A high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, its preparation and application

Abstract

This invention discloses a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, its preparation, and its application. The evaporator comprises an evaporator body and a heat insulation layer. The evaporator body is made of wood-based material. The wood-based material undergoes sequential treatments including lignin removal, high-temperature carbonization, superhydrophilic modification, and soaking in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate to obtain a highly efficient salt-removing, superhydrophilic carbonized porous wood sponge. The heat insulation layer is tightly attached to the lower end face of the evaporator and is externally wrapped with a water-absorbing material. This invention improves solar energy utilization and reduces salt deposition on the evaporator surface by altering its structure and surface properties, resulting in an evaporator with a higher evaporation rate.

Description

Technical Field

[0001] This invention relates to the field of photothermal evaporation materials technology, specifically to a high-efficiency salt-removing superhydrophilic carbonized wood-based solar evaporator and its preparation and application, and more specifically to a solar salt-removing interface evaporator that can achieve high-efficiency solar water evaporation while avoiding salt deposition, its preparation method and application. Background Technology

[0002] Against the backdrop of global recommendations for clean energy use and escalating water scarcity, solar-powered seawater desalination technology has emerged as a crucial direction for addressing the freshwater crisis. Traditional seawater desalination relies on fossil fuels, resulting in high costs and environmental pollution. Solar energy, as a clean and widely available renewable energy source, can significantly reduce desalination costs and carbon emissions. Currently, solar desalination accounts for an increasingly large share of the global seawater desalination market, and its utilization rate is steadily improving, becoming a major trend in combining renewable energy with seawater desalination.

[0003] Patent CN 119192660 B discloses a method for preparing and applying a sandwich-type solar-driven interface evaporator. It constructs a sandwich-type wetting gradient aerogel with a hydrophilic-hydrophobic-hydrophilic structure. The method involves spraying molybdenum disulfide, a two-dimensional material with high photothermal conversion efficiency, onto the upper surface of a porous electrospun polyimide aerogel, and then hydrophilically treating the bottom surface of the superhydrophobic three-dimensional polyimide aerogel to facilitate the supply and transport of moisture. Patent CN 116924522 B discloses a hydrophilic-hydrophobic integrated membrane material for seawater desalination and its preparation method. The method involves coating both sides of a substrate with hydrophilic and hydrophobic water solutions, placing the coated substrate in a plasma reactor, introducing carrier gas, adjusting power parameters to induce discharge, and obtaining the seawater desalination membrane material for seawater desalination. Patent CN 120664632 A discloses a conical solar interface evaporator with high salt resistance. This evaporator includes a hydrophobic heat insulation layer, a hydrophobic fixing layer, a water-absorbing layer, and a hydrophobic porous evaporation layer. The water-absorbing layer utilizes its hydrophilic properties to accelerate water absorption and improve evaporation efficiency. The hydrophilic layer, positioned between the hydrophobic porous evaporation layer and the hydrophobic fixing layer, further enhances evaporation efficiency. However, the aforementioned evaporators or seawater desalination methods do not solve the problem of salt deposition on the material surface during seawater evaporation. Salt deposition on the surface can clog the material pores, affecting the subsequent evaporation process and thus the evaporation rate. Therefore, the salt deposited on the surface during evaporation needs to be cleaned. On the other hand, the evaporators do not focus on reducing heat loss when the evaporator is exposed to sunlight. These factors will all affect economic efficiency.

[0004] Therefore, evaporators that can reduce salt deposition on the evaporator surface and achieve higher evaporation rates need to be developed. Summary of the Invention

[0005] The present invention aims to overcome the above-mentioned defects and provide an evaporator that improves solar energy utilization by changing its structure and surface properties and can reduce salt deposition on the evaporator surface to achieve a higher evaporation rate.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a high-efficiency salt-removing, super-hydrophilic carbonized wood-based solar evaporator, characterized in that it comprises an evaporator body and a heat insulation layer;

[0008] The main body of the evaporator is made of wood-based material;

[0009] The wood-based material is subjected to a series of processes including lignin removal, high-temperature carbonization, superhydrophilic modification, and soaking in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate to obtain a superhydrophilic carbonized porous wood sponge with high salt removal efficiency.

[0010] The insulation layer is attached tightly to the lower end face of the evaporator and is wrapped with water-absorbing material on the outside.

