1、Designation: D6761 07 (Reapproved 2012)Standard Test Method forDetermination of the Total Pore Volume of Catalysts andCatalyst Carriers1This standard is issued under the fixed designation D6761; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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 determination of the totalpore volume of catalysts and catalyst ca
3、rriers, that is, thevolume of pores having pore diameter between approximately14 m and 0.4 nm (4 ).1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 WARNINGMercury has been designated by manyregulatory agencies as a hazard
4、ous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for deta
5、ils and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional information. Users should be aware that selling mercuryand/or mercury containing products into your state or countrymay be prohibited by law.1.4 This standard does not purport to address all of thesafety concerns, if any, associated
6、 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. Specific hazardstatements are given in Section 8. Warning statements aregiven in 9.1.4, 9.1.7, and 9.1.11
7、.2. Referenced Documents2.1 ASTM Standards:2D3766 Terminology Relating to Catalysts and CatalysisE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision
8、 of a Test Method3. Terminology3.1 Definitions:3.1.1 particle volumethe volume of a particle includingpores into which mercury cannot penetrate at ambient pressure(smaller than approximately 14 m diameter pore mouth).3.1.2 true volumethe volume of a particle, includingpores, into which helium cannot
9、 penetrate (smaller than aboutapproximately 0.4 nm (4 ) diameter pore mouth).3.1.3 Other definitions and terms used in this test methodare defined in Terminology D3766.3.2 Symbols for Mercury Intrusion:W = mass of sampleWc= mass of sealed empty sample cellW8C= mass of sealed sample cell filled with
10、mercuryWs= mass of sealed sample cell with sampleW8S= mass of sealed sample cell with sample filledwith mercuryVHgC= volume of mercury in empty sample cell (volumeof sample cell)VHgS= volume of mercury in cell with sampleVSHg= sample volume, cm3VHg= specific sample volumeVP= particle volumeWb= weigh
11、t mercury reservoir after filling burette withsampleWb8= mass of mercury reservoir after filling burettewithout sample3.3 Symbols for Helium Pycnometry:VC= volume of sample cell and associated tubing, cm3VR= reference volume, cm3VSHe= sample volume, cm3VCyl= volume of calibration cylinder, cm3VSTD=
12、volume of calibration standard, cm31This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.02 on Physical-Mechanical Properties.Current edition approved May 1, 2012. Published July 2012. Originally approvedin 2002. Last previ
13、ous edition approved in 2007 as D676107. DOI: 10.1520/D6761-07R12.2For 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 web
14、site.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.VHe= specific sample volumeP81= pressure in empty sample cell, psig or pascalsP82= pressure in empty sample cell, after the referencevolume has been included in the system, psig or
15、pascalsP1= pressure in sample cell with sample or calibrationstandard before the reference volume has beenincluded in the system, psig or pascalsP2= pressure with sample or calibration standard inthe sample cell, after the reference volume hasbeen included in the system, psig or pascalsW1= tare weig
16、ht of sample cup, gW2= mass of sample + tare weight of sample cup, gW3= mass of sample, gP.V. = pore volume4. Summary of Test Method4.1 The total pore volume of a catalyst or catalyst carrier isdetermined as the difference between the particle volume andthe true volume, measured by mercury intrusion
17、 and heliumpycnometry, respectively. The particle volume is determinedby mercury intrusion at ambient pressure and the true volumeis determined by helium displacement at pressures aboveambient.5. Significance and Use5.1 This test method provides for the measurement ofvolume of pores that are in the
18、range of catalytic importanceand possibly for adsorption processes. This test method re-quires the use of mercury in order to perform the measure-ments.6. Apparatus6.1 For Mercury Intrusion:6.1.1 Chamber, capable of holding the sample cell (com-monly referred to as a penetrometer), which contains th
