Concentrated Salt Solutions Research Articles

Tailoring amino-functionalized n-alkyl methacrylate ester-based bio-hybrids for adsorption of methyl orange dye: Controllable macromolecular architecture via polysaccharide-integrated ternary copolymerization.

Controllable macromolecular architecture formation via polysaccharide integrated ternary copolymerization was explored in the design of amino-functionalized n-alkyl methacrylate ester-based biohybrids. Ternary poly(dimethylaminoethyl methacrylate-co-glycidyl methacrylate-co-hydroxypropyl methacrylate)/sodium-alginate, PDGH/ALG, hybrids were designed using anionic polysaccharide through in-situ radical polymerization. An insight into the effect of ALG on physicochemical structure of ternary hybrids, particularly the interactions between polymeric chains, was created. In addition to incorporation of ALG, the effect of polymerization under cryocondition on mechanical stiffness of hybrids was investigated. Adding 0.5 % ALG to ternary PDGH matrix resulted in a 4.2-fold increase in compressive modulus. Swelling of hybrid hydrogels prepared at 1 °C decreased by 5 times, while a 3.4-fold decrease was observed in hybrid cryogels formed at -18 °C. ALG-rich hybrids showed "salting-in" behavior with increasing salt concentration in NaCl, KCl and MgCl2 solutions, while hybrids with low ALG-content exhibited "salting-out" behavior. The hybrid gels were applied to adsorption of anionic dye methyl orange (MO) from simulated dye wastewater. The adsorption was found to follow Freundlich mechanism and a pseudo-second-order kinetic model. ALG-integrated hybrid gels showed a high desorption efficiency and a longer lifespan during the regeneration process, thus showing potential to be used for anionic dye removal from textile wastewater in industry.

Quantification of vehicular versus uncorrelated Li+-solvent transport in highly concentrated electrolytes via solvent-related Onsager coefficients.

Highly concentrated salt solutions are promising electrolytes for battery applications due to their low flammability, their high thermal stability, and their good compatibility with electrode materials. Understanding transport processes in highly concentrated electrolytes is a challenging task, since strong ion-ion and ion-solvent interactions lead to highly correlated movements on the microscopic scale. Here, we use an experimental overdetermination method to obtain accurate Onsager transport coefficients for concentrated binary electrolytes composed of either sulfolane (SL) or dimethyl carbonate (DMC) as solvent and either LiTFSI or LiFSI as salt. NMR-based electrophoretic mobilities demonstrate that volume conservation applies as a governing constraint for the transport. This fact allows to calculate the Onsager coefficients σ+0, σ-0 and σ00 related to the solvent. A parameter γ is then defined, which is a measure for the relevance of a vehicular Li+-solvent transport mechanism. We analyze the influence of the salt anion and of the solvent on dynamic correlations and transport mechanisms. In the case of the sulfolane-based electrolytes, the γ parameter reaches values up to 0.38, indicating that Li+-sulfolane interactions are stronger than Li+-anion interactions and that vehicular Li+-sulfolane transport plays a significant role. In the case of DMC-based electrolytes, the γ parameter is close to zero, suggesting balanced Li+-DMC vs. Li+-anion interactions and virtually uncorrelated movements of Li+ ions and DMC molecules.

Non-ionic surfactant self-assembly in calcium nitrate tetrahydrate and related salts.

