Microporosity

Abstract

It is convenient to categorize pores into several size ranges. The largest pore radii amenable to analysis by the Kelvin equation are about 1000 Å which corresponds to relative pressures near 0.99. Pores with radii greater than this are termed ‘macropores’. Dubinin⁷⁴ calls pores in the Kelvin range, from about 15 to 1000 Å, ‘transitional’ and pores with radii 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 radii less than about 7 Å.