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Organic acid solutions in the chromatography of inorganic ions—IV
594
SHORT
0 I M tartarlc ocldpH=3.50
COMMUNICATIONS
0 I M tartarlc pH=400
P
cum
acid
0.2 M tartam acid pH= 3 50
0.2Mtartarlc acldpH=4.00
Ni (II)
ml of eluate
Fig. 1. Elutlon
curves of Fe(III), Cu(II), Ni(II), Co(II), Cd(I1) and Mn(I1) m tartaric 50 W X8 (2OS400 mesh), NH; form
EXPERIMENTAL
In the present work we describe the cation-exchange of the ions Mn(II), Cd(II), Co(II), P&(11), Cu(II), Al(II1) and Fe(III), m tartarlc acid solution at molarGies between 0.1 and 1.0 and at pH values up to 10. Table
1. K, values
on Dowex
50W X8 resm (20&400
acid. Resm Dowex
The resin used was Dowex 5OW X8, 20@400 mesh. It was converted into the NH:-form with 3M ammonium chloride and washed with demineralized water. For the
mesh),
NH:
form
in tartaric
acid at various
molarltles
and
PH K,, in tartarlc Tartaric acid concn., Ion
M
Mn(I1)
0.1 0.2 0.3 0.5 1.0 0.1 0.2 0.3 0.5
Cd(I1)
1.o Co(II)
Ni(I1)
Al(II1)
Cu(I1)
Fe(III)
0.1 02 0.3 0.5 1.0 01 0.2 0.3 0.5 1.0 01 0.2 0.3 0.5 10 0.1 0.2 0.3 0.5 1.0 0.1 0.2 0.3 05 1.0
the free acid* s.a. s.a. 4826 4326 4326 s.a. s.a s.a. s.a. s a. s a. s.a s.a. s.a. 2136 s.a. 4631 3282 2860 2860 s.a. s.a. s.a. s.a. s a. 3143 2493 1806 490 329 1324 1273 465 211 164
acid at DH values of
3 00
3.25
3.50
4.00
1423 299 129 41
782 165 51 21
339 73 30
135 24 8.2
8.00 74 14 1.3 OX.
9.00 OX.
OX
OX.
OX.
OX.
OX.
OX
OX.
209x4 102 58 28 13 18 n.a n.a. n.a. n.a. 94 48 34 21 14 n.a. n.a. na n a. n a. 142 88 51 39 4.1 n.a. n.a. n.a. n.a. n.a.
656 237 119 51 22 154 152 109 121 102 505 256 122 70 25 na n.a. na. n.a n.a. 452 444 189 17 5.9 na na. n.a. n.a. n.a.
OX
931 183 108 33
725 120 23 17
260 42 21
87 10.1 17
710 115 36 2.6
323 58 22 n.a.
128 6.6 n a.
32 n a. n.a.
520 67 8.9 n.a.
247 30 5.0 n.a.
12 n.a. n.a.
8.3 n.a. n.a.
443 51 n.a. n.a.
183 n.a. na. n a.
33 n.a n.a
3.1 n.a n.a.
96 n.a. n.a. n.a.
18 n.a. n.a. n.a.
7.7 n.a. n.a.
n a. n.a. n.a.
n.a. n.a. n.a. n.a.
n.a. n.a. n.a. n.a.
n.a. n.a. n.a.
n a. n.a n.a. -
* pH values for tartarlc acid of a given molarity are. O.lM, pH 2.10; 0.2M.pH l.OM. pH 1.50. n a. not adsorbed; s.a strongly adsorbed, ox. oxides.
45 16 6.0 4.6 2.5 19 n.a. n.a. n.a n.a. 76 0.9 na. na. n.a n.a. n.a. n.a. n.a. n.a. 6.4 6.1 71 5.6 4.1 n.a na. n a. n.a. n.a.
1.90; 0.3M.pH
1000
OX.
