Solutions Of Different Electrolytes Research Articles

Chemical Etching of Cu98Be Alloy in Electrolyte Solutions

The process of chemical etching of Cu98Be alloy in solutions of various compositions was investigated. The rate of etching of beryllium bronze in the investigated solutions was deter-mined, and its change in time was studied. The selectivity of dissolution of the components of Cu98Be during prolonged etching in solutions of different electrolytes was established. A possibility of achieving uniform etching of Cu98Be alloy by varying the composition of the etching solution was shown. The concentrations of metal ions in the used etching solutions were determined, and the capacity of those solutions was calculated. The compositions of solutions with a high capacity for both alloy components during prolonged etching was estab-lished. The optimal compositions of etching solutions providing high-quality etching of beryl-lium bronze according to several criteria such as: a high process rate, uniform dissolution of alloy components, high capacity for both alloy components were proposed. The morphology of the Cu98Be electrode surface after etching in solutions, providing uniform dissolution for both alloy components, was studied. The absence of surface passivation after chemical etch-ing in these solutions was shown. The chemical nature of the compounds formed in the form of small inclusions on the etched surface of the electrode was established. The obtained results are of great importance in practical use because they allow selecting the appropriate composition of the etching solution, which, in turn, helps to optimize the technological etching process.

Volumetric, compressibility and viscometric properties of diphenhydramine hydrochloride in aqueous solutions of electrolytes: An insight into interactional characteristics

The density (ρ), speeds of sound (u), and viscosity (η) measurements for diphenhydramine hydrochloride (anti histaminic drug) in aqueous solutions of different electrolytes (NaCl, KCl, RbCl, MgCl2, CaCl2 and SrCl2) have been carried out. Volumetric and compressibility properties of aqueous drug solution containing electrolyte have been explained on the basis of trends observed in different enumerated parameters and information regarding various solute–solvent interactions prevailing in the ternary system have been accessed. The effect of drug concentration and temperature on the interactional behaviour of the considered system has been analyzed by carrying out the experiments at different drug content (0.03–0.17 mmol.kg−1) and temperatures (298.15–313.15) K at definite interval of 5 K. The participation of specific as well as non-specific interactions between diphenhydramine hydrochloride (DPH) and electrolytes in aqueous solution has been found to play its role in stabilization of solution mixture. Further, the structural changes induced by drug molecules in solution containing different electrolytes with same concentration have been illustrated with the help of viscosity studies. The results obtained from different employed studies have been used to elucidate solute/solvent–solvent/solute interactions in aqueous electrolytic solution. As electrolytes are integral part of biological system, hence, the study of such systems may be very useful in understanding the mechanism of drug action that ultimately facilitates the illustration of drug – electrolyte chemistry.

Counterion‐Dictated Self‐Cleaning Behavior of Polycation Coating upon Water Action: Macroscopic Dissection of Hydration of Anions

AbstractThe counterions of polydiallyldimethylammonium (PDADMA) coatings were altered by incubation in aqueous solutions of different electrolytes. Oil de‐wetting on the resulting polycationic surfaces upon water action exhibited a straightforward connection with the Jones–Dole viscosity B‐coefficient (Bη) sign of surface counteranions. Upon water action, surface counteranions with negative Bη render PDADMA coatings oil‐adhering, but those with positive Bη furnish PDADMA coatings with excellent self‐cleaning. The oil‐adhering PDADMA surfaces can become self‐cleaning upon water action in response to the Bη of surface counteranions sign‐switching with increasing water temperature. Courtesy of surface counter‐anions with Bη>0, self‐cleaning PDADMA coatings enable not only conversion of conventional meshes into self‐cleaning membranes for oil/water separation, but also regioselective maneuver of oil flow on polycationic surfaces according to the Bη sign of surface counteranions patterned atop.

Counterion-Dictated Self-Cleaning Behavior of Polycation Coating upon Water Action: Macroscopic Dissection of Hydration of Anions.

