Synthesis of Biodiesel Over Zirconia Supported Isopoly and Heteropoly Tungstates
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SYNTHESIS, CHARACTERIZATION ANDAPPLICATION OF ANTIMONY(V) ISOPOLY
ACID ION EXCHANGERS
Reetha Nanu Cheruvalath “Studies on some ion exchangers” Thesis. Department of Chemistry, Sree Narayana Post Graduate College, University of Calicut, 2006
CHAPTER I11
SYNTHESIS, CHARACTERIZATION AND APPLICATION OF ANTIMONY(V) ISOPOLY
ACID ION EXCHANGERS
Among the synthetic ion exchangers, insoluble salts of polybasic acids
and polyvalent metals had been studied extensively. Preparations of both
polycrystalline and amorphous compounds have been reported, among which
zirconium phosphate is the most widely studied one. Several other gelatinous
salts of titanium antimonate, -arsenate, -1nolybdate and -tungstate had been
studied as cation exchangers. Some of these were found to be more effective
than zirconiuin phosphate for specific purposes. Other compounds studied
include vanadate, tellurate, silicate, oxalate, salts of thoriuin(IV), cerium(IV),
aluminium(III), iron(III), chromium(III), uranium(VI), etc.. Recent
developn~ents in the study of such materials have led to a successful
preparation and characterization of well defined crystalline compounds. They
had layered structure and exhibited ion exchange properties. Knowledge of
the crystal structure gave a deeper understanding of their ion-exchange
processes and reversibility as well as a firm basis for the interpretation of their
therinodynainic properties.
Exchangers containing pentavalent metal ion, especially, antimony
have not been studied in much detail. The only laown antimony based ion
exchangers are antimonic acid1'', antiinony(V) silicatelS5 antimony
pentoxide156. Therefore, synthesis and ion exchange properties of the
following six antimony(V) based isopolyacid ion exchangers having different
anionic part are presented in this chapter. They are antimony(V) iodate,
antimony(V) selenite, antimony(V) vanadate, antimony(V) tellurite,
antimony(V) arsenite and antimony(V) arsenate. As the synthesis,
characteristion and application of these exchangers are similar, colnlnon
experimental procedure are given below.
3.1 Experimental
3.1.1. Reagents und solutions
Potassium pyroanti~nonate (made in Germany) and potassium iodate,
sodium selenite, sodium vanadate, sodium terllurite, sodiuin arsenite and
sodium arsenate (all BDH) were used. The other chemicals used were of
analytical grade. Double distilled water froin pyrex glass distillation unit and
calibrated measuring vessels were used. The following solutions were
prepared:
I. 0.05 and 0.1M solutions of potassiu~n pyroantimonate.
. . 11. 0.05 and 0.1 M solutions of potassium iodate, sodium selenite, sodium
vanadate, sodium tellurite, sodiuin arsenite and sodiun~ arsenate.
iii. 0.1 M standard NaOH.
iv. 1.0 M solutions of LiCl, NaC1, KC1 and BaC12
3 5
v. 0.005M solutions of Cd(II), PbCII), Zn(II), Ca(II), Cu(II), Ni(II),
Mg(II), Hg(II), Co(II), Al(III), Bi(II1) and Th(1V) salts.
vi. 0.005 M EDTA solution.
vii. 0.00 1 M, 0.0 l M and 0.1 M solutions of HN03 and NH4N03
Glass columns (id 1.1 cm) were used for column operations. A digital
pH meter, MK V1 (Csistromics) was used for pH measurements. Calibrated
glass wares were used for volumetric analysis. Thermal stability
measurements were performed using muffle furnace. For IR studies Perkin
Elmer model was used. For TG-DTA Lab: METTLER TOLEDOS R system
were used.
3.1.3 Syntlt esis
All the antimony(V) isopoly acid ion exchangers mentioned were
prepared according to a common method; i.e., aqueous solutions of potassium
iodate, sodiuin selenite, sodium vanadate; sodiuin tellurite, sodiuin arsenite or
sodium arsenate were added to acidic solution of potassium pyro antiinonate
in different concentration, pH, and mixing ratios. The mixture was stirred well
and the pH was adjusted using aqueous ammonia. The precipitate thus
obtained was allowed to stand in their respective mother liquor for 24 h at
room temperature. The precipitate was then filtered, repeatedly washed with
distilled water and dried at room temperature. The H+ form of the exchanger
was obtained by immersing the sample in 1M HN03 for 24 h and filtered,
washed with distilled water and dried at room temperature and stored over
NH4C1 in a desiccator. The different products obtained in 100- 150 mesh were
used in all experiments.
3.1.4. Clt emical conzposition
The composition of the exchanger was determined using a solution
obtained by dissolving a known amount of antimony(V) isopolyacid ion
exchanger in concentrated mineral acids. The antimony was determined as
pyrogallate. 157a Iodate as silver iodide157b, selenite gravimetrically'57c,
vanadate as silver ana ad ate'^^^, Tellurite as ~ e l l u r i u m ' ~ ~ ~ , asrinite was
determined by t i t r i m e t r i ~ a l l ~ ~ ~ ~ ' and arsenate gravimetrically a silver
arsenate'57g.
The IR spectra of the exchangers in H+ form using KBr disc on a
spectrometer and the thermogravimetric analysis of the exchanger in H+ form
was performed at a heating rate of 10°C/ min.
