1、Designation: D4548 11Standard Test Method forAnion-Cation Balance of Mixed Bed Ion-Exchange Resins1This standard is issued under the fixed designation D4548; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method determines the ratio between theequivalents of anion-exchange capacity and the equivalents ofcation-exchange capac
3、ity present in a physical mixture ofsalt-splitting anion-exchange material and salt-splitting cation-exchange material.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is t
4、heresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1129 Terminology Relating to Water2D 1193 Specification for Reagent Water2D 2187 Tes
5、t Methods for Physical and Chemical Propertiesof Particulate Ion-Exchange Resins33. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D 1129D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 anion-exchange material, nan ion-exchange mate-ri
6、al capable of the reversible exchange of negatively chargedions.3.2.2 cation-exchange material, nan ion-exchange mate-rial capable of the reversible exchange of positively chargedions.3.2.3 ion-exchange material, nan insoluble material thathas the ability to exchange reversibly certain ions in itsst
7、ructure or attached to its surface as functional groups withions in a surrounding medium.3.2.4 ion-exchange resin, na synthetic organic ion-exchange material.3.2.5 mixed bed, na physical mixture of anion-exchangematerial and cation-exchange material.3.2.6 salt-splitting, adjthe ability of anion-exch
8、ange orcation-exchange materials to exchange hydroxide or hydrogenions respectively for the ions in neutral salts.4. Summary of Test Method4.1 This test method consists of simultaneous conversion ofthe cation-exchange component to the hydrogen form and theanion-exchange component to the chloride for
9、m with hydro-chloric acid. After rinsing to remove the excess acid, thehydrogen ion from the cation resin and the chloride ion fromthe anion resin are simultaneously eluted with neutral sodiumnitrate, and the amount eluted is determined by titration of theeffluent for both ions.5. Significance and U
10、se5.1 This test method is applicable to the analysis of newmaterials that are sold as mixtures and to samples taken fromregenerable units containing mixtures of anion-exchanging andcation-exchanging materials. It is used to determine the ratio ofthe components without separating them from each other
11、.5.2 This test method is intended for mixtures of ion-exchange materials that have salt-splitting capacity as mea-sured by Test Method E of Test Methods D 2187D 2187 forcation-exchange resins, and Test Method H for anion-exchangeresins. In the case of cation-exchange resins, these are styrene-based
12、polymers with sulfonic acid functional groups. Theanion-exchanging materials in this class are styrene-basedmaterials with quaternary ammonium functional groups. Thetest method will determine the amount of anion-exchangematerial of any functionality present in the mixture. However,when anionic group
13、s that are not salt-splitting are present, thevalues for cationic groups will be high due to the acidic1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.08 on Membranes and IonExchange Materials.Current edition approved May
14、 1, 2011. Published July 2011. Originally pub-lished 1986. Last previous edition D 4548 86. which was withdrawn 2007 andreinstated in May 2011. DOI: 10.1520/D4548112Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 11.02.1Copyright ASTM International, 100 Barr Harbor Drive
15、, PO Box C700, West Conshohocken, PA 19428-2959, United States.character of the anion effluent. Cationic groups that do not splitsalts are not measured.5.3 Samples are analyzed in this test method as received. Itis not necessary that the cation-exchanging resin be in thehydrogen form and the anion-e
16、xchanging resin be in thehydroxide form for this test method.5.4 This test method may be used to determine if newmaterials are balanced to meet their specification values. Inoperating regenerable units, it may be used to determine if thecomponents are separating properly or remixing properly. Itmay
17、also be used to check for improper balance in bedding orfor loss of a component during operation.5.5 This test method begins with the conversion to thehydrogen and chloride forms. However, it may be combinedwith the determination of the residual chloride and sulfate sitesby elution with sodium nitra
18、te as described in Test Methods Jand L in Test Methods D 2187D 2187. In such cases thehydrogen ion as well as the chloride ion is determined in thesecond sodium nitrate elution described in Test Method I ofTest Methods D 2187D 2187, and the calculations given hereinare made using the titration value
19、s so determined.6. Apparatus6.1 Test Apparatus, as shown in Fig. 1, shall consist of afilter tube of at least 30 mL in capacity having a diameter of atleast 20 mm, containing a sintered glass plate of coarse (A)porosity, a 1-L separatory funnel, and a 1-L volumetric flask.7. Reagents and Materials7.
