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Internal electrolysis for the separation of ions.
ANALYTICA
SHORT
CHIMICA
ACTA
COMMUNICATIONS
Internal electrolysis for the separation of ions. Part II. Determination of antimony and lead in presence of other ions. Separation and determination of Ag, Bi, Cu, Pb, Cd and Sb fn a previous paper1 the separation and determination of copper, cadmmm, srlver and brsmuth by means of mtemal electrolysis with a zinc anode through suitable PH control and ad&Lion of complexmg agents, were described In further work on this very sample technique. it was shown that the method can be used for the determination of lead and antimony In presence of other ions, and for the separation and determmatlon of copper, cadmium, silver, bismuth, antimony and lead from each other by control of the experlmcntal conditions. Apparatus md solutrons A Cambndge PH m&cator and the apparatus assembly conslstmg of a platinum gauze cathode and a zmc plate anode were the same as used earllerl A copper plate, m place of zinc, as anode was used only when sllvcr was to be separated from bismuth The chenucals used were of hlghcst punty. Antrmony sohtton. This was prepared by drssolvmg antimony trrchlonde m water contauung sufficient hydrochloric acid to prevent hydrolysis, and was standardized lodlmetrlcally~. Lerrdsofutzo:r This was prepared from lead nitrate m water wrth the addition of a httle nitric acid, and was standardized by titration with EDTA3 Standard solutions of copper, caclrmum, bismuth and silver and of other cations and anions as well as IO”/-, solutions of complexmg agents such as sodium potassmm tartrate, EDTA (d.rsodium salt) and potassmrn cyanide were the same as reported previously1 Gentval procedrrre
The metal ion to be deposited mised with the other ions, each 5-10 times the quantity of the deposltable ion, was taken m a tall beaker. When an mterfenng Ion was studred, an amount of this ion so-IOO tunes greater than that of the ion to be deposited was taken For the separation and determmalon of lead, tartrate and cyanide, each at least IO times the total weight of the ions present, were added to the solution and then after dilution to 25-300 ml or to any requned volume to keep the Ions and complexmg agents m solution, the pH was adjusted to g.o-Io o. For the determmation of antimony in presence of other Ions an amount of EDTA, IO times the waght of the ions to be complexed, was added before the solution was diluted as stated above and adJusted to pH 8 5-g 5 The Pt-Zn electrode assembly with previously weighed platmum gauze cathode was then placedin either of the solutions After the time necessary for deposition, the apparatus assembly was removed and washed with water over the solution The Arraf
Cl~arn Acta.
36 (1966)
3gg-.pz
SHORT COMMUNICATIONS
400
cathode was then disconnected from the anode, washed again with alcohol, dried at 8o”-goo and weighed as described previouslyl. Before further use, the platinum cathode was cleaned with acid to remove any previous deposit, washed with water and alcohol, heated to redness over a nonluminous flame, cooled in a desiccator and weighed. and se$aration of lead At PH g-10 in the presence of tartrate and cyanide, lead was completely deposited as the metal on the platinum cathode and thus determined after separation from I;e, Al, Cr, Ti, Th, Zr, Be, Zn, Mn, Ni, Co, W, V, La, In, TI(I), Ta and alkali and alkaline earth metals. Results are shown in Table I. For the determination of co$$er and lead, the solution containing both ions was treated with a ro-fold weight of EDTA, diluted to 250 ml and adjusted to PH 9.0. Copper was first deposited completely in 24 11,washed, dried and weighed as described in the Geneva2 @ocedzcre; then lead was deposited from the residual solution at PH 2.5, washed, dried, etc. Results are given in Table II.
Determination
TABLH
I
TABLE
DETRRMINATION OIr LRAD l’ROM
(Deposition PH
9.0 9.5 9.0 10.0 9.0
10.0
TABLE
AND OTHER
SUPARATION IONS
Ctt
time 6.0 II)
Pb taken (Wj
fouud Cwl
2.64 2.G4 1.32 3.9’5 3.96 x.32
2.64
a&3 I.32 3.95 3.93 I-33
OF
BISMUTH
AND
Idten (w.l
fourrd (WJ
2.14
2.1 I
2.04
X.07
I .05
3.96
2.64 3.95 1.31 --
3.20
1.32
IV
(Deposition fiH
ni takew (w)
l’b found (wj
t&en Owl
found
0.96’ I.93
0.94 I.92
2.64 x.32
cms) 2.G2 1.32
2.8g
2.87
3-96
3.95
LRAD
la/rcn (ml
TABLE
OF SILVER,
AND
P1
DETERMINATION OF ANTIMONY D&TERMINATION
COPPER
.found f wl
3.21
III
SIMULTANEOUS LEAD
II
DRTERMINATION --
AND SEPARATION FROM OTHRR IONS
time 1.5 h)
Sb taken (w)
found Owl
2.50 I.25
2.48
::z 9.0
2.50 3.75
2.50 3.73
9.0
3.75
3.72
I.25
When lead and cadmium are present in a mixture, the metals can be deposited successively in the presence of LEDTA by simple PH adjustmentl. ‘For the determination of lead, siher and bismuth, EDTA and potassium cyanide (each IO times the weight of the total ions) were added to the solution which was then diluted to 250 ml and adjusted to PH 9.0. Both silver and bismuth were complet?ly deposited within 12 h, washed, dried and weighed. These metals were then :, “. ;Qnal. CA&. .’
