Effect of Modification of a Sulfonic Cation-Exchange Membrane
with Cross-Linked Chitosan on the Selectivity
of the Transport of Magnesium and Calcium Ions
Relative to Sodium Ions
V. P. Greben’, I. G. Rodzik, and L. G. Kolzunova
Institute of Chemistry, Far-Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
Received May 27, 2010
Abstract—A procedure was suggested for modification of MK-40 sulfonic cation-exchange membrane by
application of a chitosan layer onto its surface, followed by cross-linking of this layer with epichlorohydrin.
The transport of magnesium, calcium, and sodium ions through cation-exchange membranes modified with
cross-linked and non-cross-linked chitosan was studied.
AND POLYMERIC MATERIALS
ISSN 1070-4272, Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 3, pp. 473–478. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © V.P. Greben’, I.G. Rodzik, L.G. Kolzunova, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 3, pp. 483–487.
The development of cation-exchange membranes
selectively permeable to a definite kind of cations is of
practical importance, because their use in electro-
dialysis will allow separation, purposeful synthesis,
and purification of inorganic and organic substances.
By now, membranes for separation of single- and
multicharged cations have been prepared. To this end,
in particular, the surface of cation-exchange membranes
is treated with compounds containing cationic sur-
factants that do not pass into the membrane, e.g., with
poly(4-vinyl-N-propylpyridinium) bromide  or hexa-
decylpyridinium chloride . As a rule, the membrane
side that subsequently contacts with the diluate in an
electrodialyzer is subjected to the treatment. The
modifier is applied by various procedures: (a) intro-
duction of surfactants into solution, followed by their
electrodeposition on the membrane surface; (b) soaking
of the membrane in a surfactant solution (sorption of
surfactants by the membrane surface; (c) application of
a surfactant solution onto the membrane surface,
followed by evaporation of the solvent (most fre-
quently water) [3, 4].
Today the largest number of papers concern
application of polyethylenimine onto the surface of a
cation-exchange membrane by various procedures. In
particular, Amara and Kerdjoudj  prepared by elec-
trodeposition of polyethylenimine a cation-exchange
membrane selectively permeable to single-charged
ions compared to double-charged ions. However, this
method has a drawback: The modifiers, especially
those of non-cross-linked structure, that are not bound
to the membrane surface can leave the membrane
surface and pass into a solution when the electric
current is not passed through the electrodialyzer. The
most widely used procedure for modification of
membranes containing in the bulk or on the surface
sulfonyl chloride or sulfonyl fluoride groups is applica-
tion onto a membrane of tetraethylenepentamine ,
polyethylenimine [6, 7], or diamines , which form a
sulfamide bond with the polymeric matrix of the
membrane. Additional cross-linking with epichloro-
hydrin of polyethylenimine bound to the membrane
surface by sulfamide bonds  ensured steadily high
selectivity of the membrane to single-charged ions.
It was shown previously  that modification of
the surface of a cation-exchange membrane with
chitosan appreciably decreases the transport of
magnesium ions compared to sodium ions.
In this study we examined the effect exerted by
cross-linked chitosan on the selectivity of the transport
of calcium and magnesium ions relative to sodium ions
through a cation-exchange membrane modified with