A n1ajor purpose of the T echni-~ ....

c::1i Information C~nte~ is .. to provide tr1e broa est dis~emination possi-ble of information contained in DOE~s· Ref;earch and· Development ~1eports · to business, industry, the academic community, ·and· ·federal, state arid loca_I g vernmentsa_

Althou h a small portion of this report is not reproducible,. it is being rnade. availa~le· to expedite the availabHity of information on _the research discussed herein.

'·

WJCI.E!!..R SCIENCE SERIES Radirx:heaistry of the Element•

""-·

HAS-HS--3063

· DB86 007600 by

Richard A. Roberts Kallinckrodt.Kedical Products R 6s D

· 675 McDonnell Boulevard St. Lou.is, MO 631~

Gregory R. C21oppin Department of Chenis cry Florida State University

Tall.iaassee, Florida

and

John F; Wild· Nuclear Chemistry Division .

Lavrence Livermore Rational Laboratory Liv.ermore, California

Prepared. for Committee on Nuclear and Radiochemistry . Board on Chemical-Sciences and Technology

Colllla!iss.ion on Physical Sciences, Hat:beaatics, and ResourcPs National Acadaay of Sciences--Rational Research Council

February l916

Published by

TEaDIICAL IIFCtaKATIOR C&ti!D. OFFICE OF.SCIDITIFIC AllD TEalRICAL IIQOlllATIOll

trlUTD> STATES D!PARDlilhi OF UllD81'

Forward

The Committee on Nuclear· a~d Radiochemlstry is one cf a nuabar of coamittee• vorking under cbe Board oa·cbeaical Sciences and Technology of the Coeaission on Physical Sciences, Mathematics, and Re~ources of Che Kat!on&l.Acadeay cf Sciences·--Kational Research Council. Ics member• are drawn frou academic, in~uscrial. and government laboratorie• and represent the areas of nuclear chemistry •. radiochemiscry~ end nuclear medicine.

The Committee bas concerned it••lf with those •r••• of nuclear science vhich involve the chemiat, such as the collection mnd distribution of radiochemical procodurea. specialized tcch~iquea and instrumentation, the p1ace of nuclear Rnd radiochemistry in collage and university program•. the training of nuclear and radiocheni•C•, radiochemistry in environmental science, and radionuclide• in nucl~ar aedl~ine. A major intereac of the Committee is the. publicaticn of the Nucle&r Science Series of aonographs on Radiochemistry and on Radiochemical Techniques. In 1982 a third series on Nuclear Medicine ~as initiated.

The Committee has endeavored to preserit aonograpbs that vill be of maxieua use to the working •cicntist. Each monograph presents pertinent information required for radiocheaical •ork with an ind~vidual element or tt!.th a specia"lized ·technique or vith the use of radionuclides in nuclear medicine.

Experts on the various subj~cca h&•e been recruited to write che monographs. The U.S. Departnent of En•rgy spon•or• the printing of the series.

The present aonograpb is a coaprebensi?e revision and update of .three previously published monographs in tbe series oft the Radiochesistry ·of· the Elenents. It is published as part of our continuing effort co ·update, revise. and ezpand tbe previously pu~lished §onographa to keep chea current and relevant.

Edvard S. Macias, Qaairman Conaittee on Nuclear· and Radioche-istry

iii

Pref ace

'.r'his monograph presents s~ procedures used in the radiochemical. isolation, purification and.(or analysis of uranium·,

neptunium, and plutonium. The original r.ao~O

Cpgt,1nt;

[gryz rd ................................. • ........................ iii

f;-e fpce . · ............... · ..................... ~ · ..... · ...... ~ ...... iv

I . Su;p.aty of Previous lt-~~ aniup Procedures . . . . . . . . . . . . . . . . . . . . . . . . . l

II. Su.m;;ary of Previous NtptuJ!iym Prosedyres ..................... ~.2

!iI. Supillg;y of Pr•vioµs Plutonium ProcecJurcs ....................... 4

IV. Nev Uraniua Procedures ......... · ................................ 6

Introduction .................................................... 6

Discussion of Procedures. . . . . . . . . . . . ........................... 6

Procedure•:

1. Semi-Quantitative Df:terminatio·n of Uranium ( aSpectroscopy) .........................•................ 14

2. Concentration of UraniUll by _Coprecipitation vi th Iron-Potassium_ Fe_rrocyanophospheinates ................ 16

3. · Extraction of Uraniuli vith TOA and Spectro-photometric Determination vi.th Arsenazo III ............... 17

4. Determination of Uranium (and :Plutonium) Isotopes in Soil Saaples by a-Spectroscopy ......•......•.. 19

5. Anicin Exchange Separation of U in Kalonic and Ascorbic Acid Kedia ..............•.................... 21

. .

6. Separation of Oraniua from Heavy Hecals by Chromatography Using an Arsonic Acid llesin ....•.. ~ ........ 23

7 airaaatograpbic Separatfon and a-Spectrometric Deteraination of Uranium. . . . . . . . . . . . . . . . . . . . . . . .......... 24

8. Determination of Uranium in Natural Vaters Afte~ Anion-Exchange Separation ........................... 26

9. Urani:ma Analysis by Liquid Scintillation Counting ......... 28

·10. DeteminatiOG of Trace Uranl.um in 'liologlcal llatarlals by Neutron Activation Analyais and Soi'99nt lxtractioa ......•.••....•...........••... ; ..... ~ .. 31

11. Detandnation ~f Trace Uranlua by lnatr1m111ntal ReutTon ActivatiOI'! ~lysis ....•....•....•......•.•....... 33

V. New Nepcuniwa Procedyr11 ..... · ...... _ ........................... 34

lne:gooduc t:ion •••.•.•.•.•.•. , , ...•.......• · ......•................. 34 Procedures:

. . 1. Chromatographic Separation of Nepcunium Using

Quaternary Ammonium Nitrate Extractant ..............•..... 35

2 .· A Spectrophotometric llethod for che Determination of Neptunium in Proces.s Solutions ......................... 36

VI. Nev Plutoniug Proceciures ....................................... 38

Introduction ........................... · ............. · ........... '! 8 -...._

...........

Discussion. of t:he Procedures ....... ; ........ :· .................. 38

Procedures:

1. Liquid-Liquid Extraction Separation and Determination of Plutonium ................................ l10

2. Determination of Plutonium in Sediments by Solvent Extraction ..•............ w •••••••••••••••••••••••• 42

3. Radiochemical Determination of Plutoni\JEI in Marine Samples by Extraction .Chro:.atography .· ............. ·.44

4. The Determination of Plutonium in EnVircmmental Samples by Extraction vi th Tridodecylamine· ................. 46

5. Solvent Extraction Method for Determination o! Plutonium in Soft: Tissue ............................... 48

6. Determination of-Plutonium in Tissue by Aliquat-336 Extraction.· ................................... 50

7. Detemination· of Trace Amen.mt• of Plutonium in Urine .......................•.•........................ 52

8. Extractive Phot011etric Determination of Plutonium(IV) vich Altquac-336 and Xylenol Orange ......... 54

'· Sinultaneou.m Deterainat:iona.of Plutonium Alpha- and Beta-Activity in Liquid Effiwmts and Enviro~ntal ~l•• ........ · ... ~ ......•...............•.•.............. 55

VII. QJd.:Mcien Sq,q Pro£••n1 .... ~ ..................... ·. ~ ......... 57

Introduction .................................. , ................ 5 7

vi

Robert11/Cboppin/Vild page 1

I· · Sumary of 'Previous Uranium Pr~durea · J. E .. Gindler

NAS-NS-3050 (1962)

1.. Determ:Lnation of Uranium -237

2. Purification of Uranium -240

3.. Purification of Irradiated Uranium'-236

4o Urani~~ and Plutonium Analysis

So Spectroph.otometric Extraction Methoos"$pecific for Uranium ··-.

6.. Determination of Uranium in Ur~nium Concentrates

7.. Carr;_er Free Determination of Uranillili -237

8. Radioassay of Uranium and Plutoniwra in Vegetation, Soil~ and Uater

9. Separation of Uraniwn by Sclvent Extracti?n with TOPO

10.. Radiochemical Cetermination of Uranium -237

11. Separation of Uranium ana Bismuth

12. Isolation and Measurement of Uranium at the Microgram Level

13. The Determination of Uranium by Solvent Extraction

14. Uranium Radiochemical Procedure ••'Sed at the U.S. Rac";iation Laboratory at Livermore

15.. Use of Ion Exchange Resins for the Determination of Uranium in Ores and Solutions

16. The Use of a Compound Columr1 of Alumina and Cellulose for the Determination of Uranium in Minerals and Ore~ Containing Arsenic and Moly~denwr:

17. Determination of Uranium -235 in Mixtures of Naturally Occurring Ur~nium Isotopes by Radioactivation

.1.b. Determination of Microgram and Submicr09cam Quantities of Uranium by Neutron Activation An.alysis

Roberta/Choppla/V1ld ,... 2

II. Sumarz of Pravloua Heptunl~ .-roc•durea

G. A. Burney and R. M. Harbour RAS-BS-3060 (1974)

1. Separatio~ of Np by TTA Extraction

2. Separation of Np by 'l"l'A Extraction

3. Determination of 23 'Np in Samples Containing u. Pu, and

4.

s. 6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

Fission Products , '•,

Determination of Hp

Determination of Small Amounts of Np in Pu Metal

Determination of Np in Samples Containing Fission Products, u, and Other Actinides

;·.-etermination of Np in Samples of u and Fission Products

:~xtraction Chromatographic Separation of 23.'Np from Fission ~nd Activa~ion Products in the Determination of Micro- and 3ub-Microgr~m Quant.i~i.!!G of U ·

Separation ·of u, Np, Pu, and Am by Reversed Phase Partition Chromatography

An Analytical Method [or 237Np Using Anion Exchange

3eparation of u, Hp, and Pu Using Anion Exchange Separation of Zr, Mp,- and Rb Using Anion Exchange

Separation of Np and Pu by Anion Ex.change

Separation of Rp and Pu by Cation Exchange

Separation and Radioc~~•ical Determination·of U and Tranauraniua Elements Using Barium Sulfate

The LOw-Level. Radioch .. ical Deterainatlon• of Z3 7Np in Environmental Samples

Radiochemical Procedure for the Separation of Trace Amounts ~f Z17Hp from Reactor Effluent Water

Determination of llp in Urine

Roberte/Choppin/Vild pap 3

suma9 of Previous 5eptunba Proced1ft'ea, continued

19. Determination of 237Np by Gamma Ray Spectrometry

20 •. _Spectrophotometric Determination of Np

21. Microvolume_tric Complex0111etric Method ·for Np with EDTA ·

2.'2. Photometric Determination of Np as the Peroxide Complex

23. Separation of Np for Spectrographic Analysis of Impurities ·.

24. Photometric Determination of Np as th~··~xylenol Orange Complex

25. Analysis for Np bY Controlled Potential Coulometry

Roberta!Choppin/Wild page 4

III. S~rv nf PrevioUA Plutnnt\Jllt Procerlure~ G. H. Coleman

NAS-NS-3058 ( 196_5)

