A study of a catalyst based on oxides of base transition metals for decomposition of ozone and oxidation of toxic organic compounds

Article abstract of DOI:10.1134/S1070427207080174

Cement-containing GTT catalysts based on manganese, copper, and nickel oxides were developed and introduced into practice in processes employing ozone technologies and in oxidation of toxic organic compounds. Physicochemical methods were used to study the process of catalyst formation and the influence exerted by various brands of manganese salts and by preparation conditions and, in particular, calcination temperatures and grain molding technique on the characteristics of the catalytic systems obtained. Several commercial batches of GTT catalysts were manufactured.

Full text of DOI:10.1134/S1070427207080174

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 8, pp. 1353 1359.
Pleiades Publishing, Ltd., 2007.
Original Russian Text S.N. Tkachenko, E.Z. Golozman, V.V. Lunin, I.V. Kozlova, G.V. Egorova, E.A. Boevskaya, I.S. Tkachenko, A.I. Nechugovskii,
M.P. Yaroshenko, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 8, pp. 1314 1320.
CATALYSIS
A Study of a Catalyst Based on Oxides of Base
Transition Metals for Decomposition of Ozone
and Oxidation of Toxic Organic Compounds
S. N. Tkachenko, E. Z. Golozman, V. V. Lunin, I. V. Kozlova, G. V. Egorova,
1
E. A. Boevskaya, I. S. Tkachenko, A. I. Nechugovskii, and M. P. Yaroshenko
Lomonosov State University, Moscow, Russia
Novomoskovsk Institute of Nitrogen Industry, Open Joint-Stock Company, Novomoskovsk,
Tula oblast, Russia
TIMIS Research-and-Promotion Firm, Limited Liability Company, Moscow, Russia
Received August 29, 2006; in final form, March 2007
Abstract Cement-containing GTT catalysts based on manganese, copper, and nickel oxides were developed
and introduced into practice in processes employing ozone technologies and in oxidation of toxic organic
compounds. Physicochemical methods were used to study the process of catalyst formation and the influence
exerted by various brands of manganese salts and by preparation conditions and, in particular, calcination
temperatures and grain molding technique on the characteristics of the catalytic systems obtained. Several
commercial batches of GTT catalysts were manufactured.
DOI: 10.1134/S1070427207080174
At present, one of the most efficient and ecolog-
ically safe ways to purify drinking water, wastewater,
and water in swimming pools is ozonation. The use of
ozone is due to its oxidizing and bactericidal prop-
efficiency under humid conditions, contain noble me-
tals and, in particular, silver and are rather expensive.
Catalysts composed of oxides of nonprecious tran-
sition metals and exhibiting stable operation under
various conditions have been created by developing
cement-containing catalysts of GTT and GT brands,
based on manganese, copper, and nickel oxides [5 9].
The activity of these catalysts in a dry flow is close
to that of hopcalite and exceeds it by a factor of 1.5 2
in operation in a humid flow. These catalytic systems
have high mechanical strength and water resistance,
and their grains preserve shape when brought in con-
tact with water. In a dry gas flow, the catalysts work
at room temperature. In a humid flow, the working
temperature range is 20 120 C. In case of a decrease
in activity in a corrosive humid medium, the catalysts
can be regenerated at 250 300 C in 2 3 h.
erties; however, the acrid smell and toxicity of ozone
3
(
MPC = 3.3 g m ) makes topical the problem of
destruction of residual ozone [1]. Photochemical, ther-
mal, and catalytic methods of ozone decomposition
are possible. The optimal in economical efficiency
and simplicity of technological apparatus is the cat-
alytic decomposition of ozone [2].
The industrially employed catalyst for ozone de-
composition, hopcalite, is composed of 60% manga-
nese oxide, 25% copper oxide, and 15% binder (ben-
tonite clay). It has an important disadvantage, poor
mechanical strength, to the point of grain disintegra-
tion under the action of moisture drops [3]. The known
catalysts [4], distinguished by stability and operation
Tests demonstrated that GTT is efficient not only
in ozone decomposition, but also in oxidation of
carbon monoxide, methane, benzene, styrene, iso-
propylbenzene, butyl acetate, and other compounds.
The GTT catalyst possesses the necessary developed
surface, thermal stability, and resistance to coking in
1
N.I. Murashov, Zh.V. Myasnikova, S.G. Dormidontova, and
L.D. Kvasova took part in catalyst preparation on laboratory,
pilot, and industrial installations, and also in catalytic activity
tests and determination of other characteristics of catalysts.
