Moss carbonized film gel composite double-layer evaporator and preparation method thereof
By preparing a double-layer evaporator composed of moss carbonization film and hydrogel, the problems of heat loss and structural stability of biomass photoevaporators were solved, achieving efficient and stable photothermal conversion and water transport, and adapting to the evaporation needs of environments with different salt concentrations.
Patent Information
- Application Number
- CN202610249023.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-03
- Publication Date
- 2026-05-15
AI Technical Summary
Existing biomass photovoltaic evaporators suffer from problems such as large heat loss, insufficient structural stability, and low solar energy utilization, making it impossible to achieve efficient evaporation.
Moss material is freeze-dried and then carbonized to form a carbonized moss membrane, which is then combined with a hydrogel made of polyvinyl alcohol and phytic acid. A moss carbonized membrane-gel composite double-layer evaporator is prepared by hydrophobic modification treatment. The mechanical strength is enhanced by utilizing the photothermal conversion capability of the carbon membrane and the water transport and thermal management capability of the hydrogel.
It improves the photothermal conversion efficiency of the photoevaporator, reduces heat loss, enhances water transport capacity and mechanical stability, adapts to environments with different salt concentrations, keeps the photothermal conversion interface dry and clean, and achieves efficient evaporation.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of photo-evaporation water desalination technology, specifically relating to a moss carbonization membrane gel composite double-layer evaporator and its preparation method. Background Technology
[0002] In recent years, under the economic and ecological framework of the dual-carbon concept (carbon peaking and carbon neutrality), solar-driven interfacial evaporation technology has been proposed to alleviate water scarcity and has become a promising technology for increasing freshwater supply with minimal carbon footprint. However, natural light energy is dispersed in natural evaporation, resulting in limited solar energy utilization. Furthermore, water has low heat absorption efficiency, rapid heat dissipation, and significant heat loss, making efficient evaporation impossible. Therefore, it is necessary to design high-efficiency solar evaporators to optimize the conversion efficiency of light energy to heat energy and the ability to localize heat, thereby achieving efficient photoevaporation.
[0003] With the rise of solar interfacial evaporators, many excellent photoevaporation materials have been studied. Among them, biomass materials have shown great development potential in the material screening of solar evaporators due to their advantages such as excellent natural structure, abundant resources and low cost. For example, Jiang et al. used bamboo leaf charcoal (BLC) and heat-insulating macroporous melamine foam (MF) to prepare a three-dimensional photoevaporator (DOI: 10.1016 / j.cej.2023.148289); Li et al. reported a method for preparing a photoevaporator based on lignin carbon quantum dots (LCQD) modified chitosan carbon aerogel (C-LCDCA) (DOI: 10.1016 / j.cej.2024.150157); Wen et al. used loofah sponge as a skeleton to construct an MXene / cellulose nanofiber (CNF) aerogel photoevaporator for photoevaporation (DOI: 10.1016 / j.jcis.2023.04.081). However, biomass-derived photothermal evaporators also have drawbacks such as large heat loss and insufficient structural stability. Therefore, their performance often needs to be optimized by combining artificial nanotechnology in their design and use. Summary of the Invention
[0004] This invention primarily provides a photoevaporator with strong water transport capacity, good thermal management capabilities, and high mechanical strength, overcoming the thermal loss disadvantage inherent in the natural structure of biomass and the insufficient photothermal conversion of the gel layer nanostructure in existing technologies. The technical solution is as follows:
[0005] A method for preparing a moss carbonized film-gel composite double-layer evaporator includes the following steps: freeze-drying moss material and then carbonizing it under a protective atmosphere to obtain a carbonized moss film; mixing and dissolving polyvinyl alcohol and phytic acid, and adding glutaraldehyde to form a hydrogel; then placing the carbonized moss film with its roots facing down and leaves facing up on the hydrogel, allowing the hydrogel to fully wet the root part of the carbonized moss film, and then removing it after cross-linking and curing under the action of glutaraldehyde to obtain a precursor; spraying a hydrophobic modifier onto the stem and leaf surface of the precursor, and completing the surface hydrophobic modification after heat treatment.
