Concentrated NaCl Solutions Research Articles

Microstructure characteristics and cavitation erosion resistance of Co-based coating fabricated via laser cladding

Marine centrifugal pumps are important mechanical equipment widely used in ships, but they are often damaged due to cavitation. In this paper, a Co-based coating was prepared on the surface of a substrate via laser cladding technology. The microstructure characteristics and phase composition of the coating were analyzed by an optical microscope (OM), a scanning electron microscope (SEM), and an x-ray diffractometer. Ultrasonic vibration cavitation tests were used to test the cavitation erosion resistance of the coating in NaCl solutions with different concentrations (0, 2.5, and 3.5 wt. %).The experimental results showed that the coating is mainly composed of γ-Co, (Co,W)6C, and Cr23C6. After 12 h of cavitation testing in different concentrations of NaCl solution, the Co-based coating exhibited better anti-cavitation performance than the 316 stainless steel substrate. The corrosion rate of the Co-based coating was significantly lower than that of the 316 stainless steel substrate. In addition, the experimental results also showed that the higher the concentration of NaCl, the faster the weight loss rate of the Co-based coating and the more pronounced the degree of surface cavitation. Although a dense oxide protective layer is easily formed on the surface of the Co-based coating and effectively inhibits the further erosion of the corrosive medium, with the increase in the concentration of NaCl solution, the erosion by chloride ions is more likely to destroy the dense protective layer and formed cavitation holes.

Sodium doping and control during the preparation of α-hemihydrate gypsum in NaCl solution

Sodium doping and control during the preparation of α-hemihydrate gypsum in NaCl solution

Effect of drinking water salinity on lactating cows’ water and feed intake, milk yield, and rumen physiology

Use of desalinated seawater in arid and semiarid regions for domestic, industrial, and agricultural purposes is on the rise. Consequently, in those regions, drinking water offered to lactating cows has lower salinity and mineral concentrations than in the past. Although water with total dissolved solids (TDSs) of up to 1000ppm is considered safe for drinking, lower salinity level may affect rumen physiology, feed and water intake, or milk yield. Therefore, we evaluated the effect of drinking water salinity in an electrical conductivity (EC) range of 400 to 1000 micro Siemens (µS) / cm (TDS of 200 to 500ppm) on lactating cows' performance by artificially creating water EC > 400µS/cm by adding NaCl. Following 2weeks of adaptation to individual feeders and troughs, four Israeli Holstein multiparous lactating cows were offered, in a Latin square design, drinking water with EC levels of 400, 600, 800 or 1000µS/cm, through addition of concentrated NaCl solutions (measured EC in troughs averaged 418, 624, 811, and 1016µS/cm and 209, 312, 406, and 508 TDS ppm, respectively), for four periods of 18days each. Water EC in troughs was measured daily. Each period included 5days for washout, 10days for collecting data of feed and water intake, milk and milk component yields, and BW and 3days for samplings of milk, urine, faeces, and rumen fluid. Rumen pH and temperature were recorded continually by inserting loggers into the reticulorumen. We analysed the total tract apparent digestibility, rumen fluid volatile fatty acids and NH3, and mineral concentrations (Na, Cl, K, and N) in water, urine, faeces, and milk. Drinking water salinity was positively correlated with DM intake and energy-corrected milk yield, the latter showing the greatest response between EC of 400 and 600µS/cm. Digestibility of ash-free amylase-treated NDF was negatively correlated with water salinity. There was no significant effect of water EC on rumen volatile fatty acid or NH3 concentrations, or water intake. The results indicate possible effects of drinking water mineral concentrations on lactating cows' milk yield and rumen physiology, warranting further investigation.

Thermodynamic description of the Ni(II)-citrate system in alkaline, dilute to concentrated NaCl solutions. Formation of quaternary complexes with ca

Thermodynamic description of the Ni(II)-citrate system in alkaline, dilute to concentrated NaCl solutions. Formation of quaternary complexes with ca

High-Q Resonances Induced by Toroidal Dipole Bound States in the Continuum in Terahertz Metasurfaces

The radiation mode of the interaction between electromagnetic waves and materials has always been a research hotspot in nanophotonics, and bound states in the continuum (BICs) belong to one of the nonradiative modes. Owing to their high-quality factor characteristics, BICs are extensively employed in nonlinear harmonic generators and sensors. Here, the influence of structural parameters on radiation modes has been systematically analyzed using band theory; the mechanisms of quasi-BIC mode and BIC mode were also analyzed through multipole decomposition of scattered power and near-field distribution. Notably, this study presents the discovery that the toroidal dipole-BIC (TD-BIC) arises from the interference and cancellation of electric and toroidal dipoles. The research results indicate that the structure, which supports symmetry-protected BICs, is sensitive to variations in the concentration of NaCl solution in its surroundings, making it applicable for liquid detection in miniaturized metal sensors. The proposed scheme broadens the applicability of BIC-based sensors and provides a prospective platform for biological and chemical sensing.

