Maximum Evaporation Rate Research Articles

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

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

Fe3O4/Au@SiO2 nanocomposites with recyclable and wide spectral photo-thermal conversion for a direct absorption solar collector

The Fe3O4-based photothermal materials have been widely applied for the recycling of heavy metal nanoparticles to avoid secondary pollution in the utilization of solar energy owing to excellent magnetic properties. However, the narrow absorption band of Fe3O4 or metal nanoparticles limits their capacity for solar energy harvesting. In this paper, a recyclable and wide spectral photo-thermal conversion system (Fe3O4/Au@SiO2) based on Fe3O4 nanospheres and SiO2-modified Au nanorods (NRs) is prepared. Owing to the strong coupling effect between Fe3O4 and different Au NRs, the wide and strong absorption band from 400 nm to 1100 nm is obtained. Under the influence of magnetic field, the temperature change of nanofluids (NFs) at different positions can be controlled. When the concentration is 0.0467 vol%, the solar energy absorption fraction reaches 96.50 %. Besides, the photothermal performance of Fe3O4/Au@SiO2 NFs at different flow rates is investigated and the results show that temperature rise decreases as increasing flow rate. Finally, a water evaporator device based Fe3O4/Au@SiO2 NFs is developed. The maximum water evaporation rate of 2.6 kg m−2 h−1 can be reached and the movement of evaporator on water can be operated using magnetic field, showing great photothermal conversion performance and recovery potential in practical applications.

Preparation and characterization of potassium hydroxide activated hydrochar

This paper presents processing and characterization of hydrochar derived from bamboo via hydrothermal carbonization at 200 °C for 4 h followed by activation at 600 °C for 2 h. The hydrochar contains hierarchical pores. The BET surface area of the hydrochar activated by KOH reached 4.5506 m2/g. KOH enhanced pore and nanofiber formation. All the bamboo-derived hydrochars can effectively harvest solar energy to evaporate seawater. The KOH-activated one showed the best performance with the maximum evaporation rate of 3.057 kg/(m2∙h).

Fumed nano-silica modified PVA-chitosan composite hydrogel with Janus structure for solar-driven interfacial evaporation

Solar-driven interfacial evaporation (SIE) receives much attention nowadays. At present, efficient thermal management and salt resistance during operation are still the difficulties of SIE technology. In this work, a new composite hydrogel for SIE has been reported. This composite hydrogel uses polyvinyl acetate (PVA) and chitosan (CS) as the framework, carbon nanoparticles (CB) as the photothermal material, modified with hydrophilic/hydrophobic fumed nano-silica. The addition of fumed nano-silica reduces the thermal conductivity and effectively immobilizes heat energy on the evaporator’s top surface, which reduces heat loss and improves the evaporation rate. The CSPC (CB/Nano-silica PVA-CS) evaporator modified with hydrophobic nano-silica exhibits Janus structure with transition from a hydrophobic top to a hydrophilic bottom. The Janus-structured CSPC evaporator has the characteristics of excellent salt resistance, simple preparation process, low heat loss with self-floating property. The CSPC evaporator containing 0.5 g hydrophobic fumed nano-silica has a maximum evaporation rate of 1.58 kg/(m2·h), about 1.6 times higher than the evaporator without fumed nano-silica, which proves that the introduction of fumed nano-silica can effectively improve the evaporation performance of hydrogel. The overall efficiency of CSPC evaporator in simulated seawater is 88.63 %. The evaporation rate of CSPC evaporator has reached a high level in the evaporators using carbon black as photothermal material which was prepared by simple and low-cost method. It should be a promising category of material to be employed for solar desalination.

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.

Evaporation rate and kinetic mechanism of noble antimony under vacuum

Herein, a novel mathematical and statistical method is applied to the kinetic study of vacuum gasification of noble-antimony alloys. The evaporation rates of pure and noble antimony in a unit time at 823–1023 K and 5–600 Pa are determined using a vacuum differential gravimetric furnace, and their respective evaporation mechanisms under vacuum are analyzed in detail in conjunction with their triple point. Results show that the actual evaporation rates of pure and noble antimony are consistent with those obtained using a nonlinear logistic model (ω=A2+(A1-A2)/[1+P/P0a); the goodness of fit (R2) is > 0.9965 at all temperatures. The critical pressure values of pure and noble antimony at 823–1023 K are obtained, which are linearly dependent on the temperature. According to the theoretical and actual maximum evaporation rates of pure and noble antimony, the evaporation coefficient is corrected and the relation between the actual evaporation rate and temperature (lgω=AT+B) is further obtained, which can be used to calculate and predict the evaporation rates of noble antimony at different temperatures. By studying the evaporation rate of pure and noble antimony, this study provides the kinetic parameters for vacuum gasification of noble antimony and simultaneously enriches the kinetic database, which develops and improves the theory and practice of vacuum gasification of noble-metal alloys.

