Wood-based porous carbon solar evaporator and preparation method

Abstract

The invention belongs to the technical field of waste wood chip derived carbon, and particularly relates to a wood-based porous carbon solar evaporator and a preparation method. The solar evaporator provided by the invention is mainly prepared from pine sawdust and carboxymethyl cellulose (CMC), and the material has excellent hydrophilicity, strong light absorption and rapid water delivery capacity. The evaporation rate under irradiation of one sun reaches 3.41 kg m <-2 > h <-1 >, and the evaporation efficiency is 93.49%. Even in a high-salt environment (20 wt% of NaCl solution), the evaporation rate can still reach 2.83 kg m <-2 > h <-1 >. Good evaporation performance is maintained in a high-salt environment, and excellent self-cleaning capability and long-term operation stability are achieved. And the preparation method is simple, convenient, economical and environment-friendly, and a new material with a wide prospect is developed for an efficient solar desalination and water purification technology.

Description

Technical Field

[0001] This invention belongs to the field of waste wood chip-derived carbon technology, specifically relating to a wood-based porous carbon solar evaporator and its preparation method. Background Technology

[0002] Global freshwater scarcity has become a major environmental problem threatening human health and social development. Industrial expansion, population growth, and extreme weather events have exacerbated the consumption and pollution of natural freshwater resources. Unconventional water resources such as seawater and brackish water, due to their high salinity or pollutant content, require treatment before use. Traditional desalination technologies, such as reverse osmosis and multi-effect distillation, can purify water, but they suffer from bottlenecks such as high energy consumption, complex equipment maintenance, and severe membrane fouling. They are particularly unsuitable for remote areas, offshore scenarios, and regions without power grid coverage. Therefore, developing low-cost, low-energy, and scalable sustainable desalination technologies is an urgent priority.

[0003] Interfacial solar steam generation (ISSG) technology, by localizing photothermal conversion at the gas-liquid interface, reduces heat loss during bulk water heating and is an ideal technological approach to address water scarcity. The core of this technology lies in the design of the evaporator material, which must simultaneously meet key performance requirements such as high solar absorption, efficient water transport, low thermal conductivity, and resistance to salt contamination. In recent years, biomass materials have become a research focus in the ISSG field due to their abundant sources, environmental friendliness, and low cost. Wood, with its naturally anisotropic porous structure (vessel diameters of tens to hundreds of micrometers and fiber channel diameters of several micrometers), low thermal conductivity, and good hydrophilicity, can achieve rapid water transport and thermal insulation, and has been widely used in evaporator fabrication. Li et al. combined high-entropy alloy nanoparticles (HEA-NPs) with balsa wood to prepare a HEA-BW composite evaporator with asymmetric wettability, achieving an evaporation rate of 2.58 kg m³ under one solar irradiation. -2 h -1 Furthermore, it maintained a concentration of 1.65 kg m³ after 10 cycles in 20 wt% high-salt water. -2 h -1 A stable evaporation rate was achieved. Jiang et al. prepared a polydopamine (PDA) / ferric oxide (Fe3O4) modified wood evaporator (PFDW) through a simple two-step in-situ growth and polymerization method. Utilizing the synergistic photothermal effect of Fe3O4 and PDA, and the vertical microporous water transport structure of the wood, it achieved a stable evaporation rate of 1.70 kg m³ under one solar irradiation. -2 h -1 The evaporation rate was high with an evaporation efficiency of 98.0%. Lu et al. prepared a wood-based evaporator (AgPW) modified with polypyrrole (PPy) and silver nanoparticles (AgNPs) through in-situ polymerization, achieving an evaporation rate of 2.04 kg m³ under one solar irradiation. -2 h -1It boasts an efficiency of 90.7% and exhibits excellent salt resistance (no salt accumulation in high-salt solutions) and long-term stability, enabling the purification of seawater, heavy metals, and organic dye wastewater. Jiao et al. demonstrated that by impregnating wood with concentrated H₂SO₄ to form a gradient carbonization structure (with a surface photothermal efficiency of 91.6% and internal retention of hydrophilic cellulose for rapid water transport), the evaporation rate reached 2.1 kg / m³ under one solar irradiation. -2 h -1 Although existing research has significantly improved the evaporation performance and salt resistance of wood-based evaporators, the cost of precious metal or high-entropy alloy nanoparticles is relatively high; at the same time, some preparation processes are complex or require treatment with strong acids or other chemical reagents, making it difficult to prepare on a large scale.

