ASTM D1782-95(2001)
(Test Method)Standard Test Methods for Operating Performance of Particulate Cation-Exchange Materials
Standard Test Methods for Operating Performance of Particulate Cation-Exchange Materials
SIGNIFICANCE AND USE
Cation exchange materials are frequently used in the sodium form to exchange divalent and trivalent ions in the influent water for sodium ions on the resin sites. This process is commonly referred to as softening water since it removes those ions that form a “hard” curd of insoluble salts with the fatty acids used in some soaps and that also precipitate when water is boiled. In such a process, sodium chloride is used as the regenerant to return the cation-exchanging groups to the sodium form.
This test method is intended to simulate the performance of such materials in actual usage. It may be used either to compare the performance of new materials or to compare the performance of a material that has been used with its original performance.
Regenerant concentrations and dosages used herein are typical for the types of materials used in this application. If different concentrations or amounts of regenerant are agreed upon by parties using this test method, this fact should be stated when the results are reported. Similarly, the test water specified is the agreed upon standard. Where other test waters or the water to be treated are used in the test, the analysis of the water in terms of total solids, sodium, calcium, magnesium, other di- or trivalent metals as well as the major anions present should be reported with the test results.
SCOPE
1.1 These test methods cover the determination of the operating capacity of particulate cation-exchange materials when used for the removal of calcium, magnesium, and sodium ions from water. It is intended for use in testing both new and used materials. The following two test methods are included: SectionsTest Method A-Sodium Cycle8 to 14Test Method B-Hydrogen Cycle15 to 21
1.2 The values given in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.
1.3 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.
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Designation:D 1782–95 (Reapproved 2001)
Standard Test Methods for
Operating Performance of Particulate Cation-Exchange
Materials
This standard is issued under the fixed designation D 1782; 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 3.2.2 hydrogen cycle—the operation of a cation-exchange
cycle wherein the removal of specified cations from influent
1.1 These test methods cover the determination of the
water is accomplished by exchange with an equivalent amount
operating capacity of particulate cation-exchange materials
of hydrogen ion from the exchange material.
whenusedfortheremovalofcalcium,magnesium,andsodium
3.2.3 theoretical free mineral acidity—the free mineral
ions from water. It is intended for use in testing both new and
acidity that would result from the conversion of the anions of
used materials. The following two test methods are included:
strong acids in solution to their respective free acids.
Sections
Test Method A-Sodium Cycle 8 to 14
4. Summary of Test Methods
Test Method B-Hydrogen Cycle 15 to 21
4.1 Test MethodAconsists of repeated cycles of backwash,
1.2 The values given in SI units are to be regarded as the
brine regeneration, rinse, and exhaustion of the sample in the
standard. The inch-pound units given in parentheses are for
form of a bed in a transparent column.The exhausting medium
information only.
used is an ion-exchange test water.
1.3 This standard does not purport to address all of the
4.2 Test Method B consists of repeated cycles of backwash,
safety concerns, if any, associated with its use. It is the
acid regeneration, rinse, and exhaustion of the sample in the
responsibility of the user of this standard to establish appro-
form of a bed in a transparent column.The exhausting medium
priate safety and health practices and determine the applica-
used is an ion-exchange test water.
bility of regulatory limitations prior to use.
5. Apparatus
2. Referenced Documents
5.1 Test Assemble (see Fig. 1), consisting of the following:
2.1 ASTM Standards:
2 5.1.1 Column, transparent, vertically supported, 25.4 6 2.5
D 1067 Test Methods for Acidity or Alkalinity of Water
mm (1.0 6 0.1 in.) in inside diameter and approximately 1500
D 1126 Test Method for Hardness in Water
2 mm(60in.)long.Thebottomofthecolumnshallbeclosedand
D 1129 Terminology Relating to Water
provided with an outlet of approximately 6-mm inside diam-
D 1193 Specification for Reagent Water
eter. Connections shall be provided at top and bottom for
D 2687 Practices for Sampling Particulate Ion-Exchange
admission and removal of solutions as described in Section 10.
Materials
Adequate means for measuring and regulating flow shall be
3. Terminology
provided. Calibrate the column in such a manner that the
volume readings required by the test method can be made.
3.1 Definitions:
Make all measurements at 25 6 5°C.
3.1.1 For definitions of terms used in these test methods,
5.1.2 Support, for the sample, so designed that the distance
refer to Terminology D 1129.
from the sample to the column outlet is at least 50 mm. A
3.2 Definitions of Terms Specific to This Standard: Certain
suggested supporting bed utilizes quartz, glass beads, or other
terms in these test methods that relate specifically to ion
material 1.5 to 3.5 mm in diameter, insoluble in the reagents
exchange are defined as follows:
used, and retained on a corrosion-resistant screen. However,
3.2.1 free mineral acidity—the quantitative capacity of
other supports such as fritted glass or polyester screens may be
aqueous media to react with hydroxyl ions to pH 4.3.
used at the discretion of the interested parties.