3.1.5. Determination of ion exchange capacity
The ion exchange capacity of material in H+ forin was determined by
column operation. The ion exchanger ( l .0 g) was placed in the column with a
glass wool support. Sodium chloride (1.0 M) was used as the eluent, and 200
m1 of eluate was collected in each case. The flow rate was maintained at 0.5
in1 inin-' The hydrogen ions separated from the coluinn were determined
titrimetrically with standard NaOH, The exchange capacity (ineqlg) was
a.v evaluated using the formula, -, where 'a' is the molarity, v is the volume of
W
alkali used during titration and W is the weight of exchanger taken. Exchanger
could be regenerated thrice without any appreciable loss of exchange
capacity.
3.1.6. Effect of temperature on ion exchange cripacity
1 g of the exchanger was heated for 3 h at various temperatures in a
thermostatically controlled hot air oven. The ion exchange capacities of the
heat treated samples were determined by the coluinn inethod after cooling
them to room temperature as described above.
The effect of electrolyte concentration on distribution coefficient was
studied by immersing the exchanger in solutions of the metal ions in various
concentrations of electrolytes (HN03, NH4N03, etc.) for 24 h, and
determining the Kd values by batch process.
3.1.7. pH titration curves
The pH titrations were performed by method of Topp and ~ e ~ ~ e r ' ' ~ .
About 500 ing portions of the exchanger were placed in 250 m1 conical flasks
and equiinolar solutions of alkali metal chlorides and their hydroxides in
different voluine ratios were added. The final voluine was restricted as 50 m1
to maintain a constant ionic strength. The pH of the solution was recorded
after every 24 h until equilibrium was obtained. The results were plotted to
get the pH titration curves.
3.1.8. Distrib crtion coefficient
The distribution coefficients (Kd) for different inetal ions in aqueous
media were deterinined by batch operations. 100 mg of the exchanger beads
in the H' form were equilibrated with 20 m1 of each metal ion solution for 24
h. The deterininations were carried out volumetrically using EDTA as the
titrant. Distribution coefficients were calculated by the formula,
where I is the initial volume and F is the final volume of EDTA; V is volume
of metal ion solution and A is weight of exchanger taken.
3.1.9. Sepnrntiolz of metal ions
The exchanger in H+ form (100 - 150 mesh size, 5g) was used for
coluinn operation in a glass tube having an internal size of (30 cm X 1.1 cm).
The column was washed thoroughly with distilled water and the mixture was
loaded. After recycling 2 or 3 times to ensure complete adsorption of the
mixture on the coluinn bead, the metal ions were eluted at a flow rate of 0.5
inllmin. The inetal ions in the effluent were determined quantitatively by
titration with EDTA. The metal ion concentrations in all cases were 0.005M
for binary and ternary separation, and 5 m1 of each of metal ion solution were
used. The separation was achieved by passing a suitable eluent through the
column. The eluents used were HC1, NH4N03, HN03, etc. in different
molarity.
3.2. Results and discussion
3.2.1. Atztiurzony(v iodate
Various samples of antimony(V) iodate (Table 1) have been prepared
in different conditions. As per Table 1, the sample No. l showed maximum
ion exchange capacity (2.39 meqlg) and hence it was used for the present
investigations. Although all inorganic exchangers dissolve completely in
alkaline medium, antimony(V) iodate exhibited significant insolubility in 0.0 1
M NaOH. However, it dissolved in 0.1 M NaOH. The exchanger was stable
in acetic acid, alcohol, 1.0 M solutions of HC1, HN03, LiC1, KC1, MgC12,
CaC12 and BaC12. It could be regenerated thrice without appreciable loss in
capacity.
IR spectra of the sample showed the following five bands at the
frequency ranges, 3401, 2363, 1629, 1350 and 741 cm'. The strong and
broad band at 3401 cm-' is characteristic of free water and OH groups. The
bands of strong intensities at 2363 and 1629 cm-' also represent the free water
molecules. Bands at1350 and 741cin-' are due to 1-0 and Sb-0 stretching
vibrations, respectively.
Therinoanalytical investigations threw some light on the empirical
formula and theoretical exchange capacity of the sample. The weight-loss up
to 390°C can be correlated to the loss of 3.34% of water. Assuming the
weight-loss at this temperature and the data obtained from chemical analysis,
the composition of the sample was fixed as Sb2051205. The number of moles
of water losed per Sb205 formula weight of the exchanger can be calculated
by the method of ~ lbe r t i '~ ' . If 'n' is the number of water molecules per mole
of mixed oxide, from the equation,
where X is the percentage of water content, and (M+18n) is molar mass of the
material. From this the number of water molecules was found to be n - 10.
Therefore, the formula assigned was Sb205120510H20
The effect of size and charge of the in going ion on the capacity of the
exchanger is shown in Table 2 for the alkali and alkaline earth metal ions.
The sequence shown by antimony(V) iodate is as follows.
Usually, at low aqueous concentrations and at ambient temperatures,
the extent of exchange increases with increasing valency of the ingoing ion,
ie. Ca(I1) > ~ a ( 1 ) ' ~ ~ ' . Antirnony(V) iodate did not obey this. The solubility
products of the corresponding iodates of the metal ion seemed to be
responsible for the deviation from normal behaviour. Under similar conditions
in the case of univalent ions the extent of exchange usually increases with
decrease in size of the hydrated cation.
K(1) > Na(1) > Li (I)
In the case of antimnony(V) iodate this sequence was found to be followed.
Antiinony(V) iodate retained about 80% of its exchange capacity after
drying at 100°C. The decrease in capacity on heating is due to the loss of
structural hydroxyl groups, bearing the exchangeable protons.
Distribution coefficients for eleven metal ions in demineralised water
(Table 3) showed a sequence, Ca(I1) > Cd(I1) > Cu(I1) > Pb(II)> Ni(I1) >
Hg(I1) > Mg(I1) > Co(I1) > Zn(I1) > Al(II1) > Th(1V). Effect of electrolyte
concentration on the distribution coefficient for certain inetal ions, such as,
Cd, Cu, Pb, etc. showed that increasing electrolyte concentration decreased
the distribution coefficients. These studies are important to find out the
elution behaviour. This observation is a general concept which is same for
all exchangers.
