Composite photo-thermal evaporator based on lignin and nano tungsten disulfide co-assembled modified wood as well as preparation method and application of composite photo-thermal evaporator

Abstract

The invention discloses a composite photo-thermal evaporator based on lignin and nano tungsten disulfide co-assembled modified wood and a preparation method and application of the composite photo-thermal evaporator, and relates to the technical field of solar energy utilization and water treatment. The interaction (such as hydrogen bonds and the like) between regenerated lignin molecules and WS2 nanosheets is utilized, so that uniform and stable co-assembly of the regenerated lignin molecules and the WS2 nanosheets in the wood is realized. Lignin not only contributes to the photothermal effect, but also serves as a green dispersing agent to prevent agglomeration of WS2 nanosheets, and serves as a bridge to enhance the binding force of WS2 and wood fibers, so that the comprehensive photothermal performance of the composite material is remarkably improved.

Description

Technical Field

[0001] This invention relates to the fields of solar energy utilization and water treatment technology, and in particular to a composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood, its preparation method and application. Background Technology

[0002] Solar interface photothermal evaporation technology is a green and sustainable technology that utilizes solar energy to generate steam for water purification. Its core lies in developing efficient, low-cost, and stable photothermal evaporation materials. Wood, especially bleached wood, is considered an ideal substrate for photothermal evaporators due to its natural three-dimensional porous structure and directional water transport channels. However, the photothermal conversion efficiency of wood alone is limited. Currently, carbon materials and noble metal nanoparticles are often used as photothermal materials in composites, but these materials suffer from high cost, environmental unfriendliness, or limited spectral absorption range. Two-dimensional transition metal disulfides (such as WS2) have excellent photothermal properties, but the nanosheets are prone to agglomeration, affecting their performance and stable loading on the matrix. Lignin, a byproduct of the paper industry, is inexpensive, widely available, and possesses photothermal conversion capabilities, but it is usually treated as waste or low-value fuel. Currently, there is a lack of a solution that can synergistically utilize lignin and WS2 and stably and efficiently integrate them into a wood matrix to construct a high-performance photothermal evaporator. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a composite photothermal evaporator based on the co-assembly of lignin and nano-tungsten disulfide modified wood, its preparation method, and its application.

[0005] In a first aspect, the present invention proposes a method for preparing a composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood, comprising the following steps: (1) Wood was subjected to delignification and de-hemicellulose treatment in sequence, and then freeze-dried to obtain three-dimensional porous bleached wood aerogel; (2) Use an acidic eutectic solvent to extract lignin from biomass raw materials to obtain a lignin solution dissolved in DES; (3) Aqueous dispersion of nano-tungsten disulfide was prepared by ultrasonic-assisted liquid phase exfoliation; (4) Immerse the bleached wood aerogel in the lignin solution, then add nano-tungsten disulfide aqueous dispersion, stir and react, and then vacuum impregnate. (5) Take out the wood, wash it until the washing liquid is neutral, pre-freeze it and freeze dry it to obtain a composite photothermal evaporator.

[0006] Further, step (1) includes: (a) The wood is placed in an acidic oxidizing solution to react and remove lignin, resulting in wood after lignin removal; (b) The wood after lignin removal is placed in a hemicellulose removal solution to react and remove hemicellulose, resulting in wood after lignin and hemicellulose removal; (c) The wood after lignin and hemicellulose removal is washed until the washing liquid is neutral, then pre-frozen and freeze-dried to obtain bleached wood aerogel with rich pore structure.

[0007] Furthermore, the pH of the acidic oxidizing solution in step (a) is 3 to 6.

[0008] Furthermore, the acidic oxidizing solution in step (a) includes either an acetic acid-buffered NaClO2 solution or a peracetic acid system.

[0009] Furthermore, in step (a), the reaction temperature for removing lignin is 70~90℃, and the reaction time is 12~48h.

[0010] Furthermore, the hemicellulose removal solution includes one of NaOH solution, KOH solution, and acidic sodium chlorite solution.

[0011] Furthermore, the reaction to remove hemicellulose in step (b) is carried out at room temperature for 6-12 hours.

[0012] Furthermore, in step (c), the freeze-drying after pre-freezing is performed by pre-freezing at -20 to -80°C for 36 to 72 hours.

[0013] Further, step (2) includes mixing the pulverized biomass raw material with an acidic eutectic solvent and heating it to react. After the reaction is completed, the mixture is cooled and the supernatant is separated by centrifugation to obtain a DES-dissolved lignin solution.

[0014] Furthermore, the mass ratio of the biomass raw material to the acidic eutectic solvent is 1:(10~20).

[0015] Furthermore, the heating reaction is carried out at 100~120℃ for 1~3 hours.

[0016] Furthermore, the acidic eutectic solvent is obtained by mixing choline chloride and oxalate dihydrate in a molar ratio of 1:(0.8~1.2) at 70~90°C.

[0017] Further, step (3) includes adding WS2 powder to an acetic acid solution of chitosan, ultrasonically treating it in an ice-water bath, centrifuging to collect the supernatant, and removing the chitosan from the supernatant to obtain a nano-tungsten disulfide aqueous dispersion.

[0018] Furthermore, the acetic acid solution of chitosan is obtained by dissolving chitosan in an acetic acid solution with a volume fraction of 5%.

[0019] Furthermore, the ultrasonic power of the ultrasonic treatment is 300~500w, the ultrasonic time is 1~3h, and the ultrasonic is turned on for 2 seconds and off for 2 seconds during the ultrasonic process.

[0020] Further, to remove chitosan from the supernatant, a 5% (v / v) acetic acid solution is added dropwise to the supernatant to precipitate the chitosan. The mixture is then centrifuged again, and the upper dispersion is collected. This process is repeated 2-3 times to remove the chitosan.

[0021] Furthermore, in step (4), the stirring speed of the stirring reaction is 2000~4000 rpm, and the stirring time is 2~4h.

[0022] Furthermore, in step (5), the freeze-drying after pre-freezing is performed at -20~-80℃ for 24~30h.

