ASTM D4607-94(2011)
(Test Method)Standard Test Method for Determination of Iodine Number of Activated Carbon
Standard Test Method for Determination of Iodine Number of Activated Carbon
SIGNIFICANCE AND USE
The iodine number is a relative indicator of porosity in an activated carbon. It does not necessarily provide a measure of the carbon's ability to absorb other species. Iodine number may be used as an approximation of surface area for some types of activated carbons (see Test Method ). However, it must be realized that any relationship between surface area and iodine number cannot be generalized. It varies with changes in carbon raw material, processing conditions, and pore volume distribution (see Definitions D2652).
The presence of adsorbed volatiles, sulfur; and water extractables may affect the measured iodine number of an activated carbon.
SCOPE
1.1 This test method covers the determination of the relative activation level of unused or reactivated carbons by adsorption of iodine from aqueous solution. The amount of iodine absorbed (in milligrams) by 1 g of carbon using test conditions listed herein is called the iodine number.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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. Specific hazard statements are given in Section 7.
General Information
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D4607 − 94(Reapproved 2011)
Standard Test Method for
Determination of Iodine Number of Activated Carbon
This standard is issued under the fixed designation D4607; 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 2.2 NIST Publication:
Circular 602—Testing of Glass Volumetric Apparatus
1.1 Thistestmethodcoversthedeterminationoftherelative
activation level of unused or reactivated carbons by adsorption
3. Summary of Test Method
of iodine from aqueous solution. The amount of iodine
absorbed (in milligrams) by1gof carbon using test conditions
3.1 This test method is based upon a three-point adsorption
listed herein is called the iodine number.
isotherm (see Practices D3860). A standard iodine solution is
treated with three different weights of activated carbon under
1.2 The values stated in SI units are to be regarded as
specifiedconditions.Thecarbontreatedsolutionsarefilteredto
standard. No other units of measurement are included in this
separate the carbon from the treated iodine solution (filtrate).
standard.
Iodine remaining in the filtrate is measured by titration. The
1.3 This standard does not purport to address all of the
amount of iodine removed per gram of carbon is determined
safety concerns, if any, associated with its use. It is the
for each carbon dosage and the resulting data used to plot an
responsibility of the user of this standard to establish appro-
adsorption isotherm. The amount of iodine adsorbed (in
priate safety and health practices and determine the applica-
milligrams) per gram of carbon at a residual iodine concentra-
bility of regulatory limitations prior to use. Specific hazard
tion of 0.02 N is reported as the iodine number.
statements are given in Section 7.
3.2 Iodine concentration in the standard solution affects the
2. Referenced Documents
capacity of an activated carbon for iodine adsorption.
Therefore, the normality of the standard iodine solution must
2.1 ASTM Standards:
be maintained at a constant value (0.100 6 0.001 N ) for all
C819 Test Method for Specific Surface Area of Carbon or
iodine number measurements.
Graphite (Withdrawn 1987)
D1193 Specification for Reagent Water
3.3 The apparatus required consists of various laboratory
D2652 Terminology Relating to Activated Carbon
glasswareusedtopreparesolutionsandcontactcarbonwiththe
D2867 Test Methods for Moisture in Activated Carbon
standard iodine solution. Filtration and titration equipment are
D3860 Practice for Determination ofAdsorptive Capacity of
also required.
Activated Carbon by Aqueous Phase Isotherm Technique
E11 Specification for Woven Wire Test Sieve Cloth and Test
4. Significance and Use
Sieves
4.1 The iodine number is a relative indicator of porosity in
E177 Practice for Use of the Terms Precision and Bias in
an activated carbon. It does not necessarily provide a measure
ASTM Test Methods
of the carbon’s ability to absorb other species. Iodine number
E287 Specification for Laboratory Glass Graduated Burets
may be used as an approximation of surface area for some
E288 Specification for Laboratory Glass Volumetric Flasks
types of activated carbons (see Test Method C819). However,
E300 Practice for Sampling Industrial Chemicals
it must be realized that any relationship between surface area
and iodine number cannot be generalized. It varies with
This test method is under the jurisdiction of ASTM Committee D28 on
changes in carbon raw material, processing conditions, and
ActivatedCarbonandisthedirectresponsibilityofSubcommitteeD28.02onLiquid
pore volume distribution (see Definitions D2652).
Phase Evaluation.
Current edition approved March 1, 2011. Published May 2011. Originally
4.2 The presence of adsorbed volatiles, sulfur; and water
approved in 1986. Last previous edition approved in 2006 as D4607 – 94 (2006).
extractables may affect the measured iodine number of an
DOI: 10.1520/D4607-94R11.
activated carbon.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
The last approved version of this historical standard is referenced on Available from National Institute of Standards and Technology (NIST), 100
www.astm.org. Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4607 − 94 (2011)
5. Apparatus ate health and safety practices before use of this test procedure.
NOTE 1—All volumetric measuring equipment should meet or exceed
Determine the applicability of federal and state regulations
the requirements of NIST Circular 602. Volumetric glassware meeting
before attempting to use this test method.
