ABSTRACT
This chapter presents the methodology for the characterization of nanoporous materials will be presented, applying basically the capillary condensation of vapors, which, as is very well known, is the primary method of assessment of the mesoporosity of nanoporous materials. Capillary condensation of vapors in the pores of solids is a prominent example of phase transitions in confined fluids. During capillary condensation, the pore walls are first covered by a multiplayer adsorbed film at the beginning of pore condensation. The Kelvin–Cohan equation gives a correlation between the pore diameter and the pore condensation pressure, predicting that pore condensation shifts to a higher relative pressure with an increasing pore diameter and temperature. In the nonlocal density functional theory approach, the adsorption and desorption isotherms in pores are calculated based on the intermolecular potentials of fluid–fluid and solid–fluid interactions, considering that each individual pore has a fixed geometry and is open, and in contact with the bulk adsorbate fluid.