1353

1
354
Table 1. Basic characteristics of the cement-containing GTT catalyst (for extrudates)
Parameter Grains of dark brown to black color
TKACHENKO et al.
3
Bulk density, kg dm , no more than
1.3
1
Mechanical strength, kg mm grain diameter, no less than:
average
minimum
1.1
0.6
Porosity , %, no less than
40
100
2
1
Specific surface area S , m g , no less than
sp
*
Ozone decomposition factor
in a gas flow, no less than:
dry gas flow
humid gas flow
1.1 10 4
0.55 10 4
*
The quantity , the fraction of active, i.e., leading to decomposition, collisions of ozone molecules with the catalyst surface, is
taken as a measure of the catalyst activity. The ozone decomposition factor is given by the Lunin Popovich Tkachenko formula
[
3] = 4w[ln(c /c)]V S, where c and c are the ozone concentrations at the reactor inlet and outlet, respectively; w, volumetric
0 t 0
gas flow rate; V , thermal motion velocity of molecules; and S, total external surface area of catalyst grains. The parameter is
t
proportional to the effective rate constant of the heterogeneous decomposition of ozone.
oxidation of the chemical products mentioned above.
The basic technical characteristics of GTT are listed in
Table 1.
samples prepared by compaction with KBr. The spe-
cific surface area of catalyst samples was determined
by the low-temperature adsorption technique (BET).
The total porosity was found from the true and ap-
parent densities. The apparent density was calculated
by dividing the mass of a sample by its geometric
volume. The true density was determined by pycnom-
etry, from the volume of toluene absorbed by a sam-
ple. The error in determining the total porosity was
The technology of GTT fabrication has been im-
plemented at the catalyst shop of NIAP. The catalyst
is manufactured as compacted pellets d h = 6
3
2
(5
3) mm and in the extruded form [extrudates with
a diameter of 1.5 to 5 mm and length of 5 to 15 mm;
2
pellets with d h = 5 3 (4 3) mm ].
5
%.
The aim of this study was to examine, using a set
of physicochemical techniques, the influence exerted
by the preparation conditions and composition of
the starting manganese-containing concentrate on
the formation of the Mn Cu Ni Al Ca system and
to determine the relationship between the phase com-
position of the catalyst and its catalytic activity in
decomposition of ozone and oxidation of benzene.
An X-ray phase analysis (XPA) demonstrated that
the synthesis of the catalyst involves, in stages
of molding, humid-air treatment, HTT, and drying,
the reaction of interaction (heterogeneous ion ex-
change) between hydroxocarbonates of copper (CHC)
and nickel (NHC) and calcium aluminates (talum: CA,
2
CA ) to give hydroxo aluminates (HA) of nickel
2
and copper and calcite CaCO [12]. XPA does not
3
reveal any interaction of the starting MnCO with
EXPERIMENTAL
3
the above components, whereas IR spectroscopy in-
dicates [13] that a certain amount of manganese ions
can be incorporated into the lattice of gibbsite formed
as a result of talum hydration.
The catalyst was fabricated by the method of hy-
drothermal synthesis (HTS) [10, 11], which includes
mixing of the starting components in the presence
of aqueous ammonia and granulation of the resulting
paste, followed by keeping of the grains first in
a humid-air medium and then in hot water in the stage
of hydrothermal treatment (HTT). After that the cat-
alyst is dried and calcined.
The temperature at which a catalyst is calcined
strongly affects its formation and catalytic activity.
For GTT samples calcined at 100 800 C, the phase
composition and catalytic activity in ozone decompo-
sition and benzene oxidation were determined. At low
calcination temperatures (100 200 C), the starting
An X-ray diffraction analysis was carried out on
a DRON-3 diffractometer (graphite monochromator,
CuK radiation, reflected beam). IR spectra were
measured on a Specord 75-IR spectrophotometer, with
2
CA, CA are designations used in cement chemistry: CA =
2
CaO Al O and CA = CaO 2Al O .
