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Clean‐water harvesting through solar interfacial evaporation technology has recently emerged as a strategy for resolving global water scarcity. In this study, rapid carbon‐dioxide‐laser‐induced carbonization and facile ice‐templating is employed to construct a cellulose‐based solar evaporator bearing a hybrid multi‐layer micro‐/nano‐architecture (i.e., a laser‐induced carbon (LC) nanostructure and a cellulose aerogel (CA) nano/microstructure). The LC exhibits a light‐absorbing/photothermal nanoporous carbon structure that offers high light absorption and multiple light scattering. Additionally, the CA exhibits numerous nanopores and unidirectional microchannels that facilitate rapid water transport via capillary action. This hybrid LC/CA micro‐/nano‐architecture enabled rapid vapor generation with an average water evaporation rate (ν) of 1.62 kg m−2 h−1 and an evaporation efficiency (η) of 66.6%. To further enhance the evaporation performance, a polydimethylsiloxane (PDMS) layer is coated onto the side of the LC/CA evaporator to increase its floatability in the simulated water; ν and η of the PDMS‐coated LC/CA evaporator (LC/CA/PDMS) increased to 1.9 kg m−2 h−1 and 83.8%, respectively. Additionally, the LC/CA/PDMS evaporator exhibited a high ν value of 1.68 kg m−2 h−1 in simulated seawater, originating from excellent resistance to salt accumulation via its self‐cleaning ability. Furthermore, the solar evaporator exhibited scalability for fabrication as well as biodegradable properties. [ABSTRACT FROM AUTHOR]

Interfacial solar-driven evaporation technology shows great potential in the field of industrial seawater desalination, and the development of efficient and low-cost evaporation materials is key to achieving large-scale applications. Hydrogels are considered to be promising candidates; however, conventional hydrogel-based interfacial solar evaporators have difficulty in simultaneously meeting multiple requirements, including a high evaporation rate, salt resistance, and good mechanical properties. In this study, a Janus sponge-like hydrogel solar evaporator (CPAS) with excellent comprehensive performance was successfully constructed. The introduction of biomass agar (AG) into the polyvinyl alcohol (PVA) hydrogel backbone reduced the enthalpy of water evaporation, optimized the pore structure, and improved the mechanical properties. Meanwhile, by introducing hydrophobic fumed nano-silica aerogel (SA) and a synergistic foaming-crosslinking process, the hydrogel spontaneously formed a Janus structure with a hydrophobic surface and hydrophilic bottom properties. Based on the reduction of the evaporation enthalpy and the modulation of the pore structure, the CPAS evaporation rate reached 3.56 kg m-2 h-1 under one sun illumination. Most importantly, owing to the hydrophobic top surface and 3D-interconnected porous channels, the evaporator could work stably in high concentrations of salt-water (25 wt% NaCl), showing strong salt resistance. Efficient water evaporation, excellent salt resistance, scalable preparation processes, and low-cost raw materials make CPAS extremely promising for practical applications. [ABSTRACT FROM AUTHOR]

Water scarcity is a serious threat to the survival and development of mankind. Interfacial solar steam generation (ISSG) can alleviate the global freshwater shortage by converting sustainable solar power into thermal energy for desalination. ISSG possesses many advantages such as high photothermal efficiency, robust durability, and environmental friendliness. However, conventional evaporators suffered from huge heat losses in the evaporation process due to the lack of efficient thermal management. Herein, hydrophilic Tencel yarn is applied to fabricate a three-dimensional double-layer fabric evaporator (DLE) with efficient multi-stage thermal management. DLE enables multiple solar absorptions, promotes cold evaporation, and optimizes thermal management. The airflow was utilized after structure engineering for enhanced energy evaporation efficiency. The evaporation rate can reach 2.86 kg·m−2·h−1 under 1 sun (1 kW·m−2), and 6.26 kg·m−2·h−1 at a wind speed of 3 m·s−1. After a long duration of outdoor operation, the average daily evaporation rate remains stable at over 8.9 kg·m−2, and the removal rate of metal ions in seawater reaches 99%. Overall, DLE with efficient and durable three-dimensional multi-stage thermal management exhibits excellent practicality for solar desalination. [ABSTRACT FROM AUTHOR]

Solar desalination is a promising strategy to utilize solar energy to purify saline water. However, the accumulation of salt on the solar evaporator surface severely reduces light absorption and evaporation performance. Herein, a simple and eco‐friendly method to fabricate a 3D gradient graphene spiral sponge (GGS sponge) is presented that enables high‐rate solar evaporation and zero liquid discharge (ZLD) desalination of high‐salinity brine. The spiral structure of the GGS sponge enhances energy recovery, while the gradient network structures facilitate radial brine transport and directional salt crystallization, which cooperate to endow the sponge with superior solar evaporation (6.5 kg m−2 h−1 for 20 wt.% brine), efficient salt collection (1.5 kg m−2 h−1 for 20 wt.% brine), ZLD desalination, and long‐term durability (continuous 144 h in 20 wt.% brine). Moreover, the GGS sponge shows an ultrahigh freshwater production rate of 3.1 kg m−2 h−1 during the outdoor desalination tests. A continuous desalination–irrigation system based on the GGS sponge for crop growth, which has the potential for self‐sustainable agriculture in remote areas is demonstrated. This work introduces a novel evaporator design and also provides insight into the structural principles for designing next‐generation solar desalination devices that are salt‐tolerant and highly efficient. [ABSTRACT FROM AUTHOR]

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Although water is almost transparent to visible light, we demonstrate that the air--water interface interacts strongly with visible light via what we hypothesize as the photomolecular effect. In this effect, transverse- magnetic polarized photons cleave off water clusters from the air--water interface. We use 14 different experiments to demonstrate the existence of this effect and its dependence on the wavelength, incident angle, and polarization of visible light. We further demonstrate that visible light heats up thin fogs, suggesting that this process can impact weather, climate, and the earth's water cycle and that it provides a mechanism to resolve the long- standing puzzle of larger measured clouds absorption to solar radiation than theory could predict based on bulk water optical constants. Our study suggests that the photomolecular effect should happen widely in nature, from clouds to fogs, ocean to soil surfaces, and plant transpiration and can also lead to applications in energy and clean water. [ABSTRACT FROM AUTHOR]

Abstract Solar desalination is a promising strategy to utilize solar energy to purify saline water. However, the accumulation of salt on the solar evaporator surface severely reduces light absorption and evaporation performance. Herein, a simple and eco‐friendly method to fabricate a 3D gradient graphene spiral sponge (GGS sponge) is presented that enables high‐rate solar evaporation and zero liquid discharge (ZLD) desalination of high‐salinity brine. The spiral structure of the GGS sponge enhances energy recovery, while the gradient network structures facilitate radial brine transport and directional salt crystallization, which cooperate to endow the sponge with superior solar evaporation (6.5 kg m−2 h−1 for 20 wt.% brine), efficient salt collection (1.5 kg m−2 h−1 for 20 wt.% brine), ZLD desalination, and long‐term durability (continuous 144 h in 20 wt.% brine). Moreover, the GGS sponge shows an ultrahigh freshwater production rate of 3.1 kg m−2 h−1 during the outdoor desalination tests. A continuous desalination–irrigation system based on the GGS sponge for crop growth, which has the potential for self‐sustainable agriculture in remote areas is demonstrated. This work introduces a novel evaporator design and also provides insight into the structural principles for designing next‐generation solar desalination devices that are salt‐tolerant and highly efficient.

