ISSN 1070-4272. Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 5, pp. 769!773. + Pleiades Publishing, Inc., 2006.
Original Russian Text + Yu.S. Dzyaz’ko, V.N. Belyakov, N.V. Stefanyak, S.L. Vasilyuk, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79,
No. 5, pp. 778!782.
AND CORROSION PROTECTION OF METALS
Anion-Exchange Properties of Composite Ceramic Membranes
Containing Hydrated Zirconium Dioxide
Yu. S. Dzyaz’ko, V. N. Belyakov, N. V. Stefanyak, and S. L. Vasilyuk
Vernadsky Institute of General and Inorganic Chemistry, National Academy of Sciences of Ukraine,
Received November 16, 2005
Abstract-Composite membranes consisting of an inert ceramic matrix based on aluminum and zirconium
oxides and of an ion-exchange component, hydrated zirconium dioxide, were prepared. The selectivity of
these membranes to Cl
ions was studied.
Process cycles of many industrial enterprises in-
volve the formation of highly toxic wastes, including
soluble inorganic compounds. A promising method of
removing such impurities from solutions is electro-
dialysis, as it allows continuous recovery of both
cations and anions and their simultaneous concentra-
tion . This method involves the use of both
cation- and anion-exchange membranes made of or-
ganic polymers. The presence of oxidizing anions in
solutions results in irreversible deterioration of mech-
anical and ion-selective properties of anion-exchange
membranes. In this connection, an urgent problem is
obtaining anion-exchange membranes with increased
resistance to oxidants.
Hydrated oxides of multiply charged metals are
highly stable in corrosive media . At the same time,
in acid media these compounds show anion-exchange
properties. For example, the anion exchange with
hydrated zirconium(IV) dioxide (HZD) proceeds ac-
cording to scheme (1) [6, 7]:
where m and p are integers.
This fact suggests that hydrated zirconium oxide
can be used for production of chemically
stable anion-exchange membranes.
The aim of this study was to develop such mem-
branes and to examine their anion-exchange proper-
ties. For comparison we also studied a dispersed HZD
ion exchanger obtained by similar methods.
We used inert ceramic membranes based on Zr and
Al oxides as starting materials. They had the follow-
ing characteristics: molar ratio Al
pore diameter 0.19 mm, specific surface area 4.53
. The membranes had the shape of tubes
(internal diameter 10 mm, wall thickness 1 mm,
length 20 cm).
Series I of samples of the anion-exchange mem-
branes was prepared as follows. An inert membrane
was filled with HZD in stages by a direct precipitation
of particles of the ion-exchange component in the
matrix volume. Each cycle of the preparation proce-
dure included the following stages.
(1) Preparation of a ZrO
sol by gradual ad-
dition of 1 M NH
OH solution to 1 M ZrOCl
vigorous stirring. The volume ratio of the solutions
was approximately 1 : 1. The temperature of the reac-
tion mixture was maintained at a level of 330 K.
The sol was left to stand for 48 days at 298 K.
(2) Impregnation of the membrane by the sol for
(3) Treatment of the membrane with 1 M NH
(4) Washing with deionized water to neutral reac-
(5) Drying at 298 K to constant weight.
For more complete filling of matrix pores, opera-
tions 135 were multiply repeated. Membranes with
various degrees of filling were prepared by this proce-