[0023] Secondly, this invention proposes a composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood, prepared by the method proposed in the first aspect above. The composite photothermal evaporator uses bleached wood as a three-dimensional porous framework, within which regenerated lignin and nano-tungsten disulfide sheets are loaded. Under one solar irradiance, the composite photothermal evaporator achieves an evaporation rate of at least 2.0 kg / m³ for pure water. -2 h -1 The evaporation efficiency is no less than 85%.

[0024] Thirdly, the present invention proposes the application of the composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood prepared by the method proposed in the first aspect above, or the composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood proposed in the second aspect above, in seawater desalination, industrial acidic or alkaline wastewater treatment, or organic dye wastewater purification.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes the interactions (such as hydrogen bonds) between regenerated lignin molecules and WS2 nanosheets to achieve uniform and stable co-assembly of the two within wood. Lignin not only contributes to the photothermal effect itself but also acts as a green dispersant to prevent WS2 nanosheet aggregation and as a bridge to enhance the bonding force between WS2 and wood fibers, thereby significantly improving the overall photothermal performance of the composite material.

[0026] This invention uses natural wood as a base and waste biomass (lignin) as one of the functional components. The raw materials are widely available, inexpensive, and environmentally friendly, meeting the requirements of sustainable development.

[0027] The RL / WS2@BBS photothermal evaporator prepared by this invention achieves an evaporation rate of up to 2.17 kg / m³ for pure water under one solar irradiance. -2 h -1 The evaporator achieves an evaporation efficiency of 87.5%, demonstrating excellent performance. Thanks to its robust co-assembled structure, the evaporator maintained stable performance in 10 cycle experiments and maintained a flow rate above 1.48 kg m³ even in harsh environments including seawater, acid (pH=5), alkali (pH=14), and organic dye solutions. -2 h -1 Its evaporation rate demonstrates strong environmental adaptability. Attached Figure Description

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of the preparation method of a composite photothermal evaporator based on the co-assembly of lignin and nano-tungsten disulfide modified wood; Figure 2 This is a process diagram illustrating the preparation method of a composite photothermal evaporator based on the co-assembly of lignin and nano-tungsten disulfide modified wood. Figure 3 SEM image of the bleached wood aerogel prepared in Example 1; Figure 4 The Raman spectrum of the RL / WS2@BBS photothermal evaporator prepared in Example 1 is shown below. Figure 5 The image shows the EDS elemental distribution of the RL / WS2@BBS photothermal evaporator prepared in Example 1, where... Figure 5 Image (a) is a SEM image of the photothermal evaporator prepared in Example 1. Figure 5 (b) is the distribution of EDS test elements in Figure (a); Figure 6 The UV-Vis-NIR absorption spectra of the samples from Example 1, Comparative Example 1, and Comparative Example 2 are shown below. Figure 7 The samples of Example 1, Comparative Example 1, and Comparative Example 2 were tested at 1kW m -2 Surface temperature changes under light intensity and infrared thermal imaging images, among which... Figure 7 (a) in the figure represents the samples of Example 1, Comparative Example 1, and Comparative Example 2 at 1kW m -2 Temperature change curve under light intensity Figure 7 Image (b) in the image is an infrared thermal image of the sample in Comparative Example 1. Figure 7 (c) in the image is the infrared thermal image of sample 2 in Comparative Example 2. Figure 7 (d) in the figure is the infrared thermal image of the sample from Example 1; Figure 8 The image shows the hydrophilicity test results of the RL / WS2@BBS photothermal evaporator prepared in Example 1. Figure 9 The evaporator samples and pure water DSC curves from Example 1, Comparative Example 1, and Comparative Example 2 are shown. Figure 10 This is a comparison chart of the evaporator sample and pure water sample in Example 1, Comparative Example 1, and Comparative Example 2; Figure 11 The graph shows the evaporation performance curves of the RL / WS2@BBS photothermal evaporator prepared in Example 1 under different light intensities. Figure 12 The graph shows the cyclic stability test results of the RL / WS2@BBS photothermal evaporator prepared in Example 1. Figure 13 The graph shows the evaporation performance of the RL / WS2@BBS photothermal evaporator prepared in Example 1 in seawater, acid (pH=5), alkali (pH=14), and organic dye solution (50ppm). Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] The following description, in conjunction with the accompanying drawings, describes the composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood, its preparation method, and its application.

[0031] like Figure 1 and Figure 2 As shown, the preparation method of the composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood according to the present invention includes the following steps: (1) Wood was subjected to delignification and de-hemicellulose treatment in sequence, and then freeze-dried to obtain three-dimensional porous bleached wood aerogel; (2) Use an acidic eutectic solvent to extract lignin from biomass raw materials to obtain a lignin solution dissolved in DES; (3) Aqueous dispersion of nano-tungsten disulfide was prepared by ultrasonic-assisted liquid phase exfoliation; (4) Immerse the bleached wood aerogel in a lignin solution, then add nano-tungsten disulfide aqueous dispersion, stir and react, and then vacuum impregnate. (5) Take out the wood, wash it until the washing liquid is neutral, pre-freeze it and freeze dry it to obtain a composite photothermal evaporator.

[0032] Step (1) is the preparation process of three-dimensional porous bleached wood aerogel, which includes the following steps: (a) The wood is placed in an acidic oxidizing solution to react and remove lignin, resulting in wood after lignin removal; (b) The wood after lignin removal is placed in a hemicellulose removal solution to react and remove hemicellulose, resulting in wood after lignin and hemicellulose removal; (c) The wood after lignin and hemicellulose removal is washed until the washing liquid is neutral, then pre-frozen and freeze-dried to obtain bleached wood aerogel with rich pore structure.

[0033] Step (a) is a lignin removal process in which the wood is placed in an acidic oxidizing solution to react and remove lignin. In some embodiments, the pH of the acidic oxidizing solution is 3-6, and the acidic oxidizing solution includes one of an acetic acid-buffered NaClO2 solution or a peracetic acid system. The wood is a lightweight, porous wood, which may be one of balsa wood, poplar, or pine.

