Sodium Chloride Medium Research Articles

Dezincification of Brass in Sulfide Polluted Sodium Chloride Medium: Evaluation of the Effectiveness of 2-Mercaptobenzothiazole

Dezincification of Brass in Sulfide Polluted Sodium Chloride Medium: Evaluation of the Effectiveness of 2-Mercaptobenzothiazole

Interference by cerium cations during the multi-step zinc dissolution process in a chloride-containing electrolyte

The influence of cerium ions in the dissolution mechanism of zinc has been evaluated by means of electrochemical impedance spectroscopy in a sodium chloride media. The multi-step dissolution process of zinc is modified during the early stages of immersion. The initial chloride ions adsorption on the surface is hindered by the adsorption of cerium ions which act as a precursor of the rich cerium layer formed with time. This was revealed by the appearance of two constant times at high and intermediate frequencies related to the charge transfer resistance and the adsorption process. At longer times, 24 h, the second arc evolves toward a diffusion tail. As time increases the behaviour of the galvanised steel depends on the Ce concentration. For 500 and 1000 ppm CeCl 3 · 7H 2O there was no evidence of the constant time associated to the porous corrosion products of zinc at the high frequency range.

The inhibition effects of some cyclic nitrogen compounds on the corrosion of the steel in NaCl mediums

Corrosion inhibition efficiencies of 3-amino-1,2,4-triazole (3-ATA), 2-amino-1,3,4-thiadiazole (2-ATDA), 5-( p-tolyl)-1,3,4-triazole (TTA), 3-amino-5-methylmercapto-1,2,4-triazole (3-AMTA) and 2-aminobenzimidazole (2-ABA) on steel in sodium chloride media were investigated using Tafel extrapolation method. Potentiostatic current–potential curves were utilized to derive corrosion potentials ( E corr), corrosion current densities ( i corr), surface coverage degrees ( θ) and corrosion inhibition efficiencies ( η, %). 2-ABA was found to have the highest inhibition efficiency in both, 2.5 and 3.5% aqueous NaCl media. For all the inhibitors studied, surface coverage and inhibition efficiency values were found to increase with increasing concentration of the compound concerned. Inspection of the θ values indicate that the adsorption process obeys the Temkin isotherm for TTA and 2-ABA, but the Langmuir isotherm is followed by 3-ATA, 2-ATDA and 3-AMTA.

Analogy between the effects of a mechanical and chemical perturbation on the conductivity of passive films

In order to study the passivity breakdown of a type 316L stainless steel, the electrochemical impedance and surface stresses were measured under straining conditions. The Mott–Schottky analysis, performed at high frequency, appears as very useful method to study, below the apparent yield strength, the effects of a mechanical stress on the capacitance values. The results obtained in sodium chloride media indicate that the semiconducting properties of passive films formed in a tensile stress field reflect a higher vacancies concentration than those formed in a stress-free state, suggesting that the passive film conductivity is increased. It was also shown that the Mott–Schottky plots drop in the presence of tensile surface stresses, indicating that the passive film composition may be different from that formed in the presence of compressive surface stresses. A comparison between the effects of mechanical stresses and those of chloride is proposed.

An equilibrium model of the solubility of calcium oxalate in sodium chloride medium

An equilibrium model of the solubility of calcium oxalate in sodium chloride medium

Zinc desorption kinetics as influenced by pH and phosphorus in soils

The rate of zinc (Zn) desorption from soil surfaces into soil solution is a dynamic factor that regulates its continuous supply to growing plants. To ascertain the pattern of Zn desorption as a function of phosphorus (P) application rate and pH, kinetics of Zn desorption from three surface soils representative of three major benchmark soil series were investigated using four equations. Zinc desorption decreased continuously with increase in pH from 4.25 to 8.00 in Oxisol. By contrast, Alfisol and Vertisol exhibited maximum Zn desorption at pH 5.50. Thereafter, Zn desorption decreased abruptly at pH 6.75 and finally steady state condition was obtained in both sodium chloride (NaCl) and calcium chloride (CaCl2) medium. The Elovich equation described Zn desorption kinetics much better at pH 4.25 and 5.50 followed by Parabolic diffusion equation at pH 6.75 and 8.00 for all the soils in NaCl medium. Whereas in the CaCl2 medium, the Elovich equation was superior in fitting the Zn desorption data irrespective of P level, pH, and soil. The Elovich constant (β) indicated that P affects Zn desorption inversely up to pH values 6.75.