2
3
2
2 3
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 8 2007

A STUDY OF A CATALYST BASED ON OXIDES OF BASE TRANSITION METALS
1355
metal hydroxocarbonates and products of talum hydra-
tion and ion exchange are present. At higher tempera-
tures, metal hydroxocarbonates decompose to the re-
spective oxides. The starting manganese-containing
component decomposes to oxides of various composi-
tions. In the temperature range 300 350 C, a phase
Table 2. Phase composition of the manganese-containing
stock at calcination temperatures of 200 800 C
Phase composition
T,
C
no. 1 MnCO3
no. 2 MnCO3 no. 3 MnCO3
(supply from
Sedema
close in X-ray diffraction characteristics to MnO2
appears in the sample composition, the intensity of
Russia)
supply from Belgium
Mn O -related peaks increases, and the Mn O phase
2
3
3
4
is weakly pronounced. At temperatures of 350
00 C, the content of Mn O increases, that of Mn O
3
2
00 MnCO , Mn O
MnCO3
MnCO3
3
2 3
6
3
4
2
3
00 MnCO , Mn O , MnCO , MnO , MnCO , Mn O
3
2
3
3
2
3
3
4
3
decreases, and MnO2 disappears. At 700 800 C
the main manganese containing phase in Mn O .
Mn O , MnO
Mn O , Mn O
3
4
2
3 4 2 3
3
4
4
00 Mn O , Mn O
Mn O , Mn O Mn O , MnCO
2 3 3 4 3 4
2
3
3
4
Samples calcined in the temperature range 300
500 Mn O , Mn O
Mn O , Mn O Mn O , Mn O
2
3
3
4
4
4
2 3 3 4 2 3 3 4
6
00 C show an ozone decomposition factor of no
600 Mn O , Mn O
Mn O , Mn O Mn O , Mn O
2 3 3 4 2 3 3
2
3
3
4
4
4
7
8
00 Mn O , Mn O
Mn O , Mn O Mn O , Mn O
less than 1.5 10 (Fig. 1). Samples calcined at
2
3
3
2
3
4
3
4
2
3
4
3
3
00 Mn O4
Mn O
3
Mn O
3
4
00 600 C exhibited the highest activity in ozone
4
decomposition [ = (2.38 2.45) 10 ], and those
calcined at 300 400 C, in benzene oxidation, with
the temperature of benzene oxidation at 50% con-
version equal to 230 240 C (Fig. 1). The decrease in
the catalytic activity at calcination temperatures higher
than 600 C is presumably due to recrystallization of
the NiO and CuO phases. In accordance with this
circumstance, the optimal temperature of catalyst cal-
cination was chosen to be 350 400 C for ozone de-
composition and 300 350 C for benzene oxidation.
that of the starting MnCO , although some distinc-
3
tions are observed. At 300 C, the MnO phase ap-
2
pears in all the three samples. This phase is more
pronounced in sample no. 2; further, at 350 500 C,
The catalyst was prepared from different batches
of a Mn-containing stock (Table 2) supplied under the
brand Manganese hydroxocarbonate, which, according
to XPA and IR spectral data, is anhydrous manganese
carbonate, occasionally containing the Mn O phase.
2
3
For example, the IR spectrum of sample no. 1 con-
Fig. 1. Activity of the GTT catalyst in ozone decomposition
tains, together with absorption bands at 1420 1440,
and benzene oxidation vs. calcination temperature T
.
calc
1
8
70, and 730 cm , which characterize the carbonate
( ) Ozone decomposition temperature and (T ) tempera-
ox
anion in the composition of manganese carbonate, also
ture of 50% oxidation of benzene. (1) Ozone decomposition
factor and (2) benzene oxidation temperature.
1
strong absorption bands at 580 530 cm , related to
the presence of an oxide phase (Fig. 2). According to
XPA data, this is Mn O . The study revealed that no
2
3
MnCO decomposition is observed up to 200 C; and
3
at 300 C manganese oxides Mn O and MnO appear,
3
4
2
together with MnCO and Mn O , in stock sample
3
2
3
nos. 1 and 2 and only Mn O in sample no. 3.
3
4
The MnO phase was not found in any of the stock
2
samples at 400 C, and in the range 400 800 C Mn O3
2
is gradually converted to Mn O , which becomes
3
4
the main manganese-containing phase at 800 C.
The above-mentioned brands of MnCO were used
3
to prepare GTT catalyst samples under laboratory
conditions. XPA data for GTT catalyst samples cal-
cined at 300 500 C are listed in Table 3. The decom-
Fig. 2. IR spectra of uncalcined MnCO samples. (A) Ab-
sorption and ( ) wave number. Supply source: (1) Sedema,
Belgium; (2) Belgium; and (3) Russia.