Stress Corrosion Cracking of Brass in Chloride Solution

In this investigation, the resistance of brass material to stress corrosion cracking (SCC) in a chloride solution was assessed through adjustments in temperature (25°C, 35°C, and 45°C) and bending angles of the brass material (1.0 wt%, 2.0 wt%, and 3.5 wt%). The chosen solution closely resembles saltwater, making it suitable for testing, especially considering the widespread use of brass materials in various industrial sectors, particularly shipping. Stress corrosion cracking tends to impact brass materials under heavy loading. The primary objective of this study is to characterize the corrosion rate of brass materials. The method involved a bending test with angle variations of 180°, 90°, and 0°. Corrosion assessment utilized the Open Circuit Potential method, Anodic Polarization Tafel, and a digital microscope for the material's microstructure properties. According to the findings, brass material exhibits the lowest corrosion rate (10 x 10-6 mmpy) at a temperature of 25°C distilled water and an angle variation of 0°. Conversely, the corrosion rate increases with variations in bending angle, temperature, and the concentration of NaCl solution, as evidenced by the corrosion rate of 28.035 x 10-5 mmpy with an angle variation of 180°, to a corrosive solution of NaCl 3.5 wt% at a temperature of 45°C.

Selective Flotation of Galena and Sphalerite from a Pb/Zn Complex Sulfide Ore Using Saline Water: The Effects of Xanthate and Pine Oil Addition

ABSTRACT This study focuses on the effects of saline water on the selective flotation of a Pb/Zn complex sulfide ore. Batch flotation experiments were carried out using NaCl solutions as well as seawater. It was found that increasing NaCl concentration in solution from 1 mM to 500 mM had a positive effect on the Pb and Zn recoveries. When comparing recoveries in the highest NaCl concentration in solution to seawater, Pb recovery decreased by 48%, most likely due to the presence of additional ions such as Ca2+ and Mg2+. On the contrary, Zn recovery in seawater increased by 55%, and this increase could be attributed to the SO4 2- ion effect from seawater. DLVO-like theoretical analyses using pH-dependent charge regulated models of surface charge were employed to study particle-particle and particle-bubble interactions during sulfide ore flotation under different NaCl concentrations and solution pH. The theoretical predictions of the models supported the experimental results, with a stronger particle-bubble attraction predicted by the models at higher NaCl concentrations. Overall, results demonstrated the potential of using the theoretical predictions for describing the various interactions during sulfide ore flotation in saline water.

Heat Pump Evaporation: an Alternative of Membrane Filtration System Aiming Pure Water Production

Heat Pump Evaporation: an Alternative of Membrane Filtration System Aiming Pure Water Production

Real-Time 2D Mapping of Hydrogen Entry and pH Distribution inside a NaCl Droplet on an Fe Sheet Using a Hydrogenochromic Sensor

