1、Designation: D4607 94 (Reapproved 2011)D4607 14Standard Test Method forDetermination of Iodine Number of Activated Carbon1This standard is issued under the fixed designation D4607; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 relative activation level of unused or reactivated carbons
3、by adsorption ofiodine from aqueous solution. The amount of iodine absorbed (in milligrams) by 1 g of carbon using test conditions listed hereinis called the iodine number.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.
4、3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific hazard st
5、atements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2C819 Test Method for Specific Surface Area of Carbon or Graphite (Withdrawn 1987)3D1193 Specification for Reagent WaterD2652 Terminology Relating to Activated CarbonD2867 Test Methods for Moisture in Activated CarbonD3860 Pra
6、ctice for Determination of Adsorptive Capacity of Activated Carbon by Aqueous Phase Isotherm TechniqueE11 Specification for Woven Wire Test Sieve Cloth and Test SievesE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE287 Specification for Laboratory Glass Graduated BuretsE28
7、8 Specification for Laboratory Glass Volumetric FlasksE300 Practice for Sampling Industrial Chemicals2.2 NIST Publication:Circular 602Testing of Glass Volumetric Apparatus43. Summary of Test Method3.1 This test method is based upon a three-point adsorption isotherm (see Practices D3860).Astandard io
8、dine solution is treatedwith three different weights of activated carbon under specified conditions. The carbon treated solutions are filtered to separate thecarbon from the treated iodine solution (filtrate). Iodine remaining in the filtrate is measured by titration. The amount of iodineremoved per
9、 gram of carbon is determined for each carbon dosage and the resulting data used to plot an adsorption isotherm. Theamount of iodine adsorbed (in milligrams) per gram of carbon at a residual iodine concentration of 0.02 N is reported as the iodinenumber.3.2 Iodine concentration in the standard solut
10、ion affects the capacity of an activated carbon for iodine adsorption. Therefore,the normality of the standard iodine solution must be maintained at a constant value (0.100 6 0.001 N ) for all iodine numbermeasurements.1 This test method is under the jurisdiction of ASTM Committee D28 on Activated C
11、arbon and is the direct responsibility of Subcommittee D28.02 on Liquid PhaseEvaluation.Current edition approved March 1, 2011March 1, 2014. Published May 2011May 2014. Originally approved in 1986. Last previous edition approved in 2006 as D4607 94(2006). (Reapproved 2011). DOI: 10.1520/D4607-94R11.
12、10.1520/D4607-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historic
13、al standard is referenced on www.astm.org.4 Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indicatio
14、n of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be consid
15、ered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.3 The apparatus required consists of various laboratory glassware used to prepare solutions and contact carbon with thestandard iodine solution. Filtration a
16、nd titration equipment are also required.4. Significance and Use4.1 The iodine number is a relative indicator of porosity in an activated carbon. It does not necessarily provide a measure ofthe carbons ability to absorb other species. Iodine number may be used as an approximation of surface area for
17、 some types ofactivated carbons (see Test Method C819). However, it must be realized that any relationship between surface area and iodinenumber cannot be generalized. It varies with changes in carbon raw material, processing conditions, and pore volume distribution(see Definitions D2652).4.2 The pr
18、esence of adsorbed volatiles, sulfur; and water extractables may affect the measured iodine number of an activatedcarbon.5. ApparatusNOTE 1All volumetric measuring equipment should meet or exceed the requirements of NIST Circular 602. Volumetric glassware meeting thesespecifications is generally des
19、ignated as “Class A”. See also Specifications E287 and E288.5.1 Analytical Balance, accuracy 60.0001 g.5.2 Buret, 10-mL capacity or 5-mL precision buret.5.3 Flasks, Erlenmeyer 250-mL capacity with ground glass stoppers.5.4 Flask, Erlenmeyer wide-mouthed, 250-mL capacity.5.5 Beakers, assorted sizes.5
20、.6 Bottles, amber, for storage of iodine and thiosulfate solutions.5.7 Funnels, 100-mm top inside diameter.5.8 Filter Paper, 18.5-cm prefolded paper, Whatman No. 2V or equivalent.5.9 Pipets, volumetric type, 5.0, 10.0, 25.0, 50.0, and 100.0-mL capacity.5.10 Volumetric Flasks, 1 L.5.11 Graduated Cyli
