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Cation-exchange separation of cobalt(II) on Dowex 50W-X12
SHORT
COhIhlUNICA’IXONS
393
compounds. Comparison with other fluorimetric its advantages and effectiveness.
procedures
for amines demonstrates
The investigation was supported in part by a National Undergraduate Research Grant GY-Go87 and a Mead-Johnson graduate Research Grant. The Analytical I~ejbartment Sckool
J. T. STEWART D. M. Lo-l-r1
Laboratory, of Medici~lal
Science Foundation Laboratories Under-
Cltewzistry,
of Pharntacy.
University of Georgia, Athens, Ga. 30601 (U.S.A.)
(Received
June 8th, 1970)
Cation-exchange
separation
of cobalt(ll)
on Dowex
5OW-X12
Cobalt is one of the major constituents of fission products, and its separation from other elements has attracted considerable attention in recent years. The scparation of cobalt from nickel has been done on cation-eschange resin KU-I by selective 1. Similar separations of cobalt from iron, zinc, etc., elution with hydrochloric acid have been effected on Dowex-so resin2. A 2(y0 so d ium nitrite solution has been used for the separation of silver from cobalt on Amherlite IR-x203. On the same resin, copper can be separated from cobalt by first eluting copper with a solution of 0.5 M sodium thiosulphate 4. A mixture of 0.5 M hydrochloric acid-acetone has been used for the separation of cadmium, zinc, etc. from cobalt on Dowex SOW-X85. A systematic study of the cation-eschange behaviour of cobalt on Dowcx SOW-XIZ (I-L+-form) with different eluents is described in this communication.
A Cambridge PH meter and an automatic fraction collector (Tower’s type) were used. The ion-exchange column was the same as described previouslyfi and a resin bed of Dowex SOW-Xrz (Dow Chemical Co., Midland, Mich., U.S.A.), ~0-50 mesh, H+-form (I .4 x 23.0 cm) was used. Cobalt sulphate solution (5.067 mg ml-r) was standardised by classical methods7. An aliquot of solution containing a suitable amount of cobalt was sorbed on the column, After the column had been rinsed with IO ml of water, the elution was carried out with various eluents (Table I). The effluent was collected in 25-ml fractions and was titrated with EDTA (disodium salt) 7. Elution constants, E, and volume ,. .I ,..,,. Awzl. Chim. Ada, 52 (1970) 393-396
SHORT
394
COMMUNICATIONS
distribution coefficients, IA, were calculated as beforea. The eluents found to be most suitable, were used in the subsequent separations.
On the basis of elution constants and volume distribution coefficients, the may be arranged in order of decreasing efficiency as follows: N&04= (NH&S04 = NaCl= NH&l = NaNOg c HCl c HNOa c HClO4 < CH&OONH4. Scj3aratiorzs by gradient ehtion. Ions such as zinc, beryllium, caesium, uranium, rubidium, cadmium, lead and mercury are much more weakly bound to Dowex SOWSrz than cobalt. It is thus possible to remove first the unwanted cations with I M
eluents
0.3373 0.632 2
1.Gzg HJSO.~
200
1.0 2.0
7.5 So 40
3 .o ‘I.0
I-INO:1
2.9G5 I.582
0.247 x.123
3.GGr 0.8906
250
101.5
12s 75 *5o 50
200 200 200
100.7 g8.9 X02.1
75 50
2.50
99.6
_T.o-‘\.o
150
100.8
o.G322 1.123
1.582 0.89oG
2.ckt.o
75
200-300
100.3
0.0322
1.582
200
35.0 9g.G 100.5
o.G322 1.123
1.582 0.89oG
0.4398 o.G322 1.123
2.274 1.582 0.89oG
o-3373 0.6322 1.123
2.9G5 1.582 0.89oG
200
75 so 100
0.5 I.0
75 50
2.0
0.5
125
1.0
;z
2.0-3.0
52
0.3373 0.6322
100.0
3.0-4.0
Anal. Chim. Ada,
2,965 1.582 0.8goG
r SJ
1.0
(NH&SO.t
0.3373 0.6322 1.123
101.8
1.0-2.0
a&so.&
200 200
2.0
N
r.Gzg
75 50
1.0
NH&I
102.3
3.0
‘I.0
NaNO:,
120
I ,582 0.8goG o&14 1
3.0 100.4
3.0
NaCI
1.123
250
‘}.O
FT.1
oh322
101.g
‘2.5
4.0
CH:,COON
ro2.G
175 ‘50
2.0
I.0
I-ICIO.~
43.5
2.905 I .582 Oh141
(1970)
393-396
225 150 22s 150 12.5
100.0
275 150 I25
101.8 101.0 100.9
x01.4
99.8
SHORT
COMMUNICATIONS
395
hydrochloric acid and then &lute cobalt wit11 4 M hydrochloric acid (Table II). With some cations, other eluents were preferable: for uranium, 0.5 M sulphuric acid; for mercury, 0.5 M nitric acid; and for lead, 0.5 M ammonium acetate solutions. In these cases cobalt was removed later with the same eluent at a concentration of 4M.
