A carbon-based silver sulfide composite aerogel with synergistic enhanced light harvesting and anti-biofouling properties, its preparation method, and its application.

Abstract

This invention relates to the field of nanocomposite materials technology, specifically to a carbon-based silver sulfide composite aerogel with synergistically enhanced light-harvesting and biofouling resistance, its preparation method, and its applications. The method involves pouring a chitosan-graphene solution into a polystyrene mold and using different cryogenic casting methods to obtain chitosan-graphene aerogels with different orientations. Carbonization under a N2 atmosphere yields carbon-based aerogels with different structures. Immersion in a tannic acid-Tris solution allows for the adsorption of tannic acid molecules. After washing with deionized water, the aerogels are immersed in a silver nitrate solution to form tannic acid-silver ion complexes. Further washing with deionized water and immersion in a thioacetamide solution yields carbon-based silver sulfide composite aerogels with different structures. This method solves the problem of performance loss due to biofouling in carbon-based three-dimensional porous materials. The carbon-based silver sulfide aerogel exhibits superior light absorption and photothermal properties compared to carbon-based zinc oxide aerogels, overcoming the problem of weakened evaporation performance in conventional anti-biofouling designs.

Description

Technical Field

[0001] This invention relates to the field of nanocomposite materials technology, specifically to a carbon-based silver sulfide composite aerogel with synergistic enhancement of light capture and resistance to biofouling, its preparation method, and its applications. Background Technology

[0002] Solar-driven interfacial evaporation, as a clean and efficient seawater desalination technology, has broad application prospects in alleviating freshwater shortages. In this process, heat concentrates near the surface of the evaporator, accelerating water vapor generation and achieving rapid water evaporation. Carbon materials are widely available and inexpensive, possessing high efficiency in photothermal conversion and accelerated water evaporation, making them a research hotspot in solar-driven interfacial water evaporation materials. Although carbon materials generally cannot provide sufficient nutrients, their good adsorption properties may promote the attachment and accumulation of microorganisms in natural water bodies such as seawater, lakes, and rivers, leading to biofouling, clogging the water transport channels inside the evaporator, reducing the evaporator's light absorption performance, and significantly decreasing the evaporation rate, severely impacting the application of the materials. In recent years, composite evaporation materials with anti-biofouling properties have been applied to solar interfacial water evaporation. However, conventional anti-biofouling designs focus on antimicrobial properties, neglecting the influence of antimicrobial components and design on the light absorption and photothermal properties of the evaporation material, often weakening the material's intrinsic evaporation performance. Therefore, it is necessary to develop novel anti-biofouling solar evaporation materials that balance light absorption and microbial inhibition.

[0003] In view of the above-mentioned defects, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of biofouling caused by the growth and reproduction of microorganisms inside carbon-based three-dimensional porous materials, which leads to pore blockage, loss of photothermal performance and thus affects the normal use of the material. The invention provides a carbon-based silver sulfide composite aerogel with synergistic enhancement of light capture and anti-biofouling, its preparation method and application.

[0005] To achieve the above objectives, this invention discloses a method for preparing a carbon-based silver sulfide composite aerogel with synergistically enhanced light-harvesting and biofouling resistance, comprising the following steps:

[0006] S1, Preparation of chitosan graphene aerogel: Chitosan graphene solution is poured into a polystyrene mold, frozen using different freeze casting methods, and then freeze-dried to obtain chitosan graphene aerogels with different orientation structures. Carbonization under N2 atmosphere yields carbon-based aerogels with different structures.

[0007] S2, Preparation of carbon-based silver sulfide composite aerogels: Carbon-based aerogels with different structures are immersed in tannic acid-Tris solution to fully absorb and adsorb tannic acid molecules. After washing off excess tannic acid on the surface with deionized water, they are immersed in silver nitrate solution to form tannic acid-silver ion complexes. After washing with deionized water, they are immersed in thioacetamide solution to obtain carbon-based silver sulfide composite aerogels with different structures.

[0008] In step S1, the mass ratio of chitosan to graphene is 15:5.

