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

Collection/Processing “Mn- fiber” concentrates radium: count 223/224 Ra via delayed coincidence; 226/228 Ra via gamma spect (Dulaiova, 2002)

Ra-223 Distribution Offshore Submarine spring Mixing coefficient calculated from slope of 223 Ra gradient (Moore, 2000)

Scale for Laboratory Use “MnO 2 Resin” Developed by PGRF mesh Preconcentration approach in batch, column, or pump (filtration) modes High adsorption of Ra, trivalent and tetravalent actinides (Ac, Am, Pu, Th)

MnO 2 Resin Experiments  Uptake studies: 133 Ba and Ra; batch and column modes; kinetics; optimum conditions  Evaluate difference in chemical behavior, if any, between Ba and Ra  Evaluate use of MnO 2 Resin cartridge with pump for processing

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

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

Distribution Coefficient A o = initial activity solution A f = final activity solution V = volume solution W = weight of resin

Counting Solution & Resin pH = 3 Variable mass ratios Variable reaction times

Same Experiment, pH =7 pH = 7 Variable mass ratios Variable reaction times

Kinetics, pH  3 pH = 3 Resin = 25 mg Solution = 10 mL

Kinetics, pH = 7 pH = 7 Resin = 25 mg Solution = 10 mL

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

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

Column Experiments

Column Results pH = 7 Resin = 1 g Solution = 1 liter DDW Flow rate  0.65 mL/cm 2.min (gravity flow  1 mL/min)

Pump Tests Peristaltic pump; cartridge loaded with 1 g MnO 2 Resin; single pass

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

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

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

Summary/Future Work MnO 2 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.