1、Designation: D 4607 94 (Reapproved 2006)Standard Test Method forDetermination of Iodine Number of Activated Carbon1This standard is issued under the fixed designation D 4607; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the relativeactivation level of unused or reactivated carbons by ads
3、orptionof iodine from aqueous solution. The amount of iodineabsorbed (in milligrams) by1gofcarbon using test conditionslisted herein is called the iodine number.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the us
4、er of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2C 819 Test Method for Specific Surface Area of Carbon orGraph
5、iteD 1193 Specification for Reagent WaterD 2652 Terminology Relating to Activated CarbonD 2867 Test Methods for Moisture in Activated CarbonD 3860 Practice for Determination of Adsorptive Capacityof Activated Carbon by Aqueous Phase Isotherm Tech-niqueE11 Specification for Wire Cloth and Sieves for
6、TestingPurposesE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 287 Specification for Laboratory Glass Graduated BuretsE 288 Specification for Laboratory Glass Volumetric FlasksE 300 Practice for Sampling Industrial Chemicals2.2 NIST Publication:Circular 602Testing of Glas
7、s Volumetric Apparatus33. Summary of Test Method3.1 This test method is based upon a three-point adsorptionisotherm (see Practices D 3860). A standard iodine solution istreated with three different weights of activated carbon underspecified conditions. The carbon treated solutions are filtered tosep
8、arate the carbon from the treated iodine solution (filtrate).Iodine remaining in the filtrate is measured by titration. Theamount of iodine removed per gram of carbon is determinedfor each carbon dosage and the resulting data used to plot anadsorption isotherm. The amount of iodine adsorbed (inmilli
9、grams) per gram of carbon at a residual iodine concentra-tion of 0.02 N is reported as the iodine number.3.2 Iodine concentration in the standard solution affects thecapacity of an activated carbon for iodine adsorption. There-fore, the normality of the standard iodine solution must bemaintained at
10、a constant value (0.100 6 0.001 N) for all iodinenumber measurements.3.3 The apparatus required consists of various laboratoryglassware used to prepare solutions and contact carbon with thestandard iodine solution. Filtration and titration equipment arealso required.4. Significance and Use4.1 The io
11、dine number is a relative indicator of porosity inan activated carbon. It does not necessarily provide a measureof the carbons ability to absorb other species. Iodine numbermay be used as an approximation of surface area for sometypes of activated carbons (see Test Method C 819). However,it must be
12、realized that any relationship between surface areaand iodine number cannot be generalized. It varies withchanges in carbon raw material, processing conditions, andpore volume distribution (see Definitions D 2652).4.2 The presence of adsorbed volatiles, sulfur; and waterextractables may affect the m
13、easured iodine number of anactivated carbon.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 Oct. 1, 2006. Published November 2006. Originallyapproved in 198
14、6. Last previous edition approved in 1999 as D 4607 94 (1999).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
15、.3Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. ApparatusNOTE 1All volumetric measur
16、ing equipment should meet or exceedthe requirements of NIST Circular 602. Volumetric glassware meetingthese specifications is generally designated as “Class A”. See alsoSpecifications E 287 and E 288.5.1 Analytical Balance, accuracy 60.0001 g.5.2 Buret, 10-mL capacity or 5-mL precision buret.5.3 Fla
17、sks, Erlenmeyer 250-mL capacity with ground glassstoppers.5.4 Flask, Erlenmeyer wide-mouthed, 250-mL capacity.5.5 Beakers, assorted sizes.5.6 Bottles, amber, for storage of iodine and thiosulfatesolutions.5.7 Funnels, 100-mm top inside diameter.5.8 Filter Paper, 18.5-cm prefolded paper, Whatman No.2
18、V or equivalent.5.9 Pipets, volumetric type, 5.0, 10.0, 25.0, 50.0, and100.0-mL capacity.5.10 Volumetric Flasks,1L.5.11 Graduated Cylinders, 100 mL and 500 mL.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagen
19、ts shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theac
20、curacy of the determination.6.2 Purity of WaterReferences to water shall be under-stood to mean reagent water conforming to SpecificationD 1193 for Type II reagent water.6.3 Hydrochloric Acid, concentrated.6.4 Sodium Thiosulfate, (Na2S2O35H2O).6.5 Iodine, United States Pharmacopeia, resublimed crys-