[0009] In step S1, the chitosan graphene aerogels with different orientation structures include vertical structures, layered structures, and disordered structures.

[0010] The vertically structured chitosan-graphene aerogel was prepared using an orientation freezing method. The specific process is as follows: the chitosan-graphene mixture was poured into a polystyrene mold on a cold plate, and liquid nitrogen was poured in to control the temperature.

[0011] The layered chitosan graphene aerogel was prepared by an oriented freezing method, the specific process of which is as follows: a mold with wedge-shaped PDMS at the bottom was used for freezing preparation. The mixture was poured into a cylindrical mold on a cold plate, and liquid nitrogen was poured in to control the temperature.

[0012] The disordered chitosan graphene aerogel was prepared by placing a mold containing a mixture in a refrigerator.

[0013] In step S1, the carbonization process is as follows: heating from 20°C to 500°C at a heating rate of 2°C / min and holding for 1 hour; heating from 500°C to 800°C at a heating rate of 5°C / min and holding for 2 hours.

[0014] In step S2, the Tris buffer concentration is 0.1 mM, the reaction is carried out in 5 mg / mL silver nitrate solution for 30 min, and the sulfidation time is 6-8 h.

[0015] This invention also discloses a carbon-based silver sulfide composite aerogel with synergistic enhancement of light harvesting and anti-biofouling properties prepared by the above-described method. The aerogel comprises a carbon-based aerogel oriented pore structure, a plant polyphenol coating, and silver sulfide nanoparticles. The silver sulfide nanoparticles are uniformly distributed within the inner walls of the pores of the carbon-based aerogel oriented pore structure. The carbon-based silver sulfide composite aerogel exhibits a light harvesting capacity of 1 kW / m³. 2 Under simulated solar radiation intensity, the evaporation rate is approximately 1.87 kg / m³. -2 h -1 .

[0016] This invention also discloses the application of the above-mentioned synergistically enhanced light-harvesting and biofouling-resistant carbon-based silver sulfide composite aerogel in interfacial solar-driven photothermal treatment.

[0017] The carbon-based silver sulfide composite aerogel prepared in this invention comprises a porous structure with different orientations and a silver sulfide antifouling coating. This aerogel exhibits a stable structure and excellent water evaporation performance. The oriented porous structure of the aerogel facilitates water transport while ensuring continuous and efficient water evaporation. In-situ growth of silver sulfide nanoparticles within the carbon-based porous aerogel provides excellent antifouling properties and enhances the light absorption and photothermal properties of the carbon material. Compared to carbon-based aerogels, the carbon-based silver sulfide aerogel exhibits better water evaporation performance. Furthermore, this carbon-based silver sulfide composite aerogel is highly effective in inhibiting biofouling, keeping the aerogel pores unobstructed and protecting it from fouling by microorganisms such as Escherichia coli and Staphylococcus aureus, thus maintaining a long-term stable water evaporation rate. In addition, the evaporation rate is recyclable in treating simulated wastewater and simulated seawater containing phycoerythramine or methylene blue dyes.

[0018] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention designs and prepares biomimetic oriented porous carbon-based silver sulfide aerogels with various structures, which can improve the light energy capture and utilization and evaporation performance of carbon-based aerogels, and solve the problem of performance loss due to biofouling of existing carbon-based evaporation materials. In contrast, although conventional carbon-based aerogels have good evaporation performance, they are easily fouled by bacteria and other microorganisms, leading to a decrease in light absorption and photothermal performance, resulting in evaporation performance loss. Furthermore, while conventional carbon-based zinc oxide aerogels have similar antibacterial properties, their light absorption, photothermal, and water evaporation performance are significantly lower than those of carbon-based aerogels, indicating that the design of anti-biofouling materials for carbon-based evaporation materials needs to take into account light energy capture and utilization to achieve synergy between anti-biofouling and evaporation. Attached Figure Description

[0019] Figure 1 Scanning images and optical images of carbon-based silver sulfide composite aerogels with different structures are shown. a represents the vertical structure, b represents the layered structure, and c represents the disordered structure.