[0011] Furthermore, the present invention provides a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized in that:

[0012] The chemical reagent used for lignin removal is a mixed solution of sodium hydroxide and sodium sulfite;

[0013] The molar concentration of sodium hydroxide is 2.5 mol / L.

[0014] The molar concentration of sodium sulfite is 0.4 mol / L;

[0015] The treatment conditions are: soaking at a temperature of 50-80℃ for 4-6 hours.

[0016] Furthermore, the present invention provides a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized in that:

[0017] The high-temperature carbonization process is performed at 400-600℃ for 2.5-3 hours.

[0018] Furthermore, the present invention provides a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized in that:

[0019] The superhydrophilic modified materials are dopamine and diethylenetriamine;

[0020] The mass concentration of dopamine is 0.2-0.3 wt%, and the mass concentration of diethylenetriamine is 0.2-0.3 wt%.

[0021] Furthermore, the present invention provides a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized in that:

[0022] The immersion treatment with polydiallyldimethylammonium chloride and sodium polystyrene sulfonate was carried out by sequentially and alternately immersing polydiallyldimethylammonium chloride and sodium polystyrene sulfonate.

[0023] The concentration of polydiallyldimethylammonium chloride is 0.05-0.3 g / L, the concentration of sodium polystyrene sulfonate is 0.05-0.3 g / L, and the soaking time is 0.5-1 h each time.

[0024] Furthermore, the present invention provides a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized in that:

[0025] The absorbent material is spunlace nonwoven fabric;

[0026] The spunlace nonwoven fabric is alternately soaked in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate.

[0027] Furthermore, the present invention provides a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized in that:

[0028] In the alternating immersion treatment of spunlace nonwoven fabric with polydiallyldimethylammonium chloride and sodium polystyrene sulfonate, the concentration of polydiallyldimethylammonium chloride is 0.05-0.3 g / L, the concentration of sodium polystyrene sulfonate is 0.05-0.3 g / L, and the immersion time for each time is 0.5-1 h.

[0029] Furthermore, the present invention provides a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized in that:

[0030] The insulation layer is higher than the evaporator body.

[0031] Furthermore, the present invention provides a method for preparing a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized by comprising the following steps:

[0032] S1: After cutting the balsa wood material into wood chips of the target shape, soak the balsa wood chips in a mixed solution of sodium hydroxide and sodium sulfite to remove lignin;

[0033] S2: Soak the wood-based material after soaking in step S1 in anhydrous ethanol to remove the residual alkaline solution inside the wood, and then soak it in distilled water. After soaking, blow it dry so that the surface is dry.

[0034] S3: The wood-based material obtained in step S2 is subjected to high-temperature carbonization treatment;

[0035] S4: The carbonized wood-based material obtained in step S3 is placed in a mixed solution of dopamine and diethylenetriamine. The wood is superhydrophilic by depositing a polydopamine coating on the surface of the carbonized wood. After that, it is washed with deionized water and dried to make the surface dry.

[0036] S5: The superhydrophilic carbonized wood-based material obtained in step S4 is repeatedly and alternately immersed in a solution of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate, and then dried.

[0037] S6: Cut polypropylene plastic foam material of suitable volume according to the size of the superhydrophilic carbonized wood-based material;

[0038] S7: Cut a spunlace nonwoven fabric with an appropriate area according to the volume of the insulation layer obtained in step S6, and soak the spunlace nonwoven fabric in a solution of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate in sequence and then let it air dry naturally.

[0039] S8: Wrap the spunlace nonwoven fabric obtained in step S7 around the outside of the insulation layer, wrapping it from top to bottom. Place the insulation material below the wood-based material in the evaporator, so that the upper end of the water-absorbing material is in direct contact with the wood-based material and the lower end is in contact with the water. This combination yields a highly efficient salt-removing, super-hydrophilic carbonized wood-based solar evaporator.

[0040] In addition, the present invention also provides the application of the above-mentioned high-efficiency salt-removing superhydrophilic carbonized wood-based solar evaporator in seawater desalination.

[0041] The function and effects of this invention:

[0042] The raw material used in this invention is balsa wood. As a natural and renewable material, balsa wood is widely available and inexpensive, which provides convenient conditions for related research or production.

[0043] In addition, the high-efficiency salt-removing superhydrophilic carbonized wood-based solar evaporator of the present invention has a clear hierarchical structure, a simple and easy assembly process, and a relatively low production cost, which provides a strong guarantee for large-scale application.

