Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 7, pp. 1046−1051.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © N.A. Yushketova, V.A. Poddubny, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 7, pp. 1078−1083.
OF SYSTEMS AND PROCESSES
Evaluation of Sorption Efﬁ ciency Coefﬁ cients in Passive
Sampling of Nitrogen(IV) Oxide
N. A. Yushketova and V. A. Poddubny
Institute of Industrial Ecology, Ural Branch, Russian Academy of Sciences, Yekaterinburg, Russia
Received August 25, 2011
Abstract—Nitrogen(IV) oxide concentration in the atmospheric air was measured by passive sampling with two
sorbent solutions in order to evaluate their efﬁ ciency in absorption of NO
. A model taking into account the sorp-
tion efﬁ ciency of the sorbent solutions used was suggested.
A passive sampler is a device for taking samples of
contaminants with a special absorbing agent (a support
impregnated with a sorbent solution or a solid absorbent)
via molecular diffusion without forced air pumping
[1, 2]. The contaminants accumulate in the sampler
via physical of chemical sorption. This method makes
it possible to estimate contaminant concentrations
averaged over the sampling period, which may be as
long as several hours to several weeks. The passive
sampling method is distinguished by simplicity of use,
small size of sampling devices, and independence from
electric power sources and ﬁ nds wide application in
scientiﬁ c and applied studies .
Numerous laboratory and full-scale measurements of
concentration, performed by passive sampling,
demonstrate that the accuracy of this technique varies
between cases when different sorbents are used [4, 5].
According to ,the discrepancy between results of
parallel measurements with passive samplers using
different sorbents reached a value of 200%, and the
difference between the passive sampling data and results
of control measurements varied within the range from
–50 to +30%.
Nitrogen(IV) oxide is most frequently absorbed
in passive sampling with solutions based on
triethanolamine (TEA) and potassium iodide [3, 4]. In
the ﬁ rst case, TEA solutions in water or acetone with a
triethanolamine content of 10–50 vol % are used [3, 4].
Data on the accuracy of NO
measurements with TEA
solutions are contradictory. There have been indications
that the agreement with results of control measurements
is good [4, 5], whereas other authors report a substantial
systematic over-  or underestimation  of results.
The overstating of the sampling results is attributed
to the inﬂ uence of external factors [2, 4, 6], such as
wind and presence of other contaminants that can be
absorbed by the sorbent solution. The understating of
the results of passive sampling is attributed to partial
disintegration of the chemisorption reaction product in
sampling (decrease in the accumulated mass, instability
of the reaction product) and to incomplete course of the
chemisorption reaction .
In sampling with potassium iodide, the absorbing
solution also includes ethylene glycol, sodium arsenate,
and methanol  or a sodium iodide solution with
sodium hydroxide in methanol is used . Tests of
sorbents based on potassium iodide did not reveal any
severe shortcomings. However, based on the number of
foreign publications, we can conclude that this sorbent
is used less widