ASTM D6851-02(2011)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D6851 − 02 (Reapproved 2011)
Standard Test Method for
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 electrodes can be found which have a detachable junction
allowing the user when necessary to discard a fouled pH
1.1 This method is to be used in the determination of the pH
membrane.
of water on initial contact with activated carbon. This test
method is not meant as a replacement for Test Method D3838 5.2 Distilled water can become acidic on standing. Make
and may give a different value. sure that the water used meets the minimum requirements for
ASTM Type II water. Determine the pH as indicated in Test
1.2 This standard does not purport to address all of the
Method D1293.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
6. Apparatus
priate safety and health practices and to determine the
6.1 A pH meter (ambient temperature of 25 °C is assumed;
applicability of regulatory limitations prior to use.
ifotherwise,temperaturecompensationisrequiredforaccurate
pH measurement.
2. Referenced Documents
6.2 A combination pH electrode, or glass-calomel elec-
2.1 ASTM Standards:
trodes used together.
D1193 Specification for Reagent Water
D1293 Test Methods for pH of Water
6.3 A100 mL (TD) graduated cylinder
D3838 Test Method for pH of Activated Carbon
6.4 A250 mL glass beaker (for each sample)
E300 Practice for Sampling Industrial Chemicals
6.5 A polymer-coated magnetic stir bar (for each sample)
3. Summary of Test Method
6.6 Magnetic stir plate
3.1 A sample of carbon is stirred with water and the pH of
6.7 A balance capable of accurately measuring to 0.1 g
the suspension is measured.
7. Reagents and Materials
4. Significance and Use
7.1 Distilled or de-ionized water that meets theASTM Type
4.1 ThedeterminationofcontactpHcanbeusedasasimple
II requirements
and fast measurement that can allow activated carbon produc-
7.2 Buffers to calibrate the pH meter; typically pH 4.0, pH
ers and users to have a standard method for assessing the effect
7.0, and/or pH 10.0
various carbons will have on the initial pH of the water in
contact with the carbon. It has been determined that there is a
8. Hazards
bias between this method andTest Method D3838; they are not
8.1 The water in contact with the carbon may have either a
equivalent.
low or high pH. Take precautions accordingly and wear
5. Interferences necessary protective equipment to prevent injuries from spills
and splashes.
5.1 pH electrodes used to measure this quantity can even-
tually become clogged over time with carbon fines. Suitable
9. Sampling, Test Specimens, and Test Units
9.1 Follow Practice E300 in the collection and preparation
This specification is under the jurisdiction of ASTM Committee D28 on
of samples.
ActivatedCarbonandisthedirectresponsibilityofSubcommitteeD28.02onLiquid
Phase Evaluation.
10. Preparation of Apparatus
Current edition approved Sept. 1, 2011. Published November 2011. Originally
approved in 2002. Last previous edition approved in 2007 as D6851 – 02 (2007). 10.1 Use the procedure of T
...