20、1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee onAnalytical Reagents of theAmerican Chemical Society.4Other grades may be used, provided it is first ascertained t
21、hatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water, conform-ing to Specification D 1193D 1193, Type IV.7.3 Ammonium Hydroxide (1
22、+ 9)Pour 1 vol of ammo-nium hydroxide (sp gr 0.90) into 9 vol of water and mix well.7.4 Hydrochloric Acid (1 + 9)Carefully pour 100 mL ofhydrochloric acid (sp gr 1.19) into 500 mL of water, stirringconstantly. Cool to 25 6 5C and dilute to 1 L.7.5 Isopropyl Alcohol, neutral.7.6 Methyl Orange Indicat
23、or Solution (0.5 g/L)Dissolve0.05 g of methyl orange in water and dilute to 100 mL withwater.7.7 Nitric Acid (1 + 9)Pour 1 vol of nitric acid (sp gr1.42) into 9 vol of water and mix thoroughly.7.8 Phenolphthalein Indicator Solution (5.0 g/L)Dissolve0.5 g of phenolphthalein in 50 mL of 95 % ethanol (
24、see Note1). Transfer to a volumetric flask and dilute to 100 mL withwater.NOTE 1Isopropyl alcohol or specially denatured ethyl alcohol con-forming to Formula 3A or 30 of the US Bureau of Internal Revenue maybe substituted for 95 % alcohol.7.9 Potassium Chromate Solution (50 g/L)Dissolve 5.0 gof pota
25、ssium chromate in 50 mL of water. Dilute to 100 mLwith water.7.10 Silver Nitrate Solution, Standard (0.10 N)Dry crys-talline silver nitrate at 105C for 1 h and cool in a desiccator.Weigh out 176 0.05 g of AgNO3. Transfer to a 1-L volumetricflask with water. Dissolve in 500 mL of water. Dilute to 1-L
26、with water at 25 6 5C and mix well. Store the solution in atightly stoppered amber glass bottle.7.10.1 To standardize, dry approximately5gofsodiumchloride in a glass container at 105C for 2 h. Cool in adesiccator. Weigh accurately three 0.25 6 0.01 g portions ofthe dried NaCl and transfer to separat
27、e 250 mL conical flasks.Add 100 mL of water and dissolve the NaCl. Add 1 mL ofK2CrO4solution (50 g/L) and titrate with the 0.1 N AgNO3standard solution with vigorous swirling until the color changeof the solution from yellow to red-orange persists for 30 s.7.10.2 Calculate the normality of the AgNO3
28、standardsolution as follows:Ns5 A/0.05845 3 B!where:Ns= normality of the AgNO3standard solution,A = actual grams of NaCl used, andB = AgNO3standard solution required for the titration,mL.7.11 Sodium Hydroxide Solution, 50 %Prepare a 50 %solution by dissolving 162 g of sodium hydroxide pellets in150
29、mL of freshly boiled and cooled water. Cool to 25 6 5Cand decant the clear liquid. Store in a plastic bottle.7.12 Sodium Hydroxide Solution, Standard (0.10 N)Measure 5.45 mL or 8.0 g 50 % sodium hydroxide solution ina 10 mL graduated cylinder, calibrated to contain. Rinse the4Reagent Chemicals, Amer
30、ican Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary
31、, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Typical Arrangement of Apparatus for Salt-SplittingCapacityD4548 112solution into a 1-L volumetric flask with freshly boiled water at25 6 5C, dilute to 1 L, and mix well. Standardize monthly.7.12.1 To standardize, dry approximately 10
32、 g of primarystandard grade potassium hydrogen phthalate in a glass con-tainer at 120C for 2 h. Cool in a desiccator. Weigh accuratelythree 1.00 g samples of the dried potassium hydrogen phthalateand transfer to separate 250 mL conical flasks. Add 100 mL offreshly boiled and cooled water and dissolv
33、e the sample.Titrate with the 0.1 N NaOH solution electrometrically to a pHof 8.6 or add two drops of phenolphthalein indicator solutionand titrate to the first pink that persists for 15 s with swirling.7.12.2 Calculate the normality of the NaOH solution asfollows:NB5 C /0.20423 3 D!where:NB= normal
34、ity of the NaOH solution,C = actual grams of KHC8H4O4used, andD = NaOH used in the titration, mL.7.13 Sodium Nitrate Solution (20 g/L)Dissolve 20 g ofsodium nitrate in 500 mL of water. Dilute to 1 L and mix well.8. Procedure8.1 Weigh accurately into separate 100 mL beakers three20.0 g representative
