II International Symposium on Carbon for Catalysis ABSTRACTS

OP-I-5
Ru-CeO 2 /SIBUNIT CATALYSTS FOR CATALYTIC WET AIR OXIDATION
Dobrynkin N.M., Pestunova O.P., Batygina M.V., Parmon V.N., Astrova D.A. 1 ,
Laskin B.M. 1 , Schegolev V.V. 1 , Besson M. 2 , Gallezot P. 2
Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia
1 Research Scientific Center "Applied Chemistry", St.-Petersburg, Russia
2 Institut de Recherches sur la Catalyse, Villeurbanne Cedex, France
e-mail: oxanap@catalysis.ru
The Catalytic Wet Air Oxidation (CWAO) process with oxygen at high temperatures and
pressures is suitable for the elimination of both organic and inorganic substances in various
industrial wastewaters. The main problem for this process is the design of a catalytic system
stable in aggressive oxidizing wet process conditions. Noble metal (Ru, Pt, Pd) supported on
carriers resistant to leaching such as ZrO 2 , TiO 2 , CeO 2 and carbon were shown to be stable
and active catalysts for CWAO [1-3]. However there is very strong requirement for the
economy of these processes to decrease the cost of catalysts and consequently the amount of
noble metals.
We have shown earlier that the level of activity of Ru/carbon catalysts in the oxidation of
various substances can be increased by using carrier based on graphite-like porous materials
of Sibunit family promoted with CeO 2 . It was also possible simultaneously to improve the
stability of the catalyst and to reduce the amount of Ru from 5 to 0.5% [4,5].
In this work different Ru/CeO 2 /Sibunit catalysts were tested under mild reaction conditions
(T=160 – 200 o C and P O2 =1.0 MPa) for the complete oxidation of widespread contaminants of
industrial wastewater such as phenol compounds. The optimal composition of catalyst was
found to be 0.5-0.6%Ru/4-6%CeO 2 /Sibunit-4.
Catalyst 0.6%Ru-5%CeO 2 /Sibunit was also used in a well stirred autoclave to study the
oxidation kinetics of phenol at 140-180°C. A rate law was established by carrying
experiments as a function of reaction parameters (temperature, concentration). The following
simplified mechanism of an initial stage of catalytic oxidation of phenol was suggested:
Ph+[ ] ⇔ [Ph] (1)
O 2 (gas)
⇔ O 2 (sol) (2)
O 2 (sol)+2[ ] ⇔ 2[O] (3)
[Ph]+[O] ⇔ [A]+[ ] (4)
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