For binary -on, s & h w of metal ians of concefl~w 0,005M I
- ~ s ~ ~ ~ 1 o f c ~ - ~ ~ ~ , T h o , ~
a m i ~ w e r e a c h k v e d ~ g a ~ ~ @ f ~ e m b g e c Theel~e~ltsused
were ]HNOs -Q, H@ @ v d w $ &&m ("hbie 4). The m e r y
Q' 2 4 8 ' :
.- - mWb of -OH bm added
. - . - . .
Ibe pH titration -a obtained under qdiMum d t i m for NsUWPSICI,
KOWKCl and B t r ( O m C 1 2 showed W the exchanger was
mmofhct id as given in the figwe 3.
Table 1 . Conditions of synthesis and properties of' antitnony(V) iodate
Table 2. Effect of size and charge of the exchanging ions and temperature on the exchange capacity of antimony(V) iodate
Sample
1
2
3
4
1 5
Effect of size and charge 1 Effect of temperature
Hydrated Ion Exchanging exchange
ionic radii ion (A0)
capacity (1neq/g)
Molarity of reagent
Li (I)
Na (1)
I( (1)
Mg (11)
Ca (11)
Sr (11)
Ra (11)
Mixing ratio
1:l
1:l
1 : 1
2: 1
I 2:l
S b(V)
0.10
0.05
0.05
0.10
Ion exchange capacity (1neq/g)
10~-
0.10
0.10
0.05
0.10
PI-1
2
2
2
2
1 2 1 0.10 I 0.10
Colour of H' form
White
White (low yield)
White
White
1 White
Ion exchange capacity (mecl/g)
2.39
1.90
2.15
2.15
1.95
Table 3. llistribution coefficients of some nictal ions on antimony(V) iodate
Table 4. Binary separations on antimony(V) iodate
Cation
Zn.(l l)
Cd(ll)
Hg(ll)
Pb(l l)
Mg(ll)
Ca(l1)
Cu(ll)
Co(ll)
Ni(ll)
AI(III)
Th(lV)
Taken us
Sulphate
Nitrate
Chloride
Nitrate
Sulphate
Chloride
Sulphate
Sulphate
Chloride
Nitrate
Nitrate
Mixture of metal ions
HE;(II)
Cd(I1)
Pb(I1)
Cd(I1)
Al(II1)
Cd(I1)
Th(1V)
Cd(I1)
Kd(mllg)
Eluents
0.01M HN03
0.1 M NNNO3 + 0.5M NH4N03
0.01M HN03
0.1 M NI-103 -I- 0.5M NH4N03
0.01M HN03
0.1M I-IN03 + 0.5M NH4N03
0.01M HN03
0.1M I-IN03 + 0.5M NH4 NO3
water
72.70
1166.00
114.00
146.40
103.95
Complete uptake
245.45
101.20
125.71
34.35
9.25
Metal ion loaded (mg)
2.80
2.80
3.80
2.80
1.32
2.80
4.20
2.80
0.1M HNO3
15.00
255.00
32.00
28.00
20.00
255.00
82.00
23.00
32.00
10.00
0.00
Recovered (mg)
2.80
2.79
3.78
2.79
1.32
2.79
4.20
2.78
0.01 M HN03
38.25
612.00
84.00
85.00
65.00
355.00
125.00
48.00
82.00
20.00
5.20
0.1 M NH4N03
25.00
450.00
48.00
55.00
32.00
350.20
88.00
28.00
42.00
15.00
0.00
0.001 M HN03
68.00
1055.0
110.00
130.00
100.0
630.00
230.00
100.00
120.00
34.00
9.00
0.01 M NH4N03
56.34
834.00
88.00
110.00
85.00
700.00
155.00
68.00
85.00
25.00
6.25
0.001 M NH2N03
70.04
110.0
113.00
145.00
102.00
complete uptake
240.00
101.00
125.00
34.00
9.27
3.2.2. Antimorty(V) selenite
Various samples of antimony(V) selenite (Table 5) have been prepared
at different concentrations. It was obtained as white amorphous powder. It is
evident from Table 5 that the sample No.1 showed maximum ion exchange
capacity (2.22 meqlg) and hence it was used for the present investigation. The
exchanger dissolved slightly in alkaline medium and was stable in 1.0 M
solutions of mineral acids and salt solutions. It could be regenerated thrice
without any loss in capacity.
IR spectra of the sample revealed the following data. There are seven
peaks in the spectrum at the frequency ranges 3782, 3418, 2364, 1635, 1415,
121 1, 753 and 464 cm". The strong and broad peak at 3418 cm-' is
characteristic of free OH groups. The sharp bands at 2364, 1635 and 1415
cm-' are assigned to water of crystallisation. The bands at 1219, 753 and 464
cm-' are due to Se-0 and Sb-0 stretching, respectively. Thermoanalytical
investigations threw some light on the formula and theoretical exchange
capacity of the sample. The weight-loss up to 100°C was found to be 4.92%
and correlated will with the loss of 4.9175 % water. The co~nposition of the
sainple by chemical analysis was found to be Sb203.Se02. The number of
moles of water lost per formula weight of the exchanger can be calculated by
the method of ~ l b e r t y ' l ~ . If n is the number of water molecules per mole of
the mixed oxide from the equation as explained earlier in the section 3.2.1 and
it is found to be 2.4. Hence the formula of the compound could be
ascertained as Sb2O5. Se02.2H20.
