Surface Evaporation Research Articles

New insight into the role of Cu addition on surface nanocrystallization and corrosion behavior of aluminum alloy

Realization of surface-reinforced aluminum alloys with excellent corrosion resistance remains a major topic. Herein, a novel method based on combination of electron beam evaporation plating and surface alloying was proposed. Results revealed that the current density is one order of magnitude less than that of the substrate and that the impedance value is doubled. The nanometer-scale refinement of the grains and the homogenous dispersion of nanocrystallization Al2Cu in the modified layer of aluminum alloy contributed to the enhancement of corrosion resistance. This study is expected to provide a new sight for the development of Cu-reinforced high-performance aluminum alloys.

Total Resource Circulation of Desalination Brine: A Review

AbstractDesalination brine is a concentrated stream that is generated during the desalination process. Brine commonly has high salinity and TDS (total dissolved ions), which contains ions such as Na+, K+, Ca2+, Mg2+, Cl−, SO42−, HCO3−, PO43−, and some critical elements. Currently, the brine treatment mainly applies direct disposal, like surface water discharge, sewer discharge, deep‐well injection, and evaporation ponds. However, these methods can cause harm to marine ecosystems, soil, and groundwater. Therefore, brine can be regarded as a resource to be reutilized. This work then aims to highlight the novel developments of brine application. For example, Na, Ca, and Mg in brine can be employed for carbon capture and utilization with ammonia, amines, and alkaline substances. With slight adjustment, brine can also be directly used as irrigation water, aquaculture water, and the activation of biochar. Furthermore, brine holds a higher concentration of critical elements, which makes many countries and scholars start to conduct element extraction, reducing the amount of ore exploitation. At last, the major obstacles related to these advancements in sustainability, expenses, and technological aspects are outlined, and promising research trends of brine reutilization are also suggested.

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.

Tree transpiration-inspired cellulose aerogel with engineered cold-evaporated surface for promoting structural stability and minimizing energy loss

Solar-driven evaporation technology could significantly relieve the fresh-water crisis in the world. However, several problems, such as poor structural stability, low photothermal conversion capacity, and single heat source of traditional evaporators limited the promotion of fresh-water production efficiency. Herein, inspired by tree transpiration, we report a hydrophilic three-dimensional (3D) cellulose-based evaporator similar to the root of a tree, which can pump the bottom water to the evaporation surface for vapor generation. The aldehyde-based cellulose nanocrystals/ethylene imine polymer (ACP) aerogel was developed through Schiff base reaction to enhance the chain entangle capacity of the cellulose nanocrystals (CNCs) aerogel in water. Coating the ACP aerogel with lignin-derived photothermal material created the double-layered solar-driven evaporator (ACP-7LM), achieving a remarkable surface temperature of 35.9 °C in water under 1 sun irradiation for 1 h. The ACP-7LM exhibited an impressive evaporation rate of 1.60 kg m−2 h−1, leveraging its structural stability and excellent photothermal conversion. Increasing the cold evaporation surface (adjusting exposure height from 0 cm to 4 cm) of ACP-7LM aerogel maintained a lower temperature compared to ambient temperature on the side surface during evaporation, which harvest heat energy from environment and minimize energy loss. This enhanced environmental heat absorption boosted the ACP-7LM's evaporation rate to 3.76 kg m−2 h−1, a 2.35-fold increase over the ACP-7LM (0 cm). This solar-driven evaporator offers an efficient, innovative approach to elevate evaporation rates and address the global water crisis by simultaneously enhancing heat absorption capacity and photothermal conversion efficiency.

Evaporation of nonspherical droplets on chemically patterned substrate considering gravity: A computational study

A liquid–solid interaction-based dynamic mesh model simulated evaporation of nonspherical droplets on a patterned substrate. The model includes contact angle hysteresis, ensuring droplets’ initial morphology follows minimum energy principles. The evaporation model was validated against experiments with both spherical and nonspherical droplets. Investigation of 70μL droplets under three gravity conditions revealed distinct morphological behavior: the sessile droplet exhibited increasing interfacial curvature radially, the pendant droplet showed decreasing curvature, and the microgravity droplet maintained nearly constant curvature. Droplet morphology affected flow and temperature distributions during the CCR mode at different substrate temperatures. The pendant droplet exhibited higher interfacial temperature difference and average velocity at Tw=298.15K, while the sessile droplet had the highest values at Tw=328.15K. Evaporative flux distribution differed, with the pendant droplet having higher flux near the top, and the sessile droplet near the contact line. Entering the CCA mode reduced morphology’s influence on evaporation, converging evaporative flux and rate among droplets. This study confirms that gravity enhanced droplet evaporation, and a proportional relationship exists between evaporation rate and the square root of the evaporative surface area for droplets in the same evaporation mode.