Atmospheric corrosion on a steel is known to promote hydrogen entry into the steel. However, the mechanism of corrosion-induced hydrogen entry is still unclear, because it is difficult to detect the small amount of hydrogen entered steels due to corrosion. In previous literature, electrochemical hydrogen permeation tests with Devanathan-Stachurski cells have been conducted to detect corrosion-induced hydrogen entry. While the electrochemical hydrogen permeation tests can measure the corrosion-induced hydrogen permeation current with high sensitivity and high time resolution, the hydrogen distribution in the steels cannot be measured. It has been challenging to analyze the two-dimensional information of corrosion-induced hydrogen entry. In this study, a hydrogenochromic sensor consisting of the polyaniline (PANI) and Ni layers was used to visualize the hydrogen distribution in an Fe sheet under corrosion conditions.A PANI layer polymerized on a metal surface reacts with atomic state hydrogen in the metal, resulting in the color change from blue or purple to yellow or transparent.1,2 The intermediate Ni layer between the metal surface and the PANI layer works as a catalysis of the hydrogenation reaction of the PANI layer.1 Therefore, the small amounts of hydrogen that entered the metals can be visualized using the hydrogenochromic sensor consisting of the Ni and PANI layers.3 –6 In this study, the Ni layer was plated on one side of an Fe sheet by current-static polarization at –30 A m–2 for 180 s in the Watts bath at 333 K. In addition, the PANI layer was electrically polymerized on the Ni layer at a constant voltage of 1 V for 200 s in a 0.5 M H2SO4-0.5 M aniline solution. A droplet of 0.1 M NaCl containing thymol blue was placed on the other side of the specimen (bare Fe surface). The color of thymol blue is known to be changed by the increase in pH from neutral to alkaline. Thus, the hydrogen entry behavior and pH change in the droplet were analyzed simultaneously by observing the droplet and hydrogenochromic sensor with digital cameras.Large crystallographic pits occurred in the initial stage of corrosion, but hydrogen entry was hardly promoted by the crystallographic pits. Subsequently, a rust-formed area was observed. Because the hydrogen entry proceeded under the rust-formed area, acidification was thought to occur under the rust-formed area, causing the hydrogen evolution reaction. The pH on the non-corroded area was alkaline, suggesting that alkalization proceeded on the non-corroded area due to the oxygen reduction reaction. The edges of the rust-formed area were close to the alkalized area, resulting in the thickening of rust at the edges. After the disappearance of the droplet due to drying, hydrogen entry almost ceased. However, hydrogen entry was confirmed under the thick rust layer formed at the edge of the rust-formed area. It was found that hydrogen entry is likely to proceed under the thick rust layer, which contains concentrated NaCl solution, even after the disappearance of the droplet.

Raman Quantitative Measurement on the Cl− Molarity of H2O-NaCl-CO2 System: Application to Fluid Inclusions

In this study, Raman spectroscopy is applied to determine the salinity of fluid inclusions in the H2O-NaCl-CO2 system. In the work, various systems are prepared, such as H2O-NaCl, H2O-CO2, and H2O-NaCl-CO2. For the H2O-NaCl system, the addition of NaCl salts decreases the intensity of the sub-band below 3330 cm−1 but increases the intensity of the sub-band above 3330 cm−1. According to the structural analysis of the H2O-NaCl system, the spectral changes are mainly related to the interactions between Cl− and water. After the Raman OH stretching bands are fitted into two sub-bands, the intensity ratio between them is used to calculate the Cl− concentrations (molarity scale) of NaCl solutions. Additionally, based on the measured Raman spectra, the effects of CO2 on water structure may be weak. It is reasonable to ignore the impact of dissolved CO2 on Raman OH stretching bands. The procedure above can be extended to quantitatively determine the Cl− molarity of the H2O-NaCl-CO2 system. To demonstrate its reliability, this method is applied to determine the salinity of synthetic and natural fluid inclusions containing CO2.

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.

Molecular Dynamics Simulation of Membrane Distillation for Different Salt Solutions in Nanopores.

Nanoporous membranes offer significant advantages in direct contact membrane distillation applications due to their high flux and strong resistance to wetting. This study employs molecular dynamics simulations to explore the performance of membrane distillation in a single nanopore, mainly focusing on wetting behavior, liquid entry pressure, and membrane flux variations across different concentrations and types of salt solutions. The findings indicate that increasing the NaCl concentration enhances the wetting of membrane pores, thereby decreasing the entry pressure of the solution. However, at the same salt concentration, the differences in wetting and liquid entry pressure among various salts, including CaCl2, KCl, NaCl, and LiCl, are minimal. The presence of hydrated ions significantly reduces membrane flux. As the concentration of NaCl solutions increases, the number of hydrated ions rises, thereby lowering the membrane flux of the salt solution. Furthermore, the type of salt has a pronounced effect on the structure of hydrated ions. Solutions with Ca2+ and Li+ exhibit the smallest first-layer radius of hydrated ions. Under the same salt concentration, KCl solutions demonstrate the highest membrane distillation flux, while CaCl2 solutions show the lowest flux.