[0034] The peracetic acid system utilizes the strong oxidizing properties of peracetic acid (generated by the reaction of hydrogen peroxide and acetic acid) to degrade and remove lignin, making it a green and efficient method for delignification. The specific peracetic acid system can be configured using one of the following methods: Scheme A (In-situ Generation Method): Glacial acetic acid and hydrogen peroxide aqueous solution (concentration 20~30wt%) are mixed at a volume ratio of approximately 1:1, and a small amount of concentrated sulfuric acid (0.5~2wt%) is added as a catalyst. The mixture is stirred at 50~70℃ for 1~2 hours to generate peracetic acid, and then cooled to room temperature for later use. This system has high activity and high delignification efficiency.

[0035] Option B (Commercial Reagent Dilution Method): Use commercially available peracetic acid solution (usually a 15-40 wt% equilibrium solution containing peracetic acid, hydrogen peroxide, acetic acid, and water), dilute with deionized water to the desired concentration (e.g., 5-15 wt%), and adjust the pH to 3-5 with acetic acid before use. This method is simple to operate and has good repeatability.

[0036] Option C (acetic acid buffer enhancement method): Mix peracetic acid solution with a certain concentration of acetate-sodium acetate buffer solution to make the treatment system have a more stable pH environment (such as pH 4.0~5.0) while maintaining strong oxidizing properties, which helps to protect the cellulose structure and reduce excessive degradation.

[0037] In some embodiments, the mass concentration of the NaClO2 solution is 1% to 5%, preferably 2%.

[0038] In some embodiments, the reaction temperature for removing lignin is 70~90℃, preferably 80℃, and the reaction time is 12~48h, preferably 24h.

[0039] Step (b) is the process of removing hemicellulose. The wood obtained in step (a) after lignin removal is placed in a hemicellulose removal solution to react and remove hemicellulose.

[0040] In some embodiments, the hemicellulose removal solution includes one of NaOH solution, KOH solution, and acidic sodium chlorite solution. The strong base (NaOH / KOH) directly dissolves hemicellulose via saponification, while the acidic buffered sodium chlorite solution selectively breaks chemical bonds (such as glycosidic bonds) in the hemicellulose molecular chain through mild oxidation, causing its degradation and dissolution. The mass concentration of the acidic sodium chlorite solution ranges from 2% to 5%. For example, an acetate-sodium acetate buffer solution (0.1M, pH 5.8) containing 3 wt% NaClO2 can be prepared.

[0041] In some embodiments, the mass concentration of the NaOH solution or KOH solution is 5% to 10%, preferably 8%.

[0042] In some embodiments, the reaction to remove hemicellulose in step (b) is carried out at room temperature for 6 to 12 hours.

[0043] Step (c) is the post-processing procedure. First, the wood, after being deionized and free of lignin and hemicellulose, is thoroughly washed with deionized water until the washing solution is neutral. Then, the sample is pre-frozen at -20 to -80°C, followed by freeze-drying for 36 to 72 hours to obtain bleached wood aerogel (BBS) with a rich porous structure. The freeze-drying process removes ice crystals through sublimation, maintaining the porous three-dimensional framework of the material and preventing collapse.

[0044] This invention removes lignin and hemicellulose from wood by bleaching, making the wood soft and white, and opening up the microchannels and nanopores in the wood, providing superior water transport capabilities for solar evaporators.

[0045] Step (2) is the preparation process of lignin solution. Lignin is extracted from biomass raw materials using an acidic eutectic solvent to obtain a lignin solution dissolved in DES (acidic eutectic solvent). Specifically, the pulverized biomass raw materials are mixed with the acidic eutectic solvent and heated to react. After the reaction is completed, the mixture is cooled and the supernatant is separated by centrifugation to obtain a lignin solution dissolved in DES (RL).

[0046] In some embodiments, the mass ratio of biomass feedstock to acidic eutectic solvent is 1:(10~20), preferably 1:15.

[0047] In some embodiments, the reaction temperature after mixing the pulverized biomass raw material with an acidic eutectic solvent and heating the mixture is 100-120°C, and the reaction time is 1-3 hours. Within a suitable reaction temperature range, the eutectic solvent maintains a stable structure and good penetration and dissolving capabilities, effectively disrupting the internal binding forces of the biomass and promoting efficient reaction; it also avoids side reactions such as component pyrolysis, ensuring product quality and reaction economy. When the reaction temperature is too high, on the one hand, it will destroy the hydrogen bond network of the eutectic solvent, causing it to lose its stable eutectic structure and original dissolving properties; on the other hand, it may cause pyrolysis and carbonization of cellulose and hemicellulose in the biomass, not only reducing the quality and yield of the target product (lignin) but also potentially generating byproducts that contaminate the system. When the reaction temperature is too low, the molecular kinetic energy of the eutectic solvent is insufficient, making it difficult to overcome the hydrogen bonds and van der Waals forces between cellulose, hemicellulose, and lignin in the biomass, thus failing to effectively penetrate the interior of the biomass powder. This makes it difficult for the target reactions such as lignin dissolution and component separation to occur, resulting in low efficiency.

[0048] After the heating reaction is complete and the mixture is cooled, the supernatant is obtained by centrifugation. The supernatant is the lignin solution dissolved in DES. After obtaining the lignin solution dissolved in DES, the concentration of lignin in the solution is determined by ultraviolet-visible spectrophotometry or gravimetric method to ensure batch consistency.

[0049] In some embodiments, biomass powder is obtained by pulverizing biomass and passing it through a 100-mesh molecular sieve. The biomass powder includes one of walnut shell powder, wheat straw powder, corn straw powder, and sorghum straw powder.

[0050] In some embodiments, the acidic eutectic solvent is obtained by mixing choline chloride and oxalic acid dihydrate in a molar ratio of 1:(0.8~1.2) at 70~90°C. The obtained eutectic solvent remains uniform and transparent without significant precipitation after standing at room temperature for 24 hours, indicating successful preparation. This invention uses a eutectic solvent to extract lignin, enabling pretreatment of biomass powder and environmentally friendly extraction of lignin.

