Evaporation Efficiency Research Articles

Highly Efficient Porous Glass Solar Water Evaporator

AbstractThe global water crisis, exacerbated by excessive use and pollution, has resulted in energy scarcity and threats. Solar desalination provides a sustainable fix, with researchers developing photothermal materials and designs to improve efficiency and sustainability. Glass materials, with their exceptional chemical stability, are suitable for extreme desalination in acidic and alkaline conditions. In this work, we have developed a porous glass evaporator (PGE) with exceptional water evaporation efficiency, achieved through a novel fabrication method that blends glass powders with soluble salts to create structure with continuous pores. The evaporator's microstructure comprises micrometer‐scale pores that form interconnected porous channels, facilitating efficient water transport and preventing salt deposition. Under one sun irradiation, the PGE exhibits superior solar evaporation performance in pure water, achieving a rate of 2.21 kg m−2 h−1, with an evaporation efficiency of 98%. In more complex media, such as seawater and methylene blue solution, the PGE also displays excellent evaporation capabilities, reaching rates of 2.08 and 2.47 kg m−2 h−1, respectively. Even after sustained alternation between acidic and alkaline treatments, the PGE retains an impressive evaporation rate of over 2.0 kg m−2 h−1, coupled with structural robustness, making it a promising candidate for practical applications in extreme environments.

Strategically Designed Uniform MOF-Derived Nanoporous Carbon Aerogel for Efficient Solar-Driven Desalination by Control of Hydrophilicity and Thermal Conductivity.

Desalination techniques using the photothermal effect hold significant potential for producing fresh water from saline or polluted sources due to their low energy consumption. In the case of commercialized carbon materials are related to heat loss resulting from high thermal conductivity, and metal particles still have trouble in commercialization or cost-effectiveness. This is because a photothermal desalination evaporator must simultaneously exhibit high water evaporation performance, excellent energy conversion efficiency, sufficient hydrophilicity, and low heat loss. In this work, developing an efficient in situ energy utilization technology that instant light to heat energy conversion system based on ZIF-8/agarose-derived carbon aerogels, achieved by controlling hydrophilicity, thermal conductivity, and light absorption properties is reported. The carbon aerogel demonstrates excellent performances of improved capillary force, structural stability, and cost-effectiveness. The designed carbon aerogel, with a high surface area (524 m2 g-1), adequate hydrophilicity, and low density (0.07g cm-3), is buoyant enough to float on the water. A water evaporation efficiency of 1.53kg m-2 h-1 under 1 sun and a light-to-heat conversion of 85% are achieved, along with effective salt blocking through the size-controlled uniform ZIF-8 nanoparticles and optimized composition with agarose.

Welding Pollen-Based Solar Evaporator for Clean Water Production.

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 1.86kg 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 (3.44MPa) 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.

Intercropping increases plant water availability and water use efficiency: A synthesis

Intercropping, involving the incorporation of annual crops with alternative crops or non-crop cash crops, has the potential to enhance water conservation and stabilize agroecosystems. However, few studies have comprehensively explored the effects of intercropping on water cycling. Here, we investigated the impacts of intercropping on five crucial water cycle processes (states): soil water content (SWC), runoff (RO), soil evaporation (E), leaf transpiration (LT), and water use efficiency (WUE). To this end, a meta-analysis was carried out utilizing a global dataset comprising 1285 paired observations from 64 publications. We found that intercropping reduced SWC (1.31 %), RO (29.17 %), and E (10.30 %), but increased LT (9.85 %) and WUE (29.46 %). The effects of intercropping on SWC, E, and RO did not exhibit significant fluctuations over the course of a year, but SWC initially decreased then increased in multi-year planting durations. Moreover, the intercropping effect was contingent upon climatic conditions (mean annual precipitation and temperature), soil characteristics (organic matter content, bulk density, and total nitrogen content), and agricultural practices (crop type, fertilization, and irrigation). We determined that resource complementarity, abiotic facilitation, and biotic feedback mechanisms may underlie the effect of intercropping on the water cycle. This research underscores the potential of using intercropping to improve plant water usage and the sustainability and productivity of cropping systems.