19、esample. This chamber must be capable of being evacuated andcontain enough mercury to fill the penetrometer.6.1.2 Glass Sample Cell (penetrometer), having a wide baseand narrow bore stem. If the sample is powder, the penetrom-eter should have a provision in the base to prevent fine particlesfrom pas
20、sing into the stem when the cell is evacuated. Thepenetrometer must have the capability of being sealed.6.1.3 Vacuum Pump, capable of attaining pressures of lessthan 0.05 torr.6.1.4 Valve, for choosing vacuum and vent, for evacuationof the sample cell and filling the sample cell, respectively.6.1.5
21、Valve, for rapid evacuation or venting of the system.6.1.6 Valve, for controlled evacuation or venting.6.1.7 Cold Trap, or other method or device to preventmercury vapor from being vented into the laboratory throughthe vacuum pump and to prevent contaminants from enteringthe vacuum pump.6.1.8 Pressu
22、re-Measuring Device, capable of reading in therange 0 to 1000 torr or higher.6.1.9 Balance, measuring to the nearest 1 mg (60.001 g).6.2 For Mercury Intrusion with a BuretteA schematicdiagram of the burette is shown in Fig. 1. It has the followingfeatures:6.2.1 Glass Sample Cell, with a needle valve
23、 suitable forhandling mercury. The tip, which is submerged in the mercuryreservoir, should be narrow enough so as to prevent drops ofmercury from becoming lost if the reservoir is removed forweighing.6.2.2 Burette, a calibrated narrow bore tube ending in acurved tip in the sample cell to prevent fin
24、e particles frompassing into the burette. There is a clear mark on the burette at23 cm above the curved tip.6.2.3 Manifold, with a splash bulb and appropriate needlevalves for choosing either vacuum or vent.6.2.4 Mercury Reservoir with Lid, capable of containing theamount of mercury necessary to fil
25、l the sample cell and burettewhile the tip of the sample cell valve is still submerged inmercury. A weighing bottle of 5 cm diameter and 3 cm heightis suitable.6.2.5 Vacuum Pump, capable of attaining pressures of 0.05torr.6.2.6 Cold Trap, or other method or device to preventmercury vapor from being
26、vented into the laboratory throughthe vacuum pump and to prevent contaminants from enteringthe vacuum pump.6.3 For Helium PycnometryA schematic diagram of thepycnometer apparatus is shown in Fig. 2. It should be con-structed from metal and have the following features:6.3.1 Sample Cell, having a volu
27、me suitable for the desiredsample size and calibrated to the nearest 0.1 cm3. This volumeis indicated in Fig. 2.6.3.2 Reference Volume (VR), a precisely calibrated volumeknown to the nearest 0.02 cm3.6.3.3 Pressure Transducer, (0 to 25 psig or 0 to 172.3 kPa)with minimum volume displacement and line
28、ar within 0.1 %.FIG. 1 Schematic Diagram of BuretteD6761 07 (2012)26.3.4 Pressure Relief Valve, set to 25 psig (172.3 kPa), toavoid overpressurization of the transducer.6.3.5 Filter, to prevent powder from contaminating thepressure transducer.6.3.6 Input Flow Control Valves, to control pressurizatio
29、n.6.3.7 Output Flow Control Valves, to vent the gas.6.3.8 Valve, to connect the reference volume to the samplecell.6.3.9 Non-Porous Calibration Standard, (preferably stain-less steel) of known volume which fills14 to23 of the samplecup.6.3.10 Digital Meter, for reading the pressure to 0.001 psig(6.8
30、9 Pa) from the transducer.6.3.11 Sample Cell Cover, with O-ring seal.7. Reagents7.1 For Mercury Intrusion:7.1.1 Mercury, triply distilled.7.2 For Helium Pycnometry:7.2.1 Helium Gas, a cylinder of helium gas at least 99.9 %pure, with regulator.8. Hazards8.1 Samples that have been exposed to mercury a
31、re danger-ous. Apply the precautions given by the following:8.1.1 Mercury is a hazardous substance that can causeillness and death. Mercury can also be absorbed through theskin; avoid direct contact.8.1.2 Always store in closed containers to control its evapo-ration, and use it only in well-ventilat
32、ed rooms.8.1.3 Wash hands immediately after any operation involvingmercury.8.1.4 Exercise extreme care to avoid spilling mercury. Cleanup spills immediately using procedures recommended explic-itly for mercury.8.1.5 Recycling of waste mercury is recommended and to beconducted in accordance with loca
33、l government hazardouswaste regulations. Disposal of waste mercury and mercurycontaminated materials should be performed as mandated bylocal government hazardous waste regulations.9. Procedure9.1 For Mercury Intrusion Instruments:9.1.1 Weigh the empty penetrometer with sealing device inplace (WC).9.
