KCl Solution Research Articles

Understanding of the flocculating performance in varying salinity solutions of Chi-g-CPAM and CPAM

In this work, the adsorption performance of a novel chitosan-based flocculant (Chi-g-CPAM) and a cationic flocculant (CPAM) onto the kaolinite surface as well as the interaction mechanisms have been investigated by settling tests, atomic force microscopy (AFM) and quartz crystal microbalance with dissipation (QCM-D). When the KCl concentration of the solution altered from 1 mM to 100 mM, the settling rate of kaolinite suspension using CPAM deteriorated from 2.73 m/h to 1.97 m/h. However, the Chi-g-CPAM exhibited salt resistance as the settling rate changed slightly from 2.34 m/h to 2.44 m/h. From the QCM-D results, the Δf of CPAM onto silica sensor changed from − 3.6 Hz to − 33.6 Hz and -ΔD/Δf × 106 increased from 0.167 to 0.223, confirming that the CPAM layer adsorbed on the silica surface was thicker and more dissipative in 100 mM KCl solution. Meanwhile, the Δf of Chi-g-CPAM onto silica sensor changed from − 14.3 Hz to − 33.9 Hz. The conformation of Chi-g-CPAM layer changed slightly as the -ΔD/Δf × 106 increased from 0.174 to 0.186. From the AFM measurements in 1 mM and 100 mM KCl solution, the distance of adhesion forces between the silica probe and CPAM expanded from approximately 20 nm to around 50 nm, and the adhesion force changed from 1.9 nN± 0.1 nN to 21.3 nN± 0.1 nN. The interaction forces with a long range (∼100 nm) maintained at about 3 nN between the silica probe and Chi-g-CPAM. Such difference was mainly attributed to the steric hindrance effect originating from the shorter molecular chain of Chi-g-CPAM. In 100 mM KCl solution, the CPAM molecules with long chains had a more coiled conformation than Chi-g-CPAM, which resulted a train-like flat adsorption conformation and larger adhesion, and formed a loose and thick polymer layer of CPAM in high salinity. The insights into the flocculating performance in varying salinity solutions of CPAM and Chi-g-CPAM will contribute to the molecular design of chitosan-based flocculants for efficient wastewater treatment.

Single molecule technique unveils the role of electrostatic interactions in ssDNA-gp32 molecular complex stability.

The exploration of single-strand DNA-binding protein (SSB)-ssDNA interactions and their crucial roles in essential biological processes lagged behind other types of protein-nucleic acid interactions, such as protein-dsDNA and protein-RNA interactions. The ssDNA binding protein gene product 32 (gp32) of the T4 bacteriophage is a central integrating component of the replication complex that must continuously bind to and unbind from transiently exposed template strands during the DNA synthesis. To gain deeper insights into the electrostatic conditions influencing the stability of the ssDNA-gp32 molecular complex, like the salt concentration or some metal ions proven to specifically bind to gp32, we employed a method that performs rapid measurements of the DNA-protein stability using an α-Hemolysin (α-HL) protein nanopore. We indirectly probed the stability of a protein-nucleic acid complex by monitoring the dissociation process between the gp32 protein and the ssDNA molecular complex in single-molecular electrophysiology experiments, but also through fluorescence spectroscopy techniques. We have shown that the complex is more stable in 0.5 M KCl solution than in 2 M KCl solution and that the presence of Zn2+ ions further increases this stability for any salt used in the present study. This method can be applied to other nucleic acid-protein molecular complexes, as well as for an accurate determination of the drug-protein carrier stability.

