Precipitation of bismuth(III) oxobromide from bromide media

Article abstract of DOI:10.1134/S1070427207120017

Abstract-X-ray phase analysis, thermogravimetry, IR spectroscopy, and chemical analysis were used to study bismuth(III) precipitation from nitrate solutions upon addition of aqueous solutions of hydrobromic acid or ammonium bromide, and from bismuth-containing hydrobromic acid solutions. The conditions in which bismuth(III) oxobromide of BiOBr composition is formed were determined and the possibility of obtaining a high-purity product was assessed.

Full text of DOI:10.1134/S1070427207120017

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 12, pp. 2015 2019.
Pleiades Publishing, Ltd., 2007.
Original Russian Text
pp. 1937 1941.
M.N. Novokreshchenova, T.V. Daminova, Yu.M. Yukhin, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 12,
INORGANIC SYNTHESIS
AND INDUSTRIAL INORGANIC CHEMISTRY
Precipitation of Bismuth(III) Oxobromide from Bromide Media
M. N. Novokreshchenova, T. V. Daminova, and Yu. M. Yukhin
Institute of Solid-State Chemistry and Mechanochemistry, Siberian Division, Russian Academy of Sciences,
Novosibirsk, Russia
Received August 27, 2007
Abstract Abstract X-ray phase analysis, thermogravimetry, IR spectroscopy, and chemical analysis were
used to study bismuth(III) precipitation from nitrate solutions upon addition of aqueous solutions of hydro-
bromic acid or ammonium bromide, and from bismuth-containing hydrobromic acid solutions. The conditions
in which bismuth(III) oxobromide of BiOBr composition is formed were determined and the possibility of
obtaining a high-purity product was assessed.
DOI: 10.1134/S1070427207120017
Bismuth oxobromide is used in veterinary medicine
1], in technology for manufacture of piezo-, pyro-,
sphere in the stage of preparation of bismuth nitrate
solutions. This is so because the dissolution process
is described in this case by the equation
[
and ferroelectric materials, and in physical develop-
ment of silver-containing photographic materials [2, 3].
This compound is obtained by dissolving bismuth
oxide of reagent-grade purity in hydrobromic acid,
with the subsequent dilution of the resulting solution
with hot water [4, 5]. A method is known for prepara-
tion of bismuth oxobromide, in which a mannitol-
containing aqueous solution of bismuth nitrate is re-
acted with an alkali metal bromide at pH 5.0 5.2 in
the presence of a buffer mixture based on urotropin
and hydrobromic acid [6].
Bi O + 6HNO3 = 2Bi(NO3)3 + 3H O.
(2)
2
3
2
Hydrobromic acid well dissolves bismuth oxide, as
also does nitric acid, and the dissolution reaction has
the form
Bi O + 6HBr = 2BiBr3 + 3H O.
(3)
2
3
2
It is of practical interest in this context to study
synthesis of bismuth(III) oxobromide directly from
solutions produced by dissolution of technical-grade
bismuth oxide in nitric or hydrobromic acid.
Bismuth compounds are commonly synthesized
from a metal of Vi1 brand (mass fraction of Bi 98%)
by dissolution of its grains in 9 M nitric acid, fol-
lowed by hydrolytic purification of bismuth to remove
impurity metals at pH 1.5 2.0 [7]. A disadvantage
of this method is in that toxic nitrogen oxides are re-
leased into the gas phase in the stage of preparation
of bismuth nitrate solutions, because the dissolution
process occurs in accordance with the equation
This communication reports on a study of the in-
fluence exerted by the concentration of bromide ions
and the process temperature on the purity and de-
gree of bismuth(III) oxobromide precipitation from
nitrate and bromide solutions. The metal was oxidized
in a stainless steel reactor equipped with a screw
for melt agitation. A single batch charged into the ox-
idation reactor was 150 160 kg. The metal was
melted at a temperature of 350 C and bismuth oxide
from the preceding stage of oxidation of metallic
bismuth was introduced in an amount of 20% into
the melt under agitation. The temperature was raised
to 600 C and the powder was agitated for 6 h.