21、nders, 100 mL and 500 mL.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specificat
22、ions are available.5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.6.2 Purity of WaterReferences to water shall be understood to mean reagent water conforming to Specific
23、ation D1193 forType II reagent water.6.3 Hydrochloric Acid, concentrated.6.4 Sodium Thiosulfate, (Na2S2O3 5H2O).6.5 Iodine, United States Pharmacopeia, resublimed crystals.6.6 Potassium Iodide.6.7 Potassium Iodate, primary standard.6.8 Starch, soluble potato or arrowroot.6.9 Sodium Carbonate.7. Haza
24、rds7.1 Several potential hazards are associated with conducting this test procedure. It is not the purpose of this standard to addressall potential health and safety hazards encountered with its use. The user is responsible for establishing appropriate health andsafety practices before use of this t
25、est procedure. Determine the applicability of federal and state regulations before attempting touse this test method.5 “Reagent Chemicals, American Chemical Society Specifications,” Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by theAmerican Chemical Socie
26、ty, see “Reagent Chemicals and Standards,” by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the “United States Pharmacopeia.”D4607 1427.2 Personnel conducting the iodine number procedure should be aware of potential safety and health hazards associated withthe chemicals used in this pro
27、cedure. The “Material Safety Data Sheet” (MSDS) for each reagent listed in Section 6 should be readand understood. Special precautions to be taken during use of each reagent are included on the “Material Safety Data Sheet”(MSDS). First aid procedures for contact with a chemical are also listed on it
28、s “MSDS.” A “Material Safety Data Sheet” for eachreagent may be obtained from the manufacturer. Other safety and health hazard information on reagents used in this procedure isavailable.6,7,87.3 Careful handling and good laboratory technique should always be used when working with chemicals. Avoid c
29、ontact withhydrochloric acid or acid vapor. Care should also be taken to prevent burns during heating of various solutions during this testprocedure.7.4 The user of this test method should comply with federal, state, and local regulations for safe disposal of all samples andreagents used.8. Preparat
30、ion of Solutions8.1 Hydrochloric Acid Solution (5 % by weight)Add 70 mL of concentrated hydrochloric acid to 550 mL of distilled waterand mix well. A graduated cylinder may be used for measurement of volume.8.2 Sodium Thiosulfate (0.100 N)Dissolve 24.820 g of sodium thiosulfate in approximately 75 6
31、 25 mL of freshly boileddistilled water. Add 0.10 6 0.01 g of sodium carbonate to minimize bacterial decomposition of the thiosulfate solution.Quantitatively transfer the mixture to a 1-L volumetric flask and dilute to the mark. Allow the solution to stand at least 4 daysbefore standardizing. The so
32、lution should be stored in an amber bottle.8.3 Standard Iodine Solution (0.100 6 0.001 N)Weigh 12.700 g of iodine and 19.100 g of potassium iodide (KI) into a beaker.Mix the dry iodine and potassium iodide. Add 2 to 5 mL of water to the beaker and stir well. Continue adding small incrementsof water
33、(approximately 5 mL each) while stirring until the total volume is 50 to 60 mL. Allow the solution to stand a minimumof 4 h to ensure that all crystals are thoroughly dissolved. Occasional stirring during this 4-h period will aid in the dissolution.Quantitatively transfer to a 1-L volumetric flask a
34、nd fill to the mark with distilled water. It is important that the standard iodinesolution has an iodide-to-iodine weight ratio of 1.5 to 1. Store the solution in an amber bottle.8.4 Potassium Iodate Solution (0.1000 N)Dry 4 or more grams of primary standard grade potassium iodate (KIO3) at 110 65C
35、for 2 h and cool to room temperature in a desiccator. Dissolve 3.5667 6 0.1 mg of the dry potassium iodate in about 100 mLof distilled water. Quantitatively transfer to a 1-L volumetric flask and fill to the mark with distilled water. Mix thoroughly andstore in a glass-stoppered bottle.8.5 Starch So
36、lutionMix 1.0 6 0.5 g of starch with 5 to 10 mL of cold water to make a paste. Add an additional 25 6 5 mLof 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. Thissolution should be made fresh daily.9. Standardization of So
37、lutions9.1 Standardization of 0.100 N Sodium Thiosulfate Pipet 25.0 mLof potassium iodate (KIO3) solution from 8.4 into a 250-mLtitration (or wide-mouthed Erlenmeyer) flask. Add 2.00 6 0.01 g of potassium iodide (KI) to the flask and shake the flask todissolve the potassium iodide crystals. Pipet 5.