The effect of size and charge of the ingoing ion on the capacity of the
exchanger is shown in Table 6 for the alkali and alkaline earth metal ions.
The sequence shown by Antimony (V) selenite is as follows.
At low aqueous concentrations and at ordinary temperature the extent of
exchange increases with increasing charge of the exchanging ion ie. ~ a '
ca2+ . Antimony(V) selenite followed this sequence under similar conditions
and constant charge. For singly charged ion, the extent of exchange increases
with decrease in size of the hydrated cation.
This sequence was found to follow in the case of antiinony(V) selenite as
well.
Antimony(V) selenite retained about 45% of the exchange capacity
after heating at 300°C (capacity 0.95). The decrease in capacity may be due
to loss of water molecules from the exchanger.
Effect of electrolyte concentration on the distribution coefficient for
certain metal ion like Ca, Mg, Th(IV), etc. showed that the distribution
coefficierrts demased witb in- of e1eddyk ooncentmticm and may be I
h adle camp&h&dmin tfieel-w.
The pH thtiofl CIWes shawed tbat the e x c h m p was
m o n o ~ ~ ~ m in figure.
For biaary @on, mlutims of metal ions of ootlcefl~un 0.005M
wmused. ~ ~ ~ ~ o f P b @ ) ~ H g O a n d ~ , C d @ ) f r o m ~
ThCIV) and M@) from C@) wem achieved on a cciIumn of the exchanger*
The elelnents used were I-IN0, andNI-14N03 and I-ICI at various dilutions
(Table 8). The recovery ranged froin 98 - loo%, with variation of 1% for
repetitive deterininantion.
Separation of ternary mixtures such as Pb(I1) from Th(IV), Hg(II),
Cd(I1) froin Th(IV), Ng(I1) and Mg(I1) froin Zn(II), Ca(I1) were successfully
achieved Table (9).
Table 5. Conditions of synthesis and properties of antimony(V) selenite
Salnple
1
2
3
4
5
Molarity of reagent
Sb(V)
0.1
0.05
0.05
0.1
0.1
Mixing ratio
1:l
1:l
1.1
1:2
2: 1
ScO,'
0.1
0.1
0.05
0.1
0.1
Colour of H' forin
White ainorphous
I I
I I
I I
I I
p13
2
1
h 3
2
2
Ion exchange capacity (meq/g)
2.22
1.70
1.35
1.20
1.10
Table 6. Effect of size and charge of the exchanging ions and temperature effect on the exchange capacity of antimony(V) sclenite
Effect of size and charge I I
Effect of temperature
Exchanging ion
Table 7. Distribution coefficients of some metal ions on antimony(V) selenitc
Temperature ("C)
Hydrated ionic radii
(A0)
Ion exchange capacity (1neq/g)
Ion exchange capacity (meq/g)
Cation
Zn(ll)
Cd(ll)
Hg(ll) Pb(1l)
Mg(ll) Ca(ll)
Cu(ll)
Co(ll)
Ni(l1)
AI(! I I)
Th(1V)
Taken as
Sulphate
Nitrate
Chloride
Nitrate
Sulphate
Chloride
Sulphate
Sulphate
Chloride
Nitrate
Nitrate
K d (mllg)
Distilled water
14.86
812.50
42.16
983.00
191 1 .OO
256.00
132.20
124.24
24.63
52.96
4.55
0.1M HN03
0.00
112.00
2.00
2.45
21 5.00
15.00
10.00
8.00
0.00
0.00
0.00
0.01M HNOs
6.25
432.00
12.05
535.00
810.00
125.00
66.00
75.00
6.30
10.20
0.00
0.001 M HN03
13.80
805.00
40.00
953.00
1851 .OO
255.00
130.00
120.00
23.00
50.00
1 .OO
0.100M NH4N03
2.00
215.00
12.00
340
372.00
25.0
22.00
7.00
1.25
5.55
0.00
0.001M NH4N03
8.05
630
28.00
635
888
185
85.0
90.00
8.50
25.00
0.05
0.001M NH4NO3
14.00
810.00
41.00
982.00
1855.00
250.00
132.00
120.00
24.00
50.00
3.500
Table 8. Binary separations on antimony(V) selenite
Pb(I1) 0.02M IHNO; + 0.5 M NH4NO;
0.0 1 M I-INO;
Mixtures of lnetal ions
Table 9. Termary separations on antimony(V) selenite
Eluents
Mixtures of metal ions
Th(IV)
%(I0
Pb(I1)
Metal ion Loaded
( W >
Recovered (1%)
Eluents
0.01M I-IN03
0.1 M HNO;
0.2 M HNO; + 0.5 M NH4NO3
Metal ion Loaded (mg)
4.20
2.80
3 .80
Recovered (1%)
4.20
2.78
3.75
Different sainples of antimony(V) vanadate have been synthesized
(Table 10). It was obtained an yellow ainorphous powder. It is evident from
Table 10 that the sainple No. 1 showed lnaxilnuin ion exchange capacity (2.03
meqlg) and hence it was used for further investigation. Although all ion
exchangers dissolve coinpletely in alkaline medium, animony(V) vanadate
exhibited significant chemical stability in O.1M NaOH. However, it dissolved
in 1.0 M NaOI-I. It was stable in 1.0 M lnineral acids and 1.0 M salt solutions.
It could be regenerated thricc without appreciable loss in capacity.
The IR spectrum showed bands at 3786 and 3402 (broad) and 722
cm". There are sharp bands at 2364, 1629, 1404 and 967 cm-'. The band at
3402 cm-' can be assigned to water of hydration. The band at 1629 cm-' can
be assigned to water of crystallisation. Mctal-oxygen stretching vibrations
have been assigned at 722 and 967 cm-'.
