Water Evaporation Research Articles

Preparation of Calcium Alginate-Based Hydrogels with Precisely Designed Centrosymmetric Geometries for Efficient Water Evaporation in Response to Different Solar Incidence Angles.

Hydrogels are popular materials for desalination and can significantly reduce the vaporization enthalpy of water; however, there are few reports on hydrogels with a controllable multilevel structural design for water evaporation. Herein, a calcium alginate and traditional Chinese ink-based evaporator (CIE) are proposed and fabricated using directed freezing technology to construct radial channels, followed by freeze-drying and physical cross-linking. Because of the squeezing of ice crystals and the shaping effect of the PDMS template, the prepared evaporator exhibits a sea-urchin-shaped highly geometrical centrosymmetric structure with numerous multilevel pore channels, which promotes the rapid transport of water under different solar incidence angles as the sun rotates as well as overcomes the structural shrinkage of the hydrogel caused by insufficient water supply. Additionally, the radial channels in the spherical hydrogel overcome the traditional limitation of saltwater being continuously concentrated in the same area where the evaporation rate is the highest. As a result, the urchin-structured CIE exhibits a water evaporation rate of 3.52 kg m-2 h-1 at 1 sun irradiation, which is 45.5% higher than that of the unpatterned CIE. This multilevel structural design provides a strategy for the fabrication of an all-day water hydrogel-based evaporator without structural shrinkage under solar irradiation.

Utilization of Thermal-Activated Coal Gangue to Enhance the Properties of Sandy Soil Composites

To effectively solve the problem of land sanding and improve the water- and element-retaining properties of sandy soil, a thermal-activated coal gangue (TACG) was used as an ameliorating material to prepare a composite soil mixed with sandy soil to enhance the water-retaining and fertilizer-fixing properties of the sandy soil and reduce the evaporation of water in the soil. The structure and thermal stability of the gangue were characterized using Fourier transform infrared spectroscopy and thermogravimetric analysis. By applying different dosages and different calcination temperatures of the TACG, the water-holding capacity of the mixed soil was determined, and changes in pore structure were observed. When the dosage was 15% and the calcination temperature was 600 °C, the mixed soil possessed the most excellent distribution of pore structure and could effectively prevent water evaporation. Meanwhile, the application of the TACG in sandy soil improved its adsorption of K+, which showed the potential application of thermally activated gangue materials in the field of soil improvement.

Kinetic Control of Self-Assembly Pathway in Dual Dynamic Covalent Polymeric Systems.

Kinetically controlled self-assembly is garnering increasing interest in the field of supramolecular polymers and materials, yet examples involving dynamic covalent exchange remain relatively unexplored. Here we report an unexpected dynamic covalent polymeric system whose aqueous self-assembly pathway is strongly influenced by the kinetics of evaporation of water. The key design is to integrate dual dynamic covalent bonds-including disulfide bonds and boroxine/borate-into a dynamic equilibrium system of monomers, polymers, and materials. This dual dynamic covalent design allows polymer growth and crosslinking to occur with the same spatiotemporal characteristics, governed solely by solvent evaporation. We found that a single building block can assemble into two distinct types of polymeric materials, each characterized by unique crosslinking topologies, orders, solubility, and macroscopic properties. The dual dynamic nature of the materials imparts them with intrinsic reconfigurability, such as interfacial repairability and close-loop chemical recyclability.

Kinetic Control of Self‐Assembly Pathway in Dual Dynamic Covalent Polymeric Systems

Kinetically controlled self‐assembly is garnering increasing interest in the field of supramolecular polymers and materials, yet examples involving dynamic covalent exchange remain relatively unexplored. Here we report an unexpected dynamic covalent polymeric system whose aqueous self‐assembly pathway is strongly influenced by the kinetics of evaporation of water. The key design is to integrate dual dynamic covalent bonds—including disulfide bonds and boroxine/borate—into a dynamic equilibrium system of monomers, polymers, and materials. This dual dynamic covalent design allows polymer growth and crosslinking to occur with the same spatiotemporal characteristics, governed solely by solvent evaporation. We found that a single building block can assemble into two distinct types of polymeric materials, each characterized by unique crosslinking topologies, orders, solubility, and macroscopic properties. The dual dynamic nature of the materials imparts them with intrinsic reconfigurability, such as interfacial repairability and close‐loop chemical recyclability.