34、1.2 Place the empty penetrometer in the low pressure portof the instrument, seal it, and follow the manufacturersrecommendations for evacuating the penetrometer and subse-quently filling it with mercury.9.1.3 When the penetrometer is completely filled withmercury, follow the manufacturers recommenda
35、tions forbringing the low pressure port to atmospheric pressure.9.1.4 When the low pressure port is again at atmosphericpressure, unseal the penetrometer and remove it from the lowpressure port. (WarningAs the penetrometer is removedfrom the low pressure port, be sure to tilt the bulb end of thepene
36、trometer down and the stem up, so mercury does not spillfrom the open stem end.)9.1.5 Weigh the mercury-filled penetrometer using an ana-lytical balance, and record this weight as (W8C). Empty thepenetrometer, dispose of the mercury in an approved container,and clean the penetrometer.9.1.6 Weigh the
37、 sample using an analytical balance. Recordthis as (W).9.1.7 Hold the penetrometer with the stem down and care-fully pour the sample into the bulb. (WarningWhen pouringpowders into the bulb, place your finger over the stem openingin the center of the bulb so that powder does not enter the stem.Large
38、 granules or chunks may be loaded with forceps. Touch-ing such pieces with the fingers should be avoided as skin oilsmay be transferred that can slightly alter the results or createevacuation problems.)9.1.8 Seal the penetrometer, being careful to avoid usingexcessive sealing grease.9.1.9 Weigh the
39、sealed penetrometer with the sample usingan analytical balance. Record this weight as (Ws).9.1.10 Place the penetrometer assembly with the sample inthe low pressure port of the instrument, seal it, and follow themanufacturers recommendations for evacuating the penetrom-eter and performing a low pres
40、sure analysis.9.1.11 When the low pressure run is complete, bring the lowpressure chamber back to atmospheric pressure and follow themanufacturers recommendations for removing the penetrom-eter from the low pressure port. (WarningAs the penetrom-eter is removed from the low pressure port, be sure to
41、 tilt thebulb end of the penetrometer down and the stem end up, somercury does not spill from the open stem end.)9.1.12 Weigh the sealed penetrometer with sample and filledwith mercury using an analytical balance. Record this weightas (W8S).9.2 For Mercury Intrusion Using the Burette Method:9.2.1 Pl
42、ace a coolant (liquid nitrogen or dry ice-acetonemixture) around the cold trap.9.2.2 Close the vent valve (A) and the sample cell valve (C),and evacuate the burette by opening the vacuum valve (B).9.2.3 Slowly open the sample cell valve and allow mercuryto fill the sample cell and the burette. Close
43、 the sample cellvalve (C) when the mercury level is 1 to 2 cm above the 23 cmmark. Open the vent valve (A) to allow ambient pressure in theburette. Adjust the mercury level in the burette to the 23 cmmark by slowly draining mercury via the sample cell valve (C)into the mercury reservoir.9.2.4 Place
44、a lid on the mercury reservoir and weigh it usingan analytical balance (Wb8).9.2.5 Drain the mercury from the burette and the sample cellinto the mercury reservoir and close the sample cell valve (C).FIG. 2 Pycnometer ApparatusD6761 07 (2012)39.2.6 Weigh the catalyst sample using an analytical balan
45、ceand record this weight as (W). Place this sample in the samplecell. Connect the sample cell to the burette and place themercury reservoir under the sample cell with the tip of thesample cell valve (C) submerged in mercury.9.2.7 Evacuate the burette and sample cell with sample byclosing the vent va
46、lve (A) and slowly opening the vacuumvalve (B) in order to prevent fine particles from entering intothe burette.9.2.8 Allow the sample to degas at 0.05 torr or lower for aminimum of 30 min before filling with mercury.9.2.9 Repeat steps 9.2.2 through 9.2.4 giving the weight ofthe mercury reservoir (W
47、b).9.2.10 Drain the mercury from the burette and the samplecell into the mercury reservoir, taking care that afterwards noparticles of the sample are floating on the mercury in thereservoir.9.3 For Helium Pycnometry:9.3.1 Calibration ProcedureTo determine the cell andreference volumes of the pycnome
48、ter.9.3.1.1 Place an empty sample cup in the sample cell holderand seal according to the manufacturers suggested procedure.9.3.1.2 Open the output valves and zero the output display.9.3.1.3 Turn the selector valve to exclude the referencevolume.9.3.1.4 Close the vent valve.9.3.1.5 Open the input flo
49、w control valve and pressurize thesample cell to between 15 and 19 psig (103.4 and 130.9 kPa)using the input valve to control the rate of pressurization. Whenthe desired pressure is reached, close the input valve to stop theflow of gas into the sample chamber.9.3.1.6 Record the pressure on the digital display. This valueis P81.9.3.1.7 Turn the selector valve to include the referencevolume.9.3.1.8 Record the displayed pressure reading as P82.9.3.1.9 Vent the pressure using the vent valve.9.3.1.10 Place the calibration standard cylinder into thesample cup and