Self-assembly of amphiphilic molecules can take place in extremely concentrated salt solutions, such as inorganic molten salt hydrates or hydrous melts. The intermolecular interactions governing the organization of amphiphilic molecules under such extreme conditions are not yet fully understood. In this study, we investigated the specific effects of ions on the self-assembly of the non-ionic surfactant C12H25(OCH2CH2)10OH (C12E10) under extreme salt concentrations, using calcium nitrate tetrahydrate as a reference. The mixtures of Ca(NO3)2·4H2O and C12E10 displayed lyotropic (H1 and I1) and micellar phases, in contrast to CaCl2·xH2O-C12E10 or CaBr2·xH2O-C12E10 mixtures where mesostructurally ordered salt-surfactant complexes were observed. The Ca(NO3)2·4H2O-C12E10 system was thoroughly investigated by constructing its binary phase diagram and performing thermal and spectral comparisons with other salt hydrates. The Ca(NO3)2 system displayed significantly higher isotropization temperatures than zinc, aluminium, and lithium nitrate systems. ATR-FTIR analysis revealed that Ca2+ primarily interacts with the surfactant head groups through ion-dipole interactions, while these interactions were less pronounced with other cations. The results show that an intermediate hydration/coordination energy of the metal ion can lead to stronger metal-surfactant interactions and thermally more stable liquid crystals. Comparison between the Ca(NO3)2, CaCl2, and CaBr2 systems suggests that reduced ion pair formation enhances the interactions between Ca2+ and oxyethylene groups, leading to the salting-out of salt-surfactant complexes. Despite its low water content and strong intermolecular interactions, the Ca(NO3)2·xH2O-C12E10 system exhibited an electrical conductivity of up to 1.0 × 10-3 S cm-1 with 4 water molecules per salt, making it a promising medium for electrochemical applications.

Efficient capture of 99TcO4-/ReO4- via node and linker bifunctional anion exchange covalent organic frameworks.

In nuclear wastewater treatment, ion-scavenging materials designed to trap 99TcO4- is urgently needed. However, strong acid/base, high radiation and high salt concentration of nuclear wastewater usually result in inadequate stability and adsorption capacity of the adsorbent. Herein, we report a new class of bifunctional anion-exchange olefin-linked COF (BPDC-MTMP) prepared via Knoevenagel condensation reactions, the first example exploring the synergistic integration of positively charged fragments at both nodes and linkers. Surprisingly, BPDC-MTMP exhibits a record ReO4- (a non-radioactive surrogate of 99TcO4-) adsorption capacity up to 1593.21 mg g-1, its outstanding adsorption capacity can be attributed to the synergistic enhancement of the positively charged fragments of the nodes and linkers leading to a significant increase in the positive charge density and the number of anion exchange sites. BPDC-MTMP's hydrophobicity is enhanced by the highly conjugated bulky alkyl skeleton, the affinity toward ReO4- and chemical stability are therefore significantly improved, ReO4- can be selectively and reversibly extracted even under strong acid/base and high salt concentration solutions. This study illustrates that the node and linker bifunctional anion exchange COF is of great potential for ReO4-/99TcO4- trapping, which provides a new method to design high-performance adsorbents for the treatment of nuclear wastewater.

Production of active chlorine and sodium hypochlorite in a closed electrolyser

Today, in the conditions of warfare, there is constant local pollution of the environment due to the use of explosives, fires, spillage of fuel and lubricants, etc. Every day, the danger increases when the water drainage systems of various enterprises are damaged, such as mining enterprises, facilities of the energy, metallurgy, chemical, petrochemical industries, sludge storage facilities for highly toxic waste. Next to this, there is a growing problem of highly efficient purification of water, primarily drinking water. As a result of the destruction of the Kakhovsky reservoir in 2023, the problem of disposal of mine waters, which are characterized by a high level of mineralization, a significant content of iron, manganese and other toxicants, has sharply worsened. In this case, there are no water resources for diluting mine waters before their discharge. Despite a significant number of developments in the field of water quality control and water purification technologies, a number of problems in this direction remain unresolved. Existing technologies are ineffective when the levels of mineralization and water hardness are exceeded. We are talking about the southern regions of our country and Donbas. In Mykolaiv, after the aggressor reduced the water intake on the Dnieper, the centralized water supply system supplies brackish water from the estuary. It is known that concentrated salt solutions, which are formed and are still present next to the problems described above, are practically not processed. In most cases, they are dumped into the surface reservoirs of the surrounding natural environment, which significantly worsens the state of water ecosystems of Ukraine. The situation is worsened by the fact that a significant part of mine water suitable for use, due to the problem of disposal of concentrates, is not used, but is discharged into the environment after dilution, or even without dilution and purification, since there is simply no resource for dilution in today's realities. That is why, the problem of processing concentrates of baromembrane purification with obtaining secondary useful products was the aim of the research of this work.