Impact of Comb Cell Diameter on Nectar Evaporation Efficiency in Honey Bees

Honey bees transform nectar into honey through a combination of physical and chemical processes, with the physical process primarily involving the evaporation of excess water to concentrate the nectar. However, the factors affecting evaporation efficiency, such as evaporation duration, cell type, and bee species, remain incompletely understood. This study aimed to examine how these factors affect nectar evaporation efficiency during honey production. We measured the sucrose content in solutions subjected to combined active and passive evaporation, as well as passive evaporation alone. The results showed that eastern honey bee (EHB; Apis cerana) colonies were more efficient at concentrating sucrose solutions in worker cells than in drone cells under both combined active and passive evaporation conditions, as well as passive evaporation alone. Conversely, western honey bee (WHB; Apis mellifera) colonies exhibited greater efficiency in drone cells. Additionally, EHB colonies were more effective than WHB colonies in converting sucrose into fructose and glucose. Under passive evaporation, EHB colonies required at least 48 h to significantly concentrate the sucrose solution, while WHB colonies achieved similar concentrations in just 24 h. Sucrose content increased with the duration of passive evaporation. These findings provide insights into how honey bee colonies can efficiently produce mature honey during periods of abundant nectar flow.

Advances in photothermal water evaporation: synthesis, mechanisms, and coupled techniques

Advances in photothermal water evaporation: synthesis, mechanisms, and coupled techniques

Involving degradation products provides a new perspective of diffuse pollution assessment of atrazine with a modified mass balance approach.

Atrazine (ATR) is an endocrine disruptor known for its persistence and mobility. While the diffuse characteristics and potential risks of ATR have been extensively studied, its transregional migration and degradation characteristics have received less attention. In this study, a modified mass balance approach considering the diffuse source (DS), tributaries, water resource usage, degradation, adsorption, and evaporation was developed based on the traditional mass balance framework and field sampling to estimate the DS fluxes of ATR in a large river basin. Field sampling revealed that the ATR concentration in the surface water increased downstream, whereas the ATR levels in suspended particulate matter decreased. The ATR degradation ratio also decreased downstream, suggesting increased input along the river. The modified mass balance approach identified DS as the primary ATR source in the river, followed by tributaries. Together, the DS input and tributary inflow accounted for 95.6 % ± 2.1 % of the total ATR flux, with DS alone contributing 73.8 % ± 10.2 %. Finally, the ATR parent and its hazardous materials (ATR, desethylatrazine, and desisopropylatrazine) accounted for 6 % and 27 %, respectively, of the total ATR content that reached the estuary. This integrated consideration of ATR and its degradation products offer a new perspective on their transregional migration and degradation patterns resulting from diffuse pollution.

Analysis of Groundwater Hydrochemical Variation and Its Source During the Low Water Level Period in the Southern Oasis Area of Gaochang District, Turpan City

To explore the changes in groundwater hydrochemistry and its source influence in the low water level period of the southern oasis area of Gaochang District, Turpan City before and after the management of groundwater overexploitation, based on 12 groups of water samples in 2016 （three groups of unconfined water, nine groups of confined water） and 18 groups of water samples in 2023 （five groups of unconfined water, thirteen groups of confined water）, mathematical statistics, hydrochemical diagraph, hydrogen and oxygen isotope means, and an absolute principle component-multiple linear regression （APCS-MLR） model were used to analyze the changes and sources of groundwater hydrochemistry. The results showed that due to the dynamic conditions of groundwater, the dominant cation changed from Na+ to Ca2+, and the anion changed from HCO3- to SO42-. The dominant cation of confined water changed from Ca2+ to Na+, and the dominant anion remained unchanged as SO42-. The main supply source of both unconfined water and confined water was atmospheric precipitation, which was affected by evaporation, and the effect of evaporation of unconfined water was greater than that of confined water. The chemical composition of groundwater was mainly controlled by rock weathering and cation exchange. Na+, Ca2+, and Mg2+ were mainly derived from the dissolution of evaporative salt rock and silicate salt rock. NO3- was mainly derived from agricultural fertilizers, human and animal manure, and domestic sewage. Leaching and enrichment （F1）, agricultural activity and primary geological activity （F2）, and industrial activity （F3） were the main factors affecting groundwater chemistry in the study area, and the contribution rates were 58.41%, 18.12%, and 9.12%, respectively.

