ASTM D5919-96(2022)

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: D5919 − 96 (Reapproved 2022)
Standard Practice for
Determination of Adsorptive Capacity of Activated Carbon
by a Micro-Isotherm Technique for Adsorbates at ppb
Concentrations
This standard is issued under the fixed designation D5919; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1193Specification for Reagent Water
D2652Terminology Relating to Activated Carbon
1.1 This practice covers the assessment of activated carbon
D2867Test Methods for Moisture in Activated Carbon
for the removal of low concentrations of adsorbable constitu-
D3370Practices for Sampling Water from Flowing Process
entsfromwaterandwastewaterusingthebottlepointisotherm
Streams
technique. It can be used to characterize the adsorptive
properties of virgin and reactivated activated carbons.
3. Terminology
1.2 This practice can be used in systems with constituent
3.1 Definitions:
concentrations in the low milligrams per litre or micrograms
3.1.1 Fordefinitionsoftermsusedinthispracticerelatingto
per litre concentration ranges.
activated carbon, refer to Terminology D2652.
1.3 This practice can be used to determine the adsorptive
3.1.2 Fordefinitionsoftermsusedinthispracticerelatingto
capacity of and Freundlich constants for volatile organic
water, refer to Terminology D1129.
compounds provided the handling procedures described in this
practice are followed carefully.
4. Summary of Practice
1.4 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 4.1 This practice consists of the determination of the ad-
standard.
sorptive capacity of activated carbon for adsorbable constitu-
ents by contacting the aqueous solution contained in an
1.5 This standard does not purport to address all of the
essentially zero headspace container with activated carbon,
safety concerns, if any, associated with its use. It is the
determining the amount of the constituents removed, and
responsibility of the user of this standard to establish appro-
calculating the adsorptive capacity and the Freundlich
priate safety, health, and environmental practices and deter-
constants, K and 1/n, from a Freundlich isotherm plot.
mine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accor- 4.1.1 The weights of activated carbon used in this practice
dance with internationally recognized principles on standard-
may have to be adjusted to achieve reasonable levels of
ization established in the Decision on Principles for the removal of the constituent. The best data is obtained when
Development of International Standards, Guides and Recom-
carbondosagesareselectedthatresultinnomorethan90%or
mendations issued by the World Trade Organization Technical nolessthan10%oftheadsorbableconstituentsbeingremoved
Barriers to Trade (TBT) Committee.
from the water by the carbon.
4.1.2 If carbon dosages used are less than 1 mg, larger
2. Referenced Documents
volumes of the aqueous solution may be used, such as
2.1 ASTM Standards:
1000mL.
D1129Terminology Relating to Water
5. Significance and Use
This practice is under the jurisdiction of ASTM Committee D28 on Activated
Carbon and is the direct responsibility of Subcommittee D28.02 on Liquid Phase
5.1 This practice allows the adsorption capacity at equilib-
Evaluation.
riumofanactivatedcarbonforadsorbableconstituentspresent
Current edition approved Sept. 1, 2022. Published October 2022. Originally
in water to be determined.The Freundlich K and 1/n constants
approved in 1996. Last previous edition approved in 2017 as D5919–96 (2017).
DOI: 10.1520/D5919-96R22.
that can be calculated based upon information collected using
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
this practice can be used to estimate carbon loading capacities
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
andusagesratesfortheconstituentpresentinawaterstreamat
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. other concentrations.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5919 − 96 (2022)
6. Interferences pollutantanalysis,hotwateranddetergentwash,reagentgrade
water, and solvent (high purity methanol) rinse followed by a
6.1 The water shall not contain any nondissolved compo-
bake-out.
nents.
9.3 The glassware is baked out in an oven at 250°C for a
6.2 The presence of naturally occurring organic compounds
minimum of one hour. All PTFE and stainless steel apparatus
such as humic acids in the water being studied may signifi-
are dried at 110°C for one hour.
cantly affect the ability of the carbon to adsorb the constituent
of interest. Results obtained when using water other than
10. Preparation of the Activated Carbon
reagent grade water may be unique for the particular water
10.1 This practice requires the use of well washed activated
used and it may not be possible to apply these results to other
carbon that has been reduced in particle size so that 90% or
water systems.
greater passes through a U.S. No. 325-mesh (45-µm) sieve by
6.3 The adsorption isotherm data collected using this prac-
wet screening or equivalent.
tice can be affected by the ionic strength, pH and temperature
10.2 Approximately 25 g of the powdered activated carbon
of the water, and the presence and growth of microorganisms.
sample is placed into each of four clean 250mL bottles. The
remainder of the bottle is filled with reagent grade water.
