Solubility Of Argon Research Articles

The solubility of argon in vitreous silica

A modified Seiverts method was used to measure inert gas solubility in fused silica. Using the original (average site) model equation, and a solubility site density of N s = 2.3 × 10 21/cm 3, helium solubility data gave a vibrational frequency for the helium atom of 4.6 × 10 12 s −1 and a binding energy of −2.02 kcal/mol. Using a vibrational frequency value of 1.5 × 10 12 s −1 for the argon atom, the argon solubility data gave a binding energy of −7.0 kcal/mol and a solubility site density of 9.8 × 10 19/cm 3. The density of accessible sites to argon atoms is reasonably consistent with a log-normal model of interstitial site structure.

Special features of the solubility of argon in solvents with a three-dimensional hydrogen bond framework

1. This is the first report of a gas solubility maximum in a nonaqueous electrolyte solution. The argon solubility maximum corresponds to a minimum for entropy losses due to the formation of cavities in the solvent. 2. The concept of a “limiting solvophobic effect temperature” was proposed.

Structural characteristics of aqueous solutions of tetraalkylammonium halides derived from argon solubility data

1. The solubility of argon in aqueous solutions of tetraalkylammonium halides has been measured at different concentrations in the temperature range 273–298°K. A maximum in argon solubility has been observed on the curves representing the solubility as function of concentration. 2. An anomalous shift of the maximum in the argon solubility with respect to the concentration of the salts has been observed, depending on the size of the alkyl groups entering into the composition of the tetraalkylammonium halides. 3. In all systems studied the maximum in argon solubility corresponds to a minimum in entropy losses, related to the formation of cavities in the solvent. The results obtained are interpreted on the basis of modern concepts of the structure of liquid solutions.

Photovoltaic measurement of bandgap narrowing in moderately doped silicon : Jesus A. Del Alama, Richard M. Swanson and Arto Lietoila. Solid-St. Electron.26 (5), 483 (1983)

Argon diffusivities and solubilities in single, gem-quality crystals of forsterite, enstatite, quartz and corundum were determined from experiments conducted between 0.5 and ~ 6000 bars Ar pressure and temperatures from 425 °C to 1200 °C. Polished single-crystal slabs and specimens with natural facets were placed in open containers and exposed to an argon atmosphere either in a pressure vessel or in a gas-flow tube furnace at near-atmospheric pressure. Argon atoms from the pressure medium diffused into the crystals to produce near-surface concentration gradients, which were directly profiled using Rutherford backscattering spectrometry. The following Arrhenius relations were obtained for Ar diffusion:The reported activation energies probably represent apparent activation energies that are a combination of the effects of lattice diffusion of Ar atoms with trapping in point-defect vacancies. There are no discernible differences in Ar diffusion in different crystallographic directions, and diffusivities do not vary as a function of the intrinsic oxygen fugacity of the experimental vessels.In addition to diffusivities, the uptake gradients also yielded lattice solubilities of argon, as represented by the concentrations at the mineral surfaces. There are small differences between the solubilities of forsterite, quartz and corundum, but all solubilities are high at ~ 2000 ppm (by mass). The Ar solubilities for the iron-bearing minerals enstatite and San Carlos olivine are much higher than for the other minerals. The mean value for enstatite is 30–60% higher than the iron-free minerals, owing, perhaps, to incorporation of Ar in point defects that are more abundant in enstatite due to oxidation of minor FeO. Argon solubilities are independent of Ar pressure at PAr > ~ 1 bar, but slightly lower at PAr ≈ 0.5–1 bar. This behavior suggests that all sites capable of accommodating Ar atoms are filled at Ar pressures of ~ 1 bar. In all cases, Ar appears to be compatible in the minerals investigated, although the degree of compatibility will depend upon assumptions concerning the minimum Ar fugacity required to fully populate the available vacancies. A series of validation experiments and surface-sensitive analyses were conducted to confirm that the near-surface regions of crystals used in the experiments were crystalline, unreacted and free of structural damage that could potentially influence diffusion and solubility results.

