Aqueous Solutions Of Inorganic Electrolytes Research Articles

Thermoelectric and Thermoelectrokinetic Effects in Colloid Systems that Simulate Biological Liquids of Living Organisms

Thermo- and thermoelectrokinetic emf and conductivity are experimentally determined for aqueous solutions the properties and composition of which are similar to human blood (Ringer solution, serum albumin, and Ringer solution with serum albumin). Effect of colloid particles contained in aqueous solutions of inorganic electrolytes on thermo-emf is analyzed. The experimental results show that the coefficient of thermo-emf of liquids based on the Ringer solution noticeably depends on temperature and amounts to significant levels at temperatures of human body. The results indicate that the effects under study may play an important role in triggering of thermoregulation of living organisms.

Термоэлектрические и термоэлектрокинетические явления в коллоидных системах, модельных биологическим жидкостям живых организмов

The paper presents the results of experimental measurements of thermoelectromotive force, thermoelectrokinetic EMF and conductivity coefficient in aqueous solutions, model in their properties and composition of human blood: medical ringer solution, serum albumin, ringer solution containing serum albumin. The influence of organic colloidal particles present in aqueous solutions of inorganic electrolytes on the value of their coefficient of thermoelectromotive force is analyzed. As follows from the results of the experiments, the coefficient of thermoelectromotive force of the studied liquids, based on the ringer solution, has a sharp dependence on temperature and acquires a large value in the temperature range in which the living human body functions. The obtained result indicates that the studied phenomena can play an important role in triggering the mechanisms of thermoregulation of living organisms.

Time and Mechanism of Nanoparticle Functionalization by Macromolecular Ligands during Pulsed Laser Ablation in Liquids.

Laser ablation of gold in liquids with nanosecond laser pulses in aqueous solutions of inorganic electrolytes and macromolecular ligands for gold nanoparticle size quenching is probed inside the laser-induced cavitation bubble by in situ X-ray multicontrast imaging with a Hartmann mask (XHI). It is found that (i) the in situ size quenching power of sodium chloride (NaCl) in comparison to the ablation in pure water can be observed by the scattering contrast from XHI already inside the cavitation bubble, while (ii) for polyvinylpyrrolidone (PVP) as a macromolecular model ligand an in situ size quenching cannot be observed. Complementary ex situ characterization confirms the overall size quenching ability of both additive types NaCl and PVP. The macromolecular ligand as well as its monomer N-vinylpyrrolidone (NVP) are mainly effective for growth quenching of larger nanoparticles on later time scales, leading to the conclusion of an alternative interaction mechanism with ablated nanoparticles compared to the electrolyte NaCl, probably outside of the cavitation bubble, in the surrounding liquid phase. While monomer and polymer have similar effects on the particle properties, with the polymer being slightly more efficient, only the polymer is effective against hydrodynamic aggregation.

Flotation of copper-bearing shale in solutions of inorganic salts and organic reagents

Flotation data on copper-bearing shale in aqueous solutions of inorganic electrolytes (NaCl, Na2SO4, KPF6, NH4Cl) and organic reagents (ethylamine, propylamine) as frothers were presented and discussed. The relationships between shale flotation, surface tension of aqueous solution and foam height during bubbling with air in the flotation system were presented. It has been found that flotation of shale in the presence of inorganic salts the yield was directly proportional to the surface tension of the aqueous solution of salt and inversely proportional to the height of the foam. On the other hand, for organic reagents solutions (short chain amines), a reverse effect has been observed in relation to the inorganic compounds studied, that is the yield of copper-bearing shale flotation and the foam height were inversely proportional to the surface tension of the amine solution.

Flotation of copper-bearing shale in solutions of inorganic salts and organic reagents

Flotation data on copper-bearing shale in aqueous solutions of inorganic electrolytes (NaCl, Na 2 SO 4 , KPF6, NH 4 Cl) and organic reagents (ethylamine, propylamine) as frothers were presented and discussed. The relationships between shale flotation, surface tension of aqueous solution and foam height during bubbling with air in the flotation system were presented. It has been found that flotation of shale in the presence of inorganic salts the yield was directly proportional to the surface tension of the aqueous solution of salt and inversely proportional to the height of the foam. On the other hand, for organic reagents solutions (short chain amines), a reverse effect has been observed in relation to the inorganic compounds studied, that is the yield of copper-bearing shale flotation and the foam height were inversely proportional to the surface tension of the amine solution.