The technical-grade oxide contained 88.4% bismuth.
Bi + 6HNO3 = Bi(NO3)3 + 3NO2 + 3H O. (1)
2
It has been shown [8] that preliminary oxidation of
metallic bismuth with atmospheric oxygen to give
a technical-grade oxide makes it possible to reduce
the expenditure of nitric acid by a factor of 2 and to
eliminate release of nitrogen oxides into the atmo-
2015

2016
NOVOKRESHCHENOVA et al.
Hydrolytic processing of technical-grade bismuth oxide I to give oxobromides II IV
Content, %
Product
Pb
Cu
Ag
Fe
Zn
Cd
3
4
4
6
5.0 10 2
3.0 10 3
5.6 10 3
1.0 10 3
5.8 10 4
2.0 10 5
3
5
5
6
I
II
III
IV
1.08
8.7 10
7.5 10
7.8 10
1.0 10
27 10
5.0 10
3.6 10
5.0 10
6.2 10 2
0.22
3
4
5
9.0 10
5.2 10
1.2 10
4.8 10 5
2.0 10 6
<1.0 10 4
1.0 10 5
Its composition (I) in terms of impurity metals is pres-
ented in the table.
diffractometer with Cu radiation, counter rotation
rate of 0.5 deg min , and I = 4000. Curves of dif-
K
1
ferential thermal analysis (DTA) and thermogravimetry
(TG) were measured for the samples under study on
an MOM derivatograph (Hungary) at a heating rate
A bismuth(III) nitrate solution containing 380 and
10 g l 1 of Bi(III) and free nitric acid, respectively,
1
was prepared by dissolving technical-grade oxide in 6
M nitric acid. The composition corresponded to that
of solutions commonly used in the technology of bis-
muth compounds. A bismuth(III) bromide solution
1
of 10 deg min . Electron microscopic images of
the products were obtained using a JSMT-20 scanning
electron microscope with a resolution of 200
.
1
1
The specific surface area of the samples obtained was
measured by the chromatographic method of thermal
desorption of argon. Macroscopic amounts of bis-
muth(III) in the liquid and solid phases were deter-
mined by titration with a solution of Complexon III,
with Xylenol Orange as indicator, and microscopic
amounts, by photocolorimetry in the presence of KI.
The concentrations of metals (Pb, Ag, Cu, Fe, Zn)
were determined by the atomic-absorption method
on a Saturn 2M spectrophotometer. The precipitation
products were preliminarily dissolved in nitric acid
(1 : 1). The concentration of nitrate ions was found by
voltammetry on a renewable copper electrode [9], and
that of bromide ions, on a silver electrode, after being
transferred to solution by preliminary treatment with
a sodium hydroxide solution (2 M) at 70 90 C.
containing 385 g l of bismuth and 70 g l of free
hydrobromic acid was obtained by dissolving technic-
al-grade bismuth(III) oxide in 7 M hydrobromic acid.
The volume ratio between the starting and final bis-
muth-containing solutions was 1 : 10. Upon addition
of hydrobromic acid or an ammonium bromide solu-
tion to the bismuth nitrate solution, it was adjusted
by addition of distilled water.
The bismuth-containing bromide solution was pro-
cessed by its dilution with distilled water (1 : 9). This
was done in glass vessels with the use of stirrers.
The mixture was agitated for 20 min. After settling for
0
.5 h, the precipitate was filtered off with the use of
a vacuum, washed on the filter with distilled water,
and dried in air. An X-ray phase analysis (XPA) of
the precipitation products was made on a DRON-3
The study of the hydrolytic processing of bismuth-
containing bromide solutions demonstrated that, upon
their dilution with distilled water (1 : 9), the degree
of bismuth(III) recovery into oxobromide at 25 and
65 C is 97.9 and 96.5%, respectively. In precipitation
of bismuth(III) from nitrate solutions by addition of
a hydrobromic acid solution, the dependence of the de-
gree R of metal precipitation on the molar ratio n
between bromide ions and bismuth in solution passes
through a maximum at 1.0 1.1 (Fig. 1). In this case,
the degree of bismuth(III) precipitation is 99.4%.
