Measurement and modeling of oxidation rate of hydrogen isotopic gases by soil

Measurement and Modeling of the Oxidation Rate of Hydrogen Isotopic Gases by Soil

“…Model Description where v ref is the reference oxidation rate, and f s ð; K m Þ, f w ðÞ, f T ðTÞ, and f z ðzÞ respectively express the dependency of oxidation rate on substrate concentration, soil water content, soil temperature and soil depth. There was no significant difference in the magnitude of the oxidation rate obtained by the present study and reported by Ota et al (2007). Therefore, coefficients of the equation used by the model were determined by summarizing the measurement results of the oxidation rate of andosol obtained by the two studies, and listed in …”

“…Michaelis constant K m increased exponentially with increasing soil temperature, and K m of H 2 were generally larger than those of D 2 . Dependencies of the oxidation rate on each controlling factor were well expressed by the empirical formulae proposed by Ota et al (2007) regardless of the soil type. Difference between the modeled oxidation rate and measurement one for three types of soil and the seasonal variation in the oxidation rate were generally within a factor of 2.…”

“…Here, one can model r atm and r soil with knowledge about turbulent transport of HT in the atmosphere and diffusion of HT in soil. Ota et al (2007) developed an empirical model of the HT oxidation, which was proposed by experimental results on the oxidation rate of D 2 simulating HT. Since the formulae adopted by the model were based on the experimental results on the oxidation rate of a certain type of soil (andosol), it has been necessary to verify whether the model can be generalized to the soil other than andosol, especially to soils of farm lands and paddy fields, considering ingestion dose from OBT.…”

“…Significant difference between the oxidation rate of H 2 and D 2 was not observed, while the oxidation rates of H 2 were generally larger than those of D 2 at ¼ 480 ppm. 1) Although the reasons for this are not clear, we proposed following hypotheses. An oxidation reaction includes two elemental processes, both of which can be the rate-determining process of the oxidation reaction: diffusion of H 2 or D 2 from soil air to soil microorganisms, and oxidation of H 2 or D 2 by them.…”