35、 portions of the material.8.2 Quantitatively rinse the weighed samples into the filtertubes with water. Fill three separatory funnels with 1 L each ofHCl (1 + 9). Fill the filter tubes with acid and tap to remove airbubbles. Attach the stems of the funnels to the filter tubes withrubber stoppers of
36、suitable size. Pass the acid through thesamples at a rate of 20 to 25 mL/min, keeping the samplescovered with acid at all times. Drain the liquid to the samplelevel. Discard the effluent.8.3 Rinse the separatory funnels thoroughly with water andthen with three 10 mL portions of isopropyl alcohol. Ru
37、nisopropyl alcohol through the acid-treated samples at the rateof 20 to 25 mL/min until a 10 mL portion of the effluent, mixedwith 10 mL of water, is yellow to methyl orange or has a pHabove 3.9. Drain to the sample level and discard the effluent.8.4 Rinse the volumetric flasks thoroughly with water
38、 andreposition them under the tip of the filter tubes. Fill theseparatory funnels with 1 L each of NaNO3(20 g/L). Pass theNaNO3solution through the sample at a rate of 20 to 25mL/min, keeping the sample covered at all times, until 1 L ofeffluent is collected.8.5 Mix the effluent thoroughly. Pipet th
39、ree 100 mL portionsof each into separate 250 mL conical flasks. Add two drops ofphenolphthalein indicator solution to each and titrate with 0.1N NaOH solution to the first pink that will persist for 15 s withswirling or titrate electrometrically to a pH of 8.6. Record thevolume of NaOH solution used
40、 in each titrating to the nearest0.01 mL. Use the average of the three titrations for each sampleas E (see Section 9).8.6 To the neutralized solutions obtained in 8.5, add fourdrops of methyl orange indicator solution and HNO3(1+9)dropwise until the solution is red. Add NH4OH (1 + 9) drop-wise until
41、 the solution is again just yellow. Add 1 mL ofK2CrO4solution (50 g/L) and titrate with the 0.1 N AgNO3standard solution with vigorous swirling until the color changeof the solution from yellow to red-orange persists for 30 s.Record the volume of AgNO3solution used in each titration tothe nearest 0.
42、01 mL. Use the average of the three titrations foreach sample as F (see Section 9).NOTE 2Alternatively, pipet three 100 mL portions of the effluent intoseparate 250 mL conical flasks.Add four drops of methyl orange indicatorsolution and add NH4OH (1 + 9) dropwise until the solution is just yellow.Th
43、en continue as described in 8.6.9. Calculation9.1 Calculate the anion-cation balance as follows:R 5F 3 NsE 3 NBwhere:R = ratio between the anion capacity and the salt-splittingcation capacity,F = AgNO3used in 8.6, mL,Ns= normality of the AgNO3from 7.10.2,E = NaOH used in 8.5, mL, andNB= normality of
44、 the NaOH from 7.12.2.10. Report10.1 Report the anion-cation balance in the mixed bed as theaverage of the results of the three samples.11. Precision and Bias11.1 PrecisionPrecision was determined from the resultsof the analyses of eight operators, each analyzing threedifferent samples on each of th
45、ree different days. The overallprecision is expressed as follows:St5 0.03 x 1 0.005where:St= overall precision andx = value measured as anion-cation balance.The single operator precision is as follows:So5 0.02 x 2 0.01where:So= single operator precision andx = value measured as anion-cation balance.
46、11.2 BiasIon-exchange resins are the product of a com-plex multiple step synthesis involving a polymerization reac-tion followed by one or more additional reactions to putfunctional groups on the polymeric structure. Consequently,the true value of any property of the finished product isunknown, and
47、a bias statement cannot be given.12. Keywords12.1 anion-cation balance; ion exchange; mixed bedD4548 113ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that
48、determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapprove
49、d or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohoc
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