21、tals.6.6 Potassium Iodide.6.7 Potassium Iodate, primary standard.6.8 Starch, soluble potato or arrowroot.6.9 Sodium Carbonate.7. Hazards7.1 Several potential hazards are associated with conductingthis test procedure. It is not the purpose of this standard toaddress all potential health and safety ha
22、zards encounteredwith its use. The user is responsible for establishing appropri-ate health and safety practices before use of this test procedure.Determine the applicability of federal and state regulationsbefore attempting to use this test method.7.2 Personnel conducting the iodine number procedur
23、eshould be aware of potential safety and health hazards associ-ated with the chemicals used in this procedure. The “MaterialSafety Data Sheet” (MSDS) for each reagent listed in Section6 should be read and understood. Special precautions to betaken during use of each reagent are included on the “Mate
24、rialSafety Data Sheet” (MSDS). First aid procedures for contactwith a chemical are also listed on its “MSDS.” A “MaterialSafety Data Sheet” for each reagent may be obtained from themanufacturer. Other safety and health hazard information onreagents used in this procedure is available.5,6 ,77.3 Caref
25、ul handling and good laboratory technique shouldalways be used when working with chemicals. Avoid contactwith hydrochloric acid or acid vapor. Care should also be takento prevent burns during heating of various solutions during thistest procedure.7.4 The user of this test method should comply with f
26、ederal,state, and local regulations for safe disposal of all samples andreagents used.8. Preparation of Solutions8.1 Hydrochloric Acid Solution (5 % by weight)Add 70mL of concentrated hydrochloric acid to 550 mL of distilledwater and mix well. A graduated cylinder may be used formeasurement of volum
27、e.8.2 Sodium Thiosulfate (0.100 N)Dissolve 24.820 g ofsodium thiosulfate in approximately 75 6 25 mL of freshlyboiled distilled water. Add 0.10 6 0.01 g of sodium carbonateto minimize bacterial decomposition of the thiosulfate solution.Quantitatively transfer the mixture to a 1-L volumetric flaskand
28、 dilute to the mark. Allow the solution to stand at least 4days before standardizing. The solution should be stored in anamber bottle.8.3 Standard Iodine Solution (0.100 6 0.001 N)Weigh12.700 g of iodine and 19.100 g of potassium iodide (KI) intoa beaker. Mix the dry iodine and potassium iodide. Add
29、 2 to 5mL of water to the beaker and stir well. Continue adding smallincrements of water (approximately 5 mL each) while stirringuntil the total volume is 50 to 60 mL. Allow the solution tostand a minimum of4htoensure that all crystals arethoroughly dissolved. Occasional stirring during this 4-h pe-
30、riod will aid in the dissolution. Quantitatively transfer to a 1-Lvolumetric flask and fill to the mark with distilled water. It isimportant that the standard iodine solution has an iodide-to-iodine weight ratio of 1.5 to 1. Store the solution in an amberbottle.8.4 Potassium Iodate Solution (0.1000
31、N)Dry 4 or moregrams of primary standard grade potassium iodate (KIO3)at110 6 5C for 2 h and cool to room temperature in a desiccator.Dissolve 3.5667 6 0.1 mg of the dry potassium iodate in about100 mL of distilled water. Quantitatively transfer to a 1-Lvolumetric flask and fill to the mark with dis
32、tilled water. Mixthoroughly and store in a glass-stoppered bottle.4“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-cal Soc., Washington, DC. For suggestions on the testing of reagents not listed bytheAmerican Chemical Society, see “Reagent Chemicals and Standards,” by Joseph
33、Rosin, D. Van Nostrand Co., Inc., New York, NY, and the “United StatesPharmacopeia.”5The “Chemical Safety Data Sheet” for the subject chemical is available fromthe Manufacturing Chemists Association, Washington, DC.6Sax, N. I., Dangerous Properties of Industrial Materials , 4th edition, 1975,Van Nos
34、trand Reinhold Company, New York, NY.7NIOSH/OSHA Pocket Guide to Chemical Hazards, 1978, U.S. Department ofLabor, Occupational Safety and Health Administration, Washington, DC. Availablefrom U.S. Government Printing Office, Washington, DC.D 4607 94 (2006)28.5 Starch SolutionMix 1.0 6 0.5 g of starch
35、 with 5 to 10mL of cold water to make a paste. Add an additional 25 6 5mL of water while stirring to the starch paste. Pour the mixture,while stirring, into 1 L of boiling water and boil for 4 to 5 min.This solution should be made fresh daily.9. Standardization of Solutions9.1 Standardization of 0.1
