Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 10, pp. 1521−1525.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © F.Kh. Khakimova, D.R. Nagimov, R.R. Khakimov, O.A. Noskova, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86,
No. 10, pp. 1565−1570.
OF HETEROGENEOUS SYSTEMS
New Solutions in the Technology
of Chlorine-Free Bleaching of Cellulose
F. Kh. Khakimova, D. R. Nagimov, R. R. Khakimov, and O. A. Noskova
Perm National Research Polytechnic University, Perm, Russia
Received April 17, 2013
Abstract—Sequence for hydrogen peroxide bleaching of sulﬁ te cellulose without use of chlorine-containing
compounds was developed. It is shown that alternation of acid and alkaline stages of bleaching leads to swell-
ing or contraction of cellulose ﬁ bers, depending on the pH of the medium, and, accordingly, to a change of the
microstructure of the ﬁ bers, and just this circumstance improves the bleaching efﬁ ciency. An important speciﬁ c
feature of the bleaching with hydrogen peroxide by the suggested technique, compared with the conventional
methods using chlorine-containing reagents, is the mild oxidative effect on cellulose and substantial decrease in
the mass fraction of tars and fats in cellulose, which favors practical solution of tar problems in paper industries.
Cellulose bleaching is one of the most important stages
in manufacture of bleached cellulose for fabrication of
white kinds of paper and cardboard. The most important
ecological issue in the cellulose production technology is
the formation of organochlorine compounds in cellulose
bleaching and their content in bleached cellulose and
wastewater from the bleaching plant. In international
practice, these compounds are commonly characterized
by the parameters AOX (adsorbable organic halides) 
or OBC (organically bound chlorine) .
The conventional way to diminish the environmental
stress in cellulose bleaching is to exclude molecular
chlorine and hypochlorites from the bleaching sequence.
The main direction in the development of the bleaching
technology is to pass to cellulose bleaching without
molecular chlorine (ECF, elemental chlorine free
technique) or chlorine-containing reagents (TCF, total
chlorine free technique) .
The bleaching by the ECF method most frequently
employs the oxygen-alkaline treatment (EO) in the
deligniﬁ cation stage and treatment with chlorine
dioxide in the ﬁ nal stage. However, the EO needs
intricate equipment because the process occurs under
increased pressure and use of chlorine dioxide requires
that a pulp-and-paper plant should have a special shop
for its production from the explosive sodium chlorate. In
addition, the degree of AOX removal in the conventional
biological wastewater puriﬁ cation is 14–71% and
varies between individual chlorinated compounds. That
is, offsite sewage works do not prevent stable toxic
bioaccumulated organochlorine compounds present
in bleaching wastewater from penetrating into water
basins and, only with the formation of compounds of
this kind in cellulose bleaching precluded, the protection
of the biosphere from their detrimental inﬂ uence can be
A rather ecologically safe method is the TCF
cellulose bleaching with oxygen-containing reagents,
and especially hydrogen peroxide, which is a widely
used bleaching agent. However, its application in Russia
has been extremely limited so far.
A promising solution in the suggested bleaching
technology is by alternation of cellulose mass treatment
stages with alkaline hydrogen peroxide solutions
and acetic acid. The EP-Pd-AA-P-A sequence was
developed for bleaching of cellulose with residual