This document deals with the characterization of porous materials having pore
widths in the macropore range of 50 nm to 500 μm. In recent years, the
development of advanced adsorbents and catalysts (e.g., monoliths having
hierarchical pore networks) has brought about a renewed interest in macropore
structures. Mercury intrusion–extrusion porosimetry is a well-established
method, which is at present the most widely used for determining the macropore
size distribution. However, because of the reservations raised by the use of
mercury, it is now evident that the principles involved in the application of
mercury porosimetry require reappraisal and that alternative methods are worth
being listed and evaluated. The reliability of mercury porosimetry is discussed
in the first part of the report along with the conditions required for its safe
use. Other procedures for macropore size analysis, which are critically
examined, include the intrusion of other non-wetting liquids and certain wetting
liquids, capillary condensation, liquid permeation, imaging, and image analysis.
The statistical reconstruction of porous materials and the use of macroporous
reference materials (RMs) are also examined. Finally, the future of macropore
analysis is discussed.
Nature of Capillary Condensation and Evaporation Processes in Ordered Porous Materials
