Aqueous Potassium Chloride Research Articles

Determination of Protein Charge in Aqueous Solution Using Electrophoretic Light Scattering: A Critical Investigation of the Theoretical Fundamentals and Experimental Methodologies.

Studies are reported of the measurement of electrophoretic mobilities of bovine serum albumin (BSA) in aqueous potassium chloride solutions as a function of ionic strength and pH using electrophoretic light scattering (ELS). It is demonstrated that the use of palladium or platinum electrodes should be avoided and that platinized platinum electrodes are necessary to avoid interference from unwanted electrochemical phenomena at the electrode-liquid interface. Potentiometric acid titration was performed to quantify the amount of protonic charge per protein molecule at the same pH values as the electrophoretic mobility measurements. It is shown that appropriate selection of an electrokinetic model yields excellent agreement between predicted and experimental electrophoretic mobilities across the ranges of pH and ionic strength studied in accordance with the protonic charge values obtained by titration. The experimental results are explained in terms of protonation, chloride counterion binding, and protein molecule permeability. This work highlights specific requirements of using ELS for confident analysis of proteins in aqueous solutions.

Thermodynamically Traceable Calorimetric Results for Dilute Aqueous Potassium Chloride Solutions at Temperatures from 273.15 to 373.15 K. Part 2. The Quantities Associated with the Partial Molar Heat Capacity

In previous articles (Partanen J. Chem. Eng. Data 2019, 64, 16−33 and Partanen J. Chem. Eng. Data 2019, 64, 2519–2535), we presented traceable and transparent two-parameter Hückel equations (with parameters B and b1) for the activity coefficients of the salt and for the osmotic coefficients of water in aqueous KCl solutions in the temperature range of 273.15–383.15 K. The latter article is the first part (Part 1) of the calorimetric study. We showed in these articles that our equations for these solutions explain within experimental error the literature data on almost all thermodynamic quantities including the partial molar enthalpies at least up to a molality of 0.2 mol·kg–1 and up to 373 K. In this model, parameter B is regarded as a constant but parameter b1 has a quadratic temperature dependence. No calorimetric data were needed in the parameter estimation. In the second part (Part 2) of the calorimetric study, now, the results obtained for the heat capacity quantities of KCl (aq.) are considered. We show here that all heat capacity literature available for KCl solutions at least up to 0.5 mol·kg–1 is possible to explain within experimental error using exactly the same Hückel equations as those considered previously in our studies for dilute KCl solutions from 273 to 373 K. Because of the success of the used model, we supplement the existing thermodynamic tables with new values for the relative apparent and partial molar heat capacities for KCl solutions. It is likely that the new tables contain the most reliable values available for these heat capacity quantities.

Optimization of Pyrrole Electropolymerization on a Steel Gauze Electrode Using the Cyclic Voltammetry Method

Study on pyrrole electropolymerization is the preliminary step in synthesizing polypyrrole membranes, which can be used for various purposes in biosensor. In this work, electropolymerization process and electrochemical analysis of polypyrrole as an electroactive polymer have been studied by cyclic voltammetry. Pyrrole was electropolymerized to form polypyrrole in an aqueous potassium chloride solution at different pHs using phosphate buffer. The results showed that a potential range of 0-1200 mV is suitable for polypyrrole electropolymerization using the Ag|AgCl electrode as the reference. The formation of polypyrrole is stable at a scan rate of 100 mV/s. In addition, the optimized pyrrole electropolymerization was obtained using 0.1 M pyrrole and phosphate buffer at pH of 2-6. Taken together, this study can be used as a reference for the synthesis of other conducting polymers.

