Compositional and Structural Reconstitution of Woody Biomass Framework via Dual-Functional Lignin Engineering Toward Efficient and Salt-Resistant Solar Desalination

Compositional and Structural Reconstitution of Woody Biomass Framework via Dual-Functional Lignin Engineering Toward Efficient and Salt-Resistant Solar Desalination | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Compositional and Structural Reconstitution of Woody Biomass Framework via Dual-Functional Lignin Engineering Toward Efficient and Salt-Resistant Solar Desalination Chaoji Chen, Bin Wang, Yanrong He, Zhihao Yang, Qian Sun, Xipeng Zhang, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7392399/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Mar, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Solar-driven interfacial evaporation is a promising solution to address global freshwater scarcity, with woody biomass-based evaporators standing out for their sustainability and cost-effectiveness. However, current woody biomass-based systems often suffer from inefficient water management and suboptimal photothermal performance. Herein, we develop a dual-function lignin-engineered reconstituted wood framework strategy, achieving both compositional and structural optimization of woody biomass to enhance its evaporation performance via superior water management and thermal management. By partially retaining and reconfiguring lignin within the woody biomass framework, a higher fraction of loosely bound “intermediate water” with reduced evaporation enthalpy is generated while preserving the water-pumping capability. Concurrently, the extracted lignin is upcycled via laser-induced graphitization into a broadband photothermal layer composed of hierarchical graphene/graphitic carbon structures with solar absorptivity exceeding 95%. This synergistic design results in the E-150 solar evaporator, which achieves an evaporation rate of 2.24 kg m⁻² h⁻¹ and a photothermal conversion efficiency of 91.52% under one-sun irradiation, surpassing most reported wood-based evaporators. Moreover, the retained lignin sustains multiscale channel integrity, imparting strong salt resistance, high recyclability, and robust purification capabilities. This integrated biomass valorization strategy provides a scalable, low-cost, and eco-friendly route for high-performance solar desalination and sustainable water-energy applications. Physical sciences/Chemistry/Green chemistry/Sustainability Physical sciences/Energy science and technology/Renewable energy/Solar energy/Solar thermal energy Scientific community and society/Water resources Woody biomass Lignin Lignocellulose Solar desalination Salt resistance Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction The escalating global water crisis – driven by population growth, industrialization and climate change – has rendered freshwater increasingly scarce. 1 Seawater, which makes up nearly 97.5% of the Earth's water resources, is a viable source, particularly for coastal regions facing severe freshwater shortages, but conventional desalination methods (reverse osmosis or multistage flash) are energy-intensive and costly 2,3 . In contrast, interfacial solar evaporation offers a promising alternative: it harnesses highly renewable solar energy to heat only a thin surface layer of water, minimizing thermal losses and operational complexity 4 . This approach can transform seawater and wastewater into drinkable water in a low-cost, eco-friendly manner, which is critical for coastal and arid regions facing chronic freshwater shortages. Interfacial solar evaporation typically consists of a photothermal top layer that absorbs sunlight and an underlying wick or porous matrix that transports water upward 5 , 6 . Wood, being an abundant and renewable natural product, possesses a layered porous structure with low-curvature channels capable of floating on water 7,8 . Combined with anisotropic thermal conduction across cross-section and longitudinal sections, wood holds significant potential for application in interfacial solar evaporation 9 . State-of-the-art materials have pushed photothermal conversion toward the thermodynamic limit, so further gains depend on improved water management 10 . In particular, recent work (inspired by hydrogel evaporators) has shown that creating a higher fraction of loosely bound intermediate water via structural or chemical tuning, which can dramatically lower the evaporation enthalpy and boost evaporation rates 11,12 . However, native wood contains hydrophobic lignin that tightly binds cellulose fibers together, which tends to impede the pumping of water to the evaporation interface. Many reported wood evaporators therefore chemically remove lignin from wood to open its pores and increase wettability 13,14 . However, complete removal of lignin has drawbacks: it entirely consumes the lignin resource and, importantly, eliminates the only intrinsic hydrophobic component of wood. As a result, excessive hydrophilicity leads to domination by high-enthalpy water (combined water and free water), and limits the ultimate evaporation rate 15 . Recent molecular simulations and experiments confirm that introducing an appropriate amount of hydrophobic components can help create more intermediate water with low evaporation enthalpy by weakening the hydrogen bond network between the matrix and water 16 . Therefore, as the only hydrophobic component and binder in wood, the controlled presence of lignin can actually be leveraged to water states inside wood from both spatial and chemical composition perspectives. Adjusting the lignin content in wood to maintain effective water pumping capacity while increasing the intermediate moisture content paves the way for high-performance woody biomass-based solar evaporators with superior economic and environmental benefits, making them more suitable for large-scale application than hydrogel solar evaporators. Another challenge in woody biomass-based evaporators is achieving efficient photothermal conversion while maintaining sustainability. Natural wood is weakly absorptive of sunlight, so most designs deposit external coatings (e.g. plasma metal nanoparticles or semiconductor inks) to boost absorption 17,18 . These additives can add cost and environmental risk, conflicting with the goal of green desalination. Carbon-based nanomaterials, especially graphene, have been widely used in the photothermal conversion system of woody biomass-based solar evaporators due to their excellent broad-spectrum absorption, outstanding photothermal conversion efficiency, strong stability and high abundance 19,20 . Notably, lignin, with its unique aromatic ring structure and high carbon content 21 , can promote the formation of sp 2 hybrid ordered structure of graphene crystals, making it an ideal raw material for preparing graphene 22,23 . However, cumbersome processes and harsh preparation conditions limit the large-scale development of lignin-based graphene. Laser etching technology, with the advantages of simple operation, low cost, high precision, energy saving and environmental protection 24 , can ignore the the severe heterogeneity of lignin, promoting the sustainable development of lignin-based photothermal conversion materials 25 . In this work, we developed a lignin-engineered reconstituted woody framework strategy that simultaneously addresses two key challenges in solar evaporation based on sustainability and economy: the efficient preparation of high-performance photothermal layers and the reduction of water evaporation enthalpy ( Fig. 1 ). Theoretical simulations and experimental results reveal that appropriate lignin removal modulates both the spatial microstructure and the distribution of functional groups, promoting the formation of intermediate water with weaker hydrogen bonding. This lowers the evaporation enthalpy while preserving effective water transport to the evaporation interface. Simultaneously, the removed lignin is not wasted, which is recovered and processed via laser etching into a composite carbon layer composed of graphite carbon and graphene. This carbon layer exhibits a hierarchically ordered porous architecture (micronscale macropores enhance the capture of incident light, while mesopores and micropores efficiently absorb scattered and reflected light), resulting in solar absorptivity exceeding 95%. Moreover, the high specific surface area of the porous carbon layer, combined with the presence of graphene domains, increases the density of photothermal conversion sites and further enhances overall conversion efficiency. As a result, the resulting evaporator E-150 demonstrated an evaporation rate of up to 2.24 kg m -2 h -1 and a photothermal conversion efficiency of 91.52% with minimal processing. This lignin-engineered reconstitution wood not only outperforms most reported woody biomass-based solar evaporators in terms of evaporator performance but also has outstanding environmental and economic benefits, which holds great promise for promoting the large-scale application of woody biomass-based solar evaporators. Water states within the lignin-engineered reconstituted wood As shown in Fig. S1 and Table S1 , the lignin content decreased from 25.77% in natural wood (labelled as Wood) to 16.70% in W-150 obtained after pretreatment with an alcohol solution system at 150 o C. In contrast, the lignin in W-A, obtained by sodium chlorite delignification, was almost completely removed. The hydrophilicity of the woody biomass framework significantly affects water pumping capacity and water states 26 . The hydrophilicity of W-150 improved due to partial removal of the hydrophobic lignin, while W-A, lacking lignin, exhibited superior hydrophilicity ( Fig. S2 ). The increase in the hydrophilicity of the woody biomass framework facilitates the water pumping to the evaporation interface. However, previous reports have shown that excessive hydrophilicity will lead to the dominance of free water, which has a high evaporation enthalpy (about 86 times the enthalpy of intermediate water), thereby limiting the further evaporation rate 27,28,29 . The influence of lignin on the water states within the woody biomass framework stems from two perspectives ( Fig. 2a ). Firstly, lignin, as a main component of lignocellulose, is entangled with cellulose and hemicellulose via complex lignin–carbohydrate complex (LCC) bonds 30,31 . Therefore, lignin content closely affects the crosslinking degree of the woody biomass framework. Based on these chemical composition analysis results, final-state models of each simulation system were constructed using Visual Molecular Dynamics (VMD). Compared to the Wood ( Fig. S3 ) and the W-A ( Fig. 2b ), the W-150 system ( Fig. 2c ) is more homogeneous and compact (as evidenced by its smaller cyclotron radius, Fig. S4 ). This suggests that the W-150 system has less void space that is prone to generating free water, thereby providing spatial conditions favorable for the generation of more intermediate water. On the other hand, lignin contains both hydrophilic functional groups (such as hydroxyl and carboxyl groups), as well as hydrophobic phenyl ring structures (the only hydrophobic component in lignocellulose). That affects the formation of hydrogen bonds between the woody biomass framework and water molecules in a moist state, thus impacting the number and strength of those hydrogen bonds. Crucially, pretreatment selectively enriched syringyl (S) units in lignin of W-150 (L-W150), elevating the S/G ratio from 2.31 in lignin of Wood (L-Wood) to 5.05 in L-W150 ( Figs. 2d and S5 ). The aromatic ring of S-units bears two methoxy groups and one phenolic hydroxyl group, providing increased density of hydrogen-bond acceptors and donors. While their polar functional groups facilitate water adsorption, the inherent hydrophobicity of the aromatic ring prevents excessive hydrophilicity that would generate tightly bound water 32 . Furthermore, the symmetric distribution of methoxy groups in S-units creates a uniform polar microenvironment. This configuration stabilizes intermediate water layers through a multi-site network of weak-to-moderate hydrogen bonds that entrap water molecules 33 . Consequently, the enhanced S/G ratio in L-W150 is anticipated to promote greater generation of intermediate water. To this end, molecular dynamics simulations were conducted to model the interactions between the lignocellulosic molecular chains and water (the Wood sample was excluded from further analysis due to its poor water-pumping capability). The results ( Fig. S6 ) show that, compared with W-A, W-150 has a higher proportion of intermediate water ( Fig. 2e ) and a shorter lifetimes of water hydrogen bonds ( Fig. 2f ). This indicates that appropriately retained lignin can facilitate the formation of intermediate water via weak hydrogen bonding and reduce the difficulty of evaporating water clusters ( Fig. S8 ), thereby lowering the enthalpy of water evaporation. To validate these theoretical calculation findings, differential scanning calorimetry (DSC), dark evaporation experiments, Raman and low field nuclear magnetic resonance (LF-NMR) were systematically employed to investigate the effect of lignin on the water states and the evaporation enthalpy of water in woody biomass frameworks. As shown in Fig. S9a , the DSC curve of pure water showed a sharp peak. The water peak in W-A flattened out, but still had sharp peaks, indicating too much free water. In W-150, the water appeared broader and lacked sharp peaks. The evaporation enthalpies of water in pure W-A and W-150 calculated from the DSC curve were 1990 and 1670 J/g, respectively ( Fig. S9b ). In the dark evaporation experiment, as shown in Fig. 2g , the evaporation enthalpies of water in W-A and W-150 were 1842 and 1397 J/g, respectively. The results of both methods showed that proper lignin content was beneficial in reducing the evaporation enthalpy of water. However, it was found that the evaporation enthalpy obtained by the DSC curve was higher than that obtained by the dark evaporation experiment, because the DSC method also involves the evaporation of bound water besides intermediate water and free water. To further explore the effect of lignin content on the evaporation enthalpy of water in the wood, woody biomass frameworks with different lignin content were obtained under the pretreatment condition of 140-170 o C. The evaporation enthalpy of water in the woody biomass framework obtained by DSC increased with the decrease in lignin content, and W-140 had the lowest evaporation enthalpy ( Fig. S9b ). However, the evaporation enthalpy of water obtained by the dark evaporation experiment decreased first and then increased with the decrease of lignin content, and W-150 had the lowest evaporation enthalpy ( Fig. S9c ). The difference between the two results stemmed from the fact that W-150, with lower lignin content, had better hydrophilicity and more bound water than W-140, resulting in a higher evaporation enthalpy obtained by DSC. It is worth noting that the actual use of solar evaporators almost does not involve the evaporation of bound water, which is closer to the dark evaporation experiment 34 . Therefore, the results of the dark evaporation experiment were used as the basis for the subsequent discussion. LF-NMR were used to investigate spin proton relaxation, providing information on the nuclear mobility of bound and free water 20 . The transversal relaxation properties of water in the woody biomass framework were investigated by 1D LF-NMR, which