Water Evaporation System Research Articles

Transforming waste polystyrene foam to carbon on zeolite for efficient solar water desalination

Solar-driven water evaporation was well-proven to be a sustainable technique for seawater desalination by using renewable energy. In this technology, carbon material is preferably chosen as a photothermal conversion material due to its excellent stability and corrosion resistance. However, the applicability of carbon-based materials was constrained by their poor mechanical strength and the high cost. In this paper, carbon coated sands and zeolites were prepared by using waste polystyrene foam (white pollution) as carbon source and this waste utilization method greatly reduces material costs. The solar-driven water evaporation device was fabricated by confining these carbon-coated composites in the PVA hydrogel. Owing to the superior light absorption (over 96 %) and good hydrophilicity for water transfer, the carbon-coated sand and zeolite exhibited maximum evaporation rate of 1.51 and 1.24 kg m−2h−1 under 1 sun illumination, respectively. In outdoor test, the maximum water collection rate was 0.92 kg m−2 h−1. It is possible to create an effective and environmentally beneficial solar interfacial water evaporation system with this approach.

Continuous high-efficient water-electricity cogeneration over a hybrid solar-driven water evaporation system and the working mechanism

Continuous high-efficient water-electricity cogeneration over a hybrid solar-driven water evaporation system and the working mechanism

Water-flow-induced high-efficiency solar vapor generation and electricity collection

The interface photothermal evaporator still face challenges such as unstable operation, low evaporation efficiency, and insufficient energy utilization, particularly in high-concentration saltwater environments. This study proposes integrating a flow-induced power generation device within a photothermal-driven interface water evaporation system to address these issues. By leveraging the negative charge of carbon nanoparticles, a dual-electrode microchannel structure was optimized to establish an in-plane potential difference along the water transport path. The performance of the synchronized evaporation-flow-induced power generation system, with the carbon nanoparticle fabric as the core component, was thoroughly investigated, including its photothermal interface evaporation and power generation capabilities. Additionally, the controllability of the moisture content and water supply rate of the evaporation interface was achieved by adjusting the contact angle between the carbon nanoparticle fabric and bulk water, as well as the width of the water supply non-woven fabric. The synchronized evaporation-power generation system achieved an interface water evaporation rate of 1.44 kg m−2 h−1 and an output power density of 0.3 mW m−2 under 1 sun illumination (at a solar flux of q = 1 kW m−2). This study successfully obtained additional electrical energy output while prioritizing the evaporation rate, providing new insights for maximizing the energy efficiency of interfacial photothermal evaporation systems.

In Situ MXene Anchored Structure for Highly Durable Solar Steam Generation.

As a promising fresh water harvesting technology, interfacial solar steam generation has attracted growing interest. Efficient solar absorption and long-term operational performance are critical requirements of this technology. However, developing robust evaporators to promote practical applications under extreme conditions is still a grand challenge. Herein, we propose a light-assisted strategy to in situ prepare a Ti3C2Tx MXene anchored structure (MXAS) for enhanced solar evaporation with superior mechanical properties (compressive strength of 78.47 MPa, which can withstand a pressure of 3.92 × 106 times its own weight). Light irradiation enlarges the interlayer spacing of MXene and improves the solar absorption capability. Under one sun, the three-dimensional MXAS evaporator exhibits a steam generation rate of 2.48 kg m-2 h-1and an evaporation efficiency of 89.3%, and it demonstrates long-term durability when testing in seawater. This strategy provides valuable insights into the potential application of a high-performance water evaporation system.

Visualization of temperature distribution and flow behavior in water evaporation using water‐soluble spiropyran

AbstractUnderstanding the convection flows driven by the uneven temperature distribution in heated aqueous solutions is fascinating and meaningful both in fundamental and industrial aspects. Therefore, it is desirable to develop a simple and convenient method for real‐time tracking of surface temperature distribution and the solvent flow state. Herein, we designed and screened a water‐soluble spiropyran derivative (BS‐SP1) that contains benzothiazole and sulfonic acid groups. The BS‐SP1 molecule was found to exceptionally maintain the reversible photochromic characteristics in water, and then served as a photo‐responsive indicator for visualizing the temperature distribution and flow behavior on water surface with high resolution. This study provides feasible guidance on the dynamic self‐assembly and thermodynamics occurring in the water evaporation system and offers a practical tool for investigating these behaviors.

Low-Grade Waste Heat Enabled Over 80 L M-2 H-1 Interfacial Steam Generation Based on 3d Superhydrophilic Foam.

