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![Schematic showing cellulose fiber from molecular to macromolecular level, the corresponding physiochemical properties favoring solar steam generation and various cellulose‐based solar evaporators utilizing BNC, wood, CNF, air‐laid paper, cellulose paper, and cotton fabric. Central image of cellulose nanomaterials: Reproduced with permission.[qv: [24]] Copyright 2013, American Chemical Society. Top‐left image of bacterial nanocellulose: Reproduced with permission.[qv: [8b]] Copyright 2016, Wiley‐VCH. Top‐right image of wood: Reproduced with permission.[qv: [4]] Copyright 2019, Cell Press. Rightmost image of a CNF: Reproduced with permission.[qv: [20]] Copyright 2018, American Chemical Society. Bottom‐right image of cellulose paper: Reproduced with permission.[qv: [25]] Copyright 2018, American Chemical Society. Bottom‐left image of air‐laid paper: Reproduced with permission.[qv: [26]] Copyright 2018, Wiley‐VCH. Leftmost image of cotton fabric: Reproduced with permission.[qv: [27]] Copyright 2018, American Chemical Society.](profile/Sisi-Cao/publication/342172866/figure/fig1/AS:11431281173336360@1688836765471/Schematic-showing-cellulose-fiber-from-molecular-to-macromolecular-level-the.png)
Schematic showing cellulose fiber from molecular to macromolecular level, the corresponding physiochemical properties favoring solar steam generation and various cellulose‐based solar evaporators utilizing BNC, wood, CNF, air‐laid paper, cellulose paper, and cotton fabric. Central image of cellulose nanomaterials: Reproduced with permission.[qv: [24]] Copyright 2013, American Chemical Society. Top‐left image of bacterial nanocellulose: Reproduced with permission.[qv: [8b]] Copyright 2016, Wiley‐VCH. Top‐right image of wood: Reproduced with permission.[qv: [4]] Copyright 2019, Cell Press. Rightmost image of a CNF: Reproduced with permission.[qv: [20]] Copyright 2018, American Chemical Society. Bottom‐right image of cellulose paper: Reproduced with permission.[qv: [25]] Copyright 2018, American Chemical Society. Bottom‐left image of air‐laid paper: Reproduced with permission.[qv: [26]] Copyright 2018, Wiley‐VCH. Leftmost image of cotton fabric: Reproduced with permission.[qv: [27]] Copyright 2018, American Chemical Society.
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Herein, the recent advances in realizing highly efficient cellulose‐based solar evaporators for alleviating the global water crisis are summarized. Fresh water scarcity is one of the most threatening issues for sustainable development. Solar steam generation, which harnesses the abundant sunlight, has been recognized as a sustainable approach to ha...
Citations
... Solar interfacial steam generation (SISG) represents a promising technology harnessing renewable solar energy to produce clean water from sources such as brine and seawater. [1][2][3][4][5][6] The efficiency of SISG is primarily characterized by its water evaporation rate. [7,8] Materials, such as wood, [9][10][11] foam, [12,13] and hydrogel, [7,14,15] are commonly employed to design 2D flat solar evaporators. ...
... Under solar radiation of 1 kW m −2 without wind, the diffuse radiation energy (q diffuse ) obtained by the KAC-coated wood evaporator at various heights (4,12,15,18, and 32 cm) are 0.055, 0.234, 0.283, 0.420, and 0.241 W (Table S2, Supporting Information), respectively. Notably, these values are 0.50, 2.34, 2.83, 4.20, and 2.41 times those of the obtained direct solar radiation energy (q solar , 0.1 W), indicating efficient solar energy absorption by the evaporator with increased exposed evaporated area. ...
The water evaporation rate of 3D solar evaporator heavily relies on the water transport height of the evaporator. In this work, a 3D solar evaporator featuring a soil capillary‐like structure is designed by surface coating native balsa wood using potassium hydroxide activated carbon (KAC). This KAC‐coated wood evaporator can transport water up to 32 cm, surpassing that of native wood by ≈8 times. Moreover, under 1 kW m⁻² solar radiation without wind, the KAC‐coated wood evaporator exhibits a remarkable water evaporation rate of 25.3 kg m⁻² h⁻¹, ranking among the highest compared with other reported evaporators. The exceptional water transport capabilities of the KAC‐coated wood should be attributed to the black and hydrophilic KAC film, which creates a porous network resembling a soil capillary structure to facilitate efficient water transport. In the porous network of coated KAC film, the small internal pores play a pivotal role in achieving rapid capillary condensation, while the larger interstitial channels store condensed water, further promoting water transport up more and micropore capillary condensation. Moreover, this innovative design demonstrates efficacy in retarding phenol from wastewater through absorption onto the coated KAC film, thus presenting a new avenue for high‐efficiency clean water production.
