1、Designation: D5357 03 (Reapproved 2013)Standard 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
2、 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 zeolit
3、e 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 hei
4、ght.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 Th
5、e 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-pria
6、te safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D3906 Test Method for Determination of Relative X-rayDiffraction Intensities of Faujasite-Type Zeolite-Containing MaterialsE177 Practice for Use of the Te
7、rms 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 refer
8、ence 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. Signif
9、icance 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
10、 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
11、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 resu
12、lt 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
13、 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.5. Apparatus5.1 Xray Diffractometer, equipped with computerized dataacquisition and reduction cap
14、ability or with a strip chartrecorder, and using copper K-alpha radiation.5.2 Drying Oven, set at 100C.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 Dec. 1, 2013. Published De
15、cember 2013. Originallyapproved in 1993. Last previous edition approved in 2008 as D5357 03 (2008)1.DOI: 10.1520/D5357-03R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
16、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 States15.3 Hydrator (Laboratory Desiccator), maintained at about58 % relative humidity by a saturated solution of sodiumbromide,
17、NaBr.5.4 Planimeter or Appropriate Peak Profile Analysis orDigital Integration Software, if diffractometer is not equippedwith appropriate software data analysis capability.6. Reagents and Materials6.1 NaA Powder3, as reference standard, preferably with amean particle diameter of 3 to 5 microns (mea
18、n crystal size 1to 2 microns).7. Procedure7.1 Carry out the steps (described in 7.1.1 7.1.3)inanidentical manner for both the sample and the NaA reference.7.1.1 Place about 1.5 g of finely divided sample in thedrying oven at 100C for 2 h. Cool the sample in the hydratorand hold there at room tempera
19、ture and about 58 % relativehumidity for at least 16 h.NOTE 1Grinding of course-textured samples should be done gently.Over-grinding can lead to breaking up of fine crystals and destruction ofthe zeolite.NOTE 2Drying followed by rehydration results in filling the zeolitepores with water of hydration
20、 but without an excess of moisture residingon the surface of the zeolite particles.7.1.2 Pack the sample into an XRD sample holder.7.1.3 Obtain an XRD pattern of the NaA reference byscanning over the angle range from 11 to 32 2 at 0.25/min.In the step mode, a 0.02 2 step for 2 s may be acceptable fo
21、rpure NaA, while 10 to 20 s may be necessary for lower NaAcontent samples. This scan range includes the six strongdiffraction peaks that are to be used in the calculation for “%crystallinity”:hkl index d (Angstrom) 2 (Cu K- radiation)222 7.104 12.46420 5.503 16.11442 4.102 21.67620 3.710 23.99642 3.
22、289 27.12644 2.984 29.94Fig. 1 shows a pattern for the reference zeolite NaA used intesting of this method.NOTE 31 nanometer (nm) = 10 Angstroms.7.1.3.1 If a strip chart recorder is used, set the chart drive at20 mm/min. Select the scale factor (amplification) for the NaAreference pattern so that th
23、e strong (644) peak at 29.94 isbetween 50 and 100 % of full scale. The same scale factorshould be used for the sample pattern. However, if the samplegives considerable lower peak intensity, the scale factor may bereduced (amplification increased) to provide reasonable peakheights.NOTE 4If a shortene
24、d scan program covering just the six NaA peaksis used, a range for each peak should be chosen so that a suitablebackground reading can be determined. This range, covering each peak, istypically about 12.8. Calculation8.1 Determine the integral peak intensity for each of the sixpeaks of 7.1.3 for bot
25、h the sample and the reference NaAin oneof three ways:8.1.1 From the counts recorded by a digital integratingsystem used while obtaining the pattern of 7.1.3,8.1.2 By measuring the area under the peak with aplanimeter, or3Available from National Institute of Standards and Technology (NIST), 100Burea
26、u Dr., Stop 3460, Gaithersburg, MD 20899-3460.FIG. 1 X-Ray Diffraction Pattern of Zeolite NaAASTM Sample Z-02D5357 03 (2013)28.1.3 By approximating the area under the peak as theproduct of peak height and peak width at half height.8.2 In all cases the integral peak intensity values aremeasured above
27、 background.NOTE 5Peak areas determined by the techniques described in 8.1.2 or8.1.3 must have a correction factor applied if the scale factors used for theNaA reference and sample patterns are different; see Test Method D3906.8.3 Obtain a value for NaA by comparing the sums ofintegrated peak intens
28、ities (measured above background) fromthe patterns obtained in 7.1.3. Use the following equation:relative crystallinity of NaA 5SxSr3100% (1)where:Sx= sum of integral peak intensities for the sample, andSr= sum of the integral peak intensities for the referenceNaA.NOTE 6This test method is based on
29、six of the most intense diffractionpeaks, not because a single peak cannot be measured accurately, butbecause any single peak is more sensitive to details of crystal structurethan is the sum of these peaks.NOTE 7Peak broadening can occur for a variety of reasons. Pertinentfor zeolite are the followi
30、ng: crystals may be of limited size, below 0.2m; crystals may contain disorder; and diffraction may originate fromvarying depths below the sample surface, limited by absorption, andrelated to density of packing of the sample.NOTE 8If non-zeolite components give XRD peaks that interfere withcertain o
31、f the tabulated peaks, these latter peaks should be omitted fromthe sums, both for the sample and for the reference NaA.NOTE 9Some samples of zeolite may be slightly more crystalline thana chosen reference material; see, for example, 10.2.9. Report9.1 Report the following information:9.1.1 Relative
32、crystallinity of NaA, and9.1.2 Non-NaA impurity peaks, if present (impurityidentification, if possible) and any interferences with NaApeaks.10. Precision and Bias10.1 Test ProgramAn interlaboratory study was con-ducted in which the named property was measured in oneseparate test material in eight se
33、parate laboratories. PracticeE691, modified for non-uniform data sets, was followed for thedata reduction. Analysis details are in the research report.410.2 PrecisionPairs of test results obtained by a proceduresimilar to that described in the study are expected to differ inabsolute value by less th
34、an 2.772*S, where 2.772*S is the 95 %probability interval limit on the difference between two testresults, and S is the appropriate estimate of standard deviation.Definitions and usage are given in Practices E456 and E177,respectively.Test Result(consensus mean)95 % RepeatabilityInterval(within labo
35、ratory)95 % ReproducibilityInterval(between laboratories)1.0448 0.0223 0.0276S(sample)/S(ref) (2.14 percent of mean) (2.64 percent of mean)10.3 BiasThe test method is without known bias.11. Keywords11.1 crystallinity; X-ray diffraction; zeolite sodium AASTM International takes no position respecting
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39、s standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax),
40、 or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D32-1036.D5357 03 (2013)3