attempted to explain the influence mechanism of lignin content on water states in wood. Generally, the water that is more tightly bound to the wood (such as bound water) has a shorter transverse relaxation time (T 2 ); conversely, the free water has a longer T 2 20 . As shown in Fig. S10a , the T 2 distribution curve of Wood showed four peaks, indicating the presence of four water states. Relaxation peaks of T 2 less than 1 ms (T 21 ) and around 1000 ms (T 24 ) are attributed to bound and free water, respectively 35,36 . Large amounts of capillary water were present in extremely fine channels in the wood, which appeared at the T 23 relaxation peak near 45 ms, 37 while acromion (T 23 ) might be intermediate water in the large diameter channels. It was found that the content of bound and free water in W-A increased, but the T 22 peak belonging to intermediate water disappeared ( Fig. 2h ), indicating that the absence of lignin was not conducive to the formation of intermediate water. As for W-150, the T 22 and T 23 peaks were combined, showing that the properties of capillary water at this time were very similar to those of intermediate water. However, capillary water is difficult to distinguish between bound water and intermediate water through 1D LF-NMR. To further subdivide capillary water, 2D LF-NMR was used to characterize the water states in the woody biomass framework, which effectively reduces the interference caused by water overlap and chemical composition. The longitudinal relaxation time (T 1 ) can reflect the time for the nuclei of high-energy states to return to the ground state through energy exchange with the surrounding environment during relaxation, while T 2 corresponds to the time it takes for a high-energy nucleus to transfer energy to a similar low-energy nucleus and return to the ground state 38 . The T 1 /T 2 value indicates the mobility of hydrogen atoms, and a lower value means that the water molecule is more mobile. As shown in Fig. S10b , four main peaks could be observed in the 2D LF-NMR spectrum of Wood, among which the D peak with the largest T 1 /T 2 value is usually identified as the signal of polymers or bound water in wood, while the A peak with the smallest T 1 /T 2 value represents free water. Peaks B and C originated from capillary water, which corresponded to the water in the amorphous region of microfibrils and its surrounding hemicellulose, as well as the water in the amorphous region of the hemicellulose and lignin, respectively 39 . Since lignin and hemicellulose were almost completely removed, no peak C appeared in the 2D LF-NMR spectrum of W-A, and a strong peak A was observed ( Fig. 2i ). The stronger peak A and the weaker peak B indicated that capillary water in W-A had similar properties to free water. Notably, a strong peak B was observed in the 2D LF-NMR spectrum of W-150, which were further divided into peaks B 1 and B 2 to distinguish better the capillary water states ( Fig. 2j ). The peak B 2 with a smaller T 1 /T 2 value had better water mobility, indicating that water molecules were clustered under the action of hydrogen bonds, which was not conducive to water evaporation. The water in peak B1 was judged as intermediate water. Compared with W-A and Wood, the B 1 signal in W-150 was significantly enhanced, which meant that W-150 had more intermediate water. Moreover, to be closer to the actual use scenario, 2D LF-NMR tests were performed on W-A and Wood in a water-filled state. As shown in Fig. S11 , only one strong peak was shown in both spectra. By comparison, W-150 had a larger T 1 /T 2 value than W-A, which once again verified that W-150 had a larger intermediate water content. To prove the existence of different water forms, Raman spectroscopy of various woody biomass frameworks was fitted into four peaks by the Gaussian function, as shown in Fig. S12 . The results showed that W-150 presented the largest ratio of intermediate water to free water due to the proper delignification, consistent with the analysis of evaporation enthalpy and LF-NMR. Moreover, note that since a certain amount of lignin was still retained as a support, the multistage channels in W-150 were intact, especially the ray cells ( Fig. S13 ), which will facilitate the transverse shuttle of salt ions, protecting the salt resistance 40 . In summary, the hydrophilicity, functional group composition and crosslinking degree of the woody biomass framework were affected by lignin content. Appropriate lignin retention encouraged the production of more intermediate water in the woody biomass framework (especially in the capillary region), which could effectively pump water to the evaporation interface while reducing the evaporation enthalpy, thereby increasing the evaporation rate ( Fig. 2c ). In addition, due to the partial retention of lignin, the multistage channel structure was preserved intact, which was conducive to salt resistance. Laser-etched surfaces The lignin recovered during the ethanol solution pretreatment was coated on the surface of W-150, which was then laser etched to prepare the photothermal conversion layer of the evaporator ( Fig. 3a ). After laser etching, the surface of the evaporator shows increased hydrophilicity ( Figs. 3b and S14 ) and an orderly porous structure ( Fig. 3c ). As shown in Fig. 3e , compared with other carbonization technologies, the graphitized layer obtained by laser etching technology showed a satisfying surface morphology (rich, multi-layered and ordered hierarchical pores) and a specific surface area of up to 100.77 m 2 g -1 ( Fig. S15 ). The micronscale macropores facilitate effective capture of incident sunlight, while the mesopores and micropores efficiently absorb scattered and reflected light. This hierarchically ordered porous architecture induces a pronounced blackbody effect, significantly enhancing broadband solar absorption and localized photothermal conversion. Moreover, the high specific surface area of the porous carbon layer promotes the formation of nan/microscale water droplets with a lower evaporation enthalpy on the surface, which will be proved in subsequent experiments.. Furthermore, regardless of the coating process or the laser etching process, the multistage channels and transversely shuttling ray cells in the woody biomass framework were retained ( Fig. S16 ), which would guarantee the anti-salt crystallization performance of E-150. Furthermore, the laser etching depth of close to 60 μm ( Fig. 3d ) and the laser-induced graphene (LIG) observed inside the large channels within the woody biomass framework ( Fig. S17 ) would further promote sunlight absorption. In addition to the orderly porous structure, the LIG had a crystal region with a lattice spacing of 0.349 nm ( Fig. 3e ), which could be attributed to the spacing of the two adjacent (002) planes in graphitic carbon 41 . Moreover, as shown in Fig. 3f, three main peaks could be observed in the Raman spectrum of the E-150 surface. Among them, the D-peak (1340 cm -1 ) and G-peak (1570 cm -1 ) are attributed to lattice defects (sp 3 hybridization) of carbon atoms and in-plane stretching vibrations of sp 2 hybridization of carbon atoms, respectively 42 . The peak (2670 cm -1 ) comes from second-order band-boundary phonons, which are usually related to the number of graphene layers 43 . The distinct peak and small I D /I G value (0.69) indicated the presence of graphene with fewer stacked layers. However, there was still some sp 3 hybridization at the edges of the surface carbon layer. The results of the TEM and Raman analyses showed that both graphene and graphitic carbon were present in the surface carbon layer. Graphene can effectively absorb sunlight from the ultraviolet to infrared range and has excellent photothermal conversion efficiency and thermal conductivity 44 . However, the complex preparation process and the exorbitant price of graphene make it impractical to use the photothermal conversion layer composed only of graphene. Moreover, graphene usually requires support material to enhance its structural stability and mechanical strength, but the interface compatibility with the support material still faces difficulties 45 . In LIG, porous graphitic carbon served as a support material for graphene, which not only provided a high specific surface area to promote the absorption of sunlight, but also complements the disadvantages of graphene without having to consider interface compatibility issues to overcome the defects of limited light absorption efficiency and single light absorption direction of few-layer graphene monomers. Observing the changes of elements after laser etching showed that carbon elements increased and oxygen elements decreased significantly ( Fig. S18 ). Combined with the previous reports, the graphitization mechanism could be inferred as follows: due to the violent vibration within lignin molecules caused by laser radiation, the local temperature rapidly increased, resulting in C-O bond and C=O bond breaking and gas release ( Fig. 3a ) 46 . At the same time, a part of the region underwent a transition from sp 3 hybridization state to sp 2 hybridization state, and the benzene ring structure of lignin was organized into a graphene structure. It was worth noting that untreated balsa wood had little carbonization effect on the surface of the wood substrate at the same laser power due to its low lignin content and the presence of LCC bonds ( Fig. S19 ). The ability of the evaporator's photothermal conversion layer to absorb sunlight was enhanced ( Fig. S20 ). As shown in Fig. S21 , compared with W-150, the light absorption capacity of C-150 in the short-wavelength band was increased due to the introduction of lignin, but there was almost no change in the long-wavelength band. Under the synergistic action of graphene and graphitic carbon, the light absorption capacity of E-150 in the full band of 300-2500 nm had been significantly improved, exhibiting an absorption rate of up to 95.48% for sunlight, which was much higher than that of the W-150 and C-150 ( Fig. 3g ). The LIG (a composite material composed of graphene and porous graphitic carbon) obtained by laser etching of lignin showed outstanding sunlight absorption capacity and potentially excellent photothermal conversion efficiency. Furthermore, A simple process of this work is advantageous for the large-scale preparation of a reconstituted wood solar evaporator. According to the experimental conditions of this work, we further scaled up the production, achieving a large-sized evaporator of 0.88 m² or an evaporator of arbitrary shape to meet the requirements of complex practical conditions ( Figs. 3h and S22 ). Evaporation properties Based on the above analysis, partial delignification significantly enhanced the intermediate water content. Moreover, LIG derived from recovered lignin on the surface of the evaporator demonstrated superior solar absorption and photothermal conversion efficiency. These characteristics established a solid foundation for the development of high-performance woody biomass-based solar evaporators. As shown in Fig. 4a , woody biomass-based solar evaporators E-W, E-A and E-150 were prepared based on Wood, E-A and E-150, respectively, and evaporation rates were 1.51, 1.72 and 2.24 kg m -2 h -1 under one sunlight, respectively. Since the manufacturing process of the photothermal conversion layer was the same, the difference in evaporation rates was mainly due to the woody biomass framework. According to the analysis results in Section 2.1, the woody biomass framework of E-W contained a large amount of lignin, resulting in its insufficient ability to pump water to the evaporation interface, while the water within E-A was dominated by free water with high enthalpy of evaporation due to its excellent hydrophilicity. In the case of E-150, appropriate delignification increased the intermediate water content in the woody biomass framework while efficiently pumping water to the evaporation interface. Moreover, the photothermal conversion layer composed of graphite carbon and graphene not only had superior light absorption capacity and photothermal conversion efficiency, but also promoted the formation of microdroplets with low evaporation enthalpy in the pumped water ( Fig. S23 ), thus improving the evaporation performance. In addition, the comparison of woody biomass-based solar evaporators with different lignin content showed that the evaporation rate first increased and then decreased with the decrease of lignin content, and E-150 showed the highest evaporation rate ( Fig. 4b ), which corresponded to the analysis results of intermediate water content. Based on W-150, the influence of laser power on the evaporation performance was also discussed. As shown in Figs. 4c and S24 , when the laser power was less than 45%, lignin could not be effectively graphitized, resulting in inferior light absorption performance and photothermal conversion efficiency of the evaporator surface. However, when the laser power was excessive (50%), Raman spectra showed a large I D /I G value and almost no 2D peaks could be observed ( Fig. S25 ). At this time, the surface of the evaporator was over-graphitized, mainly composed of graphite carbon, and almost no graphene structure. Therefore, achieving a composite carbon layer with the complementary advantages of graphite carbon and graphene was impossible, reducing light absorption and photothermal conversion capacity. Furthermore, the photothermal conversion capability of the evaporator was investigated by measuring the temperature change of the surface. Fig. 4g showed that the temperature of the evaporator surface rapidly rose to 39.1 o C in 1 min under one solar irradiation, indicating the superior photothermal conversion capability of the E-150. After 30 min of irradiation, the temperature of the evaporator surface was stable at about 50 o C, and the water temperature was 31 o C, indicating a thermal localization effect, mainly due to the low thermal conductivity caused by the porous structure of the wood. The thermal localization effect could reduce the heat loss during evaporation and improve the evaporation performance. 