... To achieve enhanced solar evaporation efficiency, the light absorber should demonstrate broad-spectrum light absorption for optimal conversion of photons into thermal energy [27]. Simultaneously, the supporting substrate ought to possess low thermal conductivity to minimize heat dissipation and facilitate efficient water transport through capillary action [28]. Wood, with its hierarchical structures and excellent thermal insulation properties, presents itself as a promising and sustainable material for solar steam generation [12]. ...
Harnessing and effectively utilizing abundant and sustainable solar energy is regarded as a promising solution to the global energy crisis. Forests, being nature’s largest light energy capturing units, bestow oxygen and shelter upon all living beings, making them an invaluable gift to humanity. Apart from serving as natural air ionizers, load-bearing structures, and traditional building materials, wood and its derivatives can also be employed in cutting-edge sustainable applications. Their manifold advantages encompass a naturally porous and hierarchical structure for efficient water and nutrient transport, low thermal conductivity, mechanical stability, as well as versatile chemistry achieved through structural engineering and chemical or thermal modifications. This review provides an overview of the synergistic optical and thermal applications of wood for seawater desalination, wastewater treatment, and light management in energy-efficient buildings. The emphasis lies on elucidating the structure and application properties of wood with respect to establishing a symbiotic relationship between solar energy and wood towards sustainability.
... It is a potential alternative to conventional plastics because of its remarkable intrinsic chemical and biological characteristics Dubey et al. 2018). Owing to its biodegradability, it has attracted significant attention (Cao et al. 2021;Sannino et al. 2009). Therefore, cellulose can be decomposed by current wastewater treatment systems to prevent its accumulation in aquatic ecosystems (Ghasemlou et al. 2022;Pérez et al. 2022). ...
Microplastics including microbeads that are heavily utilized in our daily necessities such as cleaners, toothpastes, and cosmetic products as well as in industrial applications have become a severe environmental issue because of their non-degradable characteristics. Upon accumulation in aquatic organisms, microplastics eventually enter the human food supply chain, where these are possibly hazardous to humans. Herein, we demonstrate the fabrication of microbeads comprising abundant, sustainable, and biodegradable cellulose through an electrospray-based process of cellulose acetate and subsequent chemical treatment as a sustainable alternative to microplastic particles, which are widely used in a range of consumer products in our daily lives. We further show that inferior mechanical properties, which degrade the potential of cellulose, can be improved dramatically by incorporating triazine-based covalent organic nanosheets (CONs). The compressive strength of composite microbeads at breakage is measured to be 238 ± 18 MPa, which is higher than those of cellulose microbeads without CON (142 ± 22 MPa) and polypropylene microbeads (199 ± 6 MPa). The study proposes a simple albeit effective approach to fabricating cellulose microbeads with enhanced mechanical properties. Thereby, it provides insights into the replacement of petroleum-based microplastics with an environmentally friendly material system.
Graphical abstract
... Evaporation-driven generation technology, in particular, leverages water, which covers more than 70% of the Earth's surface and is universally available, offering relatively fewer time and space restrictions than other generation methods [9][10][11][12][13][14][15][16]. In addition, other research organizations are also investigating various materials for generator materials, which is expected to lower the cost of generator production in the future [17][18][19][20][21][22][23][24][25][26]. ...
Power generation technologies based on water movement and evaporation use water, which covers more than 70% of the Earth’s surface and can also generate power from moisture in the air. Studies are conducted to diversify materials to increase power generation performance and validate energy generation mechanisms. In this study, a water-based generator was fabricated by coating cellulose acetate with carbon black. To optimize the generator, Fourier-transform infrared spectroscopy, specific surface area, zeta potential, particle size, and electrical performance analyses were conducted. The developed generator is a cylindrical generator with a diameter of 7.5 mm and length of 20 mm, which can generate a voltage of 0.15 V and current of 82 μA. Additionally, we analyzed the power generation performance using three factors (physical properties, cation effect, and evaporation environment) and proposed an energy generation mechanism. Furthermore, we developed an eco-friendly and low-cost generator using natural fibers with a simple manufacturing process. The proposed generator can contribute to the identification of energy generation mechanisms and is expected to be used as an alternative energy source in the future.
... Water transport through nanocapillaries, such as in biological systems and nanoscale materials, is ubiquitous in the natural world and has many applications in technology [1][2][3][4][5][6][7][8]. In biological systems, capillary action in nano capillaries enables efficient water transport in plants, allowing them to absorb water from the soil and distribute it throughout their tissues [9,10]. It also facilitates water movement in the vascular systems of humans and animals, such as in blood vessels and the microcapillaries of the human body [11]. ...