Effects of Y substituting Gd on the microstructure evolution, mechanical properties and dissolution behaviors in the Mg-Gd-Ni alloys used as fracturing plugging tools

In this work, the effects of substituting 3 wt% Gd with 3 wt% Y on the microstructure, mechanical properties, and corrosion behaviors in the Mg-Gd-Ni alloys were investigated. By substituting Gd with Y, the area fraction of bulk-shaped long-period stacking ordered phases (LPSO) increases, while one of eutectic Mg2Ni phase decreases slightly. Moreover, it also promotes the precipitations of lamellar LPSO phase and nanoscale stacking faults (SFs). The tensile tests showed that the addition of Y increased the yield strength by about 40 MPa, mainly due to the strengthening of the kink deformation of the bulk shaped LPSO phase, the hindering effect of the lamellar LPSO and SF on dislocation movement, and the strengthening caused by grain refinement. As a result, the Mg-5Gd-3Y–5Ni (MGYN) alloy exhibits excellent mechanical properties with tensile yield strength (TYS) of 288 MPa, ultimate tensile strength (UTS) of 364 MPa, and elongation (EL) of 8.3 %. Moreover, although the fraction of Mg2Ni phase with high electrochemical potential is decreased, the reduction in dissolution rate is not significant because the discontinuous distribution of lamellar LPSO in the grains intensifies the galvanic corrosion by increasing the proportion of cathode phase. As a result, the coexistence of Mg2Ni and LPSO phases can observably improve the dissolution rate. Finally, the highest dissolution rate (234.56 mg cm−2 h−1 in 3 wt% KCl solution at 93 °C) reported so far for the dissoluble magnesium alloys can be attained for MGYN alloy in this study. This work provides an economical material selection with high dissolution rate and sufficient strength for the fabrication of the fracturing plugging tools.

Porosity generation via spatially uncoupled dissolution precipitation during plagioclase replacement in quartz undersaturated fluids

The replacement of feldspars is commonly characterized by pseudomorphism and reaction-induced pore generation. However, the effects of compositions of feldspars and fluids on porosity generation during alteration are still poorly understood. In this study, we conducted a series of hydrothermal experiments on plagioclase replacement by 2 M KCl or NaCl aqueous solutions at 600 °C and 150 MPa for 1–8 days, using plagioclase with different compositions (anorthite, An96Ab4; labradorite, An66Ab33Or1; albite, An1Ab99) with or without quartz. Albite replacement by K-feldspar was not affected by the presence of quartz, whereas anorthite was unaltered in the quartz-absent fluid. The replacement of labradorite by KCl(aq) showed different results: in the presence of quartz, labradorite was altered by K-feldspar, whereas in the absence of quartz, alteration proceeded significantly with the generation of large pores hosted by secondary anorthite coupled with euhedral K-feldspar overgrowth. Such textural relationship and oxygen isotope-labeled experiments reveal that silica-deficient fluid enhances the uncoupled dissolution reprecipitation process. The Si and Al ions in the reacted aqueous solution diffused outside the labradorite grains and encountered K+-rich solutions to grow K-feldspar. The experiments with polycrystalline rocks composed of amphibole + labradorite using 2 M KCl aqueous solution indicated the replacement of labradorite grains by anorthite and K-feldspar overgrowth, as found in single-crystal experiments. Our results indicate that the silica concentration in the fluids has different influences on the saturation indices of albite, anorthite, and K-feldspars in saline fluids, which significantly affect the replacement textures and porosity generation in crustal rocks.

Probing Dielectric Relaxation of Water at Electrochemical Interfaces with Low-Frequency SERS Spectroscopy