[0020] Figure 2 Elemental distribution diagrams of cross-sections of carbon-based silver sulfide composite aerogels with different structures; Figure 3 XRD patterns of carbon-based silver sulfide composite aerogels with different structures;

[0021] Figure 4 XPS spectra of carbon-based silver sulfide composite aerogels with different structures;

[0022] Figure 5 Optical absorption spectra of carbon-based silver sulfide composite aerogels with different structures;

[0023] Figure 6 Photothermal temperature rise data of carbon-based silver sulfide composite aerogels with different structures under irradiation with one solar intensity;

[0024] Figure 7 The water evaporation rate and evaporation efficiency of carbon-based silver sulfide composite aerogels with different structures;

[0025] Figure 8 Photographs of the inhibition zones of carbon-based silver sulfide composite aerogels (a) and carbon-based aerogels (b) in Escherichia coli and Staphylococcus aureus;

[0026] Figure 9 The diameter of the inhibition zone of carbon-based silver sulfide composite aerogels with different structures in Escherichia coli and Staphylococcus aureus is shown.

[0027] Figure 10 Scanning electron microscope images of carbon-based silver sulfide composite aerogels with different structures and carbon-based aerogels after culturing Escherichia coli and Staphylococcus aureus for 72 h.

[0028] Figure 11 Figures showing the water evaporation and retention capacity of carbon-based silver sulfide composite aerogels (a) and carbon-based aerogels (b) before and after bacterial culture under irradiation at one solar intensity.

[0029] Figure 12 The light absorption spectra of carbon-based silver sulfide composite aerogels and carbon-based aerogels before and after co-culturing with Escherichia coli and Staphylococcus aureus are shown.

[0030] Figure 13 Photothermal temperature rise data of carbon-based silver sulfide composite aerogels with different structures and carbon-based aerogels before and after co-culturing with Escherichia coli and Staphylococcus aureus;

[0031] Figure 14 Figure 1 shows the water evaporation capacity of carbon-based silver sulfide composite aerogels with different structures after 15 cycles of artificial seawater circulation.

[0032] Figure 15 A physical image showing the salt-out resistance of a vertically structured carbon-based silver sulfide composite aerogel.

[0033] Figure 16 Changes in sodium, magnesium, potassium, and calcium ion concentrations in water before and after treatment with vertically structured carbon-based silver sulfide composite aerogel;

[0034] Figure 17 UV-Vis spectra of solutions before and after treatment with phycoerythrone and methylene blue dyes using carbon-based silver sulfide composite aerogel with a vertical structure;

[0035] Figure 18 Scanning images and optical images of the vertically structured carbon-based zinc oxide composite aerogel in the comparative example;

[0036] Figure 19The XRD pattern of the vertically structured carbon-based zinc oxide composite aerogel in the comparative example;

[0037] Figure 20 The light absorption spectra of the vertically structured carbon-based zinc oxide composite aerogel and carbon-based aerogel are shown in the comparative example.

[0038] Figure 21 The graph shows the photothermal temperature rise data of the vertically structured carbon-based zinc oxide composite aerogel and carbon-based aerogel under irradiation with one solar intensity in the comparative example.

[0039] Figure 22 Photographs of the inhibition zones of vertically structured carbon-based zinc oxide composite aerogel (a) and carbon-based aerogel (b) in Escherichia coli and Staphylococcus aureus, respectively;

[0040] Figure 23 The diameter of the inhibition zone in Escherichia coli and Staphylococcus aureus is shown for the vertically structured carbon-based zinc oxide composite aerogel and carbon-based aerogel in the comparative examples. Detailed Implementation

[0041] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] This embodiment prepares carbon-based aerogels with different structures, and the specific steps are as follows:

[0044] (1) Take 4g of chitosan powder and mix it evenly into 98mL of deionized water and 2mL of acetic acid. Stir overnight to obtain a 4% chitosan solution.

[0045] (2) Take 0.4g of graphene oxide powder and mix it evenly into 40mL of deionized water. Disperse it in an ultrasonic crusher at 500W for 5min to obtain a graphene oxide solution with a concentration of 10mg / mL.