[0044] In addition, the preparation method of the high-efficiency salt-removing superhydrophilic carbonized wood-based solar evaporator of the present invention, through simple chemical modification and physical deposition process, enables wood to obtain excellent hydrophilicity and photothermal conversion ability, providing an efficient and feasible technical path for low-cost and large-scale production of solar evaporators.

[0045] In addition, the high-efficiency salt-removing three-dimensional multi-stage irregularly shaped solar evaporator provided by this invention innovatively constructs a polydiallyldimethylammonium chloride / sodium polystyrene sulfonate polyelectrolyte network on the surface of wood. This network adopts the synergistic effect of Donnan balance and nanopores. The positively charged polydiallyldimethylammonium chloride layer efficiently repels divalent cations, and the precise nanoscale pore size is used to sieve ions with different hydration radii. The dual mechanism significantly reduces the salinity of the water absorption layer, thereby effectively preventing scale formation on the evaporator surface and ensuring long-term stable operation, which has good application prospects.

[0046] Specifically, the high-efficiency salt-removing three-dimensional multi-stage irregularly shaped solar evaporator provided by this invention absorbs water from the water body at the bottom of the device through a water-absorbing layer. The water is distributed on the spunlace nonwoven fabric material of the water-absorbing layer, thus transferring the water from the water body at the bottom of the device. The water-absorbing layer draws the water up, allowing it to come into contact with the circular, superhydrophilic carbonized wood above the water-absorbing layer, thus providing the necessary spatial conditions for water evaporation.

[0047] Furthermore, the absorbent layer is a spunlace nonwoven fabric layer that has been treated with polydiallyldimethylammonium chloride and sodium polystyrene sulfonate. After being soaked in the polydiallyldimethylammonium chloride and sodium polystyrene sulfonate solution, the spunlace nonwoven fabric forms a polyelectrolyte network on its surface. Through charge repulsion and ion size sieving effects, a large number of ions in the water are screened out before they enter the wood matrix for evaporation, thus greatly reducing the amount of salt precipitated from the wood matrix surface.

[0048] Furthermore, the wood-based material of this invention achieves high salt expulsion properties through multiple treatments. The surface is alternately deposited with polydiallyldimethylammonium chloride and sodium polystyrene sulfonate to form a multi-layered polyelectrolyte network. This multi-layered network construction method improves the surface film coverage and makes the water transport channels more stable. At the same time, the abundant charged groups in the film can regulate the migration and distribution of salt ions, thereby reducing the amount of salt entering the evaporator and weakening the precipitation of salt on the evaporation surface. This greatly improves the durability and functionality of the surface film and makes the evaporation process of the evaporator more stable. Attached Figure Description

[0049] Figure 1 A schematic diagram of a highly efficient salt-removing, super-hydrophilic carbonized wood-based solar evaporator;

[0050] Figure 2 This is a schematic diagram of a carbonized wood specimen.

[0051] Figure 3 Flowchart of a method for preparing a highly efficient salt-removing, superhydrophilic carbonized wood-based solar evaporator; Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but these are not intended to limit the scope of the invention.

[0053] like Figure 1 As shown, this embodiment provides a high-efficiency salt-removing, super-hydrophilic carbonized wood-based solar evaporator, comprising an evaporator body and a heat insulation layer;

[0054] The main body of the evaporator is made of wood-based material; preferably, balsa wood is used. This type of wood has a honeycomb-like microstructure, containing a large number of cell walls and pores. The natural cellulose skeleton gives it excellent water absorption properties and provides natural channels for water transport. In addition, balsa wood has low density, which reduces the overall weight of the evaporation system while also having good buoyancy, allowing it to float naturally on the water surface, providing favorable conditions for the smooth operation of the water absorption and evaporation process.

[0055] The wood-based material needs to undergo sequential processes including lignin removal, high-temperature carbonization, superhydrophilic modification, and immersion in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate to obtain a highly efficient salt-removing superhydrophilic carbonized porous wood sponge, such as... Figure 3 As shown, the specific process is as follows:

[0056] S1: After cutting the balsa wood material into wood chips of the target shape, soak the balsa wood chips in a mixed solution of sodium hydroxide and sodium sulfite to remove lignin;

[0057] The chemical reagent used for the lignin removal treatment was a mixed solution of sodium hydroxide with a molar concentration of 2.5 mol / L and sodium sulfite with a molar concentration of 0.4 mol / L; the treatment conditions were: soaking at a temperature of 50-80℃ for 4-6 hours.