The solubility of noble gases in water and in NaCl brine

A direct-sampling, mass-spectrometric technique has been used to measure simultaneously the solubilities of He, Ne, Ar, Kr, and Xe in fresh water and NaCl brine (0 to 5.2 molar) from 0° to 65 °C, and at 1 atm total pressure of moist air. The argon solubility in the most concentrated brines is 4 to 7 times less than in fresh water at 65 °C and 0°C, respectively. The salt effect is parameterized using the Setschenow equation. ln [ β i o(T) β i(T) = MK i M(T) where M is NaCl moiarity, β i o ( T) and β i ( T) the Bunsen solubility coefficients for gas i in fresh water and brine, and K i M ( T) the empirical salting coefficient. Values of K i M ( T) are calculated using volumetric concentration units for noble gas and NaCl content and are independent of NaCl molarity. Below about 40°C, temperature coefficients of all K i M are negative. The value of K He M is a minimum at 40°C. K Ar M decreases from about 0.40 at 0°C to 0.28 at 65 °C. The absolute magnitudes of the differences in salting coefficients (relative to K Ar M ) decrease from 0° to 65°C. Over the range of conditions studied, all noble gases are salted out, and K He M ≲ K Ne M < K Ar M < K Kr M < K Xe M . From the solubility data, we calculated Δ G 0 tr , Δ S 0 tr , Δ H 0 tr and Δ C O p,tr for the transfer of noble gases from fresh water to 1 molar NaCl solutions. At low temperatures Δ S 0 tr , is positive, but decreases and becomes negative at temperatures ranging from about 25°C for He to 45°C for Xe. At low temperatures, the dissolved electrolyte apparently interferes with the formation of a cage of solvent molecules about the noble gas atom. At higher temperatures, the local environment of the gas atom in the brine appears to be slightly more ordered than in pure water, possibly reflecting the longer effective range of the ionic fields at higher temperature. The measured solubilities can be used to model noble gas partitioning in two-phase geothermal systems at low temperatures. The data can also be used to estimate the temperature and concentration dependence of the salt effect for other alkali halides. Extrapolation of the measured data is not possible due to the incompletely-characterized minima in the temperature dependence of the salting coefficients. The regularities in the data observed at low temperatures suggest relatively few high-temperature data will be required to model the behavior of noble gases in high-temperature geothermal brines.

Study of the influence of the structure of water on the solubility of argon in solutions of alkali metal halides in heavy and ordinary water

Study of the influence of the structure of water on the solubility of argon in solutions of alkali metal halides in heavy and ordinary water

A study of the characteristic structural features of water?propylene glycol mixtures by the argon solubility method

A study of the characteristic structural features of water?propylene glycol mixtures by the argon solubility method

Interaction of gases in ionic liquid. 2. The solubility of argon and nitrogen in molten lithium nitrate and potassium nitrate

Interaction of gases in ionic liquid. 2. The solubility of argon and nitrogen in molten lithium nitrate and potassium nitrate

Influence of history on the gas sorption, thermal, and mechanical properties of glassy polycarbonate

AbstractGlassy polycarbonate has been subjected to sub‐glass‐transition annealing and exposure to high‐pressure CO2. The subsequently measured solubilities of nitrogen, argon, and CO2 in these specimens were found to be decreased by the former and increased by the latter. Annealing decreases the enthalpy of polycarbonate and mechanically embrittles it, whereas subsequent exposure to CO2 erases these effects of annealing, can make the polymer even more ductile than the untreated material, and can apparently give it a higher enthalpy. Annealing densifies the glass, whereas the CO2 treatment dilates it. The gas sorption observations are in accord with the dual‐sorption model, and the effects of prior history are apparently the result of changes in the Langmuir capacity, which evidently is a sorption mechanism that exists as a result of the nonequilibrium nature, or excess volume, of the glassy state.

Study of the characteristic structural features of aqueous solutions of butyric acid at 15?50�C from data on the solubility of the noble gases and the velocity of ultrasonic waves

The solubility of helium, neon, and argon in butyric acid and its mixtures with water has been studied throughout the entire range of concentrations, and the velocity of ultrasonic waves and the adiabatic compressibility at t = 25~ have been determined. It has been found that the dependence of these properties on the composition of the mixed solvent and temperature is characterized hy the presence of extremal points. From these it has been concluded that the structure of water is stabilized by the addition of butyric acid at Nacid 0.05. From the results obtained it follows that the dissolution of the noble gases increases the strength of the structure of the solvent. These regular features are confirmed by the nature of the change in the thermodynamic characteristics of the dissolution of the noble gases in aqueous solutions of butyric acid with change in composition.