This study integrates multi-effect distillation (MED), multi-stage flash (MSF) evaporation, and solar interface evaporation technologies to enhance water purification processes. We evaluate the material and performance of interface evaporators, with a particular focus on managing the energy balance in solar water evaporation. The research further develops thermal regulation in photothermal materials to maximize light absorption, minimize heat loss, and speed up steam conversion. We employ a novel approach using corn starch and ionic liquid-modified silica hydrogels, noted for their hydrophilicity and broad-spectrum light absorption. The goal is to assess these hydrogels for photothermal conversion efficiency and salt resistance, examining their evaporation performance across various media—pure water, highly saline water, and oily wastewater—and their effectiveness in purifying industrial sewage. Monomer [VEIm]Br and cross-linking agent polymerization occurred to prepare the obtained SiO2 – PILs.Ag / PPy / SiO2 – PILs surface of polypyrrole and Ag particles presenting a three-dimensional porous structure is able to enhance the light absorption performance, between 200-2500 nm range of light absorption rate as high as 90%. Experiments proved the introduction of ionic liquid grafted silica on the introduction of the mechanism to improve the thermal insulation and salt resistance for the actual wastewater purification to provide a strategy.

The emerging solar interfacial evaporation (SIE) technology is an effective measure to address freshwater resources. An efficient and stable solar interfacial evaporator cannot be achieved without the synergy of three key factors: water transport, solar thermal conversion, and thermal management. The performance of a solar interfacial evaporator can be improved through the rational selection of materials and the structural design of these three key factors. Due to superior nanostructures, electrospun nanofibrous materials often exhibit some unique properties that facilitate the construction of solar interface evaporators with good performance. So far, electrospinning has been used to prepare structures such as solar absorbers, water transportation, and thermal insulation in various solar interfacial evaporators. This review presents the fundamental research and technological development in the application of electrospinning techniques to solar interfacial evaporators on structures, morphology, and properties. Then, the latest advances in the use of electrospinning technology in solar interfacial evaporators are summarized and the current issues facing the application of electrospinning technology to solar interfacial evaporators are presented. These systematic discussions can provide ideas and approaches for the rational design of electrospun nanofiber materials for solar interfacial evaporators in the future. [ABSTRACT FROM AUTHOR]

Solar interfacial evaporation significantly improves the efficiency of solar thermal evaporation. However, if the binding strength of the light-absorbing materials to the substrate material is not sufficient, it is easy to shed under the action of external forces in practical applications and reduce the solar-thermal conversion efficiency of the evaporation surface. To solve the problem, this paper proposes a composite surface by wrapping carbon nanotubes on the surface of the cellulose sponge skeleton using polyvinyl alcohol hydrogel. Carbon nanotubes have a good light absorptivity in the wavelength range of 250-2,500 nm. Moreover, the effects of carbon nanotubes concentration, polyvinyl alcohol concentration, and water supply path area on the evaporation performance are also optimized by experiments. The results show that the transparent polyvinyl alcohol not only enhances the binding strength of carbon nanotubes but also does not reduce the light absorptivity of the evaporation surface. Under the optimal ratio of the water supply path area of 20%, at a solar irradiation intensity of 1 kW·m-2, the evaporation rate of the evaporator reaches 1.345 ± 0.034 kg·m-2·h-1 with an evaporation efficiency of 89.7% ± 2.5%, evaporation performance with a long-term stability. This research provides a new method for the design and fabrication of evaporators for seawater desalination applications. [ABSTRACT FROM AUTHOR]

Solar interfacial evaporation (SIE) technology has become an important research content in the water treatment fields gradually. It is low cost and sustainable, especially when water resources are scarce and energy infrastructure is not perfect and can deliver high‐quality freshwater. In recent years, along with the rise of new nanomaterials, water evaporation efficiency improved further; additionally, the efficient evaporation system structure design and thermal managements can improve the absorbance and latent heat recovery efficiently. These advanced researches make SIE efficiency is enhanced markedly, especially in small water evaporation equipment driven by solar energy wholly. It can achieve extremely high steam generation rate and possess an extensive application prospect. In this critical review, the photothermal mechanisms and material types of new photothermal materials, the basic structural design requirements of SIE systems primarily are discussed. On this basis, the applications of SIE techniques in the water–energy relations from the microscopic scale to the molecular level in the past decade are summarized. Finally, bottlenecks of the development of SIE technology, as well as the approaches and opportunities in the future, are discussed critically, new ideas are provided for the long‐range objective of utilizing renewable energy to generate clean water for environmentally sustainable development. [ABSTRACT FROM AUTHOR]

In this work, after carbonization of two biomass wastes, rice husk and coconut husk, they were modified by hydrothermally synthesized cryptomelane manganese and prepared into a solar interfacial evaporation system to explore their evaporation performance and stabilization performance of cadmium. The results demonstrate that the cryptomelane-modified biochar can obtain an evaporation rate of 1.247 kg m−2 h−1 and a photothermal conversion efficiency of 89.36% under one sun (1 kW m−2). In an outdoor experiment with an average solar power density of only 465.22W m−2, the evaporation capacity reached 4.7 kg m−2 and the evaporation rate reached 0.78 kg m−2 h−1 within 6 h. The cadmium adsorption capacity of biomass waste modified by manganese potassium ore increased by 50.94%, which could be well used for long-term stabilization and recycling of Cd. It could be verified that the cryptomelane-modified biochar material is a low-cost, scalable, and efficient material for interfacial evaporation and reduce wastewater pollution. The evaporation system designed in this work is a feasible way to obtain clean water and solve wastewater problems in the future. [ABSTRACT FROM AUTHOR]

Abstract Owing to the lightweight, flexibility, and molecular diversity, organic photothermal materials are considered promising solar absorbent materials for water‐evaporating purification. Herein, we utilize the blend of two organic conjugated photothermal materials, PM6 and Y6, with broadband solar absorption from 350 to 1000 nm and high‐efficiency photothermal properties to fabricate a Janus water evaporator on cellulose paper. Similar to the asymmetric wetting behavior on the lotus leaf, the evaporator shows efficient water adhesion on the bottom surface and water repellency on the top surface for a desirable self‐floating capability and salt resistance. With a mass of only 0.5 mg per 3.14 cm2, the PM6:Y6 blend‐based water evaporator achieves 88.9% of solar thermal conversion efficiency (η) and 1.52 kg m−2 h−1 of solar water evaporation rate (m) under 1.0 kW m−2 solar irradiation. These properties are almost the best performance among purely organic water evaporators especially with such a premise of material saving. The concentrations of primary ions are significantly decreased by 4–6 orders after desalination, accompanied by excellent performance for wastewater treatment. This evaporator realizes a m of 1.21 kg m−2 h−1, a η of 75.7%, and a voltage of 61 mV under one sun irradiation by assembling with a thermoelectric equipment. This study demonstrates that the blending of PM6 and Y6 achieves photothermal synergism, which improves the photothermal property and water evaporation rate, providing a valuable prospect for their application in water purification and thermoelectric power generation.

