ASTM D3906-03(2013)
(Test Method)Standard Test Method for Determination of Relative X-ray Diffraction Intensities of Faujasite-Type Zeolite-Containing Materials
Standard Test Method for Determination of Relative X-ray Diffraction Intensities of Faujasite-Type Zeolite-Containing Materials
SIGNIFICANCE AND USE
4.1 Zeolites Y and X, particularly for catalyst and adsorbent applications, are a major article of manufacture and commerce. Catalysts and adsorbents comprising these zeolites in various forms plus binder and other components have likewise become important. Y-based catalysts are used for fluid catalytic cracking (FCC) and hydrocracking of petroleum, while X-based adsorbents are used for desiccation, sulfur compound removal, and air separation.
4.2 This X-ray procedure is designed to monitor these Y and X zeolites and catalysts and adsorbents, providing a number more or less closely related to percent zeolite in the sample. This number has proven useful in technology, research, and specifications.
4.3 Drastic changes in intensity of individual peaks in the XRD patterns of Y and X can result from changes of distribution of electron density within the unit cell of the zeolite. The electron density distribution is dependent upon the extent of filling of pores in the zeolite with guest molecules, and on the nature of the guest molecules. In this XRD method, the guest molecule H2O completely fills the pores. Intensity changes may also result if some or all of the cations in Y and X are exchanged by other cations.
4.3.1 Because of the factors mentioned in 4.3 that could vary the intensities of the XRD peaks, this XRD method will provide the best determination of relative crystallinity when the reference and sample have a similar history of preparation and composition.
4.4 Corrections are possible that can make this XRD method accurate for measuring percent zeolite in many specific situations. These corrections are well known to those skilled in X-ray diffraction. It is not practical to specify those corrections here.
SCOPE
1.1 This test method covers the determination of relative X-ray diffraction intensities of zeolites having the faujasite crystal structure, including synthetic Y and X zeolites, their modifications such as the various cation exchange forms, and the dealuminized, decationated, and ultrastable forms of Y. These zeolites have cubic symmetry with a unit cell parameter usually within the limits of 24.2 and 25.0 ˚Å (2.42 and 2.50 nm).
1.2 The samples include zeolite preparations in the various forms, and catalysts and adsorbents containing these zeolites.
1.3 The term “intensity of an X-ray powder diffraction (XRD) peak” is the “integral intensity,” either the area of counts under the peak or the product of the peak height and the peak width.
1.4 This test method provides a number that is the ratio of intensity of portions of the XRD pattern of the sample to intensity of the corresponding portion of the pattern of a reference zeolite, NaY. (Laboratories may use a modified Y or X, for example, REY as a secondary standard.) The intensity ratio, expressed as a percentage, is then labeled “% XRD intensity/NaY.”
1.5 Under certain conditions such a ratio is the percent zeolite in the sample. These conditions include:
1.5.1 The zeolite in the sample is the same as the reference zeolite.
1.5.2 The absorption for the X-rays used is the same for the zeolite and the nonzeolite portions of the sample.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D3906 − 03 (Reapproved 2013)
Standard Test Method for
Determination of Relative X-ray Diffraction Intensities of
Faujasite-Type Zeolite-Containing Materials
This standard is issued under the fixed designation D3906; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers the determination of relative 2.1 ASTM Standards:
X-ray diffraction intensities of zeolites having the faujasite E177 Practice for Use of the Terms Precision and Bias in
crystal structure, including synthetic Y and X zeolites, their ASTM Test Methods
modifications such as the various cation exchange forms, and E456 Terminology Relating to Quality and Statistics
the dealuminized, decationated, and ultrastable forms of Y. E691 Practice for Conducting an Interlaboratory Study to
These zeolites have cubic symmetry with a unit cell parameter Determine the Precision of a Test Method
usually within the limits of 24.2 and 25.0˚ Å (2.42 and 2.50
3. Summary of Test Method
nm).