Evaluation of cadmium–metallothionein stability constants based on voltammetric measurements

A voltammetric study on the binding properties of the commercially available rabbit liver metallothionein (MT) Sigma M 7641 for cadmium ions was performed. The capacity of metallothionein to complex cadmium and the stability constants of Cd–T complex (T denotes the apoprotein or thionein molecule) have been determined from the direct titration of the defined MT concentration with the standard CdCl 2 solution in 0.59 M sodium chloride medium at pH 7.9 and 2.0. At pH 7.9 the formation of the Cd–T complex has been followed measuring the specific anodic signal height of the complex. Stability constants of Cd–T have been evaluated from the experimental data using three different procedures. The calculated apparent stability constants K=(7.6±0.2)·10 8 dm 3 mol −1 of Cd–T complex in 0.59 M NaCl at pH 7.9 and 25°C indicate that under the given experimental conditions all the three procedures are equally applicable.

Solubility of calcium oxalate in the presence of magnesium ions, and solubility of magnesium oxalate in sodium chloride medium

Article Solubility of calcium oxalate in the presence of magnesium ions, and solubility of magnesium oxalate in sodium chloride medium was published on December 1, 1999 in the journal Nordic Pulp & Paper Research Journal (volume 14, issue 4).

SYNERGISTIC EFFECTS IN SOLVENT-EXTRACTION SYSTEMS BASED ON ALKYLSALICYLIC ACIDS. III. EXTRACTION OF THE TRIVALENT LANTHANIDES AND YTTRIUM FROM CHLORIDE MEDIA IN THE PRESENCE OF DIALKYL AND DIARYL SULPHOXIDES

ABSTRACT DialkyI and diaryl sulphoxides were found to cause synergistic shifts in the pH50 values for the extraction of the trivalent lanthanides and yttrium from sodium chloride media by solutions of alkylsalicylic acids in xylene. The extent of the synergistic shift for a given sulphoxide increases with increasing steric bulk of the alkylsalicylic acid used. With the homologous series of dialkyl sulphoxides R2SO, where R = n-butyl, n-hexyl, and n-octyl, there is little variation in the size of the synergistic shift for a given alkylsalicylic acid. For a series of sulphoxides containing similar numbers of carbon atoms, the extent of the shift increases with the introduction of alicyclic rings, but decreases when aromatic rings are introduced, for example, in the order of R: cyclohexyl > n-hexyl > phenyl, although the effect is not very marked. For a given extractant mixture, the pH50 values decrease from lanthanum to samarium and then increase from samarium to lutetium. The separation between the pH50 values for lanthanum and lutetium increases with increasing steric bulk of both the alkylsalicylic acid (HA) and the sulphoxide (L), but the separations between adjacent lanthanides are in all cases too small to be of any practical use. Slope-analysis treatment of metal-distribution data, and measurements of the solubility of the neodymium-alkylsalicylic acid complex in xylene solutions of the sulphoxides are consistent with the extraction of a mixed-ligand complex of the type NdA3L2.

ChemInform Abstract: Hydrolysis of the Zinc(II) Ion in Sodium Nitrate, Chloride and Perchlorate Medium: The Effect of the Anionic Medium.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Extracción de Ag(I) en medio cloruro sódico con sulfuro de tri-isobutil fosfina

The solvent extraction of Ag(I) from concentrated sodium chloride solutions by the extractant tri-isobutyl phosphine sulphide is studied. Silver is extracted from this sodium chloride media by means of a solvation reaction, the stoichiometry of the extracted species is related to an extractant: Ag molar relationship of 2. Silver extraction by menas of TIBFS is related to exothermic extraction reactions this behaviour independent both of the aqueous media and the organic diluent. The extraction system is selective with respect to the presence of Cu and Zn in the aqueous phase. Silver is stripped by sodium tiosulphate solutions. Values of log Kext ΔGo and ΔSo a 25 °C for the present extraction system were also given.