Solar interfacial water evaporation to obtain pure water has attracted extensive attention in recent years. In this work, based on the excellent optical property of FeS2 and the cross-linking nanostructure of chitosan (CTS), a FeS2@CTS hydrogel composite film for solar interfacial water evaporation was developed by hydrothermal synthesis and the following composite coating technology. The prepared FeS2@CTS presented high solar absorptivity of 95.27% and fast optical response capability. Under the optimized condition, the evaporation rate of pure water reached 3.34 kg m−2 h−1 and the photothermal conversion efficiency was 103.06% under one sun irradiation. In five runs, the evaporation rate of the FeS2@CTS was stable, indicating the excellent cycle stability. Also, in the desalination test, the stable evaporation rate of 1.74 kg m−2 h−1 was obtained in five runs. Due to the simple preparation method, low cost, and outstanding interfacial evaporation property, this FeS2@CTS indicates great potential for the seawater desalination or other photothermal conversion applications. [ABSTRACT FROM AUTHOR]

Solar interfacial evaporation based oil/water separation using wood-melamine/calcium alginate composite with black cotton. [Display omitted] • An effective solar interfacial evaporator is designed for oi/water separation. • A hydrophilic-oleophobic wood-melamine/calcium alginate composite is designed. • A water evaporation rate of 5.74 kg•m−2•h−1 is obtained under 5 solar suns. • Oil volume fraction of condensed water is significantly less than 0.2%. Solar interfacial evaporation is an attractive phenomenon for water treatment using renewable energy without further environmental contamination. However, the existing researches mainly focus on improving water evaporation rate with diversified interfacial and porous materials for solar absorption and water transport. The oil/water separation from emulsion under solar interfacial evaporation is rarely investigated. Under these circumstances, a wood-melamine/calcium alginate composite structure with hydrophilic and oleophobic characteristics is designed and fabricated in the current work to realize solar interfacial evaporation based oil/water separation from emulsion. The corresponding oil/water separation process is experimentally analyzed under different material composite structures, solar intensities, and oil volume fractions. The wood-melamine/calcium alginate composite structure exhibits outstanding oil/water separation capability from emulsion under solar interfacial evaporation in comparison to the pure wood and wood-calcium alginate membrane structures owing to its fantastic oil resistance and water permeation properties. Through optimizing the thickness and aperture of hollow wood cylinder, a maximum interfacial water evaporation rate of 5.74 kg•m−2•h−1 is achieved under 5 sun solar intensity for oil/water separation. Besides, an outdoor experiment under natural sunlight (622 W•m−2 to 769 W•m−2) in summer time is also carried out for oil/water separation from emulsion using designed wood-melamine/calcium alginate composite under interfacial evaporation, and an average water evaporation rate of 0.965 kg•m−2•h−1 is obtained with condensed water on the hydrophobic glass cover for recovery. The current research paves an effective route for handling oil-in-water emulsion using renewable solar energy, contributing to the water resource protection and environmental sustainable development. [ABSTRACT FROM AUTHOR]

A novel interfacial solar steam generators (ISSG) was prepared by a porous carbon black/polyvinyl acetal aerogel (CPA) with high light-absorbing hydrophilic properties, to achieve efficient solar-driven water evaporation and seawater desalination. The polyvinyl acetal was produced by the aldol condensation reaction of polyvinyl alcohol(PVA) and glutaraldehyde(GA). It was freeze-dried to create a hydrophilic porous structure that constructs an efficient hydrophilic channel. Carbon black (CB) exhibits high light absorption capabilities. Incident light undergoes multiple scattering within its porous network structure, effectively reducing reflected light energy loss and enabling efficient thermal conversion of sunlight. Benefited from its highly light-absorbing porous hydrophilic structure, CPA-40-3 evaporation rate achieves an impressive 3.23 kg·m−2·h−1 and an evaporation efficiency of 94 % under 1 sun irradiation, without obvious decay even during long-term use. Furthermore, CPA-40-3 demonstrates remarkable salt tolerance, the evaporation rate remains at 2.55 kg·m−2·h−1 although in simulated Dead Sea salt water under 1 sun irradiation. Compared to traditional ISSG, the CPA has advantages such as superior mechanical properties, prevention of surface salt precipitation, faster water supply, and a larger light absorption area. This design had tremendous promise for efficient solar desalination due to its extraordinarily high evaporation performance in high-salinity brine. [Display omitted] • A new strategy was designed to prepare CB/PVA aerogel by regulating the channel structure and surface energy. • The evaporation rate of 3.23 kg·m−2·h−1 with an efficiency of 97 % is achieved. • The evaporator can keep an efficient evaporation rate of 1.96 kg·m−2·h−1 in a simulated Dead Sea environment under 1 sun. • The evaporator shown excellent desalination capacity. [ABSTRACT FROM AUTHOR]

Acidic wastewater comes from a wide range of sources in industrial process. The traditional treatment method of acidic wastewater is acid-base neutralization which consumes a lot of chemicals. In recent years, much attention has been paid to the treatment of wastewater through solar interfacial evaporation. However, many of the reported evaporators present challenges in terms of poor acid resistance and costly raw materials. In this article, the three-dimensional porous MXene/PPAL aerogel was prepared by directional freeze-drying using inexpensive Palygorskite (Pal) and renewable pectin, then a moderate amount of MXene was sprayed onto the aerogel surface to create a double-layer solar evaporator. The prepared evaporator exhibited great mechanical properties with a compressive strength of 0.85 MPa at 70 % strain, and high vapor rate of 1.5474 kg m−2 h−1 that equals 94.7 % photothermal conversion efficiency. Furthermore, photothermal conversion efficiency of the solar evaporator in 5 % H 2 SO 4 solution (p H = 1) was 90.2 %, which was only slightly different from that in pure water. The results provided a new technology that easy recovery of acidic wastewater and reused treated water from industrial acidic wastewater through economical and efficient solar interfacial evaporation. [Display omitted] • MXene-PPAL has advantages of low cost, simple and scalable manufacture process. • MXene-PPAL shows excellent energy conversion efficiency of 94.7 % under 1 sun irradiation. • MXene-PPAL shows excellent acid resistance with a high energy conversion efficiency of 90.2 % obtained even in 5 wt% H 2 SO 4 under 1 sun irradiation. [ABSTRACT FROM AUTHOR]

The 3D steam generator with cold evaporation surface (CES) provides a means for high‐efficiency interfacial steam generation due to the low heat loss and continuous ambient energy input. However, the poor floating stability of CES steam generators when suffering wave slamming has limited their practical application in open water. Herein, a cellulose‐based monolithic aerogel integrated with three structural elements is developed inspired by tumblers, which can synchronously achieve outstanding antioverturning stability in waves and a high evaporation rate (4.21 kg m−2 h−1). A single‐stage solar water purification device is constructed based on the photothermal aerogel, which attains an ultra‐high daily water yield of ≈32.6 L m−2 and surpasses a large amount of single‐stage solar stills. The steam generator can also be used to purify wastewater containing Co2+ via adsorption. Gratifyingly, the Co3O4/C catalyst obtained from the pyrolysis of aerogels loaded with Co2+ exhibits good catalytic activity for carbon monoxide oxidation, demonstrating the potential for waste conversion. This work provides new insights into the design of solar steam generators used in open water, and offers a promising way for the disposal and utilization of contaminated steam generators after wastewater purification. [ABSTRACT FROM AUTHOR]

The world faces a trade-off between water availability and food supply, as agricultural irrigation consumes the largest freshwater globally. Inspired by inherent water transport channels in plants, a cost-effective welding pollen-based solar evaporator (PSE) is developed to obtain clean water from seawater desalination. Based on the convex and folded surface structure of natural pollen (Helianthus annuus) and the porous structure of welding pollen evaporator interconnection, the PSE reveals an efficient evaporation rate of 1.86 kg m -2 h -1 under one-sun illumination and further exhibits excellent cycling performance for 10 cycles tested in 7.0 wt.% saline water without salt accumulation. In addition, PSE has superior mechanical stability (3.44 MPa) and remains stable after being immersed in pH 1 and 14 solutions for 24 h without sacrificing mechanical properties. Importantly, the work has demonstrated the success of the freshwater collected from the evaporation process, which can effectively facilitate the cultivation of lettuce, rice, and wheat. These findings highlight the practical application of pollen as a low-cost, eco-friendly natural resource in interfacial solar evaporation. Furthermore, they inspire addressing current global water scarcity and promoting sustainable agriculture., (© 2024 Wiley‐VCH GmbH.)

