ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 1, pp. 103−109. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © I.A. Palamarchuk, O.S. Brovko, K.G. Bogolitsyn, T.A. Boitsova, A.V. Ladesov, A.D. Ivakhnov, 2015, published in Zhurnal Prikladnoi
Khimii, 2015, Vol. 88, No. 1, pp. 109−114.
Relationship of the Structure and Ion-Exchange Properties
of Polyelectrolyte Complexes Based on Biopolymers
I. A. Palamarchuk
, O. S. Brovko
, K. G. Bogolitsyn
, T. A. Boitsova
A. V. Ladesov
, and A. D. Ivakhnov
Institute of Environmental Problems of the North, Ural Branch, Russian Academy of Sciences,
nab. Severnoi Dviny 23, Arkhangelsk, 163000 Russia
Northern (Arctic) Federal University, nab. Severnoi Dviny 17, Arkhangelsk, 163002 Russia
Received December 10, 2013
Abstract—Ion-exchange properties of polyelectrolyte complexes based on lignosulfonates and chitosan were
studied. Optimum conditions were found for preparing polymeric sorbents with the maximal sorption capacity
for cationic and anionic pollutants.
Sorption methods for wastewater treatment to remove
various pollutants are the most promising today, and the
major problem is search for effective and cheap sorbents.
Sorbents prepared from natural raw materials are of
particular interest. Chitin and lignin along with cellulose
are the major components of renewable resources;
therefore, increased attention is paid to the development
of new methods for their chemical modiﬁ cation.
It was shown previously [1–3] that sulfonated lignins
react with chitosan to form polyelectrolyte complexes
(PECs): water-insoluble (stoichiometric) and water-
insoluble (nonstoichiometric). Nonstoichiometric
complexes are formed by direct mixing of nonequimolar
amounts of the components at such pH values at which
both polyelectrolytes (PEs) are charged. It is known that
such reactions are described by the main relationships
found for the reactions between oppositely charged
polyelectrolytes, because in aqueous solutions both
lignosulfonates (LSs) and chitosan (CT) exhibit typical
In a deﬁ nite interval of the concentrations of the inter-
acting PE pairs, the phase separation occurs as precipitate
formation and is accompanied by disproportionation, i.e.,
by redistribution of the macro-molecular components
between particles of the complex, with the stoichiometric
complex precipitating. PECs in the solid phase are water-
insoluble polymer matrices exhibiting limited swelling
in water; in some properties, they resemble well-known
cross-linked hydrogels. The structure of swollen insoluble
PECs can be presented in the general form as alternation
of hydrophobic “ladder” areas linked by salt bonds and
hydrophilic defective areas (loops and tails) with ionic
groups not involved in ion–ion bonds. Interest in such
complexes is mainly due to the possibility of using them
as sorbents, ﬁ lms, and membranes [4, 5].
Despite problems with studying the sorption
mechanism, sorbents based on biopolymers are of
indubitable practical and scientiﬁ c interest. Owing to
speciﬁ c features of structural organization, they can be
considered as efﬁ cient sorbents not only for cations, but
also for anions.
In this study we analyze how the ratio of oppositely
charged polyelectrolytes inﬂ uences the structure of the
forming complexes and their sorption properties.
Chitosan was purchased from ZAO Bioprogress, All-
Russia Research and Technological Institute of Biological
Industry (Moscow oblast, Russia). It had the molecular