Characteristics of PD-sensors based on hybrid perfluorinated membranes in aqueous solutions of inorganic electrolytes and lysine

The characteristics of PD-sensors based on MF-4SC perfluorosulfonic cation-exchange membranes, particularly those containing surface-functionalized silica nanoparticles, in HCl, NaCl, KCl, CaCl2, and lysine monohydrochloride solutions have been studied. It has been revealed that the degree of hydration of inorganic cations has a dominant effect on the magnitude of PD-sensor response in individual electrolyte solutions. It has been shown that the response and sensitivity of PD-sensors based on hybrid materials with respect to lysine cations increase with increasing concentration of amino groups grafted to SiO2. This feature is attributed to an increase in the counterion concentration in the film owing to a decrease in the water uptake and enhancement of the interaction between the counterions and the functional groups (sulfo groups of membrane, amino groups of dopant) in membrane.

Impact of interface approach velocity on bubble coalescence

We studied the coalescence of air bubbles in pure water and aqueous solutions of inorganic electrolytes and frothers by measuring the lifetimes of thin free aqueous films formed at a broad range of interface approach velocities with using a microfabricated film holder. For pure water, at ultra-low approach velocities the formed films were highly unstable, and the film lifetimes increased with increasing the approach speed, reaching a peak before decreasing at higher approach speeds. Similar trend was observed for the lifetimes of the films containing inorganic electrolytes and frothers of different types and concentrations. The results suggested that interface approach velocity might be an important factor affecting bubble coalescence in flotation.

ChemInform Abstract: Superselective Aqueous Inorganic Phases in Vapor-Phase Gas Chromatography

Chromatographic characteristcs of aqueous solutions of inorganic electrolytes, a new class of stationary liquid phases (SLP) for vapor-phase chromatography, are considered. The SLP are characterized by an unusually high selectivity to organic compounds of the R-X type (R is a hydrocarbon radical, X is a polar group,e.g., hydroxyl, carboxyl, and amine; for instance, light C1-C6 alcohols are eluted from the column with a water-containing phase in the following order: hexanol<pentanol<butanol<propanol<ethanol<methanol). The nature of the electrolyte used and its concentration in the water-containing SLP have a crucial influence on the column selectivity and the degree of separation of the compounds subjected to chromatography. This feature provides the possibility of controlling the column selectivity by changing the content of water vapor in the mobile phase.

Quantitative Theory of Surface Tension and Surface Potential of Aqueous Solutions of Electrolytes

The surface tension and surface potential of aqueous solutions of inorganic electrolytes are calculated. The new model includes image forces at liquid interfaces, ions of finite radii, the hydrophobic effect, and the Parsons−Zobel effect. For the first time, a good correlation between theory and experimental data both qualitatively and quantitatively is obtained for different inorganic salts over a wide range of concentrations.

Superselective aqueous inorganic phases in vapor-phase gas chromatography

Chromatographic characteristcs of aqueous solutions of inorganic electrolytes, a new class of stationary liquid phases (SLP) for vapor-phase chromatography, are considered. The SLP are characterized by an unusually high selectivity to organic compounds of the R-X type (R is a hydrocarbon radical, X is a polar group,e.g., hydroxyl, carboxyl, and amine; for instance, light C1-C6 alcohols are eluted from the column with a water-containing phase in the following order: hexanol<pentanol<butanol<propanol<ethanol<methanol). The nature of the electrolyte used and its concentration in the water-containing SLP have a crucial influence on the column selectivity and the degree of separation of the compounds subjected to chromatography. This feature provides the possibility of controlling the column selectivity by changing the content of water vapor in the mobile phase.

Flotation in inorganic electrolytes; the relationship between recover of hydrophobic particles, surface tension, bubble coalescence and gas solubility

Abstract The influence of a series of aqueous solutions of inorganic electrolytes on the flotation performance of graphite particles was determined. The results were related to the electrostatic interaction (as expressed in terms of the thickness of the electrostatic double layer) the surface tension and the solubility of gases in the electrolyte solutions. Overall, high flotation recoveries were attributed to an increase in the bubble-particle collision probability and possibly bubble entrainment floc flotation. This resulted from the higher concentration of smaller stable bubbles and also a reduction in the electrostatic interactions between particle and bubble.

Flotation of Inherently Hydrophobic Particles in Aqueous Solutions of Inorganic Electrolytes

The flotation of graphite particles in aqueous solutions of inorganic electrolytes was shown to depend on both the nature of the cation/anion pair and the range of the bubble/particle electrostatic interaction. For several electrolytes, as the reduction in the Debye length of the solution approached the decay length of the hydrophobic attraction, then flotation began to occur. Also using earlier reported data, it was possible to relate the flotation to surface tension/electrolyte concentration gradients and bubble coalescence behavior of the different electrolyte solutions. Higher flotation recoveries were attributed to an increased collision probability between the graphite particles, a higher concentration of small noncoalescing bubbles, and an increased stability of the froth. Furthermore, it has also been shown from previous studies that increasing electrolyte concentration causes a decrease in gas solubility. In fact, gas solubility has been shown to be dependent on the hydration entropy of the cation. This phenomenon was explained in terms of competitive utilization of water molecules in the hydration of cations and a consequent loss or gain in gas solubility. Overall, it was shown that a reduction in the electrostatic interactions between particle and bubble assisted flotation. However, in addition, an increase in flotation performance resulted from the inhibition of coalescence of bubbles, which is also linked with dissolved gas concentration gradients (structural differences at the air/solution interfacial region relative to the the bulk electrolyte solution).

