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Exchange properties of ammonium salts of 12-heteropolyacids—V. Sorption of alkali metals on ammonium phosphomolybdatotungstate
J. Inorg.Nucl. Chem., 1963, Vol. 25. pp. 1191 to 1199. PergamonPress Ltd. Printedin Northern Ireland
NOTES
Exchange properties of ammonium salts of 12-heteropolyacids--V. Sorption of alkali metals on ammonium phosphomolybdatotungstate (Received 17 December 1962; in revised form 3 March 1963) HETEROPOLYAC1DShave been used for the precipitation of heavy alkali metalst~, ~ and their exchange properties have been described, t3,4~ Ammonium phosphomolybdate t4~ and ammonium phosphotungstate ~s~have been thoroughly investigated, and the present study describes the exchange properties of ammonium salts of phosphomolybdatotungstic acid (NH4PMoW) with various molar ratios of Mo:W. The uptake was studied under both static and dynamic conditions ~6~using acid ammonium salts of phosphomolybdatotungstic acids with varying molar ratios of M o : W (4:8, 6:6, 8:4). These were precipitated with an excess of 1 M NH4NO3 from aqueous solutions of the free heteropolyacids obtained by the etherate method ;t v~ analyses corresponded to the formula in Table 1. TABLE 1 Ion exchanger
Formula
Mol. Wt.
NH4PMo4Ws
(NH4)2,~sH0,4s[PMo4WaO~o]'6,5"H20
2666
NH4PMooWo
(NH4)z,6sHo,42 [PMosWsO~o]'7,6"H20
2510
NH~PMosW4
(NH4)~.48H0.52 [PMosW4040]" 5,7-H~O
2299
Figure 1 shows the uptake of Cs and Rb as a function of NH4 + ion concentration and demonstrates the ion-exchange nature of the process. Caesium is sorbed more easily than rubidium, in agreement with the values of the crystallographic radii, tsj Ka(Cs) decreases in the order NH4PMosW4 > NH4PMo6W~ > NH~PMo4Ws and from the measured Kd values for caesium and rubidium the theoretical value of the separation factor ~Rb cs was calculated to be 35 on NFI4PMo4Ws in 0.001 M HNO3. The effect of acidity on Ka at const. [NHa +] is practically negligible up to 2 M HNO3, but at higher acidity Ka decreases. ~a~ tll W. J. O'LEARY and J. PAP]SH, Ind. Eng. Chem. Anal. Edit. 6, 107 (1934). t~l M. H. FELDMANand L. E. GLENDENIN,l~. NES Part IV, 9, 654 (1951). tal H. BUCI~WALDand W. P. TmSTLE~-IWAITE,J. Inorg. Nucl. Chem. 5, 341 (1958). c4~j. VAN R. SM/T, J. J. JACOBSand W. ROBB, J. Inorg. NucL Chem. 12, 95 (1959). isJ j. K ~ L and V. KouklM, J. Inorg. NacL Chem. 12, 367 (1960). to~ j. KRTIL, Or. Inorff. Nacl. Chem. 19, 298 (1961). tT~A. I. KOKORINand N. A. POLOTEBNOVA,Zh. Obshch. Chim. 26, 1 (1956). ts) A. F. WELLS,Structural Inorganic Chemistry (2nd Ed.), Clarendon, Oxford (1950). ca~j. KRTIL, J. Inorg. NucL Chem. 24, 1139 (1962). 1191
1192
Notes
u~ 4
3
o.J
4
I
0
,
i
FIG. 1 . - - D e p e n d e n c e o f t h e d i s t r i b u t i o n coefficients Ka o n e q u i l i b r i u m c o n c e n t r a t i o n of ammonium ions in the solution. A , .. NH4PMo4W8
B . . . NI-I4PMo6We
C . . . NH4PMosW4
A--C indicates Cs
[ H +] = [0,001 M]
D ....
Kd ....