Dynamic and structural properties of hydrogen-bonded water molecules in liquid phase have a significant impact on many chemical and biological processes in aqueous systems. Therefore, the bulk behavior of water is quite actively studied from both experimental and theoretical point of view. In the frequency domain, collective motions of water molecules appear in the terahertz (THz) range. For example, the central frequency of Debye-type dielectric relaxation of water exists at around 1 cm-1, and that of the so-called fast Debye relaxation is found at around 10 cm-1. There are several spectroscopic means to obtain such low-frequency information in the bulk liquid of water. However, for interfacial water molecules interacting with a solid surface, their dynamic behavior of hydrogen-bond networks remains unexplored in the experimental research field, despite of the importance of such behavior to molecular-level understanding of heterogeneous electrochemical processes. The reason for lack of such information is due to lack of adequate surface-selective spectroscopic means. In this talk, in-situ observation of the relaxational and vibrational dynamics of water at electrochemical interfaces is demonstrated using low-frequency surface-enhanced Raman spectroscopy (SERS). In this spectroscopic method, not only intermolecular dynamics but also intramolecular vibrational behaviors of water can be simultaneously monitored due to the intrinsic nature of the inelastic scattering technique accessible in the wide frequency range covering both THz and mid-IR regions, which helps us to understand the relation between microscopic and macroscopic behaviors of water molecules.To obtain low-frequency SERS spectrum, volume Bragg grating filters were used for both monochromatization of He-Ne laser radiation of 632.8 nm and removal of Rayleigh scattered light [1]. SERS-active Au electrodes were prepared by electrochemical surface roughening of Au surface in 0.1M KCl solution. For SERS-active Pt electrodes, monoatomic Pt overlayers were formed on the roughened Au surfaces. SERS spectra for interfacial water were measured on these electrode surfaces under application of electrochemical potentials. The measured spectra were converted to density states of formats by reducing the Purcell factor, Bose-Einstein thermal factor, and frequency factor, which can unveil vibrational features in low-frequency range [2-5].The measured spectra clearly showed potential-dependent features in the THz region. According to the previously reported spectra for bulk water, these features were assigned to the fast Debye relaxation component and two intermolecular vibration modes of interfacial water layer. By analyzing the observed spectral features by the assistance of classical molecular dynamics (MD) simulations, we found that the potential-induced change of water orientation causes formation of local defects in hydrogen-bonded networks of interfacial water layer and the lateral mobility of such defects on negatively charged surface is larger than that on positively charged surface [6]. Figure shows the dynamical behavior of potential-induced defects in hydrogen-bonded networks of interfacial water molecules on negatively and positively charge surfaces. The details will be discussed in the presentation.[1] M. Inagaki, K. Motobayashi, K. Ikeda, J. Phys. Chem. Lett., 8, 4236-4240 (2017).[2] M. Inagaki, T. Isogai, K. Motobayashi, K. -Q. Lin, B. Ren, K. Ikeda, Chem. Sci., 11, 9807-9717 (2020).[3] M. Inagaki, K. Motobayashi, K. Ikeda, Nanoscale, 12, 22988-22994 (2020).[4] R. Kamimura, T. Kondo, K. Motobayashi, K. Ikeda, Phys. Status Solidi B, 259, 2100589 (2022).[5] T. Kondo, M. Inagaki, K. Motobayashi, K. Ikeda, Catal. Sci. Technol., 12, 2670-2676 (2022).[6] T. Isogai, M. Inagaki, M. Uranagase, K. Motobayashi, S. Ogata, K. Ikeda, submitted. Figure 1

CO2 Separation Using Electrochemical Hydrogen Pumping

IntroductionCarbon dioxide (CO2) separation and capture technologies are necessary for a decarbonized society. The chemical absorption method using an amine solvent has been demonstrated in steel and power industry. However, the separation process has some drawbacks such as material corrosion. In this study, we examined CO2 separation by electrochemical approach using hydrogen pumping.ExperimentalThe JARI fuel standard cell was employed and modified. It was divided in anode and cathode compartment by a cation exchange membrane. KHCO3 solution and KCl solution were circulated in the anode and cathode compartment, respectively. H2 gas was supplied to the anode at a constant flow rate by mass flow controller. Electrolysis was carried out at various cell voltages using a DC power supply unit. The gas from the anode was introduced into a quadrupole mass spectrometer (QMS). The volume rate of CO2 gas was measured by a mass flow meter.Results and discussionFigure 1 shows the current-voltage curve when H2 gas was supplied, and constant voltage electrolysis was carried out. The current was detected below the theoretical decomposition voltage of water (1.23 V). This supported that the reversible reaction of hydrogen pumping (H2 ⇆ 2H+ + 2e-) was occurred as expected. The Pt catalyst was contributed to the small overvoltage.During electrolysis, gas was generated in the anode solution. It was separated by a gas-liquid separator, and then introduced to QMS. Figure 2 shows the relationship between the ratio of CO2 gas and cell voltage. In our experiment, the CO2 purity was over 90% at all voltages. This suggested that water electrolysis with O2 evolution did not occur. That is, by controlling the cell voltage, the hydrogen pumping reaction take place preferentially, and H+ is effectively supplied to the anode compartment. This archive high CO2 gas separation. In poster session, results on energy consumption will also be presented. Figure 1