Clean water scarcity and energy shortage have become urgent global problems due to population growth and human industrial development. Low-grade waste heat (LGWH) is a widely available and ubiquitous byproduct of human activities worldwide, which could provide an effective power to address the fresh water crisis without additional energy consumption and carbon emissions. In this regard, three-dimensional (3D) superhydrophilic polyurethane/sodium alginate (PU/SA) foam and the LGWH driven interfacial water evaporation system have been developed, which can precipitate over 80 L m-2 h-1 steam generation from seawater and has favorable durability for purification of high salinity wastewater. The excellent water absorption ability, unobstructed water transport and uniform thin water layer formed on 3D skeletons of PU/SA foam ensure the strong heat exchange between LGWH and fluidic water. As a result, the heat-localized PU/SA foam enables the efficient energy utilization and ultrafast water evaporation once LGWH is introduced into PU/SA foam as heat flow. In addition, the precipitated salt on PU/SA foam can be easily removed by mechanical compression, and almost no decrease in water evaporation rate after salt precipitation and removal for many times. Meanwhile, the collected clean water has high ions rejection of 99.6% that meets the World Health Organization (WHO) standard of drinking water. Above all, this LGWH driven interfacial water evaporation system presents a promising and easily accessible solution for clean water production and water-salt separation without additional energy burden for our society. This article is protected by copyright. All rights reserved.

Three-Dimensional Mirror-Assisted and Concave Pyramid-Shaped Solar-Thermal Steam Generator for Highly Efficient and Stable Water Evaporation and Brine Desalination.

Although significant advances have been achieved in developing solar-driven water evaporators for seawater desalination, there is still room for simultaneously enhancing water evaporation efficiency, salt resistance, and utilization of solar energy. Herein, for the first time, we demonstrate a highly efficient three-dimensional (3D) mirror-assisted and concave pyramid-shaped solar-thermal water evaporation system for high-yield and long-term desalination of seawater and brine water, which consists of a 3D concave pyramid-shaped solar-thermal architecture on the basis of polypyrrole-coated nonwoven fabrics (PCNFs), a 3D mirror array, a self-floating polystyrene foam layer, and a tail-like PCNF for upward transport of water. The 3D concave pyramid-shaped solar-thermal architecture enables multiple solar light reflections to absorb more solar energy, while the 3D mirror-assisted solar light enhancement design can activate the solar-thermal energy conversion of the back side of the concave pyramid-shaped PCNF architecture to improve the solar-thermal energy conversion efficiency. Crucially, selective accumulation of the precipitated salts on the back side of the concave pyramid-shaped architecture is realized, ensuring a favorable salt-resistant feature. The 3D mirror-assisted and concave pyramid-shaped solar-driven water evaporation system achieves a record high water evaporation rate of 4.75 kg m-2 h-1 under 1-sun irradiation only and exhibits long-term desalination stability even when evaporating high-salinity brine waters, demonstrating its great applicability and reliability for high-yield solar-driven desalination of seawater and high-salinity brine water.

In vivo transepidermal water loss: Validation of a new multi-sensor open chamber water evaporation system Tewameter TM Hex.

Instrumentation technology for transepidermal water loss measurements has not been substantially modified since its introduction by Nilsson in 1977. Recent progress in sensor development allowed a new sensor arrangement using a matrix of 30 sensors. Raw measurement values are processed with spatial statistical analysis. We aimed to compare the new, multi-sensor probe (Tewameter TMHex) with the established Tewameter TM300 probe and to gain reference data for the new parameters of transepidermal energy loss and water vapor concentration on skin. Baseline measurements and repeated measurements on the volar forearm and assessment on eight different anatomical locations were performed on 24 healthy volunteers (both gender) with the TMHex and the TM300. A significant correlation (p<0.001; R-coefficient=0.9) between TMHex and the TM300 with a low coefficient of variance (CV) 11% for TMHex and 19% for TM300, could be assessed. The CV ranged between 7% (right inner upper arm) and 14% (palms). Average transepidermal heat loss ranged from 12W/m2 on the lower leg to 38.8W/m2 on the palm. The correlation between TMHex and TM300 along with the robustness of the measurements with the TMHex shows that the new probe for assessment of epidermal barrier function is comparable to the TM300. In most conditions, TMHex provides more accurate measurements than TM 300. New parameters open the field to studying skin's water and energy balance.

Perfluoroctylsilane grafted Ti3C2X-based hydrogel liquid marble for controlled movement, self-assembly, light-induced release, and water evaporation system

In this study, a stable and highly hydrophobic perfluoroctylsilane grafted Ti3C2X (PFMXene) possessing repeatable and stable photothermal behavior was applied for fabrication of liquid marble (LM) and hydrogel-based LM. PFMXene-based hydrogel LMs demonstrate floating ability and self-assembly on the water's surface. Moreover, controlled non-contact movement of hydrogel marble through the immersed tool in the water surface reached a speed up to 2 cm s−1. The structural character of the hydrogel matrix allows controlled light-induced disintegration of hydrogel liquid marble or application as a water evaporation system.