Acta, 36
(x966) 399-402
O-’
SHORT
4or
COMMUNICATIONS
separately deposited in about 6 h each, silver with a copper anode and bismuth with the zinc anodel. The main residual solution was then evaporated to 250 ml and an excess of formaldehyde was added. Lead was then deposited at PH 2.5, washed, etc., in the usual way. Results are shown in Table III.
Determination
and separation
of antimony
With EDTA as the complexing agent and at PH 8.5-9.5, antimony was quantitatively deposited as the metal and thus separated from Be, Zn, Mn, Co, Ni, Sn(IV), Al, La, Cr, Ga, In, n(I), Zr, Th, Te(lV), Nb, Ta, V, W, U(VI), Cd, Pb, As(V), Ti and alkali and alkaline earth metals. Typical results are shown in Table IV. Iron(Il1) in amounts about IO times that of antimony prevented the deposition of the latter in the presence of EDTA and cyanide in the PH range 2.5-10, but had no effect at PH 0.5-1.0; more than 1000 mg of iron(II.1) could be tolerated in the deposition of 1.25-2.50 mg Sb in the latter range with deposition times of 3 h. This effect of iron(II1) was fully utilized in the separation of antimony from bismuth or silver and from lead or cadmium. For the determination of antimony, bismuth and silver, iron(III) (at least IO times the weight of antimony present) was added followed by EDTA and potassium cyanide (each IO times the total weight of the metal ions). The solution was then diluted to 250 ml and the PH adjusted to 8.5-9.0. Both silver and bismuth were then TABLIZ V DDTICRhfINATION
OF ANTIMONY,
RISMUTH
AND
STLVHR
Bi
taken f WT)
.
1.0 2.0
3.0
I.0
I.99 2.97
2.89 I.93 0.96
2.86 I.93 0.94
1.25
2.5 3.75
1.25 2.48 3.72
deposited and finally determined as described previously’. An excess of formaldehyde was then added to the residual solution and the pH adjusted to 1.0; antimony was then deposited completely in 3 h. Results are given in Table V. For separation from copper, EDTA and an excess of cyanide were added before deposition of antimony at PH 8.595; copper was then deposited after cyanide had been’ masked with formaldehyde. However, if the solution also contained iron(III), simple pH control in presence of EDTA allowed successive deposition of copper and antimony. Ten-fold weights of iron(II1) and EDT’A were added as indicated for the Sb-Bi-Ag separation and then copper was deposited at PH 9.0 and antimony at pH 1.0. Results are shown in Table VI. For the determination of antimony, lead and cadmium, iron(rI1) and EDTA were added as in the Cu-Sb method. Lead was then deposited at pH 2.5, cadmium at pH 4.0 and finally antimony at PH 1.0, the volume of solution being maintained at 250 ml. Cadmium deposited completely in 12 h. Results are shown in Table VII.
Determination
of Ag, Bi, Cu, Cd, Pb and Sb
In this case, iron(III),
EDTA
and cyanide were added zs in the Ag-Bi-Sb Anal. Ckim. Acta,
36 (1966)
399-402
SHORT CO~IMUNICATIONS
402 TABLE
I
VI
DETERMINATIONOF
COPPER
AND
ANTIMONY
Sb
CZL taken (m&
Jound (ms)
taken (mc)
fowd (ml)
2.14 3.21
2.12 9’::
2.5 I.25
2.46 1.24
3.75
3.72
1.07
.
TABLE
VII
SEPARATION
OP
LEAD,CADMIUM
AND
ANTIMONY
Cd
Pb
Sb
tdken (m6)
Jound (msl
take78 (ms)
1.32 2.G4 3.96 -_
1.32 2.G3 3.93
2.Gt.5
TABLE
found f mgl
2.64 I.33 I.33 3.99 3.96 __-___----
taken (msl
found f wl
2.5 3.75 I.25
2.47 3.73 I.25
WT.1
SI~PARATION
OF
Ag,
Bi, Cu, Pb,Cd
AND
Sb
Total deposit (tng)
Taken (tns) 4
ni
czc
Pb
CO?
