Solubility of hydrogen in water, sea water, and sodium chloride solutions

Abstract

Bunsen solubility coefficients for hydrogen in distilled water, in NaCl solutions at two concentrations, and in seawater at three salinities were determined with an estimated accuracy of 0.5%. A new data reduction method. utilizing the least-squares technique, was developed to fit the experimental data to an equation established by Weiss. A table of Bunsen solubility coefficients covering the temperature range -2' to 30°C and the salinity range 0-40 parts per thousand was calculated from the fitted equation. Solubility values for distilled water were in agreement with composite values of several workers reported by Linke. Solubility coefficients for NaCl solutions were compared with previous measurements and with solubility coefficients for seawater.Recent measurements of dissolved hydrogen in surface seawater (7, 72) have indicated an apparent excess of this gas with respect to atmospheric concentrations. Proper interpretation of such information requires accurate saturation values for dissolved hydrogen in seawater. This paper reports the measurement of Bunsen solubility coefficients for hydrogen in distilled water, in NaCl solutions at two concentrations, and in seawater at three salinities.Hydrogen solubilities in distilled water have been reported previously by several workers, but there are considerable differences among their results (7, 6, 9. 73).Generally accepted values are those of Linke ( 5 ) who averaged values from several workers. Solubilities in seawater have not been reported previously. Measurements have. however, been made in NaCl solutions by several investigators, most recently by Morrison and Billett (6).Both graphical and numerical methods have been used previously to reduce gas solubility data with respect to temperature and salinity. Douglas (3) used strictly graphical methods to fit his data for argon and nitrogen. Morrison and Billett (6) used a modified form of Van't Hoff's law to describe their data. Recently, Weiss (70) has established a thermodynamically consistent equation describing solubility in terms of temperature and salinity which he fit to solubility data by a stepwise method involving four separate least-squares fits. In the present work a data reduction method was developed to fit the entire set of solubilities in a single step to Weiss' equation by the least-squares technique. ExperimentalResearch grade hydrogen gas (Linde Specialty Gas, 99.9995% purity) was used for all measurements. Seawater was filtered through 0.45-1.rm Millipore filter membranes, poisoned with HgC12 (1 mg/l.), and stored in the dark. The seawater was then boiled or diluted to obtain desired salinities. Salinities were determined with a Beckman Induction Salinometer having an accuracy of f0.003 parts per thousand. Glass distilled water was used for distilled water measurements. The thermometer used in this work was calibrated against NBS standard ihermometers.' To whom correspondence should be addressed Seawater and distilled water were degassed by the vacuum extraction method developed by Douglas (3)...

Methane-Producing Microbial Community in a Coal Bed of the Illinois Basin

“…Measurements on replicate samples generally have a precision of about Ϯ1 ppm. Measured gas-phase partial pressure values were converted to pore water concentration by use of solubility constants corrected for temperature and salinity (10).…”

“…Calculations of Q involved activity corrections based on the average in situ salinity (3.11 g/liter) determined at pH 8 and an acetate concentration of 4.3 ϫ 10 Ϫ6 M. The ionic strength was 0.054 M, and the resulting activity coefficient ␥ of a single charged species (Davies equation) was 0.773. The molalities of aqueous-phase H 2 (H 2,aq ) and CH 4,aq were calculated using measured pH 2 and pCH 4 in coal gas and the appropriate Bunsen solubility coefficient, dependent on temperature and salinity (10). The activity coefficient of gaseous species was assumed to be 1; thus, their activities were equivalent to their molalities.…”

Thermodynamics of H2-consuming and H2-producing metabolic reactions in diverse methanogenic environments under in situ conditions

“…CH 4 was measured by a flame ionization detector with a detection limit of 1 /~M dissolved CH 4. Partial pressures were calculated from the dissolved gas concentrations by using Bunsen solubility coefficients for the in situ temperatures [16,17].…”

Acetogenesis from CO2 in an anoxic marine sediment

“…The vial was quickly sealed and shaken, retarding biological activity and partitioning the pore-water pool of hydrogen between the sediment and headspace. The partial pressure of H 2 in the headspace gas was determined in the same fashion as for the headspace equilibration methodology (Hoehler et al 1994) and was used to calculate the H 2 concentration in the pore water (using Crozier and Yamamoto 1974). The precision of this method (Ϯ30% among replicate samples) is not as good as with the headspace equilibration technique (Ϯ5%).…”