1. Determination of Pu in Solutions Containing Large Amounts of Fe and Cr·

2. Separation and Determination of Pu by TTA Extraction

3. Separation and.Determination of Pu in a-Fission Procluct Mixt~res ,,

4., Plutonium

5. Plutonium

6. Separation of Plutonium from Uranium and Fission Prod·ucts in Irradiated Reactor Targets

7. Determination of Pu

B. uranium and Plutonium Analysis

9a. Separation·of .Plutonium fran Irradiated Uranium

9b. Separation of Plutonium from Uranium Metal

10. Purification of Plutonium fran Uranium and Fission Products

11. Uranium and Plutonium from Environmental Samples of Soil, Vegetation, and Water

12. Pluto~ium from Environmental Water Samples

13. Plutonium from Environmental ~ater Samples

14. Separation of Plutonium in Uranium-Plutonium Fission Element Alloys by TBP Extraction from Chloride Solutions

15. Separation of.Pu before Spectrographic Analysis of Impurities Anion Exchange· Method .

16~ Separation of Piutonium Before Spectrograpbic Anlaysis of Im.purities. Extraction Chromat09raphy Method Using TBP

17. Separation of ·Hp and Pu by Anion Exchange

18. Separation of Hp and Pu by Cation Exchange Chromatography

19. DetenninatiOI' of Plutonium in ~rine '·

-~

Roberts/Choppin/V1ld page 5

SuZ1:1aEy of Previous Plutonium Procedures, continued

20. Determil'iation of· Pu 239 in Urine (S~all ·Area Electrodeposit_ion Procedure)

21. Determination of Plutonium in ·urine

22. Determination of. Americium in Urine i'rr-.. ~he Presence of Plutonium

· 23. i:>eter.ninatiori of Plutonium in· Urine by Anion Exchange

24. Determination of Plutionium in Urine .by Cocrystallization _with Potassium Rhopizenate

25. Determination of Plutonium in Urine and Bone Ash by ·Extraction wi-th .Primary Ami wtes

IV. Nev llr11ntU111 'Pri'.'cedures

INTRODUCTION

Roberts/Choppin/W1ld page 6

Since the publication of the original monograph on the radio-chemistry of uranium in 1962, much attention has ~en given to aethods of separation, isolation, and measurement of small amounts of uranium in various types of samples. Such samples involve geological, biological, and environmental matrices, fx-equently of high ccaplexi'ty and lcw uranium content. The procedures foi:-_ such samples collected in this monograph are meant not to supplant,·· but rather to supple-ment those in the original monograph by allowing applicability of the procedures to a wider variety of sample types.

These new procedures were chosen to provide description of a wide variety ·of techniques rather·than to fccus on any p~icular method, such a.s neutron activation analysis or solvent extraction. Some of the procedures emphasize the separation o! uranium from other elements,.while for others, the main focus is the method of measurement.

A complete procedure generally can be divided into three operations: l) ·sample preparation, 2) separation of the element(&) of interest, and 3) analytical measurement. In many cases a specific operation from one procedure can be used in conjunction with other operations from. anothe- prqcedure. This should allow a broad spectrum. of sample types. For each of the ~ol1ected procedures, sample types to which the procedure may be applied are given. A more complete discussion of each procedure and addi~ional information regarding applications can be obtained from the original reference. Iq_some cases, additional references are listed, as they ftontain similar, -related procedures and might be of interest in the case of some particular sample.

DISCUSSION OF THE PROCEDURES .

The first two procedures involve precipitation.of uranium. from large quantities· of water. In the first procedure, NaOB is used to precipitate uranium from seawater. The efficiency of recovery of.uranium and other heavy radionuclides from 750 grams of seawater by this procedure is shown in Figure 1. The "dependency of the recovery efficiency on the vo1ume of NaOH added is evident, with ma.xiaum recovery occurring after addition to tha 750 gram sample of at least 8 ml of l.O K RaOH, which cori-.esponds to ~ final NaOH concentration of approximate1y 0.01 !· For different volumes of samples, the amount of base to be added should be modified so as to obtain a comparable NaOR concentration. Figure 2 is an al.pha·spectrua of a uranium sample obtained froa the use of thie method. ·

>-a: LI.I

~ u ..... a: 'II!

100

50

0

.......

4~--6 ~.;..-e.........-- I=

. ~

~I/~, ./

238., 254

0 .u

-~ a245Am &

255Pu

I 5 10

ml oi 1.0 M NaOH ADDED

labezta/CbapplD/llild , .... 7

FIGURE 1. Recovery of uranima (lmd o~beT added nuclides) from 7 50 ml of sea va~er vi tb ~ • . ..,.. volumes ·of 1. 0 K NaOH :sdded. (See Proc.•- .. :. ~ ~ for reference J .-

~ ! I .. I

I ~

~ l z i ~ j :c r u I a:: t00~ w r CL i

en 1-z ::::> 0 u

' i l ~ .. I I . I . .. ~

Zl& u

I

CHANNEL NUMBER

'·· ......... _ .,_

~o !

FIGURE 2. Alpha activities of natural uranium plated directly onto n counting disc from the dissolved precipicate of 740 grams of Scripps Pier sea water. (Note the absence of other activities in_the 4a0 - 5. 7 MeV energy range). (See ·-Procedure 1 for reference).

Roberts/Chopp1n/Vild page 8

loberts/Choppinl'Uild pap 9

The second procedure involves the coprecipitation of ~ra.nium wi~h iron potassium ferrocyanophosphonatea. ·This procedure ca.:• be. used with larger volumes (several liters> of va:ter and aives

-a slightly better recovery in same cases. ·

Procedures 3 ana ~ involve solvent extraction to praconcen-. tra~e and isolate the uranium. Procedure 3 uses tri-n-octylmaine (TOA> u extractant; details on the ch.aistry of this extractant is described in the original uranium ~noeraph~CHAS-NS-3050>: This procedure mraploys spectrophotOllletr1c &nalys1•,of ·the uran1ua by 'the use of arsenazo III raqent, vhich has coma-· into· vide use since the publication of the first ilLonograph ancf is an excellent reag~nt for the spectrophotometric determination of uranium. It forms a brightly colored complsx vith uranium CVI) and can be used to detect uraniua in the part-per-million ranie (and, in some cases, in even lover concen-crations). Tha original series of ar'ticles on the use of this reagent 1 -:1 should be read for details.

Procedure ~ a1so uses trioctylaaine in the solven~ extraction of uranium from acidic aqueous media. This procedure employs the use cf 211 U tracer to correct for the low (2 - 10\) uz-:niua yield. ·This isotope is convenient to use as a tracer since its alpha decay energies. Ca.nd those of its daughters) are above

. S.8 MeV and therefo~ do not interfe1-e in alpha spectroscopy with· the peaks of the more commonly encountered uranium. .ittotopes. The preparation of the 111U tracer by itTadiation of thorium is also d~scribed in the procedure•. The alpha ·spectrum of the puri-fied iJ•u Cand its daughters) is shown in Fiff:9 3, in which the separation from the alpha spectra of 11 -u, 1 1 U, and 211U is easily seen. Quantitative analysis of samples is obtained by . alpha spectroscopx and an.appropriate yield correction obtai.ne~ from the ZJou. Although the yield is lov, this procedure .is a useful one for ·sail vhose complexity causes the lov yield.

. Procedures 5, 6, 7 and 8 involve ion exchange chromato-graphy. P~ocedure S used Dovex-21K resin in either the malonic or ascorbic acid form for the separation of uranium from other metal ions. This procedure is capable of separating uranium from. a host of other metals, and is therefore useful for purifying uran-ium from highly contaminated samples such as fission products. Uranium forms ·a s-:ronger anionic ccaplex with ~th malonate and ascorba~e than most other metals and is retained on the column while other metals are preferentially eluted with a series of increasingly stronger eluting agen~s. Reported recovery is excellent~ 99\ + 1\. Additionally, the procedure allows purifi-cation of thoriUm., if i~ is present in the saaple.

. Procedure · 6 uses Aaberl.i te XAD-16 resin, converted 1:0 the arsonic acid form, to separate uranium from "na"tural. vat•rs in saaples of up to one liter in volume. Uranium recovery is dependent on pH, as shown in Figure "· Recovery and separations frma o'ther meta.1 ions is reported to be very good, vith chrcaiuaCIII) beiq the only interference. W"nen present in equal concentration vith the uranium CO.S ppm), approxima:tely ll\ of t:he···chromiua was eluted with the uranium fraction.

-N . N CICI u') "'": .. 0\ ,.: t»

If)

""'= an C» 'O' ~ ::> 0 -c ::> 0 c N .. ....

..j- .... N e N .=. ::> u • '° "" ""' r.. ... ~ .,

co 1111

C\i~ .. N-.a ,.: d) a:: "V"1: c ll""IN a: 'Iii 4! ;c ... ~ .. ...

N

'"

~J: ~

+o ~ ~ ..

c;i

J6.S j .. ' ..,6.0 .. '

Roberts/Chopp in/Wild page 10

> @

~

>. 0 ... • cl a. .; c

""? t

• -c ~ 0 u

L&J ~

, ::> ~5.S en 0 .... g;

N Q. -!

j -~

100

60 > 0: l&J

60 > 0 f&:l 4C a::

ti- I 20

Robert•/'~oppin/Wild page 11

,..()

-2

// /0 I

/0 6_,a I A,/

.~~

_, 0 2

pH

'··

0 Th+4 d Fe+3

A ua;2

4 5

FIGURE 4. Effect of pH of retention of Th(IV). U(VI), and FE(III) on mi arsonic acid column. (See Procedure 6 for reference).

6

Rober:a/Chopp1.n/V1ld page 12

In P:·oc'3dure 7, an ini 'tial column s·eparat:ion using R.DEHP Cdi.-2-c'thylhexylphosphoric acid) supported on O.l - 0.2 11111 Teflon oeads is used both to isolate the uranium fraction from a sample and ~o separate the inclividu&l UCVI) &nd UCIV) fractions. The sepa.rli:te !ract:ions are purified by passage ""through anion-exchange resin columns prior t:o alpha spectromet-ry. ~e amounts of :"eCIII> in a sample a.re reported to interf~re with the separation. However, reduction to FeCII) wit:h hydrazine hydrochloride eliminates this interference.

Procedure 8 employs a tet:r&hydrofuran-methy1 glycol-HCl cixture wi t:h Dowex-1 anio':l resin to separate ura... : :m from acidified natural waters. Quantitative anal.ysis is performed bv optical spectroscopy with arser..azo III.

An increasingly important analytical tool for alpha emitters is employed in Procedure 9 wherein liquid scintillation alpha counting is used to ~~t:errll.ne uranium in biological samples. Ins'truc'tions are givr~; for. t.~~ .. use of bo'th extractive .::.nd dispersive scintillation cocktails. n.~ c;.

'·

REFERENCES

l. S. B. Savin, T&lanta, !• 673-685 (1961). 2. S. B. Savin, Talantc, _!!, 1-6 (196-).