1.80; 0.5M,pH
1 70,
SHORT
COMMUNICATIONS
batch experiments the resin was air-dried to constant weight at 70” and stored in a desiccator over silica gel. The metal ions examined were used as 0.2N solutions of the chloride or nitrate salts, after standardization. Eluents The eluents were prepared from reagent grade chemicals. Tartaric acid was used at molarities of 0.1, 0.2, 0.3, 0.5 and 1.0. The pH was adjusted between 3.00 and 10.00 by the addition of ammonia or sodium hydroxide solution. Solid sodium hydroxide was used for the pH values 3.00, 3.25, 3.50 and 4.00 to avoid the precipitation of ammonium salts. For the pH values 8.00, 9.00 and 10.00, adjusted with cont. ammonia solution, increasing K,, values were obtained, while the uptake of the ions was zero from solutions adjusted with sodium hydroxide. Determination of K, values The distribution coefficients (Kd) were determined by the batch equilibration method. Resin (0.5 g dry weight), 50 ml of the appropriate tartaric acid solution and 2 ml of the metal Ion solution, were shaken for 15 hr at room temperature. After equilibration, the resin phase was separated by filtration and the ion concentration was determined on an aliquot of the filtrate, by atomic-absorption spectrophotometry, using the standard addition method. Columns For column experiments borosilicate glass tubes were used, 1.2 cm i.d., 28 cm long, fitted with sintered glass plates. The resin bed was 22 cm deep. Fractions (10 ml) were collected automatically and analysed by atomicabsorption spectrophotometry. RESULTS
AND
DISCUSSION
Table 1 gives the distribution coefficients (Kd) obtained m the present work. In tartaric acid the K, values decrease regularly with increase in the acid concentration. All the values are too high, however, to allow separations to be achieved m a short time with practical elution volumes. The K, values decrease with increasing tartrate concentration at constant pH and with rising pH at constant tartrate concentration. The value for Fe(III) differs markedly from that reported by Qureshi.“’ The K, values are in accord with the tendency of the ions to form tartrate complexes. ‘* When amonia is used to adjust the pH, there is a regular decrease of K, with increasing tartrate concentratlon at constant pH, and a regular increase of K, at constant tartrate concentration with increasing pH, with the exception of Mn(I1) which oxidizes, and Fe(II1) and
Al(III), can be plexes. From several
595
which are not absorbed. The increase of Kd values ascribed to the formation of cationic ammine comTable 1 we can predict interesting separations.
the possibdity
of achlevmg
Separation Fe(III), Cu(II), Ni(II), Co(II), Cd(I1) and Mn(I1) were separated. The resm was preconditioned with five bedvolumes of the first eluent and samples were added in the same medium (O.lM tartaric acid at pH 3.5). The elutlons were effected at an overpressure of 190 mmHg and the loading of the resin bed was 0.1 meq of each ion used. The flow-rate was 2.5 ml/min. Elution curves are shown in Fig. 1 and it can be seen that the peaks are sharp and well separated. Acknowledgements-The authors are grateful to Prof. R. Ferro, Director of the Institute, for his valuable interest and encouragement in this work and also to C.N.R. of Italy for financial support.
REFERENCES
1. R. Frache, A. Dadone and F. Baffi, 1/II Convegno Nazionale di Chimica Inorganica, Pesaro, Italy, 1974, Corn. DlO. 2. Idem, Atti de/ XII Congress0 Nazionale Societci Chimica Italiana, S. Margherita di Pula, Cagharl, Italy, 1975, Corn. CA5. 3. G. F. Pitstick, T. R. Sweet and G. P. Morie, Anal. Chem., 1963, 35, 995. 4. G. P. Merle and T. R. Sweet, ibid., 1964, 36, 140. 5. Idem, J. Chromatog., 1964, 16, 210. 6. K. Kimura, N. Saito, H. Kakiana and T. Ishimori, Nippon 985tif: Kaaaku Zasshi. 1953. 74. 305: Chem. Abstr.. 1953. b7, 7. D. I. Ryabchikov and V. E. Bukhtiarov, Zh. Anaht. Khim., 1952, 7, 377; Chem. Abstr., 1953, 47, 4787e. 8. A. P. Kreshkov and E. N. Sayushkina, Chem. Abstr., 1957, 51, 16197a. 9. Z. Marczenko, Chem. Anal. (Warsaw), 1957, 2, 255; Chem. Abstr., 1958, 52, 18545 10. M. Qureshi, K. G. Varshney and R. C. Kaushik, Anal. Chem., 1973, 45, 2433. 11. J. C. Rouchaud and G. Revel, J. Radioanal. Chem., 1973, 16, 221. 12. A. E. Martell and L. G. Sill& Stability Constants of Metal Zen Complexes, Suppl. No 1, p. 317. The Chemlcal Society, London, 1971
Summary-The cation-exchange behaviour of Mn(II), Cd(II), Co(II), Ni(II), Cu(II), Al(II1) and Fe(III), m tartaric acid media was studied. Separations of Fe(III), Cu(II), Ni(II), Co(II), Cd(I1) and Mn(I1) on Dowex 50W X8 have been achieved.