47,48 Due to excellent water and thermal management, the E-150 exhibited an evaporation rate of up to 2.24 kg m -2 h -1 and a photothermal conversion efficiency of 91.52% under one solar irradiation ( Fig. 4d ), surpassing most reported woody biomass-based solar evaporators ( Fig. 4e and Table S3 ). Although a few reported woody biomass-based solar evaporators have evaporation performance close to or better than the E-150, these preparation processes are complex and require the introduction of metals or metal oxides, which further increases their cost and potential environmental hazards. Furthermore, the introduction of new carbon dots can endow the evaporator with evaporation performance comparable to that of E-150, but the preparation of these carbon dots requires a large amount of reagents and a long processing time (over 20 hours), resulting in a low efficiency of evaporator preparation. Moreover, the introduction of new carbon dots can endow the evaporator with evaporation performance comparable to that of E-150, but the preparation process for these carbon dots requires a large amount of reagents and an extended period (over 20 h), leading to low efficiency in evaporator preparation. Different from these advanced woody biomass-based solar evaporators mentioned above, this work uses fully biomass-based materials, with a low energy consumption, short processing time, and no additional metal materials to prepare highly efficient woody biomass-based solar evaporators. This lignin-engineered reconstituted woody framework strategy offered simplicity in operation, high resource utilization, low energy consumption, and less pollution. Compared to reported woody biomass-based solar evaporators similar or better evaporation performance, it demonstrated superior environmental and economic benefits ( Fig. 4f ). This highlights its exceptional potential for commercial application, underscoring its promising scalability and market viability in sustainable technology solutions. Seawater desalination and wastewater purification Salt ions in seawater/sewage will concentrate, crystallize and accumulate during evaporation, resulting in salt pollution 49 . As shown in Fig. 5a , the evaporation rate of E-150 in simulated brine with 3.5% and 5.0% salinity stabilized at about 2.15 kg m -2 h -1 within 6 h under one solar irradiation, which was almost the same as that in pure water. In addition, when the brine salinity was increased to 10%, the evaporation rate was reduced to 1.96 kg m -2 h -1 , but the performance remained stable during the long evaporation process ( Fig. S26 ). However, when the salinity exceeded 20%, salt crystallization occurred at the evaporation interface of E-150, causing the evaporation rate to continue decreasing. These results showed that E-150 had an acceptable resistance to salt crystallization, which was suitable for all seawaters in the world, and some high-salinity brines from industry (≤10%). The salt resistance of E-150 was mainly due to the partial retention of lignin in the woody biomass framework, which made the interconnected multistage channel structure intact. As shown in Fig. 5b , these multistage channels provided low-tortuosity pathways with different hydraulic conductivities. When the desalination was carried out, the water flux in the small-diameter channel was smaller than that in the large-diameter channel, resulting in a larger salt concentration in the small-diameter channel. The resulting in-plane concentration gradient encouraged salt ions to shuttle transversally through the ray cell. Simultaneously, salt ions accumulated inside the large-diameter channels diffused back into the seawater. This multidirectional mass transfer characteristic not only endowed E-150 with anti-salt crystallization properties, but also enabled the salt crystals on the evaporator surface to be efficiently eliminated under dark conditions ( Fig. S27 ). The efficient elimination of salt crystals under dark conditions could further broaden the practical application scenarios of E-150 through the day-night cycle. To verify the application of E-150 under the actual sun ( Fig. 5c ), an outdoor evaporation test was conducted in actual seawater from the Bohai Sea (approximately 40° N and 121° E) on September 20, 2024 in Beijing, China (8:00-17:00). During the evaporation test, the water vapor is condensed in the cooling area to avoid the effect of light occlusion and light refraction by the condensation water at the top ( Fig. S28 ). As shown in Fig. 5d , the evaporation rate of E-150 gradually increased in the initial stage, and stabilized at about 2.00 kg m -2 h -1 from 11:00 to 14:00, demonstrating the practical application potential of E-150. It is worth noting that the lower evaporation rate in practical applications is due to the weaker solar flux in Beijing during autumn. The long-term stability and cycling performance of E-150 were investigated using actual seawater. As shown in Fig. 5e , E-150 was continuously evaporated in seawater for 12 h under one solar irradiation, showing a stable evaporation rate of 2.16 kg m -2 h -1 , and almost no salt crystallization was observed. Moreover, during 10 consecutive 4 h evaporation tests, the evaporation rate of E-150 still remained stable ( Fig. 5g ), demonstrating excellent long-term stability. Furthermore, the E-A and E-150 used in seawater were air-dried at room temperature, and their recyclability was compared. As shown in Figs. 5f and S29 , there was almost no change in E-150 after recovery, while the volume of E-A was sharply reduced after recovery, and the surface carbon layer was seriously damaged. The excellent recyclability of E-150 was attributed to the rigidity provided by the partially retained lignin ( Fig. S30 ). In contrast, E-A lacking lignin not only could not be recycled, but also was prone to surface collapse during the process of lignin solution coating ( Fig. S31 ). Furthermore, due to the higher proportion of intermediate water with weak hydrogen-bonding characteristics in E-150, the binding energy between this water and contaminant particles is smaller. Thus, E-150 exhibits enhanced purification capacity ( Fig. S32 ). Conclusion This work demonstrates a compositional and structural reconstitution strategy of a woody biomass framework that enables simultaneous optimization of water transport and photothermal conversion in solar evaporators. Combining theoretical simulations with experimental validation, this study reveals that partially retained lignin facilitates the formation of intermediate water through both functional group interactions and microscopic spatial conditions, thereby reducing the evaporation enthalpy while ensuring effective water pumping to the evaporation interface. Simultaneously, the photothermal conversion layer prepared by laser etching of lignin combined the advantages of graphene and graphite carbon while exhibiting an ordered multistage pore structure, which had excellent light absorption capacity, photothermal conversion efficiency and promoted the formation of microdroplets with low enthalpy of evaporation. Under one-sun illumination, the evaporator E-150 achieves a high evaporation rate of 2.24 kg m⁻² h⁻¹ and a photothermal conversion efficiency of 91.52%, outperforming most previously reported woody biomass-based solar evaporators. Additionally, the appropriate lignin content in the woody biomass framework provided a solid guarantee for the evaporator's anti-salt crystallization performance, recovery, and purification performance. The reconstituted woody framework strategy proposed in this work offers a simple, low-energy, and cost-effective method with substantial potential for large-scale application, providing a promising model for the sustainable development of woody biomass-based solar evaporators, balancing both economic and environmental benefits. Experimental Section Materials: The chemical composition of balsa wood from Fujian Province, China, is shown in Table S1, and the size of the sample used in this study was 10*10*5 mm. Aluminum chloride hexahydrate (97.0%), sodium hypochlorite pentahydrate (≥39%), sodium alginate (AR), sodium hydroxide (96%), ethanol (99.7%), methylene blue (≥70.0%), and direct red 80 (≥25%) were purchased from Aladdin Co., Ltd. Other reagents were analytical grade and purchased from Macklin Co., Ltd. The actual seawater was taken from China's Bohai Sea (approximately 40° N and 121° E) in October 2023, which was not further treated before use. Pretreatment in alcohol solution system: Before pretreatment, the balsa wood blocks were immersed in a reaction mixture, ethanol-water solution (1:1), with 0.02 mol/L aluminum chloride for 2 days. The soaked balsa wood blocks and the reaction mixture were added into a polytetrafluoroethylene-lined reactor for delignification pretreatment for 3 h, and the effect of pretreatment temperature (140-170 °C) was studied in detail. After the pretreatment, the wood blocks were taken out and immersed in a 50% ethanol aqueous solution to replace the solution containing lignin, and this step was repeated twice. Finally, the wood blocks were immersed in deionized water to displace the ethanol and freeze-dried to obtain a woody biomass framework (W-140 to W-170). For the pretreatment liquid, ethanol was recovered by vacuum rotary evaporation, and lignin was obtained by centrifuging for subsequent laser etching. It was worth noting that all chemicals used in this section were easily recyclable. In addition, as a control sample, wood was completely lignin-removed by the traditional sodium chlorite process to obtain woody biomass framework W-A, and the lignin in this process could not be recovered. Specific operations were described in the Supporting Information. Laser etching: To better contrast, the lignin used for laser etching was the lignin recovered from the above pretreatment temperature of 160 o C. 0.5 g lignin and 0.2 g sodium alginate were dissolved in 10 mL of 0.1 M sodium hydroxide solution, then 0.3 mL solution was evenly coated on the surface of a woody biomass framework and air-dried. Subsequently, 0.3 mL of the solution was evenly coated on the surface of the woody biomass framework and air-dried. Finally, a series of woody biomass-based solar evaporators were obtained by laser etching using a semiconductor laser engraving machine with a peak laser power of 7.0 W. Except for the samples that investigated the effect of laser power, the laser power used in the etching process of the other samples was 45%, and the scanning rate was 70 mm/s. Material Characterization: After the woody biomass framework was crushed, its chemical composition was determined using the previously reported method. 50 The morphologies and energy-dispersed X-ray spectroscopy (EDS) were observed by scanning electron microscope (SEM, Hitachi Regulus8100, Japan) and high-resolution transmission electron microscopy (HRTEM, JEM-2100, Japan). Raman spectra of graphitization layers and water in woody biomass frameworks were detected by Raman microscopy (X-plor, France). Surface wettability was determined by an OCA20 Contact angle measurement system (Data-physics, Germany). The light absorption capacity of the evaporator was recorded by UV–visible-NIR spectrophotometer (UV3600, Shimadzu, Japan). The evaporation enthalpies of water in the woody biomass framework were determined by a differential scanning calorimeter (DSC-60 Plus, Shimadzu, Japan) and a dark evaporation experiment, respectively. The compressive strength of wood was measured by a universal testing machine (UTM6530, China). The type of water in the woody biomass framework was characterized by low-field nuclear magnetic resonance (1D/2D LFNMR, VTM20-010V-I, China). Solar Evaporation Experiment: A 300 W xenon lamp (PLS-SXE3000, China) with an AM 1.5G filter was used to simulate sunlight, and a densitometer (CELNP2000-2(10)A, China) was used to adjust the radiation intensity at the evaporation interface to one sunlight (about 1 kW m -2 ). The surface temperature of the woody biomass-based evaporator and water temperature were recorded with an infrared thermal imager (FLIR-E4, USA). Mass changes during evaporation were measured using an electronic balance (BSM-220.4, China) with an accuracy of 0.0001 g. The evaporation rate (v) was calculated in equation (1) as follows: v=Δm/s*Δt (1) Where Δm was the overall mass change, s was the area at the top of the evaporator, and Δt was the irradiation time change. The photothermal conversion efficiency ( η ) of the evaporator was calculated by equation (2) as follows: η =v*H E /(C opt *P i ) (2) Where ν was the evaporation rate at a steady state, H E was the evaporation enthalpy of water in the corresponding sample, C opt was the light absorption coefficient of the evaporator surface as shown in Fig. 3g , and P i was the radiant power of one sun (1 kW m -2 ). In addition, the water vapour generated by the evaporator was collected by a self-made device ( Fig. 5c and S21 ) to measure the purification capacity of the evaporator. An inductively coupled plasma source mass spectrometer (ICP-MS, Agilent 7800ce, USA) was used to measure the concentration of metal ions in water, while the concentration of dyes in water was measured by an ultraviolet spectrophotometer (UV-2450, Japan). Declarations Acknowledgements This work was supported by the National Natural Science Foundation of China (22308029), the Knowledge Innovation Program of Wuhan-Basi Research (2023020201010072), the Fundamental Research Funds for the Central Universities (691000003), and the 5·5 Engineering Research & Innovation Team Project of Beijing Forestry University (No. BLRC 2023B05). Additionally, the authors appreciate the assistance of the Innovation Platform for High-Value Utilization of Forest Resources at Beijing Forestry University. Author contributions T.Y., C.C., X.S. and B.W. conceived the concept, processing, and structure details. B.W., Y.H. and Z.Y. performed the design and preparation of the evaporator. B.W. and Y.H. carried out the evaporation test. B.W., Z.Y., and Y.H. co-wrote the manuscript. T.Y., C.C. and X.S. supervised the work and revised the manuscript. J.L.W. provided guidance on the structural analysis of lignocellulose. Q.S. provided assistance in the enthalpy of the evaporation test of water. J.M.W. and X.Z. participated in large-scale sample preparation and outdoor evaporation tests. All authors commented on the submitted version of the manuscript. Competing interests The authors declare no competing interests. References Shannon, M. A. et al. Science and technology for water purification in the coming decades. Nature 452 , 301-310 (2008). Kim, Y. & Lee, W.-g. Seawater and its resources. In: Seawater batteries: principles, materials and technology ). Springer, 1-35 (2022). Chaule, S. et al. Rational design of a high performance and robust solar evaporator via 3D‐printing technology. Adv. Mater. 33 , 2102649 (2021). Chen, C., Kuang, Y. & Hu, L. Challenges and opportunities for solar evaporation. Joule 3 , 683-718 (2019). Tao, P. et al. Solar-driven interfacial evaporation. Nat. Energy 3 , 1031-1041 (2018). Wu, X. et al. Interfacial solar evaporation: from fundamental research to applications. Adv. Mater. , 2313090 (2024). He, S. et al. Nature-inspired salt resistant bimodal porous solar evaporator for efficient and stable water desalination. Energy Environ. Sci. 12 , 1558-1567 (2019). Chen, L. et al. 3D-printed tripodal porous wood-mimetic cellulosic composite evaporator for salt-free water desalination. Compos. Part. B-Eng. 263 , 110830 (2023). Chao, W. et al. Enhanced wood-derived photothermal evaporation system by in-situ incorporated lignin carbon quantum dots. Chem. Eng. J. 405 , 126703 (2021). Xu, N. et al. Flatband λ-Ti 3 O 5 boosts solar evaporation. Joule 7 , 2665-2667 (2023). Li, L. et al. Polyelectrolyte hydrogel‐functionalized photothermal sponge enables simultaneously continuous solar desalination and electricity generation without salt accumulation. Adv. Mater. , 2401171 (2024). Zhao, F. et al. Highly efficient solar vapour generation via hierarchically nanostructured gels. Nat. nanot. 13 , 489-495 (2018). Ma, X. et al. Wood-based solar-driven interfacial evaporators: Design and application. Chem. Eng. J. , 144517 (2023). Chen, L. et al. Biomass waste-assisted micro (nano) plastics capture, utilization, and storage for sustainable water remediation. The Innovation 5 , 100655 (2024). Petridis, L. & Smith, J. C. Molecular-level driving forces in lignocellulosic biomass deconstruction for bioenergy. Nat. Rev. Chem. 2 , 382-389 (2018). Thybring, E. et al. Water in wood: a review of current understanding and knowledge gaps. Forests 13 , 2051 (2022). Dong, Y. et al. Reviewing wood-based solar-driven interfacial evaporators for desalination. Water Res. 223 , 119011 (2022). Gnanasekaran, A. & Rajaram, K. Flake-like CuO nanostructure coated on flame treated eucalyptus wood evaporator for efficient solar steam generation at outdoor conditions. Colloid. Surface. A. 662 , 130975 (2023). Wu, W. et al. Cellulose‐based interfacial solar evaporators: structural regulation and performance manipulation. Adv. Funct. Mater. 