ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 12, pp. 2162–2165. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © O.V. Zhukova, V.V. Medvedeva, Yu.D. Semchikov, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 12,
Gelation in Sodium Lignosulfonate Solutions in the Presence
of a Hexavalent Chromium Salt
O. V. Zhukova, V. V. Medvedeva, and Yu. D. Semchikov
Nizhni Novgorod State Medical Academy, Nizhni Novgorod, Russia
Research Institute of Chemistry, Lobachevsky State University, Nizhni Novgorod, Russia
Lobachevsky State University, Nizhni Novgorod, Russia
Received August 5, 2008
Abstract—Gelation in the system sodium lignosulfonate–hexavalent chromium salt was studied. Isothermal
phase diagrams were constructed, and the critical gelation concentrations of the polymer and cross-linking
agent were determined. The time evolution of the elastic modulus of the gels was examined.
Raising the productivity of oil and gas wells is a press-
ing problem today. For this purpose, secondary and
tertiary oil recovery processes are used, e.g., flooding
with polymer solutions. This technique comprises in-
jection of a polymer solution of increased viscosity
through injection wells. However, injection of a poly-
mer solution is not always an effective tool for raising
the formation pressure. In this case, there is a need for
systems with advanced mechanical characteristics,
e.g., hydrogels, which could be prepared through gela-
tion of the polymer via interaction of its functional
groups with cross-linking agents .
Oil and gas industry employs various water-
soluble polymers, such as polyacrylamide and its co-
polymers and cellulose ethers . Previously, we have
performed a rather thorough study of the gelation in
hydroxyethyl cellulose and sodium carboxymethyl cel-
lulose solutions, including syneresis and dynamics of
viscoelastic properties of these gels, and also the effect
of pH and alkali metal salts on their characteristics [3–5].
It has been shown that Sodium lignosulfonate (NaLS)
is the most promising as a polymer for use in oil and
gas industry . Being a by-product of sulfite cellulose
manufacture, this polymer is inexpensive and readily
available. It forms coordination cross-linked gels in the
presence of transition metal salts [7, 8]. The use of
such gels in oil and gas industry facilitates solution of
at least two problems, one of which is environmental
(utilization of wastes from pulp-and-paper industry)
and another, economic (reducing the cost of reagents
for oil and gas production).
There is only limited published information on
NaLS-based gels .
In this study, we examined the gelation in NaLS
solutions in the presence of Cr
ions. The formation
of such gels has been studied earlier, but therehave
been no comprehensive studies because of the com-
plexity of the process and problems arising in its prac-
tical implementation. Also the effects of alkali and al-
kaline-earth metal salts on the critical gelation concen-
tration and mechanical characteristics of the resulting
gels have been studied. These effects are of great prac-
tical significance in view of the fact that these salts are
always present in formation water.
AND POLYMERIC MATERIALS
In the study, we used commercial solid NaLS
from Solikamsk Pulp and Paper Combine.
In gelation experiments, we used 40–50 wt
NaLS solution in distilled water and 10–50 wt
tions of potassium (K
) or sodium dichromate
O). Initially we prepared the gels in
the presence of potassium dichromate. However, its
solubility in water is only 12.5 g/100 g H
O, which is
much lower than that of the sodium salt (180.0 g/100 g
O, 20°C). Therefore, all the subsequent experiments
were performed with sodium dichromate.
To examine the effect of alkali and alkaline earth
metal salts on gelation, 0.5–3.0 M NaCl and 0.5 M
O were introduced into the system.