3.1 The XRD patterns of the zeolite containing sample and
1.2 The samples include zeolite preparations in the various
the reference sample (NaY), are obtained under the same
forms, and catalysts and adsorbents containing these zeolites.
conditions. If the XRD pattern of the zeolite is sufficiently
1.3 The term “intensity of an X-ray powder diffraction
strong, a comparison of intensities of eight peaks is used to
(XRD) peak” is the “integral intensity,” either the area of
give % XRD intensity/NaY. For lower zeolite content intensi-
counts under the peak or the product of the peak height and the
ties of the (533) peak (23.5° with Cu Kα radiation) are
peak width.
compared to provide “% XRD intensity/NaY (533).”
1.4 This test method provides a number that is the ratio of
4. Significance and Use
intensity of portions of the XRD pattern of the sample to
intensity of the corresponding portion of the pattern of a
4.1 Zeolites Y and X, particularly for catalyst and adsorbent
reference zeolite, NaY. (Laboratories may use a modified Y or applications, are a major article of manufacture and commerce.
X, for example, REY as a secondary standard.) The intensity
Catalysts and adsorbents comprising these zeolites in various
ratio, expressed as a percentage, is then labeled “% XRD
forms plus binder and other components have likewise become
intensity/NaY.”
important. Y-based catalysts are used for fluid catalytic crack-
ing (FCC) and hydrocracking of petroleum, while X-based
1.5 Under certain conditions such a ratio is the percent
adsorbents are used for desiccation, sulfur compound removal,
zeolite in the sample. These conditions include:
and air separation.
1.5.1 The zeolite in the sample is the same as the reference
zeolite.
4.2 This X-ray procedure is designed to monitor these Y and
1.5.2 The absorption for the X-rays used is the same for the
X zeolites and catalysts and adsorbents, providing a number
zeolite and the nonzeolite portions of the sample.
more or less closely related to percent zeolite in the sample.
This number has proven useful in technology, research, and
1.6 This standard does not purport to address all of the
specifications.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.3 Drastic changes in intensity of individual peaks in the
priate safety and health practices and determine the applica-
XRD patterns of Y and X can result from changes of distribu-
bility of regulatory limitations prior to use.
tion of electron density within the unit cell of the zeolite. The
electron density distribution is dependent upon the extent of
filling of pores in the zeolite with guest molecules, and on the
nature of the guest molecules. In this XRD method, the guest
This test method is under the jurisdiction of ASTM Committee D32 on
Catalysts and is the direct responsibility of Subcommittee D32.05 on Zeolites. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2013. Published December 2013. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1980. Last previous edition approved in 2008 as D3906 – 03 (2008). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D3906-03R13. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3906 − 03 (2013)
Angle (°2θ)
FIG. 1 X-Ray Diffraction Patterns of ASTM Zeolite Samples Upper—NaY; Lower—Cracking Catalyst Intensity
Angle (°2θ)
FIG. 2 NaY—Complete Diffractometer Scan Intensity
D3906 − 03 (2013)
molecule H O completely fills the pores. Intensity changes 8.4 Obtain a first XRD pattern by scanning over the angle
may also result if some or all of the cations in Y and X are range from 14 to 35° 2θ at about 1°/min and using other
exchanged by other cations. instrument parameters best suited to the diffractometer.
4.3.1 Because of the factors mentioned in 4.3 that could 8.4.1 Ifastripchartrecorderisused,setthechartdriveat10
vary the intensities of the XRD peaks, this XRD method will mm/min. Select the scale factor (amplification) for the NaY
providethebestdeterminationofrelativecrystallinitywhenthe reference pattern so that the strong (533) peak at 23.6° is
reference and sample have a similar history of preparation and between 50 and 100 % of full scale. For the sample the scale
composition. factor may be reduced (amplification increased) to provide
reasonable peak heights. If possible the height of the (533)
4.4 Corrections are possible that can make this XRD
peak for the sample should be at least 10 % of full scale. Fig.
methodaccurateformeasuringpercentzeoliteinmanyspecific
1 shows such patterns for the reference NaY and for a
situations.These corrections are well known to those skilled in
zeolite-containing catalyst.