[0051] Step (3) is the preparation process of nano-tungsten disulfide dispersion. Nano-tungsten disulfide aqueous dispersion is prepared by ultrasonic-assisted liquid phase exfoliation method. Specifically, WS2 powder is added to the acetic acid solution of chitosan, ultrasonically treated in an ice water bath, and the supernatant is collected by centrifugation. Chitosan in the supernatant is removed to obtain nano-tungsten disulfide aqueous dispersion.

[0052] The acetic acid solution of chitosan is obtained by dissolving chitosan in a 5% (v / v) acetic acid solution, and the chitosan is dissolved in the acetic acid solution to prepare a concentration of 5~40 mg / mL.

[0053] The ultrasonic power for ultrasonic treatment is 300~500W, and the ultrasonic time is 1~3h. During the ultrasonic treatment, the ultrasonic power is turned on for 2 seconds and off for 2 seconds. Chitosan is adsorbed on the interlayer and surface of WS2 through non-covalent interactions (such as hydrogen bonding and electrostatic attraction), which helps it to be exfoliated into nanosheets in the aqueous phase.

[0054] After sonication, the mixture is centrifuged at 8000~12000 rpm for 5~15 min, and the supernatant containing the exfoliated WS2 nanosheets is collected. Chitosan in the supernatant is removed to obtain a nano-tungsten disulfide aqueous dispersion.

[0055] The process of removing chitosan from the supernatant involves adding a 5% acetic acid solution dropwise to the supernatant to precipitate the chitosan, followed by centrifugation and collection of the upper dispersion. This washing process can be repeated 2-3 times to remove most of the chitosan, ultimately yielding a nano-tungsten disulfide aqueous dispersion.

[0056] In some embodiments, the concentration of the tungsten disulfide nano-aqueous dispersion is adjusted to 0.1~0.5 g / L to obtain a stable WS2 nanosheet dispersion.

[0057] Step (4) is a co-assembly composite process in which bleached wood aerogel is immersed in a lignin solution, followed by the addition of a nano-tungsten disulfide aqueous dispersion, followed by stirring and vacuum impregnation. It is understood that the ratio of BBS, lignin, and WS2 can be optimized according to the target loading and performance, for example, by adjusting the volume or concentration of the impregnation solution.

[0058] In some embodiments, the stirring speed of the stirring reaction is 2000~4000 rpm and the stirring time is 2~4 h to allow the components to be fully mixed and initially adsorbed. Then the system is placed in a vacuum environment (about -0.1 MPa) for 10~14 h to promote the solution to fully penetrate into the porous structure of BBS aerogel.

[0059] This invention regenerates lignin (RL) dissolved in the DES system using WS2 aqueous solution, combines this with vacuum impregnation, and finally fixes the composite structure by freeze-drying, successfully synthesizing an RL / WS2@BBS solar evaporator co-assembled with lignin and nano-tungsten disulfide on bleached wood.

[0060] Step (5) is the post-processing process. The wood treated in step (4) is taken out and repeatedly washed with deionized water until the washing liquid is neutral in order to remove residual solvent and unbonded components. Then, it is pre-frozen and freeze-dried to obtain the composite photothermal evaporator.

[0061] In some embodiments, freeze-drying after pre-freezing involves pre-freezing at -20 to -80°C followed by freeze-drying for 24 to 30 hours. Freeze-drying aims to remove moisture while simultaneously fixing and exposing the composite functional structure formed by RL and WS2 within the pores of the wood, resulting in a dry, porous product.

[0062] The composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood of the present invention is prepared by the method of the present invention. The composite photothermal evaporator uses bleached wood as a three-dimensional porous framework, and regenerated lignin and nano-tungsten disulfide sheets are loaded inside the three-dimensional porous framework. Under one solar irradiance, the composite photothermal evaporator has an evaporation rate of not less than 2.0 kg m³ for pure water. -2 h -1 The evaporation efficiency is not less than 85%. The composite photothermal evaporator of the present invention can be used in seawater desalination, industrial acidic or alkaline wastewater treatment, or organic dye wastewater purification.

[0063] The present invention will now be described in detail with reference to specific embodiments.

[0064] Example 1 A 2×2×1 cm block of balsa wood was placed in an acetic acid buffered NaClO2 aqueous solution at pH 4.7 and reacted at 80°C for 24 h to remove lignin. The NaClO2 aqueous solution had a mass concentration of 2%. Then, it was treated with an 8% NaOH aqueous solution at room temperature for 9 h to remove hemicellulose. The wood, after lignin and hemicellulose removal, was thoroughly washed with deionized water until the washing solution was neutral. The sample was then pre-frozen at -40°C and subsequently freeze-dried for 48 h to obtain a bleached wood aerogel (BBS) with a rich porous structure.

[0065] Choline chloride and oxalic acid dihydrate in a 1:1 molar ratio were stirred at 80°C until a homogeneous, transparent, acidic eutectic solvent (DES) was formed. 30g of crushed corn stalks and 450g of DES were mixed at a mass ratio of 1:15 and heated at 110°C for 2 hours. After the reaction was complete, the mixture was cooled and centrifuged to obtain a lignin solution (RL) containing dissolved DES. The concentration of lignin in the solution was determined to be 22.4 mg / mL using UV-Vis spectrophotometry.

[0066] A certain amount of chitosan was dissolved in a 5% (v / v) acetic acid solution to prepare a solution with a concentration of 200 mg / mL. 0.1 g of WS2 powder was added to 100 mL of the chitosan-acetic acid solution and sonicated in an ice-water bath at a power of 400 W for 2 hours, using a 2-second on / off cycle. After sonication, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant containing the exfoliated WS2 nanosheets was collected. Then, a 5% acetic acid solution was added dropwise to the supernatant to precipitate the chitosan, followed by centrifugation again, and the upper dispersion was collected. This washing process was repeated three times to remove most of the chitosan, ultimately yielding an aqueous dispersion of tungsten disulfide nanosheets. Finally, the concentration of the tungsten disulfide nanosheet aqueous dispersion was adjusted to 0.3 g / L to obtain a stable WS2 nanosheet dispersion.