3. S. B. Savin, T&l&nta, 11, 7-19 (196-). -

... __

JlaMrte/Cboppla/Vlld .... ll

II. J. Hashimoto~ K. Taniguchi, B. Sugiyama, and T. Sotobayuhi, Journal of Radioa..--ialytical Chemistry, !!• 133-1-2 (1979).

s. w. Davies ~d w~· Gray,.Talanta, !!• 1203-1211 Cl9&~>.

Roberts/Choppin/Wild p•ge 14

Semi-Quantitative DeteX'mination of Uranium Ca-Spectroscopy)

Source: v. I... Hodge, M. E. Gurney, Anal~ica.l Chemistry, 117, 1866-68 (1975)0

Sample Type: Sea Water

Procedure~

1. Wei~~ 750 g of sea water into a l liter polyethylene bot-tle (whose t~p has been cut off).

2. Add 8 to lO ml of l.O H NaOH while stirring rapidly with a magnetic stir ~ar.

3. Continue stirring for l hour, then allow 'the milky precipitate to settle overnight.

~- Compact 'the precipitate by centrifuging the liter polyethylene bottle at 2500 rpm for 15 minutes (Note l).

5. Pour off supernatant sea water.

6. Dissolve the precipitat~ with 2 ml of 12 H HCl and ·add 3 drops of 0.01.J\ thymol blue indicator.

I. Pour the solution into a. plating cell.

8. Add l ml of 12 H HCl and 2 ml of deionized water t:o the poly bo'ttle.

9. Wash the walls of the bottle with this solution and transfer to the plating cell.

10. Wash the bottle once a.gain with 1.5 ml of deionized water and transfer to the cell which has a stainless steel ~ounti.ng planchet as the a.node.

ll. Neutral.ize the contents of the plating cell with 1.5 m.l of 15 M NH~OB to a pB of 2-3.

12. Plate the sample at o.ag. amp/CJ1A2 current ~ansity for l hour. Baf'ore s'toppi.ng the electrolysis, add l al. of l.S 1:1 D• OB to 'the cel.l. DisaOl&ble the cell and prepare 'the disc for counting by vaahi.ng with water and acetone, than dryina. Count vith a ai1icon surface barrier detector (the authors reported. waiq a 300-1150 11111 a de'tector aoni 'torad by a pu1se height analyzer; counting ti.lies of roushly 1000 11..inutes) (Ko'te 2).

Roberts/Cboppin/Vild pap 15

flote l: The reported precipitation efficiency for uraniwa is.86 + 2\ using 8 ml of 1.0 H HaOll to effect prici~I'tation. This value can be Wl".td in e&l.cul-a.1:iona for sami-quan'ti'tativa a.nalyaSa·, or a tracer could be added (see the original mvcicle).

Note 2: Pu and Am are coprecipi'ta'ted and c4'pla'ted with the uraniwa. All three elements are ;.den'tified and measured by 'the alpha .anergy spec·~try ..

PROCEDURE 2

Robt.>rts/Chopp!n/~ild page 16

Concentra~ion of Uranium by Coprecipitation with Iron-Potassium Ferrocyanophosphonates

Source: V. P. Kermanov, D. A. Fedoseev, Ra.diokh.i.Jniya, 18, 827-29 (1976).

Sample Type: Aqueous

Procedure:

l. To 5 li-:ers of wa1:er containing uranium,. add the followin~:

7 ~l KIOMPA Cmonoisooctylethylphosphonic aciu) 5 ml tol;.i.ene 1.5 ml kerosene 100 mg pot~ssium f errocyanide 1.3 & ferric ~hloride

2. Mi~: 'thoroughly for 15 minutes.

3. Filter the precipitate.

4. Transfer to a weighing bottle or metallic substrate.

Extraction efficiency: 93 + 14\

lobert&/Chcppln/Wtld .,_ page 17

PROCEDURE 3

Ext:racl:ion of Uranina with TOA and Spec'trophotom•tric Determination with Arsenazo III · ·

Source: H. Onishi, K. Sekina, Ta Lan'ta, !!;1 11_73-78 (1972)

Sample Type: Acidic aqueous

Procedure:

Solutions: Thenoyltrifluoroacetone, 0.5 K - dissolve ~5 1 TTA in '400 ml of xylene.

Tri-n-octylamine - dissolve S 1 TOA in 100 1 of _Xylene. ·

Cresol Red - dissolve 100 ma of Cresol Red in 26 ml of 0.01 K. NaOH ar.d dilute to 250 ml with water ..

Aqueous_ Arsenazo III solution - 0.10\ v/v°'

l. The sa::ple containing 0-5 1.11 of .uranium should be made to a volume of about 20 m.l and .. ! in hydrochloric acid.

2. Transfer the sample to a 100 ml .;eparatory funnel and shake for 10 minutes with 10 ml of the Tl'A solution to remove iron.

3. Allow the layers to separate and drain the aqueous phase containing any UCVI) into a second separatory funnel.

... Wash the organic phase by shaldn1 for 5 minutes witll 3 ml of ~ M HCl and add this aqueous wash phase to the original aqueous phase in the second separatory funnel. .

S. Add 10 ml of TOA solution to l:he second separatory funnel and shake for 2 minutes •.

6. Allow the layers to separate and drain off the aqueous phase.

7. Wash the organic phase by shaking for 2 minutes with 3 ml of ~ M H~l, and discard the aqueous phase.

8. Ba.ck-extract the uranium by .adding 10 mi of 0.3 M HCl to t~~ organic phase and shaking for 2 minu~es.

9. Transfer the aqueous phase to a third separatory funnel and shake the organic phase with 3 ml of 0.3 M HC1 for 1 minute.

lO. Add this aqueous phase to the third s•·~aratory funnel and discard the organic phase.

lloberts/Chopp1n/V1ld pap 18

11. SbAJce the aqueous. phase for l ainute with 5 al of xylene.

12 •. Transfer the aqueoua phaae ·(containinc the ur&niua> to a 25 al voluaatric flaak tbroulh filter paper.

. . 13.· Add l ml of l' ascorbic acid solution. l"dr.op Cresol Red

solution, and adjust ·the pH to O.S-2.0

" '"-.. Roberu/Oloppin/Wild . P•I• 19

PllCCEDURE ~

Deterair.ation·llf UraniWI .

Dissolve the ~l target in a mixture of. HN03 and HCl solution containing as 1 amount of HF.

Evaporate to near ·dryness and convert to 8 H HCl solution.

Purify the uranium fraction by anion exchange.

Procedure for Soil Samples:

1. Dry the _soil sample in sunlight, then crush ~o a fine powder.

2. Dry the powdered s~les in an elec~ric furnace at ll0°C for one day.

3. Pas~ the sample through a 32 mesh sieve and weig~ a Sd g saaple.

&I. Transfer the sample to a l .Liter bealce.r containing 200 ·ml of 8 ~ HN03 , and add a known activitiy of

111U tracer.

5 .. Digest the· sample with ultrasonic agi ta'ti_on for 2 hours, then boil gently for a few hours.

6. Let the sample stand overnight at room temperature, then filter through glass fiber paper.

7. Concentrate the filtrate to about 100 ml under. an infrared ~p.

8.. Add several drops of 30\ H2o2• ~d evaporate to near dryness.

9. Redissolve the residual substance in 200 ml of 8 ~ HN03 anti filter through filter paper (No. SA).

~x~raction Procedure:

·ifoberu /Chopp in/Wild p•ge 20

l. The extracT.ant should be prepared as lOCv/v)\ T~A CTrioctylamine> in xylene and equilibra~ed wi 't·~ an equa_l volume of 8 ~ HHo

3•

No'te: In.the fullowing extraction and washing steps, shaki.~g 'times are 10 minutes.

2. Ex'tract twice with SO ml of the TOA/7ylene &~~ractant and save both organic phase_s • · ·

3. Wash the combined organic phase with 100 ml of 8 -~ HN03 Cto remove ferric ions>. --

4_. Wash the organic phase with 100 ml of 10 M HCl ('to remove 'thorium).

5. Scrub the organic phase (containing ·u and Pu) with SO ml of distilled water and then SO ml. of 0.36 M HCl + 0.01 H HF solution~ _Collec't both aqueous phases in a Tefion bi'alcer.

. .

6. Evaporate the combined aqueous phase under an ~nfrared lamp.

7. Decompose organic. impurities by repeat~ly evaporating with concentrated HN03 ~ontaining HClO~ until no fuming due to HClo~·occurs. · ·

8. Dissolve the residue in 0.5 ml of 1 ~ HN0 3 solution.

9. Electrodeposit the U (and ?u) on a counting planchet us!.ng 10 ml of 0.2 ~ammonium formate as the electrolyte and a curren't densi~y of 0.15 aap/Cllf for 50-60 minutes.

10. Count the sample with a silicon surface barrier detector combined with a pulse-height analyze~ •

. Note: Because of the relatively short half-life of 211 U Ct~ = 20.~ d), a correction for decay should be made. Alternatively, 211 U activity coul~ be calculated from the activities of its daughter 21 Th and granddaughter 222 Ra, which will be in se~ular equilibrium with the pal'ent 1 1 1 U •

Uranium Yield: Reported as approximately· 2-10\ depending on a given soil sample.

· .....

PROCEDURE S

aoberts/Choppin/Wild page 21

Anion Excha.nse Separation of U in Kalonic lUld .Ascorbic Acid Kedia

Source: H. Cha.kravorty a.nd·S. H. Khop.kar, Chromatographia:- .!!!,, 372-76 (1977).

Sample Type: Aqueous solutions, fission products, .. mineral~

Procedure:

Column Preparation:

l. Pack a 1.:. x 18 cm column with Dowex-211< resin CSO··lOO mesh), Cl - form).

2. Convert to the malonate or asc:>rba'te form by passing l!;O ml of 5\ malonic or ascorDic acid buffered at pli ~.S through the column.

3. Wash the column with water.

Sorption:

l. To a sample of appropriate volume (see note in the next step) add 0.2 g of malonic or ascorbic acid-as applicable.

2. Adjust ~hep~ to ~.S with l H NH~OH and l\ malonic or ascorbic acid as app1icable.

Note: The total volume of solution should be about 10 ml..

3. Sorb the solution onto the column (previously described) at a flow rate of l ml/min.

Note: In the following elution steps, a step may be omitted if the indicated elements are not present in the sample.

Separation of Kalonic Acid Media:

l. 'I'lCI>, HgCII>, TeCIII>-z BiCII!), allca1is, and alkal.ine earths are not sorbed onto the c.olumn and are e1utec! in step 3 above.

2. MnCII), CoCII), NiCII), ?dCII), Zn, a.nd Cd are eluted with w~ter.

3. Sb(III), FeCIII), Al, and CrCIII, IV) are eluted wi'th 2 ~ NHaiC'!.

Ii. CuCll), VCIV), and Ho(Vl) are elut:ed with 2 M NaCl.

