ASTM_D_4284_-_12.pdf

Designation:D428412Standard Test Method forDetermining Pore Volume Distribution of Catalysts andCatalyst Carriers by Mercury Intrusion Porosimetry1This standard is issued under the fixed designation D4284;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the porevolume distributions of catalysts and catalyst carriers by themethod of mercury intrusion porosimetry.The range of appar-ent diameters of pores for which it is applicable is fixed by theoperant pressure range of the testing instrument.This range istypically between apparent pore entrance diameters of about100 and 0.003 m(3 nm).1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous system,kidney and liver damage.Mercury,orits vapor,may be hazardous to health and corrosive tomaterials.Caution should be taken when handling mercury andmercury containing products.See the applicable product Ma-terial Safety Data Sheet(MSDS)for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional information.Users should be aware that selling mercuryand/or mercury containing products into your state or countrymay be prohibited by law.1.4 This standard does not purport to address all of thesafety problems,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardinformation is given in Section 8.2.Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 apparent pore diameterthe diameter of a pore,assumed to be cylindrical,that is intruded at a pressure,P,andis calculated with Eq 1.3.1.2 interparticle poresthose pores that occur betweenparticles when they are packed together and that are intrudedduring the test.3.1.3 intraparticle poresthose pores lying within the en-velopes of the individual catalyst particles and that are intrudedduring the test.3.1.4 intruded pore volumethe volume of mercury that isintruding into the pores during the test after this volume hasbeen corrected,if necessary,per 13.3.2.4.Summary of Test Method4.1 When a liquid does not wet a porous solid it will notvoluntarily enter the pores in the solid by capillary attraction.The nonwetting liquid(mercury in this test method)must beforced into the pores by the application of external pressure.The size of the pores that are intruded is inversely proportionalto the applied pressure.When a cylindrical pore model isassumed,the relationship between pressure and size is:d 524cos!P(1)where:d=apparent diameter of the pore being intruded,=surface tension of the mercury,=contact angle between the mercury and the solid,andP=absolute pressure causing the intrusion.4.2 The volume of the intruded pores is determined bymeasuring the volume of mercury that is forced into them atvarious pressures.Asingle-pore size distribution determinationinvolves increasing the pressure,either continuously or step-wise,and recording the measured intruded volume.1This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.01 on Physical-Chemical Properties.Current edition approved May 1,2012.Published July 2012.Originally approvedin 1983.Last previous edition approved in 2007 as D428407.DOI:10.1520/D4284-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Significance and Use5.1 This test method is intended to determine the volumedistribution of pores in catalysts and catalyst carriers withrespect to the apparent diameter of the entrances to the pores.In general,both the size and volume of pores in a catalyst affectits performance.Thus,the pore volume distribution is useful inunderstanding a catalysts performance and in specifying acatalyst that can be expected to perform in a desired manner.6.Limitations6.1 Mercury intrusion porosimetry,in common with manyother test methods,is only capable of sensing pores that areopen to the outside of a catalyst or