1070-4272/04/7705-0739C2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 5, 2004, pp. 739!744. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 5,
2004, pp. 743!748.
Original Russian Text Copyright + 2004 by Anurova, Klushin, Mukhin, Myshkin, Anurov, Suare.
AND ION-EXCHANGE PROCESSES
Adsorption of Hydrocarbon Vapors on Activated Carbons
Obtained from Vegetable Raw Materials
T. V. Anurova, V. N. Klushin, V. M. Mukhin, V. E. Myshkin,
S. A. Anurov, and M. A. Suare
Mendeleev Russian University of Chemical Engineering, Moscow, Russia
Received July 22, 2003; in final form, December 2003
Abstract-The equilibrium adsorption of vapors of benzene, toluene, o-xylene, and gasoline in the tempera-
ture range 253100oC and adsorbate content of 0.0131.80 vol % on activated carbons obtained from plum
stones and shells of peanut, walnut, and coconut was studied. The effect of temperature on the adsorption
properties of the absorbents were analyzed. The isosteric heats of adsorption were calculated.
The protection of the atmosphere from pollution is
an important and complicated environmental problem.
Among the most global contaminants discharged into
the atmosphere are various hydrocarbons. The most
dangerous of these are, because of their prevailing
mass, vapors of volatile organic solvents and light
petroleum products, such as benzene, toluene, xylenes,
gasolines, etc. The negative consequences of dis-
charge of these toxic compounds are well known .
However, the economical factor, associated with the
loss of valuable chemical compounds so much needed
by modern industry, is to be taken into account in
addition to the environmental aspect of the problem.
According to the available estimates , the annual
Russia’s discharge from only stationary industrial
sources is 1.6 million tons of volatile organic com-
pounds and 2.6 million tons of other hydrocarbons
even during the period of recession.
The diversity of conditions under which organic
solvents and motor fuels are vaporized requires that
different methods should be developed for their re-
covery. Among the rather wide variety of methods of
this kind , processes of carbon-sorption purification
are virtually unrivaled in processing of flows with
relatively low content of these components. However,
their use is only economical if low-cost and readily
available carbon adsorbents can be used.
A technique for obtaining activated carbon from
vegetable wastes in the form of plum stones and
nutshells has been developed. This method yields
microporous adsorbents with an effective half-width
of micropores of 0.53 0.7 nm, which is comparable
with the size of molecules of the organic compounds
mentioned above. This suggests that these adsorbents
can serve as rather active absorbents of hydrocarbons
from vapor3gas mixtures.
To confirm the efficiency of this approach, it is
necessary to study the adsorption properties of these
carbons with respect to a number of characteristic
hydrocarbons and light petroleum products. This was
the aim of our study.
As adsorbents served activated carbons obtained by
carbonization in a nitrogen atmosphere of plum stones
(PS) and shells of peanut (SP), walnut (SW), and
coconut (SC) at 800oC for 1 h, followed by steam3gas
activation of the carbon matrices under similar tem-
perature and time conditions. The carbonizates of PS
and SW were oxidized with water vapor, and those of
SP and SC, with a nitrogen3oxygen mixture (2 vol %
). As reference were chosen activated carbons of
SKT and ART-1 brands, which are recommended as
adsorbents for catching vapors of organic solvents
[3, 4]. The main technical characteristics of the carbon
adsorbents are listed in Table 1.
As adsorbates were used benzene, toluene, o-xyl-
ene, and gasoline (motor fuel of the AI-95 brand).
A number of physical constants of these hydrocarbons
are listed in Table 2 . It is difficult to specify the
physical properties of gasolines because they are mix-
tures (boiling out at 403195oC) of cyclic (20365%),
aromatic (2312%), saturated (25380%), and un-
saturated (132%) hydrocarbons whose content in the
final product is determined by the composition of the