Determination of Tetrodotoxin in Miso Soup byStrong Cation Exchange Solid Phase Extraction and LC-MS/MS

A method for analyzing tetrodotoxin (TTX) in miso soup samples was proposed. The samples were purified using strong cation exchange solid-phase extraction and analyzed by liquid chromatography-tandem mass spectrometry. The recovery of TTX was considerably influenced by the salt concentration in the loading solution during purification. It was observed that diluting the loading solution to reduce the salt concentration helped to maintain the recovery rate during the washing step. However, during the loading step, the benefit of dilution in improving recovery was not evident, as the enhanced retention on the solid phase caused by dilution was counteracted by losing TTX with the increased volume of the loading solution, which led to enhanced elution. This suggests that the volume of extraction solution used in the loading process is crucial in determining the recovery rate. Additionally, the use of volatile ammonium acetate as the elution solvent was explored to optimize conditions for effective recovery. Testing this method on miso soup samples with varying miso types, salt concentrations, and TTX levels resulted in consistently high recovery rates of>80%.

On a Specific Method for Characterizing Ion Exchange Membranes to Assess Their Functionality in Salinity Gradient Power Generation Through Reverse Electrodialysis, Including the Effect of Temperature.

Salinity gradient power (SGP) by reverse electrodialysis is a promising method for converting SGP into electricity. Instead of the conventional approach of using seawater and freshwater, an alternative method involves using highly concentrated salt solutions (brines) alongside seawater or brackish water. Key factors influencing SGP via reverse electrodialysis (SGP-RE) include the properties of ion exchange membranes, particularly their thickness. This paper outlines a practical experimental set-up that uses both a cation membrane (CM) and an anion membrane (AM). The system is configured with three compartments: two outer compartments filled with highly concentrated brine (HIGH) and a central compartment containing a lower concentration salt solution (LOW), akin to seawater. The compartments are separated by a CM on one side and an AM on the other. The ion transport rate from the HIGH compartments to the central LOW compartment allows for determining the overall ion transport coefficient for thin membranes. Measurements of ion flux and electrochemical voltage under dynamic equilibrium conditions also enable the estimation of the SGP-RE power density (W/m2). By controlling the temperature of the HIGH and LOW solutions, this experiment further investigates the significant impact of temperature on ion transport characteristics.

Karakteristik Mutu Pikel Jahe dengan Penambahan Ekstrak Bawang Dayak

Processing ginger into pickles can provide added economic value and potentially become an export commodity. Ginger pickles are made by soaking ginger slices in a salt solution. Improving the quality of elephant ginger pickles can be done by adding natural dyes to have a pink color like Gari. Dayak onion extract can be used as a natural dye. This research aimed to determine the quality characteristics of ginger pickle with the addition of Dayak onion extract to the soaking medium at 7 dan 14 fermentation days and compare it with a salt solution soaking medium of various concentrations. This study is experimental research that used a Completely Randomized Design consisting of 6 treatments, namely a water-based and a Dayak onion extract-based soaking solution, each made with 5%, 7%, and 9% (w/v) salt concentration. The results showed (1) Adding Dayak Onion extract and variations of salt concentration in elephant ginger pickles had a significant effect on pH, and TPT and had no significant effect on the color and number of lactic acid bacteria); (2) Ginger pickles with a water-based 7% concentration salt solution (P2) most preferred treatment by the panelists.