33 , 2302351 (2023). Li, X. P. et al. Reshapable MXene/graphene oxide/polyaniline plastic hybrids with patternable surfaces for highly efficient solar‐driven water purification. Adv. Funct. Mater. 32 , 2110636 (2022). Wang, B. et al. Harnessing renewable lignocellulosic potential for sustainable wastewater purification. Research 7 , 0347 (2024). Tran, C. D. et al. Sustainable energy‐storage materials from lignin–graphene nanocomposite‐derived porous carbon film. Energy Technol. 5 , 1927-1935 (2017). Okamoto, S. et al. Additive effect of graphene and lignin‐derived graphene on radical polymerization behaviors of methacrylate monomers. Macromol. Chem. Phys. 224 , 2300276 (2023). Lin, J. et al. Laser-induced porous graphene films from commercial polymers. Nat. Commun. 5 , 5714 (2014). Yang, Z. et al. One-step sustainable preparation of laser induced S-doped graphene for assembly of high-performance supercapacitors. J. Clean. Prod. 450 , 141956 (2024). Gu, Y. et al. Solar‐powered high‐performance lignin‐wood evaporator for solar steam generation. Adv. Funct. Mater. 33 , 2306947 (2023). Zhao, F. et al. Materials for solar-powered water evaporation. Nat. Rev. Mater. 5 , 388-401 (2020). Wei, D. et al. Water activation in solar‐powered vapor generation. Adv. Mater. 35 , 2212100 (2023). Gnanasekaran, A. & Rajaram, K. Rational design of different interfacial evaporators for solar steam generation: Recent development, fabrication, challenges and applications. Renew. Sust. Energ. Rev. 192 , 114202 (2024). Zeng, Y. et al. Lignin plays a negative role in the biochemical process for producing lignocellulosic biofuels. Curr. Opin. Biotechnol. 27 , 38-45 (2014). Giummarella, N. et al. A critical review on the analysis of lignin carbohydrate bonds. Green Chem. 21 , 1573-1595 (2019). Wang, J. et al. Atomic force microscopy and molecular dynamics simulations for study of lignin solution self‐assembly mechanisms in organic–aqueous solvent mixtures. ChemSusChem 13 , 4420-4427 (2020). Hackenstrass, K., Hasani, M. & Wohlert, M. Structure, flexibility and hydration properties of lignin dimers studied with Molecular Dynamics simulations. Holzforschung 78 , 98-108 (2024). Xuemin, G., Peng, Y. & Yanfen, W. How to reduce enthalpy in the interfacial solar water generation system for enhancing efficiency? Nano Ener. , 109434 (2024). Jing, S. et al. The critical roles of water in the processing, structure, and properties of nanocellulose. ACS nano 17 , 22196-22226 (2023). Jia, L. et al. Crystal plane engineering to boost water cluster evaporation for enhanced solar steam generation. Nano Lett. 24 , 1753-1760 (2024). Engelund, E. T. et al. A critical discussion of the physics of wood–water interactions. Wood. Sci. Technol. 47 , 141-161 (2013). Bonnet, M. et al. NMR determination of sorption isotherms in earlywood and latewood of Douglas fir. Identification of bound water components related to their local environment. Holzforschung 71 , 481-490 (2017). Li, J. & Ma, E. Characterization of water in wood by time-domain nuclear magnetic resonance spectroscopy (TD-NMR): a review. Forests 12 , 886 (2021). Kuang, Y. et al. A high‐performance self‐regenerating solar evaporator for continuous water desalination. Adv. Mater. 31 , 1900498 (2019). Zhang, W. et al. Lignin laser lithography: a direct‐write method for fabricating 3D graphene electrodes for microsupercapacitors. Adv. Energy Mater. 8 , 1801840 (2018). Zhang, C. et al. An integrated and robust plant pulse monitoring system based on biomimetic wearable sensor. npj Flex. Electron. 6 , 43 (2022). Wu, J.-B. et al. Raman spectroscopy of graphene-based materials and its applications in related devices. Chem. Soc. Rev. 47 , 1822-1873 (2018). Xie, Z. et al. The rise of 2D photothermal materials beyond graphene for clean water production. Adv. Sci. 7 , 1902236 (2020). Mohan, V. B. et al. Graphene-based materials and their composites: A review on production, applications and product limitations. Compos. Part. B-Eng. 142 , 200-220 (2018). Yang, Z. et al. A solely biobased strain sensor with an ultra-precision response via a surface graphitization strategy. J. Mater. Chem. A 11 , 24928-24938 (2023). Pang, B. et al. Molecular‐scale design of cellulose‐based functional materials for flexible electronic devices. Adv. Electron. Mater. 7 , 2000944 (2021). Du, C. et al. Heat-localized solar evaporation: Transport processes and applications. Nano Ener. 107 , 108086 (2023). Lin, X. et al. Fully lignocellulosic biomass‐based double‐layered porous hydrogel for efficient solar steam generation. Adv. Funct. Mater. 32 , 2209262 (2022). Sluiter, A. et al. Determination of structural carbohydrates and lignin in biomass. Laboratory analytical procedure 1617 , 1-16 (2008). Additional Declarations There is NO Competing Interest. Supplementary Files SupportingInformation.docx Supporting Information Cite Share Download PDF Status: Published Journal Publication published 10 Mar, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7392399","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":509270134,"identity":"f7d4d2d1-b7d1-4fc1-af5b-04beccee38fb","order_by":0,"name":"Chaoji 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1","display":"","copyAsset":false,"role":"figure","size":1566974,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSchematic diagram of the preparation and internal mechanism of the woody biomass-based solar evaporator. a\u003c/strong\u003e Schematic diagram of lignin-engineered reconstituted woody framework strategy. \u003cstrong\u003eb\u003c/strong\u003eThe dual functions of lignin within woody biomass-based solar evaporators in water management and thermal management.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7392399/v1/31e94318c32e9680bf11aa68.png"},{"id":90569147,"identity":"081b1f26-fac0-4576-9bfa-46eed192613b","added_by":"auto","created_at":"2025-09-04 08:06:56","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1944117,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eExcellent water management for wood with an appropriate amount of lignin.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Schematic diagram of the interaction between water and molecular chains in W-150 and the water states. The final state models of \u003cstrong\u003eb\u003c/strong\u003e) W-A, and \u003cstrong\u003ec\u003c/strong\u003e) W-150 through Visual Molecular Dynamics. \u003cstrong\u003ed \u003c/strong\u003eThe proportion of the structural unit calculated based on the quantitative 2D-HSQC spectrum\u003cstrong\u003e. e\u003c/strong\u003e The ratio of intermediate water (IW) to free water (FW) obtained through molecular dynamics simulation calculation. \u003cstrong\u003ef\u003c/strong\u003e The hydrogen bond lifetimes of water molecules obtained through molecular dynamics simulation calculation. \u003cstrong\u003eg\u003c/strong\u003e Evaporation enthalpy of water in W-A and W-150 measured by the dark evaporation experiment. \u003cstrong\u003eh\u003c/strong\u003e T\u003csub\u003e2\u003c/sub\u003e distribution of W-A and W-150 in the fiber saturated state. T\u003csub\u003e1\u003c/sub\u003e-T\u003csub\u003e2\u003c/sub\u003e correlation spectra of \u003cstrong\u003ei\u003c/strong\u003e) W-A, and \u003cstrong\u003ej\u003c/strong\u003e) W-150 in the fiber saturated state.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7392399/v1/fd16371bcdd1d3846386618f.png"},{"id":90569144,"identity":"55e699e7-160e-4fd9-a62a-84b2424dd1f5","added_by":"auto","created_at":"2025-09-04 08:06:56","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":2358103,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCharacterization of the structure and light absorption performance of the top layer. a\u003c/strong\u003eSchematic diagram of graphene preparation by laser etching of lignin. \u003cstrong\u003eb\u003c/strong\u003eSurface wettability of C-150 and E-150. \u003cstrong\u003ec\u003c/strong\u003e SEM comparison images before and after laser etching. \u003cstrong\u003ed\u003c/strong\u003e SEM image of a cross-section of the E-150 surface. \u003cstrong\u003ee\u003c/strong\u003e SEM and HR-TEM images of the E-150 surface at different scales. \u003cstrong\u003ef\u003c/strong\u003e Raman spectra of the E-150 photothermal conversion layer. \u003cstrong\u003eg\u003c/strong\u003eSolar absorptivity of woody biomass-based solar evaporators and the normalized spectral solar irradiance density of air mass 1.5 global (AM 1.5 G) tilt solar spectrum. \u003cstrong\u003eh\u003c/strong\u003e Large laser-etched woody biomass-based solar evaporator.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNote\u003c/strong\u003e: C-150 was the W-150 coated with lignin solution; E-150 represented the woody biomass-based solar evaporator obtained by laser etching of the C-150.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7392399/v1/fb3501bb22be791b460be79b.png"},{"id":90569152,"identity":"faa40b6f-443b-4668-90c9-988e16a3d740","added_by":"auto","created_at":"2025-09-04 08:06:56","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1734765,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe evaporation performance of lignin-engineered recombinant wood. a \u003c/strong\u003eEvaporation rate curves of E-W, E-A and E-150 under one solar irradiation. \u003cstrong\u003eb\u003c/strong\u003e Stable evaporation rates of woody biomass-based solar evaporators with different lignin content under one solar irradiation (All evaporators were prepared based on W-150, with the X in E-X representing laser power). \u003cstrong\u003ec\u003c/strong\u003e Effect of laser power on the evaporation rate of the woody biomass-based solar evaporator. \u003cstrong\u003ed\u003c/strong\u003ePhotothermal conversion efficiencies of E-W, E-A and E-150 under one solar irradiation. \u003cstrong\u003ee \u003c/strong\u003eComparison with previously reported woody biomass-based solar evaporators in terms of evaporation rate and photothermal conversion efficiency under one solar irradiation, and the detailed data are shown in Table S3. \u003cstrong\u003ef\u003c/strong\u003eA comprehensive comparison with previously reported woody biomass-based solar evaporators with excellent performance. \u003cstrong\u003eg\u003c/strong\u003eThe infrared thermal images of the E-150 surface temperature with time.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7392399/v1/4b3e949a8b882d5e855b1cdc.png"},{"id":90570480,"identity":"daca5537-4365-4402-a6b4-201f48266fae","added_by":"auto","created_at":"2025-09-04 08:22:56","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1462639,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMultifunctional performance of lignin-engineered reconstituted wood: salt resistance, recyclability, and purification. a\u003c/strong\u003e Evaporation rate of E-150 in brines with different salinities under one solar radiation. \u003cstrong\u003eb\u003c/strong\u003e Schematic diagram for resistance to salt crystallization of E-150. \u003cstrong\u003ec\u003c/strong\u003e The outdoor water evaporation experiment of E150. \u003cstrong\u003ed\u003c/strong\u003e synchronous solar flux, and evaporation rates of E-150 from 8:00 to 17:00 in the outdoor experiment (Beijing, China, September 20, 2024). \u003cstrong\u003ee\u003c/strong\u003e The change in evaporation rate of E-150 in real seawater after continuous evaporation for 12 h under one solar radiation, and the salt crystallization after continuous evaporation for 12 h as shown in the illustration. \u003cstrong\u003ef \u003c/strong\u003eImages of the E-A and E-150 before and after recycling. \u003cstrong\u003eg\u003c/strong\u003e Average evaporation rate of E-150 in real seawater for 10 consecutive 4 h under one solar radiation.\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7392399/v1/4fa0d4bb9a56cbe3144f084e.png"},{"id":107696304,"identity":"a251e78d-4179-4f36-8c59-b2c84d586376","added_by":"auto","created_at":"2026-04-24 07:10:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":10105083,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7392399/v1/d1ced4ab-3e96-44a0-a22c-c004fe572616.pdf"},{"id":90570257,"identity":"b8008a9f-e427-49b5-bb63-53ce798294f2","added_by":"auto","created_at":"2025-09-04 08:14:56","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":10553711,"visible":true,"origin":"","legend":"Supporting Information","description":"","filename":"SupportingInformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-7392399/v1/53733cf3cfeb9cd555b5fd74.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Compositional and Structural Reconstitution of Woody Biomass Framework via Dual-Functional Lignin Engineering Toward Efficient and Salt-Resistant Solar Desalination","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe escalating global water crisis – driven by population growth, industrialization and climate change – has rendered freshwater increasingly scarce.\u003csup\u003e1\u003c/sup\u003e Seawater, which makes up nearly 97.5% of the Earth's water resources, is a viable source, particularly for coastal regions facing severe freshwater shortages, but conventional desalination methods (reverse osmosis or multistage flash) are energy-intensive and costly\u003csup\u003e2,3\u003c/sup\u003e.\u0026nbsp;In contrast, interfacial solar evaporation offers a promising alternative: it harnesses highly renewable solar energy to heat only a thin surface layer of water, minimizing thermal losses and operational complexity\u003csup\u003e4\u003c/sup\u003e. This approach can transform seawater and wastewater into drinkable water in a low-cost, eco-friendly manner, which is critical for coastal and arid regions facing chronic freshwater shortages. Interfacial solar evaporation typically consists of a photothermal top layer that absorbs sunlight and an underlying wick or porous matrix\u0026nbsp;that transports water upward\u003csup\u003e5\u003c/sup\u003e\u003csup\u003e,\u0026nbsp;\u003c/sup\u003e\u003csup\u003e6\u003c/sup\u003e. Wood, being\u0026nbsp;an abundant and renewable natural product,\u0026nbsp;possesses\u0026nbsp;a layered porous structure with low-curvature channels\u0026nbsp;capable of floating on water\u003csup\u003e7,8\u003c/sup\u003e.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eCombined with anisotropic thermal conduction across cross-section and longitudinal sections,\u0026nbsp;wood\u0026nbsp;holds\u0026nbsp;significant potential for application in interfacial solar evaporation\u003csup\u003e9\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eState-of-the-art materials have pushed photothermal conversion toward the thermodynamic limit, so further gains depend on improved water management\u003csup\u003e10\u003c/sup\u003e. In particular, recent work (inspired by hydrogel evaporators) has shown that creating a higher fraction of loosely bound intermediate water via structural or chemical tuning, which can dramatically lower the evaporation enthalpy and boost evaporation rates\u003csup\u003e11,12\u003c/sup\u003e.\u0026nbsp;However, native wood contains hydrophobic lignin that tightly binds cellulose fibers together, which tends to impede the pumping of water to the evaporation interface. Many reported wood evaporators therefore chemically remove lignin from wood to open its pores and increase wettability\u003csup\u003e13,14\u003c/sup\u003e.