Vacuum evaporation and condensation thermodynamics and evaporation kinetics of pure silver

A comprehensive analysis of the characteristics of vacuum evaporation and condensation of pure silver is crucial for advancing vacuum separation and purification technology for crude silver. This study analyzes the vacuum evaporation and condensation thermodynamics and evaporation kinetics of pure silver. The results reveal a substantial increase in the saturated vapor pressure and theoretical maximum evaporation rate of pure silver with increasing temperature. When the temperature is in the range of 1373 ∼ 1773 K and the pressure is in the range of 0.1 ∼ 10 Pa, the average molecular free path is between 0.514 ∼ 66.415 cm. Moreover, the mean molecular free path of silver increases with increasing temperature and decreasing pressure. Besides, the silver triple point occurs at a temperature of 1234.78 K and a pressure of 0.343 Pa. The average evaporation rate of pure silver demonstrates a linear relationship with temperature, and the relationship with pressure conforms to the Logistic model. Notably, the vacuum evaporation of pure silver is a first-order reaction. Furthermore, in this study, the kinetic equation of vacuum evaporation of pure silver is established. In the temperature range of 1473–1673 K, the gas phase mass transfer is the rate-controlling step rather than the mass transfer in the gas phase boundary layer. As the temperature increases, the rate-controlling step gradually changes into gas relative flow mass transfer and gas-liquid interface evaporation mass transfer.

Efficient solar-powered evaporator with multifunctional nanofiber

Interfacial solar steam generation is acknowledged as an extremely effective and environmentally friendly method of producing potable water. Nevertheless, significant challenges persist in the development of an evaporator capable of achieving heightened rates of evaporation, catalytic capabilities, resistance to bacterial proliferation, and effective light absorption across a broad spectrum. This article outlines the fabrication of a solar steam generator utilizing electrospinning technology and membrane evaporators constructed from α-Fe2O3/PAN (polyacrylonitrile) nanofibers. The integration of α-Fe2O3/PAN composite enhances both light absorption and heat generation. In sunlight, the maximum evaporation rate is 2.7 kg m−2 h−1, which is significantly more than the rate of today's cutting-edge solution-electrospun nanofiber-based evaporators. The electrospun mat has high catalytic activity and antibacterial properties, making it an important component in desalination.

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.

Photothermal evaporation characteristics of magnetic rGO/Fe2O3 nanofluid droplets

The evaporation kinetics of magnetic nanofluid droplets under solar irradiation is important for their photothermal applications in energy and medicine areas. In this work, magnetic nanofluids were employed to study the evaporation kinetics including mass, temperature, and contact angle under solar irradiation. Compared with deionized water, the evaporation rate of magnetic nanofluid droplets was doubled and increased with the initial mass. At the beginning of evaporation, the evaporation rate reached the maximum value, and the stable evaporation stage was close to the end time. Moreover, the higher the light intensity was, the maximum evaporation rate appeared earlier and the stable evaporation time was shortened. At the same time, the higher the extreme value of the evaporation rate, the faster the rate of decline, and the shorter the evaporation time, when the light intensity was higher than 800 W/m2, the rate does not change significantly. This interfacial evaporation technology of magnetic nanofluid droplets offers great convenience to liquid and droplet handling and may be implemented in a multitude of domains such as bio-sensing, chemistry combination, and solar catalytic fuel production.