Highly efficient solar steam evaporation via elastic polymer covalent organic frameworks monolith

Three-dimensional solar steam evaporators with efficient water purification performance have received increasing attention recently. Herein, elastic polymer covalent organic frameworks (PP-PEG) containing PEG chains with intriguing adaptability to guests are prepared by forming porphyrin rings. PP-PEG foams demonstrate full spectrum absorbance and excellent photothermal conversion properties. Through well-designed thermal management and optimization of the hydrophilicity and PEG chain length, we obtain a highly efficient solar evaporator with an evaporation rate of 4.89 kg m−2 h−1 under 1 sun in self-contained mode. The optimized solar evaporation rate is increased to 18.88 kg m−2 h−1 under 1 sun with a facile truncated cone reflector, exceeding all known solar steam evaporators. This innovative design holds immense promise for desalination and water purification owing to its simple preparation, high efficiency and durability.

Simultaneous realization of efficient solar evaporation and electricity collection through dual regulation of chemical composition and pore channels

The solar-driven interfacial evaporation is a recently developed zero-energy technology for seawater desalination. However, the low evaporation rate poses a significant obstacle to its industrial application, and the collection of streaming potential formed during the evaporation process remains challenging. In this paper, we constructed a solar evaporator capable of simultaneously achieving efficient solar evaporation and electricity collection. Specifically, a double network structure hydrogel comprising polyvinyl alcohol (PVA) and TEMPO-oxidized cellulose nanoparticles nanofibers (TOCNFs) was fabricated using ice templating, with the addition of sodium lignosulfonate (SLS) to further modulate water distribution within the network. The incorporation of carbon nanotubes (CNTs) enabled the achievement of a PVA/TOCNFs/SLS (PTFS) gel-based solar evaporator. The strong electronegativity carried by the TOCNFs enhances the electrostatic repulsion in the PVA-TOCNFs network, thus improving the mechanical properties of PTFS evaporator. The introduction of SLS, which contains abundant sulfonate groups, provides certain antibacterial properties to PTFS evaporator. Due to the presence of numerous hydrophilic groups, both TOCNFs and SLS can form weak hydrogen bonds with water. Through the synergistic effect of TOCNFs and SLS, the latent heat of water in PTFS evaporator is reduced to 924 kJ kg−1, enabling an evaporation rate of 3.70 kg m−2h−1 under 1 sun irradiation. Owing to the smaller pore size relative to the Debye radius and the presence of electronegative functional groups within the pores of PTFS evaporators, an overlapping bilayer is formed when water flows through, resulting in an open-circuit voltage increase of up to 270 mV. The integration of high-efficiency solar evaporation with streaming potential collection presents a novel avenue for enhancing the utilization of solar energy.

Self‑supporting magnetic nanoporous silver-nickel films with broadband light absorption for efficient interfacial solar steam generation

Interfacial solar steam generation (SSG) is a promising eco-friendly strategy for freshwater production to address the global water crisis, which depends upon high-efficiency and low-cost photothermal materials. Herein, a series of self-supporting magnetic nanoporous silver-nickel (NP-AgNi) films were fabricated by one-step dealloying of specially designed Al99AgxNi1-x (x = 0.3, 0.5, 0.7) precursors. Both in-situ and ex-situ characterizations were performed to unveil the phase/structure evolution during dealloying of AlAgNi. Specially, the obtained NP-AgNi films with high porosity (>89 %) and tunable magnetic properties exhibit a unique three-dimensional bicontinuous ligament-channel Ag network with embedded Ni microparticles, as well as good hydrophilicity. Combined with the synergistic light absorption of the bimetal Ag and Ni, the NP-AgNi films exhibit good broadband absorption over the 200–2500 nm wavelength. More importantly, the NP-AgNi films show excellent SSG performance (evaporation efficiency over 89 %, evaporation rate ≥ 1.42 kg·m−2·h−1 and good cycling stability) under one sun irradiation. Additionally, the NP-AgNi films show outstanding seawater desalination and dye wastewater purification capability. This work provides an inspiration for the design and fabrication of multi-functional metal-based photothermal films in solar water treatment.