Simulation of Diurnal Evolution of Evaporation Zone during Soil Drying after Rainfall

To better understand processes involved in the evaporative drying of the soil, simulations on the dynamics of the evaporation zone, condensation zone, and dry surface layer (DSL) were conducted during a 10-day drying event under diurnal atmospheric conditions. Simulated water contents and soil temperatures matched well with the measured data in the lysimeter. Surface evaporation predominantly occurred during the early period each day, while subsurface evaporation dominated during the remaining part of the day. The evaporation zone presented a distinctly diurnal pattern, moving toward the deeper soil layer during the daytime and back toward the soil surface during the nighttime. The DSL and condensation zone, located immediately above and below the evaporation zone, respectively, also presented diurnal patterns following those of the evaporation zone. As soil drying progressed, both the position of the evaporation zone within the profile and the DSL width exhibited an overall increasing trend, reaching about 4.9 mm by the end of the study period. The occurrence of condensation zones was limited to the daytime when there was a downward surface temperature gradient present. Diurnal patterns observed in both evaporation zones and DSL could potentially be determined by quantifying changes in the near-surface profile’s soil water content, relative humidity, pressure head, and vapor density.

Spatial Patterned Interfacial Solar Evaporators toward Recovering Heat Loss.

The novel freshwater production technology, such as interface solar-steam conversion (ISSC) technology, has advanced so rapidly recently, where its energy capture and conversion process was localized at the air-water interface so as to achieve high efficiency of energy utilization and transformation. However, when enlarging the evaporation surface and application scale, the inevitably increased heat loss and reduced conversion efficiency put it in a dilemma: should we exploit innovative steamer constructs for practical applications. In order to effectively mitigate heat loss from the evaporator to the surrounding environment, a series of spatial pattern evaporators (SPEs) are specifically designed in this article. By recovering the energy of radiation and convection heat loss, SPEs achieved low heat loss in an open evaporator through unequal height auxiliary heat exchange platforms. In an open environment, it achieves a maximum evaporation rate of 1.68 kg m-2 h-1, with approximately 52.41% of the heat loss being reabsorbed. This sophisticated pattern design provides a promising guideline for optimizing thermal management strategies and promoting practically scalable applications.

Decomposing the role of dry intrusions for ocean evaporation during mistral

AbstractThe mistral is a northerly gap‐wind regime blowing through the Rhone Valley in Southern France. It is held responsible for the sea‐surface cooling necessary to produce deep convection in the Gulf of Lion through turbulent ocean heat loss. The mistral is tightly connected to lee‐cyclogenesis in the Gulf of Genoa, where topography forces substantial downward motion. Dry intrusions (DIs) are airstreams forming the descending branch of extratropical cyclones. Known to induce cold and dry surface anomalies, DIs are potential contributors to enhanced surface evaporation during mistral. In this study, a climatological database (ERA‐INTERIM, 1981–2016) of mistral–DI co‐occurrence is constructed, allowing quantification of the impact of DIs on the mistral evaporative hot spot for the first time. We find that, on average, mistral–DI evaporation rates are doubled, compared to mistral without DIs. Moreover, cluster‐composite analysis reveals amplifications exceeding 300% between dynamically similar mistral events, with response to DIs. Daily latent heat‐flux anomalies in the Gulf of Lion are decomposed into contributions from the various parameters to analyse the mistral evaporation response to DIs. Mistral–DI events are shown to produce extreme evaporation rates through increased mistral wind speeds. The results highlight the downward momentum flux delivered by DIs to the mistral at the Gulf of Lion as the primary driver of the evaporation amplification mechanism. We further explore the variability between different mistral–DI events and conclude that extreme mistral–DI evaporation events are linked to descending air trajectories entering the Gulf of Lion at an early stage of their lifetimes. These DIs charge the mistral with maximum vertical momentum fluxes, which act to intensify surface winds and hence evaporation rates.