These test methods are under the jurisdiction of ASTM Committee D19 on
6. Reagents
Water and are the direct responsibility of Subcommittee D19.08 on Membranes and
6.1 Purity of Reagents—Reagent grade chemicals shall be
Ion-Exchange Materials.
Current edition approved April 15, 1995. Published June 1995. Originally used in all tests. Unless otherwise indicated, it is intended that
published as D 1782 – 60 T. Last previous edition D 1782 – 91.
all reagents shall conform to the specifications of the Commit-
Annual Book of ASTM Standards, Vol 11.01.
tee onAnalytical Reagents of theAmerican Chemical Society,
Annual Book of ASTM Standards, Vol 11.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 1782–95 (2001)
FIG. 1 Typical Arrangement of Apparatus for Performance Testing of Ion-Exchange Materials
NOTE 1—Where new materials are shipped dry, follow the manufac-
where such specifications are available. Other grades may be
turer’s instructions for preconditioning.
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
TEST METHOD A—SODIUM CYCLE
accuracy of the determination.
6.2 Purity of Water— Unless otherwise indicated, refer-
8. Scope
ences to water shall be understood to mean reagent water,Type
8.1 This test method is designed to simulate operating
IV, conforming to Specification D 1193.
conditions on a sodium cycle used for the removal of calcium
7. Sampling
and magnesium and other divalent ions from water.
7.1 To obtain a representative sample of particulate ion-
exchange material, either from a shipment of new product in
9. Significance and Use
the manufacturer’s original packages or from a bed of used
9.1 Cation exchange materials are frequently used in the
material, refer to Practices D 2687.
sodium form to exchange divalent and trivalent ions in the
7.2 Transfer the laboratory sample to a 2-L beaker and add
influent water for sodium ions on the resin sites. This process
enough water to bring the water level up to that of the
is commonly referred to as softening water since it removes
ion-exchange material and soak for 1 h (see Note 1). Mix the
those ions that form a “hard” curd of insoluble salts with the
sample thoroughly and transfer a sufficient representative
fatty acids used in some soaps and that also precipitate when
portion to fill a 400-mL beaker. Use this portion of sample in
water is boiled. In such a process, sodium chloride is used as
the procedure.
the regenerant to return the cation-exchanging groups to the
sodium form.
9.2 Thistestmethodisintendedtosimulatetheperformance
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
of such materials in actual usage. It may be used either to
listed by the American Chemical Society, see Analar Standards for Laboratory
compare the performance of new materials or to compare the
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
performance of a material that has been used with its original
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
MD. performance.
D 1782–95 (2001)
9.3 Regenerant concentrations and dosages used herein are cloudy (indicating the presence of light, insoluble, extraneous
typical for the types of materials used in this application. If material), adjust the backwash outlet tube to a height above the
different concentrations or amounts of regenerant are agreed bed equal to 75 % of the bed height. Continue backwashing at
upon by parties using this test method, this fact should be the same rate until the effluent is clear.
stated when the results are reported. Similarly, the test water
11.4 Allow the bed to settle and then drain at a rate of
specified is the agreed upon standard. Where other test waters
approximately100mL/minuntilthewaterlevelis20to30mm
or the water to be treated are used in the test, the analysis of the
above the top of the bed. Do not jar. Record the volume, in
water in terms of total solids, sodium, calcium, magnesium,
millilitres, of ion-exchange material. Repeat the 10-min back-
other di- or trivalent metals as well as the major anions present
wash until two successive readings of volume agree within 5
should be reported with the test results.
mL. The average of these two readings shall be the sample
volume for new materials shipped in the sodium form.
10. Reagents and Materials
11.5 Exhaust the ion exchanger with cation-exchange test
10.1 Brine Regenerants:
water A at a flow rate of 0.33 mL/min/mL of exchanger, as
10.1.1 For synthetic organic ion-exchange materials:
measured in 11.4. Maintain a head of liquid not less than 50
10.1.1.1 Sodium Chloride (100 g/L)—Dissolve enough so-
mmabovethetopofthebed.Continuetherununtiltheeffluent
dium chloride (NaCl) in water to make a solution containing in
shows 0.2 meq/L (or other agreed-upon hardness level) when
each litre 100.0 g of NaCl.
tested in accordance with Test Method D 1126. Record the
10.1.2 For all other ion-exchange materials:
volume of test water used.