Sustainable solar-powered seawater desalination enabled by phosphorene-decorated watermelon-like phase-change microcapsules

Solar-powered interfacial evaporation is considered as an emerging innovative technology for seawater desalination; however, it suffers from insufficient evaporation efficiency under intermittent solar irradiation. Aiming at realizing sustainable solar-powered seawater desalination for clean water production, we have designed a new type of watermelon-like phase-change microcapsules as a photothermal absorbent material for a solar interfacial evaporator. This type of phase-change microcapsules was prepared through rational layer-by-layer microencapsulation with a ZrO2 nanoparticle-containing n-docosane core as a phase-change material (PCM) for solar photothermal harvest and prompt thermal response, a ZrO2 shell for the leakage prevention of the molten n-docosane core, and a polydopamine coating layer together with its surface-decorated phosphorene nanoflakes for high-efficient sunlight absorption and fast water transportation. The resultant microcapsules are featured by a watermelon-like microstructure as confirmed by transmission electron and scanning electron microscopy. They also exhibit a high light absorption efficiency of 84.95 %, a high latent heat capacity of 146.2 J g−1, and good wettability. Equipped with the watermelon-like phase-change microcapsules, the developed solar interfacial evaporator obtained an evaporation rate of 3.09 kg m−2 h−1 under one-sun illumination for seawater desalination. The PCM core within the microcapsules can store solar photothermal energy as latent heat under sufficient solar irradiation and then release it under evaporation conditions without sunlight illumination, thus enhancing the water evaporation efficiency. This enables the developed evaporator to increase its total evaporation mass by 31.5 % on a cloudy day in comparison with the conversional solar evaporator without a PCM, indicating a remarkable enhancement in the evaporation performance under intermittent solar irradiation. The developed solar interfacial evaporator exhibits great potential for application in sustainable solar-powered seawater desalination.

One-step development of photothermal omniphobic membrane for vacuum membrane distillation towards sustainable water desalination using solar energy

Nowadays, development of photothermal omniphobic membranes (POMs) for water desalination using solar energy has gained considerable attention to face water and energy challenges in a sustainable way. Scientists have been developing POM via different techniques based on photothermal component loading and surface energy reduction, all of which suffer from multi-step processes. Obviously, researchers and especially industrial developers aspire to one-step techniques that make the production process highly accelerated and economical. In this study, a one-step technique to develop POMs is demonstrate, using which the omniphobic and photothermal properties are simultaneously imparted to the membrane through being integrated with the membrane fabrication process. The technique works based on elaborate design of membrane surface chemistry and roughness via electrospinning of poly(vinylidene fluoride) (PVDF)/poly(1H,1H,2H,2H-perfluorooctyl acrylate) (PPFOA) blend solution containing carbon black nanoparticles (CB NPs). Optimum concentrations for PPFOA and CB NPs with respect to the PVDF weight were obtained as 60 and 15 wt%, respectively. The developed membrane exhibited permeate flux and salt rejection as high as 2.94 kg/m2·h and > 98 %, respectively, under one sun radiation. Evaporation rate and efficiency of the developed membrane were calculated as 1.49 kg/m2.h and 83.5 %, respectively. The membrane exhibited stable long-term performance for 600 min in contact with the sodium dodecyl sulfate (0.8 mM)-containing NaCl aqueous solution (3.5 wt%). Besides single-step implementation, the introduced technique benefits from endowing the entire membrane structure with omniphobic and photothermal properties not only the membrane surface. This can drastically improve the membrane performance and life time.