Impact Analysis of H2O Fluxes and High-Frequency Meteorology–Water Quality: Multivariate Constrained Evaporation Modelling in Lake Wuliangsuhai, China

It is imperative to elucidate the process of evaporation in lakes, particularly those that are freshwater and are situated in middle and high latitudes. Based on one-year evaporation and high-frequency meteorological–water quality data of Lake Wuliangsuhai, this study analyzed the applicability and driving mechanism of the evaporation model. These dynamics are elucidated by the vorticity covariance method combined with the multivariate constrained evaporation Modelling method. The findings of this study revealed that (1) Lake evaporation (ET) is affected by multiple meteorological–water quality constraints, and the water quality indicators significantly related to ET are also affected by lake stratification. The coupled meteorological–water quality evaporation model can explain 93% of the evaporation change, which is 20% higher than the traditional meteorological Modelling evaporation model. (2) The nighttime ET is mainly affected by the thermal inertia lag, and the nighttime ET loss in Lake Wuliangsuhai accounts for 37.34% of the total evaporation, which cannot be ignored. (3) The actual water surface evaporation of the lake is much smaller than that measured by the pan conversion method and the regional empirical C formula method. The cumulative evaporation of Lake Wuliangsuhai from the non-freezing period to the early glacial period converted from meteorological station data is 1333.5 mm. The total evaporation in the non-freezing period is 2.77~3.68 × 108 m3, calculated by the lake area of 325 km2, while the evaporation calculated by the eddy station is 1.91 × 108 m3. In addition, the ET value measured by the cumulative C formula method was 424.2% higher than that of the model method and exceeded the storage capacity. Low-frequency and limited environmental index observations may lead to an overestimation of the real lake evaporation. Therefore, in situ, high-frequency meteorological–water quality monitoring and the eddy method deserve more consideration in future research on lake evaporation.

Novel data-driven optimal control methods for cost-effective brine treatment

This study presents a novel data-driven optimal control method to minimize the cost of Convection-Enhanced Evaporation (CEE) systems under time-varying weather conditions. CEE is the approach of evaporating water from saline films (brine) on packed evaporation surfaces by air convection. Here, operating variables (brine injection rate, brine temperature, and air speed) are actively controlled as a function of current ambient conditions and daily weather forecast. The controller optimizes the process operation variables based on a dataset consisting of Pareto fronts, obtained in advance by solving a set of optimization problems. Three optimal operation strategies are presented: (1) real-time selection of operating variables, (2) predictive scheduled operation, and (3) hybrid wind-fan operation. The effectiveness of the proposed strategies was assessed through two case studies with distinct geographical locations and weather conditions: Alamogordo, New Mexico, and Minneapolis, Minnesota. The results show significant cost-saving potential relative to static operation. Predictive scheduled operation resulted in an annual average operating costs of $0.91/m3 and $6.63/m3 in Alamogordo and Minneapolis, respectively, with the higher costs in Minneapolis a result of the added thermal energy required to prevent freezing in winter.

Salt-resistant solar water desalination system via surface modification and configuration engineering

Floating solar water desalination systems have received a lot of attention since they are portable, low cost, environmentally friendly, and highly efficient. However, salt accumulation on the evaporation surface and water transfer channels is one of the main obstacle to the development of these systems. In this work, two strategies of surface modification and configuration engineering are focused on to make the devices salt-resistant. First, the system becomes salt-resistant by formation of a hydration layer on the water manager and light absorber surface through cross-linking of polyethylene glycol diacrylate. Remarkably, the surface-modified device shows a water evaporation rate of 1.34 kg.m−2.h−1 and a conversion efficiency of 91.75 % in artificial seawater. There is no salt accumulation on the evaporation surface of surface-modified devices after desalination in the simulated seawater. In the second strategy, the water transferring to the evaporation surface and water evaporation rate are balanced by tuning the number of water transport channels and location. The engineered device shows an evaporation rate of 0.98 kg.m−2.h−1 and an efficiency of 75.5 % in a high saline solution (20 wt% NaCl). Simultaneous surface modification and configuration engineering improve the salt resistivity, showing that the configuration should be engineered according to the water salinity.

A Superior Catalytic Air Electrode with Temperature-Induced Exsolution toward Protonic Ceramic Cells.

Protonic ceramic cells merit extensive exploration, attributed to their innate capabilities for potent and environmentally benign energy conversion. In this work, a temperature-induced exsolution methodology to synthesize SrCo0.5Nb0.5O3-δ (SCN) nanoparticles (NPs) with notably elevated activity on the surface of PrSrCo1.8Nb0.2O6-δ (PSCN) is proposed, directly addressing the extant challenge of restrained catalytic activity prevalent in air electrode materials. In situ assessments reveal that SCN NPs commence exsolution from the matrix at temperatures surpassing 900 °C during straightforward calcination processes and maintain stability throughout annealing. Notably, the resultant SCN-PSCN interface facilitates vapor adsorption and protonation processes, which are poised to enhance surface reaction kinetics pertaining to the proton-involved oxygen reduction and evolution reaction (P-ORR and P-OER). A fuel-electrode-supported protonic ceramic cell leveraging SCN-PSCN as the air electrode manifests compelling performance, attaining a peak power density of 1.30 W·cm-2 in the fuel cell modality and a current density of 1.91 A·cm-2 at 1.3 V in the electrolysis mode, recorded at 650 °C. Furthermore, density functional theory calculations validate that the introduction of SCN NPs onto the PSCN surface conspicuously accelerates electrode reaction rates correlated with P-ORR and P-OER, by significantly mitigating energy barriers associated with surface oxygen and vapor dissociation.

