Analysis of Actinide Elements from Large Samples Henrieta Dulaiova Guebuem Kim Bill Burnett Florida State University and E. Philip Horwitz PG Research Foundation

Need for Large Volumes Achieve very low MDA's for environmental monitoring Specialized scientific studies often require large volumes to obtain necessary sensitivity, e.g., Am/Pu in seawater, global fallout in recent soils

Actinide Retention on Diphonix Resin Diphonix Resin high retention of actinides, Ln Low retention common ions Tolerate to HF

Elution: HEDPA Acid Dependency Curves Indicates that actinides should elute easily at concentrations ~0.5M

Protocol for 10  50-g Samples Dissolution/ Leaching Diphonix HEDPA oxidation Resins: TRU TEVA UTEVA Tracers, Fe scavenge 0.1M HCl-0.3M HF, AA  ~1 M HCl-0.5M HF, AA "Matrix" 0.5M HEDPA H 3 PO 4 + actinides, Ln’s { one or more Separation Am, Pu, etc. alpha spectrometry ICP-MS “Fenton’s Reagent” H 2 O 2 + Fe 2+  OH + OH - +Fe 3+ Diphonix bed volume 10  13 mL

Elution of Am

Fenton’s Reagent Oxidation finished Treatment: 40 mL 0.5M HEDPA + 1 mL HNO mL H 2 O g Fe(NH 4 ) 2 (SO 4 ) 2  6H 2 O Temperature ~90 o C H 2 O 2 + Fe 2+  OH + OH - +Fe 3+

Actinide Separations (10-g Samples) TRU  Resin M HNO 3 2.5M HNO 3 /0.1M NaNO 2 2.5M HNO 3 9M HCl 4M HCl 4M HCl/TiCl M HCl 2.5M HNO 3 2.5M HNO 3 /0.1M NaNO 2 2.5M HNO 3 9M HCl 1M HCl 0.1M Ammonium Bioxalate Discard Am Pu Discard Th U Sample (3M HNO 3, 0.7M Al(NO 3 ) 3, FS, AA) Final clean-ups: Am/Ln on TEVA; U on UTEVA TRU  Resin tolerates high PO 4

TEVA  Resin Ln Removal TEVA  Resin Discard (Ln) 4M NH 4 SCN/ 0.1M formic acid 1.5M NH 4 SCN/ 0.1M formic acid 2M HCl Am 2* Am fraction from TRU  Resin HNO 3 + H 2 O 2 oxidation 3 drops of 10 % H 2 SO 4 Conc formic acid, 1 drop dissolved in 10mL 4M NH4SCN/0.1M formic acid

10-g Samples: Yields Samples (n=7): 3 EML soils 2 IAEA sediments 2 Fe-rich soils 7 samples run through entire procedure and analyzed for Am, Pu, U, and Th. 10-gram samples were leached with HNO 3 /HCl.

10-g Samples: Results Table 1: EML and IAEA intercomparison values.

Anal. Chem. Paper

TRU  Resin mL 2.5M HNO 3 5 mL 9M HCl 30 mL 4M HCl 30 mL 4M HCl/1mLTiCl M HCl 2.5M HNO 3 2.5M HO 3 /0.1M NaNO 2 2.5M HNO 3 9M HCl 1M HCl 0.1M Ammonium Bioxalate Discard Am Pu Discard Th U Sample (2.3 M HNO 3, 1M Al(NO 3 ) 3, 0.06 M NaNO 2 ) Final clean-up: Am/Ln on TEVA Not performed Only 3 steps for Am, Pu Actinide Separations – 50 g

Protocol for 50-g Samples Step10-gram*50-gram Leaching70 mL each: 6M HCl/8M HNO 3 4 hrs., 90 o C 150 mL each: 6M HCl/8M HNO 3 4 hrs., 90 o C Load Sol’n Add HF (0.5M), AA, adjust pH=1 ppt Fe(OH) 3 HCl, HF, AA, H 2 O to ~500 mL 1M HCl – 0.5M HF *Kim, Burnett, & Horwitz ( 2000)

Conditions - Diphonix Step10-gram50-gram Diphonix Column 1.2-cm diameter 10 mL resin same 13 mL resin Elution0.5M HEDPA 35 mL same 40 mL Oxid HEDPA* Fenton’s Reagent HNO 3 /H 2 O 2 /Fe 2+ same *Oxidation of HEDPA is done in a glass beaker on a hot plate – the reaction is complete in approx. 40 minutes

Conditions – Final Step10-gram50-gram TRU Column 0.6-cm dia, 5 mL ~15 mL HNO 3 - Al(NO 3 ) 3 -FS-AA 0.6-cm dia, 6 mL ~25 mL HNO 3 - Al(NO 3 ) 3 -NaNO 2 TEVA* (Am) Thiocyanate separation same Source Prep CeF 3 microprecipitation *Am fraction purified of lanthanides on TEVA column to prevent thick source; Pu is processed directly after TRU CeF 3 - more HF for Pu

Spike Tests (50-g Soil) Am-241 and Pu-239 spiked samples. Matrix = HNO 3 /HCl leach of 50-g soil and sediment samples.

Before loading… After ~20 minutesReaction with TRU Observations: 50-gram Samples

Observations: 50-g Samples Solutions highly colored after HEDPA oxidation What was happening on TRU Resin column? Pu co-precipitate with CeF 3 – needs more HF

EML 0009 (Soil) 50-g sample, leached with 6M HCl/8M HNO 3 Run through entire procedure… AnalyteYield % FSU mBq/g EML mBq/g Am ±0.18.3±0.7 Cm ±3~100 Pu-239/ * 16.5± ±0.3 Pu * 18.7± ±0.2 *An additional 29% in 2 nd ppt; so total recovery through columns ~90%

± * Pu ± * Pu-239/ ±0.0194Am-241 IAEA mBq/g# FSU mBq/g Yield % Analyte * An additional 10% in 2 nd ppt; so total recovery through columns ~95% # recommended value/range IAEA-326 (Soil) 50-g sample, leached with 6M HCl/8M HNO 3 Run through entire procedure…

Pu-CeF 3 Co-Precipitation

Table 2: EML and IAEA intercomparison values. 50-g Samples: Results

Comparison of Methods I g10-15 g Fe(OH) 3 co-precipitation EvaporationMatrix reduction Leaching Fusion Soil Prep. FSUWSRCStep Sample size *Maxwell and Nichols (2000) *

Method Comparison II DIPHONIX 13 mL DIPHONIX 2.8 mL TRU TEVA/UTEVA Am, Pu, U, Th TEVA/UTEVA/ TRU/TEVA Am, Pu, U Chemical separation Elution with HEDPA -Fenton`s Reagent Microwave Destruction* FSUWSRCStep * Microwave destruction in closed vessel MW apparatus Oxidation of HEDPA on a hot plate Resin amount Matrix elimination

Summary Diphonix/HEPDA/oxidation process eliminates matrix TRU load with NaNO 2 works best Am/Pu separations work well via TRU  Resin Plutonium CeF 3 co-precipitation requires HF in proportion to am’t HCl