In Situ Monitoring of Adsorption and Desorption of n-Heptane on Porous Silica by Positron Annihilation Lifetime Spectroscopy

Radosław Zaleski; Waldemar Dolecki; Jacek Goworek

doi:10.4028/www.scientific.net/MSF.733.207

Paper Titles

On the Relationship of the Relative Intensity I₃ and a Cavity Number as Obtained from Computer Simulations
p.183

Argon Plasma Decomposition of Porogen in Mesoporous Silica Films Studied by Positron Annihilation
p.193

o-Ps Lifetimes in Iron Containing Micro- and Mesoporous Media
p.197

Study of the Behavior of Positronium Annihilation in Porous Silicon
p.203

In Situ Monitoring of Adsorption and Desorption of n-Heptane on Porous Silica by Positron Annihilation Lifetime Spectroscopy
p.207

Positron and Positronium Annihilation as Probes to Identify Cation Substitution Effects in CoCr_xFe_2-xO₄
p.215

Ni-Substitution Induced Inversion in ZnFe₂O₄ Seen by Positron Annihilation
p.219

Positron Lifetime at Deep Donors of Radiation Origin in Proton - Irradiated FZ-Silicon Single Crystals
p.224

Hydrogen Interaction with Defects in ZnO
p.228

HomeMaterials Science ForumMaterials Science Forum Vol. 733In Situ Monitoring of Adsorption and Desorption of...

In Situ Monitoring of Adsorption and Desorption of n-Heptane on Porous Silica by Positron Annihilation Lifetime Spectroscopy

Abstract:

Positron annihilation lifetime spectroscopy study of n-heptane adsorption and desorption on silica gel Si-60 gives insight into a free volume evolution during those processes. Analysis of the lifetime distribution allows to ascribe particular ortho-positronium components to silica walls, mesopores and n-heptane. Hysteresis loop of the intensities of the mesopore and n-heptane related components similar to classic adsorption/desorption isotherms is observed. Transition from an adsorbate multilayer structure to liquid when pores become completely filled, manifests itself as an intensity change. Kinetics of desorption and adsorption studies allows to determine the time of reaching the equilibrium by the Si 60–n-heptane system at various pressures.