The counterions of polydiallyldimethylammonium (PDADMA) coatings were altered by incubation in aqueous solutions of different electrolytes. Oil de-wetting on the resulting polycationic surfaces upon water action exhibited a straightforward connection with the Jones-Dole viscosity B-coefficient (Bη) sign of surface counteranions. Upon water action, surface counteranions with negative Bη render PDADMA coatings oil-adhering, but those with positive Bη furnish PDADMA coatings with excellent self-cleaning. The oil-adhering PDADMA surfaces can become self-cleaning upon water action in response to the Bη of surface counteranions sign-switching with increasing water temperature. Courtesy of surface counter-anions with Bη>0, self-cleaning PDADMA coatings enable not only conversion of conventional meshes into self-cleaning membranes for oil/water separation, but also regioselective maneuver of oil flow on polycationic surfaces according to the Bη sign of surface counteranions patterned atop.

Study on the Swelling Characteristics of Bamboo Based on Its Graded Hierarchical Structure

To understand the swelling characteristics of bamboo under its gradient structure, different parts of bamboo specimens have been soaked in solutions of different electrolytes. The results showed that the swelling extent of bamboo in solution is mainly influenced by chemical activity and molecular dimension of the solute. The dimensional increase in bamboo after swelling is mainly observed in the tangential and radial direction, and the largest dimensional increase as a result of swelling occurred in intermediary bamboo. High-concentration strong electrolytes will cause a certain degree of recrystallization in the bamboo specimen, especially in intermediary bamboo, resulting in an increase in its mass. In summary, the conclusion is that the removal of wax and tabaxir before swelling and the avoidance of using strong electrolytes as swelling solutions tend to improve the efficiency of swelling bamboo.

Suppression of the coalescence of gas bubbles in aqueous electrolyte solutions: dependence on the external pressure and velocity of gas flow through a column with liquid

An experiment on laser diagnostics of gas bubbles moving in aqueous solutions of different electrolytes has revealed that efficient suppression of gas bubble coalescence (collapse) occurs at certain concentrations of cation−anion pairs. It is experimentally proven that there is an optimal ion composition at which the coalescence is suppressed in a wide range of velocities of gas particle flow through a column with liquid. It is shown that the threshold ion concentrations corresponding to the onset of coalescence suppression decrease with an increase in the external pressure in the liquid. The results obtained can be used in oil production technologies to solve the problem of burning associated oil gas in torches.

Gels of cysteine/Ag-based dilute colloid systems and their rheological properties

The rheology of various systems consisting in L-cysteine, Ag, and aqueous solutions of different electrolytes has been studied. These systems can form gels at very low concentration of cysteine not exceeding 0.036 wt%. In periodic low amplitude oscillations, the gels behave as linear elastic media with frequency independent modulus and low mechanical losses in a wide frequency range. The modulus values lie in the range of 10–100 Pa. Meanwhile these systems demonstrate the dualism in the rheological behavior. In the stress-controlled shearing, “gels” behave not like elastic but like visco-plastic media. At low stresses, they flow with Newtonian viscosity of the order of 103–105 Pa s. However at some critical stress (“the yield stress”), the apparent viscosity falls by 6–7 decimal orders. Special rheological experiments demonstrated that this is not a bulk effect but most likely a consequence of the stream separation (“shear banding”). This effect is reversible and the thixotropic formation of the initial structure and properties takes place in the time-scale of the order of minutes. It was argued that the structural coagulation network is formed by the Ag nano-particles stabilized against sedimentation by L-cystine appeared as a result of the cysteine oxidation.

Redox capacitance of poly-3,4-ethylenedioxythiophene studied by cyclic voltammetry and faradaic impedance spectroscopy

The paper presents results of studying the electrochemical properties of poly-3,4-ethylenedioxythiophene films using the methods of cyclic voltammetry and faradaic impedance spectroscopy in acetonitrile and propylene carbonate solutions of different electrolytes: LiClO4, Bu4NBF4, Bu4NPF6. The effect of the film synthesis conditions, the nature of anion and solvent, and the supporting electrolyte concentration on the film redox capacitance is discussed. Main attention is paid to the comparison of values characterizing the redox capacitance of a poly-3,4-ethylenedioxythiophene film C lf (determined using the faradaic impedance method) and C cv (determined using the cyclic voltammetry method) and the studies of their dependence on the varied experimental factors. The experimental C lf vs. E curves are analyzed using the relationships of a model of a uniform film.

