ASTM D5153-2010(2016) Standard Test Method for Palladium in Molecular Sieve Catalyst by Atomic Absorption《采用原子吸收法测定分子筛催化剂中钯的标准试验方法》.pdf

1、Designation: D5153 10 (Reapproved 2016)Standard Test Method forPalladium in Molecular Sieve Catalyst by AtomicAbsorption1This standard is issued under the fixed designation D5153; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the

2、 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 palladiumin molecular sieve-containing fresh catalysts with abou

3、t 0.5weight % of palladium.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 thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this

4、 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:2D1193 Specification for Reagent WaterE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Termin

5、ology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodD7442 Practice for Sample Preparation of Fluid CatalyticCracking Catalysts and Zeolites for ElementalAnalysis byInductively Coupled Plasma Atomic Emission Spectros-

6、copy2.2 U.S. Federal Specification:Federal Spec. NNN-P-395C Tolerance for Class A Pipets33. Summary of Test Method3.1 The test sample is treated with a mixture of sulfuric andhydrofluoric acids. Upon dissolution, the excess hydrofluoricacid is expelled. Aqua regia and lanthanum chloride are addedand

7、 the solution is diluted to a specific volume. Palladiumconcentration is determined by atomic absorption spectropho-tometry. Absorbance of the samples is bracketed using a set ofnarrow range, matrix matched standards. A second sample,taken at the same time as the analysis sample, is used todetermine

8、 loss on 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 precious metals other than palladium.5. Apparatus5.1 Analytical Balance, ca

9、pable of weighing to nearest0.1 mg.5.2 Atomic Absorption Spectrophotometer.5.3 Beakers, TFE-fluorocarbon, 100-mL.5.4 Crucibles, porcelain, 10-mL.5.5 Crucible Cover, porcelain, for 10-mL crucible.5.6 Desiccator.5.7 Flasks, Erlenmeyer, 2000-mL.5.8 Graduated Cylinders, glass, 5-mL, 10-mL, 25-mL,50-mL,

10、250-mL, 500-mL, 1000-mL.5.9 Graduated Cylinder, plastic, 10-mL.5.10 Hot Plate.5.11 Muffle Furnace, electrically heated, capable of 1000C.5.12 Pipets, 4-mL, 6-mL, 8-mL, 10-mL.5.13 Volumetric Flasks, 100-mL, 500-mL.5.14 Watch Glasses, TFE-fluorocarbon, for 100-mL beaker.5.15 Weighing Papers.6. Reagent

11、s and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended that1This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.03 on ChemicalComposition.Current

12、edition approved Jan. 1, 2016. Published January 2016. Originallyapproved in 1991. Last previous edition approved in 2010 as D515310. DOI:10.1520/D5153-10R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of A

13、STMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh

14、ohocken, PA 19428-2959. United States1all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused provided it is first ascertained that the reagent is ofsufficiently high p

15、urity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Specification D1193.6.3 Hydrochloric Acid, concentrated, 36.538.0 wt. % or 12M, sp gr 1.18.6.4 Hydrofluo

16、ric Acid, concentrated, 48.051.0 wt. % or28.9 M, sp gr 1.17.NOTE 1Refer to Section 8 of Practice D7442-08 for hazards associ-ated with handling of acids.6.5 Nitric Acid, concentrated, 69.071.0 wt. % or 15.7 M, spgr 1.41.6.6 Sulfuric Acid, concentrated, 95.098.0 wt. % or 18 M,sp gr 1.84.6.7 Aluminum

17、Oxide (Al2O3).6.8 Lanthanum Chloride (LaCl37H2O).6.9 Palladium Wire, 99.99 %.6.10 Aqua RegiaMix three parts by volume of concen-trated hydrochloric acid (12 M) and one part by volume ofconcentrated nitric acid (15.7 M) immediately before use.6.11 Sulfuric Acid, 15.816.3 wt. % or 3M. Cautiously add25

18、0 mL of concentrated sulfuric acid (18 M) to 1250 mL ofwatermix well and allow to cool.6.12 Palladium Standard Solution, 500 mg/L. Dissolve0.2500 6 0.0001 g of palladium wire (99.99 %) in 25 mL ofaqua regia. Evaporate the solution to dryness on a steam bath.Dissolve the remaining salts by addition o

19、f 25 mL of concen-trated hydrochloric acid (12 M) and 25 mL of distilled water.Transfer the solution to a 500 mL volumetric flask and dilute tovolume when cool.NOTE 2A commercially available atomic absorption palladium refer-ence solution may be used if it is known to be reliable.6.13 Lanthanum Chlo

20、ride SolutionDissolve 25.5 g oflanthanum chloride (LaCl37H2O) in distilled water, dilute to100 mL and mix well. This solution serves as an ionizationsuppressor in atomic absorption.6.14 Desiccant, molecular sieve, type 4A.7. Procedure7.1 Preparation of Calibration Standards:7.1.1 If the concentratio

21、n of aluminum oxide in the sampleis unknown, digest a representative sample in acid and deter-mine the aluminum concentration by atomic absorption spec-trophotometry.7.1.2 Transfer 30 mL of sulfuric acid (3M) to five TFE-fluorocarbon beakers.7.1.3 To each beaker add the equivalent weight of aluminum

22、oxide that would be present in 0.8000 g of sample asdetermined in 7.1.1.NOTE 3If it is available, 0.800 g of catalyst base material may besubstituted for the aluminum oxide.7.1.4 Transfer 0, 4, 6, 8 and 10 mL of the 500 mg/Lpalladium standard to the five TFE-fluorocarbon beakers.7.1.5 Add 10 mL of c