Several researchers observed a significant increase in water flow through graphene-based nanocapillaries [1-2]. As graphene sheets are flexible [3], we represent nanocapillaries with a deformable channel-wall model by using the small displacement structural-mechanics and perturbation theory presented by [4], and [5], respectively. We assume lubrication assumption in shallow nanochannels, and using the microstructure of confined water along with slip at the capillary boundaries and disjoining pressure [2], we derive the model for deformable nanochannels. Our derived model also facilitates the flow-dynamics of Newtonian-fluids under different conditions [2,4-8]. We compare the experimental observations by [1] and MD-simulation results by [2] with our deformable-wall model. Using the model, we study the effect of flexibility on flow rate. As the flexibility $\alpha$ increases, the flow rate also increases. We find that the flow rate scales as $\dot{m}_{\text{flexible}}\sim \alpha^0 to $\alpha^3 $ as $\Big (\alpha \Delta pW/EH_o \Big ) $ increases. We also find that, for a given thickness, the change in flow rate in the smaller-height channels is more than the larger-height channels with $H_o^{-1}$ to $H_o^{-3}$ after a height-threshold. Further, we investigate how the applied pulsating pressure influences the flow rate. We find that due to the oscillatory pressure field, there is no change in the averaged mass flow rate in the rigid-wall channel, whereas the flow rate increases in the flexible channels with the increasing magnitude of the oscillatory pressure field. Also, in flexible channels, depending on the magnitude of the pressure field, either of the steady or oscillatory or both kinds of pressure field, the averaged mass flow rate dependence varies from $\Delta p$ to $\Delta p^4$ as the pressure field increases. We find that both the flexibility of the graphene sheet and the pulsating pressure fields to these flexible channels intensify the rapid flow rate through nano/Angstrom-size graphene capillaries.
... To address this critical issue, several solutions have been developed and testi ed. For example, creating su cient ion transport channels to boost ion diffusion capacity to alleviate the salt precipitation [25][26][27][28][29][30][31][32][33] . Alternatively, salt-resistant properties can be achieved by incorporating a Janus hydrophilic-hydrophobic structure to segregate water transportation and evaporation regions [34][35][36][37][38][39][40][41] . ...
Interfacial solar evaporation-based seawater desalination is regarded as one of the most promising strategies to alleviate freshwater scarcity. However, the solar evaporation rate of real seawater is significantly constricted by the ubiquitous salts present in seawater. In addition to the common issue of salt accumulation on the evaporation surface during solar evaporation, strong hydration between salt ions and water molecules leads to a lower evaporation rate for real seawater compared to pure water. Here we develop a facile and general strategy to reverse this occurrence, i.e., making the real seawater evaporation faster than pure water. By simply introducing specific mineral materials into the floating photothermal evaporator, ion exchange at air-water interfaces directly resulted in a decrease in seawater evaporation enthalpy, and consequently much higher seawater evaporation rates compared to pure water. This process is spontaneously realized during seawater solar evaporation. Considering the current enormous clean water production from evaporation-based desalination plants, such an evaporation performance improvement could potentially increase annual clean water production by more than a billion tons, benefiting millions of people worldwide.
... Biomass materials offer a sustainable option for solar-driven steam generation due to their biocompatibility, renewability, and sustainability. [25][26][27][28][29][30][31] Evaporators made from natural materials such as wood, [32] algae, [33] mushrooms, [34] and waste rice straw [35] are becoming more common and are often carbonized or used as support when combined with thermal materials. However, challenges still exist for the application of these biomass-based evaporators, leaving room for improvement in their use for solar steam generation. ...
Solar‐driven interfacial water evaporation powered by solar energy has gained significant interest as a sustainable and cost‐efficient desalination technology, owing to its zero reliance on fossil fuels. It aligns the relationship between freshwater demand and environmental‐friendly water yields and provides us with a feasible and effective way to mitigate the global water crisis. Biomass‐derived photothermal evaporators stemming from sustainable and renewable resources and performing high freshwater output have piqued researchers’ interest in achieving water evaporation effectively, economically, and greenly. In this review work, biomass‐based photothermal evaporators coming from hydrogels, carbides, and fibers are summarized and their optical design, wettability, thermal management, and salt‐rejection ability are analyzed, presenting an overview of the current status of biomass‐based materials in the solar‐driven water purification system.
... Water transport through nanocapillaries, such as in biological systems and nanoscale materials, is ubiquitous in the natural world and has many applications in technology [16,17,18,19]. In biological systems, capillary action in nano capillaries enables efficient water transport in plants, allowing them to absorb water from the soil and distribute it throughout their tissues [20,21]. It also facilitates the movement of water in the vascular systems of humans and animals, such as in blood vessels and the microcapillaries of the human body [22]. ...
