6533b7d9fe1ef96bd126be61

RESEARCH PRODUCT

Coadsorption of hydrogen and deuterium on zeolites at cryogenic temperatures : influence of the sorbent’s properties on selectivity

subject

description

The adsorption of hydrogen and deuterium (single gases and mixtures) was studied on a series of zeolites with varied parameters (Si/Al ratio, nature of the charge-compensating cation, pore geometry and diameter of pore aperture). Thermodynamic adsorption selectivities towards deuterium with respect to hydrogen were measured in a large pressure range (0.1 – 1000 hPa) and for several temperatures (45 – 100 K). The adsorption selectivity was assessed using direct coadsorption measurements performed by manometry coupled with mass spectrometry. For all studied zeolites and experimental conditions, the coadsorption process is selective towards deuterium, in agreement with the literature. However, the adsorption selectivity depends on the loading, the sorbent’s properties and the temperature. We have found that the coadsorption kinetics strongly influences the adsorption selectivity, especially at high loading. This work gives the guidelines for the choice of the formulation of materials and the optimal operating conditions for having an efficient separation of hydrogen isotopes using zeolite-based adsorbents.