The Effect of NaCl-Salinity Applications on the Improvement of Quality Characteristics and Yield of Tomato (Lycopersicon esculentum L.) Grown in Substrate Culture

Salt application in soilless cultivation systems can be considered as a strategic tool to improve tomato fruit quality. In this context, the effects of increasing the salt concentration in the nutrient solution added to the solid culture medium on yield and yield components, biophysical and organoleptic quality traits of tomato (Lycopersicon esculentum L. cv. Kardelen F1) under greenhouse conditions were studied. The salt in the nutrient solution was applied to tomato plants as sodium chloride (NaCl) at four concentrations (0, 14.1, 44.4, and 70.4 mM). Each pot received 150 mL of nutrient solution daily during the vegetative period, while 300 mL was applied daily after flowering. This study was conducted with three replicates following a randomized block design. Plants were harvested 90 days after transplanting. Low salt application in the nutrient solution (14.1 mM NaCl) increased total fruit yield, while the high salt application did not effect fruit yield compared to the control. Salt application at increasing concentrations decreased fruit size and diameter but increased the dry matter in the fruit. The salt treatment mainly positively affected the commercial and organoleptic quality parameters of the tomato fruits. In conclusion, a low level of sodium chloride (14.1 mM NaCl) in soilless culture enhanced fruit production, while moderate (44.4 mM) and high (70.4 mM) concentrations improved various fruit quality traits.

Evaluation of H2O2, H2, and bubble temperature in the sonolysis of water and aqueous t-butanol solution under Ar: Effects of solution temperatures and inorganic additives of NaCl and KI

The yields of H2O2 and H2 formed in the sonolysis of aqueous solution under noble gas are representative indexes for understanding the chemical effects of ultrasonic cavitation bubbles. In this study, the yields of H2O2 and H2 formed under Ar were evaluated as a function of the concentration of NaCl or KI. When these yields were analyzed by using a normalization technique, it was confirmed that the yields of H2 were more clearly related to Ar solubility than those of H2O2, suggesting that H2 is a more real probe to understand the chemical effects of cavitation bubbles in water. The effects of NaCl on sonochemical formation of oxidants were also compared with those of KI. When aqueous t-butanol solution was sonicated, the yields of H2 and the maximum temperature attained in a collapsing bubble (bubble temperature) decreased with increasing solution temperature and salt concentration, suggesting that these parameters affected the quantity related to the number (and/or size) of active bubbles as well as the quality related to the bubble temperatures.

Performance Analysis of Air Gap Membrane Distillation Process Enhanced with Air Injection for Water Desalination.

Water scarcity is a global issue, and desalination is an alternative to providing fresh water. Renewable energies could be used in thermal desalination to produce freshwater from high saline concentration solutions. In this paper, the experimental performance of an air-injection-Air Gap Membrane Distillation (AGMD) module is presented. The effect of the operation parameters (saline solution temperature, air flow, and salt concentration) on the distilled water rate was evaluated. The air injection enhanced the distilled water rate by 22% at the highest air flow and a solution flow rate of 80 °C, compared to the conventional condition (without air injection) at a salt concentration of 100,000 ppm. Under the same operating conditions, the increase was 17% at a salt concentration of 70,000 ppm. The maximum distilled water rate was 14.10 L/m2·h at 80 °C and an airflow of 1.5 L/min with the highest salt concentration, while it was also 14.10 L/m2·h at the lower salt concentration was 14.10 L/m2·h. The distilled water quality also improved as the air flow increased, since a conductivity reduction of 66% was observed. With the described mathematical model, 94% of the calculated values fell within ±10% of the experimental data for both salt concentration conditions.

Utilization of moringa leaf flour (Moringa oleifera) in making soy sauce

Abstract Soy sauce, a widely used condiment, is typically produced from soybeans and wheat. However, there is increasing interest in improving its nutritional and sensory properties through the use of alternative ingredients. This study explores how varying concentrations of moringa leaf flour and salt solution affect the quality characteristics of soy sauce. Employing a completely randomized factorial design, the research focused on two main factors: the percentage of moringa leaf flour (0%, 10%, 20%, 30%) and different salt solution concentrations (18%, 22%, 26%). Key parameters assessed included color index, pH, total soluble solids, viscosity, and various sensory characteristics. Results indicated that the concentration of salt has a significant effect on pH, total soluble solids, carbohydrates, and sensory attributes. Furthermore, the concentration of moringa leaf flour was found to significantly influence pH, total soluble solids, fat, protein, carbohydrates, color index, and sensory qualities like color, aroma, and flavor. The interaction between salt and moringa leaf flour also impacted pH, color index, carbohydrates, and overall sensory acceptability. The best quality soy sauce was achieved with a combination of 30% moringa leaf flour and 22% salt solution. This innovative soy sauce is anticipated to contribute positively to a healthier and more sustainable food industry.