36、00 N Sodium ThiosulfatePipet25.0 mL of potassium iodate (KIO3) solution from 8.4 into a250-mL titration (or wide-mouthed Erlenmeyer) flask. Add2.00 6 0.01 g of potassium iodide (KI) to the flask and shakethe flask to dissolve the potassium iodide crystals. Pipet 5.0 mLof concentrated hydrochloric ac
37、id into the flask. Titrate the freeiodine with sodium thiosulfate solution until a light yellowcolor is observed in the flask. Add a few drops of starchindicator (8.5) and continue the titration dropwise until onedrop produces a colorless solution. Determine sodium thiosul-fate normality as follows:
38、N15 PR!/S (1)where:N1= sodium thiosulfate, N,P = potassium iodate, mL,R = potassium iodate, N, andS = sodium thiosulfate, mL.The titration step should be done in triplicate and thenormality results averaged. Additional replications should bedone if the range of values exceeds 0.003 N.9.2 Standardiza
39、tion of 0.100 6 0.001 N Iodine SolutionPipet 25.0 mL of iodine solution (8.3) into a 250-mL widemo-uthed Erlenmeyer flask. Titrate with standardized sodiumthiosulfate (9.1) until the iodine solution is a light yellow color.Add a few drops of starch indicator and continue titrationdropwise until one
40、drop produces a colorless solution. Deter-mine the iodine solution normality as follows:N25 S N1!/I (2)where:N2= iodine, N,S = sodium thiosulfate, mL,N1= sodium thiosulfate, N, andI = iodine, mL.The titration step should be done in triplicate and thenormality results averaged. Additional replication
41、s should bedone if the range of values exceeds 0.003 N. The iodinesolution concentration must be 0.100 6 0.001 N. If thisrequirement is not met, repeat 8.3 and 9.2.10. Procedure10.1 The procedure applies to either powdered or granularactivated carbon. When granular carbon is to be tested, grind arep
42、resentative sample (see Practice E 300) of carbon until 60wt % (or more will pass through a 325-mesh screen) and 95wt % or more will pass through a 100-mesh screen (U.S. sieveseries, see Specification E11). Carbon received in the pow-dered form may need additional grinding to meet the particlesize r
43、equirement given above.10.2 Dry the ground carbon from 10.1 in accordance withTest Method D 2867. Cool the dry carbon to room temperaturein a desiccator.10.3 Determination of iodine number requires an estimationof three carbon dosages. Section 11.4 describes how toestimate the carbon dosages to be u
44、sed.After estimating carbondosages, weigh three appropriate amounts of dry carbon to thenearest milligram. Transfer each weighed sample of carbon toa clean, dry 250-mL Erlenmeyer flask equipped with a groundglass stopper.10.4 Pipet 10.0 mL of 5 wt % hydrochloric acid solutioninto each flask containi
45、ng carbon. Stopper each flask and swirlgently until the carbon is completely wetted. Loosen thestoppers to vent the flasks, place on a hot plate in a fume hood,and bring the contents to a boil. Allow to boil gently for 30 62 s to remove any sulfur which may interfere with the testresults. Remove the
46、 flasks from the hot plate and cool to roomtemperature.10.5 Pipet 100.0 mL of 0.100 N iodine solution into eachflask. Standardize the iodine solution just prior to use. Staggerthe addition of iodine to the three flasks so that no delays areencountered in handling. Immediately stopper the flasks, and
47、shake the contents vigorously for 30 6 1 s. Quickly filter eachmixture by gravity through one sheet of folded filter paper(Whatman No. 2V or equivalent) into a beaker. Filtrationequipment must be prepared in advance so no delay isencountered in filtering the samples.10.6 For each filtrate, use the f
48、irst 20 to 30 mL to rinse apipet. Discard the rinse portions. Use clean beakers to collectthe remaining filtrates. Mix each filtrate by swirling the beakerand pipet 50.0 mL of each filtrate into a clean 250-mLErlenmeyer flask. Titrate each filtrate with standardized 0.100N sodium thiosulfate solutio
49、n until the solution is a paleyellow. Add 2 mL of the starch indicator solution and continuethe titration with sodium thiosulfate until one drop produces acolorless solution. Record the volume of sodium thiosulfateused.11. Calculation11.1 The capacity of a carbon for any adsorbate is depen-dent upon the concentration of the adsorbate in solution. Theconcentrations of the standard iodine solution and filtrates mustbe specified or known. This is necessary to determine anappropriate carbon weight to produce final concentrationsagreeing with the definition of iodine nu
