Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 1, pp. 88−94.
Pleiades Publishing, Ltd., 2014.
Original Russian Text D.A. Kazakov, V.V. Vol’khin, I.S. Borovkova, N.P. Popova, 2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87, No. 1, pp. 93−99.
Kinetics of Oxygen Absorption by Aqueous Electrolyte Solutions
in the Presence of Microencapsulated Quartz Particles Activating
the Mass Transfer in the Liquid Phase
D. A. Kazakov, V. V. Vol’khin, I. S. Borovkova, and N. P. Popova
Perm National Research Polytechnic University, Komsomolskii pr. 29, Perm, 614990 Russia
Received October 1, 2013
Abstract—Effect of the ion composition of aqueous solutions on the oxygen absorption kinetics in a system
constituted by a gas (air) and a liquid (aqueous solution) in the presence of microencapsulated quartz particles
activating the mass transfer in the liquid phase was studied. It was found that ions with positive hydration cause
a substantial decrease in the O
mass-transfer enhancement factor, whereas ions with negative hydration lead to its
increase under the same conditions. It is shown that the effect of ions on the rate of oxygen absorption by aqueous
electrolyte solutions can be prognosticated on the basis of data on the inﬂ uence of these ions on the structure and
viscosity of water. The results of the study can serve as a basis for varying the rate of heterogeneous reactions
in gas–liquid systems, whose rate is limited by the mass transfer of oxygen into aqueous media, by purposeful
control over their ion composition.
Oxygen has low solubility (Henry constant H =
4.56 × 10
Pa at 25°C ) and molecular diffusion
coefﬁ cient (D = 1.98 × 10
at 20°C ) in water.
As a result, the O
absorption by aqueous media is rather
slow. At the same time, oxygen is frequently used in
technological processes as an agent oxidizing organic
and inorganic compounds dissolved in the aqueous phase
[3, 4]. If, in this case, the kinetic stage of the oxidation
process is fast, the O
absorption by the aqueous phase
becomes rate-determining. For example, the mass transfer
in a gas–liquid system may be the rate-determining
stage for liquid-phase catalytic oxidation of glucose to
give the much-in-demand gluconic acid , catalytic
oxidation and biodegradation of phenol in wastewater
[6, 7], and biotechnological processes using aerobic
microorganisms . The bubbling and(or) enhanced
agitation of the gas and liquid phases, conventionally
employed to intensify the mass transfer of O
energy-intensive and frequently insufﬁ ciently efﬁ cient
for transferring the process to the kinetic mode .
Therefore, new approaches are necessary for intensifying
the interphase transport of O
Use of ﬁ nely dispersed solid substances possessing
a certain set of physicochemical characteristics that enable
purposeful control over the boundary layer of a liquid is
presently considered as one of the most promising ways to
raise the mass-transfer rate in gas–liquid systems [6, 10].
Solid additives based on various materials have been
suggested for intensifying the mass transfer of oxygen:
activated carbon , metal oxides , and polymeric
Analysis of published data shows that activated carbon
is the most effective among the additives suggested for
enhancement of the O
mass transfer. Use of activated
carbon particles for intensiﬁ cation of heterogeneous
reactions seems to be of little practical promise because
they can adsorb considerable amounts of reagents and
reaction products, which is commonly undesirable.
The previously obtained ﬁ nely dispersed solid-phase
material, constituted by quartz particles in a poly(vinyl
chloride) shell (SiO
/PVC), does not have a developed
speciﬁ c surface area or pronounced adsorption capacity.
However, it has been shown that this material can make