Presentation on theme: "Ra in Water using MnO2 Resin: New Developments"— Presentation transcript:
1 Ra in Water using MnO2 Resin: New Developments Sherrod L. Maxwell, IIIWestinghouse Savannah River Company
2 Need for Improved Method for Ra-226, 228 in Groundwater Samples Cation Resin experienceslow flow-1 to 2 days load timepotential calcium interference1 pCi/L MDA requiredneed large sample aliquot (1.5L) for Ra-228 via Ac-228 (gas proportional counting)Test MnO2 Resin developed by PGRF (Horwitz et al) and W. Burnett et al (FSU)
3 Ra-226 and Ra-228 in Water MnO2 Resin from Eichrom 1.25 g MnO2 Resin 1.5 liter samples + Ba-133 tracerpH adjustment to 6-7Flow rate ~20 mL/minVacuum box loading with inner liner~ 1.5 hour loadingspeed & ability to deal with slow samples
4 Ra-226 and Ra-228 in Water Initial testing Strip MnO2 with 20 mL 2M HCL-1% H2O2evaporated and redissolved in 0.075M HCLHold >30 hrs for Ac-228 ingrowthLn-Resin tests10 mL 0.075M HCL load + 5 mL 0.075M beaker rinse10 mL 0.090M HCl Rinse15 mL 0.35M HNO3 stripHad some inconsistencies that seemed related to Mn in load solutionInstead, strip MnO2 with 15 mL 4M HCL-1.5% H2O2 and use…….
5 Ac-228 on DGA Resin TRU (1 mL) + DGA-Normal (2mL) stacked TRU (U,Th removal) and DGA (Ac-228 retention)No impact from Mn on Ac-228 recoveryloaded 15 mL strip solution from MnO2 resin on TRU-DGAcollect load + 5 mL 4M HCL rinse for Ra-22610 mL 4M HCL rinse-discardDiscard TRU ResinStrip Ac-228 from DGA with 10 mL 0.5M HCl100 uL Ce and 1 mL con. HFConsistent high recoveries of Ac-228
8 Ra-226 and Ra-228 in WaterEvaporate load + rinse solutions from TRU-DGARedissolve in 0.075M HClPrecipitate Ra-226 (Ra-224) using Ba sulfate100 uL of 0.70 mg/mL Ba + 3 mL 40% sodium sulfate + 4 drops 1:1 acetic acid/place on ice0.1 mL seeding suspensionCount Ra-226 (Ra-224) by alpha spectrometryCount filter by gamma for Ba-133 tracer recovery
19 Summary Ra-226 and Ra 228 using MnO2 resin Vacuum Box method Benefits Ra-226 using barium sulfate micro-precipitationTRU/DGA Resin -Ra-228 via Ac-228Speed and selectivityVacuum Box methodRapid flow rates1.5 L loaded and stripped < 2 hoursBenefitsFast, easy separation (<1 hr loading for 500 mL groundwater sample)ConsistentIncreased productivity
20 Acknowlegments Eichrom-Larry Jassin and Anil Thakkar W. Burnett et al, MnO2 ResinPGRF- E.P. Horwitz et alDGA and MnO2Joyce Ray, SRS, lab technician
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