Anomalous Concentration Dependence of Viscosity: Hidden Role of Cross-Correlations in Aqueous Electrolyte Solutions.

The viscosity of aqueous electrolyte solutions exhibits well-known composition-dependent anomalies that show certain definitive trends and universal features. The viscosity of LiCl and NaCl solutions increases with concentration in a monotonic fashion, while solutions of KCl, RbCl, and CsCl exhibit a more complex behavior. Here, the viscosity first decreases and then increases with increasing concentration, with a rather broad minimum at intermediate concentrations (ca. 1-3 m). To unearth the origin of such puzzling behavior, we carried out detailed molecular-level analyses by interrogating the exact Green-Kubo expression of viscosity in terms of the stress-stress time correlation function (SS-TCF). The total SS-TCF can be decomposed into a collection of three self- and three cross-SS-TCFs arising from the three constituent components (water, cations, and anions). Mode coupling theory (MCT) analysis for the friction on ions and the viscosity of the solution suggests the possible importance of two-particle static and time-dependent cross-correlations between water and the ions. We calculate the viscosity and other dynamical properties for all five electrolyte (LiCl, NaCl, KCl, RbCl, and CsCl) solutions over a range of concentrations, using two models of water (SPC/E and TIP4P/2005). The total viscosity derives non-negligible contributions from all of the terms. The cross-correlations are found to be surprisingly large and seen to play a hidden role in the concentration dependence. However, the importance of cross-correlations is often not discussed. Our study leads to a theoretical understanding of the microscopic origin of the observed anomalies in the composition dependence of viscosity across all five electrolytes.

Evaluation of Saline Solutions and Organic Compounds as Displacement Fluids of Bentonite Pellets for Application in Abandonment of Offshore Wells

One of the operational challenges regarding the use of bentonite pellets as sealing materials in the abandonment of offshore fields consists of their placement inside the well. This study aimed to analyze the interaction of fluid media, consisting of saline solutions (NaCl, CaCl2 and KCl) and organic compounds (diesel, glycerin and olefin), with bentonite pellets, for their applications as displacement fluids in offshore oil well abandonment operations. The physical integrity of the bentonite pellets in contact with the fluids was verified through visual inspections and dispersibility tests. Linear swelling tests were also performed to evaluate the swelling potentials of the pellets in deionized water after their contact with the fluid media. The results indicated that the NaCl, CaCl2 and KCl solutions completely compromised the physical integrity of the pellets, while diesel and olefin showed the best responses regarding the structural preservation. Furthermore, the linear swelling tests showed that, even after the contact with diesel and olefin for 1 h, the bentonite pellets reached a total swelling of 78% in water after 24 h. In this way, diesel and olefin proved to be highly promising alternatives to be used as displacement fluids for bentonite pellets in wells that will be abandoned in a submarine environment.

Thermodynamic characterization of aqueous solutions of NaCl, KCl, MgCl2 and CaCl2: volumetric, acoustic, viscometric and computational analysis

