1、Designation: D2867 17Standard Test Methods forMoisture in Activated Carbon1This standard is issued under the fixed designation D2867; 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 parenthese
2、s indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These test methods provide two procedures for thedetermination of the
3、 moisture content of activated carbon.2Theprocedures may also be used to dry samples required for othertests. The oven drying method is used when water is the onlyvolatile material present and is in significant quantities, and theactivated carbon is not heat sensitive (some activated carbonscan igni
4、te spontaneously at temperatures as low as 150 C).The xylene extraction method is used when a carbon is knownor suspected to be heat sensitive or to contain nonwater-miscible organic compounds instead of or in addition to water.The oven drying method described in these test methods maybe used as the
5、 reference for development of instrumentaltechniques for moisture determination in activated carbon.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if
6、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.1.4 This international standard was developed in accor-dance with internationally recognize
7、d 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:3E177 Practice for Use of
8、the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Methods3.1 Oven Drying Test MethodA sample of carbon is putinto a dry, closed capsule (of known weight) and weighedaccurately. The capsul
9、e is opened and placed with the lid in apreheated oven. The sample is dried to constant weight thenremoved from the oven and with the capsule closed, cooled toambient temperature. The closed capsule is weighed againaccurately. The weight loss is expressed as a percentage of theweight of the original
10、 sample.3.2 Xylene Extraction Test MethodA known, accurateweight of carbon is put into a boiling flask.Aknown volume ofxylene is added to the flask and the flask is then connected toa water trap.Ahot plate is used to heat the xylene until boiling.The temperature is controlled to allow steady reflux.
11、 Refluxcontinues until no further water can be collected in the trap.The weight of water collected is expressed as a percentage ofthe weight of the original sample.4. Significance and Use4.1 The moisture content of activated carbon is oftenrequired to define and express its properties in relation to
12、 thenet weight of the carbon.4.2 The moisture content of activated carbon packed intypical shipping containers will usually increase during trans-portation and storage. Users of activated carbon in applicationswhere low moisture content is important should be aware ofthis effect.1These test methods
13、are under the jurisdiction of ASTM Committee D28 onActivated Carbon and are the direct responsibility of Subcommittee D28.04 on GasPhase Evaluation Tests.Current edition approved July 1, 2017. Published July 2017. Originally approvedin 1970. Last previous edition approved in 2014 as D2867 09 (2014).
14、 DOI:10.1520/D2867-17.2The moisture balance method has been used in industry when water is the onlyvolatile material present and is in significant quantities and when the activatedcarbon is not heat sensitive. A precision and bias statement for the moisture balancemethod has not been developed by AS
15、TM. Values obtained using this techniqueshould be properly correlated to one of the documented methods described in thisstandard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informati
16、on, 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization e
17、stablished in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1OVEN DRYING METHOD5. Apparatus5.1 Moisture OvenMost commercial, electrically heated,forced-circulatio
18、n drying ovens capable of temperature regu-lation between 145 and 155 C may be used.5.2 Capsules with CoversLow-form glass weighingbottles with ground-glass stoppers or seamless metal boxeswith covers may be used. They should be as shallow aspossible, consistent with convenient handling.5.3 Desiccat
19、or.6. Materials6.1 DesiccantAnhydrous calcium chloride or other suit-able desiccant.7. Procedure for Activated Carbon Passing a No. 50Sieve7.1 Dip out with a spoon or spatula from the sample bottlea 1- to 2-g representative sample. Put this into a predried taredcapsule with lid, close and weigh at o