S. PbCII) and 7.nCIV) are eluted wit:h 1 H ammonium ace'ta'te.

Roberts/Choppin/Wild page 22

6. Ceria earth la.ntha.nides cL."""e eluted with a.OS M HCl.

7. U is finally eluted with l ~ HCl.

B. If.Th is present 11 step 7·is omitted and the Th is eluted with 100 ml of 0.25 M KN0? 11 and U eluted next with 150 ml. of 0.25 M HN0

3• - ""

Separation in Ascorbic Acid Kedia:

l. Alkalis and alkaline earths are not retained on the column and are therefore eluted in the original sample solution.

2. Cr, HnCII), FeCII), CoCII),, NiCII>,, PdCII), Zn, Cd, AlCIII>, SbCIII), and PbCII} are eluted with 200 ml water.

3. ZrCIV) is el.uted with 1 M amrionium acetate.

~. V(!V) is eluted with l ~ NH4Br.

S. Y is eluted with 0.1 M HCl.

6. Ti(IV) is eluted with 0.2 M HCl.

7. U is eluted with 1 H HCl.

e. If Th is present, it can ~e eluted afte~ elution of U with 3 M HCl.

9. If Ko is present, it -can be eluted after the uranium with 1:7 a.milOonia containing 3\ CNH4 > 2so~.

Mote: In all cases C for both ma.lon.ic an~ ascorbic acid media) the volume of elutant is 200 ml, unless otherwise noted.

Yield: Reported yield is 99 ~ 1\.

....

PllO'"'..EDURE &

lobert11/Choppln/V11.d page 23

Separation of Uranium from Heavy Metals by ChrCmatography Using an Arsonic Acid Resin

Source: J. S. Fritz, E. M. Moyers, T&l.anta, 23,590-93. (1976). -Sample Type: Hatural waters

Procedure:

Re•in Preparation:

l. w.uh a quantity of XAD-11 macroporous resin (150-200 aesh) with acetone ·and concentrated HCl.

2. To the resin, add a 60-.. 0 v/v mixture of sulfuric and nitric acids at 0°C. Raise the temperature to 65-70°C for half a clay.to nitrate the resin.

3. Reduce to the amine at 7J-i5°C by adding mossy tin in c~ncentrated hydrochloric acid (reaction allowed to proceed for ha1f a day>.

"· Slurry the product with l !! NaOf! Cto remove tin salts).

5. Cool to 0°C in concentrated HCl.

6. Diazotize by slow addition ot l ~ Na.No,,.

7. Wash the resin with sodium carbonate solution, and convert the resin to the arsenic acid form with sodiua -.rsenite Cin aqueous solution) at i0-75°C.

8. Pa.ck a column C 2. 8 x O. 6 cm) with O. 5 g of the prepared resi.n.

Separation Procedure:

l. Buffer th~ sample solution containing uraniuaCVIl Cup to one liter) to pH 5.0 w:~ orthophosphoric acid and ammonia and make to 0.01 K in EDTA.

2. Pass the solution through the resin column at 7 ml/min.

3. Wash the resin with loo ml of O.Ol M EDTA buffered to pH 5.0 (with phosphoric ~c~d and ammonI'al.

16. Wash with 100. ml of pH 5. O wash. sol.u'tion (no EDTA, no -~aJ.s.).

s. S'trip 'the urani~ f~ the column with 25 ml o: 16 !! Hc10 ... Recovery:. . Uran1~ 1s successfully sep&r&'ted .from other .. tals

by. this· procedure. ChromiumCIII) gives • slight interference (ca. 11\ recovery). Urani'um recovery is reported at 98.3\.

PROCEDURE 7

RcberLa/Chopp1n/V1ld page 24

. . .

Chromatographic Separatio~_and A-Spectrometric Determination of Uranium

So1irce: R. V. Bogdanov, R. A. Kuznet:sov, Rac!iok."s.i:U.ya, !!• 502-it (1975).

Sample Type: Acidic media, uranium content 1-100 J,lg

Procedure:

Column Preparation:

l. Column size is det:enained by sample volume and composition. Linear flow rates up to 10 cm/min are acceptable.

2. Teflon ~ith a grain size of 0.1 - 0.2 mm serves as the carrier. A 1:1 solution of RDEH~ CdiC2-et:bylhexyl) phosphoric acid) in acetone is passed through t:he column, and the solvent: is then removed by purging with air. ·

Initial Separation:

1. Pass the sample solution through t:he column (optimum solution pH is 1-2).

2. Wash the column with 0.01 H HCl. -3. Remove Fe3 + (and .. some other elements> by washing with 'three

column volumes of - ~ HCl at a flow·rat:e of 2 ca/ain •

.... Elute UCVI) wit:h 12 M HCl (six column volumes at·a rat:e ·of 11- cm/min).

S. · Wast- column with water.

6. Oxidize UCIV) to UCVI) with 15\ H2o2 (11--S column volumes).

7~ Wash the colwan with water and elute the UCVI) vith 12 K HCl. . .

Note: Thorium is still on 'the colum.'l a:t t:his point and can be eluted with 6 M H3Po4 or a solution of 0.5 M H2c2o2 + 0. 05 M Hlro3 •.

·Purifica'tion:

·l. Add one drop .of HClO.., .to _e_ach uraniwa fraction and evaporate to dryness. ·

2. In a Teflon cup, treat the residue by adding 2 ml of 8 !! IDf03 and evaporate to dryness.

Robert•/Choppia/Vild pap" 25

3. Repeat the addition of 8 ~ HH03 and evaporate to & voluaa-of 1-2 drops.·

Ii. Cool the cup and add II drops of 8 ~ 81103•

5. Transfer to a 2 x 80 • colwm containing AY-17 anion-exchange z".esin in the nitrate form.

&. Rinse the cup and add the rinse solution.to the colwan~ allowing the combined solutions to pass throuih _the coluan.

7. Wash the column witb six colUllll volumes of 8 ~ HH03 Cto remove nonsorbable·eleaents). 8. Ura.niwa is eluted with 10-columns of l.S ~ RH03•

9. Ad~ one drop of RC1011 to t~e uranium solution and evapora.te to dryness.

10. After evaporation, treat the residue by heating with l al of O. 2 K HCl. -

ll. Evaporate to a volume of 2-3 drops and .cool.

12. Add 6-8 drops of ethanol and ·::ransfer to an electrodeposition cell.

13. Repeat the treatment with 0.2 K HCl and transfer this solution to the cell. A current of 110-~0 l!IA for 3 hours is used for elec~eposition.

l~. After electrolytic deposition is completed, the solution is remuved rapidly and the cathode disc is washed, dried and counted with a. surface barrier detector.

Notes: · .

.! • The method, when carefully executed·, gives a uranium yield. of 96 + 3\. For more precise work, a .z J 1U ~acer can be added-to the original sample.·

2. Substantial amounts of Fe i+ have an adverse effec:s o.n. the separations> so iror. should be reduced to Fe 2 with hydrazine hydrochloride in samples of high ircn content.

3. The cell is A Teflon cylinder of 16 mm diameter and a height of 35 mm. The cathode is a counting planchet of Ni or Cu; the _platinum anode is positioned 15 aa above this cathode.

Rob•rts/Choppin/Wlld page 26 ·

PROCEDURE 8

Oete:-m.ination of Uranium in Na~~ral· Waters After Anion-Exchange Separation

Source: J. ~orkisch, L. G!Sdl, Analytica Chi.mica Acta, !!.• 113-121 (1971J).

Sample Type: Natural waters

Procedure:

Solution Pre para ti.on:

l. Pretreatment solution - add 1 ml of concentrated HCl to

-.

100 ml of distillEd water. In this solution dissolve 0.5 g of ascorbic acid and l g of potassium tiliocyana1:e.

Ko'te: This solution should be prepared a few ~Ou.:"S prior to use and has a shelf-life of only 2-3 days.

2. THF - MG - HCl mixt:ure .- 200 ml of 3olution should be prepared per separation, and larger ~uantities may be prepared since this solution has a indefinite shelf-life. The mixture ·is prepared to be SO vol.\ tetrahydrofuran CTHF), "O vol.; \methyl glycol CMG - monomethyl ether of et:hylene glycol) , and 10 vol. \ in 5 ~ HC!. Ti1is solution should be prepared at least several hours before use.

Column Preparation:

l. ~ g of Dowex 1 CSio-Rad AG 1-XS, 100-200 mesh, chloride form) .anion-excha..~ge resin is slurried with a few milliliters of the pretrea'tment solution (des'°rii>ed above·).

2. After allowing to stand for lS minutes, pour into an appropriate size column. .

3. Wash the resin wi'th SO m1 of the pre'trea'tment solution.

Separation Procedure:

l. To a 1 liter ~ater sample, acidify with l~ ml. of concentrated HCl.

2. Filter 'through a. dense filter.

3. Add 5 g of ascor~ic acid and 10 g of potassium 'thiocyanate •.

11. Hix thoroughly un'til all reagents have dissolved.

s. Allow to stand 5-6 hours.

Robert•/Chopp1n/W1ld page 27 .

s. ?lace the sample solution on the colwan and.allow it to pass throug.h a:t a rate of 1.2 - 1.3 ml/min (corresponding . to the back pressure of the resin bed). · ·

7. Wash the column· with 100 ml of the THF-KG-BCl mixture.

8. Wash the column with 100 ml of 6 M HCl •. -9. Elute the uranium with SO -1 of l K HCl.

Determination of Uranium:

l. Prepare an aqueous O.l\ solution of arsenazo.III.

2. Evaporate the uranium-containing elute to dryness on a ste._., bath.

3. Take up the residue ir. 5 ml of 9 M hydrochloric acid (added in portions> and transfer to a SO-ml. wide-neck Erlenmeyer flask.

4. Add exactly 0.550 g of zinc and cover the flask loosely with a stopper.

5 • Shake the flask carefully until all of '· i.~ zinc is dissolved.

6. Immediately add 0.15 g of oxa~ic acid and a.so ml of the arsenazo III solution.

7. Measure the absorbance of the solution of .665 nm against a reagent blank prepared in the same manner.

8. Prepare a calibration curve Cl-1~ ~I of ·ura.~iwr: range) •nd obtain the sample uranium concer&tration by comparison.

Note: The a.bsorba:nce will remain constant for at least 30 minutes. The following articles contain related informa'tion on 't't:.is procedure and its development.:

neetermination of Uranium in Geologic Specimens after the Separation of the Uranium by Anionic Exchange" by J. Korkisch and I. Steffan, Hikrochimica Acta~ 1972/6, 837-860 (1972). "Determination of Small Amounts of Uranium. after Concentration by Extraction and Anionic Exchange in a Tri-n-octylphospbine Oxide Solvent System" by J. Korkisch and W. Koch, Milc:rochimica Acta, 1973, 157-168 (1973). "Anionic Exchange Separations· of Elements which are Extractable with· Tributyl Phosphate VII" by J. Korkisch and w. Koch, Kilcrochimica Acta, 1973, 865-875 (1973).

PROCEDURE 9

Rob~rts/Choppin/W1ld

page 28

U'ra...'1.ium Analysis.-by Liquid Scintillation Counting

Source: w. J. McDowell, J. F. Weiss, Health Physics, 32, 73-82 (1977).

Scw::.ple Type: Bone and tissue samples. CThis procedure can

Procedure:

be adapted to other sample types; these modified procedures are referenced).

