1、Designation: D6761 07 (Reapproved 2012)D6761 17Standard 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 th
2、e 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 determination of the total pore volume of catalysts and ca
3、talyst carriers, that is, the volume ofpores having pore diameter between approximately 14 m and 0.4 nm (4 ).1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 WARNINGMercury has been designated by many regulatory agencie
4、s as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Cautionshould be taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet(M
5、SDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional information. Users should be awarethat selling mercury and/or mercury containing products into your state or country may be prohibited by law.1.4 This standard does not purport to address all of the safety concerns, if
6、any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use. Specific hazard statements are given in Section 8. Warning state
7、ments are givenin 9.1.4, 9.1.7, and 9.1.11.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World
8、Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3766 Terminology Relating to Catalysts and CatalysisE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice fo
9、r Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 particle volumethe volume of a particle including pores into which mercury cannot penetrate at ambient pressure(smaller than approximately 14 m diameter pore mouth).3.1.2 true volumet
10、he volume of a particle, including pores, into which helium cannot penetrate (smaller than aboutapproximately 0.4 nm (4 ) diameter pore mouth).3.1.3 Other definitions and terms used in this test method are defined in Terminology D3766.3.2 Symbols for Mercury Intrusion:W = mass of sample1 This test m
11、ethod is under the jurisdiction of ASTM Committee D32 on Catalysts and is the direct responsibility of Subcommittee D32.02 on Physical-MechanicalProperties.Current edition approved May 1, 2012Oct. 1, 2017. Published July 2012October 2017. Originally approved in 2002. Last previous edition approved i
12、n 20072012 asD6761D676107(2012).07. DOI: 10.1520/D6761-07R12.10.1520/D6761-17.2 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
13、the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication 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
14、consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Wc = mass of sealed empty sampl
15、e cellWC = mass of sealed sample cell filled with mercuryWs = mass of sealed sample cell with sampleWS = mass of sealed sample cell with sample filled with mercuryVHgC = volume of mercury in empty sample cell (volume of sample cell)VHgS = volume of mercury in cell with sampleVSHg = sample volume, cm
16、3VHg = specific sample volumeVP = particle volumeWb = weight mercury reservoir after filling burette with sampleWb = mass of mercury reservoir after filling burette without sample3.3 Symbols for Helium Pycnometry:VC = volume of sample cell and associated tubing, cm3VR = reference volume, cm3VSHe = s
17、ample volume, cm3VCyl = volume of calibration cylinder, cm3VSTD = volume of calibration standard, cm3VHe = specific sample volumeP1 = pressure in empty sample cell, psig or pascalsP2 = pressure in empty sample cell, after the reference volume has been included in the system, psig or pascalsP1 = pres
18、sure in sample cell with sample or calibration standard before the reference volume has been included in the system,psig or pascalsP2 = pressure with sample or calibration standard in the sample cell, after the reference volume has been included in thesystem, psig or pascalsW1 = tare weight of sampl
19、e 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 is determined as the difference between the particle volume and thetrue volume, measured by mercury intrusion and hel
20、ium pycnometry, respectively. The particle volume is determined by mercuryintrusion at ambient pressure and the true volume is determined by helium displacement at pressures above ambient.5. Significance and Use5.1 This test method provides for the measurement of volume of pores that are in the rang
21、e of catalytic importance and possiblyfor adsorption processes. This test method requires the use of mercury in order to perform the measurements.6. Apparatus6.1 For Mercury Intrusion:6.1.1 Chamber, capable of holding the sample cell (commonly referred to as a penetrometer), which contains the sampl
22、e. Thischamber must be capable of being evacuated and contain enough mercury to fill the penetrometer.6.1.2 Glass Sample Cell (penetrometer), having a wide base and narrow bore stem. If the sample is powder, the penetrometershould have a provision in the base to prevent fine particles from passing i
23、nto 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 less than 0.05 torr.6.1.4 Valve, for choosing vacuum and vent, for evacuation of the sample cell and filling the sample cell, respectively.6.1.5 Valv
24、e, 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 prevent mercury vapor from being vented into the laboratory through the vacuumpump and to prevent contaminants from entering the vacuum pump.6.1.8 Pressure
25、-Measuring Device, capable of reading in the range 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 schematic diagram of the burette is shown in Fig. 1. It has the following features:6.2.1 Glass Sample Cell, with a needle valv
26、e suitable for handling mercury. The tip, which is submerged in the mercuryreservoir, should be narrow enough so as to prevent drops of mercury from becoming lost if the reservoir is removed for weighing.6.2.2 Burette, a calibrated narrow bore tube ending in a curved tip in the sample cell to preven
27、t fine particles from passing intothe burette. There is a clear mark on the burette at 23 cm above the curved tip.D6761 1726.2.3 Manifold, with a splash bulb and appropriate needle valves for choosing either vacuum or vent.6.2.4 Mercury Reservoir with Lid, capable of containing the amount of mercury
28、 necessary to fill the sample cell and burettewhile the tip of the sample cell valve is still submerged in mercury.Aweighing bottle of 5 cm diameter and 3 cm height is suitable.6.2.5 Vacuum Pump, capable of attaining pressures of 0.05 torr.6.2.6 Cold Trap, or other method or device to prevent mercur