[0067] Bleached wood aerogel was immersed in 100 mL of lignin solution, followed by the addition of 300 mL of WS2 dispersion. The mixture was stirred at 3000 rpm for 3 hours and then vacuum impregnated for 12 hours.

[0068] The wood was removed and repeatedly washed with deionized water until the washing solution was neutral. Then, it was pre-frozen at -40℃ and freeze-dried for 24 hours to obtain the final RL / WS2@BBS photothermal evaporator.

[0069] Example 2 A 2×2×1 cm block of balsa wood was placed in an acetic acid buffered NaClO2 aqueous solution at pH 4.7 and reacted at 80°C for 24 h to remove lignin. The NaClO2 aqueous solution had a mass concentration of 2%. Then, it was treated with an 8% NaOH aqueous solution at room temperature for 9 h to remove hemicellulose. The wood, after lignin and hemicellulose removal, was thoroughly washed with deionized water until the washing solution was neutral. The sample was then pre-frozen at -40°C and subsequently freeze-dried for 48 h to obtain a bleached wood aerogel (BBS) with a rich porous structure.

[0070] Choline chloride and oxalic acid dihydrate in a 1:1 molar ratio were stirred at 80°C until a homogeneous, transparent, acidic eutectic solvent (DES) was formed. 30g of crushed corn stalks and 450g of DES were mixed at a mass ratio of 1:15 and heated at 110°C for 2 hours. After the reaction was complete, the mixture was cooled and centrifuged to obtain a lignin solution (RL) containing dissolved DES. The concentration of lignin in the solution was determined to be 22.4 mg / mL using UV-Vis spectrophotometry.

[0071] A certain amount of chitosan was dissolved in a 5% (v / v) acetic acid solution to prepare a solution with a concentration of 200 mg / mL. 0.1 g of WS2 powder was added to 100 mL of the chitosan-acetic acid solution and sonicated in an ice-water bath at a power of 400 W for 2 hours, using a 2-second on / 2-second off cycle. After sonication, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant containing the exfoliated WS2 nanosheets was collected. Then, a 5% acetic acid solution was added dropwise to the supernatant to precipitate the chitosan, followed by centrifugation again, and the upper dispersion was collected. This washing process was repeated three times to remove most of the chitosan, ultimately yielding an aqueous dispersion of tungsten disulfide nanosheets. Finally, the concentration of the tungsten disulfide nanosheet aqueous dispersion was adjusted to 0.1 g / L to obtain a stable WS2 nanosheet dispersion.

[0072] Bleached wood aerogel was immersed in 100 mL of lignin solution, followed by the addition of 300 mL of WS2 dispersion. The mixture was stirred at 3000 rpm for 3 hours and then vacuum impregnated for 12 hours.

[0073] The wood was removed and repeatedly washed with deionized water until the washing solution was neutral. Then, it was pre-frozen at -40℃ and freeze-dried for 24 hours to obtain the final RL / WS2@BBS photothermal evaporator.

[0074] Example 3 A 2×2×1 cm block of balsa wood was placed in an acetic acid buffered NaClO2 aqueous solution at pH 4.7 and reacted at 80°C for 24 h to remove lignin. The NaClO2 aqueous solution had a mass concentration of 2%. Then, it was treated with an 8% NaOH aqueous solution at room temperature for 9 h to remove hemicellulose. The wood, after lignin and hemicellulose removal, was thoroughly washed with deionized water until the washing solution was neutral. The sample was then pre-frozen at -40°C and subsequently freeze-dried for 48 h to obtain a bleached wood aerogel (BBS) with a rich porous structure.

[0075] Choline chloride and oxalic acid dihydrate in a 1:1 molar ratio were stirred at 80°C until a homogeneous, transparent, acidic eutectic solvent (DES) was formed. 30g of crushed corn stalks and 450g of DES were mixed at a mass ratio of 1:15 and heated at 110°C for 2 hours. After the reaction was complete, the mixture was cooled and centrifuged to obtain a lignin solution (RL) containing dissolved DES. The concentration of lignin in the solution was determined to be 22.4 mg / mL using UV-Vis spectrophotometry.

[0076] A certain amount of chitosan was dissolved in a 5% (v / v) acetic acid solution to prepare a solution with a concentration of 200 mg / mL. 0.1 g of WS2 powder was added to 100 mL of the chitosan-acetic acid solution and sonicated in an ice-water bath at a power of 400 W for 2 hours, using a 2-second on / off cycle. After sonication, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant containing the exfoliated WS2 nanosheets was collected. Then, a 5% acetic acid solution was added dropwise to the supernatant to precipitate the chitosan, followed by centrifugation again, and the upper dispersion was collected. This washing process was repeated three times to remove most of the chitosan, ultimately yielding an aqueous dispersion of tungsten disulfide nanosheets. Finally, the concentration of the tungsten disulfide nanosheet aqueous dispersion was adjusted to 0.2 g / L to obtain a stable WS2 nanosheet dispersion.

[0077] Bleached wood aerogel was immersed in 100 mL of lignin solution, followed by the addition of 300 mL of WS2 dispersion. The mixture was stirred at 3000 rpm for 3 hours and then vacuum impregnated for 12 hours.

[0078] The wood was removed and repeatedly washed with deionized water until the washing solution was neutral. Then, it was pre-frozen at -40℃ and freeze-dried for 24 hours to obtain the final RL / WS2@BBS photothermal evaporator.

[0079] Example 4 A 2×2×1 cm block of balsa wood was placed in an acetic acid buffered NaClO2 aqueous solution at pH 4.7 and reacted at 80°C for 24 h to remove lignin. The NaClO2 aqueous solution had a mass concentration of 2%. Then, it was treated with an 8% NaOH aqueous solution at room temperature for 9 h to remove hemicellulose. The wood, after lignin and hemicellulose removal, was thoroughly washed with deionized water until the washing solution was neutral. The sample was then pre-frozen at -40°C and subsequently freeze-dried for 48 h to obtain a bleached wood aerogel (BBS) with a rich porous structure.

