Interfacial Solar Evaporation Research Articles

Cogeneration of Clean Water and Valuable Energy/Resources via Interfacial Solar Evaporation.

Water, covering over two-thirds of the Earth's surface, holds immense potential for generating clean water, sustainable energy, and metal resources, which are the cornerstones of modern society and future development. It is highly desired to produce these crucial elements through eco-friendly processes with minimal carbon footprints. Interfacial solar evaporation, which utilizes solar energy at the air-liquid interface to facilitate water vaporization and solute separation, offers a promising solution. In this review, we systematically report the recent progress of the cogeneration of clean water and energy/resources including electricity, hydrogen, and metal resources via interfacial solar evaporation. We first gain insight into the energy and mass transport for a typical interfacial solar evaporation system and reveal the residual energy and resources for achieving the cogeneration goal. Then, we summarize the recent advances in materials/device designs for efficient cogeneration. Finally, we discuss the existing challenges and potential opportunities for the further development of this field.

Bimetallic composite carbon fiber with persulfate mediation for intercepting volatile organic compounds during solar interfacial evaporation

Bimetallic composite carbon fiber with persulfate mediation for intercepting volatile organic compounds during solar interfacial evaporation

Root-based solar interfacial evaporation setup for efficient volumetric reduction of concentrated slurry waste

Although solar interfacial evaporation stands as a promising application for seawater desalination, it has been scarcely studied for volumetric reduction of particle-containing wastewater. Taking inspiration from trees, this work presents a novel approach of root-based solar-interfacial evaporation for accelerated drying of slurries. By varying the total surface area of the roots, the water conduction rate was maximized under different intensities of solar radiation. The optimal setup displayed a high evaporation rate of 1.15 kg/(m2h1) under 1 sun irradiation. Additionally, the evaporator dried the slurry to 75 wt% solid concentration at this high evaporation rate. The setup could remove water further till solid concentration above 90 wt% in a total 40-h duration. The decrease in slurry evaporation rates observed at higher solid concentration was attributed to the break-up of continuous water capillary bridges present between the particles in the slurries. Long duration evaporation experiments for over 100 h of continuous operation displayed 75 % evaporation efficiency, underlining the feasibility of this setup for long-term usage. Large-scale outdoor experiments, scaling to 625 cm2, exhibited high evaporation rates comparable to the smaller setups, confirming the feasibility of this setup for large-scale volumetric reduction.

Interfacial solar evaporation driven Cd removal from contaminated sediments

Solar-driven evaporative remediation (SDER) is an emerging low carbon technology suitable for both seawater desalination and wastewater treatment. Herein, we extend the application of the technique to sediment remediation for the first time by fabricating a functional evaporator (AC@HA-C) comprising cotton loaded with activated carbon and hydroxyapatite. This evaporator accelerated the extraction of Cadmium (Cd) from contaminated sediments. After 14 days of SDER, the overall Cd removal efficiency in sediments ranged between 49.2% and 65.7%. Moreover, cultivation of crops in SDER treated sediments showed an average reduction in Cd accumulation in cabbage by 74.1%. Comparing the AC@HA-C evaporator to other similar materials, life cycle assessment (LCA) showed a 94.0% reduction in environmental impacts and an 86.0% reduction in CO2 emissions. These results position AC@HA-C as a low-carbon and sustainable evaporator, offering a more environmentally friendly choice for sediment remediation.

MXene/Ag3PO4 modified PVDF composite membranes for efficient interfacial evaporation and photodegradation

Solar-powered interface evaporation is considered a promising technology to obtain freshwater from non-potable water by using sustainable solar energy. However, research on combining the photocatalytic effect with solar interfacial evaporation technology to go for photothermal conversion materials with full solar spectrum utilization for photothermal and photodegradation capabilities is still scarce. Due to the unique optical properties of MXene, a novel MXene/Ag3PO4-based membrane with synergistic photothermal and photocatalytic effects was developed from the perspective of practical applications such as water purification, photodegradation of organic dyes and antibacterial properties. In this paper, polyvinylidene fluoride (PVDF) and carbon black (CB) were used as the substrate, calcium carbonate (CaCO3) and hydrochloric acid (HCl) were selected as the pore-forming agent for hydrophilic modification, and MXene/Ag3PO4 serves as the photocatalyst. The prepared composite polyvinylidene fluoride membrane (PCC-MXene/Ag3PO4) with Schottky junction, possesses a rich pore structure, abundant water molecule transport channels, high light absorption ability, and low thermal conductivity, which lead to a good performance in solar interface evaporation, photodegradation and antibacterial. The superhydrophobicity and floatability of the nanosponges in water enable them to continuously pump water, which greatly promotes the dissolution of salt accumulation. With the help of porous nanosponges, PCC-MXene/Ag3PO4 exhibits excellent evaporation stability and salt resistance under 1 kW m−2 solar irradiation, as well as photodegradation of organic dyes. In addition, the PCC-MXene/Ag3PO4 membrane has the properties of self-buoyancy, electrical conductivity, and superior flexibility. Therefore, considering the simple preparation method and fine performances, the PCC-MXene/Ag3PO4 mixed membrane has great application potential in the study of interface evaporation, photodegradation of organic dyes, and antibacterial properties.