Salt rejection/discharge strategies of a reverse-distillation device with a water layer for sustainable solar desalination: From two dimensions to three dimensions

The recently proposed solar-driven reverse-distillation device with a water layer has shown promising potential in solar energy conversion efficiency and impactful advantages in salt rejection by constructing a rapid brine flow driven by gravity/density differences. However, a lack of profound understanding and explanation of the salt-rejection mechanism and accurate salt-discharge regulation strategies may hinder the further improvement of reverse-distillation devices. In this paper, we thoroughly discuss and analyze the mechanism of how gravity affects the internal brine flow and determines the salt rejection/discharge performance while providing comprehensive salt-discharge regulation strategies for feed brine with a wide range of salinities. The results show that only a 4° inclination angle enables the two-dimensional (2D) device with a 1-mm-thick water layer in the dissolution mode to dispose 3.5 wt% brine for 8 h without salt saturation, while the value is also merely 10° for a three-dimensional (3D) device, indicating the realization of the brine flow driven by a small gravity component and demonstrating a strong adaptability for the device. In the salt discharge mode, the ratio of the discharge flow rate to the evaporation rate determines the salt saturation risk. We discuss the salinity distribution of the evaporation surface at varied feed-brine salinities and discharge flow rates, providing a theoretical basis for precisely matching the thermal characteristics and enabling improved design for efficient and sustainable solar-distillation devices. Finally, we discuss the scalability of salt rejection and propose a scheme for scalable water production, which may offer important support for further realizing large-scale sustainable solar desalination by using the reverse-distillation device with a water layer.

Contribution of anthropogenic aerosols to persistent La Niña-like conditions in the early 21st century

The discrepancy between the observed lack of surface warming in the eastern equatorial Pacific and climate model projections of an El Niño-like warming pattern confronts the climate research community. While anthropogenic aerosols have been suggested as a cause, the prolonged cooling trend over the equatorial Pacific appears in conflict with Northern Hemisphere aerosol emission reduction since the 1980s. Here, using CESM, we show that the superposition of fast and slow responses to aerosol emission change-an increase followed by a decrease-can sustain the La Niña-like condition for a longer time than expected. The rapid adjustment of Hadley Cell to aerosol reduction triggers joint feedback between low clouds, wind, evaporation, and sea surface temperature in the Southeast Pacific, leading to a wedge-shaped cooling that extends to the central equatorial Pacific. Meanwhile, the northern subtropical cell gradually intensifies, resulting in equatorial subsurface cooling that lasts for decades.

Highly Efficient Solar Steam Generation and Desalination through Gourd‐Flesh Templated Polypyrrole Composite

Solar steam generation (SSG) is regarded as a promising technique due to its potential in seawater desalination. Photothermal conversion materials derived from biomass are good evaporators for SSG because of their sustainability and high efficiency. Herein, 3D‐cylindrical‐structured composite materials based on gourd flesh and polypyrrole (GPPY) are designed and used for high efficient SSG. The polypyrrole layer is deposited on the gourd flesh to provide broad optical absorption ability and high photothermal conversion efficiency. In addition, gourd flesh with porous structure can act as thermal insulators, confine the generated heat within the evaporative surface, and facilitate the efficient transport of water to the photothermally active area. Based on these characteristics of the composite, the evaporator made of GPPY can achieve a high evaporation rate of (1.63 kg m−2 h−1), and a superior photothermal conversion efficiency 95.8% under 1 solar irradiation (1 kW m−2). The GPPY can be expected to be a practical photothermal conversion material for commercial SSG based on its high efficiency and sustainability.