[0006] Furthermore, the freezing process involves freezing at -25 to -10°C for 4 to 24 hours. The freezing temperature directly affects ice crystal growth; excessively high or low temperatures will hinder the growth of ice crystals to construct the porous structure within the biomass. Simultaneously, excessively long freezing times will cause the biomass structure to break down, negatively impacting the stability of the evaporator.
[0007] Furthermore, the stem and leaf density of the moss material is 0.2~0.5 g / cm³. 3 The stem length of the moss material is 1~1.5cm.
[0008] Furthermore, the carbonization process involves heating to 500-700°C at a rate of 0.5-1.5°C / min and holding at that temperature for 0.5-2 hours. The heating rate affects the strength of the fiber structure in the carbon film. Excessive heating leads to severe shrinkage of the biomass, reducing the stability of the carbon structure. Too high a carbonization temperature affects the degree of graphitization and the abundance of functional groups on the surface of the carbon material; however, too low a carbonization temperature is also detrimental to the complete carbonization of the biomass pyrolysis.
[0009] Furthermore, the concentration of polyvinyl alcohol (PVA) in the hydrogel is 0.8~1.5 g / mL; too high a PVA content will reduce the water absorption of the gel; too low a PVA content will reduce the mechanical strength of the gel. The concentration of glutaraldehyde in the hydrogel is 5~15 g / L; too low a glutaraldehyde content will reduce the cross-linking speed and stability of the gel. The mass ratio of polyvinyl alcohol to phytic acid is 1:0.5~1; too little phytic acid is not conducive to the gel's effect of inhibiting water molecule clusters; too much phytic acid will result in too many hydrogen bonds between the gel and water molecules, which will not be conducive to reducing the enthalpy of vaporization.
[0010] Furthermore, a hydrophobic modifier with a mass concentration of 1-3% was prepared by dissolving the silane coupling agent; this concentration directly affects the hydrophobicity of the stem and leaf parts of the photothermal evaporator.
[0011] Furthermore, the silane coupling agent includes one or more of 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, 3-perfluorooctylpropyltrimethoxysilane, dodecylmethyldimethoxysilane, tetradecyltriethoxysilane, n-octyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane.
[0012] Furthermore, it is heat-treated at 110~130℃ for 0.5~1.5 h.
[0013] A moss carbonization membrane-gel composite double-layer evaporator prepared by the above method includes a carbonized moss membrane obtained by carbonizing moss material; the root of the carbonized moss membrane is covered with a hydrogel layer having aromatic groups; the stem and leaf surfaces of the carbon membrane are hydrophobic.
[0014] Furthermore, the diameter of the capillaries in the stem of the carbonized moss membrane is 2~20 μm.
[0015] By adopting the above scheme, the method of the present invention has the following advantages:
[0016] 1. This invention transforms natural moss materials into carbon film materials with excellent light-harvesting and photothermal conversion capabilities through freeze-drying, carbonization, and interfacial hydrophobic modification. The hydrophobic treatment of the upper surface of the carbon film imparts good salt resistance. During photothermal evaporation, the hydrophobic three-dimensional carbon film not only serves as a photothermal conversion layer, but its retained natural porous structure also functions as a water transport channel. A polyvinyl alcohol-phytic acid (PA) gel layer constructed at the root of the carbon film, combined with the above structure, enhances the system's water transport capacity, thermal management capabilities, and mechanical strength.
[0017] 2. This invention combines natural biological structures with artificial gel technology. The hydrogel structure at the root serves as a water storage and thermal management layer, which effectively reduces heat transfer loss and enables rapid water replenishment and local thermal effects at the evaporation interface. At the same time, the gel layer also acts as a fixation layer for the carbon film, enhancing the mechanical strength and durability of the photoevaporator. In addition, the hydrogen bond structure inside the hydrogel inhibits the formation of water molecule clusters, which helps to reduce the enthalpy of vaporization.
[0018] 3. This invention utilizes hydrogel to mimic the water storage and heat management functions of soil, possessing the functions of rapid self-water absorption and mitigating heat loss. At the same time, the hydrogel layer also plays a role in protecting the stability of the vegetation carbon film structure, enhancing the mechanical strength and stability of the overall structure.