Thermodynamically Traceable Calorimetric Results for Dilute Aqueous Potassium Chloride Solutions at Temperatures from (273.15 to 373.15) K. Part 1. The Quantities Associated with the Partial Molar Enthalpy

In our previous study (Partanen, J. I.; Partanen, L. J.; Vahteristo, K. P., J. Chem. Eng. Data 2019, 64, 16–33), we presented a fully traceable two-parameter Huckel equation with parameters B and b1 for activity and osmotic coefficients in dilute KCl(aq) in the temperature range of (273.15 to 383.15) K. This equation applies within experimental error to almost all thermodynamic data in the literature at least up to a molality of 0.2 mol·kg–1. In our Huckel model, parameter B is treated as a constant, whereas parameter b1 depends quadratically on the temperature. In the present study, the same model is applied to the molar enthalpies of the components in KCl solutions. No new parameter estimations are necessary for the treatment of these calorimetric data. We also extend now the previous enthalpy results for dilute NaCl solutions (see Partanen, J. I.; Partanen, L. J.; Vahteristo, K. P., J. Chem. Eng. Data 2017, 62, 2717–2632) up to 373 K because in that study the treatment of calorimetric data was limited ...

Performance evaluation of aqueous organic redox flow battery using anthraquinone-2,7-disulfonic acid disodium salt and potassium iodide redox couple

An aqueous organic redox flow battery (AORFB) using anthraquinone-2,7-disulfonic acid disodium salt (2,7-AQDS) and potassium iodide (KI) as the negative and positive active species is suggested. The active species are dissolved into an aqueous potassium chloride (KCl) solution, while ethylene glycol (EG) and polyvinylpyrrolidone (PVP) are added to improve the solubility of 2,7-AQDS and prevent the side reactions of KI. The aqueous solubility of redox couple improved by the utilization of additive plays a role in increasing both capacity and the performance of AORFB, while as kinetic parameters to affect the capacity, electron transfer rate constant (ks) and diffusion coefficient (D) are measured. As a result, when EG is used, the solubility of 2,7-AQDS increases from 0.3 to 0.8 M in KCl solution and PVP acts as a barrier preventing the production of iodine gas that is a product generated by the side reaction of KI. The increase in solubility by the use of EG is because it has two hydroxyl groups and they form hydrogen bonding with the oxygen of sulfonyl or carbonyl group within 2,7-AQDS, while the alkyl group of its backbone that is in non-polar nature interacts with the phenyl group within 2,7-AQDS. In addition, EG increases the redox activity of KI because this significantly increases the nucleophilic ability of the iodide anion. Regarding the effect of PVP, when PVP is added to the solution containing iodine gas, povidone-iodine complex is formed and this complex impedes the side reaction of KI and maintains iodate that is a reactant for redox reaction as it is in the system. With that, when the AORFB using the 2,7-AQDS and KI including EG and PVP is run for ten cycle, it shows excellent performances like the discharge capacity of 0.7 AhL−1 and the coulombic and energy efficiencies of 98% and 82%.

Anomalous Light Scattering in Aqueous KCl Solutions

Molecular light scattering in dilute aqueous potassium chloride solutions has been studied. Anomalous (additional) molecular scattering of light is experimentally detected in the concentration interval from 0.001 to 0.004 mole fractions of the electrolyte. The obtained data are compared with the literature data on light scattering in aqueous and non-aqueous solutions of potassium chloride. The absence of additional scattering in the previous works was substantiated.

Solvation thermodynamics of anti-tuberculosis Isoniazid in aqueous and in aqueous electrolytic media