[0080] Choline chloride and oxalic acid dihydrate in a 1:1 molar ratio were stirred at 80°C until a homogeneous, transparent, acidic eutectic solvent (DES) was formed. 30g of crushed corn stalks and 450g of DES were mixed at a mass ratio of 1:15 and heated at 110°C for 2 hours. After the reaction was complete, the mixture was cooled and centrifuged to obtain a lignin solution (RL) containing dissolved DES. The concentration of lignin in the solution was determined to be 22.4 mg / mL using UV-Vis spectrophotometry.

[0081] A certain amount of chitosan was dissolved in a 5% (v / v) acetic acid solution to prepare a solution with a concentration of 200 mg / mL. 0.1 g of WS2 powder was added to 100 mL of the chitosan-acetic acid solution and sonicated in an ice-water bath at a power of 400 W for 2 hours, using a 2-second on / off cycle. After sonication, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant containing the exfoliated WS2 nanosheets was collected. Then, a 5% acetic acid solution was added dropwise to the supernatant to precipitate the chitosan, followed by centrifugation again, and the upper dispersion was collected. This washing process was repeated three times to remove most of the chitosan, ultimately yielding an aqueous dispersion of tungsten disulfide nanosheets. Finally, the concentration of the tungsten disulfide nanosheet aqueous dispersion was adjusted to 0.4 g / L to obtain a stable WS2 nanosheet dispersion.

[0082] Bleached wood aerogel was immersed in 100 mL of lignin solution, followed by the addition of 300 mL of WS2 dispersion. The mixture was stirred at 3000 rpm for 3 hours and then vacuum impregnated for 12 hours.

[0083] The wood was removed and repeatedly washed with deionized water until the washing solution was neutral. Then, it was pre-frozen at -40℃ and freeze-dried for 24 hours to obtain the final RL / WS2@BBS photothermal evaporator.

[0084] Example 5 A 2×2×1 cm block of balsa wood was placed in an acetic acid buffered NaClO2 aqueous solution at pH 4.7 and reacted at 80°C for 24 h to remove lignin. The NaClO2 aqueous solution had a mass concentration of 2%. Then, it was treated with an 8% NaOH aqueous solution at room temperature for 9 h to remove hemicellulose. The wood, after lignin and hemicellulose removal, was thoroughly washed with deionized water until the washing solution was neutral. The sample was then pre-frozen at -40°C and subsequently freeze-dried for 48 h to obtain a bleached wood aerogel (BBS) with a rich porous structure.

[0085] Choline chloride and oxalic acid dihydrate in a 1:1 molar ratio were stirred at 80°C until a homogeneous, transparent, acidic eutectic solvent (DES) was formed. 30g of crushed corn stalks and 450g of DES were mixed at a mass ratio of 1:15 and heated at 110°C for 2 hours. After the reaction was complete, the mixture was cooled and centrifuged to obtain a lignin solution (RL) containing dissolved DES. The concentration of lignin in the solution was determined to be 22.4 mg / mL using UV-Vis spectrophotometry.

[0086] A certain amount of chitosan was dissolved in a 5% (v / v) acetic acid solution to prepare a solution with a concentration of 200 mg / mL. 0.1 g of WS2 powder was added to 100 mL of the chitosan-acetic acid solution and sonicated in an ice-water bath at a power of 400 W for 2 hours, using a 2-second on / off cycle. After sonication, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant containing the exfoliated WS2 nanosheets was collected. Then, a 5% acetic acid solution was added dropwise to the supernatant to precipitate the chitosan, followed by centrifugation again, and the upper dispersion was collected. This washing process was repeated three times to remove most of the chitosan, ultimately yielding an aqueous dispersion of tungsten disulfide nanosheets. Finally, the concentration of the tungsten disulfide nanosheet aqueous dispersion was adjusted to 0.5 g / L to obtain a stable WS2 nanosheet dispersion.

[0087] Bleached wood aerogel was immersed in 100 mL of lignin solution, followed by the addition of 300 mL of WS2 dispersion. The mixture was stirred at 3000 rpm for 3 hours and then vacuum impregnated for 12 hours.

[0088] The wood was removed and repeatedly washed with deionized water until the washing solution was neutral. Then, it was pre-frozen at -40℃ and freeze-dried for 24 hours to obtain the final RL / WS2@BBS photothermal evaporator.

[0089] Comparative Example 1 A 2×2×1 cm block of balsa wood was placed in an acetic acid buffered NaClO2 aqueous solution at pH 4.7 and reacted at 80°C for 24 h to remove lignin. The NaClO2 aqueous solution had a mass concentration of 2%. Then, it was treated with an 8% NaOH aqueous solution at room temperature for 9 h to remove hemicellulose. The wood, after lignin and hemicellulose removal, was thoroughly washed with deionized water until the washing solution was neutral. The sample was then pre-frozen at -40°C and subsequently freeze-dried for 48 h to obtain a bleached wood aerogel (BBS) with a rich porous structure.

[0090] Comparative Example 2 A 2×2×1 cm block of balsa wood was placed in an acetic acid buffered NaClO2 aqueous solution at pH 4.7 and reacted at 80°C for 24 h to remove lignin. The NaClO2 aqueous solution had a mass concentration of 2%. Then, it was treated with an 8% NaOH aqueous solution at room temperature for 9 h to remove hemicellulose. The wood, after lignin and hemicellulose removal, was thoroughly washed with deionized water until the washing solution was neutral. The sample was then pre-frozen at -40°C and subsequently freeze-dried for 48 h to obtain a bleached wood aerogel (BBS) with a rich porous structure.

[0091] A certain amount of chitosan was dissolved in a 5% (v / v) acetic acid solution to prepare a solution with a concentration of 200 mg / mL. 0.1 g of WS2 powder was added to 100 mL of the chitosan-acetic acid solution and sonicated in an ice-water bath at a power of 400 W for 2 hours, using a 2-second on / off cycle. After sonication, the mixture was centrifuged at 10000 rpm for 10 min, and the supernatant containing the exfoliated WS2 nanosheets was collected. Then, a 5% acetic acid solution was added dropwise to the supernatant to precipitate the chitosan, followed by centrifugation again, and the upper dispersion was collected. This washing process could be repeated 2-3 times to remove most of the chitosan, ultimately obtaining an aqueous dispersion of tungsten disulfide nanosheets. Finally, the concentration of the tungsten disulfide nanosheet aqueous dispersion was adjusted to 0.35 g / L to obtain a stable WS2 nanosheet dispersion.