[0058] In some experimental cases, it was found that when the concentrations of sodium hydroxide and sodium sulfite in the mixed solution were below 2.5 mol / L and below 0.4 mol / L, although higher concentrations of both led to more complete removal of lignin from the wood and easier formation of a porous water-conducting framework, they also caused excessive damage to the cell wall structure, resulting in decreased strength and a looser structure of the wood framework, which was detrimental to the long-term stable water absorption and transport of the evaporator. Therefore, considering both the effectiveness of lignin removal and the integrity of the porous framework structure, a sodium hydroxide concentration of 2.5 mol / L and a sodium sulfite concentration of 0.4 mol / L were considered the optimal choices.

[0059] S2: Soak the wood-based material after soaking in step S1 in anhydrous ethanol to remove the residual alkaline solution inside the wood, and then soak it in distilled water. After soaking, blow it dry so that the surface is dry.

[0060] S3: The wood-based material obtained in step S2 is subjected to high-temperature carbonization treatment. The carbonization process forms a carbonized layer on the surface of the wood, which gives the material a wider light absorption band and enhances its light absorption. At the same time, carbonization can decompose the organic carbohydrates in the wood, giving the material anti-mildew properties and improving its stability. The high-temperature carbonization treatment conditions are: heating at 400-550℃ for 2.5-3 hours.

[0061] In some experimental cases, we found that when the carbonization temperature was below 400℃, carbonization was incomplete, and the light absorption capacity was not as good as at 500℃. Above 500℃, the results at 550℃ were similar to those at 500℃, but the strength of the wood was affected at temperatures above 550℃, which was detrimental to the subsequent preparation of the evaporator. From the perspectives of economic energy consumption and efficiency, a carbonization temperature of 500℃ is the optimal choice.

[0062] S4: The carbonized wood-based material obtained in step S3 is placed in a mixed solution of dopamine and diethylenetriamine. The wood is superhydrophilic by depositing a polydopamine coating on the surface of the carbonized wood. After that, it is washed with deionized water and dried to make the surface dry.

[0063] In this embodiment, a polydopamine coating is formed on the surface of carbonized wood through an oxidative self-polymerization reaction of dopamine and diethylenetriamine. Diethylenetriamine provides an alkaline environment to promote the oxidation of dopamine to polydopamine. Polydopamine molecules are rich in phenolic hydroxyl and amino groups, achieving uniform coating by forming hydrogen bonds, van der Waals forces, and covalent bonds with the hydroxyl and amino groups on the wood matrix surface. The polydopamine coating increases the surface contact area of ​​the carbonized wood, enhances the interaction between water molecules and the surface, and introduces a large number of hydrophilic groups while maintaining the microscopic channel structure of the carbonized wood, greatly improving the water absorption of the carbonized wood. High water absorption is achieved on the basis of the high light absorption rate of carbonized wood, ensuring the evaporation efficiency and photothermal conversion capacity of the wood.

[0064] The superhydrophilic modified materials are dopamine and diethylenetriamine; the mass concentration of dopamine is 0.2-0.3 wt%, and the mass concentration of diethylenetriamine is 0.2-0.3 wt%.

[0065] In some experimental cases, we found that when the concentrations of dopamine and diethylenetriamine were below 0.2 wt%, their deposition effect was poor, resulting in poor hydrophilicity modification of the wood. At this point, higher concentrations of dopamine and diethylenetriamine led to better hydrophilicity modification. However, when the concentrations of dopamine and diethylenetriamine were above 0.3 wt%, they accumulated in the hierarchical porous structure of the carbonized wood, forming a thick deposition layer that blocked the water-carrying pores, hindering water absorption by the evaporator and reducing its water absorption capacity. Therefore, from the perspective of water absorption, a dopamine and diethylenetriamine concentration of 0.2 wt% or 0.3 wt% is the optimal choice.

[0066] S5: The superhydrophilic carbonized wood-based material obtained in step S4 is repeatedly and alternately immersed in a solution of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate, and then dried.

[0067] The immersion treatment with polydiallyldimethylammonium chloride and sodium polystyrene sulfonate was carried out by immersing in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate alternately; the concentration of polydiallyldimethylammonium chloride was 0.05-0.3 g / L, the concentration of sodium polystyrene sulfonate was 0.05-0.3 g / L, and the immersion time for each time was 0.5-1 h.

