1070-4272/04/7710-1685 C 2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 10, 2004, pp. 1685!1692. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004,
Original Russian Text Copyright + 2004 by Novakov, S. Radchenko, F. Radchenko.
AND POLYMERIC MATERIALS
Water-Soluble Polymer-Colloid Complexes of Aluminum
Polyhydroxochloride and Polyacrylamide in Separation
of Model and Real Dispersions
I. A. Novakov, S. S. Radchenko, and F. S. Radchenko
Volgograd State Technical University, Volgograd, Russia
Received March 1, 2004
Abstract-The activity of polymer-colloid complexes of aluminum polyhydroxochloride and polyacrylamide
in separation of model kaolin dispersions and some real dispersions was studied under free and hindered
particle sedimentation conditions.
The stability of dispersed systems is frequently con-
trolled with flocculants, water-soluble macromolecular
compounds, either natural or specially synthesized.
Aluminum salts combined with certain polymers,
above all polyacrylamide (PAA), have long been ap-
plied to water treatment [1, 2]. The main function of
such components is to improve the flocculation in set-
tlers and to reduce the water clarification time. How-
ever, the metal and the functional groups of the poly-
meric molecule of the flocculant can form ionic or
coordination bonds. Schwartz and Francois  and
Anufrieva et al.  studied reactions of a number
of metals (Fe
, and rare-earth elements)
with water-soluble polymers of various chemical struc-
tures and, in particular, with PAA. It was found that
stable metal-containing polymeric complexes are
formed in such systems via intramolecular complexa-
tion accompanied by a decrease in the conformational
mobility of the macromolecules. Kudaibergenov et al.
 studied the reaction between iron(IIII) chloride and
nonionic and hydrolyzed PAA and showed that the
coordination bond links the iron ions and the carbonyl
groups of PAA. The resulting intramolecular ion-co-
ordination cross-links are responsible for the compac-
tion of the macromolecules: The hydrodynamic size of
the particles of hydrolyzed PAA in water decreases
from 2000 to 400 A. At the same time, the conforma-
tion of the macromolecules and their hydrodynamic
size in aqueous solutions are of primary importance in
flocculation and sedimentation of dispersed particles.
It has been shown  that the combined use of
flocculants and inorganic coagulants in sedimentation
of model kaolin and ocher dispersions can exert either
synergistic or antagonistic effect, depending on the
order in which the reagents are introduced.
More recent works  are concerned with
formulations based on polyacrylamide and certain
inorganic salts, whose high activity in flocculation
and sedimentation of suspensions in potable water and
wastewater treatment was noted by Gordeev-Gavrikov
et al. . Data on such formulations are scarce.
These investigations are still in infancy, as suggested
by the fact that the authors use terms like [alternative
organomineral coagulants,][inorganic polymeric floc-
culants,] etc. [14, 15], which need to be defined more
We have shown previously  that mixing of
aqueous solutions of PAA with aluminum polyhy-
droxochloride (APHC), as well as polymerization of
acrylamide (AA) in an aqueous APHC solution, yields
polymer-colloid complexes (PCCs) . It was reason-
able to test them both as flocculants for high-concen-
tration dispersions and as coagulants for low-concen-
tration aqueous dispersions (such as natural water).
The poly complexes were prepared  by mixing
aqueous solution of PAA (3 wt %) and APHC at room
temperature or by polymerization of AA in an aqueous
solution of APHC in the presence of an initiator, po-
tassium persulfate. In both cases, the molar ratio of
to the PAA unit was varied from 0.25 to 10.
The PCCs prepared were kept at room temperature for
2 days. The APBC obtained by the method described
in  had the following characteristics: Al(III)
content 12.8 wt %, Cl
atomic ratio 0.48,
pH 4.5, r = 1330 kg m
, dry residue 46.5 wt %.