3
position of MnCO in the catalyst occurs similarly to
3
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 8 2007

1356
TKACHENKO et al.
Table 3. Phase composition of GTT samples (based on various brands of MnCO ) calcined at 300 500 C
3
Phase composition
T, C
no. 1 MnCO3 Sedema
supply from Belgium
no. 2 MnCO3
no. 3 MnCO (supply from Russia)
3
3
3
4
4
5
00 Mn O , MnO , CA , CaCO ,
MnO , CaCO , CA , MnCO , NiO,
MnCO , MnO , CaCO , CA , NiO,
2
3
2
2
3
2
3
2
3
3
2
3
2
MnCO , NiO, CuO
CuO
Mn O , CaCO , Mn O , MnO ,
CuO
MnO , MnCO , CaCO , CA ,
3
50 Mn O , Mn O , CaCO , CA ,
2
3
3
4
3
2
2
3
4
3
2
3
2
2
3
3
2
MnCO , NiO, CuO
CA , MnCO , NiO, CuO
Mn O , NiO, CuO
3
2
3
2 3
00 Mn O , Mn O , CaCO , CA
Mn O , Mn O , CaCO , MnO ,
Mn O , CaCO , Mn O , CA , NiO,
2
3
3
4
3
2
3
3
4
3
2
3
4
3
2
3
2
CA , NiO, CuO
CuO
2
50 Mn O , CaCO , Mn O , CA , NiO, Mn O , Mn O , CaCO , CA , NiO, Mn O , Mn O , CaCO , CA , NiO,
2
3
3
3
4
2
2
3
3
4
3
2
3
4
2
3
3
2
CuO
CuO
CuO
00 Mn O , Mn O , CA , CaCO , NiO, Mn O , Mn O , CaCO , CA , NiO, Mn O , Mn O , CaCO , CA , NiO,
2
3
3
4
2
3
2
3
3
4
3
2
2
3
3
4
3
2
CuO
CuO
CuO
Table 4. Physicochemical characteristics and catalytic activity of GTT samples calcined at T = 400 C
Chemical composition:
active components, %
Tbenz.ox
at 50% conversion
,
C,
S ,
m g
sp
GTT catalyst
, %
2
1
no. 1 MnCO3 Sedema,
supplied from Belgium
Mn O , 29.3, CuO, 19.6,
1.88 10 4
1.85 10 4
1.85 10 4
250
220
230
100
100
100
70
50
60
3
4
NiO, 10.1;
= 59
no. 2 MnCO , supplied
Mn O , 28.6, CuO, 21.2,
3
3 4
from Belgium
NiO, 10.3;
= 60.1
no. 3 MnCO , supplied
Mn O , 29.6, CuO, 20.6,
3
3 4
from Russia
NiO, 10.9;
= 61.1
4
the content of this phase decreases and that of the ox-
ides Mn O and Mn O increases, whereas in sample
in ozone decomposition, = (1.81 1.88) 10 . Con-
sequently, presence of the Mn O phase in the starting
2
3
3
4
2
3
no. 3, mostly the content of the Mn O phase grows.
manganese-containing component does not exert any
significant influence on the GTT activity in ozone
decomposition. However, a minor decrease in activity
is observed in benzene oxidation: the difference in
benzene oxidation temperature at 50% conversion is
3
4
Also, the degree of crystallinity of the copper oxide
phase is higher at these temperature than that of nickel
oxide. This is due to the fact that mostly the nickel
hydroxoaluminate phase is formed in the preceding
stages, and especially in the HTT stage, and this leads
to formation of a dispersed phase of nickel oxide in
calcination.
20 30 C.
Extrudates were prepared on a pilot apparatus from
MnCO of Sedema brand, supplied from Belgium,
3
Table 4 lists physicochemical parameters of sam-
ples calcined at T = 400 C. The total amount of
the active component in samples of a finished catalyst
is 59 to 61%. The specific surface areas of the sam-
and MnCO from Russia. The ozone decomposition
3
factor for batch no. 1 (extrudates 1.5 mm in diameter),
synthesized from MnCO containing an admixture of
3
Mn O is 1.13 1.25 times lower than that for batch
2
1
2
3
ples are virtually the same ( 100 m g ). The highest
porosity ( 70%) is observed for GTT sample no. 1.
no. 2 (extrudates 1.5 mm in diameter), produced from
MnCO of domestic manufacture, in which the Mn O
3
2
3
Activity tests of samples prepared from different
stock batches demonstrated that, at close compositions
and surface areas, all the samples exhibit high activity
phase is either absent or present in a minor amount.