Chemical coinposition was found to be 1:l. TGA curve showed the
reinoval of water lnolecule at 95OC. This corresponds to a loss of about 3
water lnolecules per mole of the exchanger as pcr Alberty equation. I-Ience
the formula proposed was Sb205.V20531-120.
The effect of size and charge of the ion and that of the temperature on
ion exchange capacity were found to be similar as observed in previous cases
(Table 11). Distribution coefficients for eleven rnetal ions in dernineralised
Table 10. Conditions of synthesis and properties of antimony(V) vanadate
Table 11. Effect of size and charge of the exchanging ions and temperature on the exchange capacity of antimozj.(\~ vara2r;te
pH
1
1
1
1
1
Mixing ratio
1:l
1:l
1:l
1 :2
2: l
Sample
1
2
3
4
5
Effect of size and charge
Colour of form
Yellow amorphous
Pale yellow I1
I!
1 1
Molarity of reagent
Exchanging ion
Li(1)
Na(I)
Mg(II)
Ca(I1)
Sr(I1)
B a(I1)
Effect of temperature
Ion exchange capacity (meq/g)
2.03
1.89
1.36
1.20
1.10
Sb(V)
0.05
0.1
0.05
0.1
0.1
Temperature ("C>
5 0
100
200
300
V03-
0.05
0.05
0.1
0.1
0.1
Hydrated ionic radio (A0)
3.4
2.76
2.32
7.00
6.30
6.10
5.90
Ion exchange capacity (1neqk)
2.03
1.20
Ion exchange capacity (meq/g)
1.98
2.03
2.36
1.85
1.97
1.9
2.25
Table 12. Ilistribution coefficients of some metal ions on antimony(V) vanadate
Table 13. Binary separations on antimony(V) vanadate
Cation
Zn(ll)
Cd(ll)
Hg(ll)
Pb(ll)
Mg(ll)
Ca(ll)
Cu(ll)
Co(ll)
Ni(ll)
AI(II1)
Th(lV)
Mixtures of inetal ions
Eluents
Taken as
Sulphate
Nitrate
Chloride
Nitrate
Sulphate
Chloride
Sulphate
Sulphate
Chloride
Nitrate
Nitrate
K d (mllg)
Metal ion Loaded
(111g)
Distilled water
892.24
691.66
683.30
734.37
59.68
613.04
158.30
C.U
85.29
87.30
1227.70
Recovered (1%)
Ni(I1)
Th(1V)
0.1M HN03
223.00
125.00
123.00
136.00
2.00
132.00
13.00
650
12.00
13.00
288
0.1 M HCI
0.1 M I-IN03 + 5M NH4NO;
0.01M HN03
435.00
232.00
230.00
242.00
28.55
248.00
78.00
1200
28.00
25.00
633
3.20
4.20
3.20
4.20
0.001 M HN03
890.00
690.00
682.00
734.00
59.00
612.00
156.00
1800
84.00
85.00
1200
0.100 M NH4N03
320
142
148
152
12.00
128.00
23.00
700.00
16.00
15.00
312
0.001 M NH4NOj
580
255
260
272
36.00
252.00
92.00
1450
32.00
30.00
688
0.001M NH4N03
891.03
691 .OO
683.00
734.30
59.60
613.00
158.00
came to uptake
85'.00
87.00
1225.00
Antiinony(V) tellurite obtained was white a~norphous powder (Table
14). The inaxiinu~n ion exchange capacity was found to 1.02 ~neqlg. The
exchanger was stable in dilute alkaline medium, in 1.0 M mineral acids and
1.0 M inetal salt solutions. It could be regenerated thrice without any
appreciable loss in capacity.
IR Spectra of the sample had eight band at the frequency range 3782,
3400, 2363, 1591, 1385, 961 and 73 1 cm-'. The strong and broad band at
3400 cm-' is characteristic of free water inolecule and hydroxyl group. The
bands at 2363 and 1591 cm-' also represent the free water molecules. The
bands at 1385, 1074 and 696 cm-' are due to Sb-0, Te-0 stretchings
respectively.
Ther~noanalytical investigation threw some light on the ~nolecular
formula and theoretical exchange capacity of the sample. The weight-loss,
25.19% correspondcd to 13 water inolecules as per the ~ l b e r t i ' ~ ~ method.
Froin the chemical analysis the inole ratio obtained was 2:l . Hence the
forinula of the exchanger was ascertained as Sb2O5, Te03, 13H20.
The effect of size and charge of the ion and temperature and the ion
exchange capacity, effect of electrolyte conce~ltration on distribution
coefficient were found to be in accordance with theory and is similar as
observed in the previous sections (Table 15).
W-., v?--
Mbntim ooefflcients of 12 metal ium in dimin&& water (Table
1 6 ) w e ~ e f a r m d i ~ t b e ~ c e :
Cu(1I) - I-Ig(II), Pb(I1) - Cu(II), Ni(I1) - Cu(II), Cd(I1) - Cu(I1) and Th(1V) -
Cu(I1) were achieved on the coluinn (Table 17).