[0004] Waste wood chips are rich in cellulose, hemicellulose, and lignin, possessing a natural porous structure and abundant hydrophilic groups. They are widely available and inexpensive, making them an ideal raw material for preparing low-cost ISSG evaporators. However, wood chips are a major waste product of the wood processing industry, with a huge annual output; traditional landfill or incineration not only wastes resources but also easily causes environmental pollution. In existing research, Huang et al. prepared a polystyrene-reinforced carbon black / wood flour composite material, achieving an optimal evaporation efficiency of 80.4%. Kang et al. prepared a pine wood chip-based aerogel, achieving an evaporation rate of 3.67 kg m³ under one solar irradiation. -2 h -1 However, this wood evaporator still faces two major challenges in practical applications: first, the wood chips themselves have a loose structure and are prone to collapse when used alone, making the water transmission channels easy to become clogged; second, the evaporator is prone to salt crystal accumulation in high-salt environments, resulting in poor long-term stability. Summary of the Invention

[0005] Based on this, the present invention provides a wood-based porous carbon solar evaporator and its preparation method to solve the technical problems of the prior art, namely, the loose structure of wood chips, which are prone to collapse when used alone and the water transmission channels are prone to blockage; and the evaporator is prone to salt crystal accumulation in high-salt environments, resulting in poor stability during long-term use.

[0006] The technical solution to the above-mentioned technical problems in this application is as follows:

[0007] A method for preparing a wood-based porous carbon solar evaporator includes the following steps:

[0008] Waste wood chips were crushed and ball-milled into wood powder, then mixed evenly with sodium carboxymethyl cellulose, and compressed into tablets to obtain the precursor sample.

[0009] The precursor sample was placed in a tube furnace and carbonized in an inert gas atmosphere to obtain the waste wood chip-derived carbon material.

[0010] Preferably, in the above-mentioned method for preparing a wood-based porous carbon solar evaporator, the mass fraction of sodium carboxymethyl cellulose in the mixture of wood flour and sodium carboxymethyl cellulose is 20% to 70%.

[0011] Preferably, in the above-mentioned method for preparing a wood-based porous carbon solar evaporator, the mass fraction of sodium carboxymethyl cellulose in the mixture of wood flour and sodium carboxymethyl cellulose is 50%.

[0012] Preferably, in the above-mentioned method for preparing a wood-based porous carbon solar evaporator, the maximum particle size of the wood powder is 200 mesh.

[0013] Preferably, in the above-mentioned method for preparing the wood-based porous carbon solar evaporator, the pressure of the pressing plate is 3 to 7 MPa.

[0014] Preferably, in the above-mentioned method for preparing the wood-based porous carbon solar evaporator, the carbonization temperature is 500°C to 700°C.

[0015] Preferably, in the above-mentioned method for preparing a wood-based porous carbon solar evaporator, the carbonization time is 1 to 3 hours.

[0016] A wood-based porous carbon solar evaporator is prepared using the method described above for preparing a wood-based porous carbon solar evaporator.

[0017] Such as the above-mentioned application of wood-based porous carbon solar evaporators in the field of high-efficiency solar desalination and water purification technology.

[0018] Compared with the prior art, this application has at least the following advantages:

[0019] A wood-based porous carbon solar evaporator, primarily made from pine wood chips and carboxymethyl cellulose (CMC), possesses excellent hydrophilicity, strong light absorption, and rapid water transport capacity. The evaporation rate reaches 3.41 kgm³ under one solar irradiation. -2 h -1 The evaporation efficiency was 93.49%. Even in a high-salt environment (20 wt% NaCl solution), the evaporation rate still reached 2.83 kg m³. -2 h -1 It maintains good evaporation performance in high-salt environments and also possesses excellent self-cleaning capabilities and long-term operational stability.

