ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 3, pp. 430−435. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © S.D. Kolosentsev, V.N. Solovei, V.L. Kiseleva, E.A. Spiridonova, V.V. Samonin, 2015, published in Zhurnal Prikladnoi Khimii, 2015, Vol.
88, No. 3, pp. 424−430.
AND ION EXCHANGE PROCESSES
Effect of Nitrogen- and Sulfur-containing Modifying
Additives on Porous Structure and Sorption Properties
of Carbon Adsorbents
S. D. Kolosentsev, V. N. Solovei, V. L. Kiseleva, E. A. Spiridonova, and V. V. Samonin
St. Petersburg State Technological Institute (Technical University), Moskovskii pr. 26, St. Petersburg, 190013 Russia
Received March 31, 2015
Abstract–Modiﬁ ed nitrogen- and sulfur-containing sorbent were produced on the basis of industrial activated
carbons by their thermal treatment with preliminary impregnation with thiourea and ammonium rhodanide. It
was found tat the modiﬁ cation affects the porous structure, surface physicochemical properties, and sorption
characteristics of carbon sorbents. The increase in the protection duration of thiourea-modiﬁ ed carbons by 67%,
compared with the starting carbons, at a relative air humidity of 70% is illustrated.
One of effective ways to purify gaseous media is by
adsorption on activated carbons (ACs) . In most cases,
contaminating components are removed from gases at
their high humidity, when the effect of water vapor on the
sorption of microscopic admixtures of organic substances
is of key importance. This primarily refers to substances
poorly sorbed under standard conditions (methanol,
acetone, methylene chloride, etc.) and also to well-
sorbed compounds (petroleum products, large organic
molecules, benzene and its derivatives, etc.) at their
low concentrations. Under these conditions, a sorbent
should predominantly absorb a contaminant, rather than
water, which is governed by the hydrophobicity of the
To impart speciﬁ c, including hydrophobic, properties
to ACs, various heteroatoms are introduced into their
structure [2–5]. The best positive results have been
obtained in the surface modiﬁ cation with nitrogen because
nitrogen-containing groups (pyrrol, pyridine, amine)
induce a positive potential to a greater extent [6–9].
This can be done by impregnation of ACs with modiﬁ er
solutions or by introduction of a modifying additive in
the course of their synthesis.
The goal of our study was to determine the possibility
and promise of introducing heteroatoms into the AC
structure of ACs in the course of their modiﬁ cation with
nitrogen- and sulfur-containing compounds, with the
subsequent ﬁ xation of heteroatoms in the carbon structure
by thermal treatment in an inert medium, and to study
the porous structure and sorption properties of the thus
We used as starting samples for their subsequent
modiﬁ cation the following brands of industrial activated
carbons: Norit G 1220 EXTRA, Filtrasorb TL830, and
AG-5 (Table 1).
Preliminarily dried starting samples were impregnated
with solutions of modiﬁ ers of organic (thiourea) and
inorganic origin (ammonium rhodanide) with mass
fractions of 2.0, 5.0, and 15.0% in terms of sulfur and 0.9,
2.3, and 6.8% in terms of nitrogen, respectively.
The activated carbons were impregnated with
modifying agents under normal conditions in the course
of 24 h. The amount of an impregnating solution was
calculated on the basis of the total pore volume of a
starting AC, presented in Table 1.
The samples were thermally treated in the steady-state
mode in a stainless steel retort in a ﬂ ow of nitrogen. The