Significance and Use

The test method has two main functions: first, it provides data useful for establishing the pore size distribution of catalyst materials, which in turn may influence their performance; and second, it serves as a laboratory test which may be used to study porosity changes that may occur during the manufacture and evaluation of catalysts.

1. Scope

1.1 This test method covers the determination of nitrogen adsorption and desorption isotherms of catalysts and catalyst carriers at the boiling point of liquid nitrogen. A static volumetric measuring system is used to obtain sufficient equilibrium adsorption points on each branch of the isotherm to adequately define the adsorption and desorption branches of the isotherm. Thirty points evenly spread over the isotherm is considered to be the minimum number of points that will adequately define the isotherm.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D3663 Test Method for Surface Area of Catalysts and Catalyst Carriers

D3766 Terminology Relating to Catalysts and Catalysis

E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods

E456 Terminology Relating to Quality and Statistics

E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

Keywords

adsorption; catalysts; desorption; isotherms; nitrogen gas; volumetric; Catalysts/catalyst carriers; Dead-space analysis; Desorption isotherms; Isotherm techniques; Nitrogen adsorption; Performance--petroleum products/applications; Pore distribution; Porosity; Static volumetric measurement; Volumetric measurement--petroleum products;

ICS Code

ICS Number Code 17.060 (Measurement of volume, mass, density, viscosity); 71.040.30 (Chemical reagents)

DOI: 10.1520/D4222-03R08

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ASTM D4222