Bioinspired Pyramidal Array Photothermal Structure for Highly Efficient Water Evaporation under Omnidirectional Illumination.

Solar-driven interfacial evaporation is regarded as a green and sustainable strategy to address the global freshwater crisis. Nevertheless, it remains challenging to develop a photothermal structure with highly efficient evaporation under omnidirectional illumination. Herein, a three-dimensional multiscale pyramidal array photothermal structure (PAPS) was developed from the inspiration of durian skin. It consisted of macroscale three-dimensional pyramidal array structures to enhance light absorption and increase the evaporation area, microscale porous structures to ensure continuous water transport and facilitate vapor diffusion, and nanoscale protrusion structures with hybrid photothermal materials of CuxO/C to enhance light trapping and photothermal conversion efficiency. It was fabricated in a porous foam matrix by a facile milling process. The PAPS induced an evaporation rate of 2.08 kg/m2h under one sun illumination under direct light conditions, which was 24% higher than that of a planar photothermal structure. The PAPS maintained fairly good evaporation performance under inclined light conditions, i.e., the evaporation rate of the PAPS was 1.72 kg/m2h at 45° inclined light angle. It only decreased by 17% compared to the direct sunlight conditions, which was much smaller than the 29% decrease of the planar photothermal structure. Additionally, the PAPS present a large evaporation rate of 6.29 kg/m2h under one sun illumination in air convection conditions with a wind speed of 3 m/s. This work provided a high-performance pyramidal array photothermal structure for highly efficient water evaporation under omnidirectional illumination, which provides potential opportunities for stable solar desalination and freshwater supply in complex and variable environments.

3D‐Printed Hemispherical Capillaries for Solar Water Evaporation

3D‐Printed Hemispherical Capillaries for Solar Water Evaporation

Z-scheme BiOBr/WS2 heterojunction with integrated photocatalytic degradation and photothermal water evaporation for effective dye wastewater purification

The restoration of water resources and the optimization of solar energy use are critical challenges. In this study, hydrophilic BiOBr/WS2 Z-scheme heterojunctions were prepared using a series of reactions for solar interface water evaporation and photocatalytic degradation of RhB. WS2 nanoparticles were deposited on the surface of titanium mesh using a hydrothermal method, and BiOBr nanosheets were further modified on WS2 using a successive ionic layer adsorption reaction (SILAR) method and solvothermal method. The relatively broad absorption range of WS2 in the full spectrum resulted in enhanced light absorption and improved light utilization of BiOBr/WS2. The formation of Z-scheme heterojunction between BiOBr and WS2 improved the hydrophilicity of the material, enhanced the photocatalytic degradation of organic pollutants in BiOBr/WS2 composite materials, and improved the solar interface water evaporation performance. The degradation rate of RhB by BiOBr/WS2 could reach 95.6% under one solar irradiation, and the photothermal water evaporation rate could reach 1.81 kgꞏm-2ꞏh-1. This study solved the problem of dye enrichment on solar absorber and provided a new way to construct an efficient solar interfacial water evaporation-photocatalytic system to treat dye wastewater.

Photothermal CuS@SiO2 nanocomposites for solar-driven anti-icing/deicing and synchronous evaporation and photocatalysis

Development of CuS@SiO2 nanocomposites into superhydrophobic photothermal (SHP) CuS@SiO2 coating for anti-icing/deicing, and Janus CuS@SiO2-MF evaporator for synchronous photocatalytic dye degradation and water evaporation.

Thin free-standing liquid films manipulation: device design to turn on/off gravity in flow regimes for thickness map control and for material structuring.