Polyhedral Oligomeric Sesquioxane Cross-Linked Chitosan-Based Multi-Effective Aerogel Preparation and Its Water-Driven Recovery Mechanism.

The use of environmentally friendly and non-toxic biomass-based interfacial solar water evaporators has been widely reported as a method for water purification in recent years. However, the poor stability of the water transport layer made from biomass materials and its susceptibility to deformation when exposed to harsh environments limit its practical application. To address this issue, water-driven recovery aerogel (PCS) was prepared by cross-linking epoxy-based polyhedral oligomeric silsesquioxane (EP-POSS) epoxy groups with chitosan (CS) amino groups. The results demonstrate that PCS exhibits excellent water-driven recovery performance, regaining its original volume within a very short time (1.9 s) after strong compression (ε > 80%). Moreover, PCS has a water absorption rate of 2.67 mm s-1 and exhibits an excellent water absorption capacity of 22.09 g g-1 even after ten cycles of absorption-removal. Furthermore, a photothermal evaporator (PCH) was prepared by loading the top layer with hydrothermally reacted tannins (HAs) and Zn2+ complexes. The results indicate that PCH achieves an impressive evaporation rate of 1.89 kg m-2 h-1 under one sun illumination. Additionally, due to the antimicrobial properties of Zn2+, PCH shows inhibitory effects against Staphylococcus aureus and Escherichia coli, thereby extending the application of solar water evaporators to include antimicrobial purification in natural waters.

Polyethersulfone-silica aerogel/ polypyrrole solar evaporation membrane for wastewater treatment and desalination

Solar interfacial evaporation utilizes a specific structure of the evaporator to confine the energy to the light absorbing layer, so that the water completes efficient evaporation on the surface of the structure. In this paper, polyethersulfone- silica aerogel/ polypyrrole solar evaporation membranes (PES-SiO2/PPy) with excellent photo-thermal conversion and efficient seawater desalination performance were prepared by loading PPy on polyethersulfone-silica aerogel ultrafiltration membranes (PES-SiO2) via in situ polymerization. With its stable and efficient thermal insulation performance and heat absorption ability, the temperature on the surface of the evaporation membrane was as high as 49.9 °C under 1 kW m−2 light intensity, and the maximum evaporation rate reached 1.86 kg m−2 h−1, with an evaporation efficiency of 97%. The evaporation membranes also have long-term stable evaporation performance. At an outdoor light intensity of 0.8 kW m−2, the evaporation rate of simulated seawater reached 1.87 kg m−2 h−1 with a high evaporation efficiency of 131.6%, which can be realized for highly efficient desalination and dye-containing wastewater treatment with the aid of ambient energy. The present work demonstrates the efficient solar evaporation performance of ultra-low-cost evaporation membranes with the prospect of large-scale water purification treatment.

The optimization of evaporation rate in graphene-water system by machine learning algorithm

Solar interfacial evaporation, as a novel practical freshwater production method, requires continuous research on how to improve the evaporation rates to increase water production. In this study, sets of data were obtained from molecule dynamics simulation and literature, in which the parameters included height, diameter, height–radius ratio, evaporation efficiency, and evaporation rate. Initially, the correlation between the four input parameters and the output of the evaporation rate was examined through traditional pairwise plots and Pearson correlation analysis, revealing weak correlations. Subsequently, the accuracy and generalization performance of the evaporation rate prediction models established by neural network and random forest were compared, with the latter demonstrating superior performance and reliability confirmed via random data extraction. Furthermore, the impact of different percentages (10%, 20%, and 30%) of the data on the model performance was explored, and the result indicated that the model performance is better when the test set is 20% and all the constructed model converge. Moreover, the mean absolute error and mean squared error of the evaporation rate prediction model for the three ratios were calculated to evaluate their performance. However, the relationship between the height- radius ratio and optimal evaporation rate was investigated using the enumeration method, and it was determined that the evaporation efficiency was optimal when the height–radius ratio was 6. Finally, the importance of height, diameter, height– radius ratio, and evaporation efficiency were calculated to optimize evaporator structure, increase evaporation rate, and facilitate the application of interfacial evaporation in solar desalination.

