Dissolution Of Gases Research Articles

Temperature parameters of the gas permeability of polymers

The paper relates to statistical treatment of published data on diffusion coefficients, and on the solubility and permeability of inert (and some polyatomic) gases in various polymers at elevated temperatures. The found correlation dependences relate temperature parameters of the gas permeability of polymers to the size of gas molecules and to their force constants of the Lennard-Jones potentials. It is shown that activation energies of diffusion and permeability, and heats of dissolution of gases in polymers may be calculated.

Flow-microcalorimetric techniques for solution of slightly soluble gases. Enthalpy of solution of oxygen in water at 298.15 K

Two flow-microcalorimeter vessels have been designed for the determination of enthalpy of solution of slightly soluble gases. In one approach, constant flows of gas and solvent are brought together to form a steady-state system of gas dissolution. In the second method, a gas is added into the solvent flow. Both methods were shown to give precise results for the dissolution of rare gases and hydrocarbons in water. The enthalpy of solution of oxygen in water at 298.15 K was determined to be ΔH = − (12.06±0.04) kJ·mol −1.

Permeation, diffusion and dissolution of hydrogen isotopes, methane and inert gases through/in a tetrafluoroethylene film

Tetrafluoroethylene (TFE) is widely used for conventional tritium handling systems such as vacuum seals, tubing and so on. We measured the permeation of the three hydrogen isotopes, methane and the inert gases through a TFE film at room temperature by means of the time-lag method in order to establish the physicochemical properties which determine the solubility and diffusivity of those gases. It was found that the diffusion constant of the inert gases changed exponentially with the heat of vaporization and the solubility was an exponential function of the Lennard-Jones force constant of the gases. On the other hand, hydrogen isotopes and methane deviated from these relations. It is concluded that chemical interactions between the solute and the solvent play an important role for the dissolution and the diffusion of these gases in TFE.

Field measurements of volcanic gases. Vulcano Island (Italy), Kilauea (Hawaii, U.S.A.), Merapi (Java, Indonesia)

A field gas chromatograph, built in 1978, was used in the field to directly analyse volcanic gases before water vapor condensation. Tested in Vulcano (Italy), Kilauea (Hawaii) and Merapi (Indonesia), this field measurement technique provides the actual composition of the volcanic gas mixture. The technique avoids the depletion of sulfur gases and the dissolution of the acid gases in the condensed water during the cooling. Thus the mixture of H2S and SO2 in fumarolic and high temperature gases (up to 819°C) in equilibrium at the emission temperature was examined.

The Standard Free Energies of Dissolution of Phosphorus Gases in Liquid Iron

The vapor pressures of phosphorus gases, P and P2, above Fe-P alloys have been determined by a newly developed experimental method. In this experimental method, phosphorus in the deposit film obtained by the Knudsen effusion method with collection technique was determined by a secondary ion mass spectrometer. The vapor pressures of P and P2 have been obtained from these determined values and the ratio of the ion currents of P+ to those of P+2 which had been obtained by the ordinary Knudsen cell-mass spectrometer combination. The standard free energy changes of the reactions for liquid Fe-P alloy system were calculated from these vapor pressures, and the following values have been obtained.P(g)=P(wt%)ΔG°=-95.3+1.55×10-2T(±2.2)(kcal/mol)1/2P2(g)=P(wt%)ΔG°=-37.7+0.13×10-2T(±1.1)(kcal/mol)P(g)=1/2P2(g)ΔG°=-57.6+1.42×10-2T(±1.1)(kcal/mol)(1-3wt% P, 1590-1650°C)

Dissolution of the primordial rare gases into the molten Earth's material

We have shown in a previous paper that, if the primordial solar nebula existed when the Earth was formed, the Earth was once surrounded by a dense and massive primordial atmosphere, whose temperature and pressure were about 4000 K and 900 atm, respectively, at the bottom. We suppose that this hydrogen-rich atmosphere escaped from the Earth after the solar nebula itself disappeared, both phenomena probably being due to the effect of strong solar wind and radiation. Using the results of our previous and new calculations on the structure of the primordial atmosphere, we have investigated the amount of dissolution of the rare gases, which were contained in the primordial atmosphere, into the molten Earth's material. The amount of the dissolved rare gases is found to be strongly dependent on the grain opacity of the atmosphere, i.e., on the amount of fine grains. However, their isotopic ratios and relative abundance are independent of the opacity and approximately equal to those in the primordial solar nebula, that is, to the present solar values. Especially, the dissolved neon is expected to have remained in the present mantle. Therefore, if a considerable amount of neon with nearly the solar isotopic ratio is discovered in present mantle material, this offers direct evidence for the proposition that the proto-Earth was once surrounded by the primordial atmosphere.

Wetting and impregnation of porous metal diaphragms

The wetting and impregnation of porous metal diaphragms such as those investigated in this work occur almost instantaneously when their surfaces are hydrophilic, but are unsatisfactory (are hindered by air) when their surfaces are partially hydrophobized. When a partially hydrophobized diaphragm and a liquid react with each other, full wetting is obtained, brough about by the processes of dissolution and diffusion of gases adsorbed inside pores on organic contaminants. A number of methods are proposed for improving the wetting and impregnation of partially hydrophobized diaphragms.