GTT no. 1 is inferior to GTT no. 2 in specific surface
area, porosity, and total amount of the active com-
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 8 2007

A STUDY OF A CATALYST BASED ON OXIDES OF BASE TRANSITION METALS
1357
Table 5. Physicochemical characteristics and catalytic activity of laboratory-pilot batches of extrudates and molded GTT
pellets calcined at T = 415 15 C
XPA data
for finished cat-
alyst, 415 15 C
Tbenz.ox, C
at 50%
conversion
Chemical com-
position: active
components, %
S ,
,
%
sp
GTT catalyst
2
1
m g
No. 1, extrudates,
d = 0.15 cm, based on CuO, Mn O , CA
MnCO3 Sedema,
supplied from Belgium
No. 2, extrudates,
d = 0.15 cm, based on CA , boehmite
Mn O , NiO, CaCO ,
2.45 10 4
240
250
260
260
220
110
120
120
90
40 Mn O , 28.9,
3 4
3
4
3
CuO, 18.5,
NiO, 11.3;
2
3
2
= 58.6
Mn O , CaO , NiO, CuO, (2.7 3) 10 4
10 Mn O , 29.2,
3
4
3
3 4
CuO, 21.6,
NiO, 10.7;
2
MnCO , supplied from
3
Russia
No. 3, extrudates,
d = 0.25 cm, based on CuO, CA2
= 61.5
Mn O , CaCO , NiO,
2.2 10 4
(2.1 2.2) 10 4
1.58 10 4
60 Mn O , 30.2,
2
4
3
3 4
CuO, 20.4,
NiO, 11.3;
MnCO , supplied from
3
Russia
No. 4, extrudates,
d = 0.30 cm, based on MnCO , NiO, CuO
= 61.9
Mn O , CaCO , CA ,
60 Mn O , 28.0,
3
4
3
2
3 4
CuO, 22.7,
NiO, 10.4;
3
MnCO , supplied from
3
Russia
No. 5, molded pellets,
d h = 5 3 mm,
= 61.1
CuO, MnO2,
Mn O , trace amounts
110
40 Mn O , 30.3,
3
4
CuO, 20.2,
NiO, 9.0;
= 59.5
3
4
November 2004, based
CA , NiO, CaCO ,
2 3
on MnCO , supplied
aragonite, MnCO3
3
from Belgium
No. 6, molded pellets,
d h = 5 3 mm, June
CuO, MnO , MnCO ,
1.90 10 4
2.35 10 4
220
230
100
110
60 Mn O , 26.5,
2
3
3 4
Mn O , CA , CA, NiO,
CuO, 20.5,
NiO, 9.5;
3
4
2
2
005, based on MnCO3, CaCO , trace amounts
3
supplied from Belgium
No. 7, molded pellets,
d h = 5 3 mm, June
= 56.5
CuO, Mn O ,
70 Mn O , 27.1,
3
4
3 4
MnO , MnCO , CA ,
CuO, 20.5,
NiO, 9.0;
= 56.6
2
3
2
2
005, based on MnCO3, CaCO , NiO, aragonite,
3
supplied from Bulgaria
trace amounts, CA
ponent (Table 5), which can also account for the de-
crease in . The catalytic activities of these batches
in benzene oxidation do not differ significantly.
of GTT in ozone decomposition in the case of in-
dustrial batches. It can be seen from the data presented
that there is difference in porosities (by a factor of
1
.17 1.5) even for batches prepared from the same
Molded pellets were produced on industrial equip-
ment (FP-025 pellet-granulator, manufactured by
Dzerzhinsk NIIkhimmash federal state unitary enter-
prise) from manganese carbonate from Belgium, which
contains an insignificant amount of Mn O (GTT cat-
brand of raw material, manganese carbonate manu-
factured in Belgium. The catalytic activities of these
batches in benzene oxidation do not differ signif-
icantly.