Design and optimization of plasmonic metal nanoantennas on a glass substrate for efficient solar-driven evaporation of seawater: an optical and numerical simulation approach

Design and optimization of plasmonic metal nanoantennas on a glass substrate for efficient solar-driven evaporation of seawater: an optical and numerical simulation approach

A Gradient Photothermal Hydrogel with Carbon-Dots Deposited Molybdenum Disulfide Nanoflowers as Photothermal Centers for Efficient Solar-Driven Water Evaporation and Treatment

Given the urgency of water pollution and freshwater scarcity, the pursuit of efficient and clean desalination techniques has gained prominence. In this study, a multi-defective molybdenum disulfide nanoflower was synthesized within a carbon-dots solution environment, named CDs/MoS2, exhibiting exceptional photothermal and catalytic properties. Relying on the excellent photothermal properties, antibacterial rates of up to 94% and 99% against Staphylococcus aureus and Escherichia coli. Additionally, the CDs/MoS2 nanoflowers exhibited a remarkable removal efficiency of 91% for high concentrations of methylene blue (MB) through photodegradation. A gradient photothermal composite hydrogel (CDs/MoS2@PVA Hydrogel) was designed to serve as a solar-driven clean water generator to isolate drinking water from various non-potable water. The gradient hydrogel effectively enhanced solar energy absorption through light trapping, creating dispersed hot spots to capture and activate water molecules. As a result, it achieved a high evaporation rate of 1.49 kg m-2 h-1 at a solar radiation of 1 kW m-2, with an impressive solar-to-vapor conversion efficiency of 92.5%. The hydrogel was successfully employed in diverse water treatment applications, including desalination, anti-bacteria and removal of organic contaminants from water. This study presents an innovative approach to developing novel solar vapor materials for water purification purposes.

Surface patterned polyvinyl alcohol/CNT hydrogels for sustained solar powered high concentration brine desalination and salt harvesting

Solar-driven interfacial evaporation is an attractive way to achieve water purification. However, high water evaporation rates often result in the precipitation of salt crystals on the surface of the evaporator leading to decay of the evaporation efficiency over time, which makes it difficult to balance high water evaporation rates with salt resistance. Herein, an anisotropic polyvinyl alcohol/CNT hydrogel is constructed by directional freezing and surface patterning. The polymer backbone formed by the polyvinyl alcohol chains interacts with the water clusters to reduce the evaporation enthalpy of water and the absorbed water can be released by squeezing the hydrogels due to the micron-sized vertically aligned pores. More importantly, by designing the structure of the hydrogels surface, the gas–liquid interface of the evaporators can be increased while the growth direction of the salt crystals can be controlled. As a result, the water evaporation rate can be increased from 3.26 kg m-2h−1 to 3.69 kg m-2h−1 under one sun irradiation through surface patterning. After 50 h of continuous operation in 10 wt% NaCl solution under one sun irradiation, the water evaporation rate gradually increases and a large amount of salt collection is collected, which proves its satisfactory salt resistance.

Superhydrophilic and porous carbon nanofiber membrane for high performance solar-driven interfacial evaporator

In light of the mounting global water crisis, solar interfacial evaporation has emerged as a pivotal technology for the advancement of water resource management. One of the most effective methods for enhancing the evaporation rate of solar evaporators is to optimize their utilization of light. In this study, a superhydrophilic Cu/C porous fiber evaporator was prepared using a multi-fluid electrospinning technology and a thermal treatment method. This evaporator exhibits excellent evaporation performance under the effect of Cu NPs, carbon fiber and a porous structure. The results demonstrated that the evaporation rate of the evaporator could reach 1.41 kg m−2 h−1 under one sunlight irradiation (Evaporation efficiency of 94.6 %). In addition, for wastewater containing organic dyes, acidic and alkaline, the evaporator has a significant cleaning effect. This high photothermal conversion efficiency suggests a promising avenue for the utilization of solar energy in water purification.

