Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 3, pp. 368−371.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © N.K. Luneva, M.Z. Gavrilov, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 3, pp. 376−379.
OF SYSTEMS AND PROCESSES
Ion Exchange Properties of Heat-Treated
N. K. Luneva and M. Z. Gavrilov
Institute of General and Inorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus
Received May 27, 2010
Abstract—Ion exchange properties of carbon ﬁ bers obtained by heat treatment in a temperature range of 200–600°С
in an inert atmosphere of cellulose-regenerated impregnated by 0.3–3.0 M ammonium chloride were examined.
Carbon ion exchangers in contrast to synthetic
possess high chemical, thermal, radiation resistance that
allows their use in harsher conditions. Application of
the carbon ion exchangers as ﬁ bers simpliﬁ es equipping
sorption operations, increases a rate of cleaning various
solutions. A synthesis of carboxyl-containing carbon
materials by pyrolysis of monocarboxyl cellulose
(MCC) and ammonium salt is known. Also sulfonation
of carbon materials was described. It was established
that temperature of MCC pyrolysis and carbon material
sulfonation essentially effects on the ion exchange
It is known that ammonium chloride is a catalyst of
cellulose-regenerated (CR) carbonization, its applica-
tion as a composition impregnating cellulose enables
conduction of the process with a sufﬁ cient rate and
producing carbon ﬁ bers (CFs) of high physical and me-
chanical characteristics and yield of solid residue [2, 3].
A formation of nitrogen-containing carbon ﬁ ber
proceeds due to CR interaction with products of NH
dissociation in a range of 160–300°С [4, 5].
Chemical nitrogen ﬁ xation by coke residue of
thermal transformation of CR ﬁ bers was also found
in heat treatment of the ﬁ bers in the presence of other
ammonium salts [4–6]. An amount of nitrogen in CFs
depends mainly on the content NN
Cl in the original
ﬁ ber, as well as on the treatment temperature and can
reach several percent. However, the mechanism of this
reaction was not described in literature.
Nitrogen-containing carbon ﬁ bers have a fairly high
thermal stability. It has been suggested that nitrogen is
a constituent of the functional groups of CFs possessing
anion-exchange properties [3, 4]. Kurnevich et al. 
proposed a reaction scheme according to which in the
initial stage of thermal decomposition of CRs in the
presence of ammonium salts at the C
atom of cellulose
formation of aldehyde groups occurs. They interact with
the evolved ammonia to form Schiff bases.
The purpose of this study was to investigate the
properties of ion exchange carbon ﬁ ber obtained
by heating CR ﬁ bers impregnated with aqueous
solutions of NN
Cl in an inert atmosphere at different
The carbon ﬁ ber residues of the pyrolized and
previously treated CR ﬁ bers impregnated by 0.3–3.0 M
solution of NH
Cl were an object of the examination.
Pyrolysis was performed with rate of 1.5 deg min
a temperature range of 20–600°С in ﬂ ow of an inert
gas. Then samples were washed with boiling distilled
water to neutral pH value and then with alcohol and
dried. Nitrogen determination of the obtained samples
was done by Kjeldahl method . Transformation of ion
exchanger into acidic form was performed by treating
with 0.1 N HCl followed by washing with hot bidistilled