2
3
alyst batch nos. 5 and 6), and manganese carbonate
A comparison of the basic characteristics of GTT
batches produced under pilot-industrial conditions
(extrudates of various diameters) and manufactured
under industrial conditions (molded pellets) at
the same calcination temperature demonstrated that
that the activity of extrudates in ozone decomposition
exceeds that of molded pellets by, on average, a factor
manufactured in Bulgaria, which contains no Mn O3
2
(
catalyst batch no. 7) (Table 5). It was found that
the ozone decomposition factor for GTT no. 7 is,
on average, 1.4 times that for GTT nos. 5 and 6. It
is, however, impossible to state unambiguously that
the brand of MnCO affects the catalytic activity
3
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 8 2007

1358
TKACHENKO et al.
of 1.1 1.7 and that in benzene oxidation is lower
benzene oxidation temperature at 50% conversion
sion: 210 230, 220 230, and 220 230 C, respec-
tively.
(
is, on average, 30 40 C higher) (Table 5). These
batches show insignificant differences in porosity,
specific surface area, and amount of the active com-
ponent. It can be assumed that the changes in activity
are due to specific features of the decomposition of
the starting manganese carbonates in the extrudates
and pellets in the calcination stage. It has been found
previously that the type of a manganese-containing
phase formed is sensitive to the calcination tempera-
Laboratory samples were produced with manganese
carbonates containing 0.008 and 0.7% sulfates.
The mass fraction of sulfates in the finished catalyst
was 0.004 and 0.12%, respectively. The samples ex-
hibited virtually the same activity in ozone decom-
position: = (1.9 0.2) 10 . The benzene oxida-
tion temperature at 50% conversion was 220 and
4
240 C.
ture. In the range T = 300 350 C, the MnO phase is
It can be seen from these data that the mass frac-
2
formed in extrudates (Table 3), with the benzene ox-
tion of sulfur in terms of sulfides in the starting man-
ganese-containing component has no effect on the cat-
alytic activity of the GTT catalyst in both ozone de-
composition and benzene oxidation. It is known that
a requirement to the purity of starting components
affects their cost. Consequently, less expensive raw
materials can be used in GTT manufacture. Industrial
batches of the catalysts developed have been manu-
factured to order of TIMIS Research-and-Promotion
Firm, Limited Liability Company at Novomoskovsk
Institute of nitrogen industries and successfully work
in ozonizer installations at more than 40 plants of
Russia, Ukraine, Thailand, and Switzerland [14 16].
idation temperature at 50% conversion equal to 230 C
4
(
Fig. 1) and = (2.22 2.38) 10 . In the range T =
4
00 450 C, Mn O is the main manganese-contain-
3
4
ing phase, with T
= 240 280 C and = 2.45
benz.ox
4
1
0 . In molded pellets, the MnO phase is still pres-
2
ent at T = 400 430 C, the benzene oxidation tem-
perature at 50% conversion is 220 230 C, and
=
4
(
1.58 2.35) 10 (Table 5). Presumably, the pre-
dominance of the manganese-containing phase Mn O4
3
in GTT samples (extrudates, pellets) at calcination
temperatures in the range 300 450 C favors an in-
crease in the activity of the catalyst in ozone decom-
position, and the presence of the MnO phase pos-
itively affects the activity in benzene oxidation.
2
GTT catalysts are also effectively used in gas-
convectors of the gas-discharge type, intended for
purification of ventilation gases and recycled and
influent air to remove toxic substances, such as butan-
ol, styrene, toluene, phenol, benzene, formaldehyde,
aniline, etc., formed in operation of motor transport,
technological equipment, and public feeding facilities.
Air is purified in a gas-convector under the action of
an electric discharge on molecule of gases present in
the discharge zone.
According to the quality regulations for manganese-
containing raw materials, the mass fraction of sul-
fur in terms of sulfates should not exceed 0.04%.
The content of sulfur in the manganese-containing
starting component, especially of domestic or Bul-
garian manufacture, fails to satisfy these requirements.
A number of test batches were prepared in the form of
extrudates based on manganese carbonates containing
2
4
0
.16 to 0.23% sulfates (SO ). In the finished cat-
alyst, the content of sulfates varied from 0.08 to
.11%. In this case, the ozone decomposition factor
was = (2.1 2.7) 10 , which points to a high ac-
tivity of the catalyst. Also, the benzene oxidation
temperature at 50% conversion was found to be 240
CONCLUSIONS
0
4
(1) An integrated study of the process in which
catalysts for ozone decomposition are formed from
copper and nickel hydroxocarbonates, manganese car-
bonate, and calcium aluminates (talum) demonstrated
that a heterogeneous ion exchange occurs between
the components in the course of preparation, to give
precursors of the active phase.