[0020] This application discloses a method for preparing a wood-based porous carbon solar evaporator, which mainly includes two steps: precursor preparation and carbonization. A waste wood chip-based composite interface evaporator is prepared through a simple physical mixing-molding process. By controlling the binder, the microscopic porous structure (such as porosity and pore size distribution) and macroscopic properties (light absorption, thermal conductivity, and water transport rate) of the composite material are optimized to achieve high solar light absorption and efficient water transport. Simultaneously, the constructed porous structure inhibits salt accumulation at the evaporation interface, improving salt contamination resistance and cycle stability. Attached Figure Description

[0021] Figure 1 SEM images of Sd, SC, SS, and SP.

[0022] Figure 2 (a) TG curve; (b) porosity; (c) thermal conductivity; (d) photograph of water contact angle test; (e) 12h buoyancy test of SC.

[0023] Figure 3 (a) UV-Vis-NIR absorption spectrum and AM 1.5G spectrum solar irradiance density; (b) surface temperature of the dry evaporator under one solar irradiation; (c) change in the mass of deionized water over time during evaporation; (d) evaporation rate; (e) evaporation efficiency.

[0024] Figure 4 The following data are presented under different salt concentrations: (a) mass change curve of NaCl solution; (b) evaporation rate; (c) evaporation efficiency; (d) dissolution behavior of NaCl particles on the evaporator surface; (e) 12h continuous test; (f) evaporation rate and corresponding evaporation efficiency of methyl orange (MO), methylene blue (MB) and simulated seawater; (g) ion concentration before and after evaporation of simulated seawater; (h and i) absorbance change curves of methyl orange and methylene blue. The inset shows the color change of the solution before and after purification.

[0025] Figure 5 This is a schematic diagram of an evaporation apparatus. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. The technical solutions of the present invention will be further described below with reference to the accompanying drawings of the embodiments of the present invention. The present invention is not limited to the following specific embodiments.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] In one specific embodiment of this application, a method for preparing a wood-based porous carbon solar evaporator involves crushing and ball-milling waste wood chips into wood powder, mixing them evenly with sodium carboxymethyl cellulose, pressing them into tablets, and obtaining a precursor sample. The precursor sample is then placed in a tube furnace and carbonized under an inert gas atmosphere to obtain the wood-based porous carbon material.

[0029] The wood-based porous carbon material of this application is a promising photothermal material in the field of solar-driven desalination, and therefore the wood-based porous carbon material can also be called a solar evaporator.

[0030] Sodium carboxymethyl cellulose (CMC) functions as both an environmentally friendly binder and a pore-forming agent in the preparation of wood-based porous carbon. Preferably, in the mixture of wood flour and sodium carboxymethyl cellulose, the mass fraction of sodium carboxymethyl cellulose is 20% to 70%, and more specifically, the mass fraction of sodium carboxymethyl cellulose in the mixture is 50%.

[0031] Preferably, the maximum particle size of the wood flour is 200 mesh.

[0032] Preferably, the pressure of the tablet is 3 to 7 MPa.

[0033] Furthermore, the carbonization temperature is 500°C to 700°C, and the carbonization time is 1 to 3 hours.

[0034] In another specific embodiment of this application, a wood-based porous carbon solar evaporator is prepared using the preparation method of the wood-based porous carbon solar evaporator described above.

[0035] In another specific embodiment of this application, the wood-based porous carbon solar evaporator is applied in the field of high-efficiency solar desalination and water purification technology.

[0036] It is worth noting that the process temperature and process time involved in the above embodiments are all temperatures or times used in the experiment. Any reasonable adjustments made by those skilled in the art based on the process temperature and process time provided by the present invention, within the error range, should be included within the protection scope of the present invention.

[0037] The technical solution and effects of the present invention will be further illustrated below through specific embodiments.