[0019] 4. The hydrophobicity of the surface of the photoevaporator of the present invention helps to keep the photothermal conversion interface dry and clean, and inhibits salt crystallization. At the same time, the carbon fibers of the carbon film intertwined with each other have the function of re-capturing and utilizing the incident light. The two work together to enhance light capture and ensure rapid water transport.
[0020] 5. The moss-derived carbon membrane selected in this invention possesses a natural capillary porous structure and a three-dimensional fibrous structure with high space utilization, which contributes to rapid water transport and light absorption efficiency. Furthermore, its abundant functional groups and aromatic structure give it good photothermal conversion capabilities. Attached Figure Description
[0021] Figure 1 An optical image of the upper surface of the evaporator obtained in Example 1;
[0022] Figure 2 This is a cross-sectional scanning electron microscope image of the carbonized moss membrane stem obtained in Example 1;
[0023] Figure 3 This is a cross-sectional scanning electron microscope image of the carbonized moss membrane stem obtained in Example 1;
[0024] Figure 4 The image shows a scanning electron microscope (SEM) image of the carbonized moss stem obtained in Comparative Example 1.
[0025] Figure 5 The image shows the contact angle test results of the stem and leaf portion of the carbonized moss membrane prepared in Example 1.
[0026] Figure 6 The image shows the solid state of the carbonized moss membrane obtained in Example 1 after grinding the stem and leaf parts.
[0027] Figure 7 The image shows a fine Si spectrum of XPS on the surface of the stem and leaf portion of the photoevaporator prepared in Example 1.
[0028] Figure 8 Raman diagrams of the carbonized moss membranes synthesized in Example 1 and Comparative Example 2;
[0029] Figure 9 The image shows the photo-heating curve of the photoevaporator prepared in Example 1.
[0030] Figure 10 The evaporation-time curves of the photoevaporator prepared in Example 1 in NaCl solutions of different concentrations are shown.
[0031] Figure 11 The evaporation rate-salt concentration curves of the photoevaporator prepared in Example 1 in NaCl solutions of different concentrations are shown.
[0032] Figure 12For Example 1, the curves showing the seawater evaporation rate and evaporation efficiency of the photo-evaporators prepared in Comparative Examples 2 and 4 as a function of time;
[0033] Figure 13 The diagram shows the continuous evaporation rate of the photo-evaporator prepared in Example 1.
[0034] Figure 14 The evaporation rate-time curve of the photoevaporator prepared in Comparative Example 1;
[0035] Figure 15 The evaporation rate-time curve of the photo-evaporator prepared in Comparative Example 2 is shown.
[0036] Figure 16 Evaporation rate-time curve of the photo-evaporator prepared in Comparative Example 3;
[0037] Figure 17 The evaporation rate-time curve of the photo-evaporator prepared in Comparative Example 4 is shown. Detailed Implementation
[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0039] Example 1: (1) The sample was first frozen at -18 ℃ for 12 h, and then freeze-dried at -70 ℃ for 24 h; then the intact part of the sample was cut into 6×6 cm samples. Finally, the sample was heated to 600 ℃ at a rate of 1 ℃ / min under a nitrogen atmosphere and kept at the temperature for 1 h.
[0040] (2) 2 g of PVA was gradually added to 20 g of deionized water under magnetic stirring. The mixture was heated in a water bath at 45°C and stirred continuously until the PVA was completely dissolved. 1.4 g of phytic acid was weighed and dissolved in 2 mL of deionized water and added to the PVA solution. Stirring was continued for 15 min. Finally, 5 mL of glutaraldehyde solution (5 wt%) was added dropwise and stirred thoroughly before being poured into a mold. The carbonized moss membrane was then placed on the hydrogel so that the roots were completely submerged in the hydrogel and the stems and leaves were exposed. The mixture was left to stand until the hydrogel was completely solidified.
[0041] (3) Prepare a 2% (w / w) solution of 1H,1H,2H,2H-perfluorodecyltriethoxysilane using water and ethanol as a hydrophobic modifier and spray it onto the upper surface of the carbonized moss film. After the stems and leaves of the carbonized moss film are completely covered by the hydrophobic modifier, place it in a vacuum oven at 120 °C and heat for 1 h.