Jet electrochemical etching of nickel in a sodium chloride medium assisted by a pulsed laser beam

This paper deals with the jet electrochemical etching of metal, using nickel drilling as an example; the performance of this technique was investigated as a function of the nozzle diameter and current density. The significance of the outer dissolution of metal, due to liquid spreading on the vertical substrate facing the nozzle, was estimated; the hole size was compared to the nozzle diameter. Moreover, a pulsed beam was shown to improve the precision of the edge. Applications to shape patterning are presented and discussed.

Hydrolysis of the zinc(II) ion in sodium nitrate, chloride and perchlorate medium: the effect of the anionic medium

Hydrolysis of the zinc(II) ion in 0.5 mol dm–3(Na)NO3, (Na)Cl or (Na)ClO4 solution was studied by the electromotive force method at 25 °C. The data cover the zinc(II) concentration range 2.5–40 mmol dm–3 within the pH range 2.0–6.0. The general least-squares treatment of the data indicates the formation of only mononuclear complexes. The complex [Zn(OH)]+ was found in all three media, while Zn(OH)2(aq) was found only in perchlorate solution. This, as well as the differing values for the stability constant of [Zn(OH)]+, demonstrate the effect of the anionic medium on both complex formation and stability of the hydrolytic species.

Thiol compounds as corrosion inhibitors of carbon steel (XC 38) in sodium chloride medium

AbstractThe study of thio compounds as inhibitors against the corrosion of a carbon steel (XC 38) in contact with 3% sodium chloride using a rotating disk electrode was performed. Stationary and transient measurements were carried out. Inhibition efficiency was estimated from both current‐potential characteristics and gravimetric measurements. With the most efficient inhibitor, orthoaminothiophenol (OATP), the inhibition mechanism was studied. Interpretation of the results implies the formation of a thick and compact inhibitor film. The OATP acts by considerably reducing the active area without modifying the mechanism of anodic and cathodic processes.

Improved isolation of normal human reticulocytes via exploitation of chloride-dependent potassium transport

Studies on normal human reticulocytes have been limited by a lack of methods for effective reticulocyte enrichment. This study shows a convenient new approach for selective enrichment of reticulocytes from normal blood samples. We have developed a modified arabinogalactan density gradient that contains high potassium levels, approximating the internal cation composition of red blood cells (RBC). The low-density populations from this gradient are enriched in reticulocytes, and the highly selected lowest density fraction shows a much higher reticulocyte enrichment than that obtained with high sodium chloride arabinogalactan density gradients, or other previously reported density gradient methods. We found that this improved isolation is caused by suppression of potassium loss and reticulocyte dehydration via chloride (KCI) cotransport. When the low-density fraction of RBC from a high-potassium gradient was subsequently incubated in high sodium chloride medium and reseparated on a sodium chloride density gradient, the reticulocytes dehydrated and were recovered in high-density fractions. The highest-density fractions from this secondary gradient yield 95% to 99% reticulocytes. We anticipate that this method will benefit investigators who require reticulocyte enriched populations for a wide variety of applications.

Improved Isolation of Normal Human Reticulocytes Via Exploitation of Chloride-Dependent Potassium Transport

Abstract Studies on normal human reticulocytes have been limited by a lack of methods for effective reticulocyte enrichment. This study shows a convenient new approach for selective enrichment of reticulocytes from normal blood samples. We have developed a modified arabinogalactan density gradient that contains high potassium levels, approximating the internal cation composition of red blood cells (RBC). The low-density populations from this gradient are enriched in reticulocytes, and the highly selected lowest density fraction shows a much higher reticulocyte enrichment than that obtained with high sodium chloride arabinogalactan density gradients, or other previously reported density gradient methods. We found that this improved isolation is caused by suppression of potassium loss and reticulocyte dehydration via chloride (KCI) cotransport. When the low-density fraction of RBC from a high- potassium gradient was subsequently incubated in high sodium chloride medium and reseparated on a sodium chloride density gradient, the reticulocytes dehydrated and were recovered in high-density fractions. The highest-density fractions from this secondary gradient yield 95% to 99% reticulocytes. We anticipate that this method will benefit investigators who require reticulocyte enriched populations for a wide variety of applications.