The manipulation and control of free-standing liquid film drainage dynamics is of paramount importance in many technological fields and related products, ranging from liquid lenses to liquid foams and 2D structures. In this context, we theoretically design and introduce a device where we can reversibly drive flow regime switch between viscous-capillary and viscous-gravity in a thin free-standing liquid film by altering its shape, allowing us to manipulate and stabilize the film thickness over time. The device, which mainly consists of a syringe pump, a pressure transducer, and a 3D-printed cylinder, is coupled with a digital holography setup to measure, in real time, the evolution of the local film thickness map, revealing characteristic features of viscous-capillary and viscous-gravity driven drainage regimes. By using polyvinyl alcohol/water concentrated solutions, we are also able to produce viscoelastic membranes after manipulation and water evaporation, which presents manipulation history-dependent geometrical properties. Furthermore, using a system composed of carboxymethyl cellulose, water, and rod-like zinc oxide nanoparticles, we show a clear effect of film manipulation on particle rearrangement. We believe this device could represent a starting point for the development of a useful and practical tool to study thin liquid film dynamics and to produce novel (patterned) 2D structures for the numerous scientific and technical fields where they are of use.

Effect of laminate channel width on the performance of MgAl-layered double hydroxide film-based nanogenerators driven by water evaporation

Effect of laminate channel width on the performance of MgAl-layered double hydroxide film-based nanogenerators driven by water evaporation

How does the polymer type affect the rate of water evaporation from polymer solutions?

Drying of aqueous polymer solutions is widely used to form polymer films. However, we do not fully understand how concentrated polymer near the drying interfaces decreases the rate of water evaporation. In addition, we do not know how the evaporation kinetics varies when we use different polymers. To understand these topics, we examined drying of polymer solutions with three different polymers, poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone), and poly(ethylene glycol) in unidirectional drying cells. In each case, the water evaporation rate (J) decreased to 1/10 of the initial rate during evaporation. J-1 was proportional to the amount of polymer transported to the drying interface during the drying time. The slope is defined as resistance factor A and the PVA solutions had larger A values than the other polymers, indicating that J decreased more noticeably in the PVA solutions. The molecular weights of the polymers did not explain A. Concentration profiles of polymers near the drying interfaces were quantified in situ with an optical microscope by exploiting differential interference contrast, from which we estimated the diffusion constants (Ds) of the polymers in the drying solutions. We found that A was negatively correlated with D. This result clearly indicates that the diffusivity and accumulation of dissolved polymer molecules near the drying interface governs the overall drying kinetics of their solutions.

Prilling of crystallizable water-in-oil emulsions: Towards co-encapsulation of hydrophilic and lipophilic active ingredients within lipid microparticles.

Multiparticulate drug delivery systems offer advantages in controlled release, dose flexibility, and personalized medicine. Fusion prilling, a process that produces spherical lipid-based microparticles through vibrating nozzles, is gaining interest in the field. This study aims to explore the use of fusion prilling to encapsulate crystallizable water-in-oil emulsions, enabling the incorporation of hydrophilic active pharmaceutical ingredients (APIs) within lipid matrices. Urea (highly water-soluble) and Erythromycin (poorly water-soluble) were selected as model compounds, solubilized in the aqueous and lipid phases, respectively. The first phase of the study evaluated lipid excipients for their suitability in prilling, ensuring microparticle consistency in shape, size, and stability. The second phase focused on characterizing microparticles notably in terms of structural organization and integrity. Results demonstrated successful encapsulation of both model compounds, with high efficiency, by omitting an additional emulsification step. Despite concerns over water evaporation during processing, microparticles remained stable for up to 14 months when stored at room temperature in a hermetically sealed container. This work highlights the potential of fusion prilling for multiparticulate drug delivery systems, even for formulating APIs with different solubility profiles. Future research should focus on optimizing the process for broader API incorporation.

Ultralight aerogels with aligned channels for efficient solar driven interfacial evaporation of brackish water and remediation of saline soils

Solar driven interfacial evaporation (SDIE) holds significant potential in water treatment and soil improvement. This study innovatively designed a photothermal water purification and soil amelioration system based on salt crystallization migration. Its purpose is to efficiently purify brackish water and improve saline-alkali soil using solar stream evaporator. The core of this system lies in the utilization of cellulose nanofibers (CNF), vinyltrimethoxysilane (VTMO), and carbon nanotubes (CNT) as raw materials. The hydroxyl groups provided by CNF chemically crosslink with the methoxy groups provided by VTMO, and a gradient temperature reduction method is employed to shape a photothermal material (CNT-V-CNF) with aligned channels. CNT-V-CNF exhibits high light absorption (95 %), superhydrophilicity, and excellent thermal insulation properties, enabling a high photothermal evaporation rate (1.7 kg·m−2·h−1). The incorporation of the salt migration carrier significantly strengthens the salt tolerance of CNT-V-CNF, allowing it to maintain efficient and stable photothermal conversion performance in actual brackish water conditions. This achievement results in a daily water production capacity of 10.23 kg·m−2·d−1. After irrigating saline-alkaline soil with the purified freshwater for 52 days, the germination rate of wheat seeds sown in the soil has increased by approximately 65 %. The results of this study demonstrate the tremendous potential of SDIE centered on CNT-V-CNF in the agricultural irrigation and soil remediation practices.

