ASTM D6647-01
(Test Method)Standard Test Method for Determination of Acid Soluble Iron Via Atomic Absorption
Standard Test Method for Determination of Acid Soluble Iron Via Atomic Absorption
SCOPE
1.1 This test method covers the determination of the acid soluble iron content of granular and powdered activated carbons, using an atomic absorption spectroscopy method by direct aspiration. Hydrochloric acid is used to extract the iron. This test method is not directly usable to determine the total iron concentration of a sample.
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 determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 8.
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Designation:D6647–01
Standard Test Method for
Determination of Acid Soluble Iron Via Atomic Absorption
This standard is issued under the fixed designation D 6647; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope tor, and onto a detector that measures the amount of light
absorbed by the atomized element in the flame. Because each
1.1 This test method covers the determination of the acid
metal has its own characteristic absorption wavelength, a
soluble iron content of granular and powdered activated
source lamp of that element is used. The amount of energy at
carbons, using an atomic absorption spectroscopy method by
the characteristic wavelength absorbed in the flame is propor-
direct aspiration. Hydrochloric acid is used to extract the iron.
tional to the concentration of the element in the sample over a
This test method is not directly usable to determine the total
limited concentration range.
iron concentration of a sample.
1.2 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
4.1 Arepresentativesampleofthematerialtobeanalyzedis
responsibility of the user of this standard to establish appro-
collected according to E 300.Aknown weight of the sample is
priate safety and health practices and determine the applica-
ground until 95 % or more of the sample passes 325 mesh.The
bility of regulatory limitations prior to use. For a specific
ground sample is oven dried, and then mixed with a dilute
hazard statement, see Section 8.
hydrochloric acid. The solution is boiled for 5 minutes to
2. Referenced Documents convert the iron into a soluble chloride, and then cooled and
filtered. The filter cake is washed with water. Then the filtrate
2.1 ASTM Standards:
2 is transferred quantitatively to a beaker. The concentration of
D 2652 Terminology Relating to Activated Carbon
iron in the filtrate is measured by atomic absorption against a
D 1193 Specification for Reagent Water
set of standards. The acid soluble iron concentration is then
E 11 Specification for Wire-Cloth Sieves for Testing Pur-
calculated against the weight of the original sample.
poses
E 177 Practice for Use of the Terms Precision and Bias in
5. Significance and Use
ASTM Test Methods
5.1 In certain applications, such as acid purification, acidic
E 287 SpecificationforLaboratoryGlassGraduatedBurets
food or chemical purification or decolorization, or other
E 288 Specification for Laboratory Glass Volumetric
applicationswhereinironmaybeleachedoutofthecarbon,the
Flasks
5 use of acid-washed carbons will reduce or eliminate color
E 300 Practice for Sampling Industrial Chemicals
pickup in the effluent or in the product. The acid soluble iron
2.2 NIST Publication:
6 content is usually specified by the carbon supplier to prevent
Circular 602 Testing of Glass Volumetric Apparatus
unacceptable levels of iron leach occurring.
3. Terminology 5.2 Detection limits, sensitivity, and optimum ranges will
vary with the models of atomic absorption spectrophotometers.
3.1 Definitions—Terms relating to this standard are defined
General instrumental parameters are as follows:
in Terminology D 2652.
5.2.1 Iron hollow cathode lamp.
3.1.1 atomic absorption—in flame atomic absorption spec-
5.2.2 Wavelength: 248.3 nm.
trometry, a sample is aspirated into a flame and atomized. A
5.2.3 Fuel: acetylene (high purity).
light beam is directed through the flame, into a monochroma-
5.2.4 Oxidant: air (from compressed air line, laboratory
compressor, or a cylinder of compressed air—all need to be
This test method is under the jurisdiction of ASTM Committee D28 on
clean and dry).
ActivatedCarbonandisthedirectresponsibilityofSubcommitteeD28.02onLiquid
5.2.5 Type of flame: oxidizing.
Phase Evaluation.