Sb
Agf
2.0 I.0
I.93 I.93
2.1.)
2.0
0.96
2.64 1.32 3.96
2.6G I.33 = *33
2.50 2.50 3.75
3.90 2.95 2.97
I.07 3.21
Bi
Found Ag
--
(nrg)
Bi
Czr
PI,
Cd 2.6s
x.97
1.92
2.I4
1.93
1.07
2.63
1.00
I.98
0.96
3.19
3-94
1.30 --
Sb 2.47
1.32
2.50
r-33
3.74
method; the volume was then adjusted to 250-300 ml and the pH to 9.0. Silver and bismuth were then deposited over a period of 12 h. After being washed, this deposit was dissolved in dilute nitric acid and silver and bismuth were separately depositedl. The residual solution containing Cu. Cd, Pb and Sb was concentrated and an excess of formaldehyde added. Copper was then deposited at PH 9.0, and lead, cadmium and antimony were deposited at PH values of 2.5; 4.0 and i.ii respectively. For all these depositions, the volume of the solution was maintained at 250-300 ml and each time the same Pt-Zn assembly was used, the cathode being freshly cleaned and weighed between determinations. Thus by the simple control of pH, Cu, Cd, Pb and Sb were determined one by orie in the same solution, Typical results are shown in Table VIII. DepartmeM of Inorganic and Analytical Chemistry, Jadavjhw University Calcutta-32 (India) I A. I<. MAJUMDAR 2 A. I. VOGEL, A
A. I<. MAJUMDAR SM. GOURI BHOWAL .
AND SW. GOURI BHOWAL, Anal. Ckim. Acta. 35 (x966) 206. Text Book of Quantitative A?ralysis including Blementary Instrwaental Attalysis. 3rd Edn., Longmans Green, London, xgGa. 3 H. FLASIIKA, EDTA Titvnfioas. A71 I7rtroductiort to tks Theory and Practice, Pcrgarkn Press, London, r959.
(Received Anal.
March
Chim. Acta,
x8th, rgG6) 36 (x966) 399-402
SHORT
CHIMICA
ACTA
COMMUNICATIONS
Internal electrolysis for the separation of ions. Part II. Determination of antimony and lead in presence of other ions. Separation and determination of Ag, Bi, Cu, Pb, Cd and Sb fn a previous paper1 the separation and determination of copper, cadmmm, srlver and brsmuth by means of mtemal electrolysis with a zinc anode through suitable PH control and ad&Lion of complexmg agents, were described In further work on this very sample technique. it was shown that the method can be used for the determination of lead and antimony In presence of other ions, and for the separation and determmatlon of copper, cadmium, silver, bismuth, antimony and lead from each other by control of the experlmcntal conditions. Apparatus md solutrons A Cambndge PH m&cator and the apparatus assembly conslstmg of a platinum gauze cathode and a zmc plate anode were the same as used earllerl A copper plate, m place of zinc, as anode was used only when sllvcr was to be separated from bismuth The chenucals used were of hlghcst punty. Antrmony sohtton. This was prepared by drssolvmg antimony trrchlonde m water contauung sufficient hydrochloric acid to prevent hydrolysis, and was standardized lodlmetrlcally~. Lerrdsofutzo:r This was prepared from lead nitrate m water wrth the addition of a httle nitric acid, and was standardized by titration with EDTA3 Standard solutions of copper, caclrmum, bismuth and silver and of other cations and anions as well as IO”/-, solutions of complexmg agents such as sodium potassmm tartrate, EDTA (d.rsodium salt) and potassmrn cyanide were the same as reported previously1 Gentval procedrrre
The metal ion to be deposited mised with the other ions, each 5-10 times the quantity of the deposltable ion, was taken m a tall beaker. When an mterfenng Ion was studred, an amount of this ion so-IOO tunes greater than that of the ion to be deposited was taken For the separation and determmalon of lead, tartrate and cyanide, each at least IO times the total weight of the ions present, were added to the solution and then after dilution to 25-300 ml or to any requned volume to keep the Ions and complexmg agents m solution, the pH was adjusted to g.o-Io o. For the determmation of antimony in presence of other Ions an amount of EDTA, IO times the waght of the ions to be complexed, was added before the solution was diluted as stated above and adJusted to pH 8 5-g 5 The Pt-Zn electrode assembly with previously weighed platmum gauze cathode was then placedin either of the solutions After the time necessary for deposition, the apparatus assembly was removed and washed with water over the solution The Arraf
Cl~arn Acta.
