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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
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AcknowledgmentsAcknowledgments
FSU Graduate StudentsFSU Graduate StudentsHenrieta Dulaiova
Ricky Peterson
PG Research FoundationPG Research Foundation
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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
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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
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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+
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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˝
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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.
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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
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Comparison of DGA Resin, Normal Comparison of DGA Resin, Normal and Diphonix: retentionand Diphonix: retention
DiphonixDiphonix DGA Resin, NormalDGA Resin, Normal
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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
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Comparison of DGA Resin, Normal Comparison of DGA Resin, Normal and Diphonix: elutionand Diphonix: elution
DiphonixDiphonix DGA Resin, NormalDGA Resin, Normal
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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+
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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).
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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+
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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.