Abstract Isoniazid forms one of the most potent antitubercular drugs effective against M. tuberculosis which functions in combination with pyrazinamide, rifampicin and ethambutol drugs. A drug is subjected to many complex processes from the time it is administered to the time the biologic response is affected. The physical properties give an idea of various types of interactions taking place between drug and water molecule. Keeping this in mind we have measured densities (ρ) and speeds of sound (u) of Isoniazid (INH) in aqueous, aqueous sodium chloride and potassium chloride (0.06 mol·kg−1 and 0.1 mol·kg−1 in water) at three different temperatures i.e. T = (288.15, 298.15 and 308.15) K in the concentration range of (0.01 to 0.1) mol·kg−1. From these experimental data, apparent molar volume ( V ϕ ) of solute, isentropic compressibility ( κ s ) of solution, apparent molar isentropic compressibility ( κ ϕ ) of Isoniazid (INH) in water and in aqueous solutions of 0.06 and 0.1 mol·kg−1 sodium chloride and potassium chloride have been calculated. The limiting apparent molar expansivity ( E ϕ 0 ) of solute and coefficient of thermal expansion ( α ∗ ) of Isoniazid (INH) have also been calculated. Transfer parameters have been interpreted from the point of view of concentration dependence of solute–solvent interactions. Infinite dilution values of V ϕ and κ ϕ have also obtained from extrapolation to zero molality and have been utilized in obtaining transfer volumes ( Δ tr V ϕ 0 ) and transfer compressibility ( Δ tr κ ϕ 0 ) of Isoniazid (INH) from aqueous solutions of 0.06 mol·kg−1 and 0.1 mol·kg−1 sodium chloride and potassium chloride at different temperatures. Results are used to analyze the nature of solute-solvent, solute-solute interaction and structure making/breaking ability of solute in the aqueous solution.

The Effect of Interdigitated Channel and Land Dimensions on Flow Cell Performance

We demonstrate the effect of varying the channel and land width dimensions of an interdigitated flow field experimentally and through computational modeling. Measured polarization curves (overpotential versus current density) are reported for a symmetric cell with a ferrocyanide-ferricyanide electrolyte in aqueous potassium chloride. A two-dimensional, coupled fluid dynamic and electrochemical model is developed to interpret polarization results from the symmetric cell. This model suggests that stagnant fluid zones above the center lines of the interdigitated channels negatively impact cell performance. A three-dimensional computational fluid dynamic model is used to calculate the pressure drop and power losses associated with flowing fluid through these flow fields. The voltage efficiency of the cell, corrected for pumping power losses, is evaluated and reported as a function of channel and land width to identify high-efficiency flow fields. The implications for the engineering of large-area flow fields are discussed.

Microwave-assisted micro-encapsulation of phase change material using zein for smart food packaging applications

Novel zein/tet (tetradecane) and zein/tet/APC (aqueous potassium chloride) micro-encapsulated functional materials were synthesized using a microwave-assisted encapsulation technique. This technique can produce microcapsules in a very short time. In this study, we optimized the methodology used to obtain micro-encapsulation structures based on zein (a maize protein). Zein was mixed with functional materials in ratios of 1:1 and 1:2 (w/v) using ethanol as a solvent. After sonication, each mixture was treated up to 550 s at a power of 450 W in a microwave oven. Subsequently, nitrogen was pumped into the solution for 1 h to remove any residual ethanol from the system and the samples were freeze-dried to yield the dry powder. The thermal performance was analyzed using differential scanning calorimetry and thermogravimetric analysis. The encapsulation morphology and chemical structure were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Tetradecane was found to be properly encapsulated in the microstructure of zein under two different conditions with an average capsule diameter of 13950 nm. The melting point, crystallization point, and latent heat of encapsulated zein/tet are 4.95, 0.68 °C, and 107 J g−1, respectively. Thermal cycling tests indicated that zein/tet and zein/tet/APC have good thermal stability with negligible changes in their melting and crystallization temperatures. Heat management with tet has been modified using potassium chloride to support a suitable temperature range for food packaging. The encapsulated materials can be potentially used for temperature control during the transport of temperature-sensitive products.