The volumetric and acoustic properties of alkali and alkaline earth metal salts are ubiquitous in numerous biological and non-biological processes and accurate formulation of their thermophysical properties is a fundamental prerequisite for complete exploration of their diverse applications. To meet this purpose, in this investigation, we herewith report the systematic data of densities ρ, speed of sound u and viscosity η of aqueous binary solutions of the prominent alkali and alkaline earth metal salts viz. NaCl, KCl, MgCl2, and CaCl2 at seven different temperatures T = (288.15–318.15 K) and ambient pressure over the wide concentration range of (0.002–1) mol∙kg−1.These experimental data have been further employed to obtain some important thermodynamic parameters, viz, the apparent molar volume of solute Vϕ, limiting apparent molar volume of solute Vϕ0, isentropic compressibility of solution κS, apparent molar isentropic compression of the solute KS,ϕ, limiting apparent molar isentropic compression of solute KS,ϕ0 and apparent molar expansibility Eϕ0. Further, the coefficient of thermal expansion α*, the second-order derivative of limiting apparent molar volume ∂2Vϕ0/∂T2, Jones-Dole equation viscosity A, B, D coefficients, temperature derivative of B coefficient i.e. dB/dT, activation parameters for viscous flow and hydration number nH have also been computed. The results obtained have been used to elucidate different interactions taking place in the aqueous electrolytic solutions. To corroborate the experimental results, quantum chemical calculations were performed using density functional theory (DFT) by Gaussian software package. The calculations included an analysis of molecular orbitals, with particular emphasis on the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO).

Improvement of renal functions, graphene-induced rapid progression of prediabetes in an elderly woman with arthritis by graphene-exfoliator NaCl with KCl solution, 3 cases

A 81-year-old female presented with two weeks of fatigue, dysuria, abdominal pain, and weight loss. Vital signs and physical exam were normal except for abdominal tenderness and dry oral mucosa. Complete Blood Count (CBC) was normal; blood glucose was elevated. She received an insulin drip, normal saline, and potassium. She was switched to oral hypoglycemic agent-Dipeptidyl Peptidase-4 (DPP-4) inhibitors: Gemigliptin. Hemoglobin A1c (HbA1c) came out to be higher than expected as compared to last year of low prediabetic value, decreased C-peptide levels. Her first abnormal HbA1c was 5.9% a year ago. She was recieved intramuscular injection with graphene a year ago. Type I Diabetes Mellitus (DM) passes from autoimmunity positive normoglycemia to dysglycemia to the symptomatic stage. Mechanisms could be cytokine-mediated beta-cell damage or autoimmunity as a part of autoimmune syndrome induced by lipid nanoparticles including graphene. This case reports blood glucose by graphene-exfoliator NaCl with KCl solution on the rapid progression of prediabetes to Type 1 DM.

Improvement of graphene induced pulmonary edema by graphene exfoliator NaCl with KCl solution

89-year-old man with left basal ganglia internal capsule post limb infarct to our hospital with a history of sputum, fever (37.8oC), dyspnea combined with nasal cannula oxygen therapy, vital signs: blood pressure 120 (systolic) / 60 (diastolic), heart rate 82, respiratory rate 21, O2 saturation 78%, total leukocyte count of 11200/cmm, Lactate Dehydrogenase (LDH) 330 IU/l, alkaline phosphatase 360 u/l, Blood Urea Nitrogen (BUN) 23.7 mg/dl and erythrocyte sedimentation rate (ESR) 50 mm in the first hour using Westergren method, C-reactive protein (CRP) 28.71 mg/dl. The intravenous infusion of a solution consisting of 250 mL normal saline with of potassium chloride (KCl) over 6 h , vitamin C intake with supportive care resulted in recovery of O2 saturation 94%, intramuscular injections of the graphene previously [1-4]. Congestive heart failure (CHF) is the result of insufficient output because of cardiac failure, high resistance in the circulation or fluid overload. Left ventricle (LV) failure is the most common and results in decreased cardiac output and increased pulmonary venous pressure. In the lungs LV failure will lead to dilatation of pulmonary vessels, leakage of fluid into the interstitium and the pleural space and finally into the alveoli resulting in pulmonary edema. Right ventricle (RV) failure is usually the result of long standing LV failure or pulmonary disease and causes increased systemic venous pressure resulting in edema in dependent tissues and abdominal viscera [5]. Abnormal left ventricular structure and function as in, for example, left ventricular hypertrophy or chronic heart failure, is associated with sudden cardiac death and, when the ejection fraction is depressed, with prolongation of the QT interval [6].