\u0026nbsp;However,\u0026nbsp;complete removal of lignin has drawbacks: it entirely consumes the lignin resource and, importantly, eliminates the only intrinsic hydrophobic component of wood. As a result, excessive hydrophilicity leads to domination by high-enthalpy water (combined water and free water), and limits the ultimate evaporation rate\u003csup\u003e15\u003c/sup\u003e. Recent molecular simulations and experiments confirm that introducing an appropriate amount of hydrophobic components can help create more intermediate water with low evaporation enthalpy by weakening the hydrogen bond network between the matrix and water\u003csup\u003e16\u003c/sup\u003e.\u0026nbsp;Therefore, as the only hydrophobic component and binder in wood, the controlled presence of lignin\u0026nbsp;can actually be leveraged to water states inside wood from both spatial and chemical composition perspectives.\u0026nbsp;Adjusting the lignin content in wood to maintain effective water pumping capacity while increasing the intermediate moisture content paves the way for high-performance woody biomass-based solar evaporators with superior economic and environmental benefits, making them more suitable for large-scale application than hydrogel solar evaporators.\u003c/p\u003e\n\u003cp\u003eAnother challenge in woody biomass-based evaporators is achieving efficient photothermal conversion while maintaining sustainability. Natural wood is weakly absorptive of sunlight, so most designs deposit external coatings (e.g. plasma metal nanoparticles or semiconductor inks) to boost absorption\u003csup\u003e17,18\u003c/sup\u003e. These additives can add cost and environmental risk, conflicting with the goal of green desalination. Carbon-based nanomaterials, especially graphene, have been widely used in the photothermal conversion system of woody biomass-based solar evaporators due to their excellent broad-spectrum absorption, outstanding photothermal conversion efficiency, strong stability and high abundance\u003csup\u003e19,20\u003c/sup\u003e.\u0026nbsp;Notably, lignin, with its unique aromatic ring structure and high carbon content\u003csup\u003e21\u003c/sup\u003e,\u0026nbsp;can\u0026nbsp;promote the formation of sp\u003csup\u003e2\u003c/sup\u003e hybrid ordered structure of graphene crystals, making it an ideal raw material for preparing graphene\u003csup\u003e22,23\u003c/sup\u003e.\u0026nbsp;However, cumbersome processes and harsh preparation conditions limit the large-scale development of lignin-based graphene.\u0026nbsp;Laser etching technology, with the advantages of simple operation, low cost, high precision, energy saving and environmental protection\u003csup\u003e24\u003c/sup\u003e, can ignore the the severe heterogeneity of lignin, promoting the sustainable development of lignin-based photothermal conversion materials\u003csup\u003e25\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eIn this work, we developed a lignin-engineered reconstituted woody framework strategy that simultaneously addresses two key challenges in solar evaporation based on sustainability and economy: the efficient preparation of high-performance photothermal layers and the reduction of water evaporation enthalpy (\u003cstrong\u003eFig. 1\u003c/strong\u003e). Theoretical simulations and experimental results reveal that appropriate lignin removal modulates both the spatial microstructure and the distribution of functional groups, promoting the formation of intermediate water with weaker hydrogen bonding. This lowers the evaporation enthalpy while preserving effective water transport to the evaporation interface. Simultaneously, the removed lignin is not wasted, which is recovered and processed via laser etching into a composite carbon layer composed of graphite carbon and graphene. This carbon layer exhibits a hierarchically ordered porous architecture (micronscale macropores enhance the capture of incident light, while mesopores and micropores efficiently absorb scattered and reflected light), resulting in solar absorptivity exceeding 95%. Moreover, the high specific surface area of the porous carbon layer, combined with the presence of graphene domains, increases the density of photothermal conversion sites and further enhances overall conversion efficiency. As a result, the resulting evaporator E-150 demonstrated an evaporation rate of up to 2.24 kg m\u003csup\u003e-2\u003c/sup\u003e h\u003csup\u003e-1\u003c/sup\u003e and a photothermal conversion efficiency of 91.52% with minimal processing. This lignin-engineered reconstitution wood not only outperforms most reported woody biomass-based solar evaporators in terms of evaporator performance but also has outstanding environmental and economic benefits, which holds great promise for promoting the large-scale application of woody biomass-based solar evaporators.\u003c/p\u003e\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"},{"header":"Water states within the lignin-engineered reconstituted wood","content":"\u003cp\u003eAs shown in \u003cstrong\u003eFig. S1\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eTable S1\u003c/strong\u003e, the lignin content decreased from 25.77% in natural wood (labelled as Wood) to 16.70% in W-150 obtained after pretreatment with an alcohol solution system at 150 \u003csup\u003eo\u003c/sup\u003eC. In contrast, the lignin in W-A, obtained by sodium chlorite delignification, was almost completely removed. The hydrophilicity of the woody biomass framework significantly affects water pumping capacity and water states\u003csup\u003e26\u003c/sup\u003e. The hydrophilicity of W-150 improved due to partial removal of the hydrophobic lignin, while W-A, lacking lignin, exhibited superior hydrophilicity (\u003cstrong\u003eFig. S2\u003c/strong\u003e). The increase in the hydrophilicity of the woody biomass framework facilitates the water pumping to the evaporation interface. However, previous reports have shown that excessive hydrophilicity will lead to the dominance of free water, which has a high evaporation enthalpy (about 86 times the enthalpy of intermediate water), thereby limiting the further evaporation rate\u003csup\u003e27,28,29\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe influence of lignin on the water states within the woody biomass framework stems from two perspectives (\u003cstrong\u003eFig. 2a\u003c/strong\u003e). Firstly, lignin, as a main component of lignocellulose, is entangled with cellulose and hemicellulose via complex lignin–carbohydrate complex (LCC) bonds\u003csup\u003e30,31\u003c/sup\u003e. Therefore, lignin content closely affects the crosslinking degree of the woody biomass framework. Based on these chemical composition analysis results, final-state models of each simulation system were constructed using Visual Molecular Dynamics (VMD). Compared to the Wood (\u003cstrong\u003eFig. S3\u003c/strong\u003e) and the W-A (\u003cstrong\u003eFig. 2b\u003c/strong\u003e), the W-150 system (\u003cstrong\u003eFig. 2c\u003c/strong\u003e) is more homogeneous and compact (as evidenced by its smaller cyclotron radius, \u003cstrong\u003eFig. S4\u003c/strong\u003e). This suggests that the W-150 system has less void space that is prone to generating free water, thereby providing spatial conditions favorable for the generation of more intermediate water. On the other hand, lignin contains both hydrophilic functional groups (such as hydroxyl and carboxyl groups), as well as hydrophobic phenyl ring structures (the only hydrophobic component in lignocellulose). That affects the formation of hydrogen bonds between the woody biomass framework and water molecules in a moist state, thus impacting the number and strength of those hydrogen bonds. Crucially, pretreatment selectively enriched syringyl (S) units in lignin of W-150 (L-W150), elevating the S/G ratio from 2.31 in lignin of Wood (L-Wood) to 5.05 in L-W150 (\u003cstrong\u003eFigs. 2d and S5\u003c/strong\u003e). The aromatic ring of S-units bears two methoxy groups and one phenolic hydroxyl group, providing increased density of hydrogen-bond acceptors and donors. While their polar functional groups facilitate water adsorption, the inherent hydrophobicity of the aromatic ring prevents excessive hydrophilicity that would generate tightly bound water\u003csup\u003e32\u003c/sup\u003e. Furthermore, the symmetric distribution of methoxy groups in S-units creates a uniform polar microenvironment. This configuration stabilizes intermediate water layers through a multi-site network of weak-to-moderate hydrogen bonds that entrap water molecules\u003csup\u003e33\u003c/sup\u003e. Consequently, the enhanced S/G ratio in L-W150 is anticipated to promote greater generation of intermediate water. To this end, molecular dynamics simulations were conducted to model the interactions between the lignocellulosic molecular chains and water (the Wood sample was excluded from further analysis due to its poor water-pumping capability). The results (\u003cstrong\u003eFig. S6\u003c/strong\u003e) show that, compared with W-A, W-150 has a higher proportion of intermediate water (\u003cstrong\u003eFig. 2e\u003c/strong\u003e) and a shorter lifetimes of water hydrogen bonds (\u003cstrong\u003eFig. 2f\u003c/strong\u003e). This indicates that appropriately retained lignin can facilitate the formation of intermediate water via weak hydrogen bonding and reduce the difficulty of evaporating water clusters (\u003cstrong\u003eFig. S8\u003c/strong\u003e), thereby lowering the enthalpy of water evaporation.\u003c/p\u003e\u003cp\u003eTo validate these theoretical calculation findings, differential scanning calorimetry (DSC), dark evaporation experiments, Raman and low field nuclear magnetic resonance (LF-NMR) were systematically employed to investigate the effect of lignin on the water states and the evaporation enthalpy of water in woody biomass frameworks. As shown in \u003cstrong\u003eFig. S9a\u003c/strong\u003e, the DSC curve of pure water showed a sharp peak. The water peak in W-A flattened out, but still had sharp peaks, indicating too much free water. In W-150, the water appeared broader and lacked sharp peaks. The evaporation enthalpies of water in pure W-A and W-150 calculated from the DSC curve were 1990 and 1670 J/g, respectively (\u003cstrong\u003eFig. S9b\u003c/strong\u003e). In the dark evaporation experiment, as shown in \u003cstrong\u003eFig. 2g\u003c/strong\u003e, the evaporation enthalpies of water in W-A and W-150 were 1842 and 1397 J/g, respectively. The results of both methods showed that proper lignin content was beneficial in reducing the evaporation enthalpy of water. However, it was found that the evaporation enthalpy obtained by the DSC curve was higher than that obtained by the dark evaporation experiment, because the DSC method also involves the evaporation of bound water besides intermediate water and free water.\u003c/p\u003e\u003cp\u003eTo further explore the effect of lignin content on the evaporation enthalpy of water in the wood, woody biomass frameworks with different lignin content were obtained under the pretreatment condition of 140-170 \u003csup\u003eo\u003c/sup\u003eC. The evaporation enthalpy of water in the woody biomass framework obtained by DSC increased with the decrease in lignin content, and W-140 had the lowest evaporation enthalpy (\u003cstrong\u003eFig. S9b\u003c/strong\u003e). However, the evaporation enthalpy of water obtained by the dark evaporation experiment decreased first and then increased with the decrease of lignin content, and W-150 had the lowest evaporation enthalpy (\u003cstrong\u003eFig. S9c\u003c/strong\u003e). The difference between the two results stemmed from the fact that W-150, with lower lignin content, had better hydrophilicity and more bound water than W-140, resulting in a higher evaporation enthalpy obtained by DSC. It is worth noting that the actual use of solar evaporators almost does not involve the evaporation of bound water, which is closer to the dark evaporation experiment\u003csup\u003e34\u003c/sup\u003e. Therefore, the results of the dark evaporation experiment were used as the basis for the subsequent discussion.\u003c/p\u003e\u003cp\u003eLF-NMR were used to investigate spin proton relaxation, providing information on the nuclear mobility of bound and free water\u003csup\u003e20\u003c/sup\u003e. The transversal relaxation properties of water in the woody biomass framework were investigated by 1D LF-NMR, which attempted to explain the influence mechanism of lignin content on water states in wood. Generally, the water that is more tightly bound to the wood (such as bound water) has a shorter transverse relaxation time (T\u003csub\u003e2\u003c/sub\u003e); conversely, the free water has a longer T\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e20\u003c/sup\u003e. As shown in \u003cstrong\u003eFig. S10a\u003c/strong\u003e, the T\u003csub\u003e2\u003c/sub\u003e distribution curve of Wood showed four peaks, indicating the presence of four water states. Relaxation peaks of T\u003csub\u003e2\u003c/sub\u003e less than 1 ms (T\u003csub\u003e21\u003c/sub\u003e) and around 1000 ms (T\u003csub\u003e24\u003c/sub\u003e) are attributed to bound and free water, respectively\u003csup\u003e35,36\u003c/sup\u003e. Large amounts of capillary water were present in extremely fine channels in the wood, which appeared at the T\u003csub\u003e23\u003c/sub\u003e relaxation peak near 45 ms,\u003csup\u003e37\u003c/sup\u003e while acromion (T\u003csub\u003e23\u003c/sub\u003e) might be intermediate water in the large diameter channels. It was found that the content of bound and free water in W-A increased, but the T\u003csub\u003e22\u003c/sub\u003e peak belonging to intermediate water disappeared (\u003cstrong\u003eFig. 2h\u003c/strong\u003e), indicating that the absence of lignin was not conducive to the formation of intermediate water. As for W-150, the T\u003csub\u003e22\u003c/sub\u003e and T\u003csub\u003e23\u003c/sub\u003e peaks were combined, showing that the properties of capillary water at this time were very similar to those of intermediate water. However, capillary water is difficult to distinguish between bound water and intermediate water through 1D LF-NMR.