23、oncentrated hydrofluoric acid to eachbeaker.7.1.6 Cover the beakers with TFE-fluorocarbon lids anddigest on a hot plate at medium heat until all solid material isin solution (including any brown stains that may appear on thebeaker walls) and light fumes are evolved.NOTE 4If brown stains do not redis

24、solve, discard sample and prepareagain.7.1.7 Cool the solutions. Dilute to 70 mL with distilledwater. Add 10 mL of aqua regia. Boil gently for a few minuteson a hot plate.7.1.8 When the solution is cool, transfer quantitatively to a500-mL volumetric flask.7.1.9 Add 5 mL of the lanthanum chloride sol

25、ution to eachflask. Dilute to volume when the solution has reached roomtemperature.7.1.10 The concentration of palladium will be 0, 4, 6, 8 and10 mg/L.NOTE 5The standard solutions are stable for two months.7.2 WeighingPrepare a carefully riffled, finely groundsample of ambient-equilibrated catalyst.

26、 For example, thesample could be thinly spread on filter paper and exposed toroom conditions for 16 h. The test method requires 7 to 10 g ofsample. Samples for LOI and analysis shall be weighed at thesame time.7.2.1 For determination of percent loss on ignition at1000C, ignite a porcelain crucible w

27、ith lid at 1000C for atleast 30 min, place in desiccator to cool and weigh to nearest0.1 mg. Transfer approximately 2.0 g of ambient-equilibratedsample to the crucible and weigh to the nearest 0.1 mg with thelid in place. Duplicate loss on ignition measurements arerequired to determine the average L

28、OI noted in the finalcalculations.7.2.2 For determination of palladium, transfer in triplicate0.75 to 0.85 g of sample, weighed to the nearest 0.1 mg, intoa 100-mL TFE-fluorocarbon beaker.7.3 Loss on Ignition:7.3.1 Place the porcelain crucible containing the test samplein a muffle furnace maintained

29、 at 450C and heat for at least 30min.7.3.2 Transfer the crucible to a muffle furnace maintained at1000C and heat for 1.5 h to constant weight.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted b

30、y the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D5153 10 (2016)27.3.3 Remove the crucible from the furnace, place in des-ic

31、cator to cool, and weigh to nearest 0.1 mg.7.3.4 Calculate weight percent loss on ignition at 1000C asfollows:Weight % LOI 5I 2 F!I3100 (1)where:I = initial sample weight, andF = final sample weight.7.4 Preparation of Test Sample for Atomic Absorption:7.4.1 Cautiously add 30 mL of sulfuric acid (3M)

32、 mixture tothe test sample in the TFE-fluorocarbon beaker. Add 10 mL ofconcentrated hydrofluoric acid.7.4.2 Cover the beakers with TFE-fluorocarbon lids anddigest the samples on a hot plate at medium heat until all solidmaterial is in solution and light fumes are evolved.7.4.3 Allow the solutions to

33、 cool. Dilute to 70 mL withdistilled water. Add 10 mL of aqua regia. Boil gently for a fewminutes.7.4.4 Allow the solutions to cool. Transfer quantitatively to500 mL volumetric flasks.Add 5 mL of the lanthanum chloridesolution.7.4.5 Dilute to volume when solutions have cooled to roomtemperature.7.4.

34、6 Analyze the sample with an atomic absorption spec-trophotometer in the absorbance mode at 247.6 nm usingair-acetylene flame with background correction.7.4.7 Bracket the sample reading between appropriate cali-bration standards.NOTE 6Make certain that samples and standards are on the linearportion

35、of the calibration curve. If a sample falls on the nonlinear portionof the curve, make appropriate dilution and matrix adjustments. Checkzero setting before each standard and sample reading using the 0 mg/Lstandard.8. Calculation of Results8.1 Calculate the weight percent of palladium in the testsam

36、ple on a 1000C ignited basis as follows:8.1.1 Method 1Plot the absorbance of the standards versusthe concentration of palladium in the standards. Determine theconcentration of palladium in the sample using the calibrationcurve.8.1.2 Method 2The concentration of palladium in thesample solutions may b

37、e calculated as follows:CS 5AS 2 AL! 3 CH 2 CL!AH 2 AL!1CL (2)where:CS = mg/L of palladium in sample solution,AS = absorbance of the sample,AL = absorbance of lower standard,AH = absorbance of higher standard,CL = mg/L of palladium in the lower standard, andCH = mg/L of palladium in the higher stand

38、ard.8.1.3 The concentration of palladium in the sample iscalculated as follows:Palladium, % 5CSF1.00 2% LOI100G3W 320(3)where:CS = mg/L of palladium in sample solution,W = grams of sample, andLOI = average of duplicate loss on ignitions.9. Precision and Bias59.1 Test ProgramAn interlaboratory study

39、was conductedin which the weight % palladium (volatile free basis) wasmeasured in one separate test material in eight separatelaboratories. Practice E691, modified for non-uniform datasets, was followed for the data reduction. Analysis details arein the research report.9.2 PrecisionPairs of test res

40、ults obtained by a proceduresimilar to that described in the study are expected to differ inabsolute value by less than 2.772 S, where 2.772 S is the 95 %probability interval limit on the difference between two testresults, and S is the appropriate estimate of standard deviation.Definitions and usag

41、e are given in Terminology E456 andPractice E177, respectively.Test Result(Consensus Mean)weight %95 % RepeatabilityInterval(Within Laboratory)weight %95 % ReproducibilityInterval(Between Laboratories)weight %0.5406 0.005 (0.95 % of mean) 0.021 (3.94 % of mean)9.3 BiasThis test method is without kno

42、wn bias.10. Keywords10.1 atomic absorption; molecular sieve; molecular sievecatalyst; palladium5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D32-1034.D5153 10 (2016)3ASTM International takes no position respecting the validity

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