[0042] Figure 1 This is an optical image of the upper surface of the evaporator obtained in Example 1. Figure 1 It can be seen that long and uniform carbon fibers form an intertwined structure, and the interlaced fiber structure is conducive to improving the utilization rate of incident light by the evaporator.
[0043] Figure 2 This is a cross-sectional scanning electron microscope image of the carbonized moss membrane stem obtained in Example 1. Figure 2 As can be seen from the front view, there are obvious capillaries in the carbon fiber, with a diameter between 2 and 20 μm.
[0044] Figure 3 This is a cross-sectional scanning electron microscope image of the carbonized moss membrane stem obtained in Example 1. Figure 3 As can be seen from the side view of the fiber, the capillary runs through the inside of the fiber, which indicates that it is a complete water transport channel that can better preserve the original transpiration of the plant and thus carry out effective water transport.
[0045] Figure 5 This is a contact angle test diagram of the stem and leaf portion of the carbonized moss membrane from Example 1. (From...) Figure 5 It is evident that after hydrophobic treatment, the carbonized moss film interface exhibits significant hydrophobicity, which helps maintain its dryness and salt resistance, thus contributing to the maintenance of stable photothermal conversion capacity.
[0046] Figure 6 This is a UV image of the solid residue from the ground stems and leaves of the carbonized moss membrane in Example 1. Figure 6 As can be seen, its average absorbance is higher than 90%, which indicates that the carbon material derived from *Phyllostachys edulis* has good light absorption capacity.
[0047] Figure 7 The image shown is an XPS image of the stem and leaf portion surface of the photoevaporator in Example 1. Figure 7 It is evident that Si mainly originates from the interfacial functional groups after the FAS reagent modifies the carbon interface, which also confirms the occurrence of the functionalization modification reaction.
[0048] Figure 8 Raman blotting of the carbonized moss films prepared in Example 1 and Comparative Example 2. Figure 8 As can be seen, the carbon film in Example 1 has typical D-bands and G-bands, proving that it has a certain degree of disordered structure.
[0049] Comparative Example 1: The difference from Example 1 is that:
[0050] (1) First, freeze the moss material at -18℃ for 36 h, then freeze-dry the sample for 24 h; then cut the intact part of the sample into 6×6 cm samples; finally, heat to 800℃ at a rate of 3℃ / min under nitrogen atmosphere and keep at the temperature for 1 h.
[0051] Figure 4 This is a scanning electron microscope (SEM) image of the carbon film stem of the photoevaporator prepared in Comparative Example 1. Figure 4 It is evident that the excessively rapid heating rate and excessively high constant temperature caused significant breakage of the carbon film's nanostructure, making it unable to maintain a stable structure.
[0052] Comparative Example 2: The difference from Example 1 is that:
[0053] (3) Prepare a 0.5% (w / w) solution of 1H,1H,2H,2H-perfluorodecyltriethoxysilane using water and ethanol as a hydrophobic modifier and spray it onto the upper surface of the carbonized moss film. After the stems and leaves of the carbonized moss film are completely covered with the hydrophobic modifier, place it in a vacuum oven at 120 °C and heat for 1 h.
[0054] Figure 8 Raman images of the carbon surface of the composite films prepared in Example 1 and Comparative Example 2 are shown. Figure 8 It can be seen that both Example 1 and Comparative Example 2 have typical D-bands and G-bands, and their two peak ratios are similar, proving that the hydrophobic treatment has little effect on the lattice of the carbon film.
[0055] Comparative Example 3: The difference from Example 1 is that:
[0056] (2) 1 g of PVA was gradually added to 20 g of deionized water under magnetic stirring; the mixture was heated in a water bath at 45°C and stirred continuously until the PVA was completely dissolved; 0.6 g of phytic acid was weighed and dissolved in 2 mL of deionized water and added to the PVA solution, and stirred for 15 min; finally, 5 mL of glutaraldehyde solution (5 wt%) was added dropwise, and after stirring thoroughly, it was poured into a mold; then the carbonized moss membrane was placed on the hydrogel, so that the roots were completely submerged in the hydrogel and the stems and leaves were exposed, and left to stand until the hydrogel was completely solidified.