D ....
indicates Rb indicates NH~PMo4Ws
ml/g
CN,~No 3 , . m o l a r i t y o f N H ~ N O 3
Notes
1193
Dynamic experiments Microquantities of Cs and Rb were found to be sorbed in neutral media (0.4 M NaNO3) and also in strong acids (12 M HCI, 12 M HNO3). 1 M NH4NO3 elutes Rb quantitatively, and caesium can be eluted quantitatively with 10 M NH4NO3. Satisfactory results were also obtained with
Rb
C/Co
0
[
7OO
0
I 200
300
400 ,q
FIG. 2.~Separation of trace S~Rb from trace ~37Cs. Column: 1"13 cm ~ × 12cm, ion exchanger: NH4PMo4W8 b e d - - 3 cm, weight ratio NH4PMo4Ws: asbestos = 1:1, drop interval 15 sec. C/Ca . . . . volume per cent of alkali in I drop of eluate n...
number of drops
macro-amounts of Cs. Figure 2 shows the separation of traces of Rb from Cs on NH4PMo4Ws by elution with 1 M NH4NOa followed by 10 M NH4NO3.
Institute of Nuclear Research Chechoslovac Academy of Sc&nces Re~ u Prahy
J. KRTIL I. K~Iv,2
Spectrophotometric and potentiometric investigations on Mn (iii)-l:8 dihydroxy naphthalene 3:6 disulphonic acid chelate (Received 29 April 1963) IN RECENTyears the complexes of 1 : 8 dihydroxy naphthalene 3 : 6 disulphonic acid (chromotropic acid) have received considerable attention since many of them find uses in analytical chemistry. SCHWARZEr'raACH~1~made a detailed study of the Fe(iii) chelate while SOMra~R~ and coworkers carried out an extensive study of the Ti(iv) complexes and they have been used for the colorimetric estimation of Ti(iv). WARE~3~suggested the use of this reagent for the determination of uranium. Little has been done on the interaction of unstable oxidation states with chromotropic acid. In the present communication the results of the interaction of chromotropic acid with Mn(iii) described employing spectrophotometric and potentiometric methods. I1) j. HELLERand G. SCHWARZENBACH, Helv. Chim. Acta 24, 1876 (1951). c~ A. OK~,c and L. SOMMER,Z. anal. Chem. 143, 52 (1954); Anal. Chim. Acta 15, 345 (1956). t~ E. WARE, U.S.A., E.C. Rep. M D D C (1945).
NOTES
Exchange properties of ammonium salts of 12-heteropolyacids--V. Sorption of alkali metals on ammonium phosphomolybdatotungstate (Received 17 December 1962; in revised form 3 March 1963) HETEROPOLYAC1DShave been used for the precipitation of heavy alkali metalst~, ~ and their exchange properties have been described, t3,4~ Ammonium phosphomolybdate t4~ and ammonium phosphotungstate ~s~have been thoroughly investigated, and the present study describes the exchange properties of ammonium salts of phosphomolybdatotungstic acid (NH4PMoW) with various molar ratios of Mo:W. The uptake was studied under both static and dynamic conditions ~6~using acid ammonium salts of phosphomolybdatotungstic acids with varying molar ratios of M o : W (4:8, 6:6, 8:4). These were precipitated with an excess of 1 M NH4NO3 from aqueous solutions of the free heteropolyacids obtained by the etherate method ;t v~ analyses corresponded to the formula in Table 1. TABLE 1 Ion exchanger
Formula
Mol. Wt.
