The diffusion coefficients of ten slightly soluble gases in water at 10–60°C

Abstract

Diffusion coefficients for dissolved hydrogen, oxygen, nitrogen, air, helium, argon, methane, ethane proprane and n-butane have been measured in water at 10°, 20°, 30°, 40°, 50° and 60°C by following the rate of collapse of small bubbles in gas-free water, the results being compared wherever possible with corresponding diffusivities published in the literature. The temperature dependence of the diffusion coefficients is expressed in terms of an Arrhenius-type exponential relationship, the frequency factor and activation energy for dissolved gas diffusion in water being interpreted in terms of the hole mechanism of activated self diffusion originally proposed by Eyring. The solute gas diffusivities in water are also compared with those predicted theoretically from solvent viscosity by the relationships of Einstein, Eyring, Longuet-Higgins and Pople, Ree, Ree and Eyring, and Houghton, the purpose being to find a physical explanation for the observed variation of diffusion coefficient with solute molecule size.