[0046] (3) Mix the prepared chitosan and graphene oxide solution at a mass ratio of 15:5, and ultrasonically crush them at 700W for 10 minutes to obtain a chitosan-graphene oxide mixed solution.

[0047] (4) The chitosan-graphene oxide mixed solution was subjected to orientation freezing using different methods; the vertically oriented aerogel was prepared by orientation freezing, in which the mixture was poured into a cylindrical mold on a cold plate and liquid nitrogen was poured in to control the temperature; the layered aerogel was prepared by freezing with a mold having wedge-shaped PDMS at the bottom, in which the mixture was poured into a cylindrical mold on a cold plate and liquid nitrogen was poured in to control the temperature; the disordered aerogel was prepared by placing a mold containing the mixture in a refrigerator. Then, the initial chitosan-graphene oxide aerogel was obtained by freeze-drying for 60 hours.

[0048] (5) Chitosan-graphene oxide aerogels with different structures were calcined in a nitrogen atmosphere. The carbonization process was as follows: heating from 20℃ to 500℃ at a heating rate of 2℃ / min and holding for 1h; heating from 500℃ to 800℃ at a heating rate of 5℃ / min and holding for 2h. Carbon-based aerogels with different structures were obtained.

[0049] Example 2

[0050] This embodiment prepares carbon-based silver sulfide composite aerogels with different structures and carbon-based zinc oxide aerogels with vertical structures. The specific steps are as follows:

[0051] (1) Preparation of tannic acid-Tris buffer solution: Dissolve 0.2g of tannic acid powder in 100mL of Tris-HCl buffer solution (pH=8.5) and sonicate for 10min to obtain tannic acid-Tris buffer solution;

[0052] (2) Carbon-based aerogels with different structures were immersed in the above solution to fully adsorb tannic acid. After washing, they were placed in a 5 mg / mL silver nitrate solution for chelation and coordination for 30 min. After washing, 0.1 mM thioacetamide solution was used to convert the silver tannic acid complex into silver sulfide to obtain carbon-based silver sulfide composite aerogels with different structures.

[0053] Comparative Example

[0054] The vertically structured carbon-based aerogel, which fully adsorbed tannic acid, was washed and placed in a 0.1 M zinc acetate solution for chelation and coordination for 30 min. After washing, the tannic acid silver complex was converted into zinc carbonate using a 0.05 M sodium carbonate solution. After high-temperature calcination, a vertically structured carbon-based zinc oxide composite aerogel was obtained.

[0055] Figure 1 The images show actual photographs, horizontal and vertical scanning electron microscope images of carbon-based silver sulfide composite aerogels with different structures in this embodiment. The vertically structured aerogel has an oriented pore structure in the vertical direction and a honeycomb porous structure in the horizontal direction, providing channels for water transport and steam overflow. In the actual photographs, the composite aerogel is dark black and can absorb sunlight and convert it into heat energy. The silver sulfide nanoparticles inside the pores and on the surface can resist the growth and reproduction of microorganisms on the surface of the aerogel.

[0056] Figure 2 The image shows the EDS mapping distribution of the top cross-section of the carbon-based silver sulfide composite aerogels with different structures in this embodiment. The energy spectra show that the composite aerogels contain C and O elemental signals from carbon materials and S and Ag elemental signals from silver sulfide. The signal distribution exhibits a porous profile of the aerogel, demonstrating that the top of the carbon-based aerogel is uniformly modified with a silver sulfide layer.

[0057] Figure 3These are XRD patterns of carbon-based silver sulfide composite aerogels with different structures. The XRD patterns show that these carbon-based silver sulfide composite aerogels contain silver sulfide nanoparticles.

[0058] Figure 4 These are X-ray photoelectron spectra of carbon-based silver sulfide composite aerogels with different structures. The XPS spectra show signals for C and O elements, as well as Ag and S elements, confirming the presence of the Ag₂S layer.