[0068] The insulation layer is tightly attached to the lower surface of the evaporator and is covered with a water-absorbing material. In the preferred embodiment, the water-absorbing material is spunlace nonwoven fabric, but other materials with water-conducting and absorbing capabilities can also be used; this material also needs to undergo a salt-removal treatment. The specific method is as follows:

[0069] In some experimental examples, we found that when the concentrations of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate in this step and S7 were below 0.05 g / L, the evaporator's salt removal capacity was insufficient. When the concentrations of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate were between 0.05 and 0.3 g / L, higher concentrations resulted in better salt removal. However, when the concentrations of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate were above 0.3 g / L, the salt removal effect was similar to that at 0.3 g / L, but excessive polyelectrolytes clogged the evaporator pores, leading to a decrease in both the hydrophilicity of the evaporator and the evaporation rate. Therefore, considering both evaporation and salt removal performance, a concentration of 0.3 g / L for polydiallyldimethylammonium chloride and sodium polystyrene sulfonate is the optimal choice.

[0070] S6: Cut polypropylene plastic foam material of suitable volume according to the size of the superhydrophilic carbonized wood-based material;

[0071] S7: Cut absorbent material of appropriate area according to the volume of the insulation layer obtained in step S6, and soak the absorbent material in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate solution in sequence and then let it air dry naturally; the concentration of polydiallyldimethylammonium chloride is 0.05-0.3g / L, the concentration of sodium polystyrene sulfonate is 0.05-0.3g / L, and the soaking time is 0.5-1h each time.

[0072] S8: Wrap the water-absorbing material obtained in step S7 around the outside of the insulation layer, wrapping it from top to bottom. Place the insulation material below the wood-based material in the evaporator, so that the upper end of the water-absorbing material is in direct contact with the wood-based material and the lower end is in contact with the water. This combination yields a highly efficient salt-removing, super-hydrophilic carbonized wood-based solar evaporator.

[0073] This insulation layer separates the wood from the water, preventing direct contact and heat loss, while the absorbent layer ensures a continuous water supply to the wood without direct contact. A polydiallyldimethylammonium chloride / sodium polystyrene sulfonate polyelectrolyte network is constructed on the wood surface using a layer-by-layer self-assembly technique. This network utilizes the charge repulsion effect generated by Donnan equilibrium, selectively repelling divalent cations through the positively charged polydiallyldimethylammonium chloride layer. Simultaneously, its nanoscale porous structure enables size sieving based on the radius of hydrated ions. This dual mechanism effectively reduces the salinity of the water absorbed by the absorbent layer, significantly improving the stability and energy conversion efficiency of the evaporation process.

[0074] In the following embodiments, the foam is a cylinder with a thickness of 20 mm and a cross-sectional radius of 30 mm, and the wood chip is a cylinder with a thickness of 10 mm and a radius of 25 mm.

[0075] Preferred embodiment 1

[0076] The preparation of a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator is as follows:

[0077] S1: Cut the balsa wood material into round wood chips; soak the balsa wood chips in a mixed solution of sodium hydroxide and sodium sulfite to remove lignin;

[0078] Specifically, the selected balsa wood has a density of 0.1~0.2 g / cm³. 3 The balsa wood used in this example has a density of 0.176 g / cm³. 3 The concentration of sodium hydroxide in the mixed solution of sodium hydroxide and sodium sulfite was 2.5 mol / L, the concentration of sodium sulfite was 0.4 mol / L, the soaking time was 5 h, and the temperature was 60℃.

[0079] S2: Soak the wood material soaked in step S1 in anhydrous ethanol for 48 hours to remove the residual alkaline solution inside the wood, and then soak it in distilled water for 24 hours. After soaking, use a blower drying oven to dry the surface.

[0080] S3: The wood material obtained in step S2 is subjected to high-temperature carbonization at 500℃ for 1 hour to enhance the photothermal conversion ability of the wood material.

[0081] S4: Place the carbonized wood material obtained in step S3 in a mixed solution of 0.3wt% dopamine and 0.3wt% diethylenetriamine to deposit a polydopamine coating on the surface of the carbonized wood, thereby superhydrophilic modification of the wood. Then, wash it with deionized water and finally dry it in a forced-air drying oven to make its surface dry.