Table 14. Conditions of synthesis and properties of antimony(V) tellurite
Table 15. Effect of size and charge of the exchanging ions and temperature on the exchange capacity of antimony(V) terrluite
Effect of size and change
Exchanging ion
Li(1)
W 1 1
K(I)
Mg(II)
Ca(I1)
Sr(I1)
B a(I1)
Effect of temperature
Temperature ("c)
5 0
100
200
300
I-Iydrated ionic radii
3.4
2.76
2.32
7.00
6.30
6.10
5.90
Ion exchange capacity (1neqIg)
1.02
0.98
0.58
0.44
Ion exchange capacity (1neqk)
0.95
1.02
1.21
0.85
0.88
0.92
1.35
Table 16. Distribution coefficients of some lllctal ions on antimony(V) telllirite
Table 17. Binary separations on antimony(V) tellurite
Cation
Zn(ll)
Cd(ll)
Hg(ll)
Pb(l1)
Mg(ll)
Ca(1l)
Cu(ll)
Co(ll)
Ni(ll)
AI(I1I)
Bi(lll)
Th(lV)
Taken as
Sulphate
Nitrate
Chloride
Nitrate
Sulphate
Chloride
Sulphate
Sulphate
Chloride
Nitrate
Nitrate
Nitrate
Mixtures of inetal ions
Hg(II)
CU(II)
Pb(I1)
Cu(I1)
Ni(I1)
Cu(I1)
Cd(I1)
Cu(I1)
Th(1V)
CU(II)
Kd (mllg)
Eluents
0. 1 M I-INO;
0.1M MNO; + 0.5 M NH;NO;
0.1M HNO;
0.1M HNO; + 0.5 M NN4N03
0.1M I-IC1
0.1M I-IN03 + 0.5 M NH4N03
0.1M HNO;
0. l M NNO; + 0.5 M NI-14N03
0.01 M I-INO~
0.1 MHN03 + 0.5 M NH4 NO;
Distilled Water
81.25
23.04
32.00
62.50
62.50
207
389.20
135.24
25.74
11.45
1250.90
74.39
Metal ion Loaded
( W )
2.80
1.30
3.80
1.30
3.20
1.30
2.80
1.30
4.20
1.30
0.1M HN03
16.23
0.00
6.00
13.00
12.00
82.10
112.00
23.00
0.00
0.00
285
13.00
Recovered (1ns)
2.75
1.30
3.78
1.30
3.20
1.30
2.78
1.30
4.15
1.30
0.01M HN03
38.45
2.30
17.35
29.35
25.00
188.00
189.00
86.00
16.00
2.35
712.00
29.00
0.001 M HNOJ
80.25
22.85
31.50
81.25
62.00
205.00
380.00
130.00
25.00
10.00
1200
70.00
0.001M NH~NOJ
81.00
23.00
32.00
62.00
62.00
207.00
389.00
135.00
25.00
11.50
125.00
75.00
0.1 M NH4N03
20.15
0.00
7.35
12.25
15.00
92.00
125.00
28.00
0.00
0.00
325
18.00
0.01 M NH4N03
39.25
10.30
19.38
20.35
32.45
190.00
213.00
95.00
0.00
8.00
950
85.00
3.2.5. Antimo~zy(v arsenite
Various samples of antimony(V) arsenite have been prepared at
different conditions (Table 18). It is evident from the table 18 that the sainple
l showed inaxiinuin exchange capacity (2.89 ineqlg) and hence it was used
for the present investigation. It was obtained as white a~norphous powder.
The exchanger was stable in 1.0 M mineral acids and l .O M solutions of metal
salts. The exchanger could be regenerated four times without any
appreciable loss in capacity.
IR spectra of the sample showed the following features. There are six
bands in the spectrum at the frequency ranges, 3397, 2363, 1630, 1401, 1072,
773 and 616 cmm'. The bands at 3397, 2363, 1630 and 1401 cm-' are due to
0-H of water molecules. The bands at 1072, 773 and 616 cm-' are due to
inetal oxygen stretching vibrations.
Therinoanalytical investigations could be used to calculate the
~nolecular forinula and theoretical exchange capacity of the exchanger. The
weight-loss upto 100°C can be correlated to the reinoval of water ~nolecule
and is equal to 16.22%. The coinposition of the sainple by chemical analysis
was Sb205.As203. By the method of ~ l b e r t ' ~ ~ , the number of water molecules
present was 1 1. Hence the forinula ~nolecule was Sb205.A203. 1 1 I-120.
The effect of size and charge of the ingoing ion on the ion exchange
capacity of the exchanger is shown in Table 19. For the alkali and alkaline
earth inetal ion, the sequence shown by the exchanger was in accordance with
theory and was similar to the observations in the case of the other exchangers.
The effect of electrolyte concentration on distribution coefficient and
effect of temperature on ion exchange capacity of the exchanger showed that
the distribution coefficients decreased with increase in concentration and ion
exchange capacity decreased with increase of temperature.
Distribution coefficients for 12 inetal ions in demineralised water
(Table 20) decreased in the following sequence: Ni(I1) > Bi(II1) > Mg(I1) >
Hg(I1) > Ca(I1) > Pb(I1) > Th(1V) Cu(I1) > Zn(I1) > Cd(I1) > Co(I1) > Al(II1).
The pH titration curves shows that the exchanger was monofunctional
with respect to NaOHNaCl, KOHIKC1 and Ba(OH)2/BaC1 systems.
The important binary separations carried out on the exchanger column
were: Cd(I1) - Hg(II), Cd(I1) - Pb(II), Al(II1) - Th(IV), Al(II1) - Mg(I1) and
Cu(I1) - Ni(I1) as detailed in the Table 21.
I - .
h i L d -
Ir
M W t y of mqgent loa '
hfkiag &l~kUOf e~dlatlp
m. As03- ratio pH Wfam
1 0.05 0.05 I:1 1 White 2.89 ; - ;X
rnwphu9; - 2 0.1 0.05 1:l 1 2.0 ,, n
3 0.1 0.1 1:l 1 n 1-86,
4 0.1 0.1 1:2 1 n 1 .S4 L -.