5.2.6 The following lines may also be used:
Current edition approved April 10, 2001. Published May 2001.
Annual Book of ASTM Standards, Vol 15.01. 248.8 nm Relative Sensitivity 2
Annual Book of ASTM Standards, Vol 11.01. 271.9 nm Relative Sensitivity 4
302.1 nm Relative Sensitivity 5
Annual Book of ASTM Standards, Vol 14.02.
252.7 nm Relative Sensitivity 6
Annual Book of ASTM Standards, Vol 15.05.
Available from National Institute of Standards and Technology, U.S. Depart-
ment of Commerce, Gaithersburg, MD, 20899.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6647
7.4 Standard Iron Solution II—Pipette100.0ml.ofstandard
372.0 nm Relative Sensitivity
iron solution I into a one liter volumetric flask. Dilute to the
mark with water. Mix thoroughly. This solution contains 0.01
5.3 The method, as written, is intended for carbons having
mg. of iron/ml.
an acid soluble iron content of 0.0030 to 0.050 % For carbons
having higher iron contents, larger dilutions or smaller aliquots
NOTE 2—Commercially available iron solutions obtained from chemi-
may be used. calsupplyhouseshavebeenfoundtobeacceptable,providedtheaccuracy
of the solution meets specified requirements.
5.4 The user should validate that there are no interferences
from other metals in the sample matrix.
8. Hazards
5.5 To prevent erroneous results, the user should ensure that
8.1 Severalpotentialhazardsareassociatedwithconducting
no iron instruments contact any of the sample or the solutions
this test procedure. It is not the purpose of this standard to
used in this procedure. Only glass, ceramics, or plastic should
address all potential health and safety hazards associated with
be allowed to contact the sample or solutions.
its use. The user is responsible for establishing appropriate
healthandsafetypracticesandtodeterminetheapplicabilityof
6. Apparatus
any federal and state regulations before attempting to use this
6.1 Atomic absorption spectrometer, consisting of a light
test method.
source emitting the line spectrum of an element (see 5.2.1
8.1.1 Since this procedure involves the use of hydrochloric
above), a device for vaporizing the sample (usually a flame), a
acid, all necessary personal protective equipment for handling
means for isolating an absorption line (monochromator or filter
acids should be used, including rubber gloves, lab apron, and
and adjustable slit—see 5.2.2 and 5.2.6 above), and a photo-
goggles. Careful handling and good laboratory technique
electric detector with its associated electronic amplifying and
should always be used when working with chemicals. Avoid
measuring equipment.
contact with hydrochloric acid or acid vapor. Care should be
6.2 Beakers—Griffen, low form, 400 ml., Pyrex or equiva- taken to prevent burns during handling of various solutions
lent. during this test procedure.
8.1.2 The atomic absorption spectrometer should be vented
6.3 Cylinder—ASTM, graduated, 100 ml.
appropriately as recommended by the instrument manufacturer
6.4 Flask—Filtering, with side tube, 250 ml.
to dissipate fumes and vapors generated by the combustion the
6.5 Buchner Funnel—Size D, 71 mm. ID.
flame.Thisprecautionprotectslaboratorypersonnelfromtoxic
6.6 Filter Paper—Whatman No. 3, 7.0 cm. or equivalent.
vapors, protects the instrument from corrosive vapors, and
6.7 Flasks—Volumetric, 50, 100. 250, 500, and 1000 ml.
prevents flame stability from being affected by room drafts.
6.8 Pipettes—Volumetric, 1,2,5,10,25, and 100 ml.
8.1.3 The user of this test should comply with all federal,
6.9 325 Mesh Screen (U.S. Sieve series).
state, and local regulations for safe disposal of all samples and
6.10 Analytical Balance, accuracy plus or minus 0.0001 g.
reagents used.
6.11 Hot Plate.
9. Sampling
NOTE 1—All volumetric measuring eq
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