1、Designation: D 5357 03 (Reapproved 2008)e1Standard Test Method forDetermination of Relative Crystallinity of Zeolite Sodium Aby X-ray Diffraction1This standard is issued under the fixed designation D 5357; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEThe units statement in subsection 1.4 was corrected editorially in May 2008.1. Scope1.1
3、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
4、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 intensit
5、y 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 wit
6、h 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.2. Referenced Documents2.1 ASTM Standards:2D 3906 Test Method for Determination of Relative X-rayDiffraction I
7、ntensities of Faujasite-Type Zeolite-Containing MaterialsE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 456 Terminology Relating to Quality and StatisticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test M
8、ethod3.1 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 2u range is made,giving relative crystallinity of NaA. This type of comparison
9、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
10、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 individua
11、l 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
12、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
13、, 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.5. Ap
14、paratus5.1 Xray Diffractometer, equipped with computerized dataacquisition and reduction capability or with a strip chartrecorder, and using copper K-alpha radiation.1This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.05
15、on Zeolites.Current edition approved April 1, 2008. Published May 2008. Originallyapproved in 1993. Last previous edition approved in 2003 as D 5357-03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMSta
16、ndards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Drying Oven, set at 100C.5.3 Hydrator (Laboratory Desiccator), maintained at about58 % rel
17、ative humidity by a saturated solution of sodiumbromide, 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, prefe
18、rably with amean particle diameter of 3 to 5 microns (mean 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
19、 the sample in the hydratorand hold there at room temperature 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 re
20、sults in filling the zeolitepores with water of hydration 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 2u at 0.25/min.In
21、 the step mode, a 0.02 2u step for 2 s may be acceptable forpure 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) 2u (Cu K-a radiation)222 7
22、.104 12.46420 5.503 16.11442 4.102 21.67620 3.710 23.99642 3.289 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 f
23、actor (amplification) for the NaAreference pattern so that the 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 inc
24、reased) to provide reasonable peakheights.NOTE 4If a shortened 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 12u.8. Calculation8.1 Determine the int
25、egral peak intensity for each of the sixpeaks of 7.1.3 for both 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 a planime-ter, or3Available from
26、 National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.FIG. 1 X-Ray Diffraction Pattern of Zeolite NaAASTM Sample Z-02D 5357 03 (2008)e128.1.3 By approximating the area under the peak as theproduct of peak height and peak width at half height.8.
27、2 In all cases the integral peak intensity values aremeasured above 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 D 3906.8.3 O
28、btain a value for NaA by comparing the sums ofintegrated peak intensities (measured above background) fromthe patterns obtained in 7.1.3. Use the following equation:relative crystallinity of NaA 5SxSr3 100 % (1)where:Sx= sum of integral peak intensities for the sample, andSr= sum of the integral pea
29、k intensities for the referenceNaA.NOTE 6This test method is based on six of the most intensediffraction peaks, not because a single peak cannot be measured accu-rately, but because any single peak is more sensitive to details of crystalstructure than is the sum of these peaks.NOTE 7Peak broadening
30、can occur for a variety of reasons. Pertinentfor zeolite are the following: 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.NOT
31、E 8If non-zeolite components give XRD peaks that interfere withcertain of 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 exa
32、mple, 10.2.9. Report9.1 Report the following information:9.1.1 Relative crystallinity of NaA, and9.1.2 Non-NaA impurity peaks, if present (impurity identi-fication, if possible) and any interferences with NaA peaks.10. Precision and Bias10.1 Test ProgramAn interlaboratory study was con-ducted in whi
33、ch the named property was measured in oneseparate test material in eight separate laboratories. PracticeE 691, modified for non-uniform data sets, was followed forthe data reduction. Analysis details are in the research report.410.2 PrecisionPairs of test results obtained by a proce-dure similar to
34、that described in the study are expected to differin absolute value by less than 2.772*S, where 2.772*S is the95 % probability interval limit on the difference between twotest results, and S is the appropriate estimate of standarddeviation. Definitions and usage are given in Practices E 456and E 177
35、, respectively.Test Result(consensus mean)95 % RepeatabilityInterval(within laboratory)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-
36、ray diffraction; zeolite sodium AASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof
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39、r views known to the ASTM Committee on Standards, at the address shown below.This 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 con
40、tacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D32-1036.D 5357 03 (2008)e13
