On the hysteresis of argon adsorption in a uniform closed end slit pore

Fan, Chunyan, Do, D. D. and Nicholson, D. (2013) On the hysteresis of argon adsorption in a uniform closed end slit pore. Journal of Colloid and Interface Science, 405 201-210. doi:10.1016/j.jcis.2013.04.052

Author Fan, Chunyan
Do, D. D.
Nicholson, D.
Title On the hysteresis of argon adsorption in a uniform closed end slit pore
Journal name Journal of Colloid and Interface Science   Check publisher's open access policy
ISSN 0021-9797
Publication date 2013-09-01
Sub-type Article (original research)
DOI 10.1016/j.jcis.2013.04.052
Volume 405
Start page 201
End page 210
Total pages 10
Place of publication Maryland Heights, MO, United States
Publisher Academic Press
Collection year 2014
Language eng
Formatted abstract
• Hysteresis occurs in closed end pore because of the structural change of adsorbate.
• The shape of meniscus changes because of preferential adsorption at the interface.
• In desorption, the meniscus shape is constant because of constant adsorbed layer.
• The hysteresis loop is larger for longer pores and disappears for very short pores.

We present a molecular simulation study of adsorption and desorption in slit mesopores of uniform width with one end closed and explore the effects of pore dimensions (width and length), temperature and surface affinity on the hysteresis loop: its position, lower and upper closure points, area and shape. Our results show that the metastability, brought about by structural change in the adsorbate, is the reason for the existence of hysteresis, and contrast with reports suggesting that reversibility invariably prevails for adsorption in closed end pores. The shape, area and position of the hysteresis loop are complex functions of pore width, length and temperature. We establish a parametric map of the boundary separating reversible and hysteretic regions. Our simulation results also show a number of interesting observations that have not been previously reported or generally recognised: (1) the fluid within the core of the pore behaves like a bulk liquid as the pore is progressively filled, via the movement of the meniscus from the closed end to the pore mouth, but as the pore fills, the fluid in the core becomes structured, (2) the shape of the meniscus changes as adsorption progresses but is constant during desorption because of the constant thickness of the adsorbed layer in the two-phase region, (3) the hysteresis loop is larger for a longer pore, (4) the area of the hysteresis loop increases with pore width up to a certain width, beyond which it decreases and finally disappears, (5) as temperature approaches the critical hysteresis temperature, the hysteresis loop area decreases, but it retains its Type H1 character.
Keyword Condensation
Closed end pores
Equilibrium phase-transition
Capillary condensation
Stepped surfaces
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2014 Collection
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Citation counts: TR Web of Science Citation Count  Cited 10 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 10 times in Scopus Article | Citations
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