1、Designation:D456719Standard Test Method forSingle-Point Determination of Specific Surface Area ofCatalysts and Catalyst Carriers Using Nitrogen Adsorptionby Continuous Flow Method1This standard is issued under the fixed designation D4567;the number immediately following the designation indicates the
2、 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 single-point determinationof t
3、he surface area of catalysts and catalyst carriers that exhibitType II or Type IV nitrogen adsorption isotherms using anitrogen-helium flowing gas mixture.This test method isapplicable for the determination of total surface areas from 0.1to 300 m2,where rapid surface area determinations are desired.
4、1.2 Because the single-point method uses an approximationof the BET equation,the multipoint BET method(Test MethodD3663)is preferred to the single-point method.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard
5、 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 consult andestablish appropriate safety,health,and environmental prac-tices and determine the applicability of regulatory limitationsprior to use.1.5 This int
6、ernational 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)Co
7、mmittee.2.Referenced Documents2.1 ASTM Standards:2D3663 Test Method for Surface Area of Catalysts andCatalyst CarriersD3766 Terminology Relating to Catalysts and CatalysisE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691
8、Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsSee Terminology D3766.3.2 Symbols:Acs=cross-sectional area of nitrogen,16.2 1020m2.CI=integrator counts.CITa=integrator counts corrected for ambient temperature.CIPa=integrator coun
9、ts corrected for ambient pressure.N=Avogadros number,6.02 1023,molecules/mole.P=partial pressure of nitrogen,torr.Pa=ambient pressure,torr.Po=saturated equilibrium vapor pressure of liquidnitrogen,torr.R=gas constant,82.1 cm3atm/K mole.Ta=ambient temperature,K.V=volume of nitrogen adsorbed at ambien
10、t temperatureand pressure,cm3.W1=tare of sample cell,g.W2=sample mass+tare of sample cell after analysis,g.Ws=mass of sample,g.4.Summary of Test Method4.1 The sample is degassed by heating in a flow of inert gasto remove adsorbed vapors from the surface.The sample isthen immersed in a liquid nitroge
11、n bath causing adsorption ofnitrogen from a flowing mixture of a fixed concentration ofnitrogen in helium.When adsorption is complete,the sample isallowed to warm to room temperature causing desorption,which results in an increase in the nitrogen concentration in theflowing mixture.The quantity of n
12、itrogen gas desorbed isdetermined by sensing the change in thermal conductivity.4.2 Calculation of the surface area is based on a modifiedform of the BET equation.1This test method is under the jurisdiction of Committee D32 on Catalysts andis the direct responsibility of Subcommittee D32.01 on Physi
13、cal-Chemical Proper-ties.Current edition approved July 1,2019.Published August 2019.Originallyapproved in 1986.Last previous edition approved in 2013 as D4567 03(2013).DOI:10.1520/D4567-19.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceas
14、tm.org.For Annual Book of ASTMStandards volume information,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 internat
15、ionally recognized principles on standardization established 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.1 5.Significance and Use5.1 This test method is useful
16、for determining the specificsurface area of catalysts and catalyst carriers for materialspecifications,manufacturing control,and research and devel-opment in the evaluation of catalysts.6.Apparatus6.1 A schematic diagram of the basic apparatus is shown inFig.1.The apparatus may be constructed of glass or metaltubing.It has the following features:6.1.1 Flow ControlA flow control system will be presentafter the gas inlet(s)to establish and control the flow of theanalysis gas at the target concentr