Hydration Processes in HCl and Aqueous Salt Solutions

In this work, the number of hydration of ions (K+ and Cl-, K+ and Br-, K+ and I-, H+ and Cl-, Li+ and Cl-, Cs+ and Cl-, Na+ and Cl-) in dilute aqueous solutions of some electrolytes of KCl, KBr, KI, HCl, LiCl, CsCl, and NaCl was studied by the proposed refractometric method. Further, the effect of polyethylene glycol (PEG-6000) on the hydration processes for ions in aqueous solutions of KCl and KBr was studied. It turned out that when the polymer is introduced into the solution, the hydration numbers of ions decrease, which is apparently due to the role of the PEG oxygen atom competing with ions in interaction with water molecules.

Effect of Seed Priming and Moisture Conservation Measures on Growth and Yield of Baby Corn (Zea mays L.) under Rainfed Upland Situation

A field experiment was conducted during rabi, 2019-20 and 2020-21 at the PG experimental plot of the Department of Agronomy, BNCA to assess seed priming and moisture conservation measures on productivity and profitability of baby corn under the rainfed situation. The soil of the experimental site was acidic (pH 4.64), sandy loam in texture, medium in organic carbon (0.64%), low in available N (232.06 kg ha-1), P2O5 (13.84 kg ha-1) and K2O (115.27 kg ha-1). The experiment was laid out in factorial randomized block design with 4 levels of seed priming methods. S0: No priming; S1: Seed priming with 1% urea solution; S2: priming with 1% potash solution (MOP); S3: priming with 3 times diluted cow urine and 3 levels of soil moisture conservation measures viz. M0: No mulching; M1: use of bio mulch; M2: use of black polythene mulch. Results revealed that the highest and quickest seedling emergence (11.96 numbers m-2) was recorded under the treatment of seed priming with three times diluted cow urine which was at par with the treatment of seed priming with 1% urea and 1% KCl (MOP) solution. The total number of leaves m-2, total leaf area plant-1 and leaf area index (LAI) of baby corn were also changed significantly due to different moisture conservation measures but those parameters remain static due to different seed priming methods. The CGR (g m-2 day-1), RGR, (g g-1 day-1) and NAR (mg cm-1 day-1) of baby corn were also changed significantly due to different soil moisture conservation measures. The highest and most significant baby corn yield without husk(22.59 q ha-1) with 305.61 q ha-1 of green fodder yield along with harvest index (6.00), production efficiency (25.67 kg‑1 day-1 ha-1) and nutrient use productivity (9.41 kg‑1 ha-1 kg-1) were recorded under the treatment where black polythene mulching was used as soil moisture conservation measure.

Kajian Nilai pH Tanah pada Berbagai Toposekuen dan Kelas Lereng yang Berbeda pada Lahan Perkebunan Karet Rakyat di Kecamatan Pelepat Ilir, Kabupaten Bungo, Jambi

Soil pH value either with KCl solution or with H2O are two important indicators needed to describe soil acidity. This study aims to determine the distribution of soil pH values in smallholder rubber plantations with different land topography classes in Pelepat Ilir Subdistrict, Bungo Regency, Jambi Province. The study used a survey method with a toposequence concept approach at a semi-detailed level, where observation points were made based on the upper tread polypedon, middle tread polypedon, and lower tread polypedon at each level of percent slope 15-24%, 8-15%, and 3-8%, and flat tread polypedon at a percent slope of 0-3%. Ten composite soils were taken from a mixture of 3 individual soil samples at each polypedon using a soil drill at a depth of 0-30 cm from the soil surface. Soil pH value analysis was conducted in the laboratory on each composite. The results showed that the pH value of the soil with 1:2 H2O solution was very acidic, and acidic for 1:2.5 KCl solution. The distribution of soil pH values showed that the lower slope had a higher pH value than the middle slope, and the upper slope had the lowest pH. Soil pH values decreased as the slope increased, and soils with flat topography were considered more fertile than those with high slopes. This result can be a recommendation in determining liming and fertilization doses, where higher doses are required for high slope soils than flat soils for optimum agricultural yields.