Aminomethanesulfonic acid grafted polyamidoxime fibers with hydrophilicity, salt-tolerance and antimicrobial properties for highly efficient uranium extraction from seawater

Aminomethanesulfonic acid grafted polyamidoxime fibers with hydrophilicity, salt-tolerance and antimicrobial properties for highly efficient uranium extraction from seawater

In-situ growth of Ni, Co-Prussian blue nanocubes on molten salt etched lamellar Ti3C2Tx/Ni for enhanced hybrid capacitive deionization

In-situ growth of Ni, Co-Prussian blue nanocubes on molten salt etched lamellar Ti3C2Tx/Ni for enhanced hybrid capacitive deionization

Phase diagram of NaCl–water by computer simulations: performance of non-polarizable force-fields

This study evaluates the capabilities of two new ion force fields (Tanaka [Yagasaki et al. JCTC 2020] and Madrid-2019 [Zerón et al. JCP 2019]) in conjunction with the TIP4P/2005 model for water in reproducing the NaCl–water phase diagram using molecular dynamics direct coexistence simulations. The performance of those force-fields is critically compared with the phase diagram recently reported for the Joung Cheatham-TIP4P/2005 force-field [Bianco et al. JCP 2022]. Excellent agreement between the three force-fields and experiments is found for the ice-solution line due to the dominance of the water model in the location of this line. For the NaCl-solution line, the Tanaka and the Madrid-2019 models accurately predict solubility at ambient temperature, but they underestimate somewhat the experimental line as temperature increases. The JC model underestimates NaCl solubility both at ambient and at high temperatures. All models underestimate the stability of the NaCl·2H 2 O solid, which remains metastable with respect to NaCl. Equilibration of the NaCl·2H 2 O-solution system is challenging at low temperatures due to the slow diffusion of concentrated NaCl solutions. The phase diagrams obtained serve as a foundation for studying crystal nucleation, and solid-solution interfaces, and provide very valuable information for the development of imporved NaCl–H 2 O force-fields.

Effect of spacing, concentration of NaCl solution, and biasing of graphite electrodes towards conductometric sensor response

Effect of spacing, concentration of NaCl solution, and biasing of graphite electrodes towards conductometric sensor response

Effects of chemical solution components on the contact angle of typical minerals in soil: quartz, orthoclase and plagioclase

Different chemical solutions can significantly change the contact angle (CA) of soil, but few studies have studied the change rule and action mechanism of the CA from the mineral composition of soil essence. In unsaturated soil mechanics, the CA is an important parameter to calculate the wet suction between soil particles in unsaturated soil. When the chemical composition of the soil pore liquid changes, the CA will also change, which will affect the wet suction and other parameters, thus changing the macroscopic mechanical properties of the soil. In this study, the CA of air-solution-mineral phases with different solution components (pH, type and concentration of salt solution) of different minerals (quartz, orthoclase and plagioclase) were measured. The results show that the CAs of quartz, orthoclase and plagioclase all rise first and then drop with the rise of pH. The peak CAs are pH = 5, pH = 4 and pH = 3, respectively. Quartz, orthoclase and plagioclase all have valley values in different concentrations of NaCl and KCl solutions. In CaCl2 solution, only quartz has valley value, while orthoclase and plagioclase increase monotonously. Quartz in soil plays a main role in the influence of soil CA, followed by orthoclase and plagioclase. The CA of different minerals in different chemical solutions is mainly controlled by electric double layer interaction and functional groups interaction. In different salt solution environment, in addition to the above two effects, the mineral CA is also affected by the surface tension.

Synthesis of MnFe2O4 Spinel on Rusted Q235 Steel Surface and Its Corrosion Resistance Properties.

Corrosion of steel is an issue that cannot be ignored in contemporary society. Due to large-scale corrosion, it is urgent to develop a surface treatment process that enhances the corrosion resistance of steel, allowing for application in various scenarios as needed. This study aims to investigate a novel surface treatment process to extend the service life of corroded Q235 steel, reduce its sensitivity to corrosion, and enable its use in multiple environments. This study employs the sol-gel method, using manganese nitrate solutions of varying concentrations to treat the surface of Q235 steel after different electrolysis times. The optimal conditions for precursor preparation were found to be a Mn2+ concentration of 0.1 mol/L and an electrolysis time of 2 h. Electrochemical tests using NaCl solutions of different concentrations revealed a significant reduction in the corrosion current for the composite coating based on Q235 steel treated with this method in NaCl solutions with wt.% = 1, 2, 3, 4, 5. Furthermore, the resistance to corrosion was strongest in the NaCl solution with a concentration of 1 wt.% where the corrosion current decreased from 24.8 µA/cm2 to 6.79 µA/cm2. Additionally, the coating was found to be diffusion-controlled in the early stages of the corrosion process and charge transfer-controlled in the later stages. The MnFe2O4 spinel coating demonstrated the greatest enhancement in corrosion resistance in the wt.% = 1 NaCl solution.