Online Alkali Measurement during Oxy-fuel Combustion

Coal has been the main fuel in the generation of heat and power for many years and will continue to be so for years to come. Global warming awareness has led to the Kyoto Protocol, which targets the abatement of six greenhouse gases, including carbon dioxide (CO2). For the abatement of CO2 emissions, co-combustion of coal and biomass is an attractive solution. Other mitigation solutions include oxy-fuel combustion followed by Carbon Capture and Storage (CCS). However, co-combustion with coal and biomass in oxy-fuel atmosphere has been found to be conducive to chlorine-induced corrosion, slagging and fouling due to the use of complex fuel mixtures rich in alkali metals and chlorine. In order to address problems such as high-temperature corrosion, slagging and fouling caused by the use of these types of fuel mixtures, an alkali-measuring device is needed. The In-situ Alkali Chloride Monitor (IACM) utilizes UV light and Differential Optical Absorption Spectroscopy to measure gas-phase potassium chloride (KCl). This device has been successfully employed during biomass (wood chips and demolition wood) combustion and waste incineration. To investigate its performance in oxy-fuel combustion, the instrument was mounted on a 100 kW oxy-fuel combustion test unit equipped with a propane burner and a system for seeding of aqueous potassium chloride solution. The unit was operated in air- and oxy-fuel mode and the experiments substantiated the feasibility of online monitoring of gas-phase KCl in the flue gas during oxy-fuel combustion. The employment of an online alkali monitoring device during oxy-fuel combustion has the potential to increase the understanding of the release and capture of alkali chlorides, which in turn opens up for mitigation methods to reduce high temperature corrosion, slagging and fouling. This is a cost-efficient, sustainable solution because it extends the operational time of the boiler, reducing related maintenance costs.

Role of electrolytes in the solubility of l-proline and its transfer free energetics

Solubility of the amino acids in aqueous electrolytes plays a major role in influencing their solvation thermodynamics which is further associated with their biochemical and biophysical deeds in human physiology. In the present study the solubility of l-proline in aqueous sodium chloride (NaCl), sodium nitrate (NaNO3), potassium chloride (KCl) and potassium nitrate (KNO3) solutions were determined in five equidistant temperatures by using an analytical ‘gravimetric’ method. The experimental results were compared with that of the earlier in order to explain the factors playing the role during the course of solvation of l-proline in the experimental electrolytes solutions. Related thermodynamic and molecular properties such as standard transfers Gibbs energetics, molar volume, density, dipole moment and solvent diameter of the experimental solutions were also evaluated in this study. The above mentioned factors were applied to find out the chemical effects of the transfer Gibbs energies. Different factors such as nature of the solute, interactions between solute and solvents, etc., were characterized by using different physical and analytical loom.

Thermodynamics of DL-α-aminobutyric acid induced solvation mechanism in aqueous KCl solutions at 288.15–308.15 K

The solubilities of DL-α-aminobutyric acid in KCl solutions of different concentrations are measured at 288.15–308.15 K. Gibbs energies and entropies have been determined for transfer of α-aminobutyric acid form water to aqueous KCl solution at 298.15 K. The cavity, dipole-dipole and other interactions affecting the solubility, as well as stability of the amino acid in solution are also evaluated. Gibbs energy and entropy of transfer due to interactions are computed to create the model of the complex solute-solvent and solventsolvent interactions. Molar volume, densities, dipole moment of solvent and diameter of co-solvent in aqueous potassium chloride are also evaluated.

Mean Activity Coefficients and Osmotic Coefficients in Dilute Aqueous Sodium or Potassium Chloride Solutions at Temperatures from (0 to 70) °C

Two-parameter Huckel equations have been determined for the activity coefficient of the salt and for the osmotic coefficient of water in aqueous NaCl or KCl solutions at 0 °C from the highly accurate freezing point data of Scatchard and Prentiss (J. Am. Chem. Soc. 1933, 55, 4355–4362), and points were taken in the estimation up to a molality of 0.5 mol·kg–1. This molality is the upper limit for the use of the data from this method without any corrections to determine thermodynamic activity values for a constant temperature of 0 °C. The electrolyte parameters of the Huckel equation are B and b1, and the value obtained for parameter B in the case of both salts is closely the same as that determined in a previous NaCl and KCl study (Partanen, J. I.; Covington, A. K. J. Chem. Eng. Data 2009, 54, 208–219) from the isopiestic and cell potential difference (cpd) data at 25 °C. The resulting parameters were tested with the other precise freezing point data existing in the literature for these salts and with the c...

