ASTM D6851-20

Standard Test Method for Determination of Contact pH with Activated Carbon

SIGNIFICANCE AND USE
4.1 The determination of contact pH can be used as a simple and fast measurement that can allow activated carbon producers and users to have a standard method for assessing the effect various carbons will have on the initial pH of the water in contact with the carbon. It has been determined that there is a bias between this method and Test Method D3838; they are not equivalent.
SCOPE
1.1 This method is to be used in the determination of the pH of water on initial contact with activated carbon. This test method is not meant as a replacement for Test Method D3838 and may give a different value.  
1.2 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.  
1.3 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: 14-Jan-2020
• ICS: 71.040.30 - Chemical reagents
• Technical Committee: D28 - Activated Carbon
• Drafting Committee: D28.02 - Liquid Phase Evaluation

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: D6851 − 20
Standard Test Method for
1
Determination of Contact pH with Activated Carbon
This standard is issued under the fixed designation D6851; 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 ers and users to have a standard method for assessing the effect
various carbons will have on the initial pH of the water in
1.1 This method is to be used in the determination of the pH
contact with the carbon. It has been determined that there is a
of water on initial contact with activated carbon. This test
bias between this method andTest Method D3838; they are not
method is not meant as a replacement for Test Method D3838
equivalent.
and may give a different value.
1.2 This standard does not purport to address all of the
5. Interferences
safety concerns, if any, associated with its use. It is the
5.1 pH electrodes used to measure this quantity can even-
responsibility of the user of this standard to establish appro-
tually become clogged over time with carbon fines. Suitable
priate safety, health, and environmental practices and deter-
electrodes can be found which have a detachable junction
mine the applicability of regulatory limitations prior to use.
allowing the user, when necessary, to discard a fouled pH
1.3 This international standard was developed in accor-
membrane.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
5.2 Distilled water can become acidic on standing. Make
Development of International Standards, Guides and Recom-
sure that the water used meets the minimum requirements for
mendations issued by the World Trade Organization Technical
ASTM Type II water. Determine the pH as indicated in Test
Barriers to Trade (TBT) Committee.
Methods D1293.
2. Referenced Documents
6. Apparatus
2
2.1 ASTM Standards:
6.1 A pH meter (ambient temperature of 25 °C is assumed;
D1293 Test Methods for pH of Water
if otherwise, temperature compensation is required for accurate
D3838 Test Method for pH of Activated Carbon
pH measurement).
E177 Practice for Use of the Terms Precision and Bias in
6.2 A combination pH electrode, or glass-calomel elec-
ASTM Test Methods
trodes used together.
E300 Practice for Sampling Industrial Chemicals
E691 Practice for Conducting an Interlaboratory Study to
6.3 A 100-mL (TD) graduated cylinder.
Determine the Precision of a Test Method
6.4 A 250-mL glass beaker (for each sample).
3. Summary of Test Method
6.5 A polymer-coated magnetic stir bar (for each sample).
3.1 A sample of carbon is stirred with water and the pH of
6.6 Magnetic stir plate.
the suspension is measured.
6.7 A balance capable of accurately measuring to 0.1 g.
4. Significance and Use
7. Reagents and Materials
4.1 The determination of contact pH can be used as a simple
7.1 Distilled or de-ionized water that meets theASTM Type
and fast measurement that can allow activated carbon produc-
II requirements.
7.2 Buffers to calibrate the pH meter; typically pH 4.0, pH
1
This test method is under the jurisdiction of ASTM Committee D28 on
7.0, pH 10.0, or combinations thereof.
ActivatedCarbonandisthedirectresponsibilityofSubcommitteeD28.02onLiquid
Phase Evaluation.
Current edition approved Jan. 15, 2020. Published February 2020. Originally
8. Hazards
approved in 2002. Last previous edition approved in 2011 as D6851 – 02 (2011).
DOI: 10.1520/D6851-20.
8.1 The water in contact with the carbon may have either a
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
low or high pH. Take precautions accordingly and wear
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
necessary protective equipment to prevent injuries from spills
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. and splashes.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D6851 − 20
9. Sampling, Test Specimens, and Test Units determination. Practice E691 was followed for the design and
analysis of the data; the details are given in ASTM Research
9.1 Follow Practice E300 in the collection and preparation
3
Report No. RR:D28-1010.
of samples.
16.1.1 Repeatability (r)—The difference between repetitive
results obtained by the same operator in a given laboratory
10. Preparation of Apparatus
applying the sa
...

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: D6851 − 02 (Reapproved 2011) D6851 − 20
Standard Test Method for
1
Determination of Contact pH with Activated Carbon
This standard is issued under the fixed designation D6851; 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 method is to be used in the determination of the pH of water on initial contact with activated carbon. This test method
is not meant as a replacement for Test Method D3838 and may give a different value.
1.2 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 to determine the applicability of regulatory
limitations prior to use.
1.2 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.
1.3 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
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D1293 Test Methods for pH of Water
D3838 Test Method for pH of Activated Carbon
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E300 Practice for Sampling Industrial Chemicals
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Summary of Test Method
3.1 A sample of carbon is stirred with water and the pH of the suspension is measured.
4. Significance and Use
4.1 The determination of contact pH can be used as a simple and fast measurement that can allow activated carbon producers
and users to have a standard method for assessing the effect various carbons will have on the initial pH of the water in contact with
the carbon. It has been determined that there is a bias between this method and Test Method D3838; they are not equivalent.
5. Interferences
5.1 pH electrodes used to measure this quantity can eventually become clogged over time with carbon fines. Suitable electrodes
can be found which have a detachable junction allowing the user, when necessary, to discard a fouled pH membrane.
5.2 Distilled water can become acidic on standing. Make sure that the water used meets the minimum requirements for ASTM
Type II water. Determine the pH as indicated in Test MethodMethods D1293.
1
This specification test method is under the jurisdiction of ASTM Committee D28 on Activated Carbon and is the direct responsibility of Subcommittee D28.02 on Liquid
Phase Evaluation.
Current edition approved Sept. 1, 2011Jan. 15, 2020. Published November 2011February 2020. Originally approved in 2002. Last previous edition approved in 20072011
as D6851 – 02 (2011). (2007). DOI: 10.1520/D6851-02R11.10.1520/D6851-20.
2
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
1

---------------------- Page: 1 ----------------------
D6851 − 20
6. Apparatus
6.1 A pH meter (ambient temperature of 25 °C is assumed; if otherwise, temperature compensation is required for accurate pH
measurement.measurement).
6.2 A combination pH electrode, or glass-calomel electrodes used together.
6.3 A100 mLA 100-mL (TD) graduated cylindercylinder.
6.4 A250 mLA 250-mL glass beaker (for each sample)sample).
6.5 A polymer-coated magnetic stir bar (for each sample)sample).
6.6 Magnetic stir plateplate.
6.7 A balance capable of accurately measuring to 0.1 gg.
7. Reagents and Materials
7.1 Distilled or de-ionized water that meets the ASTM Type II requirementsrequirements.
7.2 Buffers to calibrate the pH meter; typically pH 4.0, pH 7.0, and/or pH 10.0pH 10.0, or combinations there
...