Novel Natural Vacuum Membrane Distillation for water desalination: A combinational approach

Many methods have been proposed to produce fresh water utilizing solar and low-grade energy. The natural vacuum method is widely used despite its limitations in water production. The entry of non-condensable gases into the condenser reduces the amount of water production in the natural vacuum system. In addition, it requires a large evaporator surface to produce fresh water at a high rate. This research resolves these limitations for the first time by integrating the natural vacuum and membrane distillation methods, increasing the evaporation area in a small space, and creating a re-vacuum. Based on the results, the amount of water production for feed water with a salinity of 0.5 M, a flow rate of 60 L/h, and temperatures of 45, 65, and 85 °C reach 5.5, 18.5, and 45.9 m3/day for each square meter of the membrane by combining the methods above without creating a re-vacuum for 24-hour tests. Re-vacuum occurs in this novel system by pumping the saline water upward against the outlet valve and the existing membrane. When a re-vacuum occurs every 6 h, the amount of water production for feed water temperatures of 45, 65, and 85 °C increases approximately by 70 % for all feed water temperatures. However, energy consumption does not rise significantly due to employing a pump instead of a vacuum pump.

Weakened Increase in Global Near‐Surface Water Vapor Pressure During the Last 20 Years

AbstractIt is well known that global warming increases the atmospheric water vapor content, which results in substantial changes in the hydrological cycle. Using five observational data sets, the results show that an increasing trend of near‐surface water vapor pressure (AVP) over land and ocean was significant from 1975 to 1998, while such an increasing trend in AVP subsequently weakened from 1999 to 2019. This phenomenon is associated with decreased oceanic evaporation and land surface evapotranspiration in response to recent climate variations. One consequence of such a phenomenon is a large increase in near‐surface vapor pressure deficit (VPD), which in turn increases atmospheric demand for water vapor and thus aridity and drought over land. This result emphasizes the importance of water vapor change under global warming.

Biomimetic Structural Design of Fabric for Low‐Cost, Scalable, and Highly Efficient Off‐Grid Solar‐Driven Water Purification

AbstractInterfacial solar‐vapor generation (ISVG) is an emerging technology for water purification. However, high cost, low evaporation rate, clogging issues, and limited solar utilization under natural condictions greatly hinder its practical application. Herein, inspired by the aligned microstructure of dragonfly wings, a 3D microarray structure composed of vertically aligned hierarchical and hydrophilic carbon fibers (CFs) is constructed using a scalable fiber manufacturing technology. The microarray structure of the high‐thermal‐conductivity CFs with nanocapillaries contributes to the fast mass (steam and salt ions) and heat transfer as well as high omnidirectional light absorption. More importantly, due to the strong multiscale capillary effect, the formed 3D water evaporation surface containing abundant micro‐meniscuses and nanoscale thin water layers in the CFs arrays effectively reduces the evaporation enthalpy and creates more water/air interfaces, leading to the significant increasing evaporation rate. As a result, a high evaporation rate of 2.21 kg m−2 h−1 under one‐sun irradiation can be achieved. Moreover, the off‐grid water treatment device assembled with multiple 3D CFs‐based customized spherical evaporators can obtain a high pure water collection of 10.71 kg m−2 per day without salt accumulation under real environmental conditions. This work demonstrates a high‐efficiency, cost‐effective, and scalable strategy for high‐performance ISVG.

The Yin and Yang of non-immune and immune responses in meibomian gland dysfunction

Meibomian gland dysfunction (MGD) is a leading cause of dry eye disease and one of the most common ophthalmic conditions encountered in eye clinics worldwide. These holocrine glands are situated in the eyelid, where they produce specialized lipids, or meibum, needed to lubricate the eye surface and slow tear film evaporation – functions which are critical to preserving high-resolution vision. MGD results in tear instability, rapid tear evaporation, changes in local microflora, and dry eye disease, amongst other pathological entities. While studies identifying the mechanisms of MGD have generally focused on gland obstruction, we now know that age is a major risk factor for MGD that is associated with abnormal cell differentiation and renewal. It is also now appreciated that immune-inflammatory disorders, such as certain autoimmune diseases and atopy, may trigger MGD, as demonstrated through a T cell-driven neutrophil response. Here, we independently discuss the underlying roles of gland and immune related factors in MGD, as well as the integration of these two distinct mechanisms into a unified perspective that may aid future studies. From this unique standpoint, we propose a revised model in which glandular dysfunction and immunopathogenic pathways are not primary versus secondary contributors in MGD, but are fluid, interactive, and dynamic, which we likened to the Yin and Yang of MGD.

Novel Three-Dimensional Cut Umbrella-like Evaporator with Four Angle-Adjustable Evaporation Surfaces in a Submersible Floatation State for Enhanced Seawater Desalination

Novel Three-Dimensional Cut Umbrella-like Evaporator with Four Angle-Adjustable Evaporation Surfaces in a Submersible Floatation State for Enhanced Seawater Desalination