Wetting, droplet evaporation and corrosion behavior of various composite and textured materials

Experimental studies were conducted on the evaporation rate of a droplet located on the surfaces of various composite and textured materials with different wettability at varying surface temperatures. The maximum droplet evaporation rate was recorded on a textured Cu–SiC composite material with superhydrophilic properties. The minimum droplet evaporation rate corresponded to a superhydrophobic AlMg3 substrate obtained using laser texturing with subsequent hydrophobization procedure. An increase in surface temperature led to a significant deterioration of hydrophobicity for a superhydrophobic substrate and a deterioration of hydrophilicity for a superhydrophilic substrate. As a result, with increasing temperature, the influence of the droplet geometry determined by surface wettability on the droplet evaporation rate for these substrates sharply decreases. Advancing and receding dynamic contact angles, as well as contact angle hysteresis were obtained on all studied substrates. It is generally accepted that a hydrophobic surface exhibits less contact angle hysteresis than a hydrophilic one. However, Cu-SiС composite substrate with a textured hydrophobic surface exhibited the opposite behavior. The contact angle hysteresis on the hydrophobic textured surface was found to be four times higher than that on the hydrophilic polished one. A mechanism was proposed that explains the high contact angle hysteresis and four hysteresis time modes. The minimum hysteresis value corresponded to the superhydrophobic AlMg3 substrate. Anti-corrosion properties were studied for all substrates under consideration. The minimum corrosion current corresponded to a copper substrate with a graphene coating, as well as a superhydrophobic AlMg3 substrate. For a given substrate, there are two corrosion modes with a three-fold difference in the corrosion current. In addition, the wettability behavior of different surfaces was examined using molecular dynamics simulations. The simulation results were found to be consistent with the experimental data.

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.

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.

Multicompartmental coacervate-based protocell by spontaneous droplet evaporation

Hierarchical compartmentalization, a hallmark of both primitive and modern cells, enables the concentration and isolation of biomolecules, and facilitates spatial organization of biochemical reactions. Coacervate-based compartments can sequester and recruit a large variety of molecules, making it an attractive protocell model. In this work, we report the spontaneous formation of core-shell cell-sized coacervate-based compartments driven by spontaneous evaporation of a sessile droplet on a thin-oil-coated substrate. Our analysis reveals that such far-from-equilibrium architectures arise from multiple, coupled segregative and associative liquid-liquid phase separation, and are stabilized by stagnation points within the evaporating droplet. The formation of stagnation points results from convective capillary flows induced by the maximum evaporation rate at the liquid-liquid-air contact line. This work provides valuable insights into the spontaneous formation and maintenance of hierarchical compartments under non-equilibrium conditions, offering a glimpse into the real-life scenario.

Modeling of Impurities Evaporation Reaction Order in Aluminum Alloys by the Parametric Fitting of the Logistic Function.

Advancements in computer capabilities enable predicting process outcomes that earlier could only be assessed after post-process analyses. In aerospace and automotive industries it is important to predict parts properties before their formation from liquid alloys. In this work, the logistic function was used to predict the evaporation rates of the most detrimental impurities, if the temperature of the liquid aluminum alloy was known. Then, parameters of the logistic function were used to determine the transition points where the reaction order was changing. Samples were heated to 610 °C, 660 °C, 710 °C, and 760 °C for one hour, after which the chemical analyses were performed and evaporation rates were calculated for Cd, Hg, Pb and Zn elements. The pressure inside the encapsulated area was maintained at 0.97 kPa. Whereas parameters that define the evaporation rate increase with the temperature increase, the maximum evaporation rates were deduced from the experimental data and fitted into the logistic function. The elemental evaporation in liquid-aluminum alloys is the best defined by the logistic function, since transitions from the first to zero-order-governed evaporation reactions have nonsymmetrical evaporation rate slopes between the lowest and the highest evaporation rate point.

Constructing salt-resistant 3D foams with hierarchical interconnected channels by vacuum casting method for efficient solar evaporation of hypersaline water

Solar interfacial water evaporation is an environmentally friendly and potential approach to producing fresh water. Herein, a PAN/CNTs-foam (PCF) evaporator with high porosity, hierarchical pore structure, and excellent solar absorption was successfully prepared by the vacuum casting method. The PCF prepared with a CNTs content of 17 % and NaCl particle size of 150–300 μm possessed an evaporation rate of 2.04 kg m−2 h−1 for pure water under 1 sun illumination. The PCF-2 showed a maximum evaporation rate of 5.60 kg m−2 h−1 for real seawater in outdoor experiments, and the quality of the produced clean water was also demonstrated. The purification ability of PCF for organic dyes further confirmed the potential usage in wastewater treatment. Particularly, the PCF-2 exhibited efficient and stable desalination performance for hypersaline water even in 25 wt% simulated brine due to the hierarchical interconnected channels. Our work offers a robust method for the construction of a 3D foam evaporator with hierarchical interconnected channels for efficient and sustainable hypersaline water desalination.