20、nce to the nearest 0.5 mg.The depth of the carbon in the capsule must not exceed1.25 cm.7.2 Remove the cover and place the capsule and cover in apreheated forced-circulation oven (at 145 to 155 C). Close theoven and dry to constant weight (3 h normally sufficient). Openthe oven and cover the capsule
21、s quickly. Cool in a desiccator toambient temperature and weigh.8. Procedure for Activated Carbon Larger Than a No. 50Sieve8.1 Use a 5- to 10-g representative sample and weigh to thenearest 2 mg. Complete the determination as described inSection 7.9. Calculation9.1 Calculate the moisture content as
22、follows:Moisture, weight% 5 C 2 D!/C 2 B!# 3100where:B = weight of capsule with cover, g,C = weight of capsule with cover plus original sample, g,andD = weight of capsule with cover plus dried sample, g.XYLENE EXTRACTION METHOD10. Apparatus10.1 Boiling FlaskA 300-mL flat-bottom Erlenmeyerflask with
23、ground-glass joints.10.2 CondenserA 300-mm water-cooled condenser of theAllihn type with ground-glass joints.10.3 Drying Tube, containing a suitable desiccant withfiberglass filter.10.4 Water TrapA Bidwell and Sterling 10-mL or a Deanand Stark receiver with ground-glass joints. The water trapshould
24、be clean so that the shape of the meniscus at the end ofthe test is the same as at the beginning.NOTE 1The trap may be coated with a silicone resin to give a uniformmeniscus. To coat the trap, first clean it with a suitable cleaner. Rinse theclean trap with a silicone resin and after draining for a
25、few minutes, bakefor1hatapproximately 200 C.10.5 Hot PlateAn electrically heated hot plate with en-closed elements and temperature control.11. Reagent11.1 XyleneReagent-grade in accordance with the speci-fications of the Committee on Analytical Reagents of theAmerican Chemical Society.412. Hazards12
26、.1 The use of hot xylene presents a continual fire hazardand suitable fire extinguishing equipment should be available.13. Preparation of Apparatus13.1 Clean the condenser, flask, and trap and carefully dryto ensure that it is free of water. Assemble the condenser andwater trap as shown in Fig. 1.14
27、. Procedure14.1 Weigh the sample bottle. Dip out with a spoon from thesample bottle 25 to 50 g of the sample. Put this into the boilingflask and reweigh the sample bottle to the nearest 0.1 g. Add100 mL of xylene and connect the boiling flask to the watertrap. For carbons having density less than 0.
28、30 g/cm3, 200 mLof xylene should be used for a 25-g sample.14.2 Place the hot plate under the boiling flask and heat toboiling. Adjust the temperature control so as to reflux thexylene at the rate of about 1 drop/s from the tip of thecondenser. Continue to reflux until there is no further increasein
29、 the water layer in the trap over a 30-min period (from 2 to8 h may be required).15. Calculation15.1 Calculate the moisture content as follows:Moisture, weight% 5 V/C 2 E!# 3100where:V = water collected, mL,C = initial weight of sample bottle, g, andE = weight of sample bottle after removing moistur
30、e sample,g.15.2 Calculate for the correction for moisture in carbon todetermine the weight of a carbon sample on the dry basis asfollows:4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the
31、 American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D2867 172Corrected weight dry basis!5 (1)Initial weight of Carbonundried! 3 100
32、%2% moisture from 15.1!100%!16. Precision and Bias16.1 An interlaboratory test which included four laborato-ries testing in triplicate, and activated carbon samples withnominal moisture levels of 1 weight %, 5 weight %, and 12weight %, was conducted according to Practice E691. Resultsof these tests
33、yielded repeatability and reproducibility coeffi-cients at 95 % confidence levels as listed in Table 1.16.1.1 The high coefficients of variation for both testmethods when the moisture is nominally 1 weight % suggeststhat values in this range be reported as “1 weight % or less.” Ifgreater precision i
34、s needed, the amount of carbon sample canbe increased over that specified in Sections 7, 8, and 14.17. Keywords17.1 activated carbon; moistureASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of thi
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39、ndard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 1 Moisture Determination ApparatusTABLE 1 Within- and Between-Laboratory PrecisionNominal Moisture, weight % 1 5 12Oven Drying MethodRepeatability Coefficient, CV %rA19 3 6Reproducibility Coefficient, CV %RA51 13 10Xylene Extraction MethodRepeatability Coefficient, CV %rA51 5 6Reproducibility Coefficient, CV %RA54 6 6ADefined in Practice E177, Section 28.D2867 173