Effect of Chloride Solution on Liquid Limit, and Plasticity Index of Soil in Selected Sites in Erbil /North Iraq

This study is an attempt to investigate the effect of NaCl, CaCl2, KCl, and NH4Cl solutions with different concentrations (2.5%, 5%, 7.5%) on the liquid limit, plastic limit, and plasticity index of Sarbasty and Mamwastayan soil samples /Erbil Governorate. The soil samples' liquid and plastic limits were found by using the cone penetrometer method. The Results showed that the soil's liquid, plastic limits, and Plasticity index decreased with increasing salt solution concentration. Maximum reduction of liquid limit and plastic limit in Sarbasty was from 53.6 to 34.3 and in Mamwastayan from 35.9 to 27.2, both accomplished by adding a concentration of 7.5% of KCl and CaCl2 respectively. According to the Unified Soil Classification System, the Sarbasty soils were classified as high plasticity clay (CH), and Mamwastayan low plasticity clay (CL). After adding different concentrations of salt solution to the soil, the Sarbasty soil classification changed from CH to CL. Mineralogically these soils are composed of non-clay minerals of calcite and quartz and clay minerals consisting of Montmorillonite, Chlorite, swelling Chlorite, Kaolinite, Illite, Palygorskite, and Illite- Chlorite. Sarbasty soil was the most effective salt chloride solution than the Mamwastayan soil sample swelling.

Experimental study and analysis of the static and dynamic mechanical properties of graphene oxide cement soil under composite salinity erosion

In coastal and saline-alkali regions, cement soil materials face significant challenges from salt erosion and both dynamic and static loads, threatening their structural stability. To enhance the mechanical properties of cement soil, this study explores the incorporation of graphene oxide (GO). We subjected GO cement soil specimens to various concentrations of a composite salt solution (with a NaCl to Na2SO4 mass ratio of 1:1) in erosion experiments lasting 7 and 30 days. The specimens were analyzed through unconfined compressive strength tests, split Hopkinson pressure bar (SHPB) tests, and scanning electron microscopy (SEM) to examine changes in stress-strain curves, peak stress, and energy dissipation. The results indicate that the dynamic and static peak stresses, energy absorption, and energy absorption efficiency of the GO cement soil specimens are inversely related to the concentration of the mixed salt solution. Notably, in a 4.5 g/L erosion environment after 7 days, an increasing trend was observed in static peak stress, energy absorption, and energy absorption efficiency. Additionally, when the salt concentration was fixed, these properties showed a positive correlation with impact gas pressure. SEM analysis revealed that the nucleation effect of GO and its strong bonding with the cement matrix significantly improved the microstructure of the specimens by reducing pores and defects, thus enhancing density and overall performance. Furthermore, in an 18 g/L erosion environment, a notable presence of ettringite (AFt) was identified in the GO cement soil specimens.

Preparation, characterization, and stability of chitosan-tremella polysaccharide layer-by-layer encapsulated astaxanthin nanoemulsion delivery system