[0057] Comparative Example 4: The difference from Example 1 is that:
[0058] (2) 2 g of PVA was gradually added to 20 g of deionized water under magnetic stirring; the mixture was heated in a water bath at 45°C and stirred continuously until the PVA was completely dissolved; 3 g of phytic acid was weighed and dissolved in 2 mL of deionized water and added to the PVA solution, and stirred for 15 min; finally, 5 mL of glutaraldehyde solution (5 wt%) was added dropwise, and after stirring thoroughly, it was poured into a mold; then the carbonized moss membrane was placed on the hydrogel, so that the roots were completely submerged in the hydrogel and the stems and leaves were exposed, and left to stand until the hydrogel was completely solidified.
[0059] Photothermal conversion experiments of the samples in the examples and comparative examples:
[0060] In an environment with an ambient temperature of 25 ℃ and a humidity of 50%, parallel experiments were conducted on the photoevaporators prepared in the above examples and comparative examples: the prepared photoevaporators were floated on the water surface, and the samples were irradiated with a xenon lamp (PLS-SXE 300 / 300UV) to simulate sunlight. The weight loss of the evaporation system was recorded using an analytical balance, and the temperature of different samples was recorded using an infrared (IR) thermal imager (~0.4 ℃ measurement error); the water samples were distilled water and 0~20 wt% NaCl solution.
[0061] Figure 9 This is a graph showing the temperature rise curve of the photoevaporator prepared in Example 1 under illumination. Figure 9 It can be seen that under sunlight, the carbon film rapidly heats up to over 80°C within 30 seconds, indicating that it has good photothermal conversion capabilities.
[0062] Figure 10 This is an evaporation-time curve of the photoevaporator prepared in Example 1 in NaCl solutions of different concentrations. Figure 10 It can be seen that the evaporation capacity of Example 1 does not change much with the increase of salt concentration, which shows that it has a good adaptability to a wide range of salt concentrations.
[0063] Figure 11 This is a graph showing the evaporation rate versus salt concentration of the photoevaporator prepared in Example 1 in NaCl solutions of different concentrations. Figure 11 It is evident that the evaporation capacity of Example 1 did not change significantly with increasing salt concentration, confirming its good application potential.
[0064] Figure 12 The graphs show the seawater evaporation rate and evaporation efficiency over time for the photoevaporators prepared in Example 1 and Comparative Examples 2 and 4. Figure 12 It is evident that the evaporation rate and evaporation efficiency of Example 1 are significantly superior to the other two. Comparative Example 2 suffers from insufficient hydrophobicity, with the water-wetting interface hindering the utilization of light energy; while Comparative Example 4 suffers from excessive phytic acid, resulting in overly strong hydrogen bonds between it and water, which hinders the reduction of enthalpy of vaporization.
[0065] Figure 13 This is a graph showing the continuous evaporation rate of the photo-evaporator prepared in Example 1. Figure 13 It can be seen that the light evaporator prepared in Example 1 did not show a significant decrease in evaporation performance during long-term continuous evaporation, which indicates that the evaporator has stable evaporation performance.
[0066] Figure 14 This is an evaporation rate-time curve of the photoevaporator prepared in Comparative Example 1. Figure 14 It can be seen that the evaporation rate of Comparative Example 1 is lower than that of Example 1. The main reason is that excessive freezing and high-temperature carbonization cause the capillary structure to break down, which is not conducive to water transport and reduces the evaporation efficiency.
[0067] Figure 15 This is an evaporation rate-time curve of the photoevaporator prepared in Comparative Example 2. Figure 15 It can be seen that the evaporation rate of Comparative Example 2 is lower than that of Example 1. This is because the hydrophobic treatment is insufficient, which damages the dryness of the photothermal conversion interface and is not conducive to the local thermal effect.
[0068] Figure 16 This is an evaporation rate-time curve of the photoevaporator prepared in Comparative Example 3. Figure 16 It can be seen that the evaporation rate of Comparative Example 3 is lower than that of Example 1. This is mainly because the PVA content is lower, the stability and water absorption of the gel layer are insufficient, which is not conducive to stable photothermal evaporation.