S Q. f Q. 1 2: 1 1 U
Table 19. Effect of size and charge of the exchanging ions and telnperature on the exchange capacity of antimony(V) arsenite
Table 20. Distribution coefficients of some metal ions on antimony(V) arsenite
Effect of size and charge
Exchanging ion
Li(1)
Na(I)
K m
M m )
Ca(I1)
Sr(I1)
B a(I1)
Effect of temperature
Cation
Zn(ll)
Cd(ll)
Hg(ll)
Pb(ll)
Mg(ll)
Ca(ll)
Cu(ll)
Co(ll)
Ni(ll)
AI(III)
Bi(lll)
Th(lV)
Temperature ("C)
5 0°
100"
200°
3 00"
Hydrated ionic radii
("A)
3.40
2.76
2.32
7.00
6.30
6.10
5.90
Ion exchange capacity (1neqJg)
2.80
2.50
1.96
1.34
Taken as
Sulphate
Nitrate
Chloride
Nitrate
Sulphate
Chloride
Sulphate
Sulphate
Chloride
Nitrate
Nitrate
Nitrate
Ion exchange capacity (1neq/g)
1.6
2.89
3.68
3 -00
3.20
3.50
4.5 1
- Kd (mllg )
Distilled Water
104.28
86.30
585.00
400.00
.625
406.06
124.19
58.37
C.U
20.20
1545.45
325.00
O.1M HNO3
16.05
11.00
125
1.30
145
15.00
18.00
0.00
2.10
0.00
285
85
0.01M HN03
42.05
42.85
258
250
285
185
85.00
25.00
625
0.00
725
220
0.001 M HN03
104.00
86.30
580.00
395.00
620
400.00
124.00
55.00
8.00
10.0
1400
320
0.1 M NH4N03
22.35
16.00
130
160
150
95
22.00
0.00
31 5
0.00
325
115
0.01 M NH4N03
52.00
58.00
265
285
325
210
90.00
26.00
625
10.00
890
235
0.001M NH4N03
104.20
86.00
585.00
400.00
625.00
405.00
124.89
58.00
C.U
20.00
1540.00
325.00
Tablc 21. Binary separations on antimony(V) arsenite
3.2.6. Antinzony(v arsenate
Mixtures of metal ions
Cd(I1)
Hg(II)
Cd(I1)
Pb(I1)
AI(II1)
Th(1V)
Al(II1)
Mg(II)
Cu(I1)
Ni(I1)
Different sainples of antimony(V) arsenate have been prepared under
different conditions (Table 22). The sample No.1 showed maximum ion
exchange capacity (2.60 meq) and obtained in good yield. The exchanger
obtained was white amorphous powder. It is stable in 1.0 M mineral acids
andl.O M metal salt solutions. It can be regenerated four tiines without any
appreciable loss in capacity.
IR spectra of the sample revealed the following. There were seven
bands in the spectruin at frequency range 3780, 3407.5, 2363, 1637, 1401,
Eluents
O.1M HNO;
0.2M MNO; + 15M NH4NO;
O.1M HN03
0.2M EINO; + 0.5M NIH4N03
O.1M MC1
O.1M I-INO; + 0.5M NI-14N03
O.1M HCI
0.1M HNO; + 0.5 M NH4N03
O.1M HCI
O.1M HN03 + 0.5M NH4N03
Metal ion Loaded
(1%)
2.80
2.80
2.80
3.80
1.32
4.20
1.32
2.40
1.30
3.20
Recovered (1%)
2.80
2.78
2.80
3.75
1.30
4.2 1
1.30
2.42
1.30
1.30
808 and 619 cm-' indicating the presence of water molecules and metal-
oxygen bands in the sample.
Therinoanalytical investigations could be used to determine the
formula and theoretical exchange capacity of the sample. The weight-loss
upto 100°C could be assigned to a water loss and is 1 1.0 1 %. Based on the
mole ratio determined by chemical analysis, the empirical formula assigned
was Sb2O5 - As04 nH20. Using the method of Alberti, the number of water
molecules found out as 5. Hence the formula of the exchanger was assigned
as Sb205As045H20.
The effect of size and charge of the ingoing ion on the capacity of the
exchanger (Table 23) for the alkali and alkaline earth metal showed by the
exchanger was as:
At low aqueous concentrations and at ordinary temperature the extent of
exchange increases with increasing charges of the ongoing ion, i.e., Ca(I1) >
Na(1). But antimony(V) arsenate did not show this sequence. The solubility
products of the corresponding arsenates of the metal ions may be responsible
for the departure from expected sequence.
The study of the effect of electrolyte concentration on distribution
coefficient and effect of temperature on ion exchange capacity of the
cmmdmtim and ion ex- cmacit#.demead with increase of
'g> Distn'bution coefficients shown ?y the exchanger fm 11 metal h
d e d n d s e d water (Table 24) were in the following s e q ~
w n o fmctid with respeGt to NaOrnaC1, KOWKCl and mda(OHyBaCh '
The important Binary separation performed on the column of the
exchanger were Cd(I1) - Pb(II), Hg(I1) - Pb(II), Th(1V) - Pb(II), Co(I1) -
Cu(II), Ni(I1) - Cu(II), Mg(I1) - Al(II1) and Mg(I1) - Ca(I1) and the ternary
separations carried out were Mg(I1) - Th(IV) - Pb(II), Mg(I1) - Ca(I1) -
Cu(I1) and Mg(I1) - Th(IV) - Cu(I1) (Table 25).
