ASTM D1782-95(2007)
(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:
Sections Test Method A—Sodium Cycle 8 to 14 Test 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 2007)
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 Definitions of Terms Specific to This Standard: Certain
terms in these test methods that relate specifically to ion
1.1 These test methods cover the determination of the
exchange are defined as follows:
operating capacity of particulate cation-exchange materials
3.2.1 free mineral acidity—the quantitative capacity of
whenusedfortheremovalofcalcium,magnesium,andsodium
aqueous media to react with hydroxyl ions to pH 4.3.
ions from water. It is intended for use in testing both new and
3.2.2 hydrogen cycle—the operation of a cation-exchange
used materials. The following two test methods are included:
cycle wherein the removal of specified cations from influent
Sections
water is accomplished by exchange with an equivalent amount
Test Method A—Sodium Cycle 8 to 14
Test Method B—Hydrogen Cycle 15 to 21
of hydrogen ion from the exchange material.
3.2.3 theoretical free mineral acidity—the free mineral
1.2 The values given in SI units are to be regarded as the
acidity that would result from the conversion of the anions of
standard. The inch-pound units given in parentheses are for
strong acids in solution to their respective free acids.
information only.
1.3 This standard does not purport to address all of the
4. Summary of Test Methods
safety concerns, if any, associated with its use. It is the
4.1 Test MethodAconsists of repeated cycles of backwash,
responsibility of the user of this standard to establish appro-
brine regeneration, rinse, and exhaustion of the sample in the
priate safety and health practices and determine the applica-
form of a bed in a transparent column.The exhausting medium
bility of regulatory limitations prior to use.
used is an ion-exchange test water.
2. Referenced Documents
4.2 Test Method B consists of repeated cycles of backwash,
acid regeneration, rinse, and exhaustion of the sample in the
2.1 ASTM Standards:
form of a bed in a transparent column.The exhausting medium
D 1067 Test Methods for Acidity or Alkalinity of Water
used is an ion-exchange test water.
D 1126 Test Method for Hardness in Water
D 1129 Terminology Relating to Water
5. Apparatus
D 1193 Specification for Reagent Water
5.1 Test Assemble (see Fig. 1), consisting of the following:
D 2687 Practices for Sampling Particulate Ion-Exchange
5.1.1 Column, transparent, vertically supported, 25.4 6 2.5
Materials
mm (1.0 6 0.1 in.) in inside diameter and approximately 1500
3. Terminology
mm(60in.)long.Thebottomofthecolumnshallbeclosedand
provided with an outlet of approximately 6-mm inside diam-
3.1 Definitions:
eter. Connections shall be provided at top and bottom for
3.1.1 For definitions of terms used in these test methods,
admission and removal of solutions as described in Section 10.
refer to Terminology D 1129.
Adequate means for measuring and regulating flow shall be
provided. Calibrate the column in such a manner that the
These test methods are under the jurisdiction of ASTM Committee D19 on
volume readings required by the test method can be made.
Water and are the direct responsibility of Subcommittee D19.08 on Membranes and
Make all measurements at 25 6 5°C.
Ion Exchange Materials.
5.1.2 Support, for the sample, so designed that the distance
Current edition approved Dec. 1, 2007. Published December 2007. Originally
approved in 1960. Last previous edition approved in 2001 as D 1782 – 95 (2001).
from the sample to the column outlet is at least 50 mm. A
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
suggested supporting bed utilizes quartz, glass beads, or other
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
material 1.5 to 3.5 mm in diameter, insoluble in the reagents
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. used, and retained on a corrosion-resistant screen. However,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 1782–95 (2007)
FIG. 1 Typical Arrangement of Apparatus for Performance Testing of Ion-Exchange Materials
other supports such as fritted glass or polyester screens may be the manufacturer’s original packages or from a bed of used
used at the discretion of the interested parties. material, refer to Practices D 2687.