Sample Preparation:

l. A. for small bone or tissue samples (

Ro~· rt a I Chopp in/Wild page 29

~he perchloric acid and salts. Add 2 :U of saturated AlCN03>3 per gram of sample to ~he hot solution and add water to make S ml of voltm~ per gram of sample.

Counting in All-Purpose Scin~illator:

160 g 10 g

O.l g 385 ml 385 ml 23) 21.

naphthalene PPO (2,5-diphenyloxazole) POPO? (2,2-p-phenylene-bis-S-phenyloxazole) xylene dioxa.ne

lOOJ ml ethyl alcohol Triton X-100

l. Up to : ml of aqu~ous sample solution may be taken up in the scintillator CvolUBe approximately lS ml).

2. The alpha peak of interest must fall within the pulse-height range observed. This can be deTermir.ed two ways:

A. The peak may be located by counting through a narrow-ro:.~e window and scanning across the entire available-range.

B. A multichannel analyzer can be connected to the scint:ill-ati~n counter. (This technique has the additional benefit of allowing visual diff ~rentiation of the alpha and beta-gamma spectra).

Vnless each sample has a very similar matrix, the alpha peak posi~ion mus~ be determined for each sample.to maintain reproducible counting efficiency.

3. Typical background count rates run at:-ou't 20-30 cpm with an additional 10-20 cpm (from .. OK) per each gram of tissue in a sample. The practical lower limit for coun~ing should be a total coun~ of at least twice the background.

Counting in an Extractive Scintillator:

Extrac~ive Scintillator:

161 g so g

.. g

l l.iter

HDEHP Cdi{2-ethylhexyl)phosphoric acidl naphthalene PBBO C ~-" '-biphenyl;rl-6-phenylbenzoxaz·ole) or 5 g PPO (2,5-diphenyloxazole) toulene

l. Transfer the sample (prepared as described under part 3.C. of the sample preparation section) t:o a s

Roberc•/~?!n/Vlld P•se 30

2. Add lQ ml. o~ the ertractive scintillator and shake for· l to 2 minu1:es.

3. Allow ~h• phases to separate

PROCEJJURE 10

Roberts/Chopp1nJV1ld pqe 31

Determination of Trace Ura.niua in Biolo1ical Materials by Neutron. Activction Analysis and Solvent £.xtraction

Source: D. A. Becker, P. D. La !leur, Analytical Clumistry, ~ •. 1508-1511, (1972) ..

Sample Type: Solid biolo1ical u:terials

Procedure:

Irradi&tion: . .

1. Lyophilize and store·the samples· in a dessicator before use.

2. Weigh the samples (200-~50 mg) and encapsulate in a cleaned polyethylene snap-cap vial.·

3. . Encapsulate an uranium standard· Ca soluti:>n cf NBS Standard Reference material No. 950a Uranium Oxide cu3o8>, 99.9~\ purity.J, consisti."\g cf l ml of 1.02 iADl U/llll..

~. Attach copper foil flux monitors to all samples and the standard for flux normalization.

5. Irradiate the samples and standard , and 1-2 mg o! vanadium as a catalyst. 1-2 mg of chromium should also be added ~o indicate when. all of the organic matter is destroyed. The green-orange CrCIII>·• CrCIV) color c~ange

·usually occurs in 6-10 minutes.

Cool the samples, and dilute to 20 ml with 9 K HNC3 • The final sample so~ution should be ca. ·a K in HN~3 ana l ~in HClO".

E:.c:'traction:

Note: The extractions are done in 35-ml polycarbonate centri-fuge_ tubes using O. 75 K HDEHP. (di-C"2-ethylhexy)-phos-phoric acid in petroleiim ether.

Roberts/Choppin/Wild page 32

1. Add 10.0 ml of HDEHP solution to ~he sample in ~he ce.ntri!uge tub• and shake vigorously for 60 seconds.

2. Centrifuge the samples for 2 minutes to separate the phases.

3. Remove the· aqueous phase with a disposable pipet and discard.

~. W•sh the organic phase a~ least once with 8 ~ HN03 and disc·&rd the wash· soiution.

S. Strip the uranium from the orga:U.c phase with l~· H HF, sr.alc:ing vigorously for 1-2 minutes.

6. Remove the aqueous phase Cor an a:..iquot, depending on acti~ity) for coW?ting.

tounting:

l. Counting is performed with a large volume GeCLi) detector and 14096 chanr.el pul:;e height analyzer to meas~ire the 7·S keV 11 'U gamma ray •.

2. A small aliquot (50-250 ulJ of the vanadium standard is diluted to an 3ppropria~e volume (corresponding to the final volume ·of the samples to be counted). During this diluTion, several milligrams of dissolved inactive w.•anium carrier should be ·added to the standard solution to prevent loss of the radioactive uranium.

Yield: 94 + ~\. Slightly higher yields ~ay be obtained by using separat'-.>ry funnels for the extractions . Cfor lower mechanical losses), bu~ this method increases 'the time required for phase separa_tion.

?ROCEDURE ll

Roberts/Chc~p!nl~!ld

?•g

I/. New Heptunium Procedures

INTRODUCTION

Roberts/Choppin/Wild page let

Neptunium is usually encountered . ._s ~ 17 Hp {tis = 2.lli x 10 6 y) in acid solutions of uranium reactor fuel el~~ent:s. Nept~~ium-237 is of relativel.y little use commercially excer>t, pessibly, for 'the production of pure sources of 2 ,.Pu Cbv reactor neutron irrad-iation) and of 2 3 1 U (the e&-decay granddaughter of 11 'Np). Th~ amount of 2 J 7 Np in the environment generally is so small as to be unmq!asurable as compared t:o 21 'Pu, and no procedures were found for separation of Np from environmental samples.

Neptunium-239 is a transient species in reactor fuel elements, due to its short half-life C2.35d). It completely disappears shortly after the end of a neutron irradiation through decay to 239 Pu. Neptuniun-239 is most frequently used as a tracer to study the chemistry of Np; it: can be obtained from the neutron irradia-tion of 211 U or by milking a sample of 2 ~ 1 Am with which it is in equilibriwc as the a-decay daughter.

Two procedures are described for the separation of Np. The first: involves separation of ~- 19 Np from irradiated 2 11U, and the second involves separation of 217 Np from a solution representing that from a dissolved fuel element.

Rob:ozE'tz/Ch~pin/~il@ p@g~ 35

Ch~cwu,to·g::»~tphic S~p~r',~:t:ion iof N~pt:unium th~ing Quat®rr~ ~onium Ni ~a·te Exttiac'ta..~t

Soui""'C~: Vo K~ WM'!rkov, As W. Usolkin, and A. Ie Ternovskii, Radiol\'"ldmiya 21, 862 (1979) $

S~pl~ Type: A 100 ~I s.ampl

PROCEDURE 2

Robert•/Chopp1n/W1ld pag~ 36

A 5;:..ec'".:rophotometric He'thod for th~ Determination of Neptunium in Process Solutions

So\irce: ?. R. Yasudeva Rae and S. K. Patil, J. Kadioanal. Chea. :.i.2 399 (1978). _,

Sample Type: 5 ml of a l H HNO solution containing about 100 mg U, 0.25 mg Pu, ana 0.50 mg Zr in addition to -1 ~g/ml of 111Np. · .

Procedure:

l.

2 .

3.

~.

s.

6.

7.

8.

9.

10.

To the sample solution in a test tube add a known amount of 219 Np tracer solution into the aqueous phase.

Separate the·aqueous ph4$.~ containing the NpCIV) and evaporate to dryness.

Redissolve the MpCIY) in+lO ml of ~ solution 0.1 M in HN03 and -0.l !·in each of Fe 1 and hydroxylam.ine hydrOcbloride. Add· 5 ml of the TTA solution in benzene and reextract for 10 min.

Separate ·the organic phase·, discard the aqueous phase and strip the Np(IV> into 5.or 10 al of 5 M HN0 3 containing S mg/ml of sulfuaic acid and 0.1 q/ml-Arsenazo III. .

11. Mea&~"e- the optical density· of the solutio· at 665 nm with a BecJcasn DU, using l cm fused·silica cells. Compare with the absorbance from a blank •~lution of 5 M HN03 containing 5 q/ml sulfmaic acid and 0.1 mg/al Arsenazo XII. Measure the chemical yield by coaparing the y activity of the 111Np in the sample qains1: that of a ·_known solution of 111 Np

.Roberta/Chopp in/Wild page 37

No'te 1: z "Np can be obtained by ei thar irradiat:in1 2 11U in a reactor or by milking it fraa a saaple of 2161 M. Ca.a the a-decay daughter).

Note 2: Only " ml is reaoved to avoid inclusion of any aqueous phase.

Note 3: Beeris law for the NpCIV)-Arsenazo III complex holds a:t lea.st: up to l. S iig NpCIV) per ml; if H PO is added ~o the a.bsorba~ce solution to naik 'he Arsen&zo III complex with Zr, a separate cali-bra.'tion curve for mea.suri•~!t the NpCIV) absorbance using H3PO~ must: be obt:ainea.

VI. · Nev Plutonlua Procedures

INTJlODUCTIOll

aaberts/Choppin/Wild pag~ 38

Since 1965 1 when the original aonop"&ph on the radiochemistry of plutonium vas published (1) 1 sisnificant changes have occurred in the radiochemical separation and determination of plutonium. Since the advent of a worldwide interest in ecololY in the early l970's, much attention has been directed at deterainin& plutoni\111 concentrations .in the environment: human and animal tissue, plants,_ the atm0sphere 1 and natural waters. These aeasurements involve the de'tection of extr-ely sllal.l concentrations of Pu in relatively larse matrices~ e.1. 1 liters of water or.kg of ti£sue or soil and sediments. This rt:quires t!le reduction of the sample and the quantitative concentration of the Pu to attain aeasura.ble levels of activity free from interfe~ing activities of~~n in signif ican'tly greater aaounts Ce. g. , natural uranium and thorium· and their daughters).

Separa'tions procedures have been improved since 1965 by an increase in the number and quality of solvent ·extraction reagents which are ~~ailable comaercially. Many of the procedures presented in the original monograph employed a solven't extraction step for the purification of the Pu activity; most of these used either thenoyltrifluoracetone CTrA> or tri-n-butylphosphate CTBP>. Nov available are_ such reagents as di-, tril.auryl41line CTI.A), tri-n-oc'tylphosphine oxide CTOPO>, and tricaprylmethy.iamine (Al'!.quat-336). Co\lnting methods have similai·ly improved with the introduction of the silicon surface-barrier detector for a pulse-height analysis, replacing the more complicated and considerably more expensive Frisch grid with essentially no loss in counting efficiency or peak resolut,ion.

The proliferation of nuclear power reactors throughout the world since l96S h&s also led to the develo~nt of a great many procedures for the separation of Pu in.macroscopic concentrations from other acti.nides and fission pi'oducts resulting fraa the dissolution of uranium reactor fuel elements. · These are r.ot considered amona ":he p?"ocedures for this monograph since they se.nerally do not lend.themselves ~ell to a laboratory-scale separation, but rather are relevant to a procP-ssing-plant

. operation with &ll the attendant precautions against radiation hazards and leakaa• of radioactivity into the environment.