Gas diffusion in fluoro-polymers before and after irradiation

A study was made of diffusion and solubility of argon in polytrifluoroethylene and a copolymer of tetrafluoroethylene and vinylidene fluoride before and after irradiation (in a vacuum of 10 −5 torr) with various doses of 60Co γ-radiation. Fluoropolymer films were prepared from solutions with subsequent removal of solvent. Diffusion was measured manometrically. Temperature dependences of permeability P, diffusion D and solubility of argon in fluoro-polymers σ, were measured. It was established that the fluoro-polymers studied are similar to PVC as regards activation energy of diffusion, enthalpy and entropy of solution of gases and D 0 values. Irradiation of films produces an extremal solubility coefficient and minimum P and D values on the dose curve in the region of 200–300 Mrad, which is evidence of competing processes of structure formation, degradation, amorphization and unsaturation taking place in fluoro-polymers.

Solubility of nitrogen, argon, methane, and ethane in ethylene oxide

Solubility of nitrogen, argon, methane, and ethane in ethylene oxide

Solubility of argon in aqueous solutions of diethylene glycol at 20?40�C

Solubility of argon in aqueous solutions of diethylene glycol at 20?40�C

Solubility of carbon dioxide, nitrogen, and argon in molten zinc chloride

A volumetric method for measuring the solubility of gases in molten salts has been elaborated, and solubilities of CO 2 over the range 709 to 778 K, N 2 at 720 K, and Ar at 720 K have been determined. The results are discussed in terms of Blander's model.

Solubility of argon in water + alcohol systems

The solubility of argon has been measured in water + ethanol, and in water + t-butanol mixtures, over the whole range of their concentrations and at several temperatures between 4°C and 62°C. The thermodynamic functions Δtext-decoration:overlineH⊖ and Δtext-decoration:overlineS⊖ were calculated for the solution process, and used to elucidate the effects of these alcohols on the structure of water. The effect of methanol is also compared, using data from the literature. These effects are related to the size of the alkyl group in the alcohol molecule. From the results a quantitative estimate is made of the relative amounts of hydrogen-bonded structures in water over the temperature range studied.

The solubility of argon in aqueous solutions of a complex-ion electrolyte

From measurements of the solubility of argon in aqueous solutions of the complexion electrolyte t-[Co(en)2NCSCl]Br at 25°C, the Setschenow parameter for this system is found to be +0.336. Using the scaled-particle theory of the salt effect with this value ofk5 and the Waddington crystal radius of the Br− ion, 1.98 A, the radius of the complex cation is calculated to be 3.71 A. This value is in reasonably good agreement with that estimated from scale models of the t-[Co(en)2-NCSCl]+ cation, about 3.9 A. It is somewhat larger than the radius calculated from various semiempirical equations relating the molal volume of an ion at infinite dilution to its radius; values of r obtained in this manner range from 3.32 to 3.66 A.

Solubility of helium and argon in liquid sodium

Solubility of helium and argon in liquid sodium

The effect of salinity on the solubility of argon in seawater

New argon solubility measurements, made by two independent methods, confirm the use of the Setchénow relation in representing the salting-out of argon in seawater. No substantiation was found for the unusual salinity dependence implied by the argon solubility data of Murray and Riley (1970).

Solubility of the noble gases in liquid sodium

A novel method has been employed to measure the solubility of argon and helium in liquid sodium as a function of gas partial pressure, temperature, and purity of the sodium. The values obtained can be correlated well with the experimental results available for the few other liquid metal-noble gas systems investigated. Theoretical calculations with an improved hard-sphere model also confirm the experimental results derived here. This allows a prediction also of the solubility of xenon in sodium. Some safety problems closely connected with the solubility of noble gases in the reactor coolant sodium are dealt with by the example of the German 300 MWe liquid metal fast breeder reactor (SNR).

The solubility of nitrogen, oxygen and argon in water and seawater

Recent precise data on the solubilities of nitrogen, oxygen and argon in distilled water and seawater are fitted to thermodynamically consistent equations by the method of least squares. The temperature dependence of the Bunsen solubility coefficient is treated using the integrated van't Hoff equation. It is shown that the Setchénow relation gives an adequate representation of the salting-out effect. Equations expressing the solubilities of these gases, as a function of temperature and salinity, in units of the Bunsen coefficient, ml/l., and ml/kg are given along with solubility tables in each of these units.