ASTM D7385-21

Standard Guide for Estimating Carbon Saturation by Temperature Rise Upon Immersion

SIGNIFICANCE AND USE
5.1 It is often useful to estimate the degree of saturation, and hence the expected remaining service life, of activated carbon that has been in use for some time. This guide is applicable when such information must be obtained fairly rapidly under field conditions without access to optimal analytical instruments.3 The organic liquid used should be of the same organic composition as that adsorbed on the carbon sample.
SCOPE
1.1 This guide covers the measurement of the temperature rise resulting from the heat of immersion when a known mass of a specified organic liquid is added to a sample of activated carbon. If the carbon has been in use as an adsorbent and may therefore be partially or fully exhausted, its degree of saturation may be estimated by comparing its temperature rise with that of an unused sample of the same activated carbon.  
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.  
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: 07.030 - Physics. Chemistry
• Technical Committee: D28 - Activated Carbon
• Drafting Committee: D28.04 - Gas Phase Evaluation Tests

Relations

• Refers: ASTM D2854-09(2014) - Standard Test Method for Apparent Density of Activated Carbon
• Effective Date: 01-Jul-2014
• Refers: ASTM D2652-11 - Standard Terminology Relating to Activated Carbon
• Effective Date: 15-Jun-2011
• Refers: ASTM D2854-09 - Standard Test Method for Apparent Density of Activated Carbon
• Effective Date: 01-Apr-2009
• Refers: ASTM D2652-05a - Standard Terminology Relating to Activated Carbon
• Effective Date: 01-Jul-2005
• Refers: ASTM D2652-05 - Standard Terminology Relating to Activated Carbon
• Effective Date: 01-Jun-2005
• Refers: ASTM D2854-96(2004) - Standard Test Method for Apparent Density of Activated Carbon
• Effective Date: 01-Oct-2004
• Refers: ASTM D2854-96(2000) - Standard Test Method for Apparent Density of Activated Carbon
• Effective Date: 01-Jan-2000
• Refers: ASTM D2652-94(1999) - Standard Terminology Relating to Activated Carbon
• Effective Date: 10-Feb-1999

Overview

ASTM D7385-21: Standard Guide for Estimating Carbon Saturation by Temperature Rise Upon Immersion sets forth a practical method for rapidly estimating the degree of saturation in used activated carbon. This standard is designed for field use, especially when immediate results are needed and advanced laboratory equipment is not available. By measuring the heat generated when a known organic liquid is added to a sample of activated carbon, users can compare temperature changes against those from unused carbon to estimate remaining adsorptive life.

This guide supports decisions about maintenance, replacement, and management of activated carbon in a variety of industrial and environmental applications. Measurements and evaluations defined by this standard are to be carried out using SI units only.

Key Topics

• Activated carbon saturation: The method allows for estimating the remaining adsorptive capacity and hence the service life of activated carbon that has been put into use.
• Field-friendly testing: The procedure is specifically formulated to be practical for rapid, in situ assessments without advanced analytical instruments.
• Temperature rise method: The degree of saturation is deduced by observing the difference in temperature increase upon immersion of both used and unused activated carbon samples in a suitable organic liquid.
• Organic liquid selection: The chosen organic liquid must closely match the compounds previously adsorbed by the carbon, helping to minimize error and ensuring reliable results.
• Apparatus and safety: Simple apparatus such as non-mercury thermometers and common containers are used, with guidelines for safe and environmentally responsible practice.

Applications

ASTM D7385-21 is especially valuable in sectors that rely on activated carbon for purification or filtration, including:

• Water and air treatment: Monitor adsorption efficiency and plan for timely carbon replacement in municipal and industrial treatment systems.
• Environmental services: Rapidly evaluate carbon saturation at remediation sites and in mobile field operations.
• Chemical and process industries: Assess the performance of activated carbon in adsorbers for solvents, gases, or hydrocarbon streams.
• Quality assurance: Support procurement and inventory management by comparing new batches and used materials for quality consistency.

This guide helps organizations maximize the effectiveness and service life of activated carbon, enabling data-driven decision-making for operational continuity and cost savings.

Related Standards

ASTM D7385-21 is best used in conjunction with other ASTM standards for activated carbon characterization and handling:

• ASTM D2652 - Terminology Relating to Activated Carbon
• ASTM D2854 - Test Method for Apparent Density of Activated Carbon
• ASTM D2867 - Test Methods for Moisture in Activated Carbon
• ASTM E300 - Practice for Sampling Industrial Chemicals

These standards provide essential definitions and complementary test methods that enhance the accuracy and reproducibility of the carbon saturation assessment.

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Keywords: ASTM D7385-21, activated carbon saturation, temperature rise, adsorptive capacity, field testing, carbon service life, water treatment, air filtration, standard guide, carbon adsorptive capacity, spent activated carbon, industrial standards

