ISO 15901-2:2022

Pore size distribution and porosity of solid materials by mercury porosimetry and gas adsorption — Part 2: Analysis of nanopores by gas adsorption
Autor: ISO
Código ICS: 19.120


This document describes a method for the evaluation of porosity and pore size distribution by physical adsorption (or physisorption). The method is limited to the determination of the quantity of a gas adsorbed per unit mass of sample as a function of pressure at a controlled, constant temperature[1]-[9]. Commonly used adsorptive gases for physical adsorption characterization include nitrogen, argon, krypton at the temperatures of liquid nitrogen and argon (77 K and 87 K respectively) as well as CO2 (at 273 K). Traditionally, nitrogen and argon adsorption at 77 K and 87 K, respectively, allows one to assess pores in the approximate range of widths 0,45 nm to 50 nm, although improvements in temperature control and pressure measurement allow larger pore widths to be evaluated. CO2 adsorption at 273 K – 293 K can be applied for the microporous carbon materials exhibiting ultramicropores. Krypton adsorption at 77 K and 87 K is used to determine the surface area or porosity of materials with small surface area or for the analysis of thin porous films.The method described is suitable for a wide range of porous materials. This document focuses on the determination of pore size distribution from as low as 0,4 nm up to approximately 100 nm. The determination of surface area is described in ISO 9277. The procedures which have been devised for the determination of the amount of gas adsorbed may be divided into two groups:—    those which depend on the measurement of the amount of gas removed from the gas phase, i.e. manometric (volumetric) methods;—    those which involve the measurement of the uptake of the gas by the adsorbent (i.e. direct determination of increase in mass by gravimetric methods).In practice, static or dynamic techniques can be used to determine the amount of gas adsorbed. However, the static manometric method is generally considered the most suitable technique for undertaking physisorption measurements with nitrogen, argon and krypton at cryogenic temperatures (i.e. 77 K and 87 K, the boiling temperature of nitrogen and argon, respectively) with the goal of obtaining pore volume and pore size information. This document focuses only on the application of the manometric method.

Especificaciones de la Norma
Fecha de Publicación 21/01/2022
Título Secundario Distribution des dimensions des pores et porosité des matériaux solides par porosimétrie au mercure et par adsorption de gaz — Partie 2: Analyse des nanopores par adsorption de gaz
Páginas Técnicas 29
Idioma Inglés