10.1.2.1 Sodium Chloride (50 g/L)—Dissolve enough NaCl
11.6 Repeat the 10-min backwash and drain as described in
in water to make a solution containing in each litre 50.0 g of
11.3 and 11.4. When testing new material shipped in the
NaCl.
sodium form, only one backwash is necessary at this point
10.2 Cation-Exchange Test Water A (10 meq/L)—Dissolve
because a determination of volume has already been made.
enough calcium chloride (CaCl·2H O) and magnesium sul-
2 2
However, used material other than in the sodium form must
fate (MgSO ·7H O) in water to make a solution containing, in
4 2
have a volume determination made here as described in 11.4.
each litre, 0.49 g of CaCl·2H O and 0.415 g of MgSO ·
2 2 4
Use this sample volume determined on the exhausted material
7H O.Adjust the pH to 7.5 by the addition of Na CO (30 g/L)
2 2 3
in calculating the capacity of used ion-exchange materials.
and determine the hardness of the solution in accordance with
11.7 Determine the amount of brine regenerant and rate
Test Method D 1126. The hardness of the test water will be
required, from Table 1. For use with Table 1, the volume
10.0 6 0.5 meq/L. Use the determined hardness in calculating
sample for new material shall be that determined in accordance
operating capacity as indicated in 12.1. This test water shall be
with 11.4 and for used material shall be that determined in
used for all tests.
accordance with 11.6.
10.3 Hardness Test Reagents—For reagents used in deter-
11.8 Pass the specified volume of brine regenerant through
mining hardness, refer to Test Method D 1126. This reagent is
the bed at the specified rate until only a 20 to 30-mm layer of
used only in preparation of test water (see 10.2).
liquid remains above the bed. Rinse the bed with water, using
10.4 Sodium Carbonate Solution (30 g/L)—Dissolve30gof
the same rate, until one bed-volume of liquid has been
sodium carbonate (Na CO ) in water and dilute to 1 L.
2 3
displaced. Increase the rinse rate to approximately 100 mL/
min. Test for hardness at 3-min intervals by adding 0.5 mL of
11. Procedure
buffer solution to 50 mLof the effluent followed by three drops
11.1 Adjust the temperature of the water and all solutions to
of hardness indicator and 0.5 mL of sodium ethylendiamine
be used in this procedure to 25 6 5°C and maintain this
tetraacetate solution (1 mL = 1.0 mg CaCO ), with stirring. If
temperature throughout the test.
a blue color develops, the effluent contains 0.2 meq/L or less
11.2 Fill the column approximately half full of water and
hardness and the rinse is completed. If the color is red, the end
add sufficient sample to give a bed height of 750 6 75 mm
point has not been reached. Continue the rinse until the effluent
above the top of the support. To avoid drying out of the
shows 0.2 meq/L or less hardness.
ion-exchange material, maintain a layer of liquid at least 20 to
11.9 Repeat the service run described in 11.5.
30 mm deep above the top of the bed at all times during the
procedure. 11.10 Repeat the cycle, beginning with a single backwash
11.3 Backwash with water for 10 min using a flow rate that (see 11.6), omitting the determination of bed volume. Continue
will maintain a 50 % expansion of the bed. If the supernatant with a regeneration and rinse (see 11.8), and end with a service
liquid is clear at this point, proceed to 11.4. If the liquid is run (see 11.5). Repeat the cycle until each of three successive
TABLE 1 Amount of Brine Regenerant Required for Use in Test Method A
Type of Exchange Brine Regenerant, Rate of Flow, mL Contact Time,
Regeneration Level
Material g/L brine/min/mL of exchanger min
lb/ft g/L
Synthetic organic 100 0.032 30 6.00 96.1
Greensand 50 0.027 15 1.25 20.0
Synthetic siliceous 50 0.080 20 3.00 80.1
Carbonaceous 50 0.067 15 3.15 50.5
D 1782–95 (2001)
runs agrees within 65 % of their average capacity as calcu- 16. Significance and Use
lated in accordance with Section 12.
16.1 Cation exchange materials containing sulfonic acid
groups are frequently used in the hydrogen form to exchange
12. Calculation
hydrogen ions from the resin sites for all the cations in the
12.1 Calculate the operating capacity, in milliequivalents
influent water. They are then regenerated with acid to restore
per millilitre, of the ion exchange material as
the sites to the hydrogen form for reuse. This test is designed
capacity, meq/mL 5 ~A 3 B! / S to simulate such usage.
16.2 Since each cation has a specific and different exchange
where:
equilibrium with hydrogen form exchange groups, the effi-
A = hardness of test water, meq/L,
ciency of the process will vary with the nature and concentra-
B = volume of test water used in service run, L, and
tion of the ions in the influent water. This test employs a
S = volume of sample in the bed, mL. For new materials,
mixture of the most commonly encountered ions in natural
this refers to the average volume of the material in the
waters as its standard test water is intended for comparison of
sodium form as determined in 11.4. For used materi-
theperformanceofmaterialstodeterminerelativeperformance
als, it is the average volume of the material in the
either between new materials or between new material and the
exhausted form as determined in 11.6.
same material after it has been used in the field. The test may
12.2 Calculate the operating capacity, in kilograins of cal-
also be run, if the parties concerned so agree, using the water
cium carbonate per cubic foot as follows:
to be treated. When this is done, the analysis of the influent
capacity, kilograins of CaCO /ft 5 C 3 21.8
water and the
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