36 (1966)
3gg-.pz
SHORT COMMUNICATIONS
400
cathode was then disconnected from the anode, washed again with alcohol, dried at 8o”-goo and weighed as described previouslyl. Before further use, the platinum cathode was cleaned with acid to remove any previous deposit, washed with water and alcohol, heated to redness over a nonluminous flame, cooled in a desiccator and weighed. and se$aration of lead At PH g-10 in the presence of tartrate and cyanide, lead was completely deposited as the metal on the platinum cathode and thus determined after separation from I;e, Al, Cr, Ti, Th, Zr, Be, Zn, Mn, Ni, Co, W, V, La, In, TI(I), Ta and alkali and alkaline earth metals. Results are shown in Table I. For the determination of co$$er and lead, the solution containing both ions was treated with a ro-fold weight of EDTA, diluted to 250 ml and adjusted to PH 9.0. Copper was first deposited completely in 24 11,washed, dried and weighed as described in the Geneva2 @ocedzcre; then lead was deposited from the residual solution at PH 2.5, washed, dried, etc. Results are given in Table II.
Determination
TABLH
I
TABLE
DETRRMINATION OIr LRAD l’ROM
(Deposition PH
9.0 9.5 9.0 10.0 9.0
10.0
TABLE
AND OTHER
SUPARATION IONS
Ctt
time 6.0 II)
Pb taken (Wj
fouud Cwl
2.64 2.G4 1.32 3.9’5 3.96 x.32
2.64
a&3 I.32 3.95 3.93 I-33
OF
BISMUTH
AND
Idten (w.l
fourrd (WJ
2.14
2.1 I
2.04
X.07
I .05
3.96
2.64 3.95 1.31 --
3.20
1.32
IV
(Deposition fiH
ni takew (w)
l’b found (wj
t&en Owl
found
0.96’ I.93
0.94 I.92
2.64 x.32
cms) 2.G2 1.32
2.8g
2.87
3-96
3.95
LRAD
la/rcn (ml
TABLE
OF SILVER,
AND
P1
DETERMINATION OF ANTIMONY D&TERMINATION
COPPER
.found f wl
3.21
III
SIMULTANEOUS LEAD
II
DRTERMINATION --
AND SEPARATION FROM OTHRR IONS
time 1.5 h)
Sb taken (w)
found Owl
2.50 I.25
2.48
::z 9.0
2.50 3.75
2.50 3.73
9.0
3.75
3.72
I.25
When lead and cadmium are present in a mixture, the metals can be deposited successively in the presence of LEDTA by simple PH adjustmentl. ‘For the determination of lead, siher and bismuth, EDTA and potassium cyanide (each IO times the weight of the total ions) were added to the solution which was then diluted to 250 ml and adjusted to PH 9.0. Both silver and bismuth were complet?ly deposited within 12 h, washed, dried and weighed. These metals were then :, “. ;Qnal. CA&. .’
Acta, 36
(x966) 399-402
O-’
SHORT
4or
COMMUNICATIONS
separately deposited in about 6 h each, silver with a copper anode and bismuth with the zinc anodel. The main residual solution was then evaporated to 250 ml and an excess of formaldehyde was added. Lead was then deposited at PH 2.5, washed, etc., in the usual way. Results are shown in Table III.
Determination
and separation
of antimony
With EDTA as the complexing agent and at PH 8.5-9.5, antimony was quantitatively deposited as the metal and thus separated from Be, Zn, Mn, Co, Ni, Sn(IV), Al, La, Cr, Ga, In, n(I), Zr, Th, Te(lV), Nb, Ta, V, W, U(VI), Cd, Pb, As(V), Ti and alkali and alkaline earth metals. Typical results are shown in Table IV. Iron(Il1) in amounts about IO times that of antimony prevented the deposition of the latter in the presence of EDTA and cyanide in the PH range 2.5-10, but had no effect at PH 0.5-1.0; more than 1000 mg of iron(II.1) could be tolerated in the deposition of 1.25-2.50 mg Sb in the latter range with deposition times of 3 h. This effect of iron(II1) was fully utilized in the separation of antimony from bismuth or silver and from lead or cadmium. For the determination of antimony, bismuth and silver, iron(III) (at least IO times the weight of antimony present) was added followed by EDTA and potassium cyanide (each IO times the total weight of the metal ions). The solution was then diluted to 250 ml and the PH adjusted to 8.5-9.0. Both silver and bismuth were then TABLIZ V DDTICRhfINATION
OF ANTIMONY,
RISMUTH
AND
STLVHR
Bi
taken f WT)
.
