ASTM D4548-91(1996)

Designation: D 4548 – 91 (Reapproved 1996)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Anion-Cation Balance of Mixed Bed Ion-Exchange Resins
This standard is issued under the fixed designation D 4548; 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 3.2.6 salt-splitting, adj—the ability of anion-exchange or
cation-exchange materials to exchange hydroxide or hydrogen
1.1 This test method determines the ratio between the
ions respectively for the ions in neutral salts.
equivalents of anion-exchange capacity and the equivalents of
cation-exchange capacity present in a physical mixture of
4. Summary of Test Method
salt-splitting anion-exchange material and salt-splitting cation-
4.1 This test method consists of simultaneous conversion of
exchange material.
the cation-exchange component to the hydrogen form and the
1.2 The values stated in SI units are to be regarded as the
anion-exchange component to the chloride form with hydro-
standard.
chloric acid. After rinsing to remove the excess acid, the
1.3 This standard does not purport to address all of the
hydrogen ion from the cation resin and the chloride ion from
safety concerns, if any, associated with its use. It is the
the anion resin are simultaneously eluted with neutral sodium
responsibility of the user of this standard to establish appro-
nitrate, and the amount eluted is determined by titration of the
priate safety and health practices and determine the applica-
effluent for both ions.
bility of regulatory limitations prior to use.
2. Referenced Documents 5. Significance and Use
2.1 ASTM Standards: 5.1 This test method is applicable to the analysis of new
D 1129 Terminology Relating to Water materials that are sold as mixtures and to samples taken from
D 1193 Specification for Reagent Water regenerable units containing mixtures of anion-exchanging and
D 2187 Test Methods for Physical and Chemical Properties
cation-exchanging materials. It is used to determine the ratio of
of Particulate Ion-Exchange Resins the components without separating them from each other.
5.2 This test method is intended for mixtures of ion-
3. Terminology
exchange materials that have salt-splitting capacity as mea-
3.1 Definitions—For definitions of terms used in this test
sured by Test Method E of Test Methods D 2187 for cation-
method, refer to Terminology D 1129.
exchange resins, and Test Method H for anion-exchange resins.
3.2 Definitions of Terms Specific to This Standard:
In the case of cation-exchange resins, these are styrene-based
3.2.1 anion-exchange material, n—an ion-exchange mate-
polymers with sulfonic acid functional groups. The anion-
rial capable of the reversible exchange of negatively charged
exchanging materials in this class are styrene-based materials
ions.
with quaternary ammonium functional groups. The test method
3.2.2 cation-exchange material, n—an ion-exchange mate-
will determine the amount of anion-exchange material of any
rial capable of the reversible exchange of positively charged
functionality present in the mixture. However, when anionic
ions.
groups that are not salt-splitting are present, the values for
3.2.3 ion-exchange material, n—an insoluble material that
cationic groups will be high due to the acidic character of the
has the ability to exchange reversibly certain ions in its
anion effluent. Cationic groups that do not split salts are not
structure or attached to its surface as functional groups with
measured.
ions in a surrounding medium.
5.3 Samples are analyzed in this test method as received. It
3.2.4 ion-exchange resin, n—a synthetic organic ion-
is not necessary that the cation-exchanging resin be in the
exchange material.
hydrogen form and the anion-exchanging resin be in the
3.2.5 mixed bed, n—a physical mixture of anion-exchange
hydroxide form for this test method.
material and cation-exchange material.
5.4 This test method may be used to determine if new
materials are balanced to meet their specification values. In
operating regenerable units, it may be used to determine if the
This test method is under the jurisdiction of ASTM Committee D-19 on Water
components are separating properly or remixing properly. It
and is the direct responsibility of Subcommittee D19.08 on Membranes and Ion
Exchange Materials.
may also be used to check for improper balance in bedding or
Current edition approved June 15, 1991. Published February 1992. Originally
for loss of a component during operation.
published as D 4548 – 86. Last previous edition D 4548 – 86.
5.5 This test method begins with the conversion to the
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 11.02. hydrogen and chloride forms. However, it may be combined
D 4548
7.7 Nitric Acid (1 + 9)—Pour 1 vol of nitric acid (sp gr 1.42)
into 9 vol of water and mix thoroughly.
7.8 Phenolphthalein Indicator Solution (5.0 g/L)—Dissolve
0.5 g of phenolphthalein in 50 mL of 95 % ethanol (see Note
1). Transfer to a volumetric flask and dilute to 100 mL with
water.
NOTE 1—Isopropyl alcohol or specially denatured ethyl alcohol con-
forming to Formula 3A or 30 of the US Bureau of Internal Revenue may
be substituted for 95 % alcohol.
7.9 Potassium Chromate Solution (50 g/L)—Dissolve 5.0 g
of potassium chromate in 50 mL of water. Dilute to 100 mL
with water.
7.10 Silver Nitrate Solution, Standard (0.10 N)—Dry crys-
talline silver nitrate at 105°C for 1 h and cool in a desiccator.
Weigh out 176 0.05 g of AgNO . Transfer to a 1-L volumetric
FIG. 1 Typical Arrangement of Apparatus for Salt-Splitting
flask with water. Dissolve in 500 mL of water. Dilute to 1-L
Capacity
with water at 25 6 5°C and mix well. Store the solution in a
tightly stoppered amber glass bottle.
with the determination of the residual chloride and sulfate sites
7.10.1 To standardize, dry approximately5gof sodium
by elution with sodium nitrate as described in Test Methods J
chloride in a glass container at 105°C for 2 h. Cool in a
and L in Test Methods D 2187. In such cases the hydrogen ion
desiccator. Weigh accurately three 0.25 6 0.01 g portions of
as well as the chloride ion is determined in the second sodium
the dried NaCl and transfer to separate 250 mL conical flasks.
nitrate elution described in Test Method I of Test Methods
Add 100 mL of water and dissolve the NaCl. Add 1 mL of
D 2187, and the calculations given herein are made using the
K CrO solution (50 g/L) and titrate with the 0.1 N AgNO
2 4 3
titration values so determined.
standard solution with vigorous swirling until the color change
6. Apparatus
of the solution from yellow to red-orange persists for 30 s.
6.1 Test Apparatus, as shown in Fig. 1, shall consist of a 7.10.2 Calculate the normality of the AgNO standard
solution as follows:
filter tube of at least 30 mL in capacity having a diameter of at
least 20 mm, containing a sintered glass plate of coarse (A)
N 5 A/~0.05845 3 B!
s
porosity, a 1-L separatory funnel, and a 1-L volumetric flask.
where:
7. Reagents and Materials
N 5 normality of the AgNO standard solution,
s 3
A 5 actual grams of NaCl used, and
7.1 Purity of Reagents—Reagent grade chemicals shall be
B 5 AgNO standard solution required for the titration,
used in all tests. Unless otherwise indicated, it is intended tha
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