Gradient engineering in interfacial evaporation for water, energy, and minerals harvesting

Gradient engineering in interfacial evaporation for water, energy, and minerals harvesting

Comparative Effects of Superhydrophobic Sand and Plastic Mulches on Growth and Yield of Sweet Pepper (Capsicum annum L.) under Arid Environments

Superhydrophobic sand (SHS) is a plastic-free mulching technology that reduces surface evaporation of water from irrigated soils. Here, we present the results of two experimental field trials conducted in the 2019–20 and 2021–22 cropping seasons, comparing the efficacy of SHS with those of traditional plastic mulches on the growth and yield performance of sweet pepper (Capsicum annum L.) plants. The experiments were conducted at the King Abdulaziz University (KAU) agriculture research station at Hada Al-Sham (21˚48′3″N, 39˚43′25″E), Al-Jamoom, Saudi Arabia. The effects of bare soil (i.e., control treatment), 5 mm SHS thickness, and 10 mm SHS thickness, along with white and black plastic mulches (120-μm-thick polyethylene) were recorded on the plants via a randomized complete block design with three replicate plots. We found significant benefits of all of the mulches during the 2021–22 season, as evidenced by 51% (P < 0.001), 31% (P = 0.0102), and 32% (P = 0.0048) more fruits for the 10-mm SHS, white plastic, and black plastic mulches, respectively, compared with the unmulched controls. Consequently, the total fruit yield per plant increased by 112% (P = 0.000), 71% (P < 0.001), and 83% (P < 0.001), under 10 mm SHS, white plastic, and black plastic mulches, respectively. Curiously, the field trial conducted in 2019 in an adjacent field did not reveal significant benefits of SHS, which we attribute partially to erratic rain showers and field heterogeneity. Taken together, this study and our previous work show that 10-mm-thick SHS mulch is optimal for boosting irrigation efficiency in regions where water is a limiting factor. Unlike plastic mulches, SHS biodegrades in <1 year and becomes a part of the sandy soil matrix, thereby obviating landfilling. Thus, the benefits of SHS exceed those of plastic mulches in terms of closing the yield gap and carbon footprint. These findings underscore the potential of SHS as a sustainable solution for growing plants in hot and dry arid regions in Saudi Arabia and globally.

Microbiological and Physicochemical Characterization During Biodrying of Organic Solid Waste

The correct management of high-moisture organic waste (HMOW) is crucial to minimize its environmental impact and take advantage of its potential as a valuable resource, thus linking it to the circular economy, sustainable production and recycling. Processes such as anaerobic digestion, composting and, more recently, biodrying have been applied to support the sustainable management of HMOW. However, the latter has not yet been well characterized, so this study focuses on elucidating the behavior of microbial populations and their relationship with physical and chemical conditions during biodrying. In a greenhouse, a semi-static pile with an initial water content of 88%, composed of orange peel waste (80%), sugarcane bagasse (16.5%) and mulch (3.5%) was biodried for 50 days. Biodrying went through three stages: (1) the mesophilic stage, when different microbial populations decompose some organic matter, causing a temperature increase from 25 to 40 °C; (2) the thermophilic stage, in which the highest microbial counts were found, most of which corresponded to the highest temperatures reached and maintained between 40 and 62 °C, and, consequently, to the greatest decrease in water content (from 78 to 41%); and (3) the cooling phase, when the temperature dropped to 23–25 °C. The aeration and mainly the microbial activity were responsible for most of the water evaporation. Microbial activity in biodrying of HMOW ended on day 32, when the humidity was lower than 30% and the water activity (aw) was below 0.8. After that, moisture loss was carried out only by convection and radiation. Obtained biodried organic waste (10% water-content) could be used as an alternative fuel in many industries.