Swelling equilibria of cationic polyelectrolyte gels in aqueous solutions of various electrolytes

Swelling experiments were carried out with three cationic polyelectrolyte gels of N-n-butyl-4-vinylpyridinium bromide (BPyBr), N-n-butyl- N, N-dimethyl-4-vinylanilinium bromide (BAnBr) and N-n-butyl- N, N-dimethyl-( N'-acryloyl-3-aminopropyl)ammonium bromide (BAPABr). The swelling equilibria of the gels were measured in aqueous solutions of inorganic electrolytes: HBr, NaBr, KBr, NaCl and NaI. The swelling ratios of the gels did not depend on the cationic species of the electrolytes examined but depended strongly on the anionic species. Volume phase transitions were not observed with the BPyBr and BAnBr gels in aqueous solutions of NaCl and NaBr whereas a phase transition was observed in an aqueous solution of NaI. The NaI concentration at which the phase transition occurred was raised with an increase in temperature. On the other hand, no discontinuous change was observed in the swelling equilibria of the BAPABr gel, even in the NaI aqueous solution. Comparison of the present results for the BAPABr gel with previous results for a polyelectrolyte gel verified the importance of hydrophobic interactions, which enhance the occurrence of volume phase transitions.

Electrical properties of the gold—aqueous solution interface

The electrokinetic properties of gold particles dispersed in aqueous inorganic electrolyte solutions have been studied using the technique of microelectrophoresis. Results obtained for dispersions formed from vacuum-evaporated metal indicate that electrical charge development at the “pristine” surface of gold in contact with aqueous solutions arises from the presence of a surface oxide layer. The influence of halide ions on the electrokinetic properties of these particles is consistent with metal—halide interactions involving both ligand exchange and specific anion adsorption. Evidence has been obtained which indicates that in the case of dispersions formed by citrate reduction of chloroauric acid, strongly adsorbed citrate ions modify the metal surface and inhibit interactions with halide species.

Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon

The salting constant ks of acetonitrile (AN) for inorganic electrolytes in water (NaCl, NaNO3, NaClO4, CsCl, CsNO3, Na2SO4, BaCl2, CuSO4, LaCl3, AgNO3) has been determined using a precise static vapour pressure method. A very strong dependence of ks on solute (AN) concentration was found down to very dilute AN concentrations (mAN < 0.3 mol kg–1) in the case of BaCl2, LaCl3, CuSO4 and AgNO3, indicating that Henry's law, and hence the true salting constant, could not be experimentally attained for AN in the presence of these electrolytes. Such a dependency was not observed with the other electrolytes; a cavity term (using the scaled-particle theory) and an interaction term (using a Lennard-Jones 6–12 potential) describe most parts of the true ks values. The small but systematic discrepancies between experimental and calculated salting constants for most polar solutes investigated with the present approach in aqueous inorganic electrolyte solutions can be accounted for by a preferential solvation effect of inorganic ions by water (in the case of the alcohols, tetrahydrofuran, acetone, acetonitrile); thus, permanent dipole–dipole forces between the polar solute and the water molecules do not necessarily have to be introduced in order to predict the salting effect of polar molecules by inorganic ions in water.

Scaled-particle theory and salting constant of tetrahydrofuran in various aqueous electrolyte solutions at 298.15 K

The vapour pressure change upon addition of electrolytes to dilute aqueous tetrahydrofuran (THF) solutions has been determined at 298.15 K. From these data the salting constants ks(Setchenov constant) have been calculated for THF in aqueous electrolyte solutions with: NaCl, NaNO3, NaClO4, NaBr, CsBr, CsNO3, AgNO3, Ni(NO3)2, NiCl2, CaCl2, BaCl2, Na2SO4, CdSO4, CuSO4, LaCl3, Me4NBr, Et4NBr, Pr4NBr, Bu4NBr, NaPh4B and Ph4AsCl. Using classical extra-thermodynamic assumptions single-ion ks values are calculated. It is shown, using the scaled-particle theory (SPT) that a Lennard-Jones 6–12 potential can describe the interaction of the THF molecule with all the inorganic cations. This may be considered as evidence that collisions occur between the THF molecule and the inorganic cations studied, although the ions should be considered as preferentially hydrated. Comparison of the behaviour of dilute THF and benzene aqueous inorganic electrolyte solutions suggests that under these conditions, THF behaves as a non-polar molecule. In the case of the interaction with organic ions, the THF molecule induces, unlike benzene, an additional repulsion term.

