Specific Surface Area, Wetting, and Surface Tension of Materials from N2 Vapor Adsorption Isotherms

Narayanaswamy, Nagarajan; Ward, C. A.

doi:10.1021/acs.jpcc.9b02804

Cited by 18 publications

(66 citation statements)

References 52 publications

(135 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More successful are the BET modification by Anderson 30 and the Frenkel-Halsey-Hill 1 equation. But in some cases, for example in the adsorption on macroporous silica, their application fails 31 32 , and even the use of equation 1of the preceding cluster model 3 proposed by Ward 33 yields deviating results. The strong error of the last three isotherms is demonstrated here for the adsorption of nitrogen on macroporous silica 34 (SI, Figure S5).…”

Section: Type II Isothermsmentioning

confidence: 99%

General Cluster Sorption Isotherm

Buttersack

2021

Microporous and Mesoporous Materials

View full text Add to dashboard Cite

Section: Type II Isothermsmentioning

confidence: 99%

General Cluster Sorption Isotherm

Buttersack

2021

Microporous and Mesoporous Materials

View full text Add to dashboard Cite

“…These constants were previously assumed to act as material properties. 18,24,29 The distributions a 0 and a ζ at a given x V have the same units as M, and they are given as…”

Section: Expressions For the Zeta Adsorption Isotherm Functionmentioning

confidence: 99%

“…At some sites, there would be ζ th molecules adsorbed, but at these sites as well, there would be one adsorbed vapor molecule from each of the adsorbed components at the M g adsorption sites. The area of the substrate, A s , would then be given by 18,20,24 A N M T T ( ) ( ) By using eq 16 with eq 27, one finds that the number of adsorption sites per unit area, M, is inversely proportional to the occupied area σ A…”

Section: Expressions For the Zeta Adsorption Isotherm Functionmentioning

confidence: 99%

See 1 more Smart Citation

Specific Surface Area of Nanopowders from Argon Adsorption at 77 and 87 K: Zeta Adsorption Isotherm Approach

Narayanaswamy

Ward

2021

J. Phys. Chem. C

Self Cite

View full text Add to dashboard Cite

The surface characterization of nanopowders is widely attempted by both N2 and Ar vapor adsorption methods. They are used as complementary probe molecules because of their similarities and certain differences. However, the respective reported analyses, using the Brunauer–Emmett–Teller method, suffer from inconsistencies between the determined values of the specific surface areas, A s. We examine this issue by using the zeta adsorption isotherm approach on the reported data for both vapors on two different samples from the same batch of a nanopowder material. By assuming the equivalence of the A s determined by both of the vapors, we obtain the average occupied area of an adsorbed argon atom, σA(Ar), on silica and carbon black at the solid- and liquid-state temperatures of 77 and 87 K, respectively. We then examine the determined value of σA(Ar) by obtaining A s for other samples of the same material with varying specific areas. By transforming the adsorption data from mass-specific to area-specific, the respective thermodynamic isotherms, n SV, of Ar vapor adsorbing on silica and carbon black are obtained. The determined n SV are then used with the Gibbs adsorption equation to determine the solid surface energy, γS0, and solid–vapor interface energy, γSV, for both substrates. The obtained γSV(x V) on both substrates is used to interpret the phase transition state of the Ar adsorbate at 77 K. The determined thermodynamic isotherms for Ar and N2 vapors are further used in a comparative study to show that the Ar vapor adsorption is negligibly affected by the change in silanol concentration on the silica surface in contrast with N2 vapor adsorption.

show abstract

“…More successful are the BET modification by Anderson 30 and the Frenkel-Halsey-Hill 1 equation. But in some cases, for example in the adsorption on macroporous silica, their application fails 31 32 , and even the use of equation (1) of the preceding cluster model 3 proposed by Ward 33 yields deviating results. The strong error of the last three isotherms is demonstrated here for the adsorption of nitrogen on macroporous silica 34 (SI, Figure S5).…”

Section: Type II Isothermsmentioning

confidence: 99%

General Cluster Sorption Isotherm

Buttersack

2020

Preprint

View full text Add to dashboard Cite

Adsorption isotherms are an essential tool in chemical physics of surfaces. However, several approaches based on a different theoretical basis exist and for isotherms including capillary condensation existing approaches can fail. Here, a general isotherm equation is derived and applied to literature data both concerning type IV isotherms of argon and nitrogen in ordered mesoporous silica, and type II isotherms of disordered macroporous silica. The new isotherm covers the full range of partial pressure (10-6 - 0.7). It relies firstly on the classical thermodynamics of cluster formation, secondly on a relationship defining the free energy during the increase of the cluster size. That equation replaces the Lennard-Jones potentials used in the classical density functional theory. The determination of surface areas is not possible by this isotherm because the cross-sectional area of a cluster is unknown. Based on the full description of type IV isotherms, most known isotherms are accessible by respective simplifications.

show abstract

Specific Surface Area, Wetting, and Surface Tension of Materials from N₂ Vapor Adsorption Isotherms

Cited by 18 publications

References 52 publications

General Cluster Sorption Isotherm

General Cluster Sorption Isotherm

Specific Surface Area of Nanopowders from Argon Adsorption at 77 and 87 K: Zeta Adsorption Isotherm Approach

General Cluster Sorption Isotherm

Contact Info

Product

Resources

About