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: D7385 − 21
Standard Guide for
Estimating Carbon Saturation by Temperature Rise Upon
Immersion
This standard is issued under the fixed designation D7385; 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 4. Summary of Guide
1.1 This guide covers the measurement of the temperature 4.1 A measured volume of activated carbon is added to a
rise resulting from the heat of immersion when a known mass known volume of a selected organic liquid in a container
of a specified organic liquid is added to a sample of activated provided with means to measure the liquid temperature. The
carbon. If the carbon has been in use as an adsorbent and may apparatus is sealed after the addition of the carbon and the
therefore be partially or fully exhausted, its degree of satura- maximum rise in temperature is recorded. The degree of
tion may be estimated by comparing its temperature rise with saturation of a used carbon is estimated by comparing its
that of an unused sample of the same activated carbon. temperature rise with that of the original unused activated
carbon of equivalent moisture content, measured under the
1.2 The values stated in SI units are to be regarded as
same conditions. If no such reference sample is available, a
standard. No other units of measurement are included in this
commercial unused activated carbon of the same physical type
standard.
from a reputable manufacturer may be substituted; such
1.3 This standard does not purport to address all of the
substitution should be noted in the report.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety, health, and environmental practices and deter-
5.1 Itisoftenusefultoestimatethedegreeofsaturation,and
mine the applicability of regulatory limitations prior to use.
hence the expected remaining service life, of activated carbon
1.4 This international standard was developed in accor-
that has been in use for some time. This guide is applicable
dance with internationally recognized principles on standard-
when such information must be obtained fairly rapidly under
ization established in the Decision on Principles for the
field conditions without access to optimal analytical instru-
Development of International Standards, Guides and Recom-
ments. The organic liquid used should be of the same organic
mendations issued by the World Trade Organization Technical
composition as that adsorbed on the carbon sample.
Barriers to Trade (TBT) Committee.
6. Apparatus and Materials
2. Referenced Documents
6.1 Apparatus—The apparatus should consist of a container
2.1 ASTM Standards:
such as a small bottle or flask to accommodate the carbon, the
D2652 Terminology Relating to Activated Carbon
organic liquid, and a thermometer or thermocouple with a
D2854 Test Method for Apparent Density of Activated
range to allow for a temperature rise of up to about 30 °C,
Carbon
graduated in intervals of 0.5 °C, with facility to interpolate to
60.1 °C. A liquid-in-glass thermometer should not use mer-
3. Terminology
cury because of the greater risk of breakage under field
3.1 Terms related to this guide are defined in Terminology
conditions. The container should be provided with a rubber
D2652.
stopper or other suitable closure to seal the contents after the
carbon has been added to the organic liquid. Appropriate
containers include an Erlenmeyer or Florence flask of about
This guide is under the jurisdiction of ASTM Committee D28 on Activated
125 to 250 mL capacity or a similar-sized narrow-necked
Carbon and is the direct responsibility of Subcommittee D28.04 on Gas Phase
Evaluation Tests. bottle.
Current edition approved June 1, 2021. Published June 2021. Originally
6.2 Materials—Many organic liquids that are insoluble in
approved in 2007. Last previous edition approved in 2013 as D7385 – 13. DOI:
10.1520/D7385-21. water but readily soluble in other adsorbates that may already
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Stone, H. W. and Clinton, R. O., Ind. Eng. Chem., Anal. Ed., Vol 14, 1942,
the ASTM website
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7385 − 13 D7385 − 21
Standard Guide for
Estimating Carbon Saturation by Temperature Rise
uponUpon Immersion
This standard is issued under the fixed designation D7385; 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
1.1 This guide covers the measurement of the temperature rise resulting from the heat of immersion when a known mass of a
specified organic liquid is added to a sample of activated carbon. If the carbon has been in use as an adsorbent and may therefore
be partially or fully exhausted, its degree of saturation may be estimated by comparing its temperature rise with that of an unused
sample of the same activated carbon.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
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.
2. Referenced Documents
2.1 ASTM Standards:
D2652 Terminology Relating to Activated Carbon
D2854 Test Method for Apparent Density of Activated Carbon
D2867 Test Methods for Moisture in Activated Carbon
E300 Practice for Sampling Industrial Chemicals
3. Terminology
3.1 Terms related to this guide are defined in Terminology D2652.
4. Summary of Guide
4.1 A measured volume of activated carbon is added to a known volume of a selected organic liquid in a container provided with
means to measure the liquid temperature. The apparatus is sealed after the addition of the carbon and the maximum rise in
This guide is under the jurisdiction of ASTM Committee D28 on Activated Carbon and is the direct responsibility of Subcommittee D28.04 on Gas Phase Evaluation
Tests.
Current edition approved Sept. 1, 2013June 1, 2021. Published September 2013June 2021. Originally approved in 2007. Last previous edition approved in 20072013 as
D7385 – 07.13. DOI: 10.1520/D7385-13.10.1520/D7385-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7385 − 21
temperature is recorded. The degree of saturation of a used carbon is estimated by comparing its temperature rise with that of the
original unused activated carbon of equivalent moisture content, measured under the same conditions. If no such reference sample
is available, a commercial unused activated carbon of the same physical type from a reputable manufacturer may be substituted;
such substitution should be noted in the report.
5. Significance and Use
5.1 It is often useful to estimate the degree of saturation, and hence the expected remaining service life, of activated carbon that
has been in use for some time. This guide is applicable when such information must be obtained fairly rapidly under field
conditions without access to optimal analytical instruments. The organic liquid used should be of the same organic composition
as that adsorbed on the carbon sample.
6. Apparatus and Materials
6.1 Apparatus—The apparatus should consist of a container such as a small bottle or flask to accommodate the carbon, the organic
liquid, and a thermometer or thermocouple with a range to allow for a temperature rise of up to about 30 ºC,30 °C, graduated in
intervals of 0.5 ºC,0.5 °C, with facility to interpolate to 60.1 ºC.60.1 °C. A liquid-in-glass thermometer should not use
mercury,mercury because of the greater risk of breakage under field conditions. The container should be provided with a rubber
stopper or other suitable closure to seal the contents after the carbon has been added to the organic liquid. Appropriate containers
include an Erlenmeyer or Florence flask of about 125 to 250 mL capacity or a similar-sized narrow-necked bottle.
6.2 Materials—Many organic liq
...