7.2 Transfer the laboratory sample to a 2-L beaker and add
6. Reagents
enough water to bring the water level up to that of the
6.1 Purity of Reagents—Reagent grade chemicals shall be
ion-exchange material and soak for 1 h (see Note 1). Mix the
used in all tests. Unless otherwise indicated, it is intended that
sample thoroughly and transfer a sufficient representative
all reagents shall conform to the specifications of the Commit-
portion to fill a 400-mL beaker. Use this portion of sample in
tee onAnalytical Reagents of theAmerican Chemical Society,
the procedure.
where such specifications are available. Other grades may be
NOTE 1—Where new materials are shipped dry, follow the manufac-
used, provided it is first ascertained that the reagent is of
turer’s instructions for preconditioning.
sufficiently high purity to permit its use without lessening the
accuracy of the determination. TEST METHOD A—SODIUM CYCLE
6.2 Purity of Water—Unless otherwise indicated, references
8. Scope
to water shall be understood to mean reagent water, Type IV,
conforming to Specification D 1193.
8.1 This test method is designed to simulate operating
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
9.1 Cation exchange materials are frequently used in the
sodium form to exchange divalent and trivalent ions in the
Reagent Chemicals, American Chemical Society Specifications , American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
influent water for sodium ions on the resin sites. This process
listed by the American Chemical Society, see Analar Standards for Laboratory
is commonly referred to as softening water since it removes
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
those ions that form a “hard” curd of insoluble salts with the
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
MD. fatty acids used in some soaps and that also precipitate when
D 1782–95 (2007)
water is boiled. In such a process, sodium chloride is used as 11.2 Fill the column approximately half full of water and
the regenerant to return the cation-exchanging groups to the add sufficient sample to give a bed height of 750 6 75 mm
sodium form. above the top of the support. To avoid drying out of the
9.2 Thistestmethodisintendedtosimulatetheperformance ion-exchange material, maintain a layer of liquid at least 20 to
of such materials in actual usage. It may be used either to 30 mm deep above the top of the bed at all times during the
compare the performance of new materials or to compare the procedure.
performance of a material that has been used with its original
11.3 Backwash with water for 10 min using a flow rate that
performance. will maintain a 50 % expansion of the bed. If the supernatant
9.3 Regenerant concentrations and dosages used herein are
liquid is clear at this point, proceed to 11.4. If the liquid is
typical for the types of materials used in this application. If cloudy (indicating the presence of light, insoluble, extraneous
different concentrations or amounts of regenerant are agreed
material), adjust the backwash outlet tube to a height above the
upon by parties using this test method, this fact should be bed equal to 75 % of the bed height. Continue backwashing at
stated when the results are reported. Similarly, the test water
the same rate until the effluent is clear.
specified is the agreed upon standard. Where other test waters
11.4 Allow the bed to settle and then drain at a rate of
orthewatertobetreatedareusedinthetest,theanalysisofthe
approximately100mL/minuntilthewaterlevelis20to30mm
water in terms of total solids, sodium, calcium, magnesium,
above the top of the bed. Do not jar. Record the volume, in
other di- or trivalent metals as well as the major anions present
millilitres, of ion-exchange material. Repeat the 10-min back-
should be reported with the test results.
wash until two successive readings of volume agree within 5
mL. The average of these two readings shall be the sample
10. Reagents and Materials
volume for new materials shipped in the sodium form.
10.1 Brine Regenerants: 11.5 Exhaust the ion exchanger with cation-exchange test
10.1.1 For synthetic organic ion-exchange materials: water A at a flow rate of 0.33 mL/min/mL of exchanger, as
10.1.1.1 Sodium Chloride (100 g/L)—Dissolve enough so- measured in 11.4. Maintain a head of liquid not less than 50
dium chloride (NaCl) in water to make a solution containing in mmabovethetopofthebed.Continuetherununtiltheeffluent
each litre 100.0 g of NaCl. shows 0.2 meq/L (or other agreed-upon hardness level) when
10.1.2 For all other ion-exchange materials: tested in accordance with Test Method D 1126. Record the
10.1.2.1 Sodium Chloride (50 g/L)—Dissolve enough NaCl volume of test water used.
in water to make a solution containing in each litre 50.0 g of
11.6 Repeat the 10-min backwash and drain as described in
NaCl. 11.3 and 11.4. When testing new material shipped in the
10.2 Cation-Exchange Test Water A (10 meq/L)—Dissolve
sodium form, only one backwash is necessary at this point
enough calcium chloride (CaCl ·2H O) and magnesium sulfate because a determination of volume has already been made.