X-ray diffraction. It is not practical to specify those corrections
here. 8.5 If this first pattern of the sample contains XRD peaks of
some nonfaujasite components, it must be established whether
5. Apparatus this may cause interference in the following steps. (Fig. 2 is a
complete diffractometer scan for NaY.)
5.1 X-ray Diffractometer, equipped with a strip chart re-
corder or with computerized data acquisition and reduction 8.6 Obtain a second XRD pattern by scanning over a small
capability, using copper K-alpha radiation. angle range at ⁄4 °⁄min.
5.2 Drying Oven, set at 110°C.
NOTE3—Longerscantimeswillberequiredforsampleshavingalower
content of zeolite. For example 0.02º 2θ/step for 1 s may be acceptable for
5.3 Hydrator (Glass Laboratory Desiccator), maintained at
a pure NaY while 10 to 20 s counting times per step may be required for
35 % relative humidity by a saturated solution of salt, such as
a low level of zeolite samples.
CaCl ·6H O.
2 2
8.6.1 The preferred angle range is from 22.5 to 25° 2θ, the
5.4 Planimeter or Appropriate Peak Profile Analysis or
(533) peak. Fig. 3 shows such a pattern for NaY. If interference
Digital Integration Software—If XRD is not equipped with
rules out this range, choose for this step (for both the sample
appropriate software data analysis capability.
and the reference patterns) one of the following angle ranges:
14.0 to 17.0°, (331) peak
6. Reagents and Materials
19.0 to 22.0°, (440) peak
25.5 to 28.0°, (642) peak
6.1 NaY Powder and RE Exchanged Y Powder, as reference
standards.
NOTE 4—These ranges in Step 8.6 each are of such width that two or
more zeolite peaks are included. Such wide ranges are specified to allow
for the variation in peak position over the range of unit cell dimensions
7. Sampling
24.2 to 25.0 Å (2.42 to 2.50 mm) and to provide a background reading on
7.1 Conduct sampling by splitting a large portion of the
each side of the main peak. Within each range the major zeolite peak will
sample and reference material homogeneously. be the desired one. See Appendix X1 of peak positions.
7.2 Divide the sample and reference finely to permit pack-
9. Calculation
ing of the materials into XRD sample holders.
9.1 Obtain an integral peak intensity for each of the eight
NOTE 1—The best test to determine if grinding is required is to try to
peaks (measured above background) chosen from the patterns
packthesampleintheholder.Overgrindingcanleadtobreakingupoffine
from 8.4, for both the sample and reference, in one of three
crystals and even destruction of zeolite.
ways:
9.1.1 By approximating the area under the peak as the
8. Procedure
product of peak height and peak width at half height (use 9.2
8.1 Carry out the following steps, 8.2 through 8.5,inan
for appropriate area calculations), or
identical manner for both the sample and the reference
9.1.2 By measuring the area under the peak with a planim-
material, NaY.
eter (use 9.3 for area by planimeter), or
8.2 Place about 3 to5gofthe sample in the drying oven at
9.1.3 From the counts recorded by a digital integrating
110°C for 1 h. Cool the sample in the hydrator and hold at system (use 9.4 for integrator counts calculation).
room temperature and 35 % relative humidity for at least 16 h.
9.2 Approximate Area Calculation:
9.2.1 Ascale factor correction, SFC, is the ratio of the scale
NOTE 2—Drying, followed by rehydration, results in filling the zeolite
pores with water of hydration but without an excess of moisture residing
factor used for the sample pattern, SF , to that used for the
X
on the surface of the zeolite particles.
reference pattern, SF .Thus, SFC = SF /SF . Scale factors are
R X R
8.3 Pack the humidity-conditioned sample into an XRD
usually expressed in terms of counts per second corresponding
sample holder. to full scale on the recorder. They are related inversely to
amplification.
9.2.2 Measure the width of the (533) or alternative peaks
obtained in Step 8.6. The width is measured at half the peak
Available from National Institute of Standards and Technology (NIST), 100
Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460. height, that is, half way between the background and the peak
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