[0069] Figure 17 This is an evaporation rate-time curve of the photoevaporator prepared in Comparative Example 4. Figure 17 It can be seen that the evaporation rate of Comparative Example 4 is lower than that of Example 1. This is because there is too much phytic acid, too many hydrogen bonds between the hydrogel layer and water, and too much heat energy is used to break the hydrogen bonds, resulting in a decrease in evaporation efficiency.
[0070] The above experiments demonstrate that the hydrophobic structure of the stem and leaf portion of the photoevaporator of this invention effectively prevents water wetting interference, ensuring a clean and dry photothermal conversion interface and inhibiting salt crystallization. Its retained natural capillary structure and intertwined carbon fiber structure work synergistically to enhance light capture and ensure rapid water transport. The hydrogel layer at the bottom of the photoevaporator possesses abundant functional groups and aromatic structures, as well as low thermal conductivity, effectively reducing the enthalpy of vaporization and heat loss, thereby increasing the evaporation rate. Furthermore, the hydrogel layer significantly enhances the mechanical strength and stability of the system.
[0071] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.
Claims
1. A method for preparing a moss carbonization film-gel composite double-layer evaporator, characterized in that, Includes the following steps: The moss material was first freeze-treated and then freeze-dried; carbonized under a protective atmosphere to obtain a carbonized moss membrane; polyvinyl alcohol and phytic acid were mixed and dissolved, and glutaraldehyde was added to form a hydrogel; the carbonized moss membrane was then placed on the hydrogel with the roots facing down and the leaves facing up. After the hydrogel fully wetted the root part of the carbonized moss membrane and cross-linked and solidified under the action of glutaraldehyde, it was removed to obtain the precursor; a hydrophobic modifier was sprayed onto the stem and leaf surface of the precursor, and the surface hydrophobic modification was completed after heat treatment.
2. The method for preparing the moss carbonization film-gel composite double-layer evaporator according to claim 1, characterized in that, The freezing process involves freezing at -25 to -10°C for 4 to 24 hours.
3. The method for preparing the moss carbonization film-gel composite double-layer evaporator according to claim 1, characterized in that, The stem and leaf density of the moss material is 0.2~0.5 g / cm³. 3 The stem length of the moss material is 1~1.5cm.
4. The method for preparing the moss carbonization film-gel composite double-layer evaporator according to claim 1, characterized in that, The carbonization process involves heating to 500-700°C at a rate of 0.5-1.5°C / min and holding at that temperature for 0.5-2 hours.
5. The method for preparing the moss carbonization film-gel composite double-layer evaporator according to claim 1, characterized in that, The concentration of polyvinyl alcohol in the hydrogel is 0.8~1.5 g / mL; the concentration of glutaraldehyde in the hydrogel is 10~20 g / L; and the mass ratio of polyvinyl alcohol to phytic acid is 1:0.5~1.
6. The method for preparing the moss carbonization film-gel composite double-layer evaporator according to claim 5, characterized in that, A hydrophobic modifier with a mass concentration of 1-3% was prepared by dissolving a silane coupling agent.
7. The method for preparing the moss carbonization film-gel composite double-layer evaporator according to claim 6, characterized in that, The silane coupling agent includes one or more of 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, 3-perfluorooctylpropyltrimethoxysilane, dodecylmethyldimethoxysilane, tetradecyltriethoxysilane, n-octyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane.
8. The method for preparing the moss carbonization film-gel composite double-layer evaporator according to claim 1, characterized in that, Heat-treat at 110~130℃ for 0.5~1.5 h.
9. A moss carbonization film-gel composite double-layer evaporator prepared by the method according to any one of claims 1 to 8, characterized in that, It includes a carbonized moss membrane obtained by carbonizing moss material; the roots of the carbonized moss membrane are covered with a hydrogel layer having hydrophilic groups; the stems and leaves of the carbon membrane are hydrophobic.
10. The moss carbonization membrane gel composite double-layer evaporator according to claim 1, characterized in that, The capillary diameter in the stem of the carbonized moss membrane is 2~20 μm.