Ion exchange equilibrium between ion exchange membrane and electrolyte solutions

The ion exchange equilibrium between an ion exchange membrane and solutions of different electrolytes was studied. The matrix of the ion exchange membrane used consists of a vinyl polychloride network reinforced by a polyester screen; with quaternary and tertiary ammonium as functional groups. The data, provided by manufacturer, were completed by the experimental determinations of humidity percentage and ion exchange capacity. This paper focuses on the study of exchange reaction between an anion exchange membrane and selected binary and ternary electrolyte solutions. Experimental data are reported for the ion exchange equilibrium of the binary system Cl −/NO 3 −, Cl −/SO 4 2−, NO 3 −/SO 4 2− and the ternary system Cl − − NO 3 − − SO 4 2−. The ion exchange isotherms were established and affinity order of ions was given. The prediction of the ternary system based only on the binary data was consistent with the experimental data obtained for this system. Selectivity coefficients K Cl − NO 3 − , K 2Cl − SO 4 2− , K 2NO 3 − SO 4 2− were determined at ionic strength 0.1 M. Ion analyses were performed by ion chromatography, coupled to a conductimetric detector.

Effect of Electrolytes on the Aggregation of Sodium Dodecyl Sulphate: the Interactions of Different Counterions with Formed Micelles

Abstract The aggregation numbers (N) of sodium dodecyl sulphate (SDS) micelles in solutions of different electrolytes have been determined by the fluorescence quenching method. The micropolarity of SDS micelles in the presence of the electrolytes has been obtained from the intensity ratio of the third to the first peak in the fluorescence spectrum of pyrene. The results have been discussed against the experimental data obtained from electrospray ionization mass spectrometry. As far as we know, this method has not been used hitherto for interpretation of micelle–ion interactions. So, the electrostatic interactions of SDS monomers with different cations have been studied by electrospray ionization mass spectrometry (ESI-MS). It has been found that in the presence of both NaCl and NH4ClO4, the ions mainly localised close to the surface of SDS micelles are the sodium ones, while in the presence of KCl or Mg(ClO4)2, the ions mainly accumulating at the surface of SDS micelles and influencing the micelle size are K+ or Mg2+, respectively. Moreover, in the presence of KCl, a large number of the sodium counterions is also present at the micelle surface.

Swelling of Model Films of Cellulose Having Different Charge Densities and Comparison to the Swelling Behavior of Corresponding Fibers

Cellulose model films with different charge densities were prepared by spin-coating dissolved cellulose in N-methylmorpholine-N-oxide onto SiO2 surfaces. The swelling of the model cellulose films due to exposure to solutions of different electrolytes and at different ionic strengths and pH values were studied using QCM-D (quartz crystal microbalance with dissipation monitoring). Results show that at pH 5, there is a swelling of the film at a low electrolyte concentration (10-4−10-2 M), whereas the deswelling of the film was observed at a high electrolyte concentration (10-1−1 M). A considerable swelling of the films is seen when they are treated with deionized water with an increasing pH. The swelling of the films is accompanied by an increase in dissipation, that is, a softening of the material, and the deswelling by a decrease in dissipation, that is, a stiffening of the material. Furthermore, exposure of the films to solutions of different electrolytes affected the swelling of the layer. In this respect, the swelling response of Na2SO4 differs from that of NaCl and CaCl2 by showing simultaneously high swelling and low dissipation values. The results also show that the rate of swelling reaches its lowest value as the electrolyte concentration reaches the detected limit for the deswelling. The QCM-D results are compared to the swelling of the corresponding carboxymethylated fibers, where a similar behavior was found. However, for the fibers a marked deswelling occurred at a high electrolyte concentration, but only a minor deswelling of the cellulose film was observed. This difference between the materials can be ascribed to noncovalent bonds within the film that will not reform when the swelling forces are decreased at high electrolyte concentrations. A direct measurement of the thickness changes was performed using atomic force microscopy, which shows that the change in frequency measured with QCM-D for the films treated with different NaCl electrolyte concentrations corresponds to changes of 1−2%.

