ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 5, pp. 800!802. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + M.D. Vedenyapina, Yu.N. Eremicheva, V.A. Pavlov, A.A. Vedenyapin, 2008, published in Zhurnal Prikladnoi Khimii, 2008,
Vol. 81, No. 5, pp. 765!767.
AND CORROSION PROTECTION OF METALS
Electrochemical Degradation of Tetracycline
M. D. Vedenyapina, Yu. N. Eremicheva, V. A. Pavlov, and A. A. Vedenyapin
Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
Received August 13, 2007
Abstract-Oxidation of tetracycline
in an electrochemical cell with separated cathodic and anodic com-
partments on smooth platinum was studied. The extent of electrochemical degradation of tetracycline and
the energy consumption for eliminating the biological activity of its aqueous solutions were estimated.
(TC) is a widely used antibiotic.
However, in a human body it undergoes only partial
metabolism. When getting into sewage, it suppresses
the vital activity and growth of microorganism col-
onies used on water treatment plants. This results in
environmental pollution with untreated wastewater
[1!3] and in penetration of harmful substances into
living bodies .
To prevent ingress of TC into water treatment
plants, it is suggested to use electrochemical anodic
oxidation on anodes-catalysts . This method is
widely used for neutralization of toxic organic sub-
stances polluting waste and natural waters. In the
process, relatively small molecules such as phenol
and its derivatives can be completely mineralized by
electrochemical oxidation to CO
addition of 10!16 electrons [5!7]. Canizares et al.
 suggested a method for electrochemical oxidation
of phenol in a concentration of 200!400 mg l
sewage with acceptable outlay.
According to the previous data , reducing the
biological activity of a TC solution by an order of
magnitude does not require its complete mineraliza-
tion. It is sufficient to break down the initial TC
molecules. However, the level of electric power con-
sumption for electrochemical oxidation of TC, re-
quired to completely eliminate its biological activity,
was not determined previously.
In this study we examined oxidation of TC on a
platinum anode at various TC concentrations, deter-
mined the product yields as functions of current, and
calculated from these data the amount of electricity
spent for the oxidation of TC on platinum.
Electrochemical oxidation of TC was performed
in a glass cell with the anodic and cathodic compart-
ments separated by an ion-exchange membrane. The
anode and cathode were arranged parallel to each
other at a distance of 2 cm. A platinum plate of the
surface area 10 cm
served as a cathode. The same
platinum plates served as anodes. The current den-
sity was 5 mA cm
. The anode potential vs. silver
chloride electrode was 1.82!1.89 V. The TC concen-
tration was 50!500 mg l
. As supporting electrolyte
we used 0.1N aqueous H
. The solutions were
analyzed by HPLC and polarimetry. The gas phase
was analyzed by GLC.
Chromatographic analysis of the reaction mix-
tures from TC oxidation revealed formation of sev-
eral products. The content of one of them monotoni-
cally increases in the course of the reaction, whereas
the content of the other products, irrespective of the
TC conversion, does not exceed 5% of the content
of the major product. The TC content of the solu-
tion decreases with time (Fig. 1), and for all the con-
centrations studied it can be described by a first-
where c and c
are the initial and running TC con-
centrations in the solution (M); t, time from the
reaction start (s); and k, oxidation rate constant
equal to (0.9!1.1) 10
Chromatographic analysis showed that the CO
release from the cell was negligible and did not ex-
ceed 0.5%. This allowed us to determine the current