Evidence for stimulation of the K-Cl cotransport system by phenazine methosulfate

The effects of phenazine methosulfate (PMS), a known generator of oxygen free radicals, on ion transport in human erythrocytes were studied. The treatment of the red blood cells with 0.1–0.8 mM PMS caused the concentration-dependent increase of K loss from the cells in K-free sodium chloride medium. The PMS-dependent K efflux from the cells in oxygen-free medium, being in equilibrium with argon, did not differ from the control. After substitution of Cl − ions in the medium by NO 3 −, PMS caused only a small activation of K loss. PMS at a concentration of 0.8 mM was found to increase passive K transport in erythrocytes (ouabain-furosemide-resistant 86Rb influx) and at the same time to decrease active transport of K (ouabain-sensitive influx of 86Rb). Furosemide-sensitive cotransport of K was not affected by 0.8 mM PMS. The influx of 22Na in the red blood cells was also independent of the presence of 0.2–1.0 mM PMS in the bath medium. The results obtained suggest that PMS stimulated the reversible K-Cl cotransport in human erythrocyte membranes. This effect of PMS resembles the action of the well-known SH-alkylating agent, N-ethylmaleiroide.

Influence of calcium/sulfate molar ratio on the growth rate of calcium sulfate dihydrate at constant supersaturation

The growth kinetics of calcium sulfate dihydrate (CSD) has been investigated using the constant composition method over a range of calcium/sulfate molar ratios, r, in supersaturated solutions (0.17< r<5.0, at ionic strength, I=0.500m with potassium chloride as the supporting electrolyte and 0.08< r<10.0 at I=1.00m in sodium chloride medium). In spite of constancy of ion activity product, the rate increases with decreasing Ca/SO 4 molar ratio, indicating that the rate of crystal growth is not merely a function of the thermodynamic driving forces but also depends upon the relative concentrations and characteristics of individual lattice ions.

Effect of acetate and EDTA ligands on Hydrolysis of the Iron(III) Ion in sodium chloride medium

AbstractThe hydrolysis of the iron(III) ion in sodium chloride medium without organic ligands and in the presence of acetate and EDTA ligands was studied by emf method, at 25°C. The data indicate the effect of the organic ligands. In the presence of acetate ion the beginning of hydrolysis of the iron(III) ion is slightly shifted toward lower pH values, while in the presence of EDTA, as a strong complex forming ligand, the beginning of hydrolysis is shifted toward higher pH values for 2.5 pH units.

Effects of impermeant medium ions on the composition of rabbit renal cortical slices.

When incubated in isosmotic oxygenated medium in which chloride was completely replaced by gluconate, rabbit renal cortical slices lost chloride with sodium, potassium and water before reaching a new steady-state composition after 15-30 min. When corrected for extracellular space, there was an electroneutral loss of alkali metal cations (Na + K) with chloride, accompanied by isosmotic loss of water from the cells. The losses of chloride and water were independent of medium pH over the range of 6.4-8.2, and were the same with potassium rather than sodium as the dominant medium cation. Incubation in isosmotic sodium chloride medium restored tissue composition of slices transferred from gluconate medium. This recovery was not dependent specifically upon medium chloride, for slice water content also recovered when nitrate rather than chloride was substituted for medium gluconate. With sodium completely replaced by n-methyl d-glucamine (nmdG+), cells in slices lost far more sodium and potassium than chloride before reaching a new steady-state composition after some 30 min. However, the loss of water was as predicted from the total losses of measured inorganic ions. With sodium and chloride completely replaced by nmdG+ and gluconate, there was a greater loss of water than found with unilateral substitutions. Again, the combined loss of diffusible inorganic cations exceeded the loss of chloride but the water loss was that expected for isosmotic loss accompanying the measured losses of ions. These results reveal that both gluconate and nmdG+ behave as impermeant ions in this tissue preparation. It is suggested that, in the absence of medium sodium, sodium-hydrogen exchange is inhibited. Retained hydrogen ions are buffered on charged cellular non-diffusible solutes and the associated hydroxyl (or bicarbonate) ions are lost from the cells accompanied by the inorganic univalent cations lost in excess of chloride in nmdG+ medium.