Characterization of pore wall heterogeneity in nanoporous carbons using adsorption: the slit pore model revisited

Journal Article · Thu Sep 16 04:00:00 EDT 2004 · Journal of Physical Chemistry B

DOI:https://doi.org/10.1021/jp049048f· OSTI ID:20544549

Nguyen, T X; Bhatia, S K ^[1]

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1. University of Queensland, Brisbane, Qld. (Australia). Division of Chemical Engineering

In this paper, we propose a new nonlocal density functional theory characterization procedure, the finite wall thickness model, for nanoporous carbons, whereby heterogeneity of pore size and pore walls in the carbon is probed simultaneously. We determine the pore size distributions and pore wall thickness distributions of several commercial activated carbons and coal chars, with good correspondence with X-ray diffraction. It is shown that the conventional infinite wall thickness approach overestimates the pore size slightly. Pore-pore correlation has been shown to have a negligible effect on prediction of pore size and pore wall thickness distributions for small molecules such as argon used in characterization. By utilizing the structural parameters (pore size and pore wall thickness distribution) in the generalized adsorption isotherm (GAI) we are able to predict adsorption uptake of supercritical gases in BPL and Norit RI Extra carbons, in excellent agreement with experimental adsorption uptake data up to 60 MPa. The method offers a useful technique for probing features of the solid skeleton, hitherto studied by crystallographic methods.

• OSTI ID: 20544549
• Journal Information: Journal of Physical Chemistry B, Journal Name: Journal of Physical Chemistry B Journal Issue: 37 Vol. 108; ISSN 1520-6106
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ACTIVATED CARBON
ADSORPTION
ADSORPTION ISOTHERMS
CHARS
COAL
PORE STRUCTURE
POROSITY
SIZE
THICKNESS
WALLS