The lower closure point in adsorption hysteresis of the capillary condensation type

Burgess, Christine; Everett, D. H.

doi:10.1016/0021-9797(70)90014-7

Cited by 102 publications

(47 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, the density and solvation force of a fluid confined between to plates is seen to oscillate widely as a result of packing constraints. While the slope found experimentally is consistent with Equation 1, the magnitude of the tensile stress that is induced in the fluid is considerably beyond the predicted tensile strength of the bulk liquid[l6], [11]. An additional point, is that for a system in which the stress is a result of the tensile state of the liquid at reduced P/P,, one would expect the stress to disappear when the pores emptied, so that a maximum in tensile stress would be observed at the point that the pores begin to empty.…”

Section: Resultssupporting

confidence: 54%

Preparation of Microporous Films with Sub Nanometer Pores and their Characterization Using Stress and FTIR Measurements

et al. 1996

View full text Add to dashboard Cite

We have used a novel technique, measurement of stress isotherms in microporous thin films, as a means of characterizing porosity. The stress measurement was carried out by applying sol-gel thin films on a thin silicon substrate and monitoring the curvature of the substrate under a controlled atmosphere of various vapors. The magnitude of macroscopic bending stress developed in microporous films depends on the relative pressure and molar volume of the adsorbate and reaches a value of 180 MPa for a relative vapor pressure, PPo = 0.001, of methanol. By using a series of molecules, and observing both the magnitude and the kinetics of stress development while changing the relative pressure, we have determined the pore size of microporous thin films. FTIR measurements were used to acquire adsorption isotherms and to compare pore emptying to stress development. about 80% of the change in stress takes place with no measurable change in the amou9t adsorbed. We show that for sol-gel films, pore diameters can be controlled in the range of 5 -8 A by "solvent templating".

show abstract

Section: Resultssupporting

confidence: 54%

Preparation of Microporous Films with Sub Nanometer Pores and their Characterization Using Stress and FTIR Measurements

et al. 1996

View full text Add to dashboard Cite

show abstract

“…It seems to indicate that the evaporation occurs at the same pressure for pores of different diameters around of 4 nm (in the case of nitrogen) as if the stretched liquid were broken at a definite negative pressure. This argument is in line with the tensile strength hypotheses (Kadlec and Dubinin, 1969;Burgess et al, 1970;Selvam et al, 2001). However, so far this hypothesis has not been justified with the molecular approaches.…”

Section: Introductionsupporting

confidence: 52%

Modeling of Adsorption in Finite Cylindrical Pores by Means of Density Functional Theory

Ustinov

2005

Adsorption

View full text Add to dashboard Cite

Adsorption of argon at its boiling point in finite cylindrical pores is considered by means of the non-local density functional theory (NLDFT) with a reference to MCM-41 silica. The NLDFT was adjusted to amorphous solids, which allowed us to quantitatively describe argon adsorption isotherm on nonporous reference silica in the entire bulk pressure range. In contrast to the conventional NLDFT technique, application of the model to cylindrical pores does not show any layering before the phase transition in conformity with experimental data. The finite pore is modeled as a cylindrical cavity bounded from its mouth by an infinite flat surface perpendicular to the pore axis. The adsorption of argon in pores of 4 and 5 nm diameters is analyzed in canonical and grand canonical ensembles using a two-dimensional version of NLDFT, which accounts for the radial and longitudinal fluid density distributions. The simulation results did not show any unusual features associated with accounting for the outer surface and support the conclusions obtained from the classical analysis of capillary condensation and evaporation. That is, the spontaneous condensation occurs at the vapor-like spinodal point, which is the upper limit of mechanical stability of the liquid-like film wetting the pore wall, while the evaporation occurs via a mechanism of receding of the semispherical meniscus from the pore mouth and the complete evaporation of the core occurs at the equilibrium transition pressure. Visualization of the pore filling and empting in the form of contour lines is presented.

show abstract

“…The increased calcination temperature of Ce60-700°C resulted in notable decreases of the surface area and pore volume and an increase of the average pore diameter compared to Ce60. Isotherms for the samples with more than 40% zirconia content exhibited hysteresis loops similar to a Type H2 hysteresis [38], which is indicative of rapid desorption due to changes in the properties of the adsorbed fluid [39]. Therefore, only the adsorption branch of the isotherm was used for the BJH calculations.…”

Section: Composition Surface Area and Porosity Of The Catalystsmentioning

confidence: 99%

Kinetics of hydrogen activation on ceria–zirconia

Schimming

Foo

LaMont

et al. 2015

Journal of Catalysis

View full text Add to dashboard Cite

The lower closure point in adsorption hysteresis of the capillary condensation type

Cited by 102 publications

References 5 publications

Preparation of Microporous Films with Sub Nanometer Pores and their Characterization Using Stress and FTIR Measurements

Preparation of Microporous Films with Sub Nanometer Pores and their Characterization Using Stress and FTIR Measurements

Modeling of Adsorption in Finite Cylindrical Pores by Means of Density Functional Theory

Kinetics of hydrogen activation on ceria–zirconia

Contact Info

Product

Resources

About