用汞孔隙率测定法和气体吸附法测定固体材料的孔径分布和孔隙率.第2部分:用气体吸附法分析纳米孔

[中文适用范围]： 该文件描述了一种通过物理吸附（或物理吸附）评估孔隙率和孔径分布的方法。 该方法仅限于在受控恒定温度下确定每单位质量样品吸附的气体量作为压力的函数[1]-[9]。 用于物理吸附表征的常用吸附气体包括液氮和氩气（分别为 77 K 和 87 K）温度下的氮气、氩气、氪气以及 CO2（273 K）。 传统上，氮气和氩气分别在 77 K 和 87 K 下吸附，允许评估宽度大约在 0.45 nm 至 50 nm 范围内的孔隙，尽管温度控制和压力测量的改进允许评估更大的孔隙宽度。 273 K – 293 K 下的 CO2 吸附可应用于具有超微孔的微孔碳材料。 77 K 和 87 K 下的氪吸附用于测定小表面积材料的表面积或孔隙率，或用于分析多孔薄膜。 所述方法适用于多种多孔材料。 本文件重点介绍从低至 0.4 nm 到约 100 nm 的孔径分布的测定。 ISO 9277 中描述了表面积的测定。 为测定吸附气体量而设计的程序可分为两组： ——取决于从气相中除去的气体量的测量的程序，即测压（体积）方法； ——那些涉及测量吸附剂吸收气体的情况（即通过重量分析法直接测定质量增加）。 实际上，可以使用静态或动态技术来确定吸附的气体量。 然而，静态测压法通常被认为是在低温（即 77 K 和 87 K，分别是氮气和氩气的沸腾温度）下对氮气、氩气和氪进行物理吸附测量的最合适技术，目的是获得孔隙体积和孔径信息。 本文件仅关注测压方法的应用。 [外文原描述]： 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 CO 2 (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. CO 2 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.