All-day working photovoltaic cooling system for simultaneous generation of water and electricity by latent heat recycling

The photovoltaic (PV) cooling system based on solar-driven interfacial water evaporation (SIWE) system can effectively reduce the temperature of PV panels and obtain fresh water, but it cannot work at night during which there is no heat source input. In this work, we proposed a novel SIWE-based PV cooling systems with optimized performance that can achieve all-day working. In this hybrid system, the heat generated by the PV panel is extracted as the form of vaporization latent heat through membrane distillation (MD). Then it transferred along with the condensation of water vapor and stored in Phase Change Material (PCM), which is used to achieve electric power generation by thermoelectric effect at night. The hybrid system can achieve an 19.5 % improvement of output power compared with that without cooling method. Additionally, a 1.55 kg m-2 h−1 fresh water output with a salt rejection rate more than 99.9 % are realized under 3-sun irradiation. At the same time, it can also achieve a peak power output of 6 W m−2 at night by the release of latent heat stored in PCM. This hybrid system may provide a new idea to broaden application scenarios of traditional SIWE-based PV cooling systems.

Improved Photo-Excited Carriers Transportation of WS2 -O-Doped-Graphene Heterostructures for Solar Steam Generation.

Two-dimensional (2D) transition metal dichalcogenides and graphene have revealed promising applications in optoelectronic and energy storage and conversion. However, there are rare reports of modifying the light-to-heat transformation via preparing their heterostructures for solar steam generation. In this work, commercial WS2 and sucrose are utilized as precursors to produce 2D WS2 -O-doped-graphene heterostructures (WS2 -O-graphene) for solar water evaporation. The WS2 -O-graphene evaporators demonstrate excellent average water evaporation rate (2.11kgm-2 h-1 ) and energy efficiency (82.2%), which are 1.3- and 1.2-fold higher than WS2 and O-doped graphene-based evaporators, respectively. Furthermore, for the real seawater with different pH values (pH 1 and 12) and rhodamine B pollutants, the WS2 -O-graphene evaporators show great average evaporation rates (≈2.08 and 2.09kgm-2 h-1 , respectively) for producing freshwater with an extremely low-grade of dye residual and nearly neutral pH values. More interestingly, due to the self-storage water ability of WS2 -O-graphene evaporators, water evaporation can be implemented without the presence of bulk water. As a result, the evaporation rate reaches 3.23kgm-2 h-1 , which is ≈1.5 times higher than the regular solar water evaporation system. This work provides a new approach for preparing 2D transition metal dichalcogenides and graphene heterostructures for efficient solar water evaporation.

Sponge-Based Aerogels for Efficient Solar Steam Generation

As a new type of solar energy utilization, solar photothermal water evaporation system has the characteristics of high photothermal conversion efficiency and green environmental protection, which can be widely used in the field of seawater desalination and sewage treatment. The bagasse carbonized by high-temperature pyrolysis was used as the photo-absorption material, and the polyurethane sponge-based aerogel photo-thermal conversion material was prepared with the double-network composite aerogel constructed by chitosan and polyurethane sponge as the substrate. It has good evaporation stability and is suitable for portable evaporation equipment. Moreover, when the carbonization temperature of carbonized bagasse was 500 °C and the addition amount was 1%, the evaporation performance of aerogel was the best. In the wavelength range of 200~2500 nm, its absorption rate can reach 98.2%, and its evaporation rate can reach 2.04 kg m−2h−1 at 1 kW m−2. In addition, the aerosol has good stability in general seawater and alkaline sewage, and is an effective method for solving seawater and sewage.

A reconfigurable and magnetically responsive assembly for dynamic solar steam generation

Interfacial solar vapor generation is a promising technique to efficiently get fresh water from seawater or effluent. However, for the traditional static evaporation models, further performance improvement has encountered bottlenecks due to the lack of dynamic management and self-regulation on the evolving water movement and phase change in the evaporation process. Here, a reconfigurable and magnetically responsive evaporator with conic arrays is developed through the controllable and reversible assembly of graphene wrapped Fe3O4 nanoparticles. Different from the traditional structure-rigid evaporation architecture, the deformable and dynamic assemblies could reconfigure themselves both at macroscopic and microscopic scales in response to the variable magnetic field. Thus, the internal water transportation and external vapor diffusion are greatly promoted simultaneously, leading to a 23% higher evaporation rate than that of static counterparts. Further, well-designed hierarchical assembly and dynamic evaporation system can boost the evaporation rate to a record high level of 5.9 kg m−2 h−1. This proof-of-concept work demonstrates a new direction for development of high performance water evaporation system with the ability of dynamic reconfiguration and reassembly.

