1、Designation: D 5153 04Standard Test Method forPalladium in Molecular Sieve Catalyst by AtomicAbsorption1This standard is issued under the fixed designation D 5153; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 % o
3、f palladium.1.2 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.
4、Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 456 Terminology Relating to Quality and StatisticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Metho
5、d2.2 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 th
6、e 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 lo
7、ss 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, capab
8、le of weighing to nearest 0.1mg.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, 25
9、0-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. Reagents
10、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 the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Oth
11、er 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.1This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32
12、.03 on ChemicalComposition.Current edition approved April 1, 2004. Published April 2004. Originallyapproved in 1991. Last previous edition approved in 1997 as D 515391(1997).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For
13、Annual Book of ASTMStandards 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 19111-5098.4Reagent Chemicals, American Chemical Society Specifications
14、, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by 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
15、. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Specification D 1193.6.3 Hydrochloric aci
16、d, concentrated, 36.538.0 wt. % or 12M, sp gr 1.18.6.4 Hydrofluoric acid, concentrated, 48.051.0 wt. % or28.9 M, sp gr 1.17.6.5 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, spgr 1.84.6.7 Aluminum Oxide (Al2O3).6.8 Lanthanum C
17、hloride (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 3MCautiously add250 mL of concentrated sulfuric a
18、cid (18 M) to 1250 mL ofwatermix well and allow to cool.6.12 Palladium Standard Solution, 500 mg/LDissolve0.2500 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 of 25 mL of concen-trated hydrochl
19、oric acid (12 M) and 25 mL of distilled water.Transfer the solution to a 500 mL volumetric flask and dilute tovolume when cool.NOTE 1A commercially available atomic absorption palladium refer-ence solution may be used if it is known to be reliable.6.13 Lanthanum Chloride SolutionDissolve 25.5 g ofla
20、nthanum 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 concentration of aluminum oxide in the sample
21、is 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 aluminumoxide that would be present in 0.
22、8000 g of sample asdetermined in 7.1.1.NOTE 2If 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 concentrated hydrofluoric acid to
23、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 3If brown stains do not redissolve, discard sample and prepare
24、again.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 solution to eachflask. Dilute to vol
25、ume when the solution has reached roomtemperature.7.1.10 The concentration of palladium will be 0, 4, 6, 8 and10 mg/L.NOTE 4The standard solutions are stable for two months.7.2 WeighingPrepare a carefully riffled, finely groundsample of ambient-equilibrated catalyst. For example, thesample could be
26、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 with lid at 1000C for atleast 30 m
27、in, 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 LOI noted in the finalcalculations
28、.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 at 450C and heat for at least 30
29、min.7.3.2 Transfer the crucible to a muffle furnace maintained at1000C and heat for 1.5 h to constant weight.7.3.3 Remove the crucible from the furnace, place in des-iccator 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!I3
30、 100 (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) mixture tothe test sample in the TFE-fluorocarbon beaker. Add 10 mL ofconcentrated hydrofluoric acid.7.4.2 Cover the beakers with
31、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 cool. Dilute to 70 mL withdistilled water. Add 10 mL of aqua regia. Boil gently for a fewminutes.D51530427.4.4 Allow the solutions
32、 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.7.4.6 Analyze the sample with an atomic absorption spec-trophotometer in the absorbance mode at 247.6 nm usingair-acetylene fl
33、ame with background correction.7.4.7 Bracket the sample reading between appropriate cali-bration standards.NOTE 5Make certain that samples and standards are on the linearportion of the calibration curve. If a sample falls on the nonlinear portionof the curve, make appropriate dilution and matrix adj
34、ustments. 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 testsample on a 1000C ignited basis as follows:8.1.1 Method 1Plot the absorbance of the standards ver-sus the concentration of pa
35、lladium in the standards. Determinethe concentration of palladium in the sample using the calibra-tion curve.8.1.2 Method 2The concentration of palladium in thesample solutions may be calculated as follows:CS 5AS 2 AL! 3 CH 2 CL!AH 2 AL!1 CL (2)where:CS = mg/L of palladium in sample solution,AS = ab
36、sorbance 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 standard.8.1.3 The concentration of palladium in the sample iscalculated as follows:Palladium, % 5CSF1.00 2% LOI100G3 W 3
37、20(3)where:CS = mg/L of palladium in sample solution,W = grams of sample, andLOI = average of duplicate loss on ignitions.9. Precision and Bias9.1 Test ProgramAn interlaboratory study was conductedin which the weight % palladium (volatile free basis) wasmeasured in one separate test material in eigh
38、t separatelaboratories. Practice E 691, modified for non-uniform datasets, was followed for the data reduction. Analysis details arein the research report.9.2 PrecisionPairs of test results obtained by a proceduresimilar to that described in the study are expected to differ inabsolute value by less
39、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 usage are given in Terminology E 456 andPractice E 177, respectively.Test Result(Consensus Mean)weight %95 % Repeatabil
40、ityInterval(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 known bias.10. Keywords10.1 atomic absorption; molecular sieve; molecular sievecatalyst; palladiumASTM International
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