these specifications is generally designated as “Class A”. See also
Specifications E287 and E288. 7.2 Personnel conducting the iodine number procedure
should be aware of potential safety and health hazards associ-
5.1 Analytical Balance, accuracy 60.0001 g.
ated with the chemicals used in this procedure. The “Material
5.2 Buret, 10-mL capacity or 5-mL precision buret.
Safety Data Sheet” (MSDS) for each reagent listed in Section
5.3 Flasks, Erlenmeyer 250-mL capacity with ground glass 6 should be read and understood. Special precautions to be
stoppers. taken during use of each reagent are included on the “Material
Safety Data Sheet” (MSDS). First aid procedures for contact
5.4 Flask, Erlenmeyer wide-mouthed, 250-mL capacity.
with a chemical are also listed on its “MSDS.” A “Material
5.5 Beakers, assorted sizes.
Safety Data Sheet” for each reagent may be obtained from the
manufacturer. Other safety and health hazard information on
5.6 Bottles, amber, for storage of iodine and thiosulfate
6,7,8
solutions. reagents used in this procedure is available.
5.7 Funnels, 100-mm top inside diameter. 7.3 Careful handling and good laboratory technique should
always be used when working with chemicals. Avoid contact
5.8 Filter Paper, 18.5-cm prefolded paper, Whatman No.
withhydrochloricacidoracidvapor.Careshouldalsobetaken
2V or equivalent.
to prevent burns during heating of various solutions during this
5.9 Pipets, volumetric type, 5.0, 10.0, 25.0, 50.0, and
test procedure.
100.0-mL capacity.
7.4 Theuserofthistestmethodshouldcomplywithfederal,
5.10 Volumetric Flasks,1L.
state, and local regulations for safe disposal of all samples and
reagents used.
5.11 Graduated Cylinders, 100 mL and 500 mL.
6. Reagents
8. Preparation of Solutions
6.1 Purity of Reagents—Reagent grade chemicals shall be
8.1 Hydrochloric Acid Solution (5 % by weight)—Add 70
used in all tests. Unless otherwise indicated, it is intended that
mL of concentrated hydrochloric acid to 550 mL of distilled
all reagents shall conform to the specifications of the Commit-
water and mix well. A graduated cylinder may be used for
tee onAnalytical Reagents of theAmerican Chemical Society,
measurement of volume.
where such specifications are available. Other grades may be
8.2 Sodium Thiosulfate (0.100 N)—Dissolve 24.820 g of
used, provided it is first ascertained that the reagent is of
sodium thiosulfate in approximately 75 6 25 mL of freshly
sufficiently high purity to permit its use without lessening the
boiled distilled water.Add 0.10 6 0.01 g of sodium carbonate
accuracy of the determination.
tominimizebacterialdecompositionofthethiosulfatesolution.
6.2 Purity of Water—References to water shall be under-
Quantitatively transfer the mixture to a 1-L volumetric flask
stood to mean reagent water conforming to Specification
and dilute to the mark. Allow the solution to stand at least 4
D1193 for Type II reagent water.
days before standardizing. The solution should be stored in an
amber bottle.
6.3 Hydrochloric Acid, concentrated.
8.3 Standard Iodine Solution (0.100 6 0.001 N)—Weigh
6.4 Sodium Thiosulfate, (Na S O ·5H O).
2 2 3 2
12.700 g of iodine and 19.100 g of potassium iodide (KI) into
6.5 Iodine, United States Pharmacopeia, resublimed crys-
a beaker. Mix the dry iodine and potassium iodide.Add 2 to 5
tals.
mLof water to the beaker and stir well. Continue adding small
6.6 Potassium Iodide.
increments of water (approximately 5 mL each) while stirring
until the total volume is 50 to 60 mL. Allow the solution to
6.7 Potassium Iodate, primary standard.
stand a minimum of4hto ensure that all crystals are
6.8 Starch, soluble potato or arrowroot.
thoroughly dissolved. Occasional stirring during this 4-h pe-
6.9 Sodium Carbonate.
riod will aid in the dissolution. Quantitatively transfer to a 1-L
volumetric flask and fill to the mark with distilled water. It is
7. Hazards
important that the standard iodine solution has an iodide-to-
iodine weight ratio of 1.5 to 1. Store the solution in an amber
7.1 Severalpotentialhazardsareassociatedwithconducting
bottle.
this test procedure. It is not the purpose of this standard to
address all potential health and safety hazards encountered
with its use. The user is responsible for establishing appropri-
The “Chemical Safety Data Sheet” for the subject chemical is available from
the Manufacturing Chemists Association, Washington, DC.
5 7
“Reagent Chemicals,American Chemical Society Specifications,”Am. Chemi- Sax, N. I., Dangerous Properties of Industrial Materials , 4th edition, 1975,
cal Soc., Washington, DC. For suggestions on the testing of reagents not listed by Van Nostrand Reinhold Company, New York, NY.
theAmerican Chemical Society, see “Reagent Chemicals and Standards,” by Joseph NIOSH/OSHA Pocket Guide to Chemical Hazards, 1978, U.S. Department of
Rosin, D. Van Nostrand Co., Inc., New York, NY, and the “United States Labor, Occupational Safety and Health Administration, Washington, DC. Available
Pharmacopeia.” from U.S. Government Printing Office, Washington, DC.
D4607 − 94 (2011)
8.4 Potassium Iodate Solution (0.1000 N)—Dry 4 or more 10. Procedure
gram
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