DISCUSSION or THE PROCEWRES The procedure• presented herein reflect the interest in

measurins plutonium concentrations in the ecosphere arisin& pria-arily from two sources: fallout from the large nuaber of atmos-pheric nuclear weapons tests conducted prior to _1963 by the United

Roberts/Choppin/Wild . paae 39

S"ti!.t'!";;., ~he United Kinadom, and the Soviet Union and since thenl ~Y the Chinese and the Fl"'Onr.Jt; and the in~:"'Oduc~io" of small a.mounts of Pu to the enviro1a1Jnt through the diachaqe of decontaainated low-level vute •.olutiona by proceaain1 plants and other laboratories eaployins r.adiocheai.cal techniques.

With the exc•ption of Proceurea 7 and t ~IW ~•11ow$,q lllM!'thods all use solvent extraction, by either batch separation or column chroll&tography, as the main pur~ication-concentration step. Procedures l - 7 use electrodeposition of the sample . followed by c pulse-height· a.n&l.ysi~ for the Pu d•terai'l&tion; procedure 8 wses absorption spectrophotataetry and procedure

. 9 uses standard scintillation countinc. Electrodeposition is generally carried out from a solution of •pnoniua chloride or aaaonium sulfate; procedures 1-6 offer ·,semi-detailed descriptions of 'the process. See the Reference l for & more detailed des-cription of the electrodeposition cell and conditions affecting the plating of Pu onto a metal disk. Occasionally, Pu in warm or ho't HN03 can be oxidized to the VI state which is no· retained, subsequentl.y, on an anion resin column. The use of H&N02 in · _these procedu~s ensures that Pu is present in oxidation s~ate III. .

A word of caution: at higher pH values (> It), PuCIV) .tends to form & hydroxy-polyaer which cannot be easily ~estroyed and which behaves differently from Pu species in higher acid con-centrations. _Methyl red in4icator, used for adjusting ~he salt and acid concentration in the electrc.~lating solution, has a pH range of ~.4-6.0 for the equivalence point color change. If the solution remains too long at t.he yellow (basic) color, this hydroxy-polyaer of Pu could form, thus severely reducing_the electroplating yield. Tne use of methyl oranae CpH range 3.l-4.4) as an indicator· might serv.e.. to alleviate this potential dang~r.

Much recent research in plutonium chemistry· is reviewed in the papers in Reference 2.

REFERENCES

l. K. W. Puphal and D. R. Cilsen, Anal. Chem. !.!_, 28:. (1972).

2. "Plutonium Che•istry", ed., W .. T. Carnall C"nd G. R. Choppin, ACS Symposiua Series 216, Am. Chem. Soc., Washington, D. c., 1983.

PROCEDURE 1

~nbert~/Choppin/~ild p osge 40.

Liquid-Liquid Ex-traction Separation and DetenU.nation o: Plutonium

Source: R. P. Bernabee, D. R. Percival, and r. D. Hindman, Anal. Chem. _!!, 2351 Cl980).

Sair.ple Type: Soil Samples Cl-10 g), filters, dnd water samples

Procedure:

(< 0.5 1) which have been decocposed and leached. Thi lanthanide-actinide speci~s ~ave been carried on a precipitate of BaSO ·. C see :\.a! s. a and b fer · a description of the Bas~~ precipitation procedure>.

l. Transfer the BaS04 precipitate with a suitable amount of Pu chemical yield tracer to a porcelain or pl"atinum crucible.

2. Add 30 =l of 72\ HClO~ and dissolve the BaSO~ with a minimum amount of heating. Cool the solution to room temperature.

3. Transfer the solution to a 60 ml separa~ory fur.nel ~ontaining 10 ml of 15\ HDEHP in n-heptane. Extra.c't for S min·.

4. Wash the organic phase twice_ with S ~l portions of 72\ HC104 •

S. Strip the .lantha.nides .:ind actinide£ fro: ~he organic layer with two 10 ml porti~ns of 4 K HNO] for 2 min each• the first 10 ml portion :should -contain r ml of a 25\ NaM02 solution.

6. Wash the organic layer for 2 min with a solution containing 10 m\ of 4 ~-HN0 3 and 2_m.l of a hydrazine-sulfamic acid solution (Note 11.

7. Strip the plutonium from ·the organic phase for 5 min with a solution containing 10 ml uf ~ H KHC 3 , 2 ~l of hydrazine-sulfa.mic a.cid solution 1 and 5 mI of D. 2 K di-tert-butyl-hydroquinone

Robert I? /Ch('¥P:!.n/Wi ld ?

PROCEDURE 2 .

Roberts/Choppln/Vlld page 42

Iietermin&t:ion Qf Plutonium in Sediments by Solvent Extraction

Source: N. P. Sinsh, P. Linsalata, R. Gent:ry, and H. E. Wrenn, Anal. Chia. Acta 111, 265 (1979). -

Sample Type: River-bOt:t:cm sediments.

Procedure·: ·

l. Dry the sample in air. 1:·rush to u."liform ~icle size, and weigh out a 20 1 aliquo~. Add 2-3 adpm of 2 - 1 Pu tracer C Note l > to t:he surf ac·e of t"n1: sediment sample in a fused quartz baking dish.

2. Heat: sample in a. muffle furnace at ~oo0 c for 2~ h t:o destroy organic matter; cool to rooaa temper"atur..

3. Leach the sampl~ with ~oo·m1 of a solution of 3 parts _cone. HMO] and l ;tart cone. HCl. Filter the sample through What:man na. 112 paper. .

~. Repeat: step 3, combine.t:he.leachat~s, and discard the sediment residue and filter paper. ·

S. Boil the leach.ates down to a vol\Ue of 100 ml, cool, and dilute to 300 ml with distilled, deionized water. Precipi-tate iron hydroxide.by.the slow, careful addition of concentrated a.11111onia solution.

6. Centrifuge the precipitate and discard the aqueous supernatant. Wash the precipitate vith dilute ammonia so!ution·C-1/20 of con~entrated) as many times as is neces•ary to eliminate SO~-.aa d•termined by adding BaC12 to a few al of the washl.ftl supernatants. . .

7. Dissolve the precipitate in a minimum volume of cone. HN03 • Add -200 as of HaN02 , heating the solution gently. Cool th~ solution to room ~eaipera~ure, and adjust the acidity of th·e solution to 8 !! by adding cone. HHO 3 .

8. Transfer the solution to a 500 ml sep.ratory funnel.· Add an equal vol\88 of 20\ trilaurylaaine CTI.A> in xylene, whic~ has been prt1equilibrated with about 20 lil of 8 K HH03 •

9. Shalce 1ently for about 10 min. Separate th• phases, remove and set aside the orsanic phue. Extract twice nore vith equal voluataa of Tl.A-xylene. Discard the aque~us phase~

10.

11.

12.

13.

l~.

15.

lE.

!lobercm/Chopp1n/V1ld pego 43

Collbine the o:rau.ic ph&sea into the ••p&r&tory funnel. Add an equal vol\11119 of 10 H HCl and sh&ke gently for S llin to ruaove· tracu of Th. !Siscard the aqueous phase.

S~• the organic phase twice CS lllin each) wit:h equal voluaes of 8 !! BH_o3 to remove uraniwa. Discard t:h• aqueous phuas.

B&ck-eztract the plutoniWI. with an equal volume of 2 M B2S011 , ahaking cent:ly tor 10 ain. Repeat- twice more and ccai'ine the aqueous back-ertraetant: solut:icns in a. beaker.

Evaporate the back-eztractant solution to dryness and cool. Destroy residual oraanic matter by adding several drops of cone. BN03 and lO\ e2o2 ; evaporate to dryness. Dissolve the residue in l al of 2 K a2s'o4 .. an~ transfer to a plating cell. Wuh the beaker twice aore with l· Ill portions of 2 ! H2so .. ·and transfer t-hese to the plating cell. Add l drop of methyl red inciica.tor. Ad:! cone. ammonia dropwise until a yellow color appe&rs. Quickly add enough drops o~ 2 ~ H2S011 to restore the red color and· electroplate at a curreftt of 1.2 A for one hour.

Quench the electr:>deposition with 3-q drops of cone. ammonia at the end o! the platin1 porcess; l'f!IC.OVe the planchet and wash vith distilled water and al~ohol. Flame ~o redness over a Bunsen burner. Use a-spectrometry to determine Pu is~~opic compo~ition·and yield (Note 2).

Note 1: Uranium in the sediment may accompany the Pu · thro\6gh the extraction procedure in amounts s~fficient such that the 21 •u a-pe~ at ... 77 KeV may interfere with the 2 - 2 Fu a-peak at 11.90 KeV. If this is the case, more 2 • 2 pu tracer than that indicate~ must be Added.

Note 2: The average Pu chemical yield for 11 measurements was 35\ 1 with a range of 7 "to 71,. Amounts of Pu down to a few pCi per dry kg of sediment can ·be measured~

Source:

PROCEDURE 3

Rohe :t '/Choppin/Wlld page 44

Radiocheaical DeterainAt!;~ of Plutoniwa in Karine Samples by ~tr~ction Chromatography

A. Della Site, U. Marchionni, C. Testa, and C. Triulzi, Anal.· Chim. Acta·~, 217 (1980).

Sample Typ.s: (&) sea water; (b) sediments.; Cc) marine organi911:5

Procedura:

1. Prepare two extraction slurries by adding dropvise, with stirring, 2 Ill of 0.3 M tri-n-octylph~sphine oxide CTOPO) in cyclchexane to 3 g of Kicrothene or Kel-F powder. Add 30 ml of ~ H HN03 and stir for 30 min. Transfer one of the slur":"ies to-a glass chromatographic column.

2. Pretreatae~t of samples:

a) Set water: to SO 1, add 10 ml of a solution of SO mg Fe 3 ml_,. in 0.5 M HCl and -1 adpm of 21112 Pu or 231 Pu tracer. Stir and-add 200 1'-l of 2 K NaHSO , follwed by enoug~ cone. ammonia to give an alKaline iH. Let the precipitate stand overnight. Siphon off· the solution9 centrifuge the precipitate, and dissolve it in the minim~·. quantity of cone .. HMO 3 • Add 100 ml of 8 H HN03 and 5 ml of 30\ H20 2 , and heat the solution to boi!ing. Dilute · to 1 1 w~tn ~ ~ KN0 3 , add -lC g NaN0 2 in water, and stir for 15 min.

b) Sediments: dry the sediment at 105°C to constant weight. Add -2 . CMipm of z 1111·2 Pu or 2 u Pu tracer to 100 g of sediment and leach by boiling_ with 600 m.l of 8 K HN03 for 3 h. Filter ~he solution and repeat the leaChing procedure twice.more. Combine the leachir.gs, add 25 ml of 30\ H2o2, and evaporate t:he solution to 500 ml. Dilute to l 1

_with distilled water, and -10 g of NaN02, and stir for 15 min. ·

c) Karine organisms: dry the sample at lC5°C t'o con~tant weight:.· Add -2 Cldpm of 2 • 2 Pu or 211 Pu tracer t:o 300 g of dry sample.and he&~ in a muffle furnace at ~S0°C for S h. Cool, add 50-100 ml of cone. H.N03 and 10 ml of 30\ H O , and dry under an infrared laap. Heat again in mu!fli furnace at ~S0°C. Repeat the wet and dry aineral-izat:ion to give a carbon-free residue. Dissolve the · residue in 500 ml of 8 K HNO , bo~l, filter, and dilute t:o 1 1 wi'th water. A~d-2.S j of NaN02 and stir for 15 ai.n.