The decrease in the degree of bismuth(III) precipita-
tion at n > 1 is due to the formation of bromide com-
plexes of the type BiBrx3
x
in solution [11], which
Fig. 1. Degree R of bismuth(III) precipitation from a ni-
trate solution vs. the molar ratio n between bromide ions
and bismuth(III) in the system. Process temperature ( C):
hinders bismuth precipitation in the form of oxo-
bromide. It can also be seen in Fig. 1 that raising
the process temperature has virtually no effect on
(
1) 22 and (2) 90.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 12 2007

PRECIPITATION OF BISMUTH(III) OXOBROMIDE FROM BROMIDE MEDIA
the degree of bismuth(III) recovery into a precipitate.
2017
It should be noted that solutions of both hydrobromic
acid and ammonium bromide can be used for quanti-
tative precipitation of bismuth(III). With ammonium
bromide used as a donor of bromide ions, the degree
of bismuth recovery into the precipitate somewhat
increases to become 99.6% at n = 1.0.
Bismuth oxobromide has clearly pronounced dif-
fraction peaks at d 8.10, 4.05, 3.52, 2.82, 2.77, 1.96,
and 1.61
(Fig. 2) [12]. It follows from the results
of X-ray studies that, in bismuth precipitation from
nitrate solutions to which bromide ions were added,
the positions of these peaks remain virtually un-
changed, irrespective of the nature of the solutions
used (Fig. 2, curve 1). This confirms that bismuth
precipitates from these solutions as the oxobromide
BiOBr in the pH range under study (0 3). X-ray
studies also demonstrate that bismuth(III) precipita-
tion from bromide solutions upon addition of water
to these solutions depends both on the process tem-
perature and on the order in which reagents are in-
troduced. At a process temperature of 22 C and addi-
tion of a bismuth bromide solution to water, the X-
ray pattern of the product corresponds to bismuth
oxobromide (Fig. 2, curve 2). If, however, water is
added to a bismuth bromide solution (Fig. 2, curve 3)
or the process is performed at an elevated temperature
Fig. 2. X-ray diffraction patterns of bismuth oxobromides
obtained by precipitation from (1) nitrate solutions and
(2 4) bromide solutions, with (2, 4) a bismuth solution
added to water and (3) water added to a bismuth solution.
(
(
I) Intensity and (2 ) Bragg angle. Temperature ( C):
1) 65, (2) 22, and (4) 90.
(
90 C) (Fig. 2, curve 4), an additional reflection ap-
pears in the X-ray diffraction patterns at d = 6.32
.
As a result of washing of these products with water,
this reflection disappears. An analysis demonstrated
that the washing solution contains hydrogen ions and
bromide ions. This indicates that, in bismuth precip-
itation from bromide solutions (ratio between bro-
mide ions and bismuth equal to 3.8), the product can
capture hydrobromic acid, which can be removed in
the stage of product washing with water.
DTA and TG data for bismuth oxobromide samples
obtained by processing of nitrate solutions (Fig. 3a)
indicate that the product is stable in a wide tempera-
ture range. On heating of bismuth oxobromide, the loss
of mass begins at temperatures higher than 600 C,
which is due to sublimation of bismuth in the form of
bromide to give oxobromides with a Bi : Br molar
ratio exceeding unity [13]. In the case of samples ob-
tained by bismuth precipitation from bromide solu-
tions (Fig. 3b), the loss of mass begins at 250 C and
is complete at 300 C. In this case, the loss of mass
is 6.3% for a product obtained upon addition of water
to a bismuth-containing solution at a process temper-
ature of 22 C and 2.7% in the case of a reverse order
of addition of the reagents. When synthesis is per-
formed at 90 C, the loss of mass by the product upon
Fig. 3. Thermograms of bismuth oxobromides obtained
by precipitation from (a) nitrate and (b) bromide solutions
and (c) of bismuth oxobromide formed by thermal treat-
ment of the product at 300 C. Sample mass 300 mg.