Solar‐powered interfacial evaporation has emerged as an innovative and sustainable technology for clean water production and it has motivated the design and fabrication of monolithic 3D steam generators and related hybrid applications. However, the existing porous and hydrophilic 3D scaffolds fabricated via conventional processing techniques remain one of the main roadblocks toward scalable and mass applications. Herein, a series of closed‐cell 3D polymer foams is developed via a "rotating" gas‐foaming technique. Monopile supporting structures with reticulated and hydrophilic gas pockets are formed in the 3D foams, resulting in controlled shapes and heights, ultralight weight, efficient water diffusion, and optimized solar and environmental energy input. Gratifyingly, the 3D foam with a selected height of 12 cm attains an outstanding water evaporation rate of 5.8 kg m−2 h−1 under 1 sun. Furthermore, selected photothermal, adsorbent, and photocatalytic materials on the 3D foam introduce water remediation beyond clean water production, exhibiting organic pollutant removal efficiencies over 90% in indoor and outdoor experiments. An ease‐of‐mold approach to shape‐controlled fabrication of polymer foams is demonstrated and their intriguing properties for solar‐powered hybrid applications such as organic pollutant removal in wastewater are highlighted. [ABSTRACT FROM AUTHOR]

Abstract Solar interfacial evaporation holds great potential for desalination. Currently, abundant and renewable biomass appears to be the most sustainable evaporator candidate for addressing environmental and energy challenges. However, the widespread use of biomass‐based evaporators is hampered by the formation and deposition of salt on the evaporation surface. Herein, we present a hierarchical photothermal aerogel inspired by the leaves‐on‐stems architecture in pristine plants. It is formed with microchannels severing as stems and nanospikes as leaves. Microchannels with large pores enable quick brine replenishment, while numerous nanospikes increase the available surface area for vapor generation. In contrast to the macro‐scale salt‐resistant design, which ruins the overall structure of the evaporator, we modified the microchannel structure within the biomass, allowing the biomass evaporator to effectively resist salt while maintaining efficient evaporation performance. The unique hierarchical micro‐nano structure of this photothermal aerogel allows it to achieve a high evaporation rate of 1.78 kg m−2 h−1 under 1 sun and a continuous evaporation time of 100 h without salt deposition in a high‐salinity brine (15 wt%), outperforming most previously reported evaporators derived from biomass. Additionally, the anti‐biofouling capacity of the evaporator is effectively demonstrated for long‐term operation through the development of an enhanced freshwater collection prototype, highlighting the potential for sustainable off‐grid solar desalination.

The scarcity of freshwater resources and energy crisis are major challenges to the progress of human society. Recently, solar-driven interfacial water evaporation utilizes photothermal conversion materials to convert solar energy into thermal energy, which possesses great application potential in seawater desalination and sewage treatment. Here, we fabricated porous nickel sponge (NSP) composite photothermal material (NiO-NSP) containing abundant NiO nanoneedles array. This in situ-grown NiO with enhanced bonding between photothermal material and substrate can be used as a solar absorber directly without consuming additional photothermal material compared to conventional coating and cladding on the carrier surface. Due to the multi-scattering induced light trapping effect of the semiconductor NiO nanoneedles array on the surface of nickel fibers, resulting in light absorption up to 96.5 %. NiO-NSP evaporators have an abundance of interconnected porous channels for water supply, which results in strong capillary action to pump water to the evaporation interface efficiently. Moreover, the highly dispersed nanoneedles array expand the evaporation surface area. Consequently, the NiO-NSP evaporator delivers an excellent evaporation rate of 1.78 kg m−2 h−1 and a photothermal conversion efficiency of 84.7 % at one sun radiation. In addition, the micron-sized porous mesh structure of NiO-NSP dissolve salt crystals and diffuse them downward into the bulk brine, exhibiting excellent salt resistance and remarkable seawater desalination stability. Moreover, NiO-NSP solar evaporators has been demonstrated to possess excellent ability to purify dye and heavy metal ion wastewater. Therefore, the NiO-NSP high-performance evaporator produced by straightforward process proved to be suitable for solar seawater desalination and wastewater purification. [Display omitted] [ABSTRACT FROM AUTHOR]

Solar interface evaporation technology has gained significant attention in the field of seawater desalination due to its environmentally friendly and sustainable characteristics. However, the efficient and stable application of solar evaporators still presents challenges in terms of material and structural design. The wood solar evaporator offers a promising solution as it meets the requirements of cost-effectiveness, ease of preparation, and environmental friendliness by utilizing the inherent channel structure of wood for seawater desalination. The paper introduces the structural principle of an Integrated Solar Still-Greenhouse (ISSG) system and highlights the advantages provided by wood solar evaporators within this system, including their unique wood hole structure and excellent thermal insulation performance. Additionally, various common methods for preparing wood solar evaporators are summarized (such as surface carbonization, coating deposition, wrapping, impregnation). Emphasis is placed on discussing the structural design of wood evaporators along with strategies for adjusting their functionality and stability. Finally, this paper addresses challenges faced by wood evaporators while suggesting future development directions that offer novel insights. • The working mechanism of solar interface evaporator is summarized. • The application of wood in solar energy evaporator is described. • The efficient preparation methods of wood solar evaporator are reviewed. • The stability and multifunctional application of wood evaporator are described. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nowadays, freshwater crisis seriously challenges human survival and development. • Solar desalination is promising in collecting clean water, but only feasible in regions with available surface water. • Atmospheric water harvesting is independent of surface water but requires high humidity and complex equipments. • In this study, efficient water harvesting from desert soil in very dry regions is achieved via interfacial solar heating under natural sunlight. • The portable and scalable water harvesting device, composed of merely a thin layer of activated carbon, a commercially available polyethylene film and a water container, could collect 1.13 kg of clean water per square meter of desert soil per day. Freshwater crisis seriously challenges human survival and development, especially in arid regions. Solar-driven interfacial evaporation has recently received tremendous interest for collecting clean water, yet is only feasible in regions with available surface water. Atmospheric water harvesting is independent of surface water but requires high RH, additional energy input and complex equipment. Here, we demonstrate efficient water harvesting from desert soil in very dry regions (air RH < 10%, soil moisture content < 3%) via interfacial solar heating under natural sunlight. The water harvesting device, composed of merely a thin layer of activated carbon (for interfacial solar heating on soil surface), a commercially available polyethylene film (for vapor condensation and water transport) and a water container, could collect 1.13 kg of clean water per square meter of desert soil per day (8 h), i.e., 0.53 kg of clean water per kilogram of activated carbon per hour, under a solar flux of 0.26–0.55 kW m−2. Besides, the soil water harvesting system is very portable, low-cost and scalable. This work opens up a new sustainable approach for solving the freshwater crisis in arid and impoverished regions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Inspired plant, a novel carbon fiber-based evaporator device comprised of carbon fiber bundles (CFBs) and perforated wood, is designed for solar steam generation. • Vertical CFBs can realize broadband efficient light absorption and effectively supply water, enabling the proposed evaporator to achieve a high evaporation performance. • The plant-inspired device with scalability, feasibility, and low cost opens an avenue for designing and developing high-efficiency interfacial solar evaporators. Solar interfacial steam generation technology has been recognized as a highly desirable way to relieve the shortage of freshwater resources. However, the preparation of a high-performance salt-resistant evaporator with a simple fabrication process is challenging. Herein, a plant-inspired device comprised of several carbon fiber bundles (CFBs) and perforated wood is designed. Vertical CFBs can realize broadband efficient light absorption, and the capillary force of microchannels between carbon fibers can effectively supply water. The perforated wood holds CFBs in place, and the buoyancy of wood keeps the entire evaporator afloat. Adjusting the fineness and height of CFBs can control the steam generation rate. In the experiment simulating one sun's illumination, the evaporation rate of the optimized plant-inspired device is able to stabilize at 1.70 kg m−2h−1 and can effectively avoid salt crystallization for long periods of simulated seawater evaporation (3.5% NaCl solution). Benefiting from the inherent characteristics of carbon fibers and wood, this device also exhibits ultrahigh chemical stability. This plant-inspired evaporator from carbon fibers opens an avenue for the manufacture of simple and high-efficiency interfacial solar evaporators. [ABSTRACT FROM AUTHOR]