[0082] S5: The superhydrophilic carbonized wood material obtained in step S4 is sequentially and alternately immersed in 0.15 g / L polydiallyldimethylammonium chloride solution and 0.1 g / L sodium polystyrene sulfonate solution. First, it is immersed in polydiallyldimethylammonium chloride solution, and then in polydiallyldimethylammonium chloride solution. The polydiallyldimethylammonium chloride solution is used for a total of 5 immersions, and the sodium polystyrene sulfonate solution is used for a total of 4 immersions. Each immersion lasts for 1 hour. Then, it is dried in a forced-air drying oven.

[0083] S6: The insulation material of appropriate size can be cut according to the size of the super-hydrophilic carbonized wood material and placed under the wood material to serve as an insulation layer;

[0084] S7: Cut a spunlace nonwoven fabric with an appropriate area according to the size of the insulation layer obtained in step S6 so that the spunlace nonwoven fabric can be wrapped around the outside of the insulation layer as a water-absorbing layer. Soak the spunlace nonwoven fabric in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate solution in sequence, soaking once each, and then air dry naturally after soaking for 1 hour.

[0085] S8: Wrap the spunlace nonwoven fabric obtained in step S7 around the outside of the insulation layer, wrapping it from top to bottom, with the upper end of the absorbent layer in direct contact with the wood material and the lower end in contact with the water. Then combine it with the water and the wood-based main body to obtain a highly efficient salt-removing, super-hydrophilic carbonized wood-based solar evaporator.

[0086] Comparative Example 1

[0087] A method for preparing a high-efficiency salt-removing superhydrophilic carbonized wood-based solar evaporator is basically the same as that in Example 1, except that step S5 is as follows: the superhydrophilic carbonized wood material obtained in step S4 is alternately soaked in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate solutions. First, it is soaked in polydiallyldimethylammonium chloride solution, and then soaked in polydiallyldimethylammonium chloride solution a total of 4 times and in sodium polystyrene sulfonate solution a total of 3 times. Then, it is dried using a forced-air drying oven.

[0088] Comparative Example 2

[0089] A method for preparing a high-efficiency salt-removing superhydrophilic carbonized wood-based solar evaporator is basically the same as that in Example 1, except that step S5 is as follows: the superhydrophilic carbonized wood material obtained in step S4 is alternately soaked in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate solutions. First, it is soaked in polydiallyldimethylammonium chloride solution, and then soaked in polystyrene sulfonate solution a total of 3 times and in sodium polystyrene sulfonate solution a total of 2 times. Then, it is dried using a forced-air drying oven.

[0090] Effect comparison experiment 1.

[0091] Evaporators manufactured in Example 1 and Comparative Examples 1-2 were subjected to a continuous 7-day seawater evaporation test. The procedure was as follows: an electronic balance was used to record changes in the mass of the main body water during evaporation. The system was run for 8 hours daily. By comparing the differences in evaporation rates over 7 consecutive days, the long-term evaporation effect was observed to be: Example 1 > Comparative Example 1 > Comparative Example 2.

[0092] Before the experiment, the dried evaporator was weighed. After the experiment, the evaporator was dried and weighed again. The increase in weight is the weight of the salt that entered the evaporator. The smaller the weight of the salt that entered the evaporator, the better the salt removal effect. The salt weight comparison results are: Comparative Example 2 > Comparative Example 1 > Example 1.

[0093] Effect comparison experiment 2.

[0094] Based on Example 1, Comparative Example 3 did not perform steps S1-2, Comparative Example 4 did not perform step S3, Comparative Example 5 did not perform step S4, and Comparative Example 6 did not perform steps S7-8. Evaporation effect: Example 1 was better than Comparative Examples 3-6.

[0095] Those skilled in the art will understand that, based on the prior art and the technical solutions disclosed in the above embodiments, various equivalent or modified implementation methods (hereinafter collectively referred to as "variations") can be derived. These variations do not depart from the core idea of ​​the present invention, and their specific implementation forms can be adjusted through conventional technical means; therefore, they will not be listed individually herein.

[0096] The present invention has been described in detail through the above embodiments. It should be particularly noted that the scope of protection of the present invention is not limited to the detailed structures or specific parameters described in the particular embodiments. For technical features or implementation methods not described in detail in the embodiments, it should be understood that they can be implemented using conventional technical means in the art. Any person skilled in the art can make the following adjustments to the above embodiments, provided that the essence of the technical solution of the present invention is followed: equivalent substitution of technical features, adaptive modification of implementation methods, and combined optimization of technical solutions.

