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MnO 2 Resin: Concentration of Radium Isotopes

MnO 2 Resin: Concentration of Radium Isotopes. Deok-Soo Moon Bill Burnett Department of Oceanography Florida State University Tallahassee, Florida. Applications in Oceanography. Mixing rates between near-shore and offshore waters Assessment of submarine groundwater discharge.

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MnO 2 Resin: Concentration of Radium Isotopes

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  1. MnO2 Resin: Concentration of Radium Isotopes Deok-Soo Moon Bill Burnett Department of Oceanography Florida State University Tallahassee, Florida

  2. Applications in Oceanography • Mixing rates between near-shore and offshore waters • Assessment of submarine groundwater discharge

  3. Scale for Laboratory Use • “MnO2 Resin” Developed by PGRF • 80-160 mesh • Preconcentration approach in batch, column, or pump (filtration) modes • High adsorption of Ra, trivalent and tetravalent actinides (Ac, Am, Pu, Th)

  4. MnO2 Resin Experiments • Uptake studies: 133Ba and Ra; batch and column modes; kinetics; optimum conditions • Evaluate difference in chemical behavior, if any, between Ba and Ra • Evaluate use of MnO2 Resin cartridge with pump for processing

  5. Tracers, Analytical Approach • Ba-133 (commercial, nominal activity) • Ra-228 (separated from Th-232 solution) • Ba-133 via g-spect (NaI) and LSC • Ra-228 via Ac-228 separation (Diphonix), HEDPA elution, LSC counting

  6. Batch Experiments • Ba-133 spike, adjust pH, react Mn Resin with measured vol, vary time, resin, pH • Filter using syringe • Measure resin with NaI detector • Measure fluid with LSC • Perform experiments with both deionized water and seawater

  7. Distribution Coefficient Ao = initial activity solution Af = final activity solution V = volume solution W = weight of resin

  8. Kinetics, pH @ 3 • pH = 3 • Resin = 25 mg • Solution = 10 mL

  9. Kinetics, pH = 7 • pH = 7 • Resin = 25 mg • Solution = 10 mL Floridan Aquifer groundwater ~40-200 mg/L (0.04-0.2 o/oo)

  10. Optimize Amount of Resin • pH = 3 or 7 • Resin = variable • Solution = 10 mL DDW • Reaction time = 90 min

  11. pH Variation • pH = variable • Resin = 25 mg • Solution = 10 mL • Reaction time = 90 min

  12. Column Experiments

  13. Column Results • pH = 7 • Resin = 1 g • Solution = 1 liter DDW • Flow rate ~0.65 mL/cm2.min (gravity flow ~1 mL/min)

  14. Pump Tests Peristaltic pump; cartridge loaded with 1 g MnO2 Resin; single pass

  15. Ba Recovery vs Flow Rate • pH = 7 • Resin = 1g • Solution = 1L DDW or SW • Variable flow 96.2±2.7%

  16. Ra Recovery vs Flow Rate • pH = 7 • Resin = 1g • Solution = 1L DDW or SW • Variable flow 95.2±5.1%

  17. Ba/Ra Recovery Ratio • pH = 7 • Resin = 1g • Solution = 1L DDW or SW • Variable flow 1.01±0.05

  18. Summary/Future Work • MnO2 Resin adsorbs Ra and Ba very well • Little difference in uptake between Ra and Ba except in sw • Investigate intermediate salinities (typical groundwaters, etc.) • Mate to RAD-7 radon analyzer for Ra-224 • Study adsorption of Am(III), Th(IV), etc.

  19. RAD-7 For Ra-224 Analysis MnO2 Resin can be put in line with a RAD-7 Rn analyzer to quantify Ra-224 (and Ra-226)

  20. Ra Isotopes via RAD-7 Resin Kim et al., 2001, ES&T, 35, 4680.

  21. MnO2 Resin MnO2 Resin MnO2 Resin Drinking Water monitoring Water Pipe

  22. 224 Ra RAD7 Instant. Beta count. MnO2 Resin 226 Ra 228 Ra Several days RAD7 30 Hours Elution-LSC MnO2 Resin MnO2 Resin Drinking Water monitoring

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