... As we know for a steady part, the pressure is decreasing along the channel length, therefore we assumed p o ≥ 0. For a meaningful solution we require sgn(c 4,n ) = 1. Hence substituting equations (17), (19), (21), and (22) in equation (13), the generalised velocity profile under pulsating field can be written as ...
Water transport through minuscule pores is widespread in the natural world and holds significant implications in various technological applications [1-4]. Radha et al. [5] has observed a significant increase in the water flow within graphene-based capillaries that are only a few nanometers or Angstrom-sized thick. By applying the Hagen-Poiseuille theory with confined water properties under continuum modelling, along with molecular dynamic simulations, Neek-Amal et al. [6] modelled these capillaries with rigid wall channels and attributed this enhancement to the high density and viscosity of water inside these nano capillaries. As Graphene sheets are flexible [7], we represent these graphene-based nanochannels with a deformable channel-wall model by using the small displacement structural mechanics and perturbation theory presented by Gervais et al. [8], and Christov et al. [9], respectively. We assume the lubrication assumption in the shallow nanochannels, and using the microstructure of confined water along with slip at the capillary boundaries and disjoining pressure Neek-Amal et al. [6], we derive the model for deformable nanochannels. The newly derived model also facilitate the flow dynamics of Newtonian fluids under different conditions as its limiting cases, which has been previously reported in the literature [6,8-12]. Using the model, we study the effect of flexibility of graphene sheet on the flow rate. We also investigate how the applied pulsating pressure influences the behavior of the water flow rate within these flexible nano capillaries, as applying pulsating pressure fields or vibrations is a classical method for enhancing flow-rate of complex fluids through porous mediums such as channels and tube capillaries [13-15]. We compare the prediction of flow rate from both including the flexibility of the channel wall, and the application of pulsating pressure with the experimental observations by Radha et al. [5] and predictions from the molecular dynamic simulation by Neek-Amal et al. [6] which were well fitted by their rigid-wall model. We find that both the flexibility of the graphene sheet and the pulsating pressure fields to these flexible channels intensify the rapid flow rate through nano/Angstrom-size graphene capillaries.
... Compared to traditional seawater purification technologies, such as reverse osmosis and ion exchange, some novel distillation systems show potential for evaporationbased water purification due to high efficiency, low cost, and scalability. In this context, exploring sustainable solar energy to power water evaporation has become a rapidly growing research direction [2,3]. There is a great deal of interest in improving the efficiency of solar desalination, and the key design principles can be broadly summarized as follows: (I) enhancing solar absorption to collect energy from concentrated sunlight and (II) locating heat near the surface of water evaporation to concentrate solar energy to improve energy efficiency. ...
When the typical solar-driven hydrogel water evaporator treats the organic sewage, the organic pollutants will be accumulated in the evaporator and affect the evaporation performance. This issue is resolved by using silver–disulfide bonding to fix the silver oxide/silver (Ag2O/Ag) nanoparticles inside the polyacrylamide-acrylic acid hydrogel, resulting in the photocatalytic degradation of methyl orange and solar-driven water evaporation. Ag2O/Ag nanoparticles are a solar–thermal conversion material used to replace the traditional carbon material. On the one hand, the heterojunction structure of Ag2O/Ag enhances the separation ability of the photogenerated carriers, thereby increasing the photocatalytic efficiency. On the other hand, the surface of the nanoparticles is grafted with N, N′-bis(acryloyl) cystamine and becomes the crosslinking agent which is fixed in the hydrogel. Meanwhile, the inverted pyramid structure can be built at the surface of the hydrogel by soft imprinting technology. This kind of structure has excellent light trapping performance, which can increase the efficiency of Ag2O/Ag photocatalysis. Furthermore, the dynamic reversible coordination effect between Fe3+ and carboxyl realizes the self-healing capability of the hydrogel. Here are the properties of hydrogel: the fracture stress is 0.35 MPa, the fracture elongation is 1320%, the evaporation rate is 1.2 kg·m−2·h−1, and the rate of the photocatalytic degradation of methyl orange is 96% in 3 h. This self-healing hydrogel membrane provides a strategy to steadily get clean water from organic sewage.
... The anisotropic microchannel network promotes the rapid transmission of water and ensures the hydrophilicity of cell wall components (cellulose and hemicellulose). In addition, wood is renewable, self-floating, has low thermal conductivity and good scalability, making it an ideal substrate for manufacture of advanced solar evaporators [81]. ...
