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

Measurements of oxidation rate of hydrogen isotopic gases by soil were made to model HT oxidation rate by soil. Soil was sampled at a cultivated farmland and laboratory measurements of the oxidation rate of H2 and D2 gases simulating HT gas were carried out under controlled conditions of soil. The oxidation rate increased with increase of H2 or D2 concentration in air and nearly saturated at high concentration. The oxidation rate was low under extremely dry and wet soil conditions and was the highest at soil water content of 8–14 w/w%. The oxidation rate increased exponentially with increasing soil temperature and was the highest at 46 °C. Michaelis constant Km increased exponentially with increasing soil temperature. Oxidation rate of H2 was generally higher than that of D2, while Km of H2 was generally lower than that of D2. From these results, oxidation rate of HT was modeled as a product of the functions that represent dependency on each soil factor.