Automated apparatus for gas solubility measurements

Dedicated to Professor J. Simões Redinha on the occasion of his 80th birthday
https://doi.org/10.1016/j.jct.2007.05.013Get rights and content

Abstract

An automated apparatus based on the Ben-Naim–Baer and Tominaga et al. designs [A. Ben-Naim, S. Baer, Trans. Faraday Soc. 59 (1963) 2735–2738; T. Tominaga, R. Battino, H.K. Gorowara, R.D. Dixon, J. Chem. Eng. Data 31 (1986) 175–180] has been implemented for measurements of gas solubilities in liquids under atmospheric pressure and room temperatures. The uncertainty in the measurement of gas solubilities was estimated from the uncertainties in the directly measured quantities using the error propagation law. The accuracy of the experimental method was checked by measuring the solubility of carbon dioxide and nitrous oxide in water in the range T = (290 to 303) K, being found to be 0.6%. A precision of the same order of magnitude was achieved.

Introduction

Ben-Naim and Baer have designed a volumetric gas solubility apparatus for slightly soluble gases in 1963 [1], which is considered a reference till nowadays. It is based on a direct reading of the change in volume of the gas during dissolution at constant pressure. A number of variations have been developed. One of these is the Tominaga et al. improved version [2] used in Battino’s laboratory, which combined easy handling with automated data retrieval and was totally mercury-free.

In this work, we present a new design for solubility measurements around room temperature and atmospheric pressure that incorporates the best features of both apparatuses.

Section snippets

Chemicals

Carbon dioxide and nitrous oxide were both Matheson products, Belgium, with a stated mole fraction purity of 0.995. The water (water G Chromasov) was obtained from Riedel and Häen, Germany.

Apparatus and solubility measurement

The experimental apparatus for solubility measurements is represented in figure 1. The principle of the method is to bring a measured amount of liquid into contact with a known volume of gas at a given temperature and pressure. After the equilibrium has been attained the change in the gas volume yields the

Calculations

In the following text we use the subscript 1 to identify the solvent (water) and 2 for the solute (gas). In this work, the experimentally accessible quantities are the displaced volume in gas burette due to the gas dissolution, ΔV, the mass of solution, ms, and the equilibrium pressure and temperature, P and T, respectively.

The amount of dissolved gas, n2 (in moles), can be obtained from ΔV through the equation,PVmixG/(RT)=1+BmixRT/P,where VmixG represents the molar volume in the vapour phase

Conclusions

A new automated apparatus for G/L solubility measurements was implemented which embodies the best features of two reference literature devices. Its performance was tested in the temperature range from 290 K to 303 K with high soluble gases, CO2 and N2O, in water. An accuracy better than 0.6% and a moderate precision of 0.5% were achieved.

In future work, the solubility of slightly soluble gases will be determined and we will extend the measurements to lower temperatures using an appropriate

Acknowledgements

This work was carried out under Research Project POCTI/EQU 44056/2002 financed by FCT – Fundação para a Ciência e Tecnologia (Portugal) and FEDER.

We thank Professor Alan E. Mather, from the University of Alberta, who kindly sent us the paper of C. Bohr.

References (15)

  • C.N. Murray et al.

    Deep-Sea Res.

    (1971)
  • A. Ben-Naim et al.

    Trans. Faraday Soc.

    (1963)
  • T. Tominaga et al.

    J. Chem. Eng. Data

    (1986)
  • H.L. Clever et al.
  • R. Battino et al.

    Anal. Chem.

    (1971)
  • P.G.T. Fogg et al.

    Solubilities of Gases in Liquids

    (1991)
  • E.H. Dymond et al.

    The Virial Coefficients of Pure Gases and Mixtures

    (1980)
There are more references available in the full text version of this article.

Cited by (19)

  • Solubility of H<inf>2</inf>S in ammonium-based ionic liquids

    2021, Journal of Chemical Thermodynamics
    Citation Excerpt :

    The experimental technique used in this work is based on a volumetric method. The apparatus used for the determination of solubility was described in detail elsewhere [24]. This procedure has shown to be highly accurate and precise in the past for various gases and solvents, making it a preferable choice [25,26].

  • Measurements and correlations of solubility of N<inf>2</inf>O in and density, viscosity of partially CO<inf>2</inf> loaded water-lean amino acid salts

    2018, Journal of Chemical Thermodynamics
    Citation Excerpt :

    It can be observed that the measured data match well with the reference data and the average absolute deviation (AAD, %) are within 0.13 for density and 1.82 for viscosity, respectively. To validate the solubility method in this work, the solubility of N2O in water at the investigated temperature range was measured in the VLE apparatus and compared with the most cited and recent data in open literature [38–44], presented in Table 3. Density data of water were obtained from the literature [45], and density data of EG and aqueous 95 mass% EG were measured in this work at the pressure of 101.3 ± 0.5 kPa.

View all citing articles on Scopus
View full text