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.

Combined use of calorimetric and adsorption kinetic methods for the study of the mechanisms of catalytic processes

Consideration is given to the main results obtained in studies based on calorimetric methods at high temperatures (above room temperature) of the following aspects of the mechanisms of catalytic and sorption processes on powder catalysts: 1) relation between chemisorption and dissolution of gases in the subsurface layers of solids; 2) influence of surface-adsorbed substance on the adsorption of another substance from the gas phase; 3) nature of intermediate species formed during catalytic processes on the catalyst surface. Results are presented of the application of calorimetric methods to measuring the enthalpy change of polymerization in a “dry” system: gaseous monomer — solid catalyst — solid polymer, and to investigating the mechanisms of such processes. Anomalous solubility of gases in the subsurface layers of solids has been shown to be significant for the mechanism of nucleation during phase transitions in solids.

Adsorption and dissolution of gases during the milling of solids

1. BET methods and measurement of H2 chemisorption have been combined to determine the rate of new surface formation in the milling of quartz, corundum, silicon, germanium dioxide, molybdenum disulfide, and boron nitride. The second of these two methods can be used to determine the rate of new surface formation in the latter stages of the milling process where the BET method is no longer applicable because of particle aggregation. The work required for the formation of unit new surface area has been estimated. 2. Adsorptional methods have been used to detect and study the disorganization of the pre-surface layer structure and the effect of this factor, first on the dissolution of argon during solid body milling (silicon, quartz, GeO2) and then on the low-temperature sintering of materials such as MoS2.

Laboratory Studies Related to Artificial Recharge: ABSTRACT

Artificial groundwater recharge, by any method, is subject to limitations caused by some mechanism degrading the hydraulic conductivity of the porous media through which the recharge water is being infiltered or injected. Reduction of hydraulic conductivity may be caused by suspended solids, bacterial growth, chemical reactions of dissolved solids with the porous media or End_Page 1605------------------------------ existing native water, and air entrainment or dissolution of gases in interstices of the porous medium. A comprehensive study of factors affecting artificial groundwater recharge should include laboratory determinations of the relation of the various causes of hydraulic-conductivity reduction. Problems pertaining to the effect of water quality in relation to the lithologic environment of a recharge system also should be studied in the laboratory. A laboratory facility has been designed and equipped to provide means of testing flow through porous media columns. Any quality of recharge water from distilled water to activated sludge, can be constituted in quantities providing for indefinite term tests. Flow can be through repacked or field cores under constant flow or constant pressure. A flow-test data acquisition and computation system provides punched tape data storage and real time computation and plotting of intrinsic permeability changes with column depth and time. Water quality data are taken during the test, and characteristics of the porous media and suspended solids are determined. Accumulation of material in porous media interstices is visually observed with scanning electron microscopy. The data are analyzed to relate the physical, biologic, and chemical effects in the porous media flow system with the objective of obtaining data that can be transferred to field situations and thus develop more economical artificial-recharge systems. End_of_Article - Last_Page 1606------------

Dissolution of Gases in Vacuum Pump Oils

The solubilities of gases in various vacuum pump oils, such as Apiezon-C, Myvane, Octoil-S, Lion-A and Silicon (Heraeus- for ultra high vacuum), have been measured by the gas dissolution method between 20° and 150°C in the pressure range of 10 to 760 Torr. The dependence of solubility on temperature and pressure is given by L=kpn e- Q/RT. When air dissolves in oils, n is nearly equal to unity, but for other gases (H2, O2, N2, Ar) it shows various value from 0. 6 to 1. The temperature coefficients of these solubilities are all positive and heat of dissolution in synthetic oil is lower than in fractional, distilled mineral oil.

溶在瓦斯が湖水の密度に及ぼす影響

1) The changes of the densities of the waters from Lake Takasukanuma, which were caused by the dissolution of gases, have been calculated from the data of gas-analysis of the waters (Table 1) and the ANGSTROM'S coefficients of dilatation by absorption (Table 2), using HORIITPI's equation of density-change by absorption.2) The results show that, a) Except carbon dioxide, all kinds of dissolved gases are distributed in such a way that deeper lying waters tend to become lighter than upper lying ones. So the total decrease of density due to the dissolved gases and the gradient of its vertical change become larger as it goes deeper, while they attain their maximum in October 20th and become smaller as time advances.b) Parallelism is evident when we compare these results with the data of the measurement of the densities of waters, which were reported in my previous paper (1).3) Thus the decrease of density in the deepest water reported is explained partly by the dissolution of gases. But, as the amount of decrease due to the dissolved gases does not exceed 10% of the total decrease, the full explanation is hoped to be obtained along some other lines. Studies are being continued further along them.

III. The heat of dissolution of gases in liquids

III. <i>The heat of dissolution of gases in liquids</i>