[0038] 1. Experimental materials and equipment

[0039] Pure pine sawdust was purchased from Lingshou County Boteng New Materials Co., Ltd.; sodium carboxymethyl cellulose (CMC) and starch were purchased from Tianjin Juhengda Chemical Co., Ltd. (Tianjin, China); sodium chloride (NaCl, >99.5%), magnesium chloride hexahydrate (MgCl2·6H2O, >98.0%), sodium sulfate (Na2SO4, >99.0%), anhydrous calcium chloride (CaCl2, >96.0%), potassium chloride (KCl, >99.5%), sodium bicarbonate (NaHCO3, >99.5%), copper sulfate pentahydrate (CuSO4·5H2O, >99.0%), nickel sulfate hexahydrate (NiSO4·6H2O, >98.5%), ferric chloride (FeCl3, >98.5%), and other chemical reagents were all purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China); methyl orange (MO) and methylene blue (MB) were purchased from Tianjin Zhonglian Chemical Reagent Co., Ltd. All reagents were used directly without purification.

[0040] Equipment: Manual tablet press: MC-15B manual tablet press, MITR Instruments Co., Ltd., Changsha; Tube furnace: OTF-1200X, Hefei Kejing Materials Technology Co., Ltd.

[0041] Characterization Instruments: The thermal stability of the samples was evaluated using a simultaneous thermal analyzer (SDT 650, TA Instruments, USA). Microstructure characteristics were observed using a field emission scanning electron microscope (FE-SEM, SU5000F, HITACHI, Japan). Optical absorption properties were measured using a UV-Vis-NIR spectrophotometer (Lambda 1050, PerkinElmer, USA) in the wavelength range of 250–2500 nm. Sample wettability was characterized by measuring the water contact angle using a contact angle meter (SDC-200S, SINDIN, China).

[0042] 2. Preparation of wood-based porous carbon materials

[0043] First, pine wood was pulverized and ball-milled into wood flour of less than 200 mesh. Then, pine wood chips (sawdust) were mixed with CMC, starch, and polyvinyl alcohol (PVAL) in specific proportions to form a homogeneous mixture. Precursor samples with a diameter of 16 mm and a thickness of 3 mm were prepared under a pressure of 5 MPa. The precursor prepared from 100% pure wood chips was named P-Sd; the precursor prepared from 80 wt% wood chips and 20 wt% starch was named P-SS; the precursor prepared from 60 wt% wood chips and 40 wt% PVAL was named P-SP; the precursor prepared from 80 wt% wood chips and 20 wt% CMC was named P-SC1; the precursor prepared from 50 wt% wood chips and 50 wt% CMC was named P-SC2; and the precursor prepared from 20 wt% wood chips and 80 wt% CMC was named P-SC3.

[0044] Subsequently, the precursor sample was placed in a tube furnace and heated at 150 mL / min under an argon atmosphere. -1 The flow rate was controlled, and carbonization was carried out at 600 °C for 2 hours to obtain the final product.

[0045] Among them, the product after carbonization of precursor P-SC1 has a low degree of porosity and is not suitable for use as an evaporator. The structure of precursor P-SC3 collapses after carbonization and cannot maintain its complete shape, so it is also unsuitable for use as an evaporator. Therefore, evaporators carbonized with precursor P-Sd are labeled as Sd, evaporators carbonized with precursor P-SS are labeled as SS, evaporators carbonized with precursor P-SP are labeled as SP, and evaporators carbonized with precursor P-SC2 are labeled as SC.

[0046] 3. Evaporation Experiment

[0047] A xenon lamp (XENON, XES-50S2, Japan) was used as a solar simulator to provide different light intensities, and its irradiance was measured using a solar power meter (PL-MW2000, Porphyry Technology, China). The mass change of the solution was continuously monitored using an electronic analytical balance to calculate the evaporation rate and photothermal conversion efficiency. Furthermore, an infrared thermal imager (FLIR E6390, Estonia) was used to record infrared images and surface temperatures of the evaporator. Evaporation performance tests were conducted in pure water and NaCl solutions of 3.5 wt%, 10 wt%, 15 wt%, and 20 wt%. In practical application tests, simulated seawater (composed of NaCl, MgCl2, Na2SO4, CaCl2, KCl, and NaHCO3, with concentrations of 24.53, 5.20, 4.09, 1.16, 0.70, and 0.20 g / L, respectively) was used. All experiments were conducted at room temperature (23±1°C) and relative humidity of 45±10%.