\u003c/p\u003e\u003cp\u003eTo further subdivide capillary water, 2D LF-NMR was used to characterize the water states in the woody biomass framework, which effectively reduces the interference caused by water overlap and chemical composition. The longitudinal relaxation time (T\u003csub\u003e1\u003c/sub\u003e) can reflect the time for the nuclei of high-energy states to return to the ground state through energy exchange with the surrounding environment during relaxation, while T\u003csub\u003e2\u003c/sub\u003e corresponds to the time it takes for a high-energy nucleus to transfer energy to a similar low-energy nucleus and return to the ground state\u003csup\u003e38\u003c/sup\u003e. The T\u003csub\u003e1\u003c/sub\u003e/T\u003csub\u003e2\u003c/sub\u003e value indicates the mobility of hydrogen atoms, and a lower value means that the water molecule is more mobile. As shown in\u003cstrong\u003e\u0026nbsp;Fig. S10b\u003c/strong\u003e, four main peaks could be observed in the 2D LF-NMR spectrum of Wood, among which the D peak with the largest T\u003csub\u003e1\u003c/sub\u003e/T\u003csub\u003e2\u003c/sub\u003e value is usually identified as the signal of polymers or bound water in wood, while the A peak with the smallest T\u003csub\u003e1\u003c/sub\u003e/T\u003csub\u003e2\u003c/sub\u003e value represents free water. Peaks B and C originated from capillary water, which corresponded to the water in the amorphous region of microfibrils and its surrounding hemicellulose, as well as the water in the amorphous region of the hemicellulose and lignin, respectively\u003csup\u003e39\u003c/sup\u003e. Since lignin and hemicellulose were almost completely removed, no peak C appeared in the 2D LF-NMR spectrum of W-A, and a strong peak A was observed (\u003cstrong\u003eFig. 2i\u003c/strong\u003e). The stronger peak A and the weaker peak B indicated that capillary water in W-A had similar properties to free water. Notably, a strong peak B was observed in the 2D LF-NMR spectrum of W-150, which were further divided into peaks B\u003csub\u003e1\u003c/sub\u003e and B\u003csub\u003e2\u003c/sub\u003e to distinguish better the capillary water states (\u003cstrong\u003eFig. 2j\u003c/strong\u003e). The peak B\u003csub\u003e2\u003c/sub\u003e with a smaller T\u003csub\u003e1\u003c/sub\u003e/T\u003csub\u003e2\u003c/sub\u003e value had better water mobility, indicating that water molecules were clustered under the action of hydrogen bonds, which was not conducive to water evaporation. The water in peak B1 was judged as intermediate water. Compared with W-A and Wood, the B\u003csub\u003e1\u003c/sub\u003e signal in W-150 was significantly enhanced, which meant that W-150 had more intermediate water. Moreover, to be closer to the actual use scenario, 2D LF-NMR tests were performed on W-A and Wood in a water-filled state. As shown in \u003cstrong\u003eFig. S11\u003c/strong\u003e, only one strong peak was shown in both spectra. By comparison, W-150 had a larger T\u003csub\u003e1\u003c/sub\u003e/T\u003csub\u003e2\u003c/sub\u003e value than W-A, which once again verified that W-150 had a larger intermediate water content.\u003c/p\u003e\u003cp\u003eTo prove the existence of different water forms, Raman spectroscopy of various woody biomass frameworks was fitted into four peaks by the Gaussian function, as shown in \u003cstrong\u003eFig. S12\u003c/strong\u003e. The results showed that W-150 presented the largest ratio of intermediate water to free water due to the proper delignification, consistent with the analysis of evaporation enthalpy and LF-NMR. Moreover, note that since a certain amount of lignin was still retained as a support, the multistage channels in W-150 were intact, especially the ray cells (\u003cstrong\u003eFig. S13\u003c/strong\u003e), which will facilitate the transverse shuttle of salt ions, protecting the salt resistance\u003csup\u003e40\u003c/sup\u003e. In summary, the hydrophilicity, functional group composition and crosslinking degree of the woody biomass framework were affected by lignin content. Appropriate lignin retention encouraged the production of more intermediate water in the woody biomass framework (especially in the capillary region), which could effectively pump water to the evaporation interface while reducing the evaporation enthalpy, thereby increasing the evaporation rate (\u003cstrong\u003eFig. 2c\u003c/strong\u003e). In addition, due to the partial retention of lignin, the multistage channel structure was preserved intact, which was conducive to salt resistance.\u003c/p\u003e"},{"header":"Laser-etched surfaces","content":"\u003cp\u003eThe lignin recovered during the ethanol solution pretreatment was coated on the surface of W-150, which was then laser etched to prepare the photothermal conversion layer of the evaporator (\u003cstrong\u003eFig. 3a\u003c/strong\u003e). After laser etching, the surface of the evaporator shows increased hydrophilicity (\u003cstrong\u003eFigs. 3b and S14\u003c/strong\u003e) and an orderly porous structure (\u003cstrong\u003eFig. 3c\u003c/strong\u003e). As shown in \u003cstrong\u003eFig. 3e\u003c/strong\u003e, compared with other carbonization technologies, the graphitized layer obtained by laser etching technology showed a satisfying surface morphology (rich, multi-layered and ordered hierarchical pores) and a specific surface area of up to 100.77 m\u003csup\u003e2\u003c/sup\u003e g\u003csup\u003e-1\u003c/sup\u003e(\u003cstrong\u003eFig. S15\u003c/strong\u003e). The micronscale macropores facilitate effective capture of incident sunlight, while the mesopores and micropores efficiently absorb scattered and reflected light. This hierarchically ordered porous architecture induces a pronounced blackbody effect, significantly enhancing broadband solar absorption and localized photothermal conversion. Moreover, the high specific surface area of the porous carbon layer promotes the formation of nan/microscale water droplets with a lower evaporation enthalpy on the surface, which will be proved in subsequent experiments.. Furthermore, regardless of the coating process or the laser etching process, the multistage channels and transversely shuttling ray cells in the woody biomass framework were retained (\u003cstrong\u003eFig. S16\u003c/strong\u003e), which would guarantee the anti-salt crystallization performance of E-150. Furthermore, the laser etching depth of close to 60 μm (\u003cstrong\u003eFig. 3d\u003c/strong\u003e) and the laser-induced graphene (LIG) observed inside the large channels within the woody biomass framework (\u003cstrong\u003eFig. S17\u003c/strong\u003e) would further promote sunlight absorption.\u003c/p\u003e\u003cp\u003eIn addition to the orderly porous structure, the LIG had a crystal region with a lattice spacing of 0.349 nm (\u003cstrong\u003eFig. 3e\u003c/strong\u003e), which could be attributed to the spacing of the two adjacent (002) planes in graphitic carbon\u003csup\u003e41\u003c/sup\u003e. Moreover, as shown in\u003cstrong\u003e\u0026nbsp;Fig. 3f,\u003c/strong\u003e three main peaks could be observed in the Raman spectrum of the E-150 surface. Among them, the D-peak (1340 cm\u003csup\u003e-1\u003c/sup\u003e) and G-peak (1570 cm\u003csup\u003e-1\u003c/sup\u003e) are attributed to lattice defects (sp\u003csup\u003e3\u003c/sup\u003e hybridization) of carbon atoms and in-plane stretching vibrations of sp\u003csup\u003e2\u003c/sup\u003e hybridization of carbon atoms, respectively\u003csup\u003e42\u003c/sup\u003e. The peak (2670 cm\u003csup\u003e-1\u003c/sup\u003e) comes from second-order band-boundary phonons, which are usually related to the number of graphene layers\u003csup\u003e43\u003c/sup\u003e. The distinct peak and small I\u003csub\u003eD\u003c/sub\u003e/I\u003csub\u003eG\u003c/sub\u003e value (0.69) indicated the presence of graphene with fewer stacked layers. However, there was still some sp\u003csup\u003e3\u003c/sup\u003e hybridization at the edges of the surface carbon layer. The results of the TEM and Raman analyses showed that both graphene and graphitic carbon were present in the surface carbon layer. Graphene can effectively absorb sunlight from the ultraviolet to infrared range and has excellent photothermal conversion efficiency and thermal conductivity\u003csup\u003e44\u003c/sup\u003e. However, the complex preparation process and the exorbitant price of graphene make it impractical to use the photothermal conversion layer composed only of graphene. Moreover, graphene usually requires support material to enhance its structural stability and mechanical strength, but the interface compatibility with the support material still faces difficulties\u003csup\u003e45\u003c/sup\u003e. In LIG, porous graphitic carbon served as a support material for graphene, which not only provided a high specific surface area to promote the absorption of sunlight, but also complements the disadvantages of graphene without having to consider interface compatibility issues to overcome the defects of limited light absorption efficiency and single light absorption direction of few-layer graphene monomers. Observing the changes of elements after laser etching showed that carbon elements increased and oxygen elements decreased significantly (\u003cstrong\u003eFig. S18\u003c/strong\u003e). Combined with the previous reports, the graphitization mechanism could be inferred as follows: due to the violent vibration within lignin molecules caused by laser radiation, the local temperature rapidly increased, resulting in C-O bond and C=O bond breaking and gas release (\u003cstrong\u003eFig. 3a\u003c/strong\u003e) \u003csup\u003e46\u003c/sup\u003e. At the same time, a part of the region underwent a transition from sp\u003csup\u003e3\u003c/sup\u003e hybridization state to sp\u003csup\u003e2\u003c/sup\u003e hybridization state, and the benzene ring structure of lignin was organized into a graphene structure. It was worth noting that untreated balsa wood had little carbonization effect on the surface of the wood substrate at the same laser power due to its low lignin content and the presence of LCC bonds (\u003cstrong\u003eFig. S19\u003c/strong\u003e).\u003c/p\u003e\u003cp\u003eThe ability of the evaporator's photothermal conversion layer to absorb sunlight was enhanced (\u003cstrong\u003eFig. S20\u003c/strong\u003e). As shown in \u003cstrong\u003eFig. S21\u003c/strong\u003e, compared with W-150, the light absorption capacity of C-150 in the short-wavelength band was increased due to the introduction of lignin, but there was almost no change in the long-wavelength band. Under the synergistic action of graphene and graphitic carbon, the light absorption capacity of E-150 in the full band of 300-2500 nm had been significantly improved, exhibiting an absorption rate of up to 95.48% for sunlight, which was much higher than that of the W-150 and C-150 (\u003cstrong\u003eFig. 3g\u003c/strong\u003e). The LIG (a composite material composed of graphene and porous graphitic carbon) obtained by laser etching of lignin showed outstanding sunlight absorption capacity and potentially excellent photothermal conversion efficiency. Furthermore, A simple process of this work is advantageous for the large-scale preparation of a reconstituted wood solar evaporator. According to the experimental conditions of this work, we further scaled up the production, achieving a large-sized evaporator of 0.88 m² or an evaporator of arbitrary shape to meet the requirements of complex practical conditions (\u003cstrong\u003eFigs. 3h\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;S22\u003c/strong\u003e).\u003c/p\u003e"},{"header":"Evaporation properties","content":"\u003cp\u003eBased on the above analysis, partial delignification significantly enhanced the intermediate water content. Moreover, LIG derived from recovered lignin on the surface of the evaporator demonstrated superior solar absorption and photothermal conversion efficiency. These characteristics established a solid foundation for the development of high-performance woody biomass-based solar evaporators. As shown in \u003cstrong\u003eFig. 4a\u003c/strong\u003e, woody biomass-based solar evaporators E-W, E-A and E-150 were prepared based on Wood, E-A and E-150, respectively, and evaporation rates were 1.51, 1.72 and 2.24 kg m\u003csup\u003e-2\u003c/sup\u003e h\u003csup\u003e-1\u003c/sup\u003e under one sunlight, respectively. Since the manufacturing process of the photothermal conversion layer was the same, the difference in evaporation rates was mainly due to the woody biomass framework. According to the analysis results in Section 2.1, the woody biomass framework of E-W contained a large amount of lignin, resulting in its insufficient ability to pump water to the evaporation interface, while the water within E-A was dominated by free water with high enthalpy of evaporation due to its excellent hydrophilicity. In the case of E-150, appropriate delignification increased the intermediate water content in the woody biomass framework while efficiently pumping water to the evaporation interface. Moreover, the photothermal conversion layer composed of graphite carbon and graphene not only had superior light absorption capacity and photothermal conversion efficiency, but also promoted the formation of microdroplets with low evaporation enthalpy in the pumped water (\u003cstrong\u003eFig. S23\u003c/strong\u003e), thus improving the evaporation performance. In addition, the comparison of woody biomass-based solar evaporators with different lignin content showed that the evaporation rate first increased and then decreased with the decrease of lignin content, and E-150 showed the highest evaporation rate (\u003cstrong\u003eFig. 4b\u003c/strong\u003e), which corresponded to the analysis results of intermediate water content.\u003c/p\u003e\u003cp\u003eBased on W-150, the influence of laser power on the evaporation performance was also discussed. As shown in \u003cstrong\u003eFigs. 4c and S24\u003c/strong\u003e, when the laser power was less than 45%, lignin could not be effectively graphitized, resulting in inferior light absorption performance and photothermal conversion efficiency of the evaporator surface. However, when the laser power was excessive (50%), Raman spectra showed a large I\u003csub\u003eD\u003c/sub\u003e/I\u003csub\u003eG\u003c/sub\u003e value and almost no 2D peaks could be observed (\u003cstrong\u003eFig. S25\u003c/strong\u003e). At this time, the surface of the evaporator was over-graphitized, mainly composed of graphite carbon, and almost no graphene structure. Therefore, achieving a composite carbon layer with the complementary advantages of graphite carbon and graphene was impossible, reducing light absorption and photothermal conversion capacity. Furthermore, the photothermal conversion capability of the evaporator was investigated by measuring the temperature change of the surface. \u003cstrong\u003eFig. 4g\u003c/strong\u003e showed that the temperature of the evaporator surface rapidly rose to 39.1 \u003csup\u003eo\u003c/sup\u003eC in 1 min under one solar irradiation, indicating the superior photothermal conversion capability of the E-150. After 30 min of irradiation, the temperature of the evaporator surface was stable at about 50 \u003csup\u003eo\u003c/sup\u003eC, and the water temperature was 31 \u003csup\u003eo\u003c/sup\u003eC, indicating a thermal localization effect, mainly due to the low thermal conductivity caused by the porous structure of the wood. The thermal localization effect could reduce the heat loss during evaporation and improve the evaporation performance.\u003csup\u003e47,48\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eDue to excellent water and thermal management, the E-150 exhibited an evaporation rate of up to 2.24 kg m\u003csup\u003e-2\u003c/sup\u003e h\u003csup\u003e-1\u003c/sup\u003e and a photothermal conversion efficiency of 91.52% under one solar irradiation (\u003cstrong\u003eFig. 4d\u003c/strong\u003e), surpassing most reported woody biomass-based solar evaporators (\u003cstrong\u003eFig. 4e and Table S3\u003c/strong\u003e). Although a few reported woody biomass-based solar evaporators have evaporation performance close to or better than the E-150, these preparation processes are complex and require the introduction of metals or metal oxides, which further increases their cost and potential environmental hazards. Furthermore, the introduction of new carbon dots can endow the evaporator with evaporation performance comparable to that of E-150, but the preparation of these carbon dots requires a large amount of reagents and a long processing time (over 20 hours), resulting in a low efficiency of evaporator preparation. Moreover, the introduction of new carbon dots can endow the evaporator with evaporation performance comparable to that of E-150, but the preparation process for these carbon dots requires a large amount of reagents and an extended period (over 20 h), leading to low efficiency in evaporator preparation. Different from these advanced woody biomass-based solar evaporators mentioned above, this work uses fully biomass-based materials, with a low energy consumption, short processing time, and no additional metal materials to prepare highly efficient woody biomass-based solar evaporators. This lignin-engineered reconstituted woody framework strategy offered simplicity in operation, high resource utilization, low energy consumption, and less pollution. Compared to reported woody biomass-based solar evaporators similar or better evaporation performance, it demonstrated superior environmental and economic benefits (\u003cstrong\u003eFig. 4f\u003c/strong\u003e). This highlights its exceptional potential for commercial application, underscoring its promising scalability and market viability in sustainable technology solutions.