Microporosity

Abstract

It is convenient to categorize pores into several size ranges. The largest pore diameters amenable to analysis by the Kelvin equation are about 1000 A which corresponds to relative pressures near 0.99. Pores with diameters greater than this are termed ‘macropores’ . Dubinin [74] calls pores in the Kelvin range, from about 15 to 1000 Å, ‘transitional’ and pores with diameters less than about 15 Å‘micropores’. The failure of V—t plots to pass through the origin has led to the postulation of ‘submicropores’ [75] with diameters less than about 15 Å. According to the IUPAC convention, micropores are characterized by diameters less than 20 Å, mesopores from 20 to 500 Å, and macropores larger than 500 Å.