[0048] To reduce heat loss, this experiment employed a thermal insulation structure design. Figure 5 (This is a schematic diagram of the evaporation device). The structure uses polystyrene foam, processed into a floating plate that can float on the surface of a 40 mm diameter beaker of water. Its edges fit tightly against the beaker wall to effectively block heat exchange. Pre-drilled channels in the center of the foam contain embedded cotton fibers as the water transport medium. The evaporator is placed above the cotton fibers and covers their surface area. In this structure, the polystyrene foam acts as an insulation layer, effectively isolating the evaporator from the temperature zone of the water below, significantly reducing heat loss due to water conduction. Simultaneously, the cotton fibers continuously supply water to the evaporator through capillary action, ensuring a continuous and stable evaporation process. This design, while suppressing non-evaporative heat dissipation, further improves the overall evaporation efficiency of the system.

[0049] 4. Performance Evaluation

[0050] Evaporation rate and photothermal conversion efficiency are key indicators for evaluating evaporator performance. Evaporation rate (v, kg m³) -2 h -1 The photothermal conversion efficiency is calculated using formula (1). , %) is then determined by formula (2).

[0051]

[0052] Here, The change in mass of the solution is expressed in kg, and A is the effective evaporation area in m². 2 ), Evaporation time (h). (kg m) -2 h -1The net evaporation rate is defined as the difference between the evaporation rate under light conditions and the evaporation rate under darkness. This represents the enthalpy of vaporization of water. Incident solar power density (kW m) -2 ).

[0053] 5. Summary and Discussion

[0054] Figure 1 The cross-sectional morphology of wood chip-based carbon evaporators prepared with different binders is shown. For the Sd evaporator, the cross-section exhibits a typical sheet-like, stacked morphology; the pores are mainly composed of packed voids, and the pore distribution is uneven. Due to the addition of sodium carboxymethyl cellulose (CMC), the cross-section of the SC evaporator changed drastically, showing a rich pore structure. This indicates that CMC not only acts as a binder during pyrolysis, but its gaseous products from thermal degradation may also act as a self-templating pore-forming agent. Furthermore, the organic sodium produced during pyrolysis may catalyze further decomposition of charcoal, promoting the formation of pore structures. The cross-sectional morphology of the SS and SP evaporators is similar to that of Sd, exhibiting an irregular sheet-like stacked structure. This is mainly attributed to the low carbonization yield of starch and polyvinyl alcohol (PVAL).

[0055] like Figure 2 a represents the initial thermogravimetric curve (TGA) of the samples. The TGA curves of all four samples exhibited similar three-stage weight loss characteristics: In the low-temperature stage (<150 °C), each sample experienced only slight weight loss, mainly due to the removal of adsorbed water and a small amount of volatile components. SC and SP showed more significant weight loss in this stage, attributed to the increased bound water content caused by the strong hydrophilicity of sodium carboxymethyl cellulose, and the dehydration effect of polyvinyl alcohol in the initial heating phase, respectively. In the intermediate-temperature stage (250-370 °C), all four samples experienced rapid weight loss, corresponding to the pyrolysis of lignocellulose and organic binders. SS showed the greatest weight loss, due to starch being more prone to pyrolysis and releasing more volatile products. In the high-temperature stage (>370 °C), the weight loss of all four samples slowed down. The residual mass of Sd was higher than that of the sample with added binder, indicating that the binder was more easily decomposed than sawdust.

[0056] Figure 2 b presents the porosity test results for four types of evaporators. The SC evaporator exhibits the highest porosity (62.78%), indicating that the introduction of sodium carboxymethyl cellulose effectively promotes pore formation during carbonization, consistent with the abundant pore structure observed in cross-sectional SEM. Notably, the Sd evaporator has a porosity of 54.5%, slightly higher than the SS and SP evaporators (52.56% and 51.25%, respectively). This may be due to the fact that starch and PVA soften and form a viscous phase during carbonization heating, which fills or blocks the channels formed by sawdust accumulation, thus limiting pore structure development and reducing porosity.

