Updates on New Eichrom Chromatographic Updates on New Eichrom Chromatographic Materials For Radium Separation Including Materials For Radium Separation Including

MnOMnO22

DGA DGA

Sr2Sr2

Natasha Dimova, Bill Burnett - Florida State University

E.Philip HorwitzPG Research Foundation

AcknowledgmentsAcknowledgments

FSU Graduate StudentsFSU Graduate StudentsHenrieta Dulaiova

Ricky Peterson

PG Research FoundationPG Research Foundation

RAD-7-MnORAD-7-MnO22-Resin-Resin automated automated systemsystem for for

measurements of measurements of 224224Ra and Ra and 226226Ra in Ra in water sampleswater samples

MnOMnO22-Resin-Resin Simple sample

preparation High capacity-Kd=2.4x104

RAD-7 counting RAD-7 counting systemsystem

Alpha detector-spectrum of alpha emitters 218Po, 214Po, 216Po

Decay chains of uranium and Decay chains of uranium and thorium seriesthorium series

Bi–21419.7 min

Pb–21210.6 hrs

Pb–21426.8 min

Pb–21022.3 yrs

U-238U-238 Th-232Th-232Th–2281.9 yrs

Rn–2223.8 days

Ra–2261600 yrs

Po–2183.05 min

Ra–2285.75 yrs

Ac–2286.13 hrs

Ra–2243.66 days

Rn–22055.6 sec

Po–2160.15 sec

Po-2140.16 msec

MnOMnO22-Resin: pH dependence-Resin: pH dependence

The separation of Ra2+ is due to the adsorption of the bi-valent ions on partly negative charge surface of the MnO2

Resin

-

-

-

-

-

-

-

-

Ra 2+

Ra 2+

Ra 2+

Ra 2+

Ra 2+

Ra 2+

Measurements of Measurements of 224224Ra and Ra and 226226Ra in Ra in water samples: automated system water samples: automated system

schematicschematic

IN

OUT (pump)

DRYING TUBE

RAD-7

224/226Ra on MnO2-RESIN

x

FILTER

x

TWO-WAY VALVE

1/4˝

1/4˝

1/4˝

3/16˝1/4˝

1/4˝

1/4˝

RAD-7 - MnORAD-7 - MnO22-Resin:-Resin:recommended protocolsrecommended protocols

Ra-226 Ra-226 (T1/2=1600 y)

Flush for 10 min thru cartridge and switch to protocol:

ch.A: use after 1st 15 min ( 218Po = 222Rn).

ch.(A+C): use after 3 hrs (214Po = 222Rn).

use a count time long enough to ensure good counting statistics.

Ra-224 Ra-224 (T1/2=3.6 d)The cartridge must be

continuously flushed: ch.B: use ~15 min cycle with

about 10 recycles.• equilibration in the 224Ra–

220Rn chain (requires ~ 5 min).

• use “DRYSTIK” to control moisture.

count time long enough to ensure good counting statistics.

RAD-7 - MnORAD-7 - MnO22-Resin:-Resin:calibration curvecalibration curve

INGROWTH TIME, HRS

0 50 100 150 200 250 300

AC

TIV

ITY

, CP

M

0

100

200

300

400

500

600

ch (A+C)a=510

ch Aa=250

Y=a(1-EXP(-0.00752X))224/226Ra on

MnO2-RESIN

TWO-WAY

VALVE

Comparison of DGA Resin, Normal Comparison of DGA Resin, Normal and Diphonix: retentionand Diphonix: retention

DiphonixDiphonix DGA Resin, NormalDGA Resin, Normal

Ra-228 via 2-Column ApproachRa-228 via 2-Column Approach

Nour, S et al. / Applied Radiation & Isotopes 61 (2004) 1173-1178

IIDiphonix

sample in 2M HCL

HEDPA – AC

RaRa2+2+

hold >30 hrsAc3+ ingrowth

HEDPA – AcAc3+3+

RaRa2+2+

IDiphonix

alpha source

sample in 2M HCL

LSC oxidation for discarding organic component; beta counting

Comparison of DGA Resin, Normal Comparison of DGA Resin, Normal and Diphonix: elutionand Diphonix: elution

DiphonixDiphonix DGA Resin, NormalDGA Resin, Normal

TN-DGA-extraction chromatographic TN-DGA-extraction chromatographic

resinresin

Extractant:Extractant:

MM (( NN OO33))

33 EE

33

MM == LL nn ,, AA nn

MM33 ++

++ 33 NN OO33

--

++ 33 EE

N,N,N’,N’-tetra-n-alkyl-3-oxopentanediamide (TN-DGA)

OR

N

R

O

N

O

R

R

CUMULATIVE (ML)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 280

200

400

600

800

0

50

100

150

200

250

300

350

AC

TIV

ITY

(C

PM

)

Elution0.5M HCl

Load and Rinse4M HNO3

Ba2+ Ac3+

DGA-ConclusionsDGA-Conclusions

Strong retention as Diphonix for tri-valent ions: Kd~105

ml/g. Easier elution from DGA Resin, Normal

• direct counting of Ac-228 on beta counter or LSC.• no need of organic (HEDPA) oxidizing step.• eluent dilute acid (0.5M HCl).

Sr2 Resin, Strontium extraction Sr2 Resin, Strontium extraction chromatographic resinchromatographic resin

Extractant:Extractant:

O

O

O

O

O

O

4,4”(5’)-di-t-butylcyclohexano-18-crown-6

AE 2+ + NO3- + Cr AE (Cr) (NO)3

0

5

10

15

20

25

0 5 10 15 20 25 30CUMULATIVE (ML)

% O

F IN

ITIA

L A

CT

IVIT

Y

Load in 5 ml 1M HNO3

Rinse in 10 ml 1M HNO3

Elution in 11 ml 0.01M HNO3

Ra2+

Ba2+

Summary

RAD-7-MnO2-Resin automated system is a powerful tool for determination of 224Ra and 226Ra in natural waters without chemical separation.

DGA-extraction chromatographic resin has the same high Kd for Actinium as Diphonix with the benefits of easier elution with 0.5M HCl.

Sr2 Strontium extraction chromatographic resin can be successfully used for Ba/Ra separation.