3.

~.

s.

6.

7.

8.

Roberts/Ch~pJn/W!ld . ;:age r.~

·Add the re.na1nin1 extraction slurry to the aaapl• solution ( -~ K in ilNO ) and stir for l h. Filter on • Buchner funnel and transfer l~e slurry containin1 the Pu

PROCEDURE i.

Robert~/Chopp1n/W1ld page 46

!he De~ermination of Plutonium in Environae~tal Samples by Extraction with Tr_idodec:ytamine

Source: J. C. Veselsky, Int. J. Appl. Radiation and Isotopes !.!· a.gg (l9i6).

Sample Type: Soils

· .........

Procedure:

1. Add 10 ml of water containing a suitable smount of 211 Pu ~racer to SO g of air-dried soil in a porcelain dish. Afte~ drying .the tracer solution, ash the sample at 50Q°C for several hours Cor overnight).

2. Soil the sample for 3 h with 200 ml of 8 H HH03 including -1 g of Na.NO ." Cool .:.nd decant-the sol~~~o~ into a 250 ml centrifuge gfass and centrifuge for 10 l!'l.i.11.

3. Transfer the nitric acid sclution to a 500 ml separatory funnel &nd extract twice CS min eac~) with ~O ml portions of 25\ tridodecylam.ine CT!.A) in x;lene which has been preequilibrated with 8 ~ HN03 •. · ...

5.

6.

7.

8.

9.

10.

Combine. the organic extrac~s. centrifuge for S min and discard any aqueous solution. Transfer the organic.phase to a 250 ml s~paratory funnel and Jash with 2s· ml of 8 M HN03 (3 min). Discard the aqueous p~ase.

Centrifuge the orsanic phase for S min and discard any aqueous solut'ion.

Wash the organic phase 3 times with 25 ml of 10 tt HCl ·(3 min each} in the separatory funnel, discarding the aqueous phase each time. ·

Strip the Pu.by shaking the organic phase fo~ 5 min each with nro 80 ml portions of a soluti~n of 30 ml cone. HCl + 0.3 ml cone. HF in 1 1 of water. Wash the combined aqueous back-extractants with 50 ml of xylene.

Tr~sfer the aqueous ba~k-extractant to a Teflon beaker and ev&!"=rate to dryness under a heat lamp.

Dissolve the reaidue in 5 al.cone. HN~3 , add S drops of 30\ a2o2 , and evaporate to dryness again. Dissolve the re•idue in 5 al of cone. BCl, evaporate to dry-ness, and di•solve the residue a.1ain in 5 ml of cone. HCl + ~ ml of 3.2 !!. HH~Cl solution. Evaporate to dryness.

11.

12.

13.

Kobert•/Choppln/Vlld ,... 47

Dissolve the dry NH Cl residue in 3 Bl of water and tr&nafer t:o an electropl&tir.~ cell. Wuh th• beaker vi th l ml of . water and add this to the cell.

Add l drop of aethyl violst indicator and electrolyze for a.bout 20 min at 111 Y And l.S A. Add Z ml of cone. aaaonia solution t~ the ·cell &!)out 1 llin before the end cf electrolysis wi t:hout interruption of the current. ·,

R6Jll0ve the pli'lnche~ frcm. the cell, wash with water and dry under a heat laap. Determine the Pu isotopic content and chemical content by a-spectrometry (see Note).

Note: Chemical yields for aoil samples ranged up to 70\i for plant ashes, > 90\ ~ield was obtained. Sensitiv-ities dow:n to 0.1 pCi z 'Pu per SO g of soil can be obt:ained.

PROCEDUJU

Robert•/Chopptn/Vild p•ge 48

Solvent Extraction Hethod f~r Determ.ination of Plutoniu.m in Soft Tissue

S~urce: H. P. Singh, S. A. !brahim, N. Cohen, and H. E. Wrenn, Anal. Chll!lll. !2_, 357 (1978).

Sample Type: Soft Tissue

Procedure:

l.

2.

3.

...

5.

6.

7.

8.

~c 500-1000 1 of tissue in a 11 1 beaker, add 1-2 Cldpm ef z-zPu traeer and enough cone. HN03 ~o just cover the tissue.

Heat gently over a mag~etic stirrer hot plate until frothing ceases. · Raise the temperature to lOODC and heat until the· volume is -lOO ml.

Increase the te=peranJre and add a few drops of cone. HH03 occasionally until the solution is clear.

Add 200 m.l of an eq~l-volu.De mixture of cone. HN03 an~ cone • H SO~ And heat vigorously until all the nitric acia is d~iven off. Add a few drops of cone. HNO occasionally with constant heating until a clear colorless iolution is obtained. Remove most of the sulfuric acid by evaporation before pro-ceeding further. ·

Add 300 ml of 11 H HCl to :he clear solution and boil for se¥eral minutes.- Cool and add 1 ml of Fe carrier (100 =i Fe 1 ); swirl the be&Jcer for proper mixing.

Add cone. ammonia solution gently until the ?recipitation is complete CpH > 8). Gently heat the precipitate with constant stirring and allow to stand overnight.

Se~ara~e the precipitate from the supernatant by centrifug-ation ui a SO ml centrif~ge cone. Dissolve the precipitate in a 11-s ml of cone. HHO.,,. a:1d reprecipitate the iron hydrox-ide; repe~t the process ieveral tiln~s to ensure the COlllplete removal of the sulfate ions Ctes~ the supernata~t for SO~-z with BaC12 solution).

Dissolve t~e precipitate in ~ cir.im.um volume of 8· ~ HN03 and adjust the HH03 concentration to 3 H.

9. Heat the solution gently dnd add 25 mg of NaN02• Cool the solution to room tempe~ature.

10.

ll.

12.

13.

11+.

15.

16.

17.

lB.

19.

Robert•/Cboppia/Vild , ... 49

Add &n equal volume of 25' 'trilauryl.aaine ('!'LA) in xylene vhich has been preequilibrated with ~ K KHO for 10 min CHote l). Sh.Jee aent:ly for 10 ain and-cent~ifu1e to Hpar&te th• phu••· .

Remove the aqueowa phue into another 50 Ill centtifua• cone and repeat the extraction uainc a freah ponion of TLA extractant.

Combine the organic phas•s and was~ for 10 ain with an eq,ua1 volume of 10 M HCl. Centrifut:• to separ.atc the phases. Repeat this vi':ahing to insure removal of Th.

Wash the organic phase with 8 ! HH03 to remove Fe and U. Stri? the Pu from the organic· phase vith ~n equal. volume of 2 Ji H SO , shakina for 10 m:in. Remove the aqueous phue and rej)ea~ tke stripping ~ith 2 ~ H2so_. Combine the aqueowa back··extrectant solutions. · Evaporate the solution to dryness.

For electroplating, &dd l ml of 2 K H SO to the beaker, heat 1ently, and transfer to the efeci~eposition cell. Repeat with two aore rinses of.l ml of 2 !!. H2so_. A~d 1 drop of methyl red i.Ddicator and titrate dropvise with ammonia to a yellow color. Restore the red color with ~ minim.um amount_ of 2 !!. H2So_. Electroplate at 1.2 A for l.h. At the end of~ h, just before the current is shut off, quench t~~ electrodeposition by a~ding severa..J. drops af. ammonia.

Remove the planchet, rinse with water and alcohol, and flame to red heat. Determine the Pu isotopic compositicn ar.d chemical yield by a-spectrometry CNo~e 2).

Note 1: The 25\ solution of TLA in xylene which has been equilibrated with 3 !!. liN03 must bP. prepared fresh ea.ch day.

Note 2: Pu recovery ran1ed froa 1+9 to BS\ with a mean of 61\. Sensitivities as low as a few fCi/kg tissue can be obtained.

PROCEDURE i

·Robert•/~ia/Vlld P•ll! 50

Detenaination of Plutonium in Tissue ~Y Aliquat-336 Ex-traction

Sou:-ce: I. H. Fisenne and P. H. Perry, Ra.diochea. Radie&nal. Let~!!· 259 (1978).

Saaple Type: Human or ani:u.l tiss'iJe

Procedure:

l..

2.

3.

...

s.

6.

, ..

8.

A weighed amount of tissue is wet-ashed in con:. HN03 containing a known amount of 2 • 1 Pu tracer to achieve· destruc-. tion of the oraanic zaa.terial. Evaporate the solution just to the point.of dryness.

Ade! lCO ml of 8.5 K HNO to t:he sample and warm to 8il°C to effect complete-dissilution. Add 25 mg of NaHO, to convert the Pu to the IV oxidation state. Continul wa~i.,g to remove excess nitrate.

Cool the solution to room temperature. Withdraw a 100 u1 aliquot of the •olution, add to 25 Ill of distilled water, and titrate to the phenolphthAlein end point with O.l N NaOH. If the HNO concentration is ben1een a and 8.7 N, proceed to step ~. Il not, adjust the concentration to 8.~ N with either distilled water or ccnc. HH03 , as required7

Prewash a. 30 vol \ Aliquat-336 in toluene solution three times with equal volumes of 8.S H HHO • Add two SO ml portions of the Aliquat-336 solution ~o each of two 250 llLl separatory funnels. Add 300 ma of Ca(N03>2dissolved in 8. 5 !. HN03 to the first separato.:-y fuMel. Transfer the sample with washes to the first sepa-atary funnel and shake for 3 min. Separate the phases and draw off the aqueous phase into the second separatory funnel.

Shake the second separatory funnel for 3 min and separate the phases. Discard the aqueous phase.

Combine the extract11nt phases into a separator-~ f\UU\el and wash twice for 3 ain each vi't:h equal voluaes of a·. 5 N HH03 and tvice for 3 ain each with equal volum.s of cone. HCl. Discard all of 1:he acid washes.· .

Strip the Pu froa the Aliquat-33• with two equal-volume washes of l N HCL/O.Ol N HF soluti~n. Ccabine the aqueous strip solutions. -

9.

lO.

ll.

Roberts!Choppln/Vild PAI• ·Sl

'•,

Evapor~~e the strip solution to near dryness; add 5 ml of cone. r.!

··.

PROCEDURE 7

Robert•/~happin/Wlld · page 5:'

Determination of Trace Amounts of Plutonium in Urine

Source: J. C. Yeselsky, Kilcrochill. Acta, 1978I, 79.

Sa.mp le T-1pe: Urine

Procedure:

2.

3.

•• s.

6.

7.

8.

9.