29、y vapor from being vented into the laboratory through the vacuumpump and to prevent contaminants from entering the vacuum pump.6.3 For Helium PycnometryA schematic diagram of the pycnometer apparatus is shown in Fig. 2. It should be constructedfrom metal and have the following features:6.3.1 Sample
30、Cell, having a volume suitable for the desired sample size and calibrated to the nearest 0.1 cm3. This volume isindicated in Fig. 2.6.3.2 Reference Volume (VR), a precisely calibrated volume known to the nearest 0.02 cm3.6.3.3 Pressure Transducer, (0 to 25 psig or 0 to 172.3 kPa) with minimum volume
31、 displacement and linear within 0.1 %.6.3.4 Pressure Relief Valve, set to 25 psig (172.3 kPa), to avoid overpressurization of the transducer.6.3.5 Filter, to prevent powder from contaminating the pressure transducer.6.3.6 Input Flow Control Valves, to control pressurization.6.3.7 Output Flow Control
32、 Valves, to vent the gas.6.3.8 Valve, to connect the reference volume to the sample cell.6.3.9 Non-Porous Calibration Standard, (preferably stainless steel) of known volume which fills 14 to 23 of the sample cup.6.3.10 Digital Meter, for reading the pressure to 0.001 psig (6.89 Pa) from the transduc
33、er.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 are dangerous. Apply th
34、e precautions given by the following:FIG. 1 Schematic Diagram of BuretteD6761 1738.1.1 Mercury is a hazardous substance that can cause illness and death. Mercury can also be absorbed through the skin; avoiddirect contact.8.1.2 Always store in closed containers to control its evaporation, and use it
35、only in a fume hood or in well-ventilated rooms.8.1.3 Wash hands immediately after any operation involving mercury.8.1.4 Exercise extreme care to avoid spilling mercury. Clean up spills immediately using procedures recommended explicitlyfor mercury.8.1.5 Recycling of waste mercury is recommended and
36、 to be conducted in accordance with local government hazardous wasteregulations. Disposal of waste mercury and mercury contaminated materials should be performed as mandated by local governmenthazardous waste regulations.9. Procedure9.1 For Mercury Intrusion Instruments:9.1.1 Weigh the empty penetro
37、meter with sealing device in place (WC).9.1.2 Place the empty penetrometer in the low pressure port of the instrument, seal it, and follow the manufacturersrecommendations for evacuating the penetrometer and subsequently filling it with mercury.9.1.3 When the penetrometer is completely filled with m
38、ercury, follow the manufacturers recommendations for bringing thelow pressure port to atmospheric pressure.9.1.4 When the low pressure port is again at atmospheric pressure, unseal the penetrometer and remove it from the low pressureport. (WarningAs the penetrometer is removed from the low pressure
39、port, be sure to tilt the bulb end of the penetrometer downand the stem up, so mercury does not spill from the open stem end.)9.1.5 Weigh the mercury-filled penetrometer using an analytical balance, and record this weight as (WC). Empty thepenetrometer, dispose of the mercury in an approved containe
40、r, and clean the penetrometer.9.1.6 Weigh the sample using an analytical balance. Record this as (W).9.1.7 Hold the penetrometer with the stem down and carefully pour the sample into the bulb. (WarningWhen pouringpowders into the bulb, place your finger over the stem opening in the center of the bul
41、b so that powder does not enter the stem.Large granules or chunks may be loaded with forceps. Touching such pieces with the fingers should be avoided as skin oils maybe transferred that can slightly alter the results or create evacuation problems.)9.1.8 Seal the penetrometer, being careful to avoid
42、using excessive sealing grease.9.1.9 Weigh the sealed penetrometer with the sample using an analytical balance. Record this weight as (Ws).9.1.10 Place the penetrometer assembly with the sample in the low pressure port of the instrument, seal it, and follow themanufacturers recommendations for evacu
43、ating the penetrometer and performing a low pressure analysis.9.1.11 When the low pressure run is complete, bring the low pressure chamber back to atmospheric pressure and follow themanufacturers recommendations for removing the penetrometer from the low pressure port. (WarningAs the penetrometer is
44、removed from the low pressure port, be sure to tilt the bulb end of the penetrometer down and the stem end up, so mercury doesnot spill from the open stem end.)9.1.12 Weigh the sealed penetrometer with sample and filled with mercury using an analytical balance. Record this weight as(WS).9.2 For Merc
45、ury Intrusion Using the Burette Method:9.2.1 Place a coolant (liquid nitrogen or dry ice-acetone mixture) 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 merc
46、ury to fill the sample cell and the burette. Close the sample cell valve(C) when the mercury level is 1 to 2 cm above the 23 cm mark. Open the vent valve (A) to allow ambient pressure in the burette.Adjust the mercury level in the burette to the 23 cm mark by slowly draining mercury via the sample c
47、ell valve (C) into the mercuryreservoir.9.2.4 Place a lid on the mercury reservoir and weigh it using an analytical balance (Wb).9.2.5 Drain the mercury from the burette and the sample cell into the mercury reservoir and close the sample cell valve (C).9.2.6 Weigh the catalyst sample using an analyt
48、ical balance and record this weight as (W). Place this sample in the sample cell.Connect the sample cell to the burette and place the mercury reservoir under the sample cell with the tip of the sample cell valve(C) submerged in mercury.FIG. 2 Pycnometer ApparatusD6761 1749.2.7 Evacuate the burette a
49、nd sample cell with sample by closing the vent valve (A) and slowly opening the vacuum valve (B)in order to prevent fine particles from entering into the burette.9.2.8 Allow the sample to degas at 0.05 torr or lower for a minimum of 30 min before filling with mercury.9.2.9 Repeat steps 9.2.2 through 9.2.4 giving the weight of the mercury reservoir (Wb).9.2.10 Drain the mercury from the burette and the sample cell into the mercury reservoir, taking care that afterwards no particlesof the sample are floating on the mercury in the reservoir.9.3 For Hel
