GB/T 21650.2-2008 in English

《GB/T 21650.2-2008压汞法和气体吸附法测定固体材料孔径分布和孔隙度 第2部分：气体吸附法分析介孔和大孔》由TC168（全国颗粒表征与分检及筛网标准化技术委员会）归口，主管部门为国家标准化管理委员会。
ＧＢ／Ｔ２１６５０《压汞法和气体吸附法测定固体材料孔径分布和孔隙度》分为３个部分,本部分为ＧＢ／Ｔ２１６５０的第２部分。本标准的本部分规定了采用气体吸附法测定空隙率和孔径分布的方法。本部分所规定的方法可适用于大范围内的多孔材料。即使某些材料的孔结构有时会受预处理或冷却制度的影响。 本部分等同采用ＩＳＯ１５９０１-２：２００６《压汞法和气体吸附法测定固体材料孔径分布和孔隙度　第２
部分：气体吸附法分析介孔和大孔》（英文版）。

Scope

This part of GB/T 21650 specifies a method for the determination of porosity and pore size distribution using the gas adsorption method, which is used for comparative rather than absolute testing. This method is limited to the determination of gas adsorption per unit mass of sample at a constant controlled temperature. This section does not specify the use of a specific adsorbent gas, but nitrogen is the most commonly used adsorbent gas, and liquid nitrogen temperature is the most commonly used analysis temperature. Other adsorbed gases are sometimes used, including oxygen, carbon dioxide, and chlorine. Other analysis temperatures are also used, including liquid oxygen and solid carbon dioxide temperatures. When using nitrogen at liquid nitrogen temperature for adsorption, the basic method of this method is to measure the variation of nitrogen adsorption with its relative pressure at 77K. This part specifies the calculation method for the distribution of mesopore size from 2nm to 50nm and the distribution of macropore size up to 100nm. Generally speaking, nitrogen adsorption is most suitable for the determination of pores with a width in the range of about 0.4 nm to 50 nm. Thanks to advances in temperature control and pressure measurement techniques, it is now possible to measure larger pore widths. The methods specified in this standard are applicable to a wide range of porous materials. Even the pore structure of some materials can sometimes be affected by pretreatment or cooling regimes. This standard specifies two types of methods for determining the amount of gas adsorbed: - measurement of the amount of gas reduced from the gas phase (i.e. gas volume method); - measurement of the amount of gas obtained by the adsorbent (i.e. gravimetric method for direct measurement of mass gain) . For practical applications, static or dynamic techniques can be used to determine gas adsorption. To calculate pore volume and pore size distributions from isotherms, one or more mathematical models need to be employed, which requires simplifying the underlying assumptions.