( m) Loss of mass and ( ) time.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 12 2007

2018
NOVOKRESHCHENOVA et al.
calcination is 6.7% in both cases. A chemical anal-
ysis of a product calcined at 300 C and kept in air
for 10 days demonstrated that this product is pure
bismuth oxobromide (its thermogram is shown in
Fig. 3c). It should be noted here that the product ob-
tained from bromide solutions has a yellowish tint,
which disappears upon washing with water or calcina-
tion at 300 C.
oxobromide from nitrate solutions commonly used in
synthesis of bismuth compounds was analyzed. Pre-
cipitation of bismuth(III) from nitrate solutions in
the form of an oxobromide at a molar ratio between
bromide ions and bismuth equal to 1.05, as well as its
precipitation from bromide solutions, fails to provide
effective purification of bismuth to remove lead and
silver [see table, composition (III)].
Analysis of IR absorption spectra of bismuth oxo-
bromides obtained by precipitation from both nitrate
and bromide solutions, and of the same oxobromides
calcined at 300 C, shows that all these spectra contain
Precipitation of bismuth from nitrate solution
in the form of a compound of composition
[
Bi O (OH) ](NO ) 3H O enables its effective puri-
6 5 3 3 5 2
fication to remove impurity metals. This process is
used to synthesize special-purity bismuth(III) oxide
1
in the spectral range under study (400 4000 cm )
only a single band associated with symmetric stretch-
[14]. Therefore, in order to obtain high-purity bismuth
1
ing vibrations of the Bi O bond (510 cm ) of the A2u
oxobromide, it is advisable to preliminarily purify bis-
muth nitrate solutions to remove associated metals by
precipitation of bismuth in the form of an oxo hydrox-
onitrate, followed by its dissolution in nitric acid.
type.
According to the results of electron-microscopic
studies of hydrolysis products, bismuth oxobromide
produced by precipitation from nitrate and bromide
solutions has in all cases, irrespective of the order
in which reagents are poured-in, the form of aggre-
gates composed of thin-lamellar oval microcrystals
with a size of 0.3 3 m in the basal plane and a thick-
ness of about 0.1 m. On washing with water, the mor-
phology of the initial microcrystals remains virtually
unchanged. The specific surface areas of bismuth(III)
oxobromides obtained at 22 and 65 C from nitrate
In view of the aforesaid, the variant of bismuth
oxobromide synthesis by precipitation from nitrate
solutions was chosen for larger-scale tests. An ad-
ditional advantage of this process is that it yields
solutions more concentrated in terms of bismuth in
the stage of dissolution of the technical-grade oxide
and enables use of stainless steel apparatus employed
in synthesis of other bismuth compounds. Metallic
bismuth of the Vi1 brand was used in the tests.
2
1
solutions are 1.7 and 1.3 m g , respectively, and
of those formed at 22 and 90 C from bromide solu-
High-purity bismuth(III) oxobromide was syn-
thesized by its precipitation from a bismuth nitrate
solution upon addition of a hydrobromic acid solu-
tion at a molar ratio between bromide ions and bis-
muth equal to 1.05 and a process temperature of
65 C. The precipitate was twice washed with distilled
water at 65 C and dried at 100 C. The tests yielded
bismuth(III) oxobromide containing (%) 68.54 bis-
2
1
tions, 1.9 and 1.2 m g . The order of introduction
of the reagents has virtually no effect on the specific
surface area of the product. In the case of washing
with water of a bismuth oxobromide having a specific
2
1
2
1
surface area of 1.2 m g , it increases to 3.0 m g ,
2
1
and upon calcination at 300 C, decreases to 1.0 m g .
A product with a specific surface area of 23 m g
2
1
3
was obtained by bismuth precipitation from dilute
muth, 26.21 bromide ions, and less than 1 10
[
20 g l 1 Bi(III)] bromide solutions.
nitrate ions. The contents of impurity metals in prod-
uct (IV) are listed in the table. The degree of bismuth
recovery from the technical-grade oxide into oxo-
bromide is 90.3%.