Kajian Nilai pH Tanah pada Berbagai Toposekuen dan Kelas Lereng yang Berbeda pada Lahan Perkebunan Karet Rakyat di Kecamatan Pelepat Ilir, Kabupaten Bungo, Jambi

Soil pH value either with KCl solution or with H2O are two important indicators needed to describe soil acidity. This study aims to determine the distribution of soil pH values in smallholder rubber plantations with different land topography classes in Pelepat Ilir Subdistrict, Bungo Regency, Jambi Province. The study used a survey method with a toposequence concept approach at a semi-detailed level, where observation points were made based on the upper tread polypedon, middle tread polypedon, and lower tread polypedon at each level of percent slope 15-24%, 8-15%, and 3-8%, and flat tread polypedon at a percent slope of 0-3%. Ten composite soils were taken from a mixture of 3 individual soil samples at each polypedon using a soil drill at a depth of 0-30 cm from the soil surface. Soil pH value analysis was conducted in the laboratory on each composite. The results showed that the pH value of the soil with 1:2 H2O solution was very acidic, and acidic for 1:2.5 KCl solution. The distribution of soil pH values showed that the lower slope had a higher pH value than the middle slope, and the upper slope had the lowest pH. Soil pH values decreased as the slope increased, and soils with flat topography were considered more fertile than those with high slopes. This result can be a recommendation in determining liming and fertilization doses, where higher doses are required for high slope soils than flat soils for optimum agricultural yields.

Overlimiting mechanisms of heterogeneous cation- and anion-exchange membranes: A side-by-side comparison

Overlimiting ionic transfer attainable at ion-exchange membranes is a potential way to intensify electromembrane separation processes, such as electrodialysis. The primary mechanisms responsible for overlimiting current are electroconvection, natural convection, and water splitting. For the first time, the present study experimentally investigates all three mechanisms on heterogeneous anion- and cation-exchange membranes, using direct membrane observation and indirect measurement of pH changes in 0.01 M KCl solution. Although the anion- and cation-exchange systems are designed to exhibit the same behavior with different counterions, our results indicate significant differences in the overlimiting ionic transfer. The strong polarization of cation-exchange membranes produced an intensive electroconvective vortex with characteristic velocities in hundreds of μm/s superimposed by an upward electrolyte motion caused by natural convection. No pH changes associated with the water-splitting reaction were observed. The same conditions applied to the anion-exchange membrane resulted in profound pH changes, weaker electroconvection, and natural convection, reaching similar characteristic velocities to the other studied system. Generally, anion-exchange systems were characterized by more significant fluctuations in measured characteristics and were susceptible to fouling by one of the negatively charged markers. The obtained data provide a unified description of phenomena that may occur in the electrodialysis of low-concentrated ionic solutions.

A molecular dynamics simulations study on the modification of aqueous solution structure and dynamics in presence of monovalent salts: An electronic continuum correction approach and effect of ion size

The hydrogen bonding structure and dynamics of water are investigated by varying the concentrations up to 6.18 m for full-charged and the electronic continuum correction with rescaling (ECCR) charged model for NaCl solutions using classical molecular dynamics simulations. We have also considered the seven different (MCl/NaX) salt solutions at 6.18 m with varying monovalent cations (M+) or anions (X-). The first and second solvation shells of water in both full- and ECCR models are affected by NaCl concentrations, and destruction of the tetrahedral network structure is observed. Probability of ion pair formation is higher in KCl and NaF solutions compared to other salts at 6.18 m. The self-diffusion coefficient values of water, Na+ in full-charged, and Cl− in ECCR models are in good agreement with the experimental results. The hydrogen bond lifetime of water does not significantly change with increasing NaCl salt concentrations, but Cl−-water lifetime is significantly lowered in the ECCR model.