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"Seawater desalination and wastewater purification","content":"\u003cp\u003eSalt ions in seawater/sewage will concentrate, crystallize and accumulate during evaporation, resulting in salt pollution\u003csup\u003e49\u003c/sup\u003e. As shown in \u003cstrong\u003eFig. 5a\u003c/strong\u003e, the evaporation rate of E-150 in simulated brine with 3.5% and 5.0% salinity stabilized at about 2.15 kg m\u003csup\u003e-2\u003c/sup\u003e h\u003csup\u003e-1\u003c/sup\u003e within 6 h under one solar irradiation, which was almost the same as that in pure water. In addition, when the brine salinity was increased to 10%, the evaporation rate was reduced to 1.96 kg m\u003csup\u003e-2\u003c/sup\u003e h\u003csup\u003e-1\u003c/sup\u003e, but the performance remained stable during the long evaporation process (\u003cstrong\u003eFig. S26\u003c/strong\u003e). However, when the salinity exceeded 20%, salt crystallization occurred at the evaporation interface of E-150, causing the evaporation rate to continue decreasing. These results showed that E-150 had an acceptable resistance to salt crystallization, which was suitable for all seawaters in the world, and some high-salinity brines from industry (≤10%). The salt resistance of E-150 was mainly due to the partial retention of lignin in the woody biomass framework, which made the interconnected multistage channel structure intact. As shown in \u003cstrong\u003eFig. 5b\u003c/strong\u003e,\u0026nbsp;these multistage channels provided low-tortuosity pathways with different hydraulic conductivities. When the desalination was carried out, the water flux in the small-diameter channel was smaller than that in the large-diameter channel, resulting in a larger salt concentration in the small-diameter channel.\u0026nbsp;The resulting in-plane concentration gradient encouraged salt ions to shuttle transversally through the ray cell.\u0026nbsp;Simultaneously, salt ions accumulated inside the large-diameter channels diffused back into the seawater.\u0026nbsp;This multidirectional mass transfer characteristic not only endowed E-150 with anti-salt crystallization properties, but also enabled the salt crystals on the evaporator surface to be efficiently eliminated under dark conditions (\u003cstrong\u003eFig. S27\u003c/strong\u003e).\u0026nbsp;The efficient elimination of salt crystals under dark conditions could further broaden the practical application scenarios of E-150 through the day-night cycle.\u003c/p\u003e\u003cp\u003eTo verify the application of E-150 under the actual sun (\u003cstrong\u003eFig. 5c\u003c/strong\u003e), an outdoor evaporation test was conducted in actual seawater from the Bohai Sea (approximately 40° N and 121° E) on September 20, 2024 in Beijing, China (8:00-17:00). During the evaporation test, the water vapor is condensed in the cooling area to avoid the effect of light occlusion and light refraction by the condensation water at the top (\u003cstrong\u003eFig. S28\u003c/strong\u003e). As shown in \u003cstrong\u003eFig. 5d\u003c/strong\u003e, the evaporation rate of E-150 gradually increased in the initial stage, and stabilized at about 2.00 kg m\u003csup\u003e-2\u003c/sup\u003e h\u003csup\u003e-1\u003c/sup\u003e from 11:00 to 14:00, demonstrating the practical application potential of E-150. It is worth noting that the lower evaporation rate in practical applications is due to the weaker solar flux in Beijing during autumn. The long-term stability and cycling performance of E-150 were investigated using actual seawater. As shown in \u003cstrong\u003eFig. 5e\u003c/strong\u003e, E-150 was continuously evaporated in seawater for 12 h under one solar irradiation, showing a stable evaporation rate of 2.16 kg m\u003csup\u003e-2\u003c/sup\u003e h\u003csup\u003e-1\u003c/sup\u003e, and almost no salt crystallization was observed.\u0026nbsp;Moreover, during 10 consecutive 4 h evaporation tests, the evaporation rate of E-150 still remained stable (\u003cstrong\u003eFig. 5g\u003c/strong\u003e), demonstrating excellent long-term stability. Furthermore, the E-A and E-150 used in seawater were air-dried at room temperature, and their recyclability was compared. As shown in \u003cstrong\u003eFigs. 5f and S29\u003c/strong\u003e, there was almost no change in E-150 after recovery, while the volume of E-A was sharply reduced after recovery, and the surface carbon layer was seriously damaged.\u0026nbsp;The excellent recyclability of E-150 was attributed to the rigidity provided by the partially retained lignin (\u003cstrong\u003eFig. S30\u003c/strong\u003e).\u0026nbsp;In contrast, E-A\u0026nbsp;lacking lignin not only could not be recycled, but also was prone to surface collapse during the process of lignin solution coating (\u003cstrong\u003eFig. S31\u003c/strong\u003e).\u0026nbsp;Furthermore, due to the higher proportion of intermediate water with weak hydrogen-bonding characteristics in E-150, the binding energy between this water and contaminant particles is smaller. Thus, E-150 exhibits enhanced purification capacity (\u003cstrong\u003eFig. S32\u003c/strong\u003e).\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis work demonstrates a compositional and structural reconstitution strategy of a woody biomass framework that enables simultaneous optimization of water transport and photothermal conversion in solar evaporators. Combining theoretical simulations with experimental validation, this study reveals that partially retained lignin facilitates the formation of intermediate water through both functional group interactions and microscopic spatial conditions, thereby reducing the evaporation enthalpy while ensuring effective water pumping to the evaporation interface. Simultaneously, the photothermal conversion layer prepared by laser etching of lignin combined the advantages of graphene and graphite carbon while exhibiting an ordered multistage pore structure, which had excellent light absorption capacity, photothermal conversion efficiency and promoted the formation of microdroplets with low enthalpy of evaporation. Under one-sun illumination, the evaporator E-150 achieves a high evaporation rate of 2.24 kg m⁻\u0026sup2; h⁻\u0026sup1; and a photothermal conversion efficiency of 91.52%, outperforming most previously reported woody biomass-based solar evaporators. Additionally, the appropriate lignin content in the woody biomass framework provided a solid guarantee for the evaporator's anti-salt crystallization performance, recovery, and purification performance. The reconstituted woody framework strategy proposed in this work offers a simple, low-energy, and cost-effective method with substantial potential for large-scale application, providing a promising model for the sustainable development of woody biomass-based solar evaporators, balancing both economic and environmental benefits.\u003c/p\u003e"},{"header":"Experimental Section","content":"\u003cp\u003e\u003cstrong\u003eMaterials:\u0026nbsp;\u003c/strong\u003eThe chemical composition of balsa wood from Fujian Province, China, is shown in Table S1, and the size of the sample used in this study was 10*10*5 mm. Aluminum chloride hexahydrate (97.0%), sodium hypochlorite pentahydrate (\u0026ge;39%), sodium alginate (AR), sodium hydroxide (96%), ethanol (99.7%), methylene blue (\u0026ge;70.0%), and direct red 80 (\u0026ge;25%) were purchased from Aladdin Co., Ltd. Other reagents were analytical grade and purchased from Macklin Co., Ltd. The actual seawater was taken from China\u0026apos;s Bohai Sea (approximately 40\u0026deg; N and 121\u0026deg; E) in October 2023, which was not further treated before use.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePretreatment in alcohol solution system:\u003c/strong\u003e Before pretreatment, the balsa wood blocks were immersed in a reaction mixture, ethanol-water solution (1:1), with 0.02 mol/L aluminum chloride for 2 days. The soaked balsa wood blocks and the reaction mixture were added into a polytetrafluoroethylene-lined reactor for delignification pretreatment for 3 h, and the effect of pretreatment temperature (140-170 \u0026deg;C) was studied in detail. After the pretreatment, the wood blocks were taken out and immersed in a 50% ethanol aqueous solution to replace the solution containing lignin, and this step was repeated twice. Finally, the wood blocks were immersed in deionized water to displace the ethanol and freeze-dried to obtain a woody biomass framework (W-140 to W-170). For the pretreatment liquid, ethanol was recovered by vacuum rotary evaporation, and lignin was obtained by centrifuging for subsequent laser etching. It was worth noting that all chemicals used in this section were easily recyclable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn addition, as a control sample, wood was completely lignin-removed by the traditional sodium chlorite process to obtain woody biomass framework W-A, and the lignin in this process could not be recovered.\u0026nbsp;Specific operations were described in the Supporting Information.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLaser etching:\u003c/strong\u003e To better contrast, the lignin used for laser etching was the lignin recovered from the above pretreatment temperature of 160 \u003csup\u003eo\u003c/sup\u003eC.\u0026nbsp;0.5 g lignin and 0.2 g sodium alginate were dissolved in 10 mL of 0.1 M sodium hydroxide solution, then 0.3 mL solution was evenly coated on the surface of a woody biomass framework and air-dried.\u0026nbsp;Subsequently, 0.3 mL of the solution was evenly coated on the surface of the\u0026nbsp;woody biomass framework\u0026nbsp;and air-dried.\u0026nbsp;Finally, a series of woody biomass-based solar evaporators were obtained by laser etching using a semiconductor laser engraving machine with a peak laser power of 7.0 W.\u0026nbsp;Except for the samples that investigated the effect of laser power, the laser power used in the etching process of the other samples was 45%, and the scanning rate was 70 mm/s.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterial Characterization:\u0026nbsp;\u003c/strong\u003eAfter the woody biomass framework was crushed, its chemical composition was determined using the previously reported method.\u003csup\u003e50\u003c/sup\u003e The morphologies and energy-dispersed X-ray spectroscopy (EDS) were observed by scanning electron microscope (SEM, Hitachi Regulus8100, Japan) and high-resolution transmission electron microscopy (HRTEM, JEM-2100, Japan). Raman spectra of graphitization layers and water in woody biomass frameworks were detected by Raman microscopy (X-plor, France). Surface wettability was determined by an OCA20 Contact angle measurement system (Data-physics, Germany). The light absorption capacity of the evaporator was recorded by UV\u0026ndash;visible-NIR spectrophotometer (UV3600, Shimadzu, Japan). The evaporation enthalpies of water in the woody biomass framework were determined by a differential scanning calorimeter (DSC-60 Plus, Shimadzu, Japan) and a dark evaporation experiment, respectively. The compressive strength of wood was measured by a universal testing machine (UTM6530, China). The type of water in the woody biomass framework was characterized by low-field nuclear magnetic resonance (1D/2D LFNMR, VTM20-010V-I, China).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSolar Evaporation Experiment:\u0026nbsp;\u003c/strong\u003eA 300 W xenon lamp (PLS-SXE3000, China) with an AM 1.5G filter was used to simulate sunlight, and a densitometer (CELNP2000-2(10)A, China) was used to adjust the radiation intensity at the evaporation interface to one sunlight (about 1 kW m\u003csup\u003e-2\u003c/sup\u003e).\u0026nbsp;The surface temperature of the woody biomass-based evaporator and water temperature were recorded with an infrared thermal imager (FLIR-E4, USA).\u0026nbsp;Mass changes during evaporation were measured using an electronic balance (BSM-220.4, China) with an accuracy of 0.0001 g.\u0026nbsp;The evaporation rate (v) was calculated in equation (1) as follows:\u003c/p\u003e\n\u003cp\u003ev=\u0026Delta;m/s*\u0026Delta;t \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;(1)\u003c/p\u003e\n\u003cp\u003eWhere \u0026Delta;m was the overall mass change, s was the area at the top of the evaporator, and \u0026Delta;t was the irradiation time change.\u003c/p\u003e\n\u003cp\u003eThe photothermal conversion efficiency (\u003cem\u003e\u0026eta;\u003c/em\u003e) of the evaporator was calculated by equation (2) as follows:\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u0026eta;\u003c/em\u003e=v*H\u003csub\u003eE\u003c/sub\u003e/(C\u003csub\u003eopt\u003c/sub\u003e*P\u003csub\u003ei\u003c/sub\u003e) \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;(2)\u003c/p\u003e\n\u003cp\u003eWhere \u0026nu; was the evaporation rate at a steady state, H\u003csub\u003eE\u003c/sub\u003e was the evaporation enthalpy of water in the corresponding sample, C\u003csub\u003eopt\u003c/sub\u003e was the light absorption coefficient of the evaporator surface as shown in \u003cstrong\u003eFig. 3g\u003c/strong\u003e, and P\u003csub\u003ei\u003c/sub\u003e was the radiant power of one sun (1 kW m\u003csup\u003e-2\u003c/sup\u003e).\u003c/p\u003e\n\u003cp\u003eIn addition, the water vapour generated by the evaporator was collected by a self-made device (\u003cstrong\u003eFig. 5c and S21\u003c/strong\u003e) to measure the purification capacity of the evaporator. An inductively coupled plasma source mass spectrometer (ICP-MS, Agilent 7800ce, USA) was used to measure the concentration of metal ions in water, while the concentration of dyes in water was measured by an ultraviolet spectrophotometer (UV-2450, Japan).\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the National Natural Science Foundation of China (22308029), the Knowledge Innovation Program of Wuhan-Basi Research (2023020201010072), the Fundamental Research Funds for the Central Universities (691000003), and the 5\u0026middot;5 Engineering Research \u0026amp; Innovation Team Project of Beijing Forestry University (No. BLRC 2023B05). Additionally, the authors appreciate the assistance of the Innovation Platform for High-Value Utilization of Forest Resources at Beijing Forestry University.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eT.Y., C.C., X.S. and B.W.\u0026nbsp;conceived the concept, processing, and structure details. B.W., Y.H. and Z.Y. performed the design and preparation of the evaporator. B.W. and Y.H. carried out the evaporation test. B.W., Z.Y., and Y.H. co-wrote the manuscript. T.Y., C.C. and X.S.\u0026nbsp;supervised the work and revised the manuscript. J.L.W.\u0026nbsp;provided guidance on the structural analysis of lignocellulose.\u0026nbsp;Q.S. provided assistance in the enthalpy of the evaporation test of water.