On the adsorption and diffusion of water in BaX zeolite

Hervé Jobic (1) , Alain Méthivier (2) , Tilo Seydel (3)

1 IRC - Institut de recherches sur la catalyse
2 IFPEN - IFP Energies nouvelles
3 ILL - Institut Laue-Langevin

Quasi-elastic neutron scattering (QENS) has been used to study water adsorbed at different concentrations in BaX zeolite. It is found that, the lower the water content, the higher the temperature which is required to reach adsorption equilibrium. For a loading of 15 molecules per supercage, an evolution of the QENS intensity with time is observed at 440 K which suggests that the sample was not in equilibrium; for a loading of 10 molecules per supercage, this happens at 520 K. Even at the highest studied temperature, 520 K, the diffusion coefficient of water in the equilibrated samples is lower than 10–12 m2 s–1. This is much lower than in NaCaA zeolites, manifesting the very large interaction between water and the Ba cations.

Mots clés: Adsorption; Diffusion; Water; Zeolite; BaX; QENS

Domaines: Catalyse

Hervé Jobic, Alain Méthivier, Tilo Seydel. On the adsorption and diffusion of water in BaX zeolite. Comptes Rendus. Chimie, 2005, 8, pp.411-417. ⟨10.1016/j.crci.2004.09.012⟩. ⟨hal-00013516⟩