ASTM D5357-2003 Standard Test Method for Determination of Relative Crystallinity of Zeolite Sodium A by X-Ray Diffraction《用X射线衍射法测定沸石钠A的相对结晶度用标准试验方法》.pdf

1、Designation: D 5357 03Standard 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 the case of revisio

2、n, 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.1. Scope1.1 This test method covers a procedure for determining therelative crystallinity of zeolite sodium A (zeo

3、lite 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 te

4、st 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 This standard doe

5、s 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Stan

6、dards:D 3906 Test Method for Determination of Relative X-rayDiffraction Intensities of Faujasite-Type Zeolite-Containing Materials2E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3E 456 Terminology Relating to Quality and Statistics3E 691 Practice for Conducting an Interlab

7、oratory Study toDetermine the Precision of a Test Method33. 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 2u

8、 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,proces

9、s 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 NaA in the manufactureof NaA. The relative crystallinity number has proven useful intechnolo

10、gy, 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 z

11、eolite 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 f

12、romchanges 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 NaA diffraction peaks selected for this test method.If there is reason to suspect the presence of such co

13、mponents,then NaA peaks free of interference should be chosen foranalysis.5. Apparatus5.1 Xray Diffractometer, equipped with computerized dataacquisition and reduction capability or with a strip chartrecorder, and using copper K-alpha radiation.5.2 Drying Oven, set at 100C.5.3 Hydrator (Laboratory D

14、esiccator), maintained at about58 % relative humidity by a saturated solution of sodiumbromide, NaBr.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 March 10, 2003. Published Ap

15、ril 2003. Originallyapproved in 1993. Last previous edition approved in 1998 as D 5357-98.2Annual Book of ASTM Standards, Vol 05.05.3Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 Planime

16、ter or Appropriate Peak Profile Analysis orDigital Integration Software, if diffractometer is not equippedwith appropriate software data analysis capability.6. Reagents and Materials6.1 NaA Powder4, as reference standard, preferably with amean particle diameter of 3 to 5 microns (mean crystal size 1

17、to 2 microns).7. Procedure7.1 Carry out the steps (described in 7.1.1-7.1.3) in anidentical 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 temperature and about

18、 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 but without a

19、n 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 the step mode, a 0.02 2u step for 2 s may be acceptable forpure NaA, w

20、hile 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 7.104 12.46420 5.503 16.11442 4.102 21.67620 3.710 23.99642 3.289 27.126

21、44 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 the strong (

22、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 shortened scan pro

23、gram 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 integral peak intensity for each of the sixpeaks of 7.1.3 for both the sam

24、ple and the reference NaA in 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, or8.1.3 By approximating the area under the peak as theproduct of peak height and peak

25、width at half height.4Available from 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-02D53570328.2 In all cases the integral peak intensity values aremeasured above background.NO

26、TE 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 Obtain a value for NaA by comparing the sums ofintegrated peak intensities (measur

27、ed 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 peak intensities for the referenceNaA.NOTE 6This test method is based on six of the

28、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 can occur for a variety of reasons. Pertinentfor zeolite are the following: cryst

29、als 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 of the tab

30、ulated 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 crystalli

31、nity 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 inter-laboratory study was con-ducted in which the named property was measured in oneseparate test material in eight separat

32、e laboratories. PracticeE 691, modified for non-uniform data sets, was followed forthe data reduction. Analysis details are in the research report.510.2 PrecisionPairs of test results obtained by a proce-dure similar to that described in the study are expected to differin absolute value by less than

33、 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, respectively.Test Result(consensus mean)95 % RepeatabilityInterval(within labo

34、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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38、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), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D32-1036.D5357033