Upcycled graphene nanoplatelets integrated fiber-based Janus membranes for enhanced solar-driven interfacial steam generation

Upcycled GNP derived from the pyrolysis of waste tires is used as a photothermal material. Finding the optimum GNP content for minimum cost and maximum evaporation rate can enhance the techno-economic aspect of the developed Janus membranes.

Laminated chitosan/graphene nanoplatelets aerogel for 3D interfacial solar desalination with harnessing wind energy

Interfacial solar steam generation (ISSG) is a novel approach to freshwater generation. In practical utilization of new ISSG technology, achieving high evaporation rate is a crucial step. A three-dimensional (3D) solar absorber can increase the exposed surface area and enhance the escape of water molecules to the surrounding environment. However, vigorous evaporation induces to dry out the evaporator quickly, leading to damage its structure or decreased efficiency. In this context, a transversely laminated aerogel-based 3D evaporator is proposed. For this, chitosan/graphene nanoplatelets (CG) are incorporated to create laminated CG (LCG) aerogels having two different densities in a single structure. The results demonstrate that LCG aerogels exhibit rapid water-rise ability and excellent solar absorption characteristics. The laminated structure enhances mechanical strength and maintains balanced water and ion gradients sustainably, inducing a wettable and evaporation-enhanced condition. With these advantages, the evaporation rate of LCG aerogels with aspect ratio (AR) of 7 achieves 2.17 kg m−2h−1. In addition, evaporation experiments were conducted by applying precisely-controlled wind in a wind tunnel to the 3D evaporator. At a wind speed of 6 m s−1, the proposed evaporator achieves a maximum evaporation rate of 5.98 kg m−2h−1. Aerogel with a single density is better suited for situations where only solar radiation is present, while the LCG aerogel, which can utilize the features of two densities at the same time, is more effective in windy conditions. The evaporation efficiency is over 73 % for seawater and 20 wt% high-concentration NaCl solution, showing excellent durability with salt-resistance. The proposed aerogel-based evaporators would be utilized as a sustainable seawater desalination technology for environmentally friendly freshwater production.

Evaporation and heat exchange of a thin liquid layer under various heating methods: Advantages of local heating over uniform heating of the wall

Intensification of heat transfer and evaporation is widely used in modern technologies at limited dimensions of heat exchange surfaces and high energy density. To date, stationary heat transfer at uniform wall heating, has been most thoroughly investigated. Meanwhile, there is no comprehensive research providing a comparison of free convection, heat transfer and evaporation with different heating methods. The novelty of the work lies in the comparison of the heat transfer efficiency using one laser beam, two beams and homogeneous heating. When heated by a single laser beam, the average temperature of the layer interface is significantly lower than at homogeneous heating. However, due to the generation of intense Marangoni flow, a small heating spot provides more intense evaporation than homogeneous heating. The effectiveness of heat transfer is analyzed in terms of the total efficiency coefficient. If it is important to take into account power input, it is preferable to use a single laser beam. If it is not decisive, then two laser beams allow achieving maximum heat transfer and evaporation rate. Homogeneous heating is significantly inferior to local non-stationary heating in terms of all key criteria. The simple expressions serve to optimize the total efficiency coefficient.

Numerical Study on Heat and Mass Transfer of Evaporated Binary Zeotropic Mixtures in Porous Structure

This study investigates the heat and mass transfer characteristics of a binary mixture (R134a/R245fa) evaporated in a porous medium. The Eulerian model coupled with the multiphase VOF model and species transport equations is employed to establish a multi-component evaporation model. The effects of heat flux ranging from 200 kW/m2 to 500 kW/m2, porosity ranging from 0.4 to 0.6, and mass fraction ratios (R134a/R245fa) of 3:7, 5:5, and 7:3 are explored. The results indicate that an increase in heat flux contributes to an increase in the evaporation rate. For the overall evaporation rate, the evaporation rates of R134a and R245fa improve by 11.3%, 6.9%, and 16.3%, respectively, while the maximum improvement in heat transfer coefficient is only 1.4%. The maximum evaporation rate is achieved at intermediate porosity in the porous medium, and the highest heat transfer coefficient is obtained at a porosity of 0.4. With the increase in mass fraction, the evaporation rate of the corresponding species also increases, while the overall evaporation rate and heat transfer coefficient remain almost unchanged.