Selective ehtiolz with ovgauic acids. Eluents such as oxalic. citric and tartaric acids in any concentrations are poor eluents for cobalt, but are good eluents for elements such as tin, iron, aluminium, manganese and antimony. Since z M ammonium sulphate has a high elution constant, it can be used to desorb cobalt from the column, after elution of other ions. Thus, 10% oxalic acid was used for the elution of tin, iron and aluminium, while 5% citric acid was used for antimony. It was possible to remove manganese with 10% tartaric acid. Cobalt, in all these cases, was subsequently eluted with z M ammonium sulphate. Selective elzttiort witlz specific eluents. Sodium chloride (I M) was found to be an efficient eluent for cobalt, but not for strontium, titanium, barium and magnesium ; cobalt could be first eluted with r M sodium chloride followed by the elution of strontium and magnesium with 4 M hydrochloric acid, or titanium and barium with 4-G M nitric acid. In the separation of copper from cobalt, copper could be first nluted with 0.5 M sulphuric acid followed by the elution of cobalt with 2 M ammonium sulphate. It was possible to effect separation of cobalt from nickel with 0.05 M EDTA, by taking advantage of the difference in pH; thus, cobalt was eluted with 0.05 M EDTA solution at PH 5.0, and then nickel with 0.05 M EDTA at pH 10.0. Cobalt could be separated from thallium by gradient elution by eluting first cobalt with 2 M sulphuric acid, followed by the elution of thallium with 4 M sulphuric acid. Separation of silver from cobalt was possible by first eluting silver with 2OA, sodium nitrite, and then cobalt with z M ammonium sulphate. TABLE
IL
ION-EXCHANGE
(CObiLlt
talccn
Foreigrb io?r
SEPARATION
=
25.335
An~ocr~rl added
OF
COt3hLT(II)
Wig) Cobalt
Anaottrrt added
Foreign iO?Z
Found
l?ecovared
(W)
(%I
26.2
50.8
25.3 25.4 25.4
Bi Th :It
Sr
51.5 SO.2 25.6 25.2 26.4 76.7 x4.G 75.8
25.3 25.1 25.0 25.0 25.1 25.3 25.0 25.0
100.0 100.4 roo.l# 100.0 99.8 99.6 99.6 99.8 100.0 99.6 99.6
Ti w!
10.0 52.4
25.3 25.4
100.0 100.4
rh20Ja-
Srl(I1) Ni
24.3 24*5
25.0 25.1
99.6 99.8
(W) Zn Be Cs lib Cd Ba
Cu(II) U(VL)a Tl(1) Pba
n
267
(mg) -p_
Zr(IV) Fc(lII) Al Mll(II) H&I 1)” Cr0d2VO.t-
25.2 12.8
25.8 102.3 2G.4 25.0 26.
I
Cobalt -. Found
Recovered
Iw’)
(%I
25.0 25.1 25.4 25.3 25.4 25.1 25.1
99.6 99.8 TOO.4 100.0 100.‘~
99.8 99.8
27.3 2G.g 52.3 43.8
25.0
25.4 25.3 25.4
100.4 100.0
49.7
W042-
25.G
25.1
25.3
99.8 100.0
Mo,Ozsl~-
26.5
25.0
99.6
99.6
100.,+
see text. A?tal.
