1070-4272/05/7812-2024 + 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 12, 2005, pp. 2024!2025. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 12, 2005,
Original Russian Text Copyright + 2005 by Kozyreva, Kolesnikova, Glukhareva, Lebedeva.
Oxidative Degradation of Neonol AF 9-12
Yu. N. Kozyreva, E. N. Kolesnikova, N.A. Glukhareva, and O.E. Lebedeva
Belgorod State University, Belgorod, Russia
Received August 22, 2005
Abstract-The oxidative degradation of a difficultly degradable surfactant, oxyethylated isononylphenol
(Neonol AF 9-12), with aqueous hydrogen peroxide containing iron(III) chloride was studied tensimetrically.
The wide application of surfactants, primarily,
household chemicals, leads to wastewater pollution
with these agents. As a rule, surfactant-containing
municipal wastes of large cities are treated at waste-
water treatment plants in combination with some in-
dustrial wastes. However, biodegradation of some
surfactants is not sufficiently fast to decrease their
content in decontaminated wastewater to the level
of the maximum permissible concentration (MPC).
Oxyethylated alkylphenols, the only type of nonionic
surfactants produced in Russia, belong to extremely
slowly degradable [biologically hard] surfactants.
To remove these surfactants from wastewater, local
treatment facilities and specific physicochemical tech-
nique are required .
Published methods for water treatment to remove
oxyethylated alkyphenols are few. The degradation of
Igepal CA 520 commercial product mainly consisting
of oxyethylated octylphenol with varied degree of
oxyethylation was studied in . It was found that
UV light (365 nm) decomposes this surfactant in
the presence of iron(III).
The oxidative degradation of oxyethylated alkyl-
phenols shows much promise in view of the fact that
this procedure has been successfully used for degrada-
tion of other chemically resistant xenobiotics. The Fen-
ton reagent [mixture of hydrogen peroxide with iron(II)
or iron(III) salts] is one of the most efficient oxidants
. The iron cations present in this reagent induce
the hydrogen peroxide decay by a radical mechanism.
The oxidative degradation of oxyethylated iso-
nonylphenol with hydrogen peroxide in the presence
of iron(III) was studied in . It was found that this
surfactant is effectively decomposed by hydrogen per-
oxide. In this study, with Neonol AF-9-12 as an ex-
ample, we attempted to evaluate the extent of its ox-
idative degradation under the action hydrogen perox-
ide and to find the optimal conditions of this process.
In our experiments, we used oxyethylated isononyl-
phenol with an average degree of oxyethylation of
12 (Neonol AF 9-12, Neonol) produced by Nizhne-
kamskneftekhim Limited Liability Company in ac-
cordance with TU (Technical Specifications) 38.507-
Neonol was subjected to oxidative degradation
by its treatment with aqueous hydrogen peroxide in
the presence of iron(III) at varied concentrations of
these reagents. The oxidant solutions were prepared
in twice-distilled water.
The Neonol oxidation was monitored by surface
tension measured by the ring detachment technique
on a Kruss tensimeter at room temperature (23oC).
In all the experiments, the Neonol concentration
was 6.7 0 10
M. This value is lower than the critical
micelle concentration (CMC) of Neonol. Therefore,
even minor variations in the Neonol concentration
give rise to noticeable changes in the surface tension.
In contrast, at the surfactant concentration exceed-
ing CMC, the surface tension is insensitive to the sur-
The surface tension at the initial Neonol concen-
tration was 38 mN m
. On adding hydrogen peroxide
to aqueous Neonol, the surface tension did not change
significantly: the surface tension was 37.5 mN m
1 h, and 34 mN m
after 1 day. On keeping aqueous
Neonol without adding hydrogen peroxide for 1 day,
the surface tension decreases to a similar extent owing
to attainment of the equilibrium sorption of Neonol
at the interface between the aqueous surfactant and air.
A different pattern is observed after adding H
in combination with a Fe(III) salt to aqueous Neonol.
In this mixture, the surface tension noticeably in-
creases after 15 min (see Fig. 1a), and this increase