Study of heat of adsorption across the capillary condensation in cylindrical pores

Wang, Yao, Do, D.D. and Nicholson, D. (2011) Study of heat of adsorption across the capillary condensation in cylindrical pores. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 380 1-3: 66-78. doi:10.1016/j.colsurfa.2011.02.016


Author Wang, Yao
Do, D.D.
Nicholson, D.
Title Study of heat of adsorption across the capillary condensation in cylindrical pores
Journal name Colloids and Surfaces A: Physicochemical and Engineering Aspects   Check publisher's open access policy
ISSN 0927-7757
1873-4359
Publication date 2011-05-05
Sub-type Article (original research)
DOI 10.1016/j.colsurfa.2011.02.016
Volume 380
Issue 1-3
Start page 66
End page 78
Total pages 13
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Abstract We have investigated the isosteric heat of argon adsorption in MCM-41 and carbon nanotubes using grand canonical Monte Carlo (GCMC) simulation, and find that the isosteric heat during the capillary condensation is practically constant irrespective of temperature, pore-curvature, and surface strength. We also studied the microscopic behavior during capillary condensation by analyzing the histogram of the number of particles, the local number fluctuation and the layer compressibility. The histograms exhibit increasingly broader peaks close to condensation which subdivide into two separate peaks, indicating the relative probability of two co-existing states. Local number fluctuation allows us to identify the boundary between the adsorbed phase and the gas phase inside the pore. The layer compressibility can be used to identify the states of the adsorbate in each layer within the adsorbed phase. Finally we propose a simple model for the heterogeneous surface of MCM-41 to simulate the effects of surface heterogeneity on the isosteric heat. This model is able to describe the experimental isosteric heat of argon adsorption at 87.3 K in MCM-41.
Keyword Adsorption
Cylindrical pores
Isosteric heat
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemical Engineering Publications
 
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