CJkm. A&a,
52
(1970)
3gp-396
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;IS
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sil\*csr tilliC’5
;1ii11
iIl)llllt
COhIhlUNICA’IXONS
393
compounds. Comparison with other fluorimetric its advantages and effectiveness.
procedures
for amines demonstrates
The investigation was supported in part by a National Undergraduate Research Grant GY-Go87 and a Mead-Johnson graduate Research Grant. The Analytical I~ejbartment Sckool
J. T. STEWART D. M. Lo-l-r1
Laboratory, of Medici~lal
Science Foundation Laboratories Under-
Cltewzistry,
of Pharntacy.
University of Georgia, Athens, Ga. 30601 (U.S.A.)
(Received
June 8th, 1970)
Cation-exchange
separation
of cobalt(ll)
on Dowex
5OW-X12
Cobalt is one of the major constituents of fission products, and its separation from other elements has attracted considerable attention in recent years. The scparation of cobalt from nickel has been done on cation-eschange resin KU-I by selective 1. Similar separations of cobalt from iron, zinc, etc., elution with hydrochloric acid have been effected on Dowex-so resin2. A 2(y0 so d ium nitrite solution has been used for the separation of silver from cobalt on Amherlite IR-x203. On the same resin, copper can be separated from cobalt by first eluting copper with a solution of 0.5 M sodium thiosulphate 4. A mixture of 0.5 M hydrochloric acid-acetone has been used for the separation of cadmium, zinc, etc. from cobalt on Dowex SOW-X85. A systematic study of the cation-eschange behaviour of cobalt on Dowcx SOW-XIZ (I-L+-form) with different eluents is described in this communication.
A Cambridge PH meter and an automatic fraction collector (Tower’s type) were used. The ion-exchange column was the same as described previouslyfi and a resin bed of Dowex SOW-Xrz (Dow Chemical Co., Midland, Mich., U.S.A.), ~0-50 mesh, H+-form (I .4 x 23.0 cm) was used. Cobalt sulphate solution (5.067 mg ml-r) was standardised by classical methods7. An aliquot of solution containing a suitable amount of cobalt was sorbed on the column, After the column had been rinsed with IO ml of water, the elution was carried out with various eluents (Table I). The effluent was collected in 25-ml fractions and was titrated with EDTA (disodium salt) 7. Elution constants, E, and volume ,. .I ,..,,. Awzl. Chim. Ada, 52 (1970) 393-396
SHORT
394
COMMUNICATIONS
distribution coefficients, IA, were calculated as beforea. The eluents found to be most suitable, were used in the subsequent separations.
On the basis of elution constants and volume distribution coefficients, the may be arranged in order of decreasing efficiency as follows: N&04= (NH&S04 = NaCl= NH&l = NaNOg c HCl c HNOa c HClO4 < CH&OONH4. Scj3aratiorzs by gradient ehtion. Ions such as zinc, beryllium, caesium, uranium, rubidium, cadmium, lead and mercury are much more weakly bound to Dowex SOWSrz than cobalt. It is thus possible to remove first the unwanted cations with I M
eluents
0.3373 0.632 2
1.Gzg HJSO.~
200
1.0 2.0
7.5 So 40
3 .o ‘I.0
I-INO:1
2.9G5 I.582
0.247 x.123
3.GGr 0.8906
250
101.5
12s 75 *5o 50
200 200 200
100.7 g8.9 X02.1
75 50
2.50
99.6
_T.o-‘\.o
150
100.8
o.G322 1.123
1.582 0.89oG
2.ckt.o
75
200-300
100.3
0.0322
1.582
200
35.0 9g.G 100.5
o.G322 1.123
1.582 0.89oG
0.4398 o.G322 1.123
2.274 1.582 0.89oG
o-3373 0.6322 1.123
2.9G5 1.582 0.89oG
200
75 so 100
0.5 I.0
75 50
2.0
0.5
125
1.0
;z
2.0-3.0
52
0.3373 0.6322
100.0
3.0-4.0
Anal. Chim. Ada,
2,965 1.582 0.8goG
r SJ
1.0
(NH&SO.t
0.3373 0.6322 1.123
101.8
1.0-2.0
a&so.&
200 200
2.0
N
r.Gzg
75 50
1.0
NH&I
102.3
3.0
‘I.0
NaNO:,
120
I ,582 0.8goG o&14 1
3.0 100.4
3.0
NaCI
1.123
250
‘}.O
FT.1
oh322
101.g
‘2.5
4.0
CH:,COON
ro2.G
175 ‘50
2.0
I.0
I-ICIO.~
43.5
2.905 I .582 Oh141
(1970)
393-396
225 150 22s 150 12.5
100.0
275 150 I25
101.8 101.0 100.9
x01.4
99.8
SHORT
COMMUNICATIONS
395
hydrochloric acid and then &lute cobalt wit11 4 M hydrochloric acid (Table II). With some cations, other eluents were preferable: for uranium, 0.5 M sulphuric acid; for mercury, 0.5 M nitric acid; and for lead, 0.5 M ammonium acetate solutions. In these cases cobalt was removed later with the same eluent at a concentration of 4M.
