A modified Horvath-Kawazoe (HK) pore size analysis method is presented in t
his paper. The new HK;model is generalized so as to account for the effect
of the temperature and the solid-fluid interaction potential strengthen the
adsorbed fluid density within a slit-shaped pore. Two representations of t
he local adsorbate density profile are considered in the modified HK model,
an 'unweighted' version similar to the original HK method in which a unifo
rm density profile is assumed; and a 'weighted' version in which a structur
ed density profile is adopted. The pore filling correlations predicted by t
he two HK models are compared with density functional theory (DFT) results
calculated using the same solid-fluid potential and potential parameters. I
t is found that the pore filling correlation of the unweighted HK model agr
ees surprisingly well with the DFT correlation for argon and nitrogen adsor
ption at 77 K. Interestingly, the weighted HK pore filling correlation is i
n poorer agreement with DFT results, even though the weighted HK model more
realistically represents the local density profile than does the unweighte
d HK approach. As in the original HK method, the modified HK models do not
describe the pore wall wetting that occurs prior to capillary condensation
in mesopores. In this respect, they remain inferior to DFT or molecular sim
ulation adsorption models. The modified HK method is, however, much more co
mputationally efficient than either DFT or molecular simulation, and it can
be conveniently implemented on a spreadsheet for interpretation of adsorbe
nt PSDs in gas-solid systems for which DFT model isotherms are not availabl
e. (C) 2001 Elsevier Science B.V. All rights reserved.