[0059] Figure 5 These are the light absorption spectra of carbon-based silver sulfide composite aerogels with different structures. The light absorption spectra show that the UV absorption rates of the vertical, layered, and disordered carbon-based aerogels are 97.4%, 97.6%, and 94.4%, respectively; while the UV absorption rates of the vertical, layered, and disordered carbon-based silver sulfide aerogels are 98.0%, 98.1%, and 96.1%, respectively, demonstrating high UV absorption performance.

[0060] Figure 6 The graph shows the photothermal temperature rise data of carbon-based silver sulfide composite aerogels with different structures under 40 minutes of sunlight irradiation. The graphs show that the temperature changes of vertical, layered, and disordered carbon-based aerogels are 10℃, 9.6℃, and 9.7℃, respectively; while the temperature changes of vertical, layered, and disordered carbon-based silver sulfide aerogels are 10.8℃, 10.5℃, and 10.5℃, respectively. The carbon-based silver sulfide composite aerogels exhibit good photothermal temperature rise performance.

[0061] Figure 7 The evaporation rates and evaporation efficiencies of carbon-based silver sulfide composite aerogels with different structures are shown. The evaporation rates of vertical, layered, and disordered carbon-based silver sulfide aerogels are 1.87 kg m³ and 1.87 kg m³, respectively. -2 h -1 1.68kg m -2 h -1 1.47kg m -2 h -1 The evaporation efficiencies were 85.3%, 77.8%, and 64.1%, respectively.

[0062] The antibacterial properties of carbon-based silver sulfide composite aerogels with different structures were tested using the following steps:

[0063] The inhibitory effects of carbon-based aerogels and carbon-based silver sulfide aerogels with different structures on Escherichia coli and Staphylococcus aureus were qualitatively studied using the inhibition zone method. Different aerogel samples were placed on culture plates coated with Escherichia coli and Staphylococcus aureus, and incubated at 37°C for 24 h. The diameter of the inhibition zone was then observed and measured.

[0064] Figure 8These are images of inhibition zones of carbon-based aerogels and carbon-based silver sulfide aerogels with different structures against *Escherichia coli* and *Staphylococcus aureus*. None of the three carbon-based aerogel structures showed inhibition zones in high concentrations of *E. coli* and *Staphylococcus aureus*, indicating that pure carbon-based aerogels do not have antibacterial effects. However, the three carbon-based silver sulfide aerogel structures showed clear inhibition zones, demonstrating that different structures of carbon-based silver sulfide aerogels have good inhibitory ability on the growth of *E. coli* and *Staphylococcus aureus*.

[0065] Figure 9 The inhibition zone diameters of carbon-based aerogels and carbon-based silver sulfide aerogels with different structures were statistically analyzed. The inhibition zone diameters of vertical, layered, and disordered carbon-based silver sulfide aerogels against Escherichia coli were 18.7 mm, 19.8 mm, and 18.5 mm, respectively; and the inhibition zone diameters against Staphylococcus aureus were 18.3 mm, 20.8 mm, and 18.1 mm, respectively. The inhibition zone diameter of carbon-based aerogels was negligible, demonstrating that carbon-based silver sulfide aerogels possess certain antibacterial capabilities.

[0066] Figure 10 This figure shows the water evaporation and retention capacity of carbon-based aerogels and carbon-based silver sulfide aerogels with different structures after co-culturing with bacteria for 72 hours. In pure water, the water evaporation rates of vertical, layered, and disordered carbon-based aerogels are 1.78 kg m³ / s, respectively. -2 h -1 1.61kg m -2 h -1 1.36kg m -2 h -1 The water evaporation rates of vertical, layered, and randomly oriented carbon-based silver sulfide aerogels were 1.87 kg m³, respectively. -2 h -1 1.68kg m -2 h -1 1.47kg m -2 h -1 After co-culturing carbon-based aerogels with different structures with *E. coli*, the water evaporation rate was measured again. The results showed that the water evaporation rate of the carbon-based aerogels was significantly reduced to 1.28 kg / m³. -2 h -1 1.13kg m -2 h -1 1.04kg m -2 h -1 The three types of carbon-based silver sulfide aerogels could only maintain 71.9%, 70.2%, and 76.5% of the original water evaporation rate, while the water evaporation rates of the three orientations remained at 1.73 kg m³. -2 h -1 1.51kg m -2 h -1With 1.31kg m -2 h -1 The water evaporation rates remained at 92.5%, 89.9%, and 89.1% of the original water evaporation rates, respectively, significantly higher than those of carbon-based aerogels with the same structure. After co-culturing with Staphylococcus aureus, the water evaporation rates of the vertical, layered, and disordered orientations of the carbon-based aerogels significantly decreased to 1.24 kg m³. -2 h -1 1.08kg m -2 h -1 1.04kg m -2 h -1 The three types of carbon-based silver sulfide aerogels could only maintain 69.7%, 67.1%, and 76.5% of the original water evaporation rate, while the water evaporation rates of the three orientations remained at 1.73 kg m³. -2 h -1 1.51kg m -2 h -1 With 1.30kg m -2 h -1 The evaporation rates remained at 92.5%, 89.9%, and 88.4% of the original water evaporation rate, significantly higher than those of carbon-based aerogels with the same structure. These results combined demonstrate that the anti-biofouling design allows porous solar water evaporators to maintain stable evaporation performance in microbially rich water bodies.

