ASTM D4222-98
(Test Method)Standard Test Method for Determination of Nitrogen Adsorption and Desorption Isotherms of Catalysts By Static Volumetric Measurements
Standard Test Method for Determination of Nitrogen Adsorption and Desorption Isotherms of Catalysts By Static Volumetric Measurements
SCOPE
1.1 This test method covers the determination of nitrogen adsorption and desorption isotherms of catalysts and catalyst carriers at the boiling point of liquid nitrogen. A static volumetric measuring system is used to obtain about thirty equilibrium adsorption points on each branch of the isotherm, these points being evenly spread over the isotherm.
1.2 This standard does not purport to address all of the safety problems, 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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact
ASTM International (www.astm.org) for the latest information.
Designation: D 4222 – 98
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Determination of Nitrogen Adsorption and Desorption
1
Isotherms of Catalysts By Static Volumetric Measurements
This standard is issued under the fixed designation D 4222; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope
TH 5 temperature of manifold at initial helium pres-
1
sure, °C.
1.1 This test method covers the determination of nitrogen
TH 5 temperature of manifold after equilibration, °C.
adsorption and desorption isotherms of catalysts and catalyst
2
P 5 initial N pressure, torr.
1 2
carriers at the boiling point of liquid nitrogen. A static
T 5 manifold temperature at initial N pressure, K.
1 2
volumetric measuring system is used to obtain sufficient
T8 5 manifold temperature at initial N pressure, °C.
1 2
equilibrium adsorption points on each branch of the isotherm to
P 5 pressure after equilibration, torr.
2
adequately define the adsorption and desorption branches of
T 5 manifold temperature after equilibrrium, K.
2
the isotherm. Thirty points evenly spread over the isotherm is
T8 5 manifold temperature after equilibrium, °C.
2
considered to be the minimum number of points that will
P 5 initial N pressure during desorption, torr.
3 2
adequately define the isotherm.
T 5 manifold temperature at initial N pressure, K.
3 2
1.2 This standard does not purport to address all of the
T8 5 manifold temperature at initial N pressure, °C.
3 2
safety concerns, if any, associated with its use. It is the
P 5 pressure after equilibration during desorption,
4
responsibility of the user of this standard to establish appro-
torr.
priate safety and health practices and determine the applica-
T 5 manifold temperature after equilibration, K.
4
bility of regulatory limitations prior to use.
T8 5 manifold temperature after equilibration, °C.
4
P 5 liquid nitrogen vapor pressure, torr.
0
2. Referenced Documents
T 5 liquid nitrogen temperature, K.
s
X 5 relative pressure, P P .
2.1 ASTM Standards:
2(4) 0
3
2
V 5 volume of manifold, cm .
D 3663 Test Method for Surface Area of Catalysts
d
3
2
V 5 the dead-space volume factor, cm (STP)/torr.
s
D 3766 Terminology Relating to Catalysts and Catalysis
W 5 weight of sample, g.
s
E 177 Practice for Use of the Terms Precision and Bias in
3 W 5 tare weight of sample tube, g.
1
ASTM Test Methods
W8 5 sample + tare weight of tube after degassing, g.
3
2
E 456 Terminology Relating to Quality and Statistics
W 5 sample + tare weight of tube after adsorption, g.
2
E 691 Practice for Conducting an Interlaboratory Study to
3
V 5 volume of nitrogen in the dead-space, cm (STP).
34 ds
Determine the Precision of a Test Method
V 5 see 12.4.5.
1
V 5 see 12.4.7.
2
3. Terminology
V 5 see 12.4.8.
t
3.1 Definitions—Consult Terminology D 3766.
V 5 see 12.4.10.
ad(de)
3.2 Symbols:
4. Summary of Test Method
4.1 The sample is heater and evacuated to remove adsorbed
PH 5 initial helium pressure, torr.
1
vapors from the surface. The nitrogen adsorption branch of the
PH 5 helium pressure after equilibration, torr.
2
isotherm is determined by evacuating the sample, cooling the
sample to the boiling point of liquid nitrogen (;77.3 K), and
subsequently adding stepwise, known amounts of nitrogen gas
to the sample in such amounts that the form of the adsorption
1
This test is under the jurisdiction of ASTM Committee D-32 on Catalysts and
isotherm is adequately defined and the saturation pressure of
is the direct responsibility of Subcommittee D32.01 on Physical-Chemical Proper-
nitrogen is reached. Each additional dose of nitrogen is
ties.
Current edition approved March 10, 1998. Published November 1998. Originally introduced to the sample only after the foregoing dose of
published as D 4222 - 83. Last previous edition D 4222 - 91.
nitrogen has reached adsorption equilibrium with the sample.
2
Annual Book of ASTM Standards, Vol 05.03.
3 By definition, equilibrium is reached if the change in gas
Annual Book of ASTM Standards, Vol 14.02.
4
pressure is no greater than 0.1 torr/5 min interval. The
Adamson, A. W., Physical Chemistry of Surfaces, 3rd ed, John Wiley & Sons,
New York, NY, 1976, p. 532.
1
---------------------- Page: 1 ----------------------
NOTICE:¬This¬standard¬has¬either¬been¬superceded¬and¬replaced¬by¬a¬new¬version¬or¬discontinued.¬
Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information.¬
D 4222
desorption isotherm is determined by desorbing nitrogen from or a compres
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.