ASTM D4641 - 17 - Standard Practice for Calculation of Pore Size Distributions of Catalysts and Catalyst Carriers from Nitrogen Desorption Isotherms

ASTM D4641 - 17

Standard Practice for Calculation of Pore Size Distributions of Catalysts and Catalyst Carriers from Nitrogen Desorption Isotherms

Status : Current   Published : January 2017

Format
PDF

Format
HARDCOPY



1.1 This practice covers the calculation of pore size distributions for catalysts and catalyst carriers from nitrogen desorption isotherms. The computational procedure is particularly useful for determining how the pore volume is distributed in catalyst samples containing pores whose sizes range from approximately 1.5 to 100 nm (15 to 1000 Å) in radius. It should be used with caution when applied to isotherms for samples containing pores both within this size range and pores larger than 100 nm (1000 Å) in radius. In such instances the isotherms rise steeply near P/ P o  = 1 and the total pore volume cannot be well defined. The calculations should begin at a point on the isotherm near saturation preferably in a region near P/ P o  = 0.99, establishing an upper limit on the pore size distribution range to be studied. Simplifications are necessary regarding pore shape. A cylindrical pore model is assumed, and the method treats the pores as non-intersecting, open-ended capillaries which are assumed to function independently of each other during the adsorption or desorption of nitrogen.

Note 1:  This practice is designed primarily for manual computation and a few simplifications have been made for this purpose. For computer computation, the simplified expressions may be replaced by exact expressions.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

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.




Standard NumberASTM D4641 - 17
TitleStandard Practice for Calculation of Pore Size Distributions of Catalysts and Catalyst Carriers from Nitrogen Desorption Isotherms
StatusCurrent
Publication Date02 January 2017
Normative References(Required to achieve compliance to this standard)No other standards are normatively referenced
Informative References(Provided for Information)No other standards are informatively referenced
Descriptors Catalysts, Nitrogen adsorption, Pore size distribution
ICS71.040.30
PublisherASTM
FormatA4
DeliveryYes
Pages7
File Size136 KB
Price£40.00


 Your basket
Your basket is empty

Multi-user access to over 3,500 medical device standards, regulations, expert commentaries and other documents


Develop a PAS

Develop a fast-track standardization document in 9-12 months


Worldwide Standards
We can source any standard from anywhere in the world


Tracked Changes

Understand the changes made to a standard with our new Tracked Changes version