Solar-powered interfacial water evaporation is a promising technique for alleviating freshwater stress. However, the evaporation performance of solar evaporators is still constrained by low photothermal conversion efficiency and high water evaporation enthalpy. Herein, 0D carbon quantum dots (CQDs) are combined with 2D MXene to serve as a hybrid photothermal material to enhance the light absorption and photothermal conversion ability, meanwhile sodium carboxymethyl cellulose (CMC)/polyacrylamide (PAM) hydrogels are used as a substrate material for water transport to reduce the enthalpy of water evaporation. The synergistic effect in 0D CQDs/2D MXene hybrid photothermal materials accelerate the carrier transfer, inducing efficient localized surface plasmon resonance (LSPR) effect. This results in the enhanced photothermal conversion efficiency. The integrated hydrogel evaporators demonstrate a high evaporation rate (1.93 and 2.86 kg m -2  h -1 under 1 and 2 sunlights, respectively) and low evaporation enthalpy (1485 J g -1 ). In addition, the hydrogel evaporators are applied for photothermal sensing and temperature difference power generation (TEG). The TEG device presents an efficient output power density (230.7 mW m -2 ) under 1 sunlight. This work provides a feasible approach for regulating and controlling the evaporation performances of hydrogel evaporators, and gives a proof-of-concept for the design of multipurpose solar evaporation systems., (© 2024 Wiley‐VCH GmbH.)

Facing the increasing global shortage of freshwater resources, this study presents a suspended multilayer evaporator (SMLE), designed to tackle the principal issues plaguing current solar-driven interfacial evaporation technologies, specifically, substantial thermal losses and limited water production. This approach, through the implementation of a multilayer structural design, enables superior thermal regulation throughout the evaporation process. This evaporator consists of a radiation damping layer, a photothermal conversion layer, and a bottom layer that leverages radiation, wherein the bottom layer exhibits a notable infrared emissivity. The distinctive feature of the design effectively reduces radiative heat loss and facilitates dual-interface evaporation by heating the water surface through mid-infrared radiation. The refined design leads to a notable evaporation rate of 2.83 kg m -2 h -1 . Numerical simulations and practical performance evaluations validate the effectiveness of the multilayer evaporator in actual use scenarios. This energy-recycling and dual-interface evaporation multilayered approach propels the design of high-efficiency solar-driven interfacial evaporators forward, presenting new insights into developing effective water-energy transformation systems., (© 2024 Wiley‐VCH GmbH.)

Solar interfacial water evaporation is considered as a potential green technology to solve the global shortage of freshwater resources. However, it is still an arduous task to develop a low-cost and efficient solar evaporator with a simple preparation method. Herein, a simple, flexible, and porous polypyrrole-wax gourd (PPy-wax gourd) biomass evaporator was reported for solar evaporation enhancement. Wax gourd had the advantages such as superhydrophilic wettability, massive microporous channels, and easy planting. PPy was a kind of black polymer with excellent light absorption ability, which greatly improved the light absorption of the PPy-wax gourd evaporator within a full spectrum of solar irradiance (300-2500 nm). The PPy-wax gourd evaporator prepared by the perfect combination of wax gourd and polypyrrole realized a superior vapor generation ability (1.57 kg m-2 hours-1) with a photothermal conversion efficiency of 77.3% under 1 solar intensity, which was better than some other biomass evaporators developed so far. In addition, the PPy-wax gourd evaporator also exhibited remarkable stability and durability under long-term recycling utilization and harsh environments. Importantly, the PPy-wax gourd evaporator demonstrated prominent wastewater purification capacity and desalination performance for dye wastewater and simulated seawater treatment. Based on these results, this work would offer a new strategy for developing novel biomass thermal evaporators the clean water production. [ABSTRACT FROM AUTHOR]

Solar‐driven interfacial evaporation has emerged as an innovative and sustainable technology for efficient, clean water production. Real‐world applications depend on new classes of low‐cost, lightweight, and robust materials that can be integrated into one monolithic device, which withstands a variety of realistic conditions on open water. Self‐repairing building blocks are highly desired to prevent permanent failures, recover original functions and maintain the lifetime of interfacial steam generators, although related studies are scarce to date. For the first time, a monolithic, durable, and self‐floating interfacial steam generator with well‐defined structures is demonstrated by integrating self‐healing hydrogels through facile processes in surface modulation and device fabrication. High and stable water evaporation rates over 2.0 kg m−2 h−1 are attained under 1 sun on both fresh water and brine with a broad range of salinity (36–210 g kg−1). The solar evaporation and desalination performance are among the best‐performing interfacial steam generators and surpass a majority of devices that are constructed by composite polymers as structural components. This study provides a perspective and highlights the future opportunities in self‐healing and damage‐tolerant materials that can simultaneously improve the performance, durability, and lifetime of interfacial steam generators in real‐world applications. [ABSTRACT FROM AUTHOR]

Solar interfacial evaporation, featured by high energy transfer efficiency, low cost, and environmental compatibility, has been widely regarded as a promising technology for solar desalination. However, the interplay between energy transfer and water transport in the same channels suggests that the tradeoff between high efficiency and long-term stability inherently exists in conventional photothermal nanomaterials. We summarize state-of-the-art research on various anti-salt clogging photothermal microstructures as long-term stable interfacial solar evaporators for solar desalination. The review starts with an overview of the current status and the fundamental limit of photothermal materials for solar desalination. Four representative strategies are analyzed in detail with the most recent experimental demonstrations, including fluid convection enhancement, surface wettability engineering, energy-mass-path decoupling, and surface chemistry engineering. Finally, this article focuses on the challenges in anti-salt clogging solar interfacial evaporators and potential point-of-use applications in the future.

• There is an optimal absorption coefficient (200 m−1) to improve evaporation performance. • Large contact angles (89.85°) with limited wick rate can be beneficial to the efficiency. • The surface emissivity is important only at concentrated solar irradiation (>4000 W m−2). • The evaporation efficiency can exceed 100% by tuning the temperature, relative humidity, and wind speed. Understanding coupled multiphysical phenomena within solar interfacial evaporation devices is crucial for optimizing materials and device configurations, thereby advancing the engineering of high-performance water production systems. The quantitative assessment of optics, heat, and mass transfer offers guidance for the evaporator's material selection and optimal structural design. This work employs an integrated numerical and experimental method for high-fidelity prediction of evaporation performance under various material choices, device configurations as well as operational conditions. Meanwhile, the multiphysics model we developed was validated and corrected through dedicated experiments. Firstly, we optimized the wicking and light absorption properties and showed that weak wicking rates (θ = 89.85°) and appropriate absorption coefficients (α = 200 m−1) lead to half-full substrates for high evaporation efficiencies. We find that the benefit of low emissivity of absorber surface can only be observed at solar concentrations larger than 4 suns. Meanwhile, we find that by adjusting the ambient temperature, relative humidity and wind speed, evaporation efficiency can exceed 100 % due to the absorption of energy from the surroundings. This study provides a systematic understanding of the coupled multi-mode heat and mass transfer and light propagation mechanisms in solar interfacial evaporation systems, providing guidelines for the rational design for practical applications. [ABSTRACT FROM AUTHOR]