In this study, a layer-by-layer (LBL) encapsulated astaxanthin (Ast) nanoemulsion delivery system based on chitosan (CS) and tremella polysaccharide (TP) was successfully developed. The system constructed an Ast-CS-TP emulsion with high encapsulation efficiency and an excellent stability profile by utilizing the opposite charge properties of CS and TP. This study evaluated the effects of different stresses (including temperature, salt addition, pH, UV irradiation, and centrifugal force) on the emulsion's stability. To further investigate the protective mechanism of the emulsions, we performed antioxidant activity experiments after UV treatment. Additionally, an in vitro digestion experiment was conducted to assess the behavior of Ast emulsion under simulated gastrointestinal conditions. The stability correlation coefficients were calculated using the Python database Pandas. The results showed that Ast-CS-TP emulsions exhibited turbidity and enhanced homogeneity with a small particle size of around 400 nm and a high absolute zeta potential of 35 mV and exhibited excellent stability under various stresses. The Ast-CS-TP emulsions also exhibited pH-responsive release at pH ≥ 7, consistent with pH changes in the gastrointestinal tract, and were stable in highly concentrated salt solutions. We found that the CS and TP layers significantly improved the photostability of Ast. CS and TP significantly enhanced Ast's oral bioavailability. The stability correlation coeffcients showed that pH and salt concentration were the largest factors that affected the stability of the emulsion. This study provided important insights into the encapsulation and targeting of Ast, providing a theoretical foundation and technical guidance for the comprehensive utilization of Ast.

Influence of Salt Concentration and Type on Dielectric Permittivity of Rocks

Summary Ionic properties and concentration significantly influence the response of brine-saturated rocks to electromagnetic disturbance. However, the dielectric permittivity response of rocks under different ionic conditions is poorly described. This significantly limits the potential information that could be gained from dielectric permittivity measurements about the pore geometry and fluid content. The influence of salt concentration and type on broadband dielectric permittivity must be reliably quantified to enhance interpretation of dielectric permittivity measurements. The main objective of this paper is to quantify the influence of salt type and concentration on dielectric permittivity via experimental measurements and pore-scale simulations. We examine the impact of salt concentration and type on the dielectric permittivity of pore- and core-scale Berea sandstone (BS) samples. First, we perform frequency-domain dielectric permittivity simulations to quantify the response of the pore-scale models to electric field excitation. The frequency-domain dielectric permittivity simulator solves Maxwell’s equations under quasistatic conditions at discrete frequencies. We simulate the dielectric permittivity in the frequency range of 20 MHz to 3 GHz. We perform the simulations in samples saturated with NaCl, KCl, and MgCl2 brines. The salt concentration of the brine solutions ranges between 10 PPT and 100 PPT (parts per thousand). We fully saturate the samples with different brine solutions at varying salt concentrations for the core-scale analysis. In the core-scale domain, we use the brine solutions and salt concentrations assumed in the pore-scale analysis. The dielectric permittivity measurements were conducted using a network analyzer with a high-temperature coaxial probe setup in the frequency range of 300 MHz to 3 GHz. We observed that relative permittivity at 1 GHz increases with increasing salt concentration, irrespective of the brine type. However, the type of salt significantly controls the magnitude of the decrease in relative permittivity. After increasing the salt concentration from 10 PPT to 100 PPT, relative permittivity at 1 GHz increased by 11% and 7% when the samples were saturated with KCl and NaCl brine solutions, respectively; at 20 MHz, the same increase in salt concentration caused rock relative permittivity to increase by only 1% and 5% in the samples saturated with KCl and NaCl brines, respectively. The lower sensitivity of relative permittivity to salt concentration at 20 MHz compared to 1 GHz can be attributed to the combined influence of interfacial and orientational polarizations on rock dielectric permittivity. The impact of salt type on relative permittivity was negligible in samples saturated with 10 PPT brine solutions. Results demonstrated that taking the influence of salt concentration and type into account is critical for reliable interpretation of dielectric permittivity measurements. The novel contribution of this work is the documentation of how the saturating brine type influences the complex dielectric permittivity of the rocks. This work illuminates the extent to which the relative permittivity can be used for petrophysical analysis in cases where the formation brine salt concentration is uncertain. Additionally, the outcomes of this work will contribute to enhanced interpretation of dielectric permittivity measurements in formations with variable salt concentrations of formation water.

Phosphate-Driven Interfacial Self-Assembly of Silk Fibroin for Continuous Noncovalent Growth of Nanothin Defect-Free Coatings.