Application of luminescence methods in the study of the structure of aqueous electrolyte solutions

Abstract Luminescence methods have been applied to the study of solutions of concentrated aqueous electrolytes of LiCl, CaCl 2 , LiBr, CsCl with addition to those of LnCl 3 , NiCl 2 , MnCl 2 . The rate constants of energy transfer from Tb(III) ions to Er(III) ions to Er(III), Ni(II), Mn(II) were measured in solutions of different electrolytes. So as the energy transfer rate depends on the distance between the energy donor and acceptor, it can be shown from this study, that the labile nanostructures of lanthanide ions are formed in concentrated aqueous solutions of LiCl and to a lesser degree in solutions of CaCl 2 . The concentration of lanthanide ions in labile nanostructures is close to that of a saturated aqueous solution of LnCl 3 . The labile nanostructures consist of no less than several tens of lanthanide ions which exchange with ions of the solution during the time of less than one μs. The mixed labile nanostructures of lanthanide and Ni(II) or Mn(II) ions are also formed in concentrated LiCl solutions, but they are less stable. The dependence of labile nanostructure stability on temperature and on the addition to the electrolyte solution of other multicharge cations was also studied. The nature of the phenomenon of the labile nanostructure formation is discussed.

Role of ion hydration in the charge regulation at the surface of porous silica gel

By using potentiometric titration of a precisely characterised porous silica gel sample in solutions of different electrolytes, an attempt has been made to detect a possible manifestation of the spatial inhomogeneity caused by electrostatic saturation in the hydration potential of ions in the vicinity of a charged interface. Experimentally, an appreciable difference between the titration curves for different background electrolytes is observed. To determine whether this can be attributed to the difference in the hydration potentials of different ions and to obtain a theoretical estimate of the magnitude of the effect expected, the titration curves were simulated using a charge-regulation model based on the non-linear Poisson–Boltzmann equation with dielectric saturation being either neglected or allowed for. The distributions of surface charge density and surface potential over pore sizes for different pH and ion strengths have been calculated. It has been found that, although ‘switching on’ the dielectric saturation results in a noticeable reduction in the equilibrium surface charge density, the summed effect is hardly observable by potentiometric titration because of a concomitant increase in the amount of ion pairs. This suggests that the difference in titration curves may be attributed to a difference in the intrinsic association constants, characteristic of individual ion pairs.

Chromatographic studies of metal complexes. Part VI. Investigation of the effect of electrolytes on thin-layer chromatography

The octahedral cationic CoIII complexes [Co(ida)(bigH)2]+, [Co(glyO)(bigH)2]2+, [Co(α-alanO)(bigH)2]2+, [Co(β-alanO)BigH)2]2+ and Co(PhbigH)3]3+, where idaH2=iminodiacetic acid, glyOH=glycine, α-alanOH=α-alanine, β-alanOH=β-alanine and PhbigH=phenylbiguanide, were studied by thin-layer chromatography on silica gel in solutions of different electrolytes (NaCl, NaBr, NaI, Na2SO4, Na2S2O3, NaNO2 and NaNO3). Among other factors, the movement of the cationic complexes was found to be dependent on the surface tension and equivalent conductance of the developer electrolyte.

ATP-dependent and ATP-independent pathways of exocytosis revealed by interchanging glutamate and chloride as the major anion in permeabilized mast cells.