Previous researches on carbon-based solar interfacial evaporation (SIE) have mainly focused on improving the solar absorption, neglecting the effect of water state on the SIE performance. This study proposes an easy strategy by combining carbonization and sulfonation using corncob as the carbon source and concentrated sulfuric acid (H 2 SO 4) as the sulfonating agent to obtain sulfonated carbonized corncob (SCC) samples. The intermediate water to free water (IW/FW) ratio in the range of 0.53–0.96 within SCC samples has been tailored, which depends on the amount of hydrophilic sulfonic acid groups grafted on SCC. It is found that the amount of hydrophilic sulfonic acid groups and porous structure should be optimal in SCC for high IW/FW ratio. The optimized sample named as SCC-2-4.5 with a high IW/FW ratio of 0.96 and similar surface area to carbonized corncob exhibits the low enthalpy of water evaporation of 1800 J g−1, achieving the evaporation rate of 3.16 kg m−2 h−1 and evaporation efficiency of 159%. Meanwhile, SCC-2-4.5 realizes an effective separation of Na+ and Cl−, thanks to the electrostatic repulsion caused by its negatively charged sulfonic acid groups. This study provides an effective technique for regulating water state for carbon-based SIE devices on the molecular level. Modulation of the ratio of intermediate water to free water (IW/FW) on sulfonated corncobs (SCCs) to improve the performance of evaporation devices was demonstrated. The IW/FW ratio of SCCs in the range of 0.53–0.96 were obtained by tailoring the amount of hydrophilic sulfonic acid groups. The optimized SCC sample with a high IW/FW ratio of 0.96 exhibits the low enthalpy of water evaporation of 1800 J g−1, achieving the evaporation rates of 3.16 kg m−2 h−1, evaporation efficiency of 159% and salt resistance value of 1.62 g. Above results show that the sulfonic acid groups play an important role in activating the water state and conferring salt resistance. [Display omitted] [ABSTRACT FROM AUTHOR]

Traditional photocatalytic materials have low catalytic efficiency due to their weak absorption capacity of light. As a new technology to obtain fresh water from seawater or sewage by using sunlight, solar interface evaporation has attracted wide attention. Therefore, it is urgent to explore new composite materials with synergistic interfacial evaporation and photocatalytic properties. A ternary integrated heteroconjunctival membrane (PCC-IS/M@TiO 2) with excellent solar interfacial evaporation and photocatalytic properties has been prepared by two-step hydrothermal method and phase transformation method. Under the condition of 1 kW m−2 simulated solar illumination, the evaporation rate of the composite film can reach 1.4898 kg m−2 h−1, and the photothermal conversion efficiency can reach 82.93 %. It also has good photocatalytic performance on RhB and MB, with degradation rates of 93.34 % and 94.79 %, respectively. In addition to its recyclability and good recycling ability, its practical application ability has also been verified in outdoor experiments. PCC-IS/M@TiO 2 has great application potential in the study of interfacial evaporation synergistic photocatalytic degradation of organic pollutants, and provides a new idea for exploring the design of functional composite materials for treating more complex pollutant water bodies. TiO 2 nanosheets embedded with Ti 3 C 2 MXene (M@TiO 2) and supported with In 2 S 3 (IS) were in-situ synthesized by a two-step hydrothermal method, and the powder was doped in the casting solution, then the photocatalytic heterogeneous conjunctiva (PCC-IS/M@TiO 2) with excellent solar interfacial evaporation and photocatalytic performance were prepared by modification. Under 1 kW m−2 simulated solar illumination, the evaporation rate and photothermal conversion efficiency of the composite membrane can reach to 1.4898 kg m−2 h−1 and 82.93 %, respectively. It also has excellent photocatalytic performance to the organic dyes RhB and MB, with degradation rates of 93.34 % and 94.79 %, respectively. Moreover, compared with pure powder catalyst, it also has good recycling ability when after three times of recycling it can still maintain good photocatalytic ability. This study may provide new ideas for new multifunctional composites loaded with MXene-derived ternary photocatalysts. And PCC-IS/M@TiO 2 has great application potential in the study of interface evaporation and photocatalytic degradation. [Display omitted] • The ternary integrated heteroconjunctiva was prepared by two-step hydrothermal method and phase transformation method, and it was tested by outdoor experiment that it has certain practical application value. • Heterogeneous conjunctiva has good solar interface evaporation performance. Under 1kW m-2 simulated solar irradiation, the evaporation rate of composite film can reach 1.4898 kg m-2 h-1, and the photothermal conversion efficiency can reach 82.93%. • Heterogeneous conjunctiva also showed good photocatalytic performance for organic dyes RhB and MB, with degradation rates of 93.34% and 94.79%, respectively. In addition, it also has good recycling ability and recyclability compared to powder catalysts. [ABSTRACT FROM AUTHOR]

Solar‐driven interfacial evaporation is an emerging technology with a strong potential for applications in water distillation and desalination. However, the high‐cost, complex fabrication, leaching, and disposal of synthetic materials remain the major roadblocks toward large‐scale applications. Herein, the benefits offered by renewable bacterial cellulose (BC) are considered and an all‐cellulose‐based interfacial steam generator is developed. In this monolithic design, three BC‐based aerogels are fabricated and integrated to endow the 3D steam generator with well‐defined hybrid structures and several self‐contained properties of lightweight, efficient evaporation, and good durability. Under 1 sun, the interfacial steam generator delivers high water evaporation rates of 1.82 and 4.32 kg m−2 h−1 under calm and light air conditions, respectively. These results are among the best‐performing interfacial steam generators, and surpass a majority of devices constructed from cellulose and other biopolymers. Importantly, the first example of integrating solar‐driven interfacial evaporation with water wave detection is also demonstrated by introducing a self‐powered triboelectric nanogenerator (TENG). This work highlights the potential of developing biopolymer‐based, eco‐friendly, and durable steam generators, not merely scaling up sustainable clean water production, but also discovering new functions for detecting wave parameters of surface water. [ABSTRACT FROM AUTHOR]

Although water is almost transparent to visible light, we demonstrate that the air-water interface interacts strongly with visible light via what we hypothesize as the photomolecular effect. In this effect, transverse-magnetic polarized photons cleave off water clusters from the air-water interface. We use 14 different experiments to demonstrate the existence of this effect and its dependence on the wavelength, incident angle, and polarization of visible light. We further demonstrate that visible light heats up thin fogs, suggesting that this process can impact weather, climate, and the earth's water cycle and that it provides a mechanism to resolve the long-standing puzzle of larger measured clouds absorption to solar radiation than theory could predict based on bulk water optical constants. Our study suggests that the photomolecular effect should happen widely in nature, from clouds to fogs, ocean to soil surfaces, and plant transpiration and can also lead to applications in energy and clean water., Competing Interests: Competing interests statement:The authors declare no competing interest.

Abstract The past few years have witnessed a rapid development of solar‐driven interfacial evaporation, a promising technology for low‐cost water desalination. As of today, solar‐to‐steam conversion efficiencies close to 100% or even beyond the limit are becoming increasingly achievable in virtue of unique photothermal materials and structures. Herein, the cutting‐edge approaches are summarized, and their mechanisms for photothermal structure architecting are uncovered in order to achieve ultrahigh conversion efficiency. Design principles to enhance evaporation performance and currently available salt‐rejection strategies for long‐term desalination are systematically investigated. The guidelines to utilize every component in solar desalination systems for simultaneous in situ energy generation are also revealed. Finally, opportunities and challenges for future works in this field are also discussed and concluded.