[0057] Figure 2 c shows the thermal conductivity of the evaporators under dry and humid conditions. The results indicate that the thermal conductivity of all evaporators is significantly higher under humid conditions than under dry conditions. This is mainly because under humid conditions, the air in the pores is replaced by water with higher thermal conductivity, forming a more continuous liquid-phase heat transfer channel, thus improving the evaporator's thermal conductivity. Under dry conditions, all four evaporators exhibit good thermal insulation characteristics (<0.2 W / m²). -1 k -1 Of these, SC was the lowest, at only 0.14 W / m. -1 k -1 Under humid conditions, the thermal conductivity of SC is 0.52 W / m. -1 k -1 The thermal conductivity of water at close to 20°C is 0.60 W / m. -1 k -1 ).

[0058] Figure 2 Figure d shows the water contact angle test results of the evaporators. SC has the lowest initial contact angle, only 33°, and achieves complete wetting within 0.5 s, indicating excellent surface hydrophilicity and capillary water absorption capacity. In contrast, the initial contact angles of Sd and SS evaporators are 54° and 45°, respectively, and the water droplets spread on the material surface in similar times (1.1 s and 1.2 s, respectively), exhibiting moderate hydrophilicity. SP has the highest initial contact angle of 68°, with the droplets forming a hemispherical shape on the sample surface. The spreading and penetration process takes 1.8 s to complete, indicating relatively weak surface wettability. Floating test results are shown below. Figure 2 As shown in Figure e, the SC sample can maintain stable buoyancy on the water surface for an extended period. Its excellent buoyancy stability primarily stems from its rich porous structure, which effectively reduces the overall effective density of the material and maintains sufficient buoyancy even after partial water absorption. In contrast, the other three samples have relatively dense structures, leading to continuous water infiltration and retention, causing a gradual increase in effective density and ultimately disrupting the buoyancy balance, resulting in sinking. These self-floating characteristics are crucial for the stable positioning of the interfacial evaporator at the water-air interface, ensuring high evaporation efficiency and long-term stable operation.

[0059] Light absorption characteristics test of four types of evaporators ( Figure 3 a) shows that within the wavelength range of 250-2500 nm, the SC evaporator maintains an absorption rate of over 97% for simulated sunlight, exhibiting excellent and stable broadband light absorption capabilities. Compared to the SC, the other three evaporators have slightly lower light absorption capabilities. It is noteworthy that while the light absorption capabilities of the three evaporators are similar, their absorption in the near-infrared region gradually decreases with increasing wavelength. In periodic illumination tests under dry conditions (… Figure 3(b) The surface temperature of the SC rapidly rises to 90 °C within 10 minutes after the lamp is turned on, then further increases and stabilizes at approximately 100 °C, demonstrating excellent photothermal conversion capability and good thermal stability. After the lamp is turned off, the surface temperature quickly drops back to near its initial value, showing good photothermal response reversibility and cycle stability.

[0060] like Figure 3 As shown in 3c, 3d, and 3e, under one sun's irradiation, the water mass change of each evaporator exhibits an approximately linear decreasing trend over time, indicating that the evaporation process is stable and reliable. Among them, SC shows the highest evaporation rate, reaching 3.41 kg m³. -2 h -1 The efficiency of SC is about 30% higher than that of Sd. At the same time, the evaporation efficiency of SC is as high as 93.5%. Its excellent evaporation performance can be attributed to the synergistic effect of multiple factors, such as the sufficient evaporation interface and smooth water transport channels provided by the porous structure, the continuous water supply due to good hydrophilicity, and the efficient photothermal conversion promoted by high light absorption.