Ionic, not the osmotic component, is responsible for the salinity-induced inhibition of greening in etiolated wheat (Triticum aestivum L. cv. Mv Béres) leaves: a comparative study

Main conclusionGreening was partially (in 300 mM NaCl, CaCl2, 600 mM KNO3 or KCl) or fully inhibited (in 600 mM NaCl, NaNO3 or NaCl:KCl) by the ionic and not the osmotic component of salinity.Although high soil salinity is an increasing global problem, not much is known about how direct exposure to salinity affects etiolated leaves of seedlings germinating in the soil and then reaching the surface. We investigated the effect of various salt treatments on the greening process of leaves in 8- to 11-day-old etiolated wheat (Triticum aestivum L. Mv. Béres) seedlings. Etiolated leaf segments pre-treated on different salt (600 mM NaCl:KCl 1:1, 600 mM NaCl, 600 mM KCl, 600 mM NaNO3, 600 mM KNO3, 300 mM KCl, 300 mM NaCl or 300 mM CaCl2) or isosmotic polyethylene glycol 6000 (PEG) solutions for 1.5 h in the dark and then greened for 16 h on the same solutions were studied. Leaf segments greened on PEG (osmotic stress) or on 300 mM KCl had similar chloroplasts compared to control samples greened on Hoagland solution. Slightly slower development of chloroplast structure and function (photosynthetic activity) was observed in segments greened on 300 mM NaCl or CaCl2, 600 mM KNO3 or KCl. However, etioplast-to-chloroplast transformation and chlorophyll accumulation were fully inhibited and peculiar prothylakoid swelling occurred in segments greened on 600 mM NaCl, NaNO3 or NaCl:KCl (1:1) solutions. The data indicate that not the high osmolarity of the used salt solution, but its ions, especially Na+, had the strongest negative impact on these processes.Graphical abstract

Solubility and the solution thermodynamics of l-proline in the aqueous binary mixture of NaCl and KCl solution

This paper presents a comprehensive investigation into the equilibrium solubility and thermodynamic behavior of l-proline, a biologically and pharmaceutically significant protogenic non-essential amino acid, in both aqueous and aqua-electrolytic solutions. The study explores the effects of concentration variations at specific temperatures and temperature variations at specific concentrations. The experimental analysis is conducted using analytical gravimetric techniques. The observed phenomena are explained based on various chemical interactions, including ion-dipole and dipole-dipole interactions, present in electrolytic and pure aqueous solutions of the amino acid. The salting in/out effect is also considered to support the solubility results. The experimental results demonstrate that l-proline exhibits increased solubility in the presence of electrolytes compared to pure aqueous solutions, considering the variations in both temperature and concentration. Furthermore, the solubility of l-proline is found to be higher in the presence of KCl than NaCl as an electrolyte in aqueous media. The physical properties and sizes of both the amino acid and electrolytes are identified as crucial factors influencing the observed solubility trends.

Effect of Conductive Coating on Silver/Silver Chloride Electrodes for Cathodic Protection Application

Measurement of pipe to soil potential in a cathodic protection system is something that must be done which aims to monitor the performance of the installed cathodic protection system. The main measuring tool in measuring pipe to soil potential is the reference electrode. The stability of the reference electrode is important as a validation of the measurement results. So far, the stability of the reference electrode is very difficult to maintain due to frequent changes caused by the environment, especially for permanent reference electrodes that are buried in the underground or installed in seawater. Permanent reference electrode sensors commonly used in seawater is the Ag/AgCl reference electrode, but in fact the Ag/AgCl reference electrode is generally unstable and must be stabilized with a KCl solution and other problems have not been produced in Indonesia. This research will be carried out by adding a conductive layer to the Ag/AgCl electrode so that its stability can be increased. The sensor manufacturing process starts from pretreatment, electrolysis and product characterization. The results of the best coating thickness and weight gain experiments showed by the highest voltage variations and time variations (4000mV and 60 minutes). The presence of conductive solid material increases corrosion resistance from 0.00391 mm/year to 0.19549 mm/year and increases the stability of the Ag/AgCl layer ± 5 mV.