2 2
(MgSO ·7H O) in water to make a solution containing, in each
However, used material other than in the sodium form must
4 2
litre, 0.49 g of CaCl ·2H O and 0.415 g of MgSO ·7H O. have a volume determination made here as described in 11.4.
2 2 4 2
Adjust the pH to 7.5 by the addition of Na CO (30 g/L) and
Use this sample volume determined on the exhausted material
2 3
determine the hardness of the solution in accordance with Test in calculating the capacity of used ion-exchange materials.
Method D 1126. The hardness of the test water will be 10.0 6
11.7 Determine the amount of brine regenerant and rate
0.5 meq/L. Use the determined hardness in calculating operat-
required, from Table 1. For use with Table 1, the volume
ing capacity as indicated in 12.1. This test water shall be used
sample for new material shall be that determined in accordance
for all tests.
with 11.4 and for used material shall be that determined in
10.3 Hardness Test Reagents—For reagents used in deter-
accordance with 11.6.
mining hardness, refer to Test Method D 1126. This reagent is
11.8 Pass the specified volume of brine regenerant through
used only in preparation of test water (see 10.2).
the bed at the specified rate until only a 20 to 30-mm layer of
10.4 Sodium Carbonate Solution (30 g/L)—Dissolve30gof
liquid remains above the bed. Rinse the bed with water, using
sodium carbonate (Na CO ) in water and dilute to 1 L.
2 3 the same rate, until one bed-volume of liquid has been
displaced. Increase the rinse rate to approximately 100 mL/
11. Procedure
min. Test for hardness at 3-min intervals by adding 0.5 mL of
11.1 Adjust the temperature of the water and all solutions to buffer solution to 50 mLof the effluent followed by three drops
be used in this procedure to 25 6 5°C and maintain this of hardness indicator and 0.5 mL of sodium ethylendiamine
temperature throughout the test. tetraacetate solution (1 mL = 1.0 mg CaCO ), with stirring. If
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 (2007)
a blue color develops, the effluent contains 0.2 meq/L or less
C = operating capacity, meq/mL.
hardness and the rinse is completed. If the color is red, the end
14.3 Bias—Because materials with known operating capac-
point has not been reached. Continue the rinse until the effluent
ity cannot be prepared, bias cannot be determined.
shows 0.2 meq/L or less hardness.
11.9 Repeat the service run described in 11.5.
TEST METHOD B—HYDROGEN CYCLE
11.10 Repeat the cycle, beginning with a single backwash
(see 11.6), omitting the determination of bed volume. Continue
15. Scope
with a regeneration and rinse (see 11.8), and end with a service
15.1 This test method is designed to simulate operating
run (see 11.5). Repeat the cycle until each of three successive
conditions on a hydrogen cycle used for the removal of all
runs agrees within 65 % of their average capacity as calcu-
other cations from water.
lated in accordance with Section 12.
16. Significance and Use
12. Calculation
16.1 Cation exchange materials containing sulfonic acid
12.1 Calculate the operating capacity, in milliequivalents
groups are frequently used in the hydrogen form to exchange
per millilitre, of the ion exchange material as
hydrogen ions from the resin sites for all the cations in the
capacity, meq/mL 5 ~A 3 B!/ S
influent water. They are then regenerated with acid to restore
the sites to the hydrogen form for reuse. This test is designed
where:
to simulate such usage.
A = hardness of test water, meq/L,
16.2 Since each cation has a specific and different exchange
B = volume of test water used in service run, L, and
equilibrium with hydrogen form exchange groups, the effi-
S = volume of sample in the bed, mL. For new materials,
ciency of the process will vary with the nature and concentra-
this refers to the average volume of the material in the
tion of the ions in the influent water. This test employs a
sodium form as determined in 11.4. For used materi-
mixture of the most commonly encountered ions in natural
als, it is the average volume of the material in the
waters as its standard test water is intended for comparison of
exhausted form as determined in 1
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