[0067] Carbon-based aerogels with different structures were compared with carbon-based silver sulfide aerogels at 10 5 CFU / mL Escherichia coli solution and Staphylococcus aureus solution were co-cultured and placed in a shaker at 37°C for 72 h. After a series of processes including rinsing, fixation, gradient ethanol washing and freeze-drying, the samples were observed using a scanning electron microscope.

[0068] Figure 11 These are scanning electron microscope (SEM) images of three types of carbon-based aerogels and carbon-based silver sulfide aerogels after culturing with *E. coli* and *Staphylococcus aureus* for 72 hours. The carbon-based aerogels with different structures exhibited a large number of corresponding bacterial species adhering to their surfaces and within their pores, accumulating and forming dense biofilms that blocked the pores. In contrast, the carbon-based silver sulfide aerogels with different structures, after co-culturing with their respective bacterial solutions, showed only a small number of bacterial cells adhering to their surfaces and within their pores, maintaining their structural integrity. This indicates that carbon-based aerogels are susceptible to biofouling. The silver sulfide-modified carbon-based aerogels effectively inhibit bacterial growth and reproduction, ensuring the aerogel material is protected from microbial contamination that could lead to pore blockage and maintaining unobstructed water transport channels.

[0069] Figure 12 , 13The figures show the UV-Vis-NIR absorption spectra and photothermal heating curves of carbon-based aerogels and carbon-based silver sulfide aerogels with different structures after co-culturing with *Escherichia coli* and *Staphylococcus aureus* for 72 hours. As can be seen from the figures, after biofouling, the light absorption rate of carbon-based aerogels with different structures decreased overall, with absorption rates below 90% in most wavelength ranges. In contrast, carbon-based silver sulfide aerogels maintained a similar light absorption rate to before biofouling, with absorption rates exceeding 90% in the 280-2500 nm spectral range. This decrease in light absorption also led to a deterioration in the photothermal heating effect of the aerogels. After co-culturing with *E. coli*, under strong sunlight irradiation, the temperature changes of vertical, layered, and disordered carbon-based aerogels within 40 minutes decreased from the original 35.3℃, 35.9℃, and 35.5℃ to 29.2℃, 27.9℃, and 27.7℃, respectively. The photothermal heating effect was significantly reduced. The temperature changes of vertical, layered, and disordered carbon-based silver sulfide aerogels within 40 minutes decreased only from the original 37.7℃, 36.9℃, and 35.4℃ to 37.3℃, 36.9℃, and 36℃, respectively. The photothermal heating effect did not decrease significantly. This explains the mechanism by which biofouling reduces the water evaporation rate of porous materials. On the one hand, the biofilm on the surface of porous materials reduces the material's light absorption rate, affecting light absorption; on the other hand, the reduced light absorption rate also worsens the material's photothermal conversion performance, thus reducing the water evaporation rate.

[0070] Figure 14 The carbon-based silver sulfide composite aerogel was circulated and evaporated 15 times in artificial seawater under one solar radiation intensity, maintaining a rate of 1.88 kg / m³. -2 h -1 It exhibits stable water evaporation performance.

