Thermodynamic study of water confinement in hydrophobic zeolites by Monte Carlo simulations

Alain H. Fuchs (1) , Fabien Cailliez (2) , Boutin Anne (3) , Isabelle Demachy (3)

1 Chemistry
2 ENSCP - Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL
3 UP11 - Université Paris-Sud - Paris 11

We report a Grand Canonical Monte Carlo simulation study of water condensation in 4 different hydrophobic, all-silica, zeolites. In all cases, water condensation takes place above the saturation vapour pressure through a first-order like phase transition, with a hysteresis loop. This is at odds with the common belief that conventional phase transitions cannot take place in microporous solids such as zeolites. Forced fluid intrusion experiments, have long been interpreted in terms of irreversibilities. What we show here is that the most important features of this process can be understood in terms of equilibrium thermodynamics considerations. Finally, a strong depletion of confined water is predicted in these nanoporous solids.

Mots clés: Physical Sciences

Alain H. Fuchs, Fabien Cailliez, Boutin Anne, Isabelle Demachy. Thermodynamic study of water confinement in hydrophobic zeolites by Monte Carlo simulations. Molecular Simulation, 2009, 35 (01-02), pp.24-30. ⟨10.1080/08927020802398900⟩. ⟨hal-00515055⟩