[0061] To evaluate the salt tolerance of the evaporator SC in a high-salt environment, its evaporation performance in solutions with different NaCl concentrations (0-20 wt%) was tested under 1-day conditions. Figure 4 As shown in Figure a, the slope of the NaCl solution mass loss curve decreases slightly with increasing salt concentration, and the corresponding evaporation rate shows a decreasing trend. Figure 4 b), from 3.41 kg m -2 h -1 Reduced to 2.83 kg m -2 h -1 When the NaCl solution concentration is in the range of 10-20 wt%, the evaporation rate remains essentially constant. Meanwhile, changes in salt concentration have little impact on the evaporation efficiency, which remains between 94% and 95%. Figure 4 c). The above results indicate that SC can maintain stable evaporation under high salt conditions and has good salt tolerance. Its salt tolerance was further evaluated by observing the dissolution behavior of 0.2 g NaCl particles on the SC surface. Figure 4 d). NaCl particles were rapidly wetted upon contact with the SC surface and completely dissolved within 100 min. This result indicates that the porous structure of SC enables efficient capillary transport and salt re-dissolution, exhibiting excellent self-desalination capability and effectively inhibiting salt crystallization and accumulation at the evaporation interface. Furthermore, to evaluate long-term salt tolerance, a 12-h continuous evaporation test was conducted (…). Figure 4 e). Under 20 wt% NaCl solution conditions, the evaporation rate decreased in the first 4 hours, then gradually stabilized, and after 12 hours of operation, the evaporation rate remained at 1.8 kg m³. -2 h-1 .

[0062] To evaluate the application potential of the evaporator SC in practical water treatment scenarios, its evaporation performance and purification effect were tested in simulated seawater and dye wastewater systems. Figure 4 As shown in f, SC reaches 3.31 kg m under simulated seawater conditions. -2 h -1 It exhibits a high evaporation rate and efficiency of 94.1%. Its evaporation efficiency is slightly higher than that of methyl orange (MO) and methylene blue (MB), while its evaporation rate remains essentially the same. Analysis of the main ion concentrations before and after simulated seawater evaporation shows that ( Figure 4 g), Na + K + Ca 2+ and Mg 2+ The concentrations were initially 9810 mg / L. -1 520 mg L -1 440 mg L -1 1210 mg L -1 The concentration was reduced to 1.58 mg / L. -1 0.44 mg L -1 0.9 mg L -1 0.14 mg L -1 Meanwhile, the treated water quality has met the drinking water standards set by the World Health Organization (WHO), indicating its outstanding application potential in seawater desalination. After SC treatment, the characteristic absorption peaks of MO and MB dyes in the UV-Vis spectrum almost completely disappeared. Figure 4 (h and 4i) both showed removal rates close to 99%; the illustrations compared the appearance of the initial dye wastewater and the evaporation collection liquid, showing a significant improvement in the quality of the fuel wastewater. In summary, the SC evaporator combines stable interfacial evaporation performance with excellent desalination / organic contaminant removal capabilities, making it suitable for various water treatment scenarios such as seawater desalination and organic dye wastewater purification.

[0063] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a wood-based porous carbon solar evaporator, characterized in that, Includes the following steps: Waste wood chips were crushed and ball-milled into wood powder, then mixed evenly with sodium carboxymethyl cellulose, and compressed into tablets to obtain the precursor sample. The precursor sample was placed in a tube furnace and carbonized in an inert gas atmosphere to obtain the waste wood chip-derived carbon material.

2. The method for preparing the wood-based porous carbon solar evaporator as described in claim 1, characterized in that, In the mixture of wood flour and sodium carboxymethyl cellulose, the mass fraction of sodium carboxymethyl cellulose is 20% to 70%.

3. The method for preparing the wood-based porous carbon solar evaporator as described in claim 1, characterized in that, In the mixture of wood flour and sodium carboxymethyl cellulose, the mass fraction of sodium carboxymethyl cellulose is 50%.

4. The method for preparing the wood-based porous carbon solar evaporator as described in claim 1, characterized in that, The maximum particle size of the wood flour is 200 mesh.

5. The method for preparing the wood-based porous carbon solar evaporator as described in claim 1, characterized in that, The pressure of the tablet is 3 to 7 MPa.

6. The method for preparing the wood-based porous carbon solar evaporator as described in claim 1, characterized in that, The carbonization temperature is between 500°C and 700°C.

7. The method for preparing a wood-based porous carbon solar evaporator as described in claim 1, characterized in that, The carbonization time is 1 to 3 hours.

8. A wood-based porous carbon solar evaporator, characterized in that, It is prepared by the method of any one of claims 1 to 7 for the preparation of a wood-based porous carbon solar evaporator.

9. The application of the wood-based porous carbon solar evaporator as described in claim 8 in the field of high-efficiency solar desalination and water purification technology.

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