Most investigations of the mechanism of regulated exocytosis have involved the use of secretory cells permeabilized in glutamate-based electrolyte solutions. In our previous work we have used NaCl-based electrolyte solutions. For secretion to occur from rat mast cells under these latter conditions, a dual effector system comprising Ca2+ and a guanine nucleotide are required; together they are sufficient. Here we compare the secretion from mast cells permeabilized in solutions of different electrolytes. Replacement of Na+ by K+ had little effect. Replacement of Cl- by Br-, SO4-, gluconate, isethionate, acetate, tartrate, succinate, etc. affected the maximal extent of secretion elicited by the dual effectors Ca2+ and guanosine-5'-O-(3-thiotriphosphate) (Ca2(+)-plus-GTP-gamma-S) but had little influence on the effective affinity for Ca2+. The dicarboxylic amino acids (L- and D-glutamate, and L-aspartate) permitted exocytosis to be elicited by Ca2+ or GTP-gamma-S alone. Secretion stimulated by GTP-gamma-S is strongly inhibited by Cl- (50% inhibition by 20 mM Cl-), whereas the extent of Ca2(+)-induced secretion is proportional to the concentration of glutamate in mixed electrolyte buffers. Unlike dual-effector stimulation, secretion due to the single effectors requires adenosine triphosphate (ATP) and is prevented by inhibitors of protein kinase C. These results point to the existence of two parallel pathways for control of exocytosis in permeabilized cells, one ATP dependent, the other ATP independent.

Extraction of 1:1 electrolytes from aqueous solutions by resins containing dibenzo-18-crown-6 as anchor groups

The electrolyte concentration dependence of the distribution ratio of 1:1 electrolytes between resins containing dibenzo-18-crown-6 and water at 298 K was studied. The apparent equilibrium constants for the process taking place when the resin is equilibrated with aqueous solutions of different electrolytes are reported. The results obtained clearly reflect the influence of the anion on the extraction of cations by the resin containing the macrocyclic ligand.

Activity coefficients of hexamminecobalt(III) iodate in aqueous solutions of different electrolytes

Activity coefficients of hexamminecobalt(III) iodate in aqueous solutions of different electrolytes

Solubility of hexamminecobalt (III) hexacyanoferrate (III) in aqueous solutions of different electrolytes

The solubility of hexamminecobalt (III) hexacyanoferrate (III) in aqueous solutions of NaBr, KBr, NH 4Br, (CH 3) 4NBr, (C 2H 5) 4NBr, (C 4H 9) 4Br, NaCl, KCl, NH 4Cl, NaNO 3, NH 4NO 3, KNO 3, and NaI has been determined over an ionic strength range of 0.0003 to 0.18 mol · kg −1 at 298.15 K by a spectrophotometric method. Relative activity coefficients have been evaluated and compared with the predictions of the Debye-Hückel (DH) theory and the numerical integration of the Poisson-Boltzmann equation (IPBE). The predictions are in agreement with the experimental results for inorganic salts. Organic salts show a larger solubilizing effect and the activity coefficients of Co(NH 3) 6Fe(CN) 6 can be interpreted in terms of association between Fe(CN) 6 3− and tetraalkylammonium cations.

Activity coefficients of hexamincobalt (III) oxalate in aqueous solutions of different electrolytes

Relative activity coefficients of hexamincobalt (III)_oxalate, {Co(NH 3) 6} 2(C 2O 4) 3, in aqueous solutions of LiCl, NaCl, KCl, NH 4Br, NaBr, KBr, NH 4NO 3, KI, KSCN, (CH 3) 4NBr, (C 2H 5) 4NClO 4, and (C 4H 9) 4NI have been evaluated from solubility determinations over an ionic-strength range of 6×10 −3 to 0.19 mol kg −1 at 298.15 K. The analysis of the hexamincobalt (III) oxalate solutions were performed by measuring the optical density at 476 nm. Our results are compared with the predictions of the Debye-Hückel (DH) theory, the numerical integration of the Poisson-Boltzmann equation (IPBE), and the Mayer theory.

Solubility measurements of hexamincobalt(III) trimetaphosphate in aqueous solutions of different electroytes

The solubility of Co(NH 3) 6P 3O 9 in water and in solutions of different electrolytes has been measured at 25.0°C. In the presence of inorganic cations, the increase in solubility is that predicted by a simple Debye—Hückel equation, with an å parameter of the order of 6.1 (uni-univalent electrolytes) or 4.8 (multivalent electrolytes) Å. Very small differences of such parameters account for the observed specific effects of inorganic electrolytes. The increase of solubility in the presence of slats with a common ion can be interpreted in the same way. The numerical Integration of the Poisson—Boltzmann Equation (IPBE) predicts the same results as well. The organic cations have a much smaller solubilizing effect, which does not appear to be related with the ion size only.