1070-4272/01/7403-0498$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 3, 2001, pp. 498!500. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 3,
2001, pp. 487!489.
Original Russian Text Copyright + 2001 by Navrotskii, Novakov, Makeev, Orlyanskii, Kozlovtsev, Kotlyarevskaya, Navrotskii.
AND POLYMERIC MATERIALS
Effect of Molecular Weight
of Poly-(1,2-Dimethyl-5-Vinylpyridinium Methyl Sulfate)
on Flocculation of Aqueous Kaolin Suspension
A. V. Navrotskii, I. A. Novakov, S. M. Makeev, V. V. Orlyanskii, V. A. Kozlovtsev,
O. O. Kotlyarevskaya, and V. A. Navrotskii
Volgograd State Technical University, Volgograd, Russia
Received April 21, 2000
Abstract-Effect of molecular weight of poly-(1,2-dimethyl-5-vinylpyridinium methyl sulfate) on flocculation
of aqueous kaolin suspension is studied.
Up-to-date water treatment processes suggest the
use of reagents providing destabilization and enhanced
separation of a dispersed phase contained in water
[1, 2]. Among these reagents cationic polymer electro-
lytes usually show high performance. Their dissocia-
tion in a solution with formation of high-molecular-
weight polycations ensures a complex flocculating ef-
fect by virtue of neutralization of a negative surface
charge of suspended particles and simultaneous forma-
tion of bridging bonds between them [2, 3]. In our
opinion, poly-(1,2-dimethyl-5-vinylpyridinium methyl
sulfate) (poly-1,2-DM-5-VPMS) shows promise as
such a cationic polyelectrolyte.
Previously we demonstrated that poly-1,2-DM-
5-VPMS with desired molecular and rheological char-
acteristics can be synthesized in the presence of a
series of peroxide initiators, tert-butylperoxypropanol
being the most efficient among them [4, 5]. Based on
this result a process for synthesis of poly-1,2-DM-
5-VPMS was developed and production of KF-91
cationic flocculant based on it was organized. This
flocculant was tested in various processes , and its
high performance as a reagent for water treatment is
beyond question. However, we believe that the effi-
ciency of using KF-91 may be increased by virtue of
optimization of the process conditions.
In this work we studied the effect of the molecular
weight of poly-1,2-DM-5-VPMS on flocculation of
aqueous kaolin suspension.
Poly-1,2-DM-5-VPMS was synthesized and iso-
lated as in . As a dispersion phase we used kaolin
(KSD brand) with a mean particle size of 7 mm.
In flocculation experiments the kaolin concentra-
tion was 4%, and the poly-1,2-DM-5-VPMS concen-
was 0.012532.0 mg/g kaolin. The system
was stirred, and the travel time of the flocculi/super-
natant boundary from the first to the second mark on a
cylinder was measured to estimate the sedimentation
. Also the turbidity of the supernatant t was
measured 30 min after.
From the experimental data thus obtained we deter-
mined the optimal concentrations of the polyelectro-
lytes. The criterion was the minimal turbidity of the
supernatant, i.e., the maximal degree of clarification,
and the maximal rate of floccule sedimentation. The
clarification and flocculation factors D
estimated by the following equations:
) ! 1, D
) ! 1,
are the supernatant turbidity, re-
spectively, without and with the polyelectrolyte added
in the optimal concentration; and V
the floccule sedimentation rates under the same con-
Introduction of poly-1,2-DM-5-VPMS of various
molecular weights considerably increases both the
suspension sedimentation rate and the rate of sedimen-
tation of flocculi of the kaolin suspension (Fig. 1).
The supernatant turbidity plotted against the floccu-
lant concentration shows extrema (Fig. 1a), which is
typical of the systems solid3water3polyelectrolyte .
The polyelectrolyte concentration providing floccula-
tion of the dispersed system ranges from 0.025 to