Biomimetic polyaryl ether-based aerogels for efficient interfacial solar water vapor generation

There is an urgent need to design efficient photothermal layer, continuous water migration pathways, and stable insulation layer to simultaneously achieve ideal water and heat management in solar-powered interfacial evaporation systems. Here, we assemble into a biomimetic aerogel with down-feather-like shape by first introducing rigid polyaryl ether material of sulphonated poly (phthalazinone ether sulfone ketone) (SPPESK) for highly efficient and multifunctional solar interfacial evaporation drawing inspiration from the cavity structure and insulation strategy of the eagle wings. The biomimetic aerogel has an evaporation rate of 2.34 kg m−2h−1 at one solar irradiance, an energy efficiency of 91.7 %, and an output voltage of 316.7 mV when coated. The insights provided by this work into biomimetic structure displayed by chitosan/SPPESK/Mxene aerogels promise to translate photothermal conversion performance benefits measured in laboratories into real-world applications for continuous desalination and wastewater purification. We anticipate that our work is a starting point to utilize the full potential of photothermal properties of polyaryl ether-based materials.

Quantitative tailoring of water state of sulfonated corncob for boosting solar interfacial evaporation and salt resistance

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 (H2SO4) 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.

Photothermal Properties and Solar Water Evaporation Performance of Lignin-Based Polyurethane Foam Composites.

Solar interfacial evaporation is the most promising route for desalination because it is highly efficient, affordable and offers green energy. Polyurethane foam (PUF) is an ideal substrate material for efficient solar water evaporation because of its low thermal conductivity, affordability, and high efficiency for continuous water transport. However, PUF exhibits poor mechanical properties after water absorption and expansion, and lacks the photothermal conversion effect. In this study, biorefinery lignin with efficient photothermal properties was introduced to prepare functional lignin-based PUF (LPUF), and the relationship between the molecular structure of fractioned lignin and the solar water evaporation performance was systematically investigated. The addition of lignin effectively enhanced the mechanical properties of LPUF after water absorption and swelling, and imparted the foam with a photothermal conversion effect. The water evaporation rate of LPUF was as high as 2.58 kg m-2 h-1 and could be further improved to more than 3.0 kg m-2 h-1 after loading polyaniline (PANI) on the surface of LPUF. LPUF-PANI exerted an excellent purification effect on dye wastewater with outstanding long-term stability, providing a potential solution for ecofriendly and sustainable economic production of fresh water. This study broadens the effective utilization of LPUF bulk materials in the fields of energy and environment.

Numerical Simulation Technologies in Solar-Driven Interfacial Evaporation Processes.

Solar interfacial evaporation technology has the advantages of environmentally conscious and sustainable benefits. Recent research on light absorption, water transportation, and thermal management has improved the evaporation performance of solar interfacial evaporators. However, many studies on photothermal materials and structures only aim to improve performance, neglecting explanations for heat and mass transfer coupling or providing evidence for performance enhancement. Numerical simulation can simulate the diffusion paths and heat and water transfer processes to understand the thermal and mass transfer mechanism, thereby better achieving the design of efficient solar interfacial evaporators. Therefore, this review summarizes the latest exciting findings and tremendous advances in numerical simulation for solar interfacial evaporation. First, it presents a macroscopic summary of the application of simulation in temperature distribution, salt concentration distribution, and vapor flux distribution during evaporation. Second, the utilization of simulation in the microscopic is summed up, specifically focusing on the movement of water molecules and the mechanisms of light responses during evaporation. Finally, all simulation methods have the goal of validating the physical processes in solar interfacial evaporation. It is hoped that the use of numerical simulation can provide theoretical guidance and technical support for the application of solar-driven interfacial evaporation technology.

Experimental analysis of a solar interfacial evaporation under high power concentrator

Solar-driven interfacial evaporation in solar distillers is recently intensively investigated. This work presents a new distiller system based on bottom-heating/interfacial evaporation process driven by high power concentrated solar energy. This system applies Annual Fresnel solar concentration and a circular Fresnel lens, increasing input solar energy. The 1 D water supply wick is elected as the interfacial evaporator to satisfy water evaporation demand by capillary suction. Solar distillers with high-power concentrator are experimentally tested and the results are discussed in this work. This work aims at analyzing the bottom-heating/interfacial evaporation performance under concentrated sunlight. The concentration ratio of an Annual Fresnel solar concentration and a circular Fresnel lens is 62.4. Further optimization of the distiller is carried out according to the concentrators and low ambient temperature requirements of interfacial evaporation. Performances of different distillers are compared. The results show that, the cumulative freshwater productivity of the interfacial evaporation and bottom-heating distiller are 21.25 kg/(m2·day) and 15.98 kg/(m2·day), respectively. The maximum gain output ratio of the interfacial evaporation is 72.1%, higher than the bottom-heating distiller. The maximum temperature of interfacial evaporation surface is 81.53 C∘.

