ASTM D4607-14(2021)

Standard Test Method for Determination of Iodine Number of Activated Carbon

SIGNIFICANCE AND USE
4.1 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 C819). 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 Terminology D2652).  
4.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 7.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2021
• ICS: 75.160.10 - Solid fuels
• Technical Committee: D28 - Activated Carbon
• Drafting Committee: D28.02 - Liquid Phase Evaluation

Relations

• Refers: ASTM D3860-98(2020) - Standard Practice for Determination of Adsorptive Capacity of Activated Carbon by Aqueous Phase Isotherm Technique
• Effective Date: 01-Jun-2020
• Refers: ASTM E287-02(2019) - Standard Specification for Laboratory Glass Graduated Burets
• Effective Date: 01-Jul-2019
• Refers: ASTM E288-10(2017) - Standard Specification for Laboratory Glass Volumetric Flasks
• Effective Date: 01-Nov-2017
• Refers: ASTM D3860-98(2014) - Standard Practice for Determination of Adsorptive Capacity of Activated Carbon by Aqueous Phase Isotherm Technique
• Effective Date: 01-Jul-2014
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM E11-13 - Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves
• Effective Date: 01-Oct-2013
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E287-02(2012) - Standard Specification for Laboratory Glass Graduated Burets
• Effective Date: 01-Nov-2012
• Refers: ASTM D2652-11 - Standard Terminology Relating to Activated Carbon
• Effective Date: 15-Jun-2011
• Refers: ASTM E177-10 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2010
• Refers: ASTM E288-10 - Standard Specification for Laboratory Glass Volumetric Flasks
• Effective Date: 01-Apr-2010
• Refers: ASTM D2867-09 - Standard Test Methods for Moisture in Activated Carbon
• Effective Date: 01-Nov-2009
• Refers: ASTM E11-09e1 - Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves
• Effective Date: 01-May-2009
• Refers: ASTM E177-08 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2008
• Refers: ASTM D3860-98(2008) - Standard Practice for Determination of Adsorptive Capacity of Activated Carbon by Aqueous Phase Isotherm Technique
• Effective Date: 01-Aug-2008

Overview

ASTM D4607-14(2021) is the internationally recognized standard test method for the determination of the iodine number of activated carbon. Published and maintained by ASTM International, this standard provides a reliable procedure for evaluating the relative activation level-specifically, the porosity-of both unused and reactivated carbon materials. The iodine number reported as milligrams of iodine adsorbed per gram of activated carbon serves as a relative indicator of the material’s ability to adsorb substances from aqueous solutions. This method is essential for manufacturers, users, and quality assurance teams seeking consistent and comparable assessments of activated carbon performance.

Key Topics

• Iodine Number Definition: Measures the amount of iodine (in mg) adsorbed by 1 g of activated carbon, reflecting porosity and relative activation.
• Scope of Application: Applies to both unused and reactivated activated carbons, using standardized procedures and reagents.
• Test Method Summary: Based on a three-point adsorption isotherm, the procedure involves contacting carbon samples of varying weights with a standard iodine solution, then measuring the amount of iodine remaining by titration.
• Significance and Limitations:
  • The iodine number is a relative measure of porosity and does not directly quantify the capacity of activated carbon to adsorb other chemical species.
  • The relationship between iodine number and surface area may vary depending on the carbon’s raw material, processing, and pore distribution.
  • Measurement may be affected by the presence of volatiles, sulfur, or water extractables.
• Units and Safety: All measurements are reported in SI units, and users must adhere to appropriate safety and environmental regulations when performing the test.

Applications

The ASTM D4607-14(2021) iodine number test is widely used in industries where activated carbon plays a critical role in purification, separation, and filtration processes. Key application areas include:

• Water and Wastewater Treatment: Ensuring activated carbon meets the necessary porosity specifications for removing organic contaminants from water supplies.
• Industrial Processing: Quality control in the production of activated carbon for use in food and beverage processing, pharmaceuticals, and air purification.
• Environmental Compliance: Demonstrating conformity to regulatory requirements by documenting the adsorptive capacity of activated carbon used in emissions control and remediation projects.
• Material Selection and Quality Assurance: Supporting procurement and selection processes by providing a standardized metric for comparing different activated carbon products.

This standard is also valuable for laboratories conducting research and development on adsorption materials, offering a repeatable and recognized benchmark for experimental comparisons.