1.0 2.0
3.0
I.0
I.99 2.97
2.89 I.93 0.96
2.86 I.93 0.94
1.25
2.5 3.75
1.25 2.48 3.72
deposited and finally determined as described previously’. An excess of formaldehyde was then added to the residual solution and the pH adjusted to 1.0; antimony was then deposited completely in 3 h. Results are given in Table V. For separation from copper, EDTA and an excess of cyanide were added before deposition of antimony at PH 8.595; copper was then deposited after cyanide had been’ masked with formaldehyde. However, if the solution also contained iron(III), simple pH control in presence of EDTA allowed successive deposition of copper and antimony. Ten-fold weights of iron(II1) and EDT’A were added as indicated for the Sb-Bi-Ag separation and then copper was deposited at PH 9.0 and antimony at pH 1.0. Results are shown in Table VI. For the determination of antimony, lead and cadmium, iron(rI1) and EDTA were added as in the Cu-Sb method. Lead was then deposited at pH 2.5, cadmium at pH 4.0 and finally antimony at PH 1.0, the volume of solution being maintained at 250 ml. Cadmium deposited completely in 12 h. Results are shown in Table VII.
Determination
of Ag, Bi, Cu, Cd, Pb and Sb
In this case, iron(III),
EDTA
and cyanide were added zs in the Ag-Bi-Sb Anal. Ckim. Acta,
36 (1966)
399-402
SHORT CO~IMUNICATIONS
402 TABLE
I
VI
DETERMINATIONOF
COPPER
AND
ANTIMONY
Sb
CZL taken (m&
Jound (ms)
taken (mc)
fowd (ml)
2.14 3.21
2.12 9’::
2.5 I.25
2.46 1.24
3.75
3.72
1.07
.
TABLE
VII
SEPARATION
OP
LEAD,CADMIUM
AND
ANTIMONY
Cd
Pb
Sb
tdken (m6)
Jound (msl
take78 (ms)
1.32 2.G4 3.96 -_
1.32 2.G3 3.93
2.Gt.5
TABLE
found f mgl
2.64 I.33 I.33 3.99 3.96 __-___----
taken (msl
found f wl
2.5 3.75 I.25
2.47 3.73 I.25
WT.1
SI~PARATION
OF
Ag,
Bi, Cu, Pb,Cd
AND
Sb
Total deposit (tng)
Taken (tns) 4
ni
czc
Pb
CO?
Sb
Agf
2.0 I.0
I.93 I.93
2.1.)
2.0
0.96
2.64 1.32 3.96
2.6G I.33 = *33
2.50 2.50 3.75
3.90 2.95 2.97
I.07 3.21
Bi
Found Ag
--
(nrg)
Bi
Czr
PI,
Cd 2.6s
x.97
1.92
2.I4
1.93
1.07
2.63
1.00
I.98
0.96
3.19
3-94
1.30 --
Sb 2.47
1.32
2.50
r-33
3.74
method; the volume was then adjusted to 250-300 ml and the pH to 9.0. Silver and bismuth were then deposited over a period of 12 h. After being washed, this deposit was dissolved in dilute nitric acid and silver and bismuth were separately depositedl. The residual solution containing Cu. Cd, Pb and Sb was concentrated and an excess of formaldehyde added. Copper was then deposited at PH 9.0, and lead, cadmium and antimony were deposited at PH values of 2.5; 4.0 and i.ii respectively. For all these depositions, the volume of the solution was maintained at 250-300 ml and each time the same Pt-Zn assembly was used, the cathode being freshly cleaned and weighed between determinations. Thus by the simple control of pH, Cu, Cd, Pb and Sb were determined one by orie in the same solution, Typical results are shown in Table VIII. DepartmeM of Inorganic and Analytical Chemistry, Jadavjhw University Calcutta-32 (India) I A. I<. MAJUMDAR 2 A. I. VOGEL, A
A. I<. MAJUMDAR SM. GOURI BHOWAL .
AND SW. GOURI BHOWAL, Anal. Ckim. Acta. 35 (x966) 206. Text Book of Quantitative A?ralysis including Blementary Instrwaental Attalysis. 3rd Edn., Longmans Green, London, xgGa. 3 H. FLASIIKA, EDTA Titvnfioas. A71 I7rtroductiort to tks Theory and Practice, Pcrgarkn Press, London, r959.
(Received Anal.
March
Chim. Acta,
x8th, rgG6) 36 (x966) 399-402