\u0026nbsp;J.M.W. and X.Z. participated in large-scale sample preparation and outdoor evaporation tests. All authors commented on the submitted version of the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eShannon, M. A. et al. Science and technology for water purification in the coming decades. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e452\u003c/strong\u003e, 301-310 (2008).\u003c/li\u003e\n\u003cli\u003eKim, Y. \u0026amp; Lee, W.-g. Seawater and its resources. In: \u003cem\u003eSeawater batteries: principles, materials and technology\u003c/em\u003e). Springer, 1-35 (2022).\u003c/li\u003e\n\u003cli\u003eChaule, S. et al. Rational design of a high performance and robust solar evaporator via 3D‐printing technology. \u003cem\u003eAdv. Mater.\u003c/em\u003e \u003cstrong\u003e33\u003c/strong\u003e, 2102649 (2021).\u003c/li\u003e\n\u003cli\u003eChen, C., Kuang, Y. \u0026amp; Hu, L. Challenges and opportunities for solar evaporation. \u003cem\u003eJoule\u003c/em\u003e \u003cstrong\u003e3\u003c/strong\u003e, 683-718 (2019).\u003c/li\u003e\n\u003cli\u003eTao, P. et al. Solar-driven interfacial evaporation. \u003cem\u003eNat. Energy\u003c/em\u003e \u003cstrong\u003e3\u003c/strong\u003e, 1031-1041 (2018).\u003c/li\u003e\n\u003cli\u003eWu, X. et al. Interfacial solar evaporation: from fundamental research to applications. \u003cem\u003eAdv. Mater.\u003c/em\u003e, 2313090 (2024).\u003c/li\u003e\n\u003cli\u003eHe, S. et al. Nature-inspired salt resistant bimodal porous solar evaporator for efficient and stable water desalination. \u003cem\u003eEnergy Environ. Sci.\u003c/em\u003e \u003cstrong\u003e12\u003c/strong\u003e, 1558-1567 (2019).\u003c/li\u003e\n\u003cli\u003eChen, L. et al. 3D-printed tripodal porous wood-mimetic cellulosic composite evaporator for salt-free water desalination. \u003cem\u003eCompos. Part. B-Eng.\u003c/em\u003e \u003cstrong\u003e263\u003c/strong\u003e, 110830 (2023).\u003c/li\u003e\n\u003cli\u003eChao, W. et al. Enhanced wood-derived photothermal evaporation system by in-situ incorporated lignin carbon quantum dots. \u003cem\u003eChem. Eng. J.\u003c/em\u003e \u003cstrong\u003e405\u003c/strong\u003e, 126703 (2021).\u003c/li\u003e\n\u003cli\u003eXu, N. et al. Flatband \u0026lambda;-Ti\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e boosts solar evaporation. \u003cem\u003eJoule\u003c/em\u003e \u003cstrong\u003e7\u003c/strong\u003e, 2665-2667 (2023).\u003c/li\u003e\n\u003cli\u003eLi, L. et al. Polyelectrolyte hydrogel‐functionalized photothermal sponge enables simultaneously continuous solar desalination and electricity generation without salt accumulation. \u003cem\u003eAdv. Mater.\u003c/em\u003e, 2401171 (2024).\u003c/li\u003e\n\u003cli\u003eZhao, F. et al. Highly efficient solar vapour generation via hierarchically nanostructured gels. \u003cem\u003eNat. nanot.\u003c/em\u003e \u003cstrong\u003e13\u003c/strong\u003e, 489-495 (2018).\u003c/li\u003e\n\u003cli\u003eMa, X. et al. Wood-based solar-driven interfacial evaporators: Design and application. \u003cem\u003eChem. Eng. J.\u003c/em\u003e, 144517 (2023).\u003c/li\u003e\n\u003cli\u003eChen, L. et al. Biomass waste-assisted micro (nano) plastics capture, utilization, and storage for sustainable water remediation. \u003cem\u003eThe Innovation\u003c/em\u003e \u003cstrong\u003e5\u003c/strong\u003e, 100655 (2024).\u003c/li\u003e\n\u003cli\u003ePetridis, L. \u0026amp; Smith, J. C. Molecular-level driving forces in lignocellulosic biomass deconstruction for bioenergy. \u003cem\u003eNat. Rev. Chem.\u003c/em\u003e \u003cstrong\u003e2\u003c/strong\u003e, 382-389 (2018).\u003c/li\u003e\n\u003cli\u003eThybring, E. et al. Water in wood: a review of current understanding and knowledge gaps. Forests \u003cstrong\u003e13\u003c/strong\u003e, 2051 (2022).\u003c/li\u003e\n\u003cli\u003eDong, Y. et al. Reviewing wood-based solar-driven interfacial evaporators for desalination. \u003cem\u003eWater Res.\u003c/em\u003e \u003cstrong\u003e223\u003c/strong\u003e, 119011 (2022).\u003c/li\u003e\n\u003cli\u003eGnanasekaran, A. \u0026amp; Rajaram, K. Flake-like CuO nanostructure coated on flame treated eucalyptus wood evaporator for efficient solar steam generation at outdoor conditions. \u003cem\u003eColloid. Surface. A.\u003c/em\u003e \u003cstrong\u003e662\u003c/strong\u003e, 130975 (2023).\u003c/li\u003e\n\u003cli\u003eWu, W. et al. Cellulose‐based interfacial solar evaporators: structural regulation and performance manipulation. \u003cem\u003eAdv. Funct. Mater.\u003c/em\u003e \u003cstrong\u003e33\u003c/strong\u003e, 2302351 (2023).\u003c/li\u003e\n\u003cli\u003eLi, X. P. et al. Reshapable MXene/graphene oxide/polyaniline plastic hybrids with patternable surfaces for highly efficient solar‐driven water purification. \u003cem\u003eAdv. Funct. Mater.\u003c/em\u003e \u003cstrong\u003e32\u003c/strong\u003e, 2110636 (2022).\u003c/li\u003e\n\u003cli\u003eWang, B. et al. Harnessing renewable lignocellulosic potential for sustainable wastewater purification. \u003cem\u003eResearch\u003c/em\u003e \u003cstrong\u003e7\u003c/strong\u003e, 0347 (2024).\u003c/li\u003e\n\u003cli\u003eTran, C. D. et al. Sustainable energy‐storage materials from lignin\u0026ndash;graphene nanocomposite‐derived porous carbon film. \u003cem\u003eEnergy Technol.\u003c/em\u003e \u003cstrong\u003e5\u003c/strong\u003e, 1927-1935 (2017).\u003c/li\u003e\n\u003cli\u003eOkamoto, S. et al. Additive effect of graphene and lignin‐derived graphene on radical polymerization behaviors of methacrylate monomers. \u003cem\u003eMacromol. Chem. Phys.\u003c/em\u003e \u003cstrong\u003e224\u003c/strong\u003e, 2300276 (2023).\u003c/li\u003e\n\u003cli\u003eLin, J. et al. Laser-induced porous graphene films from commercial polymers. \u003cem\u003eNat. Commun.\u003c/em\u003e \u003cstrong\u003e5\u003c/strong\u003e, 5714 (2014).\u003c/li\u003e\n\u003cli\u003eYang, Z. et al. One-step sustainable preparation of laser induced S-doped graphene for assembly of high-performance supercapacitors. \u003cem\u003eJ. Clean. Prod.\u003c/em\u003e \u003cstrong\u003e450\u003c/strong\u003e, 141956 (2024).\u003c/li\u003e\n\u003cli\u003eGu, Y. et al. Solar‐powered high‐performance lignin‐wood evaporator for solar steam generation. \u003cem\u003eAdv. Funct. Mater.\u003c/em\u003e \u003cstrong\u003e33\u003c/strong\u003e, 2306947 (2023).\u003c/li\u003e\n\u003cli\u003eZhao, F. et al. Materials for solar-powered water evaporation. \u003cem\u003eNat. Rev. Mater.\u003c/em\u003e \u003cstrong\u003e5\u003c/strong\u003e, 388-401 (2020).\u003c/li\u003e\n\u003cli\u003eWei, D. et al. Water activation in solar‐powered vapor generation. \u003cem\u003eAdv. Mater.\u003c/em\u003e \u003cstrong\u003e35\u003c/strong\u003e, 2212100 (2023).\u003c/li\u003e\n\u003cli\u003eGnanasekaran, A. \u0026amp; Rajaram, K. Rational design of different interfacial evaporators for solar steam generation: Recent development, fabrication, challenges and applications. \u003cem\u003eRenew. Sust. Energ. Rev.\u003c/em\u003e \u003cstrong\u003e192\u003c/strong\u003e, 114202 (2024).\u003c/li\u003e\n\u003cli\u003eZeng, Y. et al. Lignin plays a negative role in the biochemical process for producing lignocellulosic biofuels. \u003cem\u003eCurr. Opin. Biotechnol.\u003c/em\u003e \u003cstrong\u003e27\u003c/strong\u003e, 38-45 (2014).\u003c/li\u003e\n\u003cli\u003eGiummarella, N. et al. A critical review on the analysis of lignin carbohydrate bonds. \u003cem\u003eGreen Chem.\u003c/em\u003e \u003cstrong\u003e21\u003c/strong\u003e, 1573-1595 (2019).\u003c/li\u003e\n\u003cli\u003eWang, J. et al. Atomic force microscopy and molecular dynamics simulations for study of lignin solution self‐assembly mechanisms in organic\u0026ndash;aqueous solvent mixtures. \u003cem\u003eChemSusChem\u003c/em\u003e \u003cstrong\u003e13\u003c/strong\u003e, 4420-4427 (2020).\u003c/li\u003e\n\u003cli\u003eHackenstrass, K., Hasani, M. \u0026amp; Wohlert, M. Structure, flexibility and hydration properties of lignin dimers studied with Molecular Dynamics simulations. \u003cem\u003eHolzforschung\u003c/em\u003e \u003cstrong\u003e78\u003c/strong\u003e, 98-108 (2024).\u003c/li\u003e\n\u003cli\u003eXuemin, G., Peng, Y. \u0026amp; Yanfen, W. How to reduce enthalpy in the interfacial solar water generation system for enhancing efficiency? \u003cem\u003eNano Ener.\u003c/em\u003e, 109434 (2024).\u003c/li\u003e\n\u003cli\u003eJing, S. et al. The critical roles of water in the processing, structure, and properties of nanocellulose. \u003cem\u003eACS nano\u003c/em\u003e \u003cstrong\u003e17\u003c/strong\u003e, 22196-22226 (2023).\u003c/li\u003e\n\u003cli\u003eJia, L. et al. Crystal plane engineering to boost water cluster evaporation for enhanced solar steam generation. \u003cem\u003eNano Lett.\u003c/em\u003e \u003cstrong\u003e24\u003c/strong\u003e, 1753-1760 (2024).\u003c/li\u003e\n\u003cli\u003eEngelund, E. T. et al. A critical discussion of the physics of wood\u0026ndash;water interactions. \u003cem\u003eWood. Sci. Technol.\u003c/em\u003e \u003cstrong\u003e47\u003c/strong\u003e, 141-161 (2013).\u003c/li\u003e\n\u003cli\u003eBonnet, M. et al. NMR determination of sorption isotherms in earlywood and latewood of Douglas fir. Identification of bound water components related to their local environment. \u003cem\u003eHolzforschung\u003c/em\u003e \u003cstrong\u003e71\u003c/strong\u003e, 481-490 (2017).\u003c/li\u003e\n\u003cli\u003eLi, J. \u0026amp; Ma, E. Characterization of water in wood by time-domain nuclear magnetic resonance spectroscopy (TD-NMR): a review. \u003cem\u003eForests\u003c/em\u003e \u003cstrong\u003e12\u003c/strong\u003e, 886 (2021).\u003c/li\u003e\n\u003cli\u003eKuang, Y. et al. A high‐performance self‐regenerating solar evaporator for continuous water desalination. \u003cem\u003eAdv. Mater.\u003c/em\u003e \u003cstrong\u003e31\u003c/strong\u003e, 1900498 (2019).\u003c/li\u003e\n\u003cli\u003eZhang, W. et al. Lignin laser lithography: a direct‐write method for fabricating 3D graphene electrodes for microsupercapacitors. \u003cem\u003eAdv. Energy Mater.\u003c/em\u003e \u003cstrong\u003e8\u003c/strong\u003e, 1801840 (2018).\u003c/li\u003e\n\u003cli\u003eZhang, C. et al. An integrated and robust plant pulse monitoring system based on biomimetic wearable sensor. \u003cem\u003enpj Flex. Electron.\u003c/em\u003e \u003cstrong\u003e6\u003c/strong\u003e, 43 (2022).\u003c/li\u003e\n\u003cli\u003eWu, J.-B. et al. Raman spectroscopy of graphene-based materials and its applications in related devices. \u003cem\u003eChem. Soc. Rev.\u003c/em\u003e \u003cstrong\u003e47\u003c/strong\u003e, 1822-1873 (2018).\u003c/li\u003e\n\u003cli\u003eXie, Z. et al. The rise of 2D photothermal materials beyond graphene for clean water production. \u003cem\u003eAdv. Sci.\u003c/em\u003e \u003cstrong\u003e7\u003c/strong\u003e, 1902236 (2020).\u003c/li\u003e\n\u003cli\u003eMohan, V. B. et al. Graphene-based materials and their composites: A review on production, applications and product limitations. \u003cem\u003eCompos. Part. B-Eng.\u003c/em\u003e \u003cstrong\u003e142\u003c/strong\u003e, 200-220 (2018).\u003c/li\u003e\n\u003cli\u003eYang, Z. et al. A solely biobased strain sensor with an ultra-precision response via a surface graphitization strategy. \u003cem\u003eJ. Mater. Chem. A\u003c/em\u003e \u003cstrong\u003e11\u003c/strong\u003e, 24928-24938 (2023).\u003c/li\u003e\n\u003cli\u003ePang, B. et al. Molecular‐scale design of cellulose‐based functional materials for flexible electronic devices. \u003cem\u003eAdv. Electron. Mater.\u003c/em\u003e \u003cstrong\u003e7\u003c/strong\u003e, 2000944 (2021).\u003c/li\u003e\n\u003cli\u003eDu, C. et al. Heat-localized solar evaporation: Transport processes and applications. \u003cem\u003eNano Ener.\u003c/em\u003e \u003cstrong\u003e107\u003c/strong\u003e, 108086 (2023).\u003c/li\u003e\n\u003cli\u003eLin, X. et al. Fully lignocellulosic biomass‐based double‐layered porous hydrogel for efficient solar steam generation. \u003cem\u003eAdv. Funct. Mater.\u003c/em\u003e \u003cstrong\u003e32\u003c/strong\u003e, 2209262 (2022).\u003c/li\u003e\n\u003cli\u003eSluiter, A. et al. Determination of structural carbohydrates and lignin in biomass. \u003cem\u003eLaboratory analytical procedure\u003c/em\u003e \u003cstrong\u003e1617\u003c/strong\u003e, 1-16 (2008).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Woody biomass, Lignin, Lignocellulose, Solar desalination, Salt resistance","lastPublishedDoi":"10.21203/rs.3.rs-7392399/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7392399/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSolar-driven interfacial evaporation is a promising solution to address global freshwater scarcity, with woody biomass-based evaporators standing out for their sustainability and cost-effectiveness. However, current woody biomass-based systems often suffer from inefficient water management and suboptimal photothermal performance. Herein, we develop a dual-function lignin-engineered reconstituted wood framework strategy, achieving both compositional and structural optimization of woody biomass to enhance its evaporation performance via superior water management and thermal management. By partially retaining and reconfiguring lignin within the woody biomass framework, a higher fraction of loosely bound “intermediate water” with reduced evaporation enthalpy is generated while preserving the water-pumping capability. Concurrently, the extracted lignin is upcycled via laser-induced graphitization into a broadband photothermal layer composed of hierarchical graphene/graphitic carbon structures with solar absorptivity exceeding 95%. This synergistic design results in the E-150 solar evaporator, which achieves an evaporation rate of 2.24 kg m⁻² h⁻¹ and a photothermal conversion efficiency of 91.52% under one-sun irradiation, surpassing most reported wood-based evaporators. Moreover, the retained lignin sustains multiscale channel integrity, imparting strong salt resistance, high recyclability, and robust purification capabilities. This integrated biomass valorization strategy provides a scalable, low-cost, and eco-friendly route for high-performance solar desalination and sustainable water-energy applications.\u003c/p\u003e","manuscriptTitle":"Compositional and Structural Reconstitution of Woody Biomass Framework via Dual-Functional Lignin Engineering Toward Efficient and Salt-Resistant Solar Desalination","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-04 08:06:51","doi":"10.21203/rs.3.rs-7392399/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"5edce3df-870d-4d6d-892d-c6d8d6a2ab42","owner":[],"postedDate":"September 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":54089314,"name":"Physical sciences/Chemistry/Green chemistry/Sustainability"},{"id":54089315,"name":"Physical sciences/Energy science and technology/Renewable energy/Solar energy/Solar thermal energy"},{"id":54089316,"name":"Scientific community and society/Water resources"}],"tags":[],"updatedAt":"2026-04-24T07:08:17+00:00","versionOfRecord":{"articleIdentity":"rs-7392399","link":"https://doi.org/10.1038/s41467-026-70270-0","journal":{"identity":"nature-communications","isVorOnly":false,"title":"Nature Communications"},"publishedOn":"2026-03-10 04:00:00","publishedOnDateReadable":"March 10th, 2026"},"versionCreatedAt":"2025-09-04 08:06:51","video":"","vorDoi":"10.1038/s41467-026-70270-0","vorDoiUrl":"https://doi.org/10.1038/s41467-026-70270-0","workflowStages":[]},"version":"v1","identity":"rs-7392399","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7392399","identity":"rs-7392399","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}