7. Apparatus
10.3 The bottle is tightly capped and inverted three to five
7.1 Equilibrator(orotherrotatingmixingdevice),arotating
times to mix the contents.
device operating at 25 r/min which can rotate the isotherm
bottles end-over-end, ensuring good dispersion of the pow-
10.4 The bottles are then centrifuged at 2000 r/min for 15
dered activated carbon in the water being treated.
min to settle the activated carbon. The supernate is poured off
and the procedure is repeated until the supernatant is clear.
7.2 Grinding Mill,capableofgrindingmaterialsothat90%
Allowing the mixture to sit for a period of time to allow the
passes through a U.S. No. 325-mesh (45µm) sieve.
carbon to settle prior to decanting is also acceptable.
7.3 Isotherm Bottles, narrow neck amber bottles with poly-
10.5 The wet carbon is next dried in an oven at 110°C to a
tetrafluoroethylene (PTFE)-coated septum sealed caps of 250,
constant weight and placed in a desiccator to cool.
500, and 1000mL capacity suitable for use in a centrifuge
operating at 2000 r/min.
10.6 As an alternate technique to drying the carbon sample,
carbon may be placed in a soxhlet extraction device and
7.4 Solution Delivery Tank, a 10L, 316 stainless steel
extractedforaperiodofupto1weekwithreagentgrade(Type
container equipped with a PTFE-coated floating lid and a 316
II) water.
stainless ball valve to control flow during bottle filling.
10.7 The dry activated carbon is transferred to clean 1L
7.5 Analytical Balance, capable of weighing to the nearest
brown borosilicate bottles with PTFE liners in the caps and
0.1 mg.
stored in an inert atmosphere such as nitrogen for future use.
7.6 Oven, forced-air circulation, capable of temperature
regulation up to 250°C.
11. Activated Carbon Sample Weighing Procedure
7.7 Centrifuge, capable of handling isotherm bottles up to
11.1 This procedure allows the carbon to be handled at
1L in size at 2000 r/min.
ambient conditions by calculating a correction for water
7.8 Magnetic Stirring Bars and Stirrers. adsorbed from the air.
11.2 The powdered activated carbon sample is allowed to
8. Reagents
come to equilibrium in a desiccator containing a saturated salt
8.1 Reagent Water,inaccordancewithSpecificationD1193, solution that will produce a relative humidity comparable to
Type II. ambient laboratory conditions. During the 24-h conditioning
period, care shall be taken not to expose the carbon to organic
8.2 Methanol, high purity HPLC grade.
vapors.
8.3 Potassium Monobasic Phosphate (KHPO4), 1 M solu-
11.3 The moisture picked up by the conditioned activated
tion.
carbon is determined by weighing approximately 500 mg into
8.4 Sodium Hydroxide (NaOH), 1 M solution.
a tared (constant weight) bottle, drying for2hat110°C,
cooling in a desiccator, and re-weighing to determine weight
9. Cleaning Procedures
change(refertoTestMethodsD2867forstandardprocedures).
9.1 This practice is capable of generating activated carbon The ratio of change in weight between the activated carbon at
adsorptioncapacitydataonaqueoussolutionscontainingppbw equilibrium with air and after drying is calculated and used as
(µg/L) levels of adsorbable constituents. It is therefore very a correction factor for the weighed carbon dosages.
important that all equipment and glassware that come in
11.4 The carbon dosages are weighed by first taking a
contact with the activated carbon or the water being treated be
weighing boat, adding the desired mass of equilibrated acti-
cleaned thoroughly to remove trace organic compounds.
vated carbon, and re-weighing the boat after transferring the
9.2 All equipment and glassware should first be rigorously carbon to the bottle. The carbon dosage is the difference
cleanedusingproceduresrecommendedbytheEPAforpriority between the carbon plus the boat weight and the final boat
D5919 − 96 (2022)
weight.The weighed activated carbon dosage is then corrected 14.2 The preparation of a laboratory solution requires the
for ambient conditions and the actual dried carbon dosage use of a 10L, 316 stainless steel delivery container equipped
recorded. with a floating cover and flow control ball valve.
14.3 If reagent grade water is to be used, it may be buffered
12. Alternative Procedure for Addition of Known
toavoidpHeffectsontheadsorptionoftheorganicconstituent.
Quantities of Activated Carbon to Isotherm Bottles
The buffer is prepared by adding 1 mL of a 1 M potassium
12.1 This alternat
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