ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 6, pp. 915!919. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + B.M. Kats, R.M. Dlubovskii, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 6, pp. 938!942.
AND ION-EXCHANGE PROCESSES
Selective Sorption of Water Vapor from Gas Mixtures
, NO, and CO on KU-2 Sulfonic
Styrene Cation Exchanger in Different Ion Forms
B. M. Kats and R. M. Dlubovskii
Mechnikov National University, Odessa, Ukraine
Received August 2, 2006; in final form, March 2007
Abstract-Sorption of water vapor and some acid gases (H
, NO, and CO) on KU-23-15/100
macroporous sulfonic cation exchanger in different ion forms and on commercial KSM silica gel and NaX
artificial zeolite was studied under equilibrium and dynamic conditions. The equilibrium isotherms of water
vapor sorption were measured for all the adsorbents examined. The mechanism of water sorption on the sul-
fonic cation exchanger was discussed.
Adsorption and gas-chromatographic properties of
macroporous ion exchangers are due to their high
porosity, i.e., to the presence of macro- and meso-
pores permeable to molecules of gaseous adsorbates
[1, 2]. These molecules can be irreversibly sorbed
on the internal surface of ion exchanger grains.
The sorption is caused by specific interaction of gases
with the functional groups of the ion exchanger .
Selective sorption of a gas can be provided by intro-
duction of appropriate functional groups into the sor-
bent. For example, the sorption capacity of particular
ion forms of KU-23 sulfonic action exchanger for
some gases (e.g., ammonia and amines [4, 5]) is fairly
high, with the sorption being mainly determined by
the type of the exchangeable cation.
The aim of this study was to examine the possibil-
ity of using KU-23 macroporous sulfonic cation ex-
changer as selective desiccant for gas mixtures con-
taining hydrogen sulfide and oxides of sulfur, nitrogen,
and carbon. These substances are the main atmospher-
ic pollutants whose detection on gas-analyzers is com-
plicated by the interfering effect of water vapor pres-
ent in a gas3air mixture (GAM) [6, 7].
We used commercial KU-23-15/100 macroporous
sulfonic styrene cation exchanger (Azot Production
Association, Cherepovets, Russia) . The static
exchange capacity of the sample for 0.1 M NaOH,
determined by the procedure described in , was
3.8 mg equiv g
. We studied the sulfonic cation ex-
changer in the hydrogen, sodium, copper, and cobalt
forms. The hydrogen form was prepared by successive
washing of the initial sample with 5% solutions of
NaOH and HCl to their constant concentration in
the filtrate and then with distilled water to the neutral
reaction. The salt (sodium, copper, and cobalt) forms
were prepared by washing of the hydrogen form of
the cation exchanger with a 5% solution of the appro-
priate metal salt until the concentration of the metal
ion in the solution became equal to that in the filtrate.
Commercial desiccants of various gases (artificial
NaX zeolite and KSM silica gel)  were studied
We used as adsorbates gaseous H
NO, and CO prepared from analytically pure grade
chemicals and purified by know procedures. Twice
distilled water was used to produce the water vapor.
The equilibrium sorption was studied with a vacu-
um unit equipped with a MacBain3Bakr quartz spring
balance . The sorbent was placed in the unit and
kept at 293 K and a residual pressure of 0.133 Pa until
the sample weight became constant, i.e., the sorption
equilibrium was attained. Prior to the experiment,
NaX zeolite was kept at 620 K for 2 h, and KSM sil-
ica gel at 570 K for 2 h. The measurements were per-
formed with the aid of a cathetometer. The water
vapor pressure gradually increased to p/p