Equilibrium and optimization of water-heat transfer in natural cellulose-based hybrid hydrogel for efficient solar desalination

Solar interfacial evaporation for seawater desalination and wastewater purification is considered a promising strategy to alleviate the water scarcity crisis. Currently, the ways to improve evaporators usually revolve around iteration of photothermal materials (enhancing heat generation) or macrostructural remodeling (altering water transport rate), but these means have limitations and do not achieve simultaneous and precise regulation of water-heat utilization. Herein, a simple hydrothermal method is used to synthesize natural cellulose-based hybridized hydrogels, exhibiting a high evaporation efficiency (97.67%) and a full range of water purification capabilities, including antimicrobial, anti-salt accumulation, and degradation of organic dyes. Significantly, the enhancement mechanism of the energy-mass utilization of this evaporator can be explained from two aspects. Firstly, the hybridization of natural cellulose and inorganic carbon materials can supplement a large number of hydrophilic functional groups, thus fully activating the water molecules and reducing the evaporation energy consumption. Furthermore, the COMSOL simulation is used to clarify the distribution of water and heat, and by adjusting the height of the hydrogel, the balance of water-heat transfer is cleverly achieved with the maximization of energy utilization. Overall, the optimization idea of water-heat transfer provides a new direction for future evaporator design and a fresh opportunity for the improvement of energy-mass management model.

Interfacial Solar Evaporation: From Fundamental Research to Applications.

In the last decade, interfacial solar steam generation (ISSG), powered by natural sunlight garnered significant attention due to its great potential for low-cost and environmentally friendly clean water production in alignment with the global decarbonization efforts. This review aims to share the knowledge and engage with a broader readership about the current progress of ISSG technology and the facing challenges to promote further advancements toward practical applications. The first part of this review assesses the current strategies for enhancing the energy efficiency of ISSG systems, including optimizing light absorption, reducing energy losses, harvesting additional energy, and lowering evaporation enthalpy. Subsequently, the current challenges faced by ISSG technologies, notably salt accumulation and bio-fouling issues in practical applications, are elucidated and contemporary methods are discussed to overcome these challenges. In the end, potential applications of ISSG, ranging from initial seawater desalination and industrial wastewater purification to power generation, sterilization, soil remediation, and innovative concept of solar sea farm, are introduced, highlighting the promising potential of ISSG technology in contributing to sustainable and environmentally conscious practices. Based on the review and in-depth understanding of these aspects, the future research focuses are proposed to address potential issues in both fundamental research and practical applications.

Modular solar interfacial evaporation and crystallization– Functional partitioning

Solar-driven interfacial evaporation stands out as a low-energy, environmentally-friendly desalination approach with substantial potential for clean water recovery and resource harvesting. However, the stability of the system is compromised by an undesirable increase in salt accumulation. Herein, we designed a modular structure to separate functional areas. The whole structure contains an evaporator and a collector: the evaporator mainly takes on the function of evaporation and the collector is mainly used for the crystals collection. Operating under one sun illumination, the system attained a high evaporation rate of 2.34 kg m-2h−1 and a high solar-water evaporation efficiency of 133.19 %. Owing to the replaceable collector, the evaporation system maintained a consistently high evaporation rate even after 240 h of continuous operation, and up to 97 % of the solute was enriched in the collector. Furthermore, we investigated the impact of natural organic matter (NOM) on both evaporation and crystallization within the system. This study provides a new perspective on the design of solar interfacial evaporation and crystallization systems.

Solar interfacial evaporation for efficient treatment of sewage containing volatile organic compounds and toxic heavy metal ions: A sequential process of adsorption, coagulation, and evaporation

Solar interfacial evaporation (SIE) is an eco-friendly and sustainable technology for addressing water pollution and freshwater scarcity. However, treating wastewater containing volatile organic compounds and heavy metal ions with a single SIE method is inefficient. The combination of adsorption, coagulation, and evaporation process provides an alternative solution for treating this type of wastewater. In this study, activated carbon powder (C) is introduced as an adsorbent and an integral part of photothermal conversion material, which is coagulated with polyvinyl alcohol (PVA) and polyethylene glycol (PEG) through a mold press process to fabricate PVA/C/PEG composite hydrogels. The volatile organic compounds and heavy metal ions in the wastewater are adsorbed by the activated carbon powder and the wastewater is then further purified into freshwater through SIE. This stepwise “adsorption first, then coagulation and evaporation” method can not only rapidly remove pollutants from the raw water, but also provides a much higher removal efficiency than the adsorption-evaporation synergetic process. This work demonstrates a successful attempt to utilize the SIE method for treating wastewater containing volatile organic compounds and heavy metal ions.