[0071] Figure 15 This is a photograph demonstrating the salt-out resistance of carbon-based silver sulfide composite aerogel. When 0.2g of NaCl crystals were placed on the surface of the vertically structured carbon-based silver sulfide aerogel, the NaCl crystals gradually disappeared within 30 minutes, indicating that the salt dissolved in the water. This is due to the combined effect of the aerogel's excellent hydrophilicity and the vertically arranged microchannels, which provide sufficient water to the surface, allowing the NaCl crystals to dissolve in the water through capillary action and be transferred back into the overall water.

[0072] The concentration of metal ions in the condensate collected after treatment with initial artificial seawater and carbon-based silver sulfide composite aerogel was determined by inductively coupled plasma atomic absorption spectrometry (ICP-AES). Figure 16 As shown, the initial artificial seawater Na + Mg 2+ K + Ca 2 +The ion concentrations were as high as 9600, 1070, 598.4, and 407.18 mg / L. Na+ was collected from the condensate after treatment. + Mg 2+ K + Ca 2+ The ion concentrations were 2.76, 0.55, 12.65, and 1.98 mg / L, respectively, which significantly decreased by 3-4 orders of magnitude.

[0073] Figure 17 The image shows a comparison between the collected condensate and the original solutions in the treatment of dye wastewater (phycoerythrone and methylene blue) using a vertically structured carbon-based silver sulfide aerogel. Optical images reveal that the original solutions are red and blue, while the collected condensate is a clear, transparent, colorless liquid. UV-Vis absorption spectroscopy analysis of both the dye solutions and the collected condensate shows that the characteristic absorption peaks of both dyes are absent from the UV-Vis absorption spectrum of the collected condensate. This demonstrates that the aerogel still possesses good purification properties for wastewater containing organic dyes.

[0074] Figure 18 The images show a comparative photograph of a vertically structured carbon-based zinc oxide aerogel and a transverse scanning electron microscope image. The vertically structured aerogel has an oriented pore structure in the vertical direction and a transverse honeycomb porous structure, providing channels for water transport and vapor escape. Zinc oxide is a good broad-spectrum bactericide that can effectively inhibit the accumulation of bacteria inside the pores, but it appears dark white on the surface of the composite aerogel, which weakens the material's absorption of light and reduces the material's photothermal effect.

[0075] Figure 19 The XRD patterns of the vertically structured carbon-based zinc oxide aerogels are shown in the figures. The XRD patterns show that the carbon-based zinc oxide composite aerogels contain zinc oxide nanoparticles.

[0076] Figure 20 The images show the light absorption spectra of carbon-based zinc oxide aerogel and carbon-based silver sulfide composite aerogel with a vertical structure. The light absorption spectra show that the ultraviolet absorption rate of the carbon-based aerogel is 97.40%, while that of the carbon-based zinc oxide aerogel is 89.7%. This is because the modification of zinc oxide increases light reflection, which reduces the light absorption of the material.

[0077] Figure 21 This is a comparative graph showing the photothermal temperature rise of vertically structured carbon-based zinc oxide aerogel and carbon-based aerogel under sunlight intensity for 40 minutes. The graph shows that the carbon-based aerogel changes temperature by 10℃, while the carbon-based zinc oxide aerogel changes temperature by 7.9℃. This is because the zinc oxide modification increases light reflection and reduces light absorption, leading to a decrease in photothermal temperature rise performance.

[0078] Figure 22 These are comparative photographs of the inhibition zones of vertically structured carbon-based zinc oxide aerogels against *Escherichia coli* and *Staphylococcus aureus*. The carbon-based zinc oxide aerogels exhibit a clear inhibition zone, indicating that the vertically structured carbon-based zinc oxide aerogels have a good inhibitory effect on the growth of *Escherichia coli* and *Staphylococcus aureus*.