[0092] The bleached wood aerogel was directly immersed in 300 mL of WS2 dispersion, stirred at 3000 rpm for 3 hours, and then vacuum impregnated for 12 hours.

[0093] The wood was removed and repeatedly washed with deionized water until the washing solution was neutral. Then, it was pre-frozen at -40℃ and freeze-dried for 24 hours to obtain the final WS2@BBS photothermal evaporator.

[0094] Experimental Example 1 The bleached wood aerogel (BBS) prepared in Example 1 was subjected to SEM testing, and the test results are as follows: Figure 3 As shown.

[0095] from Figure 3 It can be seen that bleached wood (BBS) has a rich porous structure, and its longitudinal and transverse water transfer capacity can reduce the problem of salt accumulation on the evaporator surface, thereby improving evaporation efficiency, indicating that it has great potential as an evaporator.

[0096] Experimental Example 2 Raman spectroscopy and EDS tests were performed on the RL / WS2@BBS photothermal evaporator prepared in Example 1. The test results are as follows: Figure 4 and Figure 5 As shown, where, Figure 5 Image (a) is a SEM image of the photothermal evaporator prepared in Example 1. Figure 5 Figure (b) shows the distribution of EDS test elements in Figure (a).

[0097] from Figure 4 It can be seen that 349 cm⁻¹ appears in the Raman spectrum of RL / WS2@BBS. -1 (E) 1 2g (pattern) and 418cm -1 (A) 1gThe characteristic peaks of the (mode) correspond to the in-plane vibrations of W and S atoms and the out-of-plane vibrations of S atoms in the WS2 nanosheets, respectively. Furthermore, characteristic peaks corresponding to lignin are also observed in the Raman spectrum, with the peak at 1050 cm⁻¹. -1 The characteristic peak may be attributed to OC stretching, ring deformation, and CH3 oscillation in lignin, 1330 cm⁻¹ -1 and 2930cm -1 These correspond to the bending vibration of phenolic hydroxyl groups in lignin and the stretching vibration of aliphatic CH groups in the lignin side chain, respectively.

[0098] from Figure 5 It can be seen that S and W elements are evenly distributed on the microchannel walls of bleached wood, which further illustrates that WS2 was successfully loaded onto wood aerogel.

[0099] Experimental Example 3 The evaporator samples from Example 1, Comparative Example 1, and Comparative Example 2 were subjected to UV-Vis-NIR absorption spectroscopy measurements. The method used was a UV-Vis-NIR spectrophotometer with an integrating sphere, employing the BaSO4 pellet method to measure the diffuse reflectance spectrum of the samples in the 250-2500 nm wavelength range, and the absorbance was calculated using the formula A=1-R. The test results are as follows: Figure 6 As shown.

[0100] according to Figure 6 It can be seen that, compared with pure BBS aerogel, due to the addition of RL and WS2 with photothermal conversion capabilities, the light absorption efficiency of WS2@BBS and RL / WS2@BBS is greater than 95%, and RL / WS2@BBS is more efficient than WS2@BBS.

[0101] Test Example 4 The evaporator samples from Example 1, Comparative Example 1, and Comparative Example 2 were subjected to a 1kW m³ test. -2 Photothermal properties under light intensity were tested and analyzed by infrared thermal imaging. The test results are as follows: Figure 7 As shown.

[0102] according to Figure 7 It can be seen that the surface temperatures of BBS, WS2@BBS, and RL / WS2@BBS reached a maximum of 24.6℃, 55.5℃, and 61.2℃ respectively within 10 minutes and remained stable, indicating that RL / WS2@BBS has good photothermal conversion capabilities. This also intuitively demonstrates that the RL / WS2@BBS solar evaporator prepared by the lignin and WS2 co-assembly strategy has better photothermal conversion performance than the WS2@BBS solar evaporator prepared by WS2 alone.

[0103] Experimental Example 5 The hydrophilicity of the RL / WS2@BBS evaporator in Example 1 was evaluated, and the evaluation results are as follows: Figure 8 As shown.

[0104] from Figure 8 It can be seen that the RL / WS2@BBS aerogel rapidly absorbed water droplets within 70 milliseconds, indicating that the wood aerogel retains the anisotropic structure of wood, and the microchannels are highly oriented along the fiber direction, enabling directional and rapid water transport.

[0105] Experimental Example 6 The enthalpy change of water during evaporation was tested on the evaporator samples from Example 1, Comparative Example 1, and Comparative Example 2, as well as pure water. The test results are as follows: Figure 9 As shown in Table 1.

[0106] Table 1:

[0107] according to Figure 9 As shown in Table 1, the enthalpy of vaporization of water itself and the enthalpy of vaporization on BBS, WS2@BBS, and RL / WS2@BBS are 2309, 1917, 1355, and 1084 J g, respectively. -1 This may be due to factors such as enhanced local heat conduction, optimized moisture output, and reduced heat loss, which also lay the foundation for achieving efficient photothermal evaporation.

[0108] Experimental Example 7 The photothermal evaporation performance of the evaporator samples and pure water samples from Examples 1, 1, and 2 was tested, and the test results are as follows: Figure 10 As shown.

[0109] from Figure 10 It can be seen that the water evaporation rates of BBS, WS2@BBS, and RL / WS2@BBS are 0.93, 1.66, and 2.17 kg m³, respectively. -2 h -1 This is likely because the synergistic effect of the interface between lignin and nano-tungsten disulfide significantly improves the photothermal evaporation performance of the evaporator. Meanwhile, the evaporation efficiency of RL / WS2@BBS aerogel is approximately 87.5%, higher than that of pure water (approximately 14.5%), BBS (approximately 35.73%), and WS2@BBS (approximately 66.0%).