NH4PMo4Ws
(NH4)2,~sH0,4s[PMo4WaO~o]'6,5"H20
2666
NH4PMooWo
(NH4)z,6sHo,42 [PMosWsO~o]'7,6"H20
2510
NH~PMosW4
(NH4)~.48H0.52 [PMosW4040]" 5,7-H~O
2299
Figure 1 shows the uptake of Cs and Rb as a function of NH4 + ion concentration and demonstrates the ion-exchange nature of the process. Caesium is sorbed more easily than rubidium, in agreement with the values of the crystallographic radii, tsj Ka(Cs) decreases in the order NH4PMosW4 > NH4PMo6W~ > NH~PMo4Ws and from the measured Kd values for caesium and rubidium the theoretical value of the separation factor ~Rb cs was calculated to be 35 on NFI4PMo4Ws in 0.001 M HNO3. The effect of acidity on Ka at const. [NHa +] is practically negligible up to 2 M HNO3, but at higher acidity Ka decreases. ~a~ tll W. J. O'LEARY and J. PAP]SH, Ind. Eng. Chem. Anal. Edit. 6, 107 (1934). t~l M. H. FELDMANand L. E. GLENDENIN,l~. NES Part IV, 9, 654 (1951). tal H. BUCI~WALDand W. P. TmSTLE~-IWAITE,J. Inorg. Nucl. Chem. 5, 341 (1958). c4~j. VAN R. SM/T, J. J. JACOBSand W. ROBB, J. Inorg. NucL Chem. 12, 95 (1959). isJ j. K ~ L and V. KouklM, J. Inorg. NacL Chem. 12, 367 (1960). to~ j. KRTIL, Or. Inorff. Nacl. Chem. 19, 298 (1961). tT~A. I. KOKORINand N. A. POLOTEBNOVA,Zh. Obshch. Chim. 26, 1 (1956). ts) A. F. WELLS,Structural Inorganic Chemistry (2nd Ed.), Clarendon, Oxford (1950). ca~j. KRTIL, J. Inorg. NucL Chem. 24, 1139 (1962). 1191
1192
Notes
u~ 4
3
o.J
4
I
0
,
i
FIG. 1 . - - D e p e n d e n c e o f t h e d i s t r i b u t i o n coefficients Ka o n e q u i l i b r i u m c o n c e n t r a t i o n of ammonium ions in the solution. A , .. NH4PMo4W8
B . . . NI-I4PMo6We
C . . . NH4PMosW4
A--C indicates Cs
[ H +] = [0,001 M]
D ....
Kd ....
D ....
indicates Rb indicates NH~PMo4Ws
ml/g
CN,~No 3 , . m o l a r i t y o f N H ~ N O 3
Notes
1193
Dynamic experiments Microquantities of Cs and Rb were found to be sorbed in neutral media (0.4 M NaNO3) and also in strong acids (12 M HCI, 12 M HNO3). 1 M NH4NO3 elutes Rb quantitatively, and caesium can be eluted quantitatively with 10 M NH4NO3. Satisfactory results were also obtained with
Rb
C/Co
0
[
7OO
0
I 200
300
400 ,q
FIG. 2.~Separation of trace S~Rb from trace ~37Cs. Column: 1"13 cm ~ × 12cm, ion exchanger: NH4PMo4W8 b e d - - 3 cm, weight ratio NH4PMo4Ws: asbestos = 1:1, drop interval 15 sec. C/Ca . . . . volume per cent of alkali in I drop of eluate n...
number of drops
macro-amounts of Cs. Figure 2 shows the separation of traces of Rb from Cs on NH4PMo4Ws by elution with 1 M NH4NOa followed by 10 M NH4NO3.
Institute of Nuclear Research Chechoslovac Academy of Sc&nces Re~ u Prahy
J. KRTIL I. K~Iv,2
Spectrophotometric and potentiometric investigations on Mn (iii)-l:8 dihydroxy naphthalene 3:6 disulphonic acid chelate (Received 29 April 1963) IN RECENTyears the complexes of 1 : 8 dihydroxy naphthalene 3 : 6 disulphonic acid (chromotropic acid) have received considerable attention since many of them find uses in analytical chemistry. SCHWARZEr'raACH~1~made a detailed study of the Fe(iii) chelate while SOMra~R~ and coworkers carried out an extensive study of the Ti(iv) complexes and they have been used for the colorimetric estimation of Ti(iv). WARE~3~suggested the use of this reagent for the determination of uranium. Little has been done on the interaction of unstable oxidation states with chromotropic acid. In the present communication the results of the interaction of chromotropic acid with Mn(iii) described employing spectrophotometric and potentiometric methods. I1) j. HELLERand G. SCHWARZENBACH, Helv. Chim. Acta 24, 1876 (1951). c~ A. OK~,c and L. SOMMER,Z. anal. Chem. 143, 52 (1954); Anal. Chim. Acta 15, 345 (1956). t~ E. WARE, U.S.A., E.C. Rep. M D D C (1945).