3D reconfigurable hydroxylated carbon nanotubes-based water evaporators with long-distance transportation for continuous vapor generation

Utilizing solar-thermal power for water purification through interfacial solar steam generation represents an environmentally friendly approach to secure a clean water source. However, it is still challenging to simultaneously overcome short transport distances, low transport rates, and unsatisfactory solar-thermal energy conversion efficiency, as well as the salt accumulation problem. In this work, three-dimensional (3D) reconfigurable water evaporators are developed based on commercial fabric strings and hydroxylated carbon nanotubes. The specifically designed 3D architecture enables the fabric strings to have a long water transport distance and localized focusing of solar light that benefits the fabrication of 3D evaporators and water isolation with low heat loss. Besides, the hydroxylated carbon nanotubes with strong hydrophilicity as well as their inherent black color show high solar-heat conversion efficiency. A high evaporation rate of 3.234kg m-2h−1 is found and a solar-to-vapor efficiency of 123.21 % is also achieved by using a vertical evaporation structure due to the enlarged surface area allowing absorption of heat from the environment. Meanwhile, the accumulated salts do not block the water transport pathway and they can be easily removed in high-salinity water evaporation by employing the assembled rotating evaporator. The results suggest that the fabric rope is a good platform for exploring highly efficient evaporation structures. Combined with hydroxylated carbon nanotubes, as-designed 3D reconfigurable evaporators are promising for efficient freshwater generation.

A 3D-Printed Bionic Membrane with Autonomously Passive Unidirectional Liquid Transfer Capability for Water Condensation, Collection, and Purification.

Interfacial solar vapor generation is a promising technology for alleviating the current global water crisis, and the evaporation rate and efficiency have approached the theoretical limit. In a practical interfacial evaporation water purification system, the collection rate of purified water is typically lower than the evaporation rate. Passive collection devices based on gravity are susceptible to environmental influences and exhibit low collection efficiency, while active collection devices consuming external energy suffer from complex device systems and extra energy consumption. Given that both collection devices are nonselective and unable to distinguish contaminants mixed in the vapor, bionic membranes with autonomously passive and unidirectional water transfer capacity are developed through 3D printing for efficient water collection. More importantly, the bionic membranes are capable of high-speed water transportation without the need for external energy or gravity drive and liquid-selective transportation for separating oily pollutants from the collected products. The directional transport property facilitates the modular assembly of the bionic membrane, extending its application to practical large-scale solar-driven seawater desalination systems.

Innovative solar-assisted direct contact membrane distillation system: Dynamic modeling and performance analysis

The study presents an innovative solar-assisted dual-tank direct contact membrane distillation (DCMD) system designed to enhance the operational stability and efficiency of solar-powered desalination. The proposed system integrates a dual thermal storage tank configuration, allowing for continuous operation by alternating between two tanks that store pre-heated water, thereby mitigating the impact of solar energy fluctuations. The dynamic modeling approach used in this study predicts the system's performance under varying solar conditions, focusing on key parameters such as permeate flux, evaporation efficiency, and specific thermal energy consumption. The simulation results show that the system achieves an average permeate flux of 14.4 L/h m² and a thermal efficiency of 53.3 % at a hot water temperature of 60 °C, with a corresponding average specific thermal energy consumption of 1567 kWh/m³. These findings highlight a substantial improvement in both thermal efficiency and water production compared to conventional single-tank systems.The dual-tank DCMD system is particularly suited for deployment in remote or arid regions where stable and efficient freshwater production is critical. This research provides a comprehensive analysis of a novel solar-assisted desalination technology, contributing to the advancement of sustainable water resources management by providing a reliable and scalable solution that can maintain high operational efficiency even in remote areas with variable solar conditions.

Honeycomb-like Microthermal Traps on a Photothermal Surface for Highly Efficient Solar Evaporation.

Solar evaporation is an ecofriendly and practical method for seawater desalination. The photothermal layer, which absorbs solar energy and converts it to thermal energy, plays a crucial role in enhancing the efficiency of the evaporator. However, structural design methods for photothermal layers are often complex and energy-intensive. This work reports a simple and efficient strategy for fabricating a necklace-like beaded nanofiber self-organized honeycomb-structured photothermal material. The honeycomb-like cavities form numerous microscale thermal traps, achieving thermal localization while maintaining high energy utilization efficiency, which not only increases light absorption but also facilitates the diffusion and escape of steam. Besides, the hydrophobic honeycomb layer separates the photothermal layer and the interface water, which reduces considerable heat conduction loss and achieves an effective antisalting performance. These functional features endow the evaporator with an evaporation efficiency of 92.9%, and the evaporation rate reaches 2.11 kg m-2 h-1 at 1 sun irradiance, demonstrating its great potential for practical solar-driven seawater desalination under natural sunlight.