SHORT
0 I M tartarlc ocldpH=3.50
COMMUNICATIONS
0 I M tartarlc pH=400
P
cum
acid
0.2 M tartam acid pH= 3 50
0.2Mtartarlc acldpH=4.00
Ni (II)
ml of eluate
Fig. 1. Elutlon
curves of Fe(III), Cu(II), Ni(II), Co(II), Cd(I1) and Mn(I1) m tartaric 50 W X8 (2OS400 mesh), NH; form
EXPERIMENTAL
In the present work we describe the cation-exchange of the ions Mn(II), Cd(II), Co(II), P&(11), Cu(II), Al(II1) and Fe(III), m tartarlc acid solution at molarGies between 0.1 and 1.0 and at pH values up to 10. Table
1. K, values
on Dowex
50W X8 resm (20&400
acid. Resm Dowex
The resin used was Dowex 5OW X8, 20@400 mesh. It was converted into the NH:-form with 3M ammonium chloride and washed with demineralized water. For the
mesh),
NH:
form
in tartaric
acid at various
molarltles
and
PH K,, in tartarlc Tartaric acid concn., Ion
M
Mn(I1)
0.1 0.2 0.3 0.5 1.0 0.1 0.2 0.3 0.5
Cd(I1)
1.o Co(II)
Ni(I1)
Al(II1)
Cu(I1)
Fe(III)
0.1 02 0.3 0.5 1.0 01 0.2 0.3 0.5 1.0 01 0.2 0.3 0.5 10 0.1 0.2 0.3 0.5 1.0 0.1 0.2 0.3 05 1.0
the free acid* s.a. s.a. 4826 4326 4326 s.a. s.a s.a. s.a. s a. s a. s.a s.a. s.a. 2136 s.a. 4631 3282 2860 2860 s.a. s.a. s.a. s.a. s a. 3143 2493 1806 490 329 1324 1273 465 211 164
acid at DH values of
3 00
3.25
3.50
4.00
1423 299 129 41
782 165 51 21
339 73 30
135 24 8.2
8.00 74 14 1.3 OX.
9.00 OX.
OX
OX.
OX.
OX.
OX.
OX
OX.
209x4 102 58 28 13 18 n.a n.a. n.a. n.a. 94 48 34 21 14 n.a. n.a. na n a. n a. 142 88 51 39 4.1 n.a. n.a. n.a. n.a. n.a.
656 237 119 51 22 154 152 109 121 102 505 256 122 70 25 na n.a. na. n.a n.a. 452 444 189 17 5.9 na na. n.a. n.a. n.a.
OX
931 183 108 33
725 120 23 17
260 42 21
87 10.1 17
710 115 36 2.6
323 58 22 n.a.
128 6.6 n a.
32 n a. n.a.
520 67 8.9 n.a.
247 30 5.0 n.a.
12 n.a. n.a.
8.3 n.a. n.a.
443 51 n.a. n.a.
183 n.a. na. n a.
33 n.a n.a
3.1 n.a n.a.
96 n.a. n.a. n.a.
18 n.a. n.a. n.a.
7.7 n.a. n.a.
n a. n.a. n.a.
n.a. n.a. n.a. n.a.
n.a. n.a. n.a. n.a.
n.a. n.a. n.a.
n a. n.a n.a. -
* pH values for tartarlc acid of a given molarity are. O.lM, pH 2.10; 0.2M.pH l.OM. pH 1.50. n a. not adsorbed; s.a strongly adsorbed, ox. oxides.
45 16 6.0 4.6 2.5 19 n.a. n.a. n.a n.a. 76 0.9 na. na. n.a n.a. n.a. n.a. n.a. n.a. 6.4 6.1 71 5.6 4.1 n.a na. n a. n.a. n.a.
1.90; 0.3M.pH
1000
OX.
