1、Designation:D478210Standard Test Method forPalladium in Molecular Sieve Catalyst by Wet Chemistry1This standard is issued under the fixed designation D4782;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A n
2、umber 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 palladiumin molecular sieve-containing fresh catalysts with about 0.5weight%of palladium.1.2 Th
3、e 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 any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate s
4、afety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD7442 Practice for Sample Preparation of Fluid CatalyticCracking Catalysts and Zeolites for ElementalAnalysis byInductivel
5、y Coupled Plasma Atomic Emission Spectros-copyE177 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 of a Test Method3.Summary of Test Method3.1 The te
6、st sample is treated with hydrofluoric acid andevaporated to dryness to remove silica;the residue is fusedwith potassium pyrosulfate,and the cooled melt is dissolved in4%H2SO4.A measured excess of 0.01 N potassium iodide(KI)is added to precipitate palladium as palladium iodide(PdI2).The precipitate
7、is filtered and washed,and a smallamount of sodium sulfite is added to the filtrate to reduce anyfree iodine to iodide.The excess iodide is titrated with 0.01 NAgNO3potentiometrically,using a silver electrode versus acalomel electrode.A second sample taken at the same time isused to determine loss o
8、n ignition.4.Significance and Use4.1 This test method provides a means of determining thepalladium content in fresh catalysts containing molecularsieves.4.2 This test method is not intended to cover samplescontaining metals other than palladium.5.Apparatus5.1 pH Meter with Millivolt Scale or automat
9、ic recordingtitrator.5.2 Silver-Sulfide Electrode.5.3 Silver-Silver Chloride Double Junction reference elec-trode with 10%KNO3in the outer chamber.5.4 Fisher Burner.5.5 Low-Temperature Muffle Furnace,450C.5.6 High-Temperature Muffle Furnace,1000C.5.7 Hot-Plate,with sand bath as a preferred option.5.
10、8 Magnetic Stirrer and TFE-Fluorocarbon-Coated Stir-ring Bars.5.9 Burets,25-mL,with 0.1-mL graduations or an equiva-lent.5.10 Volumetric Flasks,1000-mL.5.11 High-Silica Beakers,400-mL,with disposable boro-silicate beakers as an option.Alternatively,a petri dish can beused for the fusion step,with po
11、lypropylene beakers beingused thereafter.5.12 Watch Glasses,preferably ribbed,87 mm.5.13 Analytical Balance,capable of weighing to nearest 0.1mg.5.14 Weighing Papers.5.15 Porcelain Crucibles,10-mL.5.16 Graduated Cylinders,5-mL,10-mL,25-mL,100-mL.1This test method is under the jurisdiction of ASTM Co
12、mmittee D32 onCatalysts and is the direct responsibility of Subcommittee D32.03 on ChemicalComposition.Current edition approved April 1,2010.Published May 2010.Originallyapproved in 1988.Last previous edition approved in 2004 as D478204.DOI:10.1520/D4782-10.2For referenced ASTM standards,visit the A
13、STM 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 website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States
14、1 5.17 Filter Paper,Whatman No.40,11 cm.5.18 Funnel,filter.5.19 Desiccator.5.20 Crucible Cover,porcelain.6.Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of t
15、he Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of Wa
16、terUnless otherwise indicated,referencesto water shall be understood to mean reagent water as definedby Specification D1193.6.3 Desiccant Molecular Sieve,type 4A.6.4 Filter Paper Pulp.NOTE1Refer to Section 8 on Hazards in Practice D7442 for hazardsassociated with handling of acids.6.5 Hydrofluoric Acid(HF),48%.6.6 Potassium Iodide Solution,0.01 NDissolve 1.66 g ofpotassium iodide(KI)in distilled water,dilute to 1000 mL,andmix well.6.7 Potassium Pyrosulfate(K2S2O8).6.8 Silver Nitrate Solution,0.0