[0097] The above adjustments do not affect the technical essence of the present invention, and all equivalent embodiments resulting therefrom fall within the protection scope of the present invention. The protection scope of the present invention should be determined by the claims, and not limited to the specific descriptions of the embodiments.

Claims

1. A high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator, characterized in that: Includes the evaporator body and insulation layer; The main body of the evaporator is made of wood-based material; The wood-based material is subjected to lignin removal, high-temperature carbonization, superhydrophilic modification, and soaking treatment with polydiallyldimethylammonium chloride and sodium polystyrene sulfonate in sequence to obtain a superhydrophilic carbonized porous wood sponge with high efficiency salt removal. The insulation layer is attached tightly to the lower end face of the evaporator and is wrapped with water-absorbing material on the outside.

2. The high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in claim 1, characterized in that: The chemical reagent used in the lignin removal treatment is a mixed solution of sodium hydroxide and sodium sulfite; The molar concentration of the sodium hydroxide is 2.5 mol / L; The molar concentration of the sodium sulfite is 0.4 mol / L; The treatment conditions are: soaking at a temperature of 50-80℃ for 4-6 hours.

3. The high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in claim 1, characterized in that: The high-temperature carbonization process is performed at 400-550°C for 2.5-3 hours.

4. The high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in claim 1, characterized in that: The superhydrophilic modified materials are dopamine and diethylenetriamine; The mass concentration of dopamine is 0.2-0.3 wt%, and the mass concentration of diethylenetriamine is 0.2-0.3 wt%.

5. The high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in claim 1, characterized in that: The immersion treatment of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate is carried out by sequentially and alternately immersing polydiallyldimethylammonium chloride and sodium polystyrene sulfonate. The concentration of polydiallyldimethylammonium chloride is 0.05-0.3 g / L, the concentration of sodium polystyrene sulfonate is 0.05-0.3 g / L, and the soaking time is 0.5-1 h each time.

6. The high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in claim 1, characterized in that: The absorbent material is alternately soaked in polydiallyldimethylammonium chloride and sodium polystyrene sulfonate.

7. The high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in claim 6, characterized in that: The absorbent material is subjected to alternating immersion treatment with polydiallyldimethylammonium chloride and sodium polystyrene sulfonate. The concentration of polydiallyldimethylammonium chloride is 0.05-0.3 g / L, and the concentration of sodium polystyrene sulfonate is 0.05-0.3 g / L. The immersion time for each treatment is 0.5-1 h.

8. The high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in claim 1, characterized in that: The insulation layer is higher than the evaporator body.

9. The preparation method of a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in claim 1, characterized in that, It includes the following steps: S1: After cutting the balsa wood material into wood chips of the target shape, soak the balsa wood chips in a mixed solution of sodium hydroxide and sodium sulfite to remove lignin; S2: Soak the wood-based material after soaking in step S1 in anhydrous ethanol to remove the residual alkaline solution inside the wood, and then soak it in distilled water. After soaking, blow it dry so that the surface is dry. S3: The wood-based material obtained in step S2 is subjected to high-temperature carbonization treatment; S4: The carbonized wood-based material obtained in step S3 is placed in a mixed solution of dopamine and diethylenetriamine. The wood is superhydrophilic by depositing a polydopamine coating on the surface of the carbonized wood. After that, it is washed with deionized water and dried to make the surface dry. S5: The superhydrophilic carbonized wood-based material obtained in step S4 is repeatedly and alternately immersed in a solution of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate, and then dried. S6: Cut polypropylene plastic foam material of suitable volume according to the size of the superhydrophilic carbonized wood-based material; S7: Cut water-absorbing material with an appropriate area according to the size of the heat insulation layer obtained in step S6, and soak the water-absorbing material in a solution of polydiallyldimethylammonium chloride and sodium polystyrene sulfonate in sequence, and then let it air dry naturally. S8: Wrap the water-absorbing material obtained in step S7 around the outside of the insulation layer, wrapping it from top to bottom. Place the insulation material below the wood-based material in the evaporator, so that the upper end of the water-absorbing material is in direct contact with the wood-based material and the lower end is in contact with the water. This combination yields a highly efficient salt-removing, super-hydrophilic carbonized wood-based solar evaporator.

10. The application of a high-efficiency salt-removing, superhydrophilic carbonized wood-based solar evaporator as described in any one of claims 1 to 8 in seawater desalination.

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