Solubility and Chemical Thermodynamics of d,l-Alanine and d,l-Serine in Aqueous NaCl and KCl Solutions

The solubilities of d,l-alanine and d,l-serine in aqueous sodium chloride (NaCl) and potassium chloride (KCl) solutions are determined at five equidistant temperatures by using “formol titrimetry”. The thermodynamic parameters such as standard transfer Gibbs energies, entropies, and enthalpies have been evaluated at 298.15 K. Other important related parameters like molar mass, density, molar volume, dipole moment, and solvent diameter, etc., of the experimental solutions are also determined in the present study. ΔGt,ch0(i), i.e., chemical effects of the transfer Gibbs energies, and TΔSt,ch0(i), i.e., chemical effects of the transfer entropy of these amino acids, are also evaluated and discussed, the factors which are dependent on mainly nature of the solute, solvent, interactions between solute and solvent, etc. The nature and the extent of the involved factors, which are influencing the solvation of the amino acids in aqueous NaCl and KCl solutions, are also explained by the different physical and analyt...

Thermodynamics and mechanisms of glycine solvation in aqueous NaCl and KCl solutions at 298.15 K

In the present study the solubility of glycine in aqueous sodium chloride and potassium chloride solution was determined under different experimental conditions using ‘formol titrimetry’ method. The thermodynamic parameters like standard transfer Gibbs energies and entropies have been evaluated at 298.15 K. Other important parameters like molar volume, densities, solvent diameter, etc., of the experimental solutions have also been determined in this study. The above mentioned parameters have been used to determine ∆t,ch0(i)i.e., chemical effects of the transfer Gibbs energies and T∆t,ch0(i)i.e., chemical effects of the transfer entropy. The solvation of glycine is influenced by different factors such as nature of the solute, interactions between solute and solvents, etc., which has been explained by different physical and analytical approach.

Increased Power Conversion Efficiency of Dye-Sensitized Solar Cells with Surface-Modified Photoelectrode

A nanoporous TiO2 film was modified with an aqueous potassium chloride (KCl), and the resulting film was applied to the photoelectrode of dye-sensitizes solar cell (DSSC). The DSSC with KCl-modified photoelctrode showed an increase in short circuit current (Jsc) and open circuit voltage (Voc), resulting in a power conversion efficiency (PCE) of 7.04%, compared to that (6.36%) of reference device with bare TiO2. The suppression of charge recombination between photo-injected electrons and triiodide (I3−) ions was found to increase both Jsc and Voc of the device with KCl-modified photoelctrode.

Nonphotochemical Laser-Induced Crystal Nucleation by an Evanescent Wave

Crystal nucleation at a glass–solution interface has been demonstrated by evanescent-wave laser-induced nucleation for the first time. Nucleation was induced in supersaturated aqueous potassium chloride (KCl) solutions. The interaction volume was estimated to be <2 nL, localized within approximately 100 nm of the interface. Measurements of the power dependence of nucleation events showed a laser power threshold that was approximately 3 times higher than that in experiments in bulk solution; the average number of nucleation events above threshold was similar to that in bulk. Surfaces treated with a hydrophobic polydimethylsiloxane-based coating showed no nucleation over the coated regions. The localization offered by this method has significant potential benefit for studies of the nucleation mechanism or for patterning of crystal nuclei in two dimensions.

Solubility and solvation thermodynamics of dl-nor-valine in aqueous solutions of NaCl and KCl

Solubility of amino acids in aqueous solutions plays a major role in determining their thermodynamics of solvation which is further related to their biochemical and biophysical actions in human physiology. In the present study the solubility of dl-nor-valine in aqueous sodium chloride and potassium chloride solution was determined in five equidistant temperatures by using ‘formol titrimetry’ method. The thermodynamic parameters such as standard transfer Gibbs energies and entropies have been evaluated at 298.15K. Other important related parameters like molar volume, density, dipole moment and solvent diameter of the experimental solutions were also determined in this study.The above mentioned parameters were used to determine ΔGt,ch0(i) i.e. chemical effects of the transfer Gibbs energies and ΤΔSt,ch0(i) i.e. chemical effects of the transfer entropy. Different factors such as nature of solute and solvent, interactions between solute and solvents, etc., influencing the solvation of dl-nor-valine were characterized by different physical and analytical approaches.

