, characterized in that, It includes the following steps: S1. Pour the silk fibroin solution into a polystyrene mold, freeze it by the freeze-casting method, place the mold on a copper plate pre-cooled by liquid nitrogen, control the addition amount of liquid nitrogen to keep the temperature constant at -20 °C, and then put it into a freeze dryer for freeze-drying for 48 h to obtain a silk fibroin aerogel with an oriented structure. S2. Immerse the silk fibroin-based aerogel obtained in step S1 in a methanol solution for fixation and washing, freeze it, and finally freeze-dry it to obtain a silk fibroin-based aerogel treated by hydrophobic treatment. S3. Immerse the silk fibroin-based aerogel obtained in step S2 in a mixed solution of tannic acid-Tris solution and APTES solution, fully immerse and adsorb tannic acid molecules, and alternately wash the excess tannic acid on the surface with deionized water and ethanol to obtain a silk fibroin-based tannic acid composite aerogel. S4. Immerse the silk fibroin-based tannic acid composite aerogel obtained in step S3 in a ferric sulfate solution to form tannic acid-ferric ion complexes on the surface of the aerogel, then wash the excess solution on the surface of the aerogel with deionized water, and then freeze-dry the aerogel to obtain a silk fibroin-based tannic acid iron coating composite aerogel.
3. The preparation method of a silk fibroin-based tannic acid iron-coated composite aerogel according to claim 2, characterized in that, In step S1, the freeze-casting method is carried out using liquid nitrogen.
4. The preparation method of a silk fibroin-based iron tannate-coated composite aerogel according to claim 2, characterized in that, In step S3, the volume ratio of the tannic acid-Tris solution to the APTES solution is 5:
1.
5. The preparation method of a silk fibroin-based iron tannate-coated composite aerogel according to claim 2, characterized in that, In step S3, the concentration of tannic acid in the tannic acid-Tris solution is 0.2 wt%, and the concentration of APTES solution is 1 wt%.
6. The preparation method of a silk fibroin-based iron tannate-coated composite aerogel according to claim 2, characterized in that, In step S4, the iron content in the ferric sulfate solution is 0.2 - 0.8 wt%.
7. Application of the silk fibroin-based tannic acid iron coating composite aerogel as described in claim 1 in interfacial solar-driven photothermal water treatment.