[0079] Figure 23 The figures show the inhibition zone diameters of carbon-based zinc oxide aerogels with vertical structures in a comparative manner. The inhibition zone diameters of the aerogels against Escherichia coli and Staphylococcus aureus are 22.2 mm and 21.5 mm, respectively, demonstrating that carbon-based zinc oxide aerogels have certain antibacterial capabilities.

[0080] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A method for the preparation of carbon-based silver sulfide composite aerogels with synergistically enhanced light harvesting and anti-biofouling, characterized in that, The method comprises the following steps: S1, preparing chitosan graphene aerogel: pouring chitosan graphene solution into a polystyrene mold, freezing by different freeze casting methods, and then freeze-drying to obtain chitosan graphene aerogel with different orientation structures, and carbonizing under N2 atmosphere to obtain carbon-based aerogel with different structures; S2, preparing carbon-based silver sulfide composite aerogel: soaking the carbon-based aerogel with different structures in a tannic acid-Tris solution, fully soaking and adsorbing tannic acid molecules, washing the surface excess tannic acid with deionized water, and then soaking in a silver nitrate solution to form a tannic acid-silver ion complex, and then washing with deionized water and soaking in a thioacetamide solution to obtain carbon-based silver sulfide composite aerogel with different structures.

2. A process for the preparation of carbon based silver sulfide composite aerogels with synergistically enhanced light harvesting and anti-biofouling as claimed in claim 1, wherein, In the step S1, the mass ratio of chitosan to graphene is 15:

5.

3. A process for the preparation of carbon based silver sulfide composite aerogels with synergistically enhanced light harvesting and anti-biofouling as claimed in claim 1, wherein, The chitosan graphene aerogel with different orientation structures in the step S1 includes vertical structure, layered structure and disordered structure.

4. A process for the preparation of a biorepellent carbon-based silver sulfide composite aerogel with synergistically enhanced light-trapping and biorepellence as claimed in claim 3, wherein, The chitosan graphene aerogel with vertical structure is prepared by orientation freezing method, and the specific process is as follows: pouring the chitosan graphene mixture into a polystyrene mold on a cold plate, and pouring liquid nitrogen to control the temperature.

5. A process for the preparation of carbon based silver sulfide composite aerogels with synergistically enhanced light harvesting and anti-biofouling as claimed in claim 3, wherein, The chitosan graphene aerogel with layered structure is prepared by orientation freezing method, and the specific process is as follows: using a mold with a wedge-shaped PDMS at the bottom to freeze, pouring the mixture into a cylindrical mold on a cold plate, and pouring liquid nitrogen to control the temperature.

6. A process for the preparation of carbon based silver sulfide composite aerogels with synergistically enhanced light harvesting and anti-biofouling as claimed in claim 3, wherein, The chitosan graphene aerogel with disordered structure is prepared by placing the mold containing the mixture in a refrigerator.

7. A process for the preparation of carbon based silver sulfide composite aerogels with synergistically enhanced light harvesting and anti-biofouling as claimed in claim 1, wherein, In the step S1, the carbonization program is as follows: heating from 20℃ to 500℃ at a rate of 2℃ / min, holding for 1h, heating from 500℃ to 800℃ at a rate of 5℃ / min, and holding for 2h.

8. A process for the preparation of carbon based silver sulfide composite aerogels with synergistically enhanced light harvesting and anti-biofouling as claimed in claim 1, wherein, In the step S2, the concentration of Tris buffer is 0.1mM, the reaction time in 5mg / mL silver nitrate solution is 30min, and the sulfuration time is 6-8h.

9. A carbon-based silver sulfide composite aerogel with synergistically enhanced light harvesting and anti-biofouling properties, prepared by the method of any one of claims 1 to 8, wherein, The carbon-based aerogel oriented pore structure, a plant polyphenol coating, silver sulfide nanoparticles uniformly distributed in the pore inner wall of the carbon-based aerogel oriented pore structure, the carbon-based silver sulfide composite aerogel has an evaporation amount of 1.87 2 under the simulated sunlight intensity of 1 kW / m .

10. The application of the carbon-based silver sulfide composite aerogel with synergistic enhanced light capture and anti-biofouling according to claim 9 in interface solar-driven photothermal water treatment.

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