Efficient Solar-Driven Interfacial Water Evaporator using Hydrogel Modified Carbon-Based Biomass with Abundant Microchannels.

The conventional sea water desalination technologies are not yet adopted worldwide, especially in the third world countries due to their high capital cost as well as large energy requirement. To solve this issue in a sustainable way an interfacial solar water evaporation device is designed and proposed in this article using the branches of Prunus serrulata (PB). The PB has abundant microchannels and shows excellent photothermal conversion capability after carbonization. Moreover, the easy access to raw materials and the facile fabrication process makes the solar water evaporating device very cost effective for seawater desalination application. Experiments show that in the presence of the fabricated evaporator the evaporation rate of water can reach 3.5kgm-2 h-1 under 1 sun, which is superior to many similar experimental devices. In addition, its advantages, such as effective sewage purification capability, low cost, and environmental friendliness, make this evaporator highly competitive in the extensive promotion of this technology and can be considered as a new sustainable solution for seawater desalination with great application potential and prospects.

A contactless 3D Janus evaporator with superhydrophobic core and superhydrophilic shell for efficient desalination and water purification

Solar interfacial evaporation is a low-cost strategy for desalination and water purification. However, for most evaporators, the coplanar configuration of light absorption and water evaporation results in a confined evaporation surface and salt deposition problems. Here, a contactless 3D Janus evaporator (Ag-NSP@BFP) with a core/shell structure is designed by wrapping Ag nanoparticles (Ag-NPs) decorated nickel sponge (Ag-NSP) using bamboo fiber paper (BFP). The superhydrophobic Ag-NSP core (absorber) achieves highly efficient light absorption and photothermal conversion. Meanwhile, the superhydrophilic BFP shell not only provides a larger evaporation area (side surfaces as evaporation surfaces) but also forms a 2D water channel to ensure sufficient water supply. Furthermore, polystyrene foam (EPS) isolates photothermal material from bulk water, minimizing heat transmission losses dramatically. The 3D Janus evaporator increases the evaporation area and harvests energy from the ambient environment, achieving an evaporation rate of up to 2.77 kg m−2h−1 and an energy conversion efficiency of 105.2%. Moreover, the Janus structure effectively inhibits salt accumulation on the photothermal surface and exhibits a good purification effect on wastewater containing dyes and heavy metal ions. Thus, combining a 3D evaporator with Janus structure to achieve efficient salt-resistant evaporation provides a new design idea for stable seawater desalination and wastewater purification.

Accelerating the desalination of seawater and elimination of cosmetic contaminants from tap water by depositing zinc copper vanadate microparticles on solar evaporators

Black garbage bags (BGB) and car air filters (CAF)) were recycled and used to elaborate interfacial solar evaporators, also named as recycled materials evaporator (RME). The RME evaporator desalinated seawater at a maximum evaporation rate and evaporation efficiency of 3.19 kg∙m-2∙h-1 and 80.1%, respectively, under natural sunlight. Later, the RME evaporator was completely coated with copper zinc vanadate (CZVO) microplates (RME-F-CZVO evaporator). Other two RME evaporators were made, one of them had printed a circle of CZVO particles at its center (RME-C-CZVO evaporator), while the second one had nine small circles of CZVO microparticles distributed on its surface (RME-D-CZVO evaporator). The highest evaporation rate (3.61 kg∙m-2∙h-1) and evaporation efficiency (90.4%) were reached for the RME-C-CZVO evaporator. Printing the CZVO microparticles with circular geometry at the center of the evaporator maximized the accumulation of heat, which in turn, accelerated the evaporation of the seawater. This effect was confirmed by thermographic images. In addition, the evaporators reduced the water vaporization enthalpy by 27-36.3%, which favored the steam generation at lower temperatures. Also, the evaporators were utilized for the purification of stream water (contaminated with organic compounds) and tap water contaminated with cosmetics (skin foundation and blush). The results indicated that 97–99% of the cosmetics was removed from the water after the evaporation treatment, and 95–99% of the total dissolved solids were eliminated as well. This investigation reveals that low-cost solar evaporators made of recycled plastics/cellulose can desalinate seawater or could serve to eliminate cosmetics with complex composition from the tap water.