Related Standards

For professionals utilizing ASTM D4607-14(2021), familiarity with related standards enhances testing integrity and ensures compatibility across procedures:

• ASTM D2652: Terminology relating to activated carbon.
• ASTM D2867: Test methods for moisture in activated carbon.
• ASTM D3860: Practice for determination of adsorptive capacity of activated carbon by aqueous phase isotherm technique.
• ASTM E11: Specification for woven wire test sieve cloth and test sieves.
• ASTM E287, E288: Specifications for volumetric laboratory glassware.
• ASTM D1193: Specification for reagent water.
• NIST Circular 602: Testing of glass volumetric apparatus (for equipment calibration).

By adhering to ASTM D4607-14(2021) and these related documents, organizations and laboratories can ensure the accuracy, repeatability, and international acceptance of their activated carbon testing results.

---

Keywords: ASTM D4607, activated carbon, iodine number, adsorption capacity, porosity measurement, water treatment, carbon testing standards, quality control, ASTM International, laboratory procedures.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4607 − 14 (Reapproved 2021)
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 E11 Specification for Woven Wire Test Sieve Cloth and Test
Sieves
1.1 Thistestmethodcoversthedeterminationoftherelative
E177 Practice for Use of the Terms Precision and Bias in
activation level of unused or reactivated carbons by adsorption
ASTM Test Methods
of iodine from aqueous solution. The amount of iodine
E287 Specification for Laboratory Glass Graduated Burets
absorbed (in milligrams) by1gof carbon using test conditions
E288 Specification for Laboratory Glass Volumetric Flasks
listed herein is called the iodine number.
E300 Practice for Sampling Industrial Chemicals
1.2 The values stated in SI units are to be regarded as
2.2 NIST Publication:
standard. No other units of measurement are included in this 4
Circular 602 Testing of Glass Volumetric Apparatus
standard.
3. Summary of Test Method
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 This test method is based upon a three-point adsorption
responsibility of the user of this standard to establish appro-
isotherm (see Practice D3860). A standard iodine solution is
priate safety, health, and environmental practices and deter-
treated with three different weights of activated carbon under
mine the applicability of regulatory limitations prior to use.
specified conditions. The carbon-treated solutions are filtered
Specific hazard statements are given in Section 7.
toseparatethecarbonfromthetreatediodinesolution(filtrate).
1.4 This international standard was developed in accor-
Iodine remaining in the filtrate is measured by titration. The
dance with internationally recognized principles on standard-
amount of iodine removed per gram of carbon is determined
ization established in the Decision on Principles for the
for each carbon dosage and the resulting data used to plot an
Development of International Standards, Guides and Recom-
adsorption isotherm. The amount of iodine adsorbed (in
mendations issued by the World Trade Organization Technical
milligrams) per gram of carbon at a residual iodine concentra-
Barriers to Trade (TBT) Committee.
tion of 0.02 N is reported as the iodine number.
3.2 Iodine concentration in the standard solution affects the
2. Referenced Documents
capacity of an activated carbon for iodine adsorption.
2.1 ASTM Standards:
Therefore, the normality of the standard iodine solution must
C819 Test Method for Specific Surface Area of Carbon or
be maintained at a constant value (0.100 6 0.001 N) for all
Graphite (Withdrawn 1987)
iodine number measurements.
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
4. Significance and Use
4.1 The iodine number is a relative indicator of porosity in
This test method is under the jurisdiction of ASTM Committee D28 on
an activated carbon. It does not necessarily provide a measure
ActivatedCarbonandisthedirectresponsibilityofSubcommitteeD28.02onLiquid
of the carbon’s ability to absorb other species. Iodine number
Phase Evaluation.
may be used as an approximation of surface area for some
Current edition approved June 1, 2021. Published June 2021. Originally
approved in 1986. Last previous edition approved in 2014 as D4607 – 14. DOI:
types of activated carbons (see Test Method C819). However,
10.1520/D4607-14R21.
it must be realized that any relationship between surface area
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and iodine number cannot be generalized. It varies with
contact ASTM Customer Service at [e-mail]. 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 − 14 (2021)
changes in carbon raw material, processing conditions, and 6.9 Sodium Carbonate.
pore volume distribution (see Terminology D2652).