Characterization of 2D colloid aggregations created by optically induced electrohydrodynamics.

Rapid electrokinetic patterning (REP) is a technique for creating self-assembled monolayers (SAMs) of spherical particles in a liquid medium, and dynamically controlling them though the simultaneous application of an electric field and optically induced temperature gradients. Previous work has investigated and characterized REP axisymmetric aggregations generated from a focus laser within a uniform electric field; work herein characterizes line-shaped particle assemblies derived from the application of a linearly scanned laser. The resulting aggregations of spherical polystyrene particles (1 μm) suspended in low-conductivity aqueous potassium chloride solution (KCl, 2.5 mS/m) resembled elliptical-shaped crystalline geometries. The mean particle-to-particle spacing within the aggregation remained greater than 1.5 diameters for experiments herein (6.5 Vrms , 30 kHz) due to dipole-dipole repulsive forces. Interparticle spacing demonstrated a linear relationship (1.6-2.1 μm) with increasing scanning lengths (up to 83 μm), decreased from 1.9 to 1.7 μm with increasing scanning frequency (0.38-16 Hz) for a 53 μm scan length, and decreased from 2.0 to 1.6 μm with increasing laser power (11.9-18.8 mW) for a 59 μm, 16 Hz laser scan.

Limiting Conductivities of Univalent Cations and the Chloride Ion in H2O and D2O Under Hydrothermal Conditions

Frequency-dependent electrical conductivities of aqueous sodium chloride, potassium chloride, cesium chloride, potassium iodide and cesium iodide have been measured in both H2O and D2O between T = 298 and 598 K at p ~ 20 MPa at a ionic strength of ~10−3 mol·kg−1 using a high-precision flow-through AC electrical conductance instrument. Experimental values for the molar conductivity, Λ, of each electrolyte were used to calculate their molar conductivities at infinite dilution, Λ°, with the Fuoss–Hsia–Fernandez-Prini conductivity model. Single-ion limiting conductivities for the chloride ion in H2O, λ°(Cl−), were derived from Λ° by extrapolating literature values for the transference number of Cl−, t°(Cl−), in aqueous solutions of KCl and NaCl from ~400 and ~390 K up to the experimental conditions. Values for λ°(Cl−) in D2O were determined from literature values of t°(Cl−) for KCl in D2O near ambient conditions, assuming the same temperature dependence as in H2O. The results were used to calculate values for the single ion limiting conductivities λ°(Na+), λ°(K+), λ°(Cs+), λ°(Cl−), and λ°(I−) in both light and heavy water. The values of λ° in D2O are the first to be reported at temperatures above 338 K. The temperature dependence of the isotopic Walden product ratio, \( (\lambda^\circ \eta )_{{{\text{D}}_{2} {\text{O}}}} /(\lambda {^\circ }\eta )_{{{\text{H}}_{2} {\text{O}}}} \), indicates that differences in the hydration of Cl−, K+ and Cs+ ions between light and heavy water at ambient conditions associated with hydrogen-bonding, the so-called “structure breaking” effects, largely disappear at temperatures above ~400 K. The value of \( (\lambda^\circ \eta )_{{{\text{D}}_{2} {\text{O}}}} /(\lambda {^\circ }\eta )_{{{\text{H}}_{2} {\text{O}}}} \) for the “structure making” ion Na+ rises from 0.98 at 298.15 K to ~1.04 ± 0.02 at temperatures above ~375 K and remains approximately constant up to 600 K.