COAGULATION OF AQUEOUS POLYMER SOLUTIONS BY INORGANIC ELECTROLYTES

As a first step of explicating the spinning mechanism of viscose rayon, dehydration index of aqueous inorganic electrolyte solutions was studied. Sonic velocity in the solutions was measured by a ultrasonic interferometer and the amount of hydration was calculated according to Wada and coworkers. As a criterion of dehydration ability of electrolyte solutions, following formula was proposed.where s: dehydration index of electrolyte solution (%), v2: amount of hydration (cc/g solute), d0: density of solvent (g/cm3), andm: concentration of electrolyte solution (%).The values of s thus obtained were compared with the experimental results of coagulation of polyvinyl alcohol and methyl cellulose solutions. As for sulphates such as Na2SO4, Li2SO4, MgSO4, ZnSO4, CuSO4 and Al2 (SO4)3 and nitrates such as KNO3 and NH4NO3, it was found that the coagulation index obtained by dehydration index was nearly equal to the coagulation index obtained by coagulation experiments. Consequently s was considered to be adequate to use as a criterion of dehydrating power of electrolyte solutions. Using the dehydration index, coagulation of aqueous Na-cellulose xanthate solution by inorganic salts was investigated. By comparing the dehydration index of inorganic electrolyte solutions with the results of coagulation experiment of polyelectrolyte solution, following conclusions were obtained.The coagulation of aqueous Na-cellulose xanthate solution by inorganic salts is understood by three mechanisms.a) Dehydration is dominant.(salts of Na+, Li+ and Mg++)b) The interaction between the polyelectrolyte and inorganic ions is dominant.(salts of Zn++, Cu++)c) Intermediate between a) and b)(salts of K+ and NH+4)

Surface charge and adsorption properties of polyethylene in aqueous solutions of inorganic electrolytes

Adsorption of trace amounts of cations (Ba2−), molecules (Hg(OH)2) and colloids (Fe(OH)3) on polyethylene from aqueous solutions has been studied as a function of the concentration and composition of the electrolyte, pH and age of the solution. The results were analysed and compared with the effect of these factors on zeta potential of polyethylene. It has been concluded that the negative zeta potential indicates that cations can be adsorbed in the outer part of the surface double layer, but the degree of the adsorption is not simply proportional to the zeta potential. Macroconcentrations of electrolytes affect substantially the sorption capacity of polyethylene for cations. Adsorption of molecules and colloids on polyethylene has no direct relation to its zeta potential. The adsorption is mostly enhanced by the addition of an electrolyte, but higher concentrations of the electrolyte may suppress it again. The most probable explanation of the electrolyte effect is the change of the properties of the interface polyethylene-solution or the coagulation of colloids.

Effect of salts on the rate of mass transfer across a plane interface between a gas and mechanically agitated aqueous solutions of inorganic electrolytes

The mass transfer coefficient of physical absorption by a free surface into agitated liquid was measured. Oxygen and helium were being absorbed into water and solutions of strong inorganic electrolytes. It has been found that the mass transfer coefficient decreases with increasing salt concentration. This has been attributed to the surface film properties of the electrolyte solutions. Correlations for single-component liquids, suggested in the literature, are short of yielding an adequate description of the changes in mass transfer coefficient values provoked by the addition of salts. An adequate description has been obtained by including the effects of gravity and surface forces in the form of Weber and Froude numbers as well as the effect of electric forces expressed by the value of surface potential.

Surface charge and adsorption properties of polyethylene in aqueous solutions of inorganic electrolytes

The streaming potentials of several sorts of polyethylene were determined as a function of pH and composition of aqueous solutions and the electrokinetic (zeta) potentials were calculated. The results were compared with the electrokinetic properties of glass and polystyrene. It has been found that H+ and OH− ions are potential-determining on polyethylene. The surface of polyethylene is charged negatively above pH 2.5, probably due to dissociation of carboxyl groups, contained on polyethylene as a result of its oxidation during its polymerization and/or further processing. The zeta potentials depend in a rather complicated way on the concentration of various 1∶1 inorganic electrolytes. The probable interpretation of this dependence has been given and conclusion was derived about the absence of compact adhered layer of water molecules at the surface of polyethylene. The results of the present work may be of some importance for elucidating the adsorption properties of polyethylene.