1070-4272/05/7807-1106+2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 7, 2005, pp. 1106 !1109. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 7,
2005, pp. 1127!1129.
Original Russian Text Copyright + 2005 by Bubnov, Burova, Grinevich, Kuvykin.
OF CHEMISTRY AND TECHNOLOGY
Combined Plasma-Induced and
Catalytic Decomposition of Phenols
A. G. Bubnov, E. Yu. Burova, V. I. Grinevich, and N. A. Kuvykin
Ivanovo State University of Chemical Engineering, Ivanovo, Russia
Received February 9, 2005
Abstract-Decomposition of phenol and its derivatives, resorcinol and pyrocatechol, was studied in barrier-
discharge plasma in the presence of substances exhibiting catalytic properties.
Methods of high-energy chemistry find application
in water treatment and purification. In particular, the
use of barrier discharge plasma makes it possible to
improve the water quality via decreasing the concen-
trations of organic pollutants by factors of several tens
. A new line in this area is application of combined
plasma-induced and catalytic processes (CPICPs) ac-
celerating decomposition of organic compounds, i.e.,
increasing the energy efficiency of the process. When
introduced directly into the plasma zone, the catalyst
and the solution being treated are exposed to all active
species, including short-lived species that are formed
in the gas and liquid phases. Active species in plasma
can activate the catalyst at low temperatures, or active
species capable of initiating and accelerating decom-
position of organic compounds in water can be formed
on the catalyst.
In this work we studied the kinetics of transforma-
tion of phenols when exposed to active species of
barrier-discharge plasma (BDP) and in CPICP.
The experiments were run on a setup described
in . Technical-grade oxygen (99.8 vol % pure,
with nitrogen and argon as main impurities) served as
plasma-forming gas. The flow rate of O
in all the experiments (3.2 cm
). Barrier discharge
was excited from a high-voltage transformer (alternate
current with a frequency of 50 Hz); the voltage ap-
plied to the electrodes was 16 kV. As model pollu-
tants we chose phenol (PN) and its derivatives, resor-
cinol (RS) and pyrocatechol (PC), with different ini-
tial concentrations. During the studies we controlled
the content of phenol in water before and after plas-
Aqueous solutions of phenol were treated both in
the presence and absence of compounds exhibiting
catalytic properties. In the former case, prior to intro-
ducing the water being treated into the setup in the
plasma burning zone, a catalyst (a nickel-containing
compound) was preliminary applied to the hydrophilic
inert material (fiber glass) coating the central noninsu-
The catalyst was applied to the fiber glass fabric by
the following procedure. The fabric was leached with
solution (5.5 wt %) at 90oC for 10 min,
whereupon it was dried at 110oC and calcined in air
at 250oC . Next, the fiber glass fabric was placed
into an aqueous NaOH solution (pH 7311), and a
weighed portion of a salt, Ni(NO
, was added to
yield 0.2 M solution. After 40 min, the fabric was
repeatedly dried at 110oC and calcined at 250oC for
303 40 min .
The qualitative characteristics of the initial and
treated waters were estimated by the procedures
described in .
We found earlier [1, 5] that the efficiency a of
plasma-induced decomposition of organic compounds
dissolved in water depends on a multitude of param-
eters, including the time of contact of the gas and solu-
tion with the plasma zone t, specific power W contri-
buted to the discharge, and the initial concentration of
the solute c
. Our experiments showed (Fig. 1) that,
with increasing initial concentration of the phenols in
water, a tends to decrease, most profoundly in the
case of PN and least profoundly, in the case of PC.
This is also evident from Fig. 2 demonstrating the
efficiency of decomposition of the phenols in BDP.
The decomposition rates for PN, RS, and PC (Fig. 2)
are related as 1 : 1.2 : 1.4. Thus, PN proved to be the