Boosting Near-Infrared Photothermal Conversion by Intermolecular Interactions in Isomeric Cocrystals.

Organic cocrystal exhibits excellent photothermal conversion (PTC), but how the intermolecular interactions of cocrystals regulate the PTC is obscure. Here, two isomeric donor molecules (phenanthrene and anthracene) and two electron-withdrawing molecules (7,7,8,8,8-tetracyanodimethylquinone and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethane) are self-assembled into the four cocrystals (PTQ, PFQ, ATQ, and AFQ). By changing the molecular configuration of the donor and the electron-withdrawing ability of the acceptor, the intrinsic influencing factors of the intermolecular interaction on the PTC were explored. Under near-infrared laser (808 nm) irradiation, the PTC efficiencies of PTQ, PFQ, AFQ, and ATQ are 35.85, 44.74, 57.00, and 60.53%, respectively. Based on the single-crystal X-ray diffraction, ultrafast time-resolved transient absorption, and excited-state theoretical calculations, we found that the π-π stacking in ATQ and AFQ is conducive to promoting the near-infrared light-harvesting ability and the p-π interaction of cocrystals can regulate the nonradiative rotation of -C(C≡N)2 groups, resulting in a tunable near-infrared PTC via the isomeric cocrystals. Accordingly, the evaporation rate of the porous polyurethane-AFQ foam can reach 1.33 kg·m-2·h-1 in the simulated solar-driven water evaporation system. This work provides a strategy to boost the PTC by the intermolecular interactions of cocrystal materials.

Synergy of copper Selenide/MXenes composite with enhanced solar-driven water evaporation and seawater desalination

Despite significant of solar energy to power water evaporation in seawater desalination, the commercial application of this technology is limited by the poor light absorption and low photothermal conversion of existing photothermal materials. Herein, we report a simple method for solar-driven water evaporation using a device comprising Cu2-xSe/Nb2CTx nanocomposites supported by a glass microfiber membrane, which utilizes cotton thread as water transport pathway. The proposed device demonstrates excellent light absorption, water transportation, and thermal management. Benefiting from the strong synergetic photothermal effect of Cu2-xSe and Nb2CTx, the Cu2-xSe/Nb2CTx nanocomposites function as an efficient solar absorber with excellent photothermal conversion efficiency. The rough surface, low thermal conductivity and good hydrophilicity of glass microfiber membrane could maximize light capture, limit heat loss, and timely replenish water during the water evaporation process. When evaluated as a water evaporation system for outdoor seawater desalination, the system achieved a water evaporation of 12.60 kg·m−2 within 6 h. High fresh water generation rate is an important embodiment of high photothermal conversion efficiency. This study demonstrates a new route for designing solar desalination devices with high photothermal conversion properties.

Janus Co@C/NCNT photothermal membrane with multiple optical absorption for highly efficient solar water evaporation and wastewater purification

Solar-driven interfacial water evaporation has emerged as a promising approach for green and sustainable production of clean water to alleviate freshwater shortage, especially in remote and arid regions. However, limited photothermal conversion efficiency and poor water transport remain challenges to achieve highly efficient solar water evaporation. In this study, we propose a facile strategy to construct a novel Janus photothermal membrane by combining highly hydrophobic nitrogen-doped carbon nanotubes encapsulating cobalt nanoparticles (Co@C/NCNT) with a hydrophilic nylon membrane, which enables simultaneous realization of asymmetric surface wettability and multiple optical absorption pathways. The as-fabricated Janus Co@C/NCNT evaporator achieves a high solar water evaporation rate of 1.55 kg m−2 h−1 and an evaporation efficiency of 89.7% under one sun irradiation, which are well maintained after 10 cycles. Meanwhile, the Janus evaporator can be used for practical purification of various simulated wastewater, such as dyeing sewage and heavy metal wastewater, with high rejection efficiency and long-term stability. This Janus evaporator design provides an efficient, low-cost solar water evaporation system for potential water purification.

