ASTM_D_4548_-_11.pdf

Designation:D454811Standard 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.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 capacity 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 theresponsibility 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:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2187 Test Methods for Physical and Chemical Propertiesof Particulate Ion-Exchange Resins3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 anion-exchange material,nan ion-exchange mate-rial 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 itsstructure 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-exchange 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 form 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 Use5.1 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.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 D2187 for cation-exchange resins,and Test Method H for anion-exchange resins.In the case of cation-exchange resins,these are styrene-basedpolymers with sulfonic acid functional groups.The anion-exchanging materials in this class are styrene-based materialswith quaternary ammonium functional groups.The test methodwill determine the amount of anion-exchange material of anyfunctionality present in the mixture.However,when anionicgroups that are not salt-splitting are present,the values forcationic groups will be high due to the acidic character of theanion effluent.Cationic groups that do not split salts are notmeasured.5.3 Samples are analyzed in this test method as received.Itis not necessary that the cation-exchanging resin be in the1This 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 1,2011.Published July 2011.Originally pub-lished 1986.Last previous edition D4548 86.which was withdrawn 2007 andreinstated in May 2011.DOI:10.1520/D454811.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 hydrogen form and the anion-exchanging 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 also be used to check for improper balance in bedding orfor loss of a component during operation.5.5 This test method be