To the urine sample (1-1.S 1), &dd 200 rtl of cone. HNO!• ·-1 odpm o! 11 'Pu tracer, and S ml of a calciW:i. ;h~~pha~e carrier soluti"on CHote l).

Heat the solution to 80-90°C for 3 h. Preciptate with SOO ml of cone • ..aonia, decant the supernatant, and centrifu1e the precipitate in a 250 ml centrifuge tube.

Dissolve th• precipitate in the centrifuge tube in a minimum volume of 3.5 ~ HN0 3 &nd add ~ al of 30\ H2o2• Evaporate to dryness in a silicone bath. Repeat steps 3 and ~ until the salts appear white or pale yellow.

Add o.s 1 of solid Hdi02 to the residue, follawec! by 25 ml cf 7.2 !!- HNOl. Heat in a siliccne ~ath until·&•& evolution ceases. Cool. to rooa t-per_ature.

Pass the solution through a l ca diam. ion-exchan1e column of B g 100-200 mesh Dovex l-X2 resin which has been prewashed with 7.2 H HNO!. Wash 3 times with S ml ~rtions of 7.2 K HN03 , !o!lowea by 2 washes with 5 ml of 10 ~ HCl.

Elute the Pu

Robert•/Chappio/Vild pap Sl

Note 3: ?u recovery is usuall¥ > ~O\i the detection liai.t is about ~o fCi o! 11 ~~per liter of urine.

PROCEOOJU: 8

Jtobert•/Cboppla/Vlld pqe S•

Extractive Photometric Deteraination of PlutoniwaCIV> with Aliquat-336 and Xylenol Oranae•

Source: J. P. Shulcula and K. S. Subramanian, J. -Radioanel. Ch-. !!1 29 . (1978).

S&11ple Type: Solutio·n

Procedure:

l. Transfer an aliquot of solution con~ainina u1 quantities of Pu to a ce11trifuge tube conu.inin1 2 ml of " !! HRt- 3•

2. Extract twice with 2 ml. portions of 5\ Aliquat-336 in xylene which hu been preequilibrated wit!': "' H HN03• Extraction time should be abc.at S min. -

3. Combine the ora~~ic cxtractSi trans!er a 0.5 ml portion to a 10 ml. volumetric flask.

"'· Add to the volumetric flask 2 ml of abs~lute ethanol, a.s m.l of 1lacial acetic acid, and 2 ml of a 0.2 v/v \ solution of xylenol Qrange in methanol. Dilute to the mark with absolute etti.J\ol.

s. Transfer an aliquot to a spectrophotometer cell and read the absorbance at S"'O nm •&•inst a reagent blank prepared in the s&11e manner. Compu~e th~ .smcunt of plutonium extracted into the organic phase from a calibration curve.

Ncte: The ex~raction of Pu(IV) into Aliquat-336 in xylene

PROCEDURE 9

&obert•/Oaoppia/Vlld ,... 55

Siaultan•ous Eiiat.rainationa of Plutonium Alpha- and Beta-Activity in Liquid Effluents and En.vircmmen't&l.Saapl••

Source: G. C. llAnds and B. O. B. C~nvay. Analyst!!!• 9311 (1977).

Saa~le Type: Solutions

Procedure:

l.

2.

3.

II•

5.

6.

Transfer not: more than SO Ill of the sample solu.tian into a us ml Erlenmeyer fiuJc:. Add 3 1 of K,so11 • ! al of cone. H2so 11 , and & drcps each of cone. HN03 and &O\ ec10,. · Evaporate the mixture to fumes and fuse over a hi.sh-temperature ~urner

Robert•/Cho>ppln/Wlld P•1e 56

ll. Transfer me eluate to a centz·ifu&• bottle and add l 1lll of the "8 carrier solution. P!'ecipitate by the dropwise addition of 50\ HaOH solution. Centrifuge and wash twice with water, discarding the supernatant and wash solutions.

l~. Dissolve the precipitate a:-.d wash the solutior. into a separatory funnel, usin1 a total of 10 al of 2 H HH03• Add 5 ml of • 25 .vol. percent solution of RDEHP-in n-heptane and extract for S min.

15. Discard the aqueous_phaae and transfer the or1anic layer into a 1laes scintillation countina vial. Add 10 ml of scintillant (Note 1), aix, and cou.~t in a·three-channel liquid-scintill-ation spectrometer. Use two ch&n.~els which have been previously optiaized for counting a and I activity.

16. Calculate the 2 - 1 Pu activity in pCi/1 from the equation

z-1Pu activity =

Vll. Oxidation State Proce~ures

INTRODUCTION

Roberts/Choppin/Wild page S7

Thorium exists in oxidation IV and the ti"allSplutonium actinides are typically trivalent although some use is made of other oxidation states in their separation schemes. Uraniu.m.is most coml!!Only found as UCVI> in the fona of the divalent UO 1 • However, neptlUlium and plutonium. exist rather readily in oxfdation st&tes III, IV, V and VI. Since the behavior in nature of these latter two eleaerts is dependent on the oxidation state or states present in a particu:~ soil or water, a m.sjor problem has been the separation of the neptuniuz. and plutonium &pecies present in a sample without changing the redox equilibria. The next three p:-ocedures are schemes for such separations.

In the first procedure, a combination of selective sorption and solve~t extraction is used to separate Np(IV>, Np(V) and NpCV!). The same procedure works for plutonium.. The second procedu~ uses solvent extraction by TTA with aqueous solutions of different pH values to achieve separation of the IV, V and VI states. Since many natural waters are abo~t neutral, a similar procedure has been developed using diben%.Cyl.methane CDBK> which is less scluble in neutral aqueous solutions than is TTA. This is descri?>ed in Procedure 3 for oxidation states III, IV, V and VI. Th~ AnCIV> is sorbed on the vessel walls in the first extraction but is pla ed in solution by the dilute HCl 41\d extracted sub-sequent:ly.

· PROCEDURE l

koberc•/Chappin/Vild page 58

S.p&ration of Np(IV), Np(V) &nd Np(VI). by Adsorption &nd Extraction

Source: Y. Inone and 0. Tochiyaaa, J·. Inorg. Hucl. Chem. , !!· 1 ...... 3 (1977).

Saaple Type: Soludons

Procedure:

1.. Adjust an aliquot of the Np solution to pH& with acetic acid and/or ..-xiiua hydroxide at a total volume of 5 _ml.. Add 100 1111 silicic acid powder (100 -•h>. Shake occasionally for 30 ain. The Kp(IV) and NpCVI> are 100\ sorbed, leavin1 Np(V) in solution.

2. After separation by centrifu~~tion, &djust the pH to 10-11 and add a fresh 100 II& saap!.• of silicic acid. With 30 ai.nutes occuional shald.n1, the NpCV) sorbs ccapletely.

3. To s fresh aliquot of the Np solution, add &Clo.., to o~tain 5 al s::ilui:ion vhich is l K in RClO..,.

.. • ·Prepare a. fresh precipate .of BaS015

by aixin1 l al each of

~~~~~!N~~2ad~dt:~2N: ::I~~~~n.Af~ro!03~i:In~v:c!~~et• sorption of the Np(!V) ~ith no sorption of H?(V) or Np(VI).

5. oxidation state differentiation can also boe achieved with ..,0\ (v/v) TIP ia benzene. Fraa 3 H HCl solution, after 5-10 min, 90\ extraction of NpCVI) is obtained with . From 6 H HCl solut.1.on, after 5-10 min, 80\ NpC!V) and 100\ NpCVI> but no Np(V) is extracted.·

Note: ·This ae_thod has ~~n used !or plu_tonium. a. lso.

Pu(Y) sorbs on CaC03

PROCEDURE 2

Robert•/Cbcrpp1n/!:!1ld paae 59

Separation of Oxidation.St&~~• IV, V and VI by Solvent Extraction

Source: P. A. Bertrand, G. R. Choppin, Radioch~. Act&, .!!- l3S Cl982).

Saaple Type: Solution

Procedure:

1. A O.S 111.l aliquot of the actinide solution is added to Q.S 111.l of 0.5 H acid CHClO~, HCl, BH03 ) to obtain a pH ca. 0.6.

2. This solution Cl 111..l) is mixed with 1 111..l of O.S H TTA solution in xylene or toluenti and the mixture shaken vigorously for 5 min.

J. The phases are separated for counting; the AnCIV>+ is ~100\ extracted into the TTA solution while the AnCVI) remain quantitatively (>98\) in the aqueous phase (Note l}.

~. A second O.S 111..l of the original actinide solution is added to O.S ml of O.S H sodium acetate at pH-·

S. This solution i~ added to l 111.l of the O.S H TTA solution a..,d shaken for S min.

6. The ph.,ses are separa~ed for counting with essentially 100\ of the AnCIV) and AnCVI) in the organic phase and 100\ of the AnCV> in the aqueous (Note 2).

+ Ar. = actinide element Note l. AnCIII) would remain quantitatively in the

aqueous phase.

Note 2. An would be extracted into the organic phase.

PROCEDURE 3

lo'bert•/CboppinfUild pqe 60

Separation of Dif feren~ Oxidation States by Solvent Ex~action in Keutr&l Solutions

Source: A. Saito and G. R. Choppin, Anal. Chem.,!!_, 2~5~ ll983}.

s..ple Type: Neutral solutions

FLOWSHEET

ample solution CpH-1) 2 a1

I &) add 10 l'!.1 :I. 5 K D!M• ~ b) sh.ake for 10 m.

rsanic phue ueoµs phase

1anic phase

An(VI)

a> add s ml 0.01 K acetate solution pH 5-5-.S

b) shake for 2 •·

ueous phase

An(Ill) An(IV)

a) add dilute HCl ~o lover pH to -~-s.

b) add s ml 0.2 M DBM solution

c) shake for lO m.

An(V)

•Chloroform was used as a solvent to ailov easy removal of the or1anic phase.

Proc ...... :

l. lepu•tioa Of llp(IV) 1 .. (V) .... llp(Vl) bJ Ad9ozpeloa .... l:&tr.cct.oD ••••••••••••••••••••.•.••••••.•.• 51

2. 1..-at:toa of Old.datlon ::c.tu lV. V. ...S Yi by lol~ laamctlon.. • • • • . . • . • . • • . • . • • •.•.•••.......•...... 59

J. lepmratioa of DUlenat O&ldmtloa lutu bJ lol"NDC l:RractlOD 111 leutral Solv.tlom •.....••....... ; •.• 60

fl"

·:'!!fi.~ I ; .....

·_I 86 t ·. ·., ... :. ,.,/

THE RADIOCHEMISTRY OF URANIUM, NEPTUNIUM AND PLUTONIUM-AN UPDATINGTABLE OF CONTENTSTABLE OF CONTENTS (CONTD)I. SUMMARY OF PREVIOUS URANIUM PROCEDURESII. SUMMARY OF PREVIOUS NEPTUNIUM PROCEDURESIII. SUMMARY OF PREVIOUS PLUTONIUM PROCEDURESIV. NEW URANIUM PROCEDURESV. NEW NEPTUNIUM PROCEDURESVI. NEW PLUTONIUM PROCEDURESVII. OXIDATION STATE PROCEDURES