1.80; 0.5M,pH
1 70,
SHORT
COMMUNICATIONS
batch experiments the resin was air-dried to constant weight at 70” and stored in a desiccator over silica gel. The metal ions examined were used as 0.2N solutions of the chloride or nitrate salts, after standardization. Eluents The eluents were prepared from reagent grade chemicals. Tartaric acid was used at molarities of 0.1, 0.2, 0.3, 0.5 and 1.0. The pH was adjusted between 3.00 and 10.00 by the addition of ammonia or sodium hydroxide solution. Solid sodium hydroxide was used for the pH values 3.00, 3.25, 3.50 and 4.00 to avoid the precipitation of ammonium salts. For the pH values 8.00, 9.00 and 10.00, adjusted with cont. ammonia solution, increasing K,, values were obtained, while the uptake of the ions was zero from solutions adjusted with sodium hydroxide. Determination of K, values The distribution coefficients (Kd) were determined by the batch equilibration method. Resin (0.5 g dry weight), 50 ml of the appropriate tartaric acid solution and 2 ml of the metal Ion solution, were shaken for 15 hr at room temperature. After equilibration, the resin phase was separated by filtration and the ion concentration was determined on an aliquot of the filtrate, by atomic-absorption spectrophotometry, using the standard addition method. Columns For column experiments borosilicate glass tubes were used, 1.2 cm i.d., 28 cm long, fitted with sintered glass plates. The resin bed was 22 cm deep. Fractions (10 ml) were collected automatically and analysed by atomicabsorption spectrophotometry. RESULTS
AND
DISCUSSION
Table 1 gives the distribution coefficients (Kd) obtained m the present work. In tartaric acid the K, values decrease regularly with increase in the acid concentration. All the values are too high, however, to allow separations to be achieved m a short time with practical elution volumes. The K, values decrease with increasing tartrate concentration at constant pH and with rising pH at constant tartrate concentration. The value for Fe(III) differs markedly from that reported by Qureshi.“’ The K, values are in accord with the tendency of the ions to form tartrate complexes. ‘* When amonia is used to adjust the pH, there is a regular decrease of K, with increasing tartrate concentratlon at constant pH, and a regular increase of K, at constant tartrate concentration with increasing pH, with the exception of Mn(I1) which oxidizes, and Fe(II1) and
Al(III), can be plexes. From several
595
which are not absorbed. The increase of Kd values ascribed to the formation of cationic ammine comTable 1 we can predict interesting separations.
the possibdity
of achlevmg
Separation Fe(III), Cu(II), Ni(II), Co(II), Cd(I1) and Mn(I1) were separated. The resm was preconditioned with five bedvolumes of the first eluent and samples were added in the same medium (O.lM tartaric acid at pH 3.5). The elutlons were effected at an overpressure of 190 mmHg and the loading of the resin bed was 0.1 meq of each ion used. The flow-rate was 2.5 ml/min. Elution curves are shown in Fig. 1 and it can be seen that the peaks are sharp and well separated. Acknowledgements-The authors are grateful to Prof. R. Ferro, Director of the Institute, for his valuable interest and encouragement in this work and also to C.N.R. of Italy for financial support.
REFERENCES
1. R. Frache, A. Dadone and F. Baffi, 1/II Convegno Nazionale di Chimica Inorganica, Pesaro, Italy, 1974, Corn. DlO. 2. Idem, Atti de/ XII Congress0 Nazionale Societci Chimica Italiana, S. Margherita di Pula, Cagharl, Italy, 1975, Corn. CA5. 3. G. F. Pitstick, T. R. Sweet and G. P. Morie, Anal. Chem., 1963, 35, 995. 4. G. P. Merle and T. R. Sweet, ibid., 1964, 36, 140. 5. Idem, J. Chromatog., 1964, 16, 210. 6. K. Kimura, N. Saito, H. Kakiana and T. Ishimori, Nippon 985tif: Kaaaku Zasshi. 1953. 74. 305: Chem. Abstr.. 1953. b7, 7. D. I. Ryabchikov and V. E. Bukhtiarov, Zh. Anaht. Khim., 1952, 7, 377; Chem. Abstr., 1953, 47, 4787e. 8. A. P. Kreshkov and E. N. Sayushkina, Chem. Abstr., 1957, 51, 16197a. 9. Z. Marczenko, Chem. Anal. (Warsaw), 1957, 2, 255; Chem. Abstr., 1958, 52, 18545 10. M. Qureshi, K. G. Varshney and R. C. Kaushik, Anal. Chem., 1973, 45, 2433. 11. J. C. Rouchaud and G. Revel, J. Radioanal. Chem., 1973, 16, 221. 12. A. E. Martell and L. G. Sill& Stability Constants of Metal Zen Complexes, Suppl. No 1, p. 317. The Chemlcal Society, London, 1971
Summary-The cation-exchange behaviour of Mn(II), Cd(II), Co(II), Ni(II), Cu(II), Al(II1) and Fe(III), m tartaric acid media was studied. Separations of Fe(III), Cu(II), Ni(II), Co(II), Cd(I1) and Mn(I1) on Dowex 50W X8 have been achieved.