Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 8, pp. 1176−1181.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © V.V. Samonin, M.L. Podvyaznikov, M.S. Chentsov, E.A. Spiridonova, V.L. Kiseleva, 2012, published in Zhurnal Prikladnoi Khimii,
2012, Vol. 85, No. 8, pp. 1233−1238.
OF SYSTEMS AND PROCESSES
Effect of AC Magnetic Field on Adsorption of Benzene
and Ethanol Vapors by Activated Carbons
V. V. Samonin, M. L. Podvyaznikov, M. S. Chentsov,
E. A. Spiridonova, and V. L. Kiseleva
St. Petersburg State Technological Institute, St. Petersburg, Russia
Received June 1, 2012
Abstract—Effect of a magnetic ﬁ eld on sorption processes from gas media on activated carbons was studied.
Speciﬁ c features of the adsorption process of ethanol and benzene vapors in an ac magnetic ﬁ eld of industrial
frequency are demonstrated for the example of industrial activated carbons, depending on porous structure pa-
rameters and presence of magnetoactive admixtures in the sorbent.
Speciﬁ c features of the surface of sorption materials,
including activated carbons, are due to the energy state of
surface atoms, different from that in the bulk. The point
is that the carbons exhibit paramagnetic properties on
which depends, in particular, the nature of adsorption of
organic solvent vapors. It has been shown  by the EPR
technique that, in contrast to the starting carbons whose
paramagnetism is due to oxygen-containing groups, that
of carbonized products is determined by the presence of
free radicals stabilized by the developed sorbent surface
and the density of paramagnetic centers extremally
depends on the carbonization temperature. This surface
is a polyconjugated system (PCS) of carbon chains, and
in the simplest case, triphenyl radicals . The presence
of a free charge distributed over the surface enables
transformation of radicals under external impacts, which
favors recharging of surface regions and changing of the
position of active centers.
It has been more than once noted in the scientiﬁ c
and technological literature  that, in addition to
the highly developed microporosity, the amount and
composition of ash impurities are among the most
important characteristics responsible not only for the
application area of a sorbent, but also directly for the
sorption and catalytic properties of activated carbons,
which are manifested, in particular, in high-temperature
regeneration . Being coked, products of incomplete
decomposition of organic substances can poison the active
and transport porosity of the adsorbent, which raises the
energy expenditure for regeneration and, consequently,
impairs the application efﬁ ciency of sorbents in their
repeated use. When external electromagnetic treatments
are used to affect the sorption capacity of activated
carbons, it is necessary to take into account not only the
catalytic properties of ash components, but also their
own magnetoactive properties.
It has been noted previously [5, 6] that an ac
magnetic ﬁ eld has a positive effect on the kinetics of
benzene vapor sorption by activated carbons, which is
manifested in an increase in the sorption capacity at low
The goal of our study was to examine the effect of
an ac magnetic ﬁ eld (MF) of industrial frequency on
the adsorption of vapors of organic solvents (ethanol,
benzene) by activated carbons with various porous
structure parameters and by composite sorbing materials
based on activated carbons having an inorganic (ash)
component with prescribed magnetoactive components.
The external treatment was effected with an ac
magnetic ﬁ eld of industrial frequency, with a strength of
5 kA m
, created by a solenoid.