38、0 mL of concentrated hydrochloric acid into the flask. Titrate the free iodine withsodium thiosulfate solution until a light yellow color is observed in the flask.Add a few drops of starch indicator (8.5) and continuethe titration dropwise until one drop produces a colorless solution. Determine sodi
39、um thiosulfate normality as follows:N15PR!/S (1)where:N 1 = sodium thiosulfate, N,P = potassium iodate, mL,R = potassium iodate, N, andS = sodium thiosulfate, mL.The titration step should be done in triplicate and the normality results averaged. Additional replications should be done if therange of
40、values exceeds 0.003 N.6 The “Chemical Safety Data Sheet” for the subject chemical is available from the Manufacturing Chemists Association, Washington, DC.7 Sax, N. I., Dangerous Properties of Industrial Materials , 4th edition, 1975, Van Nostrand Reinhold Company, New York, NY.8 NIOSH/OSHA Pocket
41、Guide to Chemical Hazards, 1978, U.S. Department of Labor, Occupational Safety and Health Administration, Washington, DC. Available fromU.S. Government Printing Office, Washington, DC.D4607 1439.2 Standardization of 0.100 6 0.001 N Iodine SolutionPipet 25.0 mL of iodine solution (8.3) into a 250-mL
42、widemouthedErlenmeyer flask. Titrate with standardized sodium thiosulfate (9.1) until the iodine solution is a light yellow color. Add a fewdrops of starch indicator and continue titration dropwise until one drop produces a colorless solution. Determine the iodine solutionnormality as follows:N25SN1
43、!/I (2)where:N 2 = iodine, N,S = sodium thiosulfate, mL,N1 = sodium thiosulfate, N, andI = iodine, mL.The titration step should be done in triplicate and the normality results averaged. Additional replications should be done if therange of values exceeds 0.003 N. The iodine solution concentration mu
44、st be 0.100 6 0.001 N. If this requirement is not met, repeat8.3 and 9.2.10. Procedure10.1 The procedure applies to either powdered or granular activated carbon. When granular carbon is to be tested, grind arepresentative sample (see Practice E300) of carbon until 60 wt % (or more will pass through
45、a 325-mesh screen) and 95 wt %or more will pass through a 100-mesh screen (U.S. sieve series, see Specification E11). Carbon received in the powdered form mayneed additional grinding to meet the particle size requirement given above.10.2 Dry the ground carbon from 10.1 in accordance with Test Method
46、 D2867. Cool the dry carbon to room temperature in adesiccator.10.3 Determination of iodine number requires an estimation of three carbon dosages. Section 11.4 describes how to estimatethe carbon dosages to be used. After estimating carbon dosages, weigh three appropriate amounts of dry carbon to th
47、e nearestmilligram. Transfer each weighed sample of carbon to a clean, dry 250-mLErlenmeyer flask equipped with a ground glass stopper.10.4 Pipet 10.0 mL of 5 wt % hydrochloric acid solution into each flask containing carbon. Stopper each flask and swirl gentlyuntil the carbon is completely wetted.
48、Loosen the stoppers to vent the flasks, place on a hot plate in a fume hood, and bring thecontents to a boil. Allow to boil gently for 30 6 2 s to remove any sulfur which may interfere with the test results. Remove theflasks from the hot plate and cool to room temperature.10.5 Pipet 100.0 mL of 0.10
49、0 N iodine solution into each flask. Standardize the iodine solution just prior to use. Stagger theaddition of iodine to the three flasks so that no delays are encountered in handling. Immediately stopper the flasks, and shake thecontents vigorously for 30 6 1 s. Quickly filter each mixture by gravity through one sheet of folded filter paper (Whatman No.2V or equivalent) into a beaker. Filtration equipment must be prepared in advance so no delay is encountered in filtering thesamples.10.6 For each filtrate, use the first 20 to 30 mL to rinse a pipet. Discard