Selective ehtiolz with ovgauic acids. Eluents such as oxalic. citric and tartaric acids in any concentrations are poor eluents for cobalt, but are good eluents for elements such as tin, iron, aluminium, manganese and antimony. Since z M ammonium sulphate has a high elution constant, it can be used to desorb cobalt from the column, after elution of other ions. Thus, 10% oxalic acid was used for the elution of tin, iron and aluminium, while 5% citric acid was used for antimony. It was possible to remove manganese with 10% tartaric acid. Cobalt, in all these cases, was subsequently eluted with z M ammonium sulphate. Selective elzttiort witlz specific eluents. Sodium chloride (I M) was found to be an efficient eluent for cobalt, but not for strontium, titanium, barium and magnesium ; cobalt could be first eluted with r M sodium chloride followed by the elution of strontium and magnesium with 4 M hydrochloric acid, or titanium and barium with 4-G M nitric acid. In the separation of copper from cobalt, copper could be first nluted with 0.5 M sulphuric acid followed by the elution of cobalt with 2 M ammonium sulphate. It was possible to effect separation of cobalt from nickel with 0.05 M EDTA, by taking advantage of the difference in pH; thus, cobalt was eluted with 0.05 M EDTA solution at PH 5.0, and then nickel with 0.05 M EDTA at pH 10.0. Cobalt could be separated from thallium by gradient elution by eluting first cobalt with 2 M sulphuric acid, followed by the elution of thallium with 4 M sulphuric acid. Separation of silver from cobalt was possible by first eluting silver with 2OA, sodium nitrite, and then cobalt with z M ammonium sulphate. TABLE
IL
ION-EXCHANGE
(CObiLlt
talccn
Foreigrb io?r
SEPARATION
=
25.335
An~ocr~rl added
OF
COt3hLT(II)
Wig) Cobalt
Anaottrrt added
Foreign iO?Z
Found
l?ecovared
(W)
(%I
26.2
50.8
25.3 25.4 25.4
Bi Th :It
Sr
51.5 SO.2 25.6 25.2 26.4 76.7 x4.G 75.8
25.3 25.1 25.0 25.0 25.1 25.3 25.0 25.0
100.0 100.4 roo.l# 100.0 99.8 99.6 99.6 99.8 100.0 99.6 99.6
Ti w!
10.0 52.4
25.3 25.4
100.0 100.4
rh20Ja-
Srl(I1) Ni
24.3 24*5
25.0 25.1
99.6 99.8
(W) Zn Be Cs lib Cd Ba
Cu(II) U(VL)a Tl(1) Pba
n
267
(mg) -p_
Zr(IV) Fc(lII) Al Mll(II) H&I 1)” Cr0d2VO.t-
25.2 12.8
25.8 102.3 2G.4 25.0 26.
I
Cobalt -. Found
Recovered
Iw’)
(%I
25.0 25.1 25.4 25.3 25.4 25.1 25.1
99.6 99.8 TOO.4 100.0 100.‘~
99.8 99.8
27.3 2G.g 52.3 43.8
25.0
25.4 25.3 25.4
100.4 100.0
49.7
W042-
25.G
25.1
25.3
99.8 100.0
Mo,Ozsl~-
26.5
25.0
99.6
99.6
100.,+
see text. A?tal.
CJkm. A&a,
52
(1970)
3gp-396
.~C/~tlY(l/I’flll
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01' IllOl\~lJtl~lt~'
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ztnionic.
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Il1isturcts
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