Galvanic Corrosion Behavior of Zn and Al Couples in NaCl Solution

Multi-materialization is being promoted in automotive structural materials, and fuel economy is being improved by replacing steel with aluminum and other lightweight metallic materials. Automotive steel is often galvanized for corrosion protection, and galvanic corrosion of aluminum and zinc in an atmospheric environment is a very important issue in evaluating automotive durability. Zinc is usually considered to be an anode when combined with aluminum, but its galvanic corrosion behavior can be complicated by environmental conditions because the corrosion potentials of the two are relatively close. Therefore, the objective of this study is to investigate the galvanic corrosion behavior of the couples consisting of zinc and aluminum under corrosive environmental conditions.The galvanic couple used in this study was fabricated from AA1050 Al and zinc plates. The width and length of both plates are 10 mm and 15 mm, respectively. After connecting lead wires to each plate, both plates were embedded in epoxy resin. To fabricate coplanar galvanic couples in this study, both plates were placed separately along the surface from a gap size of 500 um. The surfaces of the galvanic pairs were polished with SiC paper to JIS 2000 grit and cleaned with EtOH. The test solutions used in this study were aqueous NaCl solutions of various concentrations from 0.01 to 2 M, prepared with Milli-Q water and reagent grade chemicals. Galvanic currents and corrosion potentials were measured to investigate the galvanic corrosion behavior of the couples after 72 hours of galvanic corrosion experiments in the test solutions.The results of the galvanic corrosion test showed that the immersion potentials of the galvanic couples were lower at higher NaCl concentrations. The galvanic current decreased with immersion time, finally reaching about 1 uA in all NaCl solutions. The results of the electrochemical impedance measurements for galvanic couples in various NaCl concentrations showed that the impedance gradually increased with immersion time. It was also found that the impedance can be expressed as an electrical equivalent circuit consisting of two time constants, and that the impedance increases at intermediate frequencies between 0.1 and 1 Hz, which is thought to correspond to the dissolution reaction of Zn. This was the same trend as the behavior of the galvanic current. These results suggest that prolonged immersion reduces the galvanic current and the dissolution rate of zinc due to the passivation of the A1050 surface and the suppression of cathodic reactions.

CO2 solubility in aqueous solution of salts: Experimental study and thermodynamic modelling

AbstractThere are many economic obstacles and complex engineering problems associated with CO2 capture and storage in saline aquifers that need to be addressed. Overcoming such challenges requires precise knowledge on the fluid phase equilibria of CO2‐brine systems. Having accurate CO2 solubility data over a wide range of temperature and pressure can greatly assist in resolving these obstacles by improving the performance and accuracy of the thermodynamic modeling and subsequent CCS engineering success.CO2 solubility in pure water and NaCl solutions has been widely studied in the literature, however, there is a lack of data on CO2 solubility at lower temperatures (below 298 K). Furthermore, limited phase equilibria data are available for CO2 solubility in CaCl2, MgCl2, and KCl solutions at elevated temperatures (i.e., T > 323.15 K).In this work, the phase equilibria of CO2 and brine systems are investigated experimentally and theoretically. In this study, solubilities of CO2 in pure water and various concentrations of NaCl (10, 15, 20, and 22 wt%), KCl (10, 15, and 22 wt%), CaCl2 (7.5, 10, 15.7, and 23.4 wt%), and MgCl2 (6.7, 11, 18, and 29 wt%) aqueous solutions are reported. All CO2 solubilities were measures at 323.15, 373.15, and 423.15 K and over various pressure ranges, while solubilities in 10 and 20 wt% NaCl aqueous solutions were also measured over the temperature range of 263 to 298 K and pressures up to the hydrate dissociation pressure of each system. Equation of state modelling using the PC‐SAFT and the Cubic Plus Association equations of state, is performed in the theoretical part of the study to validate the measured solubility data. © 2024 The Author(s). Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.