ASTM_D_6647_-_18.pdf

Designation:D664718Standard Test Method forDetermination of Acid Soluble Iron via Atomic Absorption1This standard is issued under the fixed designation D6647;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 covers the determination of the acidsoluble iron content of granular and powdered activatedcarbons,using an atomic absorption spectroscopy method bydirect aspiration.Hydrochloric acid is used to extract the iron.This test method is not directly usable to determine the totaliron concentration of a sample.1.2 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For a specific hazard statement,see Section 8.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD2652 Terminology Relating to Activated CarbonE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE287 Specification for Laboratory Glass Graduated BuretsE288 Specification for Laboratory Glass Volumetric FlasksE300 Practice for Sampling Industrial ChemicalsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 NIST Publication:3Circular 602 Testing of Glass Volumetric Apparatus3.Terminology3.1 DefinitionsTerms relating to this standard are definedin Terminology D2652.3.1.1 atomic absorptionin flame atomic absorptionspectrometry,a sample is aspirated into a flame and atomized.A light beam is directed through the flame,into amonochromator,and onto a detector that measures the amountof light absorbed by the atomized element in the flame.Because each metal has its own characteristic absorptionwavelength,a source lamp of that element is used.The amountof energy at the characteristic wavelength absorbed in theflame is proportional to the concentration of the element in thesample over a limited concentration range.4.Summary of Test Method4.1 Arepresentative sample of the material to be analyzed iscollected according to Practice E300.A known weight of thesample is ground until 95%or more of the sample passes 325mesh.The ground sample is oven dried,and then mixed witha dilute hydrochloric acid.The solution is boiled for 5 min toconvert the iron into a soluble chloride,and then cooled andfiltered.The filter cake is washed with water.Then the filtrateis transferred quantitatively to a beaker.The concentration ofiron in the filtrate is measured by atomic absorption against aset of standards.The acid soluble iron concentration is thencalculated against the weight of the original sample.5.Significance and Use5.1 In certain applications,such as acid purification,acidicfood or chemical purification or decolorization,or otherapplications wherein iron may be leached out of the carbon,theuse of acid-washed carbons will reduce or eliminate colorpickup in the effluent or in the product.The acid soluble ironcontent is usually specified by the carbon supplier to preventunacceptable levels of iron leach occurring.5.2 Detection limits,sensitivity,and optimum ranges willvary with the models of atomic absorption spectrophotometers.General instrumental parameters are as follows:1This test method is under the jurisdiction of ASTM Committee D28 onActivated Carbon and is the direct responsibility of Subcommittee D28.02 on LiquidPhase Evaluation.Current edition approved May 1,2018.Published June 2018 Originally approvedin 2001.Last previous edition approved in 2011 as D6647 01(2011).DOI:10.1520/D6647-18.2For 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.3Available from National Institute of Standards and Technology(NIST),100Bureau Dr.,Stop 1070,Gaithersburg,MD 20899-1070,http:/www.nist.gov.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by t