Silk fibroin is a fiber-forming protein derived from the thread of Bombyx mori silkworm cocoons. This biocompatible protein, under the kosmotropic influence of potassium phosphate, can undergo supramolecular self-assembly driven by a random coil to β-sheet secondary structure transition. By leveraging concurrent nonspecific adsorption and self-assembly of silk fibroin, we demonstrate an interfacial phenomenon that yields adherent, defect-free nanothin protein coatings that grow continuously in time, without observable saturation in mass deposition. This noncovalent growth of silk fibroin coatings is a departure from traditionally studied protein adsorption phenomena, which generally yield adsorbed layers that saturate in mass with time and often do not completely cover the surface. Here, we explore the fundamental mechanisms of coating growth by examining the effects of coating solution parameters that promote or inhibit silk fibroin self-assembly. Results show a strong dependence of coating kinetics and structure on solution pH, salt species, and salt concentration. Moreover, coating growth was observed to occur in two stages: an early stage driven by protein-surface interactions and a late stage driven by protein-protein interactions. To describe this phenomenon, we developed a kinetic adsorption model with Langmuir-like behavior at early times and a constant steady-state growth rate at later times. Structural analysis by FTIR and photoinduced force microscopy show that small β-sheet-rich structures serve as anchoring sites for absorbing protein nanoaggregates, which is critical for coating formation. Additionally, β-sheets are preferentially located at the interface between protein nanoaggregates in the coating, suggesting their role in forming stable, robust coatings.

Effect of salt solution concentration and cation types on the mechanical properties of bentonite as a barrier material

Effect of salt solution concentration and cation types on the mechanical properties of bentonite as a barrier material

Tough, antimicrobial, recyclable hydrogel with tree-trunk-inspired core‐sheath structure for efficient all-day desalination

Solar-driven interfacial evaporation, an economically friendly freshwater harvesting technology, faces the challenge of achieving efficient all-day desalination. Inspired by the core‐sheath structure of tree trunks, herein, a hydrogel evaporator features internal vertical lamellar sodium alginate (SA) pores supported by aramid fiber (AF) networks and surface covered with a dense layer of copper sulfide (CuS) and was fabricated through freeze-drying-cycling alternating immersion method. The internal vertical SA lamellar structure endows the hydrogel with strong water transport capability, while the high photothermal conversion ability of the surface CuS layer enables rapid water evaporation. Therefore, as 2D evaporators, the evaporation rate in highly concentrated salt solutions (15 wt%) is up to 2.07 kg m-2 h-1 under 1.0 sun. As 3D evaporators, efficient evaporation is achieved throughout the day by compensating evaporation at the sides and top. Under the irradiation of 0.2 and 0.8 suns outdoors, the evaporation rate of the 3D evaporator can reach 7.47 kg m-2 h-1 and 12.60 kg m-2 h-1, respectively, and its total evaporation is 4.72 times higher than that of the 2D evaporator. Notably, the hydrogel evaporator has excellent anti-salt properties, antimicrobial properties, and recyclability. This work provides valuable guidance for designing and developing practical hydrogel evaporators.

An Electrically Small Patch Antenna Sensor for Salt Concentration Measurement of NaCl Solution.

In this paper, a complementary split-ring resonator (CSRR)-based patch antenna is proposed as a microwave sensor to measure the salt concentration of NaCl solution. The microwave sensor consists of an RF-4 substrate, where a small copper disc is attached on the top as the radiator, a larger copper disc integrated with two CSRRs is attached on the bottom side as the finite ground plane, and a coaxial feeding port is introduced at the ground plane center. During salt concentration sensing, only the top disc is immersed into NaCl solution. The results indicate that the proposed microwave sensor can measure salt concentrations ranging from 5‱ to 35‱ with a maximum sensitivity of 0.367 (kHz/(mg/L)). The proposed microwave sensor is low-cost, low-profile, electrically small, lightweight, and easy to fabricate, and it also can be applied to other solutions' concentration sensing.