1、Designation: D2867 09Standard 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 Department of Defense.1. Scope1.1 These test methods provide three procedures for thedetermination of the mo
3、isture content of activated carbon. Theprocedures may also be used to dry samples required for othertests. The oven-drying and moisture balance methods are usedwhen water is the only volatile material present and is insignificant quantities, and the activated carbon is not heat-sensitive (some activ
4、ated carbons can ignite spontaneously attemperatures as low as 150C). The xylene-extraction methodis used when a carbon is known or suspected to be heatsensitive or to contain nonwater-miscible organic compoundsinstead of or in addition to water. The oven-drying methoddescribed in these test methods
5、 may be used as the referencefor development of instrumental techniques for moisture de-termination 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 the
6、safety 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:2E177 Practice for Use of the
7、 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 capsule i
8、s 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 sa
9、mple.3.2 Xylene-Extraction Test Method A known, accurateweight of carbon is put into a boiling flask.Aknown volume ofxylene is added to the flask and the flask then connected to awater trap. A hot plate is used to heat the xylene until boiling.The temperature is controlled to allow steady reflux. Re
10、fluxcontinues 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.3.3 Moisture Balance Test MethodA sample of activatedcarbon is placed in a moisture balance and the weight measuredaccurately. The sample i
11、s dried to constant weight. The weightloss is expressed as a percentage of the weight of the originalsample.4. Significance and Use4.1 The moisture content of activated carbon is oftenrequired to define and express its properties in relation to thenet weight of the carbon.4.2 The moisture content of
12、 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.OVEN-DRYING METHOD5. Apparatus5.1 Moisture OvenMost commercial, electrically
13、 heated,forced-circulation drying ovens capable of temperature regu-lation between 145 and 155C may be used.1These test methods 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 ap
14、proved Nov. 1, 2009. Published December 2009. Originallyapproved in 1970. Last previous edition approved in 2004 as D2867 04. DOI:10.1520/D2867-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandard
15、s volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Capsules with CoversLow-form glass weighingbottles with ground-glass stoppers or seamless metal
16、 boxeswith covers may be used. They should be as shallow aspossible, consistent with convenient handling.5.3 Desiccator.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
17、 sample bottlea 1 to 2-g representative sample. Put this into a predried taredcapsule with lid, close and weigh at once to the nearest 0.5 mg.The depth of the carbon in the capsule must not exceed 1.25cm.7.2 Remove the cover and place the capsule and cover in apreheated forced circulation oven (at 1
18、45 to 155C). Close theoven and dry to constant weight (3 h normally sufficient). Openthe oven and cover the capsules quickly. Cool in a desiccator toambient temperature and weigh.8. Procedure for Activated Carbon Larger Than A No.50 Sieve8.1 Usea5to10-g representative sample and weigh to thenearest
19、2 mg. Complete the determination as described inSection 7.9. Calculation9.1 Calculate the moisture content as follows:Moisture, weight % 5 C 2 D! / C 2 B!# 3 100where:B = weight of capsule with cover, g,C = weight of capsule with cover plus original sample, g,andD = weight of capsule with cover plus
20、 dried sample, g.XYLENEEXTRACTION METHOD10. Apparatus10.1 Boiling FlaskA 300-mL flat-bottom Erlenmeyerflask with 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 withfiber-glass filter.10.4
21、Water TrapA Bidwell and Sterling 10-mL or a Deanand Stark receiver with ground-glass joints. The water trapshould 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
22、 trap, first clean it with a suitable cleaner. Rinse theclean trap with a silicone resin and after draining for a few minutes, bakefor1hatapproximately 200C.10.5 Hot PlateAn electrically heated hot plate with en-closed elements and temperature control.11. Reagent11.1 XyleneReagent grade in accordanc
23、e with the speci-fications of the Committee on Analytical Reagents of theAmerican Chemical Society.312. Hazards12.1 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 tra
24、p and carefully dryto ensure that it is free of water. Assemble the condenser andwater trap as shown in Fig. 1.14. 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
25、.1 g. Add100 mL of xylene and connect the boiling flask to the watertrap. For carbons having density less than 0.30 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
26、 the rate of about 1 drop/s from the tip of thecondenser. Continue to reflux until there is no further increasein 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!# 3 100where:
27、V = water collected, mL,C = initial weight of sample bottle, g, andE = weight of sample bottle after removing moisturesample, g.15.2 Calculate for the correction for moisture in carbon todetermine the weight of a carbon sample on the dry basis asfollows:Corrected weight dry basis!5 (1)Initial weight
28、 of Carbonundried!3100% 2 % moisture from 15.1!100%!MOISTURE BALANCE METHOD16. Apparatus16.1 Moisture balance, having a sensitivity of 0.1 mg andpreferably an indirect heating source.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestio
29、ns on the testing of reagents notlisted by the 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 092NOTE 2An indirect heatin
30、g source is preferred due to the very strongabsorption of infrared radiation by activated carbon and the resultingtemperature increase to values higher than that of the surroundingatmosphere.17. Procedure for Activated Carbon Passing a No. 50Sieve.17.1 Set up the moisture balance according to the ma
31、nufac-turers instructions. The temperature should not exceed 150C.17.2 Place a representative sample of about 1 to 2-g into themoisture balance and determine its weight to the nearest 0.1mg.17.3 Close the lid and start the machine.17.4 Once the weight loss under these drying conditions isless than 1
32、 mg over 30 s, the sample is considered dry and thepercent mass loss should be recorded to the nearest 0.1 %.18. Procedure for Activated Carbon Larger Than a No.50 Sieve18.1 Set up the moisture balance according to the manufac-turers instructions. The temperature should not exceed 150C.18.2 Place a
33、representative sample of about 5 to 10-g intothe moisture balance and determine its weight to the nearest 0.1mg.18.3 Complete the determination as described in Section 17.19. Calculation19.1 Calculate the moisture content as follows:Moisture, weight % 5 A B!/A 3 100where:A = weight of sample before
34、heating, gB = weight of sample after heating, g20. Precision and Bias20.1 An interlaboratory test which included four laborato-ries testing in triplicate, activated carbon samples with nominalmoisture levels of 1 weight %, 5 weight %, and 12 weight %,was conducted according to Practice E691. Results
35、 of thesetests yielded repeatability and reproducibility coefficients at95 % confidence levels as listed in Table 1 .20.1.1 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.” Ifgreat
36、er precision is needed, the amount of carbon sample canbe increased over that specified in Sections 7, 8, and 14.20.2 No precision and bias statement has been developed onthe moisture balance method; however, it is anticipated that itwill be developed.21. Keywords21.1 activated carbon; moistureFIG.
37、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 Coeffi
38、cient, CV %RA54 6 6ADefined in Practice E177, Section 28.D2867 093ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any s
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