[0110] Experimental Example 8 The evaporator sample prepared in Example 1 was subjected to tests on the change in the mass of evaporated water under different irradiation intensities. The test results are as follows: Figure 11 As shown.

[0111] The evaporator sample prepared in Example 1 was subjected to a mass change test after 10 cycles of evaporation. The test results are as follows: Figure 12 As shown.

[0112] according to Figure 11 It can be seen that the evaporation rate of RL / WS2@BBS aerogel gradually increases with increasing light intensity, from 2.17 kg m³. -2 h -1 (1 unit of solar radiation intensity) increased to 6.57 kg m -2 h -1 (4 solar radiation intensities).

[0113] according to Figure 12 It can be seen that the evaporation of RL / WS2@BBS aerogel remains basically constant over 10 cycles under one solar irradiance, which further proves its potential for sustainable practical application.

[0114] Experimental Example 9 The evaporator sample prepared in Example 1 was tested for evaporation performance in seawater, acid (pH=5), alkali (pH=14), and organic dye solution (50ppm). The test results are as follows: Figure 13 As shown.

[0115] according to Figure 13 It can be seen that, compared with the pure water experiment discussed in Example 7 above, the evaporation rates in the four unconventional solution environments all decreased to varying degrees, but all remained at 1.48 kg·m³. -2 ·h -1 The above are the water evaporation rates. The evaporation rate decreases most significantly in acidic solutions, likely because strong acids cause the most corrosion and damage to the photothermal materials and water channel structure. Although the evaporator's effectiveness decreases in extreme environments, its good evaporation performance is still suitable for solar photothermal water purification.

[0116] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms may refer to different embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0117] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0118] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing a composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood, characterized in that, Includes the following steps: (1) Wood was subjected to delignification and de-hemicellulose treatment in sequence, and then freeze-dried to obtain three-dimensional porous bleached wood aerogel; (2) Use an acidic eutectic solvent to extract lignin from biomass raw materials to obtain a lignin solution dissolved in DES; (3) Aqueous dispersion of nano-tungsten disulfide was prepared by ultrasonic-assisted liquid phase exfoliation; (4) Immerse the bleached wood aerogel in the lignin solution, then add nano-tungsten disulfide aqueous dispersion, stir and react, and then vacuum impregnate. (5) Remove the wood, wash it until the washing liquid is neutral, pre-freeze it, and then freeze-dry it to obtain a composite photothermal evaporator. Step (1) includes: (a) The wood is placed in an acidic oxidizing solution to react and remove lignin, resulting in wood after lignin removal; (b) The wood after lignin removal is placed in a hemicellulose removal solution to react and remove hemicellulose, resulting in wood after lignin and hemicellulose removal; (c) The wood after lignin and hemicellulose removal is washed until the washing liquid is neutral, then pre-frozen and freeze-dried to obtain bleached wood aerogel with rich pore structure.

2. The method as described in claim 1, characterized in that, The pH of the acidic oxidizing solution in step (a) is 3 to 6; And / or, the acidic oxidizing solution in step (a) includes either an acetic acid-buffered NaClO2 solution or a peracetic acid system; And / or, the reaction temperature for removing lignin in step (a) is 70~90℃, and the reaction time is 12~48h; And / or, the hemicellulose removal solution includes one of NaOH solution, KOH solution, and acidic sodium chlorite solution; And / or, the reaction to remove hemicellulose in step (b) is carried out at room temperature for 6-12 hours; And / or, in step (c), the freeze-drying after pre-freezing is performed at -20 to -80°C for 36 to 72 hours.

3. The method as described in claim 1, characterized in that, Step (2) includes mixing the crushed biomass raw material with an acidic eutectic solvent and heating it to react. After the reaction is completed, the mixture is cooled and the supernatant is separated by centrifugation to obtain a DES-dissolved lignin solution.

4. The method as described in claim 3, characterized in that, The mass ratio of the biomass raw material to the acidic eutectic solvent is 1:(10~20). And / or, the heating reaction is carried out at 100~120°C for 1~3 hours; And / or, the acidic eutectic solvent is obtained by mixing choline chloride and oxalate dihydrate in a molar ratio of 1:(0.8~1.2) at 70~90°C.

5. The method as described in claim 1, characterized in that, Step (3) includes adding WS2 powder to an acetic acid solution of chitosan, ultrasonically treating it in an ice-water bath, centrifuging to collect the supernatant, and removing the chitosan from the supernatant to obtain a nano-tungsten disulfide aqueous dispersion.

6. The method as described in claim 5, characterized in that, The acetic acid solution of chitosan is obtained by dissolving chitosan in a 5% (v / v) acetic acid solution; And / or, the ultrasonic power of the ultrasonic treatment is 300~500w, the ultrasonic time is 1~3h, and the ultrasonic is turned on for 2 seconds and off for 2 seconds during the ultrasonic process; And / or, to remove chitosan from the supernatant, add a 5% (v / v) acetic acid solution to the supernatant to precipitate the chitosan, centrifuge again, collect the upper dispersion, and repeat 2-3 times to remove the chitosan.

7. The method as described in claim 1, characterized in that, The stirring speed in step (4) is 2000~4000 rpm and the stirring time is 2~4h; And / or, in step (5), the freeze-drying after pre-freezing is performed at -20~-80℃ for 24~30h.

8. A composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood, characterized in that, Prepared by the method according to any one of claims 1 to 7, the composite photothermal evaporator uses bleached wood as a three-dimensional porous framework, and loads regenerated lignin and nano-tungsten disulfide sheets inside the three-dimensional porous framework; under one solar irradiance, the composite photothermal evaporator has an evaporation rate of not less than 2.0 kg m³ for pure water. -2 h -1 The evaporation efficiency is no less than 85%.

9. The composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood prepared by the method of any one of claims 1 to 7, or the composite photothermal evaporator based on lignin and nano-tungsten disulfide co-assembled modified wood as described in claim 8, is used in seawater desalination, industrial acidic or alkaline wastewater treatment, or organic dye wastewater purification.

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