Dynamic Water Microskin Induced by Photothermally Responsive Interpenetrating Hydrogel Networks for High‐Performance Light‐Tracking Water Evaporation

AbstractSolar‐driven interfacial water evaporation is attracting increasing attention as a promising environmentally‐friendly solution to freshwater scarcity. It has been proven that a thin water layer on photothermal materials can prevent solar energy from invalidly heating the excess water to enhance the evaporation rate. However, the current water layers are usually formed on inelastic materials via confined capillarity, which are static and uncontrollable. Herein, we propose a flexible hydrogel‐based photothermal conversion material with thermal responsiveness by facile frontal polymerization, which can generate a unique dynamic water microskin (DWMS) during the solar evaporation process. The copolymerized hydrogel, introduced by the second polymeric poly(vinyl alcohol) network and thermally responsive poly(N‐isopropylacrylamide) (PNIPAM), exhibits reinforced mechanical strength and photothermally triggers reversible shrinking/swelling cycles that enable a thin water layer (≈32 µm) to balance the feedwater supply and photothermic energy input dynamically. As a result, a stable superior vaporization rate of 8.7 kg m−2 h−1 is achieved based on a cylindrical hydrogel with 6 cm height under 1 sun. Moreover, the simultaneous responsive bending allows efficient omnidirectional solar evaporation by light‐tracking to ensure maximum perpendicular solar absorption, which provides an alternative strategy for durable high‐efficiency solar evaporators for effective thermal management and solar utilization.

Experimental study and simulation of a solid desiccant cooling system installed in northern Algeria

An experimental investigation of a solid desiccant cooling system for a research laboratory on the Algerian coast has been carried out. The system utilized flat-plate solar collectors for regeneration and was evaluated through a combination of individual component characterization, system modeling (using TRNSYS), and experimental validation. The results obtained have been validated and show that the efficiency of the rotary heat exchanger reached 65 %, the evaporative humidifier efficiency reached 94 %, and the desiccant wheel achieved efficiencies of 73 % on the process side and 66 % on the regeneration side. This translates to a significant dehumidification effect, reducing absolute humidity in the treated air by 9 g/kg, for the supply air temperature effectively maintained at a comfortable 24 °C. The close agreement between the simulated and experimental COP values (1.13 and 1.08, respectively) validates the chosen approach and confirms the potential of this technology for energy-efficient building cooling in the hot and humid Mediterranean climate of northern Algeria.

Impact of Trichoderma spiralis Treatment on the Photothermal Water Evaporation Capacity of Poplar

In recent years, research on interfacial photothermal water evaporation has been thriving. Due to its inherent porosity, exceptional hydrophilicity, and renewable characteristics, wood has garnered significant attention as a material for interfacial photothermal evaporation absorbers. In order to enhance the cellular channels of poplar and improve its water migration capacity, Trichoderma spiralis was selected to inoculate and culture poplar specimens from different sections for 3, 5, and 7 weeks. Simultaneously, a solar radiation intensity of 1 kW·m⁻2 was simulated to perform photothermal evaporation tests on the specimens. This validated the water migration capabilities of different sections of poplar treated with Trichoderma spiralis under light and heat exposure. The characteristic changes were analyzed using electron microscope scanning, infrared spectrum analysis, X-ray photoelectron spectroscopy analysis, surface infiltration performance, and automatic specific surface porosity. The results suggested that the moderate degradation of cellulose and hemicellulose in poplar by Trichoderma spiralis could dredge the cell channels and improve the permeability of poplar, particularly with regard to lateral permeability. The maximum photothermal evaporation rate of the poplar specimen reached 1.18 kg m⁻2 h⁻1, while the evaporation efficiency increased to 72.2%.