ASTM_D_5357_-_19.pdf

Designation:D535719Standard Test Method forDetermination of Relative Crystallinity of Zeolite Sodium Aby X-ray Diffraction1This standard is issued under the fixed designation D5357;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 a procedure for determining therelative crystallinity of zeolite sodium A(zeolite NaA)usingselected peaks from the X-ray diffraction pattern of the zeolite.1.2 The term“intensity of an X-ray powder diffraction(XRD)peak”refers to the“integral intensity,”either the area orcounts under the peak or the product of the peak height and thepeak width at half height.1.3 This test method provides a number that is the ratio ofintensity of portions of the XRD pattern of the sample tointensity of the corresponding portion of the pattern of areference zeolite NaA.The intensity ratio,expressed as apercentage,is then labeled relative crystallinity of NaA.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D3906 Test Method for Determination of Relative X-rayDiffractionIntensitiesofFaujasite-TypeZeolite-Containing MaterialsE177 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.Summary of Test Method3.1 The XRD patterns of the zeolite NaA or zeolite NaA-containing sample and the reference sample(NaA)are ob-tained under the same conditions.A comparison of the sums ofintensities of six strong peaks in the 1132 2 range is made,giving relative crystallinity of NaA.This type of comparison iscommonly used in zeolite technology and is often referred to as“%crystallinity.”4.Significance and Use4.1 Zeolite NaA has been used as an active component inmolecular sieves employed as desiccants for natural gas,process gas streams,sealed insulated windows,and as a builder(water softener)in household laundry detergents.4.2 This X-ray procedure is designed to allow a reporting ofthe relative degree of crystallization of NaAin the manufactureof NaA.The relative crystallinity number has proven useful intechnology,research,and specifications.4.3 Drastic changes in intensity of individual peaks in theXRD pattern of NaA can result from changes in distribution ofelectron density within the unit cell of the NaA zeolite.Theelectron density distribution is dependent upon the extent offilling of pores in the zeolite with guest molecules,and on thenature of the guest molecules.In this XRD method,the guestmolecule H2O completely fills the pores.Intensity changesmay also result if some or all of the sodium cations in NaA areexchanged by other cations.4.4 Drastic changes in overall intensity can result fromchanges in X-ray absorption attributed to non-crystallinephases,if present,in a NaA sample.If non-zeolite crystallinephases are present,their diffraction peaks may overlap withsome of the NaAdiffraction peaks selected for this test method.If there is reason to suspect the presence of such components,then NaA peaks free of interference should be chosen foranalysis.1This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.05 on Zeolites.Current edition approved April 1,2019.Published April 2019.Originallyapproved in 1993.Last previous edition approved in 2013 as D5357 03(2013).DOI:10.1520/D5357-19.2For 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technica