2
60 C for this catalyst.
When preparing molded pellets, manganese car-
bonates containing 0.0076 0.026, 0.56 0.69, and
.77 1.14% sulfates were used. The mass fractions of
0
2
SO4 in the finished catalysts were 0.0065 0.025,
.032 0.15, and 0.197 0.36%, respectively. In this
case, the ozone decomposition factors are (1.35 1.85)
(2) It was shown that presence of the manganese-
containing phase Mn O in GTT samples (extrudates,
0
3
4
pellets) favors, at calcination temperatures of 300
450 C, an increase in the catalytic activity in ozone
4
4
4
1
0 , (1.85 2.4) 10 , and (2.0 2.4) 10 , respec-
tively, which corresponds to a high catalytic activity
in ozone decomposition. The catalytic activities of
these batches in benzene oxidation were evaluated
by the benzene oxidation temperature at 50% conver-
decomposition, and presence of the MnO phase pos-
2
itively affects the activity in benzene oxidation.
The optimal GTT calcination temperatures for ozone
decomposition and benzene oxidation were determined.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 8 2007

A STUDY OF A CATALYST BASED ON OXIDES OF BASE TRANSITION METALS
3) It was demonstrated that the catalytic activity 6. USSR Inventor’s Certificate, no. 1768274.
1359
(
of the GTT catalyst in both ozone decomposition and
benzene oxidation is not affected to any significant
extent by the composition of the manganese-contain-
ing raw material and by the amount of sulfur (in
the concentration range studied) in the starting com-
ponents.
7
. Makhov, E.A., Tkachenko, S.N., Golosman, E.Z.,
et al., Khim. Prom st. Segodnya, 2003, no. 7, p. 11.
. Yakerson, V.I. and Golosman, E.Z., Katalizatory i
tsementy (Catalysts and Cements), Moscow: Khimiya,
1992.
8
9
. Tkachenko, S.N., Lunin, V.V., Egorova, G.V., et al.,
The Int. Ozone Association: 17th world congress (IOA
(
4) Extrudates with a diameter of 1.5 5 mm and
1
7), Ozone and Related Oxidants, Innovative and
Current Technologies, Strasbourg, France, August
2 25, 2005, p. 50.
length of 5 15 mm and molded pellets [(d h =
2
5
3 (4 3) mm ] were produced. The catalyst ob-
2
tained exhibits high activity and mechanical strength
in operation in both dry and humid gases.
1
1
0. Golosman, E.Z., Kinet. Kataliz, 2001, vol. 42, no. 3,
pp. 383 393.
1. Golosman, E.Z. and Yakerson, V.I., Proizvodstvo i
ekspluatatsiya promyshlennykh tsementsoderzhashchikh
katalizatorov (Manufacture and Use of Industrial
Cement-containing Catalysts), Available from
NIITEKhIM, 1992, Cherkassy, no. 287-khp-92.
2. Nechugovskii, A.I., Grechenko, A.N., and Golos-
man, E.Z., Zh. Prikl. Khim., 1990, vol. 63, no. 8,
pp. 1747 1751.
3. Troshina, V.A., Mamaeva, I.A., Salomatin, G.I., et al.,
Zh. Prikl. Khim., 2003, vol. 76, no. 3, pp. 430 436.
14. RF Patent 2163836.
15. Demidyuk, V.I., Tkachenko, S.N., Makhov, E.A.,
et al., Kataliz Prom sti, 2003, no. 6, pp. 42 46.
6. Tkachenko, S.N., Demidyuk, V.I., Egorova, G.V.,
REFERENCES
1
2
. Rodionov, A.I., Klushin, V.N., and Torocheshni-
kov, N.S., Tekhnika zashchity okruzhayushchei sredy
(
Environment Protection Technology), Moscow: Khi-
1
1
miya, 1989.
. Tkachenko, S.N., Homogeneous and Heterogeneous
Decomposition of Ozone, Doctoral Dissertation,
Moscow, 2004.
3
4
. Tkachenko, S.N., Golosman, E.Z., and Lunin, V.V.,
Kataliz Prom sti, 2001, no. 2, p. 52.
. Lunin, V.V., Popovich, M.P., and Tkachenko, S.N.,
Fizicheskaya khimiya ozona (Physical Chemistry of
Ozone), Moscow: Mosk. Gos. Univ., 1998.
1
5
. RF Patent 2077946.
et al., Khim. Prom st., 1992, no. 10, p. 604.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 8 2007