Table 22. Conditions of synthesis and properties of antimony(V) arsenate
Sample
1
Molarity of reagent Mixing
ratio
1:l
1:1
1:l
1:l
1:2
Sb(V)
0.05
0.1
0.05
0.1
0.1
As04'
0.05
0.05
0.1
0.1
0.1
1
1
1
1
1
Colour of H+ form
White alnorp hous
I 1
I I
t I
I I
Ion exchange capacity (1neq/g)
2.60
2.1 1
1.93
1.40
1.20
Table 23. Effect of size and charge of the exclianging ions and temperature on the exchange capacity of antimony(V) arsenate
Table 24. llistribution coefficients of some metal ions on antimony(V) arsenate
Effect of size and change
Exchanging ion
Li(1)
Na(I)
IW)
Mg(II)
Ca(I1)
Sr(I1)
B a(I1)
-
~ f f e c t of temperature
Cation
Zn(ll)
Cd(ll)
Hg(ll)
Pb(ll)
Mg(ll)
Ca(ll)
Cu(ll)
Co(ll)
Ni(ll)
AI(III)
Bi(lll)
Th(lV)
Temperature ("C)
5 0
100
200
Ion exchange capacity (1neq/g)
2.60
2.30
2.00
I-Iydrated ionic radii
("A)
3.40
2.76
2.32
7.00
6.30
6.10
5.90
Taken as
Sulphate
Nitrate
Chloride
Nitrate
Sulphate
Chloride
Sulphate
Sulphate
Chloride
Nitrate
Nitrate
Nitrate
Ion exchange capacity (1neqIg)
2.00
2.60
2.78
1.02
1.30
1.22
1.55
Distilled water
14.86
45.30
84.48
71 3.63
81 1.47
13.75
36.89
30.89
30.65
193.68
487.50
66.96
0.1M HN03
0.00
11.00
16.00
186.00
213.00
0.00
6.00
5.00
0.00
65.00
213.00
7.00
0.01M HN03
0.00
25.00
42.00
296.00
325.00
0.00
22.00
20.00
10.00
125.00
315.00
25.00
0.01 M NH4N03
0.00
28.00
35.00
450.00
512.00
0.00
25.00
26.00
25.00
155.00
360.00
35.00
K d (rnllg)
0.001 M HN03
5.00
40.00
80.00
629.00
810.00
10.00
35.00
28.00
30.00
190.00
480.00
66.00
0.001M NH4N03
10.00
45.30
84.00
713.00
81 1 .OO
12.50
36.80
30.60
30.60
193.00
487.00
66.90
0.1 M NHdN03
0.00
15.00
19.00
21 3.00
250
0.00
10.00
12.00
0.00
73.00
250.00
15.00
Tahlc 25. Separations on antimony(V) Arsenate
Mixtures of metal ions
Binary Separation
Cd(I1)
Pb(I1)
Hg(II)
Pb(T1)
Th(1V)
Pb(I1)
Co(I1)
Cu(I1)
Ni(I1)
Cu(I1)
Mg(II)
Al(II1)
Mid111
Ca(I1)
Ternary separation
Mg(II)
Th(1V)
Pb(I1)
M m )
Ca(I1)
Cu(I1)
Mg(II)
Th(1V)
Cu(I1)
Eluents
0.1 M HN03
0.1M Erno:, + 0.5M NH4N03
0.01M HN03
O.1M HN03 + 0.5M NM4 NO3
0. l M I-INO:,
0.1M HN03 + 0.5M NI-14N03
0 . 1 ~ IRJO~
0.1M m03 + 0.5M NH4N03
0.01 M HCl
0.1 M m03 + 0.5M NH4N03
0 . 0 1 ~ FJNO~
0.1 M HN03 + 0.5M NH4N03
0.01M HN03
0.1M HN03 + 0.5M NN4 NO3
0.01M NN03
0.1 M NM03
0.1 M HN03 + 0.5M NH4N03
0 . 0 1 ~ I-INO~
0.1 M I-INO~
0.1 M FIN03 + 0.5M NM4N03
0.1M FIN03
0.1 M
0.1M HN03 + 0.5M NI34N03
Metal ions Loaded
(mg)
2.80
3.80
2.80
3.80
4.20
3.80
4.00
1.30
3.20
1.30
2.40
1.32
2.40
2.50
2.40
4.20
3.80
2.40
2.50
1.30
2.40
4.20
1.30
Recovered (mg)
2.80
3.78
2.80
3.75
4.15
3.75
3.98
1.3 1
3.20
1.29
2.40
1.30
2.40
2.45
2.40
4.10
3.81
2.40
2.48
1.28
2.40
4.19
1.28
3.3. Summary
Six isopoly acid exchangers of antimony(V) reported here had
individual importance with regard to their specific preference for certain
metal ions.
The ion exchanger, antimony(V) iodate had greater specificity for
cadmium and calcium ions. This exchanger could be used for the separation
of cadmium from other metal ions and also for the waste water analysis.
Antimony(V) selenite was specific for magnesium and lead. This
exchanger could be used for the environmentally important heavy elements
separation.
Antimony(V) vanadate was useful in the separation of Thorium metal.
The exchanger had high affinity for thorium. Now-a-days thoriuin separation
from other metal mixtures as well as from nuclear waste disposals are very
important.
Antimony(V) tellurite was found to be specific for bismuth and hence
the separation of this metal could be carried out using the exchanger.
Antimony(V) arsenite also had high affinity for bismuth. Both these
exchangers could be used for the binary separation of heavy elements which
are important in the waste water treatment.
Antiinony(V) arsenate was found to be very useful for the separation of
copper as it had high affinity for copper. Also this exchanger could be used
for the treatment of waster water obtained from spinning and weaving mills.
Also the exchanger was found to be very useful in binary and ternary
separatioils.
Finally, the present investigation showed that these exchangers were
had high ion exchange capacities compared to other exchangers studied till
date, except antimony(V) tellurite.