In order to synthesize bismuth(III) oxobromide of
increased purity, the possibility of its purification to
remove basic impurity metals in precipitation from
bromide media was assessed. A processing of bis-
muth-containing bromide solutions diluted with water
CONCLUSIONS
(
1 : 9) at a process temperature of 65 C, with the sub-
sequent washing of the precipitate with water at 65
C and drying of the product at 100 C, yielded bis-
(
1) Bismuth(III) is virtually completely precipi-
tated as an oxobromide of composition BiOBr from
bromide solutions upon their dilution with water and
from nitrate solutions upon addition of bromide ions.
5
muth(III) oxobromide whose composition (II) is listed
in the table. The results of an analysis of the product
obtained indicate that processing of bismuth-contain-
ing bromide solutions does not involve effective puri-
fication of bismuth to remove lead, silver, and iron.
In this context, the possibility of obtaining bismuth
(2) The product obtained in processing of bromide
solutions may contain hydrobromic acid, which is
removed by washing of the product with water or its
calcination at 300 C.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 12 2007

PRECIPITATION OF BISMUTH(III) OXOBROMIDE FROM BROMIDE MEDIA
3) To obtain high-purity bismuth oxobromide from 6. USSR Inventor’s Certificate, no. 1116011.
2019
(
technical-grade products, it is necessary to preliminarily
purify bismuth to remove associated metals by its pre-
cipitation from nitrate solutions in the form of a com-
7
. Karyakin, Yu.V. and Angelov, I.I., Chistye khimi-
cheskie veshchestva (Pure Chemical Substances),
Moscow: Khimiya, 1974.
pound of composition [Bi O (OH) ](NO ) 3H O.
6
5
3
3 5
2
8. Yukhin, Yu.M., Daminova, T.V., and Smirnov, V.I.,
Khim. Interesakh Ustoich. Razv., 1999, vol. 7,
pp. 745 749.
REFERENCES
9
. Aleksandrova, T.P. and Kletenik, Yu.B., Zh. Anal.
Khim., 1994, vol. 49, pp. 615 619.
1
2
. Polyvyannyi, I.R., Ablanov, A.D., and Batyrbeko-
va, S.A., Vismut (Bismuth), Alma-Ata: Nauka, 1989.
1
1
0. Kletenik, Yu.B., Tarasova, V.A., and Bek, R.Yu.,
. Yukhin, Yu.M. and Mikhailov, Yu.I., Khimiya vis-
mutovykh soedinenii i materialov (Chemistry of Bis-
muth Compounds and Materials), Novosibirsk: Sib.
Otd. Ross. Akad. Nauk, 2001.
Zh. Anal. Khim., 1987, vol. 42, pp. 891 896.
1. Fedorov, V.A., Kalosh, T.N., Shmyd’ko, L.I., and
Mironov, V.E., Zh. Neorg. Khim., 1972, vol. 17, no. 8,
pp. 2089 2095.
3
4
5
. Dolgikh, V.A., Kholodkovskaya, L.N., and Popov-
kin, B.A., Zh. Neorg. Khim., 1996, vol. 41, no. 6,
pp. 970 975.
1
2. JCPDS-International Center for Diffraction Data, 1995.
13. Nurgaliev, B.Z., Popovkin, B.A., and Stefano-
vich, S.Yu., Zh. Neorg. Khim., 1983, vol. 28,
pp. 2207 2211.
. Handbuch der praparativen anorganischen Chemie,
Bd. 3, von Brauer, G., Huber, F. et al., Eds., Stuttgart:
Ferdinand, 1981.
1
4. Yukhin, Yu.M., Mikhailov, Yu.I., Afonina, L.I., and
Podkopaev, O.A., Vysokochist. Veshch., 1996, no. 4,
pp. 62 71.
. Gmelins Handbuch der anorganischen Chemie, 8
Auflage, Wismut, Weinheim Bergstr: Chemie, 1964.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 12 2007