7. Hazards
4.2 The presence of adsorbed volatiles, sulfur, and water
7.1 Severalpotentialhazardsareassociatedwithconducting
extractables may affect the measured iodine number of an
this test procedure. It is not the purpose of this standard to
activated carbon.
address all potential health and safety hazards encountered
5. Apparatus with its use. The user is responsible for establishing appropri-
NOTE 1—All volumetric measuring equipment should meet or exceed
ate health and safety practices before use of this test procedure.
the requirements of NIST Circular 602. Volumetric glassware meeting
Determine the applicability of federal and state regulations
these specifications is generally designated as “Class A.” See also
before attempting to use this test method.
Specifications E287 and E288.
7.2 Personnel conducting the iodine number procedure
5.1 Analytical Balance, accuracy 60.0001 g.
should be aware of potential safety and health hazards associ-
5.2 Buret, 10-mL capacity or 5-mL precision buret.
ated with the chemicals used in this procedure. The “Material
5.3 Flasks, Erlenmeyer 250-mL capacity with ground glass Safety Data Sheet” (MSDS) for each reagent listed in Section
stoppers. 6 should be read and understood. Special precautions to be
taken during use of each reagent are included on the “Material
5.4 Flask, Erlenmeyer wide-mouthed, 250-mL capacity.
Safety Data Sheet” (MSDS). First aid procedures for contact
5.5 Beakers, assorted sizes.
with a chemical are also listed on its “MSDS.” A “Material
5.6 Bottles, amber, for storage of iodine and thiosulfate Safety Data Sheet” for each reagent may be obtained from the
solutions. manufacturer. Other safety and health hazard information on
6,7,8
reagents used in this procedure is available.
5.7 Funnels, 100-mm top inside diameter.
7.3 Careful handling and good laboratory technique should
5.8 Filter Paper, 18.5-cm prefolded paper, Whatman No.
always be used when working with chemicals. Avoid contact
2V or equivalent.
withhydrochloricacidoracidvapor.Careshouldalsobetaken
5.9 Pipets, volumetric type, 5.0, 10.0, 25.0, 50.0, and
to prevent burns during heating of various solutions during this
100.0-mL capacity.
test procedure.
5.10 Volumetric Flasks,1L.
7.4 Theuserofthistestmethodshouldcomplywithfederal,
state, and local regulations for safe disposal of all samples and
5.11 Graduated Cylinders, 100 mL and 500 mL.
reagents used.
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
used in all tests. Unless otherwise indicated, it is intended that
70 mLof concentrated hydrochloric acid to 550 mLof 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
used, provided it is first ascertained that the reagent is of
8.2 Sodium Thiosulfate (0.100 N)—Dissolve 24.820 g of
sufficiently high purity to permit its use without lessening the
sodium thiosulfate in approximately 75 6 25 mL of freshly
accuracy of the determination.
boiled distilled water.Add 0.10 6 0.01 g of sodium carbonate
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
D1193 for Type II reagent water. and dilute to the mark.Allow the solution to stand at least four
days before standardizing. The solution should be stored in an
6.3 Hydrochloric Acid, concentrated.
amber bottle.
6.4 Sodium Thiosulfate, (Na S O ·5H O).
2 2 3 2
8.3 Standard Iodine Solution (0.100 6 0.001 N)—Weigh
6.5 Iodine, United States Pharmacopeia, resublimed crys-
12.700 g of iodine and 19.100 g of potassium iodide (KI) into
tals.
a beaker. Mix the dry iodine and potassium iodide. Add 2 to
5 mL of water to the beaker and stir well. Continue adding
6.6 Potassium Iodide.
small increments of water (approximately 5 mL each) while
6.7 Potassium Iodate, primary standard.
stirring until the total volume is 50 to 60 mL. Allow the
6.8 Starch, soluble potato or arrowroot.
The “Chemical Safety Data Sheet” for the subject chemical is available from
Reagent Chemicals, American Chemical Society Specifications, American the Manufacturing Chemists Association, Washington, DC.
Chemical Society, Washington, DC. For suggestions on the testing of reagents not Sax,N.I.,DangerousPropertiesofIndustrialMaterials,4thedition,1975,Van
listed by the American Chemical Society, see Analar Standards for Laboratory Nostrand Reinhold Company, New York, NY.
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia NIOSH/OSHA Pocket Guide to Chemical Hazards, 1978, U.S. Department of
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, Labor, Occupational Safety and Health Administration, Washington, DC. Available
MD. from U.S. Government Printing Office, Washington, DC.
D4607 − 14 (2021)
solution to stand a minimum of4hto ensure that all crystals
I = iodine, mL.
are thoroughly dissolved. Occasional stirring during this 4-h
The titration step should be done in triplicate and the
period will aid in the dissolution. Quantitativ
...