Electrochemical oxidation reconstructs graphene oxides on sponge for unprecedentedly high solar water evaporation

Although carbon nanomaterials are featured with low cost, outstanding solar-harvesting ability, ultrahigh stability and easy availability, their constructed evaporators still possess low evaporation rate so far under natural sunlight condition. Herein, we present an efficient electrochemical oxidation method to tailor chemical compositions and microstructures of graphene oxides (GO) upon porous melamine sponge (MS) for establishing ultrafast solar water evaporation system. Thanks to superior water activation property resulted from electrochemical oxidation, the afforded evaporation system is able to significantly reduce the water vaporization enthalpy, thereby exhibits a high evaporation rate of 3.47 kg m−2 h−1 with the solar-to-steam conversion efficiency of 97.4% under one-sun irradiation, which outweighs all of reported evaporators constructed by congeneric photothermal materials. Furthermore, this evaporation system displays outstanding mechanical performance and satisfactory tolerance to various harsh conditions. With long-term stability and good durability, this evaporation system provides a possibility of large-scale water purification with natural sunlight to meet the world ever-increasing demands for freshwater.

In‐Situ Self‐Assembled ZnO Foam Based on Graphene‐Like Ultrathin Nanosheets

AbstractIt is still a challenge to prepare 2D ultrathin ZnO in a simple method, especially for the in‐situ growth of 2D ultrathin ZnO on different substrates. Herein the ZnO foam with high specific surface area is successfully assembled in situ from graphene‐like ultrathin nanosheet on various substrates, including rigid fluoride doped tin oxide, Ni foam, and flexible indium tin oxide, carbon cloth, etc. The thickness of graphene‐like nanosheet is just ≈1.5 nm. The results reveal that the specific surface area of ZnO nanosheets is 90.7 m2 g−1. The high specific surface area of the hydrophilic ZnO foam and its in‐situ growth characteristic make it promising water channel in solar‐driven interfacial water evaporation system. By using a flexible carbon cloth/ZnO foam (C‐ZnO) Janus absorber, a high rate of water evaporation (2.4 kg m−2 h−1), which is 4.6 times higher than that of natural evaporation is demonstrated. This work provides a new method in the design of ZnO ultrathin nanosheets, what's more, the facile growth of the ZnO foam on various substrates make it possible for the application in optoelectronic devices.

Synergy of photothermal effect in integrated 0D natural melanin /2D reduced graphene oxide for effective solar steam generation and water purification

Solar steam generation has attracted widespread attention due to its ability to produce clean water without conventional energy consumption. However, how to obtain an environment-friendly, sustainable and powerful solar absorber system to generate efficient steam is still challenged. The melanin nanoparticles can dissipate 99.9% of the absorbed UV and visible without radiation, and their spherical nanostructure can effectively preserve heat. In addition, the oxygen and nitrogen related functional groups on their surfaces further reduce thermal conductivity. Thus, in this work, a new system of photothermal aerogel composed of sodium alginate (SA) with heterostructures absorber of natural 0D melanin nanoparticles (MNP) synergistic 2D reduced graphene oxide (rGO) was developed for solar-steam generation. By optimizing the porosity and preparation method, the alginate-based aerogels showed excellent absorption and lower reflection through the whole sunlight spectrum (200–2500 nm), super hydrophilicity, and lower thermal conductivity (0.05281 w k−1 T−1). The average evaporation rate and solar-steam generation efficiency reached 2.64 Kg m−2 h−1 and 93.9%, respectively, under one-sun illumination. Meanwhile, the solar driven evaporator exhibited excellent ability to purify realistic waters, such as seawater, ionized wastewater and dyeing sewage with ～ 100% removal rate. Significantly, this strategy offers a novel heterostructures absorber to construct a powerful solar water evaporation system for high-efficiency vapor generation and water purification in practical applications.

Molecular engineering of narrow bandgap porphyrin derivatives for highly efficient photothermal conversion

Organic dyes based on porphyrin derivatives have been widely reported to show promising application in dye-sensitized solar cells and organic solar cells due to their desired power conversion efficiency and extinction coefficient while their photothermal conversion performance is rarely reported, to date. Considering the design guideline of photothermal materials with wide near-infrared region absorption and large extinction coefficient, we designed and prepared a narrow bandgap donor-acceptor small molecule P(DPP)4 based on porphyrin and diketopyrrolopyrrole, which showed a photothermal efficiency of 73.2% under irradiation of 808 nm laser, due to its aggregation-induced radical and distinct nonradiative decay. Furthermore, in an interfacial-heating water evaporation system, P(DPP)4 exhibited an evaporation rate of 1.304 kg m−2 h−1 under 1 sun irradiation with a solar-energy-to-vapor efficiency of 90.6%, higher than most of the pure organic photothermal materials. This work provides a promising way for organic small molecules as solar absorbers with high solar-thermal conversion efficiency and reveals the great potential of organic semiconductors with aggregation-induced radical in photothermal materials.