n-Heptane adsorption and desorption on porous silica observed by positron annihilation lifetime spectroscopy

2012 ◽  
Vol 154 ◽  
pp. 142-147 ◽  
Author(s):  
Radosław Zaleski ◽  
Waldemar Dolecki ◽  
Agnieszka Kierys ◽  
Jacek Goworek
2012 ◽  
Vol 733 ◽  
pp. 207-211 ◽  
Author(s):  
Radosław Zaleski ◽  
Waldemar Dolecki ◽  
Jacek Goworek

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.


2001 ◽  
Vol 89 (9) ◽  
pp. 5138-5144 ◽  
Author(s):  
Jia-Ning Sun ◽  
David W. Gidley ◽  
Terry L. Dull ◽  
William E. Frieze ◽  
Albert F. Yee ◽  
...  

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