The past few years have witnessed a rapid development of solar‐driven interfacial evaporation, a promising technology for low‐cost water desalination. As of today, solar‐to‐steam conversion efficiencies close to 100% or even beyond the limit are becoming increasingly achievable in virtue of unique photothermal materials and structures. Herein, the cutting‐edge approaches are summarized, and their mechanisms for photothermal structure architecting are uncovered in order to achieve ultrahigh conversion efficiency. Design principles to enhance evaporation performance and currently available salt‐rejection strategies for long‐term desalination are systematically investigated. The guidelines to utilize every component in solar desalination systems for simultaneous in situ energy generation are also revealed. Finally, opportunities and challenges for future works in this field are also discussed and concluded. [ABSTRACT FROM AUTHOR]

• Gradient structure demonstrates an enhanced capillary effect. • Gradient structure can hinder water flow and inhibit heat convection loss. • An evaporation efficiency of 93.4% is achieved under 1 sun illumination. • Template method (Teflon-glass) is used to prepare gradient structured hydrogel. • Microgels are attracted by the Teflon plate showing gradient distribution. Solar interfacial evaporation is a promising way to generate clean water from seawater using clean, abundant, and sustainable solar energy. However, non-directionally moving water with high thermal conductivity acts inevitably as a medium for heat transfer from the surface to the bottom through heat convection, resulting in low energy efficiency and a low evaporation rate. Herein, a gradient structured composite hydrogel combining a desired functional differentiation is reported. The network sizes in the hydrogel continuously change, demonstrating an enhanced capillary effect and a direction-limited water supply capability, inhibiting the heat convection loss. In addition, the reported gradient hydrogel shows broadband light absorption, satisfactory mechanical properties under a saturated swelling state, an unusually higher water evaporation rate for brine compared with that for pure water, and an inherent ability to evaporate under both 1 sun illumination and dark environment. The proposed gradient channels to restrict the flow direction of liquid, and consequently the heat convection loss, will have an significant impact on the design of other efficient photothermal evaporation systems and even the field of mass and heat transfer. [ABSTRACT FROM AUTHOR]

[Display omitted] • A robust and efficient evaporator was designed based on features of sunflower pith. • A soaking process was used to activate hydrophilic groups and encapsulate water. • Water encapsulated inside provided a powerful support to resist compression. • High evaporation rate of 3.39 kg·m−2·h−1 under 1 sun was realized. • Remarkable stability and durability even for 20 wt% brine was achieved. Solar interfacial evaporation (SIE) is a promising method to generate freshwater from unconventional water resources. Using hydrogel materials to activate water molecules has been demonstrated as a facile way to achieve high SIE performance. However, as for hydrogel and hydrogel-analogous evaporators, there is a trade-off between SIE performance and mechanical property due to their high water content and porous structure. Herein, we demonstrate a low-cost and robust sunflower-pith-based hydrogel-like evaporator by simple dip-coating and soaking process. The rigid cellular framework and water encapsulated inside endow this evaporator with excellent compressive strength, which achieves 400.3 ± 64.1 KPa at compressive strain of 80 %. In the meantime, natural ultralow water vaporization enthalpy and ability to capture thermal energy from surroundings enable this evaporator to achieve an outstanding water evaporation rate of 3.39 kg·m−2·h−1 with an energy efficiency of 100.2 % under 1 sun. Moreover, this evaporator exhibits a potential for round-the-clock operation since its evaporation rate can reach 1.14 kg·m−2·h−1 in dark. After introducing artificial open channels, this evaporator shows remarkable stability and durability even for 20 wt% brine. This work provides a sustainable choice for efficient desalination and freshwater production, and offers a guideline for the bionic design of SIE materials. [ABSTRACT FROM AUTHOR]

• Accelerate the adsorption and the enrichment of iodine ions under the simulated light source. • Concentration of iodine ions of collected condensate was decreased three orders of magnitudes. • High photothermal conversion efficiency (95.39%) and water evaporation rate (1.5879 kg m−2 h−1). Solar steam generation has recently received much attention as a new green and environmentally responsible technology for seawater desalination or wastewater treatment. Hence, a novel and efficient strategy is proposed for removal of radioactive iodine ions from wastewater by SSG method using carbonized conjugated microporous polymers (CCMPs) as photothermal conversion materials. Because of the porous structure and strong light absorption of the CCMPs-based interfacial evaporator and the excellent thermal insulation of the expandable polyethylene sponge, CCMP-1 evaporator achieved a high photothermal conversion efficiency (95.39%) and stable water evaporation rate (1.5879 kg m−2 h−1) at one solar irradiation. In addition, the using of green solar energy as evaporation driving force could accelerate the transferring of iodine ions containing water through CMPs derived solar evaporator, which in turn improved the mass transfer. More importantly, the results of interfacial evaporation experiments on aqueous solutions containing iodine ions (0.2 mmol L−1) revealed that the concentration of iodine ions in the collected condensate was only 0.0027 mmol L−1, which decreased nearly three orders of magnitudes of initial concentration. Also, the iodine ions in water were almost completely enriched by the interfacial evaporator CCMP-1. In view of the fact of big challenge of removal of radioactive iodine ions from wastewater, remaining in current technologies, the findings of this study might provide a simple and efficient solution for treatment of radioactive pollutions contained in wastewater using green solar energy as deriving force via the SSG method. [ABSTRACT FROM AUTHOR]

The sustainable supply of freshwater resources is facing serious challenges due to the frequent occurrence of severe global weather, increasing environmental pollution and continuous population growth. Solar-powered interfacial evaporation systems for wastewater treatment and desalination are considered a hopeful freshwater acquisition strategy to solve water scarcity and energy crisis. Aerogel materials can promote water transmission and evaporation due to their porous structure and tunable surface wettability. In recent years, solar clean water technology based on aerogel has become a current research hotspot result from its advantages, for example high evaporation efficiency and simple preparation method. In this article, the study progress of aerogel materials for solar interface evaporation field is systematically presented. Three main sections are discussed: photothermal conversion materials, interface evaporator and applications. Eventually, the problems faced by the current solar interface evaporation technology in the development process are analyzed, and corresponding countermeasures are proposed. • The advance of aerogel based solar energy interfacial evaporators is reviewed. • Introduced the characteristics of different photothermal materials • The application of photothermal materials in aerogel interfacial evaporators is introduced. • Introduced the application progress of different types of interface evaporators • The multifunctional application of aerogel based interfacial evaporator was introduced. [ABSTRACT FROM AUTHOR]

Solar interfacial evaporation is a promising method for solving the global shortage of fresh water. While 2D evaporators can efficiently localize solar-converted heat at the thin layer of the water-air interface, 3D solar evaporators can maximize energy reutilization while maintaining effective mass transport ability, few studies are conducted to explore the effect of gradient porosity on evaporation performance. In this study, a multifield assisted strategy based on a gradient 3D structure with high tortuosity is proposed, which creates a thermal field environment for efficient evaporation through high absorption of sunlight and excellent photothermal conversion and uses the gradient structure to optimize the internal pressure field to enhance water evaporation and transport. This hierarchically nanostructured solar absorber, with porosity inhomogeneity-induced pressure gradient and optimized temperature management, is a valuable design idea for manufacturing a more efficient 3D solar evaporator in the field of seawater desalination. Owing to the understanding of optimizing the dimension by various simulation parameters, the evaporation efficiencies of such structures are found to be 165.7%, suppressing the most evaporator. Moreover, it can provide new ideas and references for the fields of mass transfer and thermal management., (© 2023 Wiley-VCH GmbH.)

Solar-driven interfacial evaporation technology, a potential method of solving freshwater scarcity without any fossil energy consumption and environmental impact, is limited by its core component of photothermal materials. Herein, we fabricated a cellulose/PVA hydrogel with interconnected pores structure via an in-situ method to improve its working capacity in seawater desalination and wastewater purification. The results show that adding hydroxypropyl cellulose and changing light absorbers (CNTs and Chinese ink) can efficiently regulate the evaporation enthalpy to accelerate the evaporation. Integrating the interconnected pores structure with an indirect water supply can achieve confinement capillarity, i.e., upward water transportation along the inner surface of the porous hydrogel instead of being full of all pores, thus obtaining a sharp increase in evaporation interface. Compared to Chinese ink, CNTs particles exhibit an obvious promotion to the mechanical properties and evaporation capacity. Eventually, the evaporation rate of the hydrogel containing CNTs with optimized structure can reach 3.16 kg m−2 h−1 under 1 sun. Besides, the as-prepared hydrogel has impressive performance in working stability and self-cleaning capacity under harsh environmental conditions, such as high-concentration brine, strong acid, and alkaline solution. The regulation strategy will arouse new inspiration from numerous researchers about designing and manufacturing high-performance solar-driven evaporators. [Display omitted] • Cellulose/PVA hydrogel with confinement capillarity for soalr evaporation was prepared by in-situ method. • Hydratability and evaporation enthalpy were regulated by controlling the composition and structure of the polymer network. • Integrating the indirect water supply and the interconnected pores structure enable the confinement capillarity effect. • The cellulose/PVA hydrogel exhibits excellent evaporation capacity (3.16 kg m-2 h-1) and good salt-resistant ability. [ABSTRACT FROM AUTHOR]

Solar-driven interfacial evaporation (SIE) has attracted extensive research for seawater desalination in recent years. Great progress has been achieved in enhancing evaporation rate and salt tolerance in open systems, but there are few studies about SIE in closed systems, let alone the differences between open and closed systems. Here, we show the differences between open and closed SIE systems using solar evaporators with tunable water transport rate. There are great differences in water evaporation rate, salt deposition behavior, surface temperature of the photothermal sheet, ambient temperature and ambient relative humidity between open and closed systems. With increasing water transport rate, the evaporation rate shows different trend in open and closed systems due to their different demand for water transport. The optimal SIE condition in the open system is inconsistent with that in the closed system. High evaporation rate can be achieved at proper water transport rate, as it determines the salt deposition area and heat loss. Also, the optimal water transport rate depends on the brine concentration. The differences between open and closed systems were further demonstrated by the outdoor practical SIE test. Thus, for harvesting more clean water, future SIE studies should focus more on closed systems. [Display omitted] • The differences between open and closed SIE systems were explored • The SIE performance of solar evaporators should be optimized in the closed system • Solar evaporators exhibit better salt tolerance in closed system [ABSTRACT FROM AUTHOR]

Solar interfacial evaporation is a potential technology to produce clean water due to its simplicity and being driven by renewable clean energy, but it still requires further development to break through the bottleneck of removing volatile organic compounds (VOCs), especially in wastewater treatment. Herein, we proposed a dual-functional hydrogel evaporator that coupled solar interfacial evaporation with Fenton reaction to simultaneously remove VOCs and non-volatile pollutants from water with low energy consumption and high efficiency. The evaporator was composed with β-FeOOH and polydopamine (PDA) on an electrospun nanofibrous hydrogel. Arising from the PDA with excellent photothermal properties, the evaporator revealed a high light absorption characteristics (∼90%) and photothermal efficiency (83.4%), which ensured a favorable evaporation rate of 1.70 kg m-2 h-1 under one solar irradiation. More importantly, benefited from the coupled Fenton reaction, the VOCs removal rate of β-FeOOH@PDA/polyvinyl alcohol nanofibrous hydrogel (β-FeOOH@PPNH) reached 95.8%, which was 6.5 times than that of sole solar interfacial evaporation (14.8%). In addition, the evaporator exhibited an outstanding non-volatile pollutant removal capability and stable removal performance for organic pollutants over a long period of operation. The prepared β-FeOOH@PPNH evaporator provides a promising idea for simultaneous removal of non-volatile pollutants and volatile pollutants performance in long-term water purification. [Display omitted] • Efficient and synchronous long-term removal of non-volatile and volatile pollutants. • Overcome the defect of treating VOCs wastewater in solar interfacial evaporation. • Avoid secondary pollution to the environment caused by enriched organics in water. • Durable dual-functional nanofibrous hydrogels for a variety of water purification. [ABSTRACT FROM AUTHOR]

In this Article , a cotton fabric evaporator with superhydrophobic-hydrophobic-hydrophilic-superhydrophilic wettability gradient was prepared, which can limit excess water from entering the evaporator to reduce heat leakage. This evaporator exhibited high evaporation rates for saline water with different salt concentrations, and it was used to purify colored wastewater and heavy-metal wastewater. The collected condensate water can be directly consumed by humans after water quality testing. This strategy provided new insights for the development of low heat leakage evaporators and reliable water purification technologies. [Display omitted] • A cotton fabric evaporator with wettability gradient was fabricated. • The wettability gradient hindered excess water entering the evaporator. • Evaporation rate of 1.540 kg m -2 h -1 achieved with an energy conversion efficiency of 93.7%. • The evaporator exhibited excellent solar desalination and wastewater purification capacity. Harvesting light energy and converting it to heat as terminal energy by black photothermal sheets as evaporator is a novel strategy to attain fresh water. Although immense progress has been achieved in terms of the improvement of the evaporation rate and energy efficiency, it is still challenging to limit excessive water from entering the evaporator to eliminate the energy loss. Herein, a novel cotton fabric evaporator with a superhydrophobic-hydrophobic-hydrophilic-superhydrophilic wettability gradient (CFE-WG) was constructed by the layer-by-layer self-assembly of carbon nanotubes (CNTs), followed by separate modification with polyvinyl alcohol (PVA) and polydimethylsiloxane (PDMS). The wettability gradient in the thickness direction of CFE-WG permitted the slow transfer of water from the superhydrophilic side to the hydrophilic area and ultimately trapped the water at the hydrophilic/hydrophobic (water/air) evaporation interface, which avoiding the entry of excessive saline water inside the evaporator and maximally limiting thermal leakage. Under 1 sun irradiation, this CFE-WG exhibited a high vapor generation rate up to 1.54 kg m -2 h -1 , corresponding to an energy conversion efficiency of 93.7%. Notably, it could be used for desalination and wastewater treatment to collect fresh water that meets drinking requirements set by the WHO. This study provides a facile strategy to prepare a scalable evaporator for portable solar water purification, industrial solar-powered water treatment, and other advanced solar thermal applications. [ABSTRACT FROM AUTHOR]

• A simple breath figure method was first employed to fabricate double-layer evaporator. • The PC@PPy has advantages of low cost, simple and scalable manufacture process. • The PC@PPy-EPE shows excellent energy conversion efficiency of 93.57% under 1 sun irradiation. • The PC@PPy-EPE displays excellent salt-resistant performance even in 20 wt% NaCl. Solar interfacial evaporation (SIE) is one of the most prospective solar energy harvesting technologies for solving the scarcity of freshwater resources. Herein, we report a novel photothermal membrane polycarbonate (PC)@polypyrrole (PPy) (PC@PPy) adopting to breath figure method followed by surface chemistry modification, and assemble a double-layer solar interfacial evaporator consisting of PC@PPy photothermal membrane as the upper layer and plant fiber-wrapped expanded polyethylene (EPE) foam as the bottom layer for SIE. Due to the abundant porous structure and strong light absorption of the PC@PPy membrane, excellent insulation of the EPE sponge, the as-prepared PC@PPy-EPE evaporator exhibits a high evaporation of 1.78 kg m-2h−1 and photothermal conversion efficiency of 93.57%, and outstanding evaporation stability and resistance in 16% wt NaCl with an evaporation of 1.58 kg m-2h−1 under 1 sun irradiation. Moreover, the PC@PPy photothermal possess superior flexibility and strong mechanical properties. Coupling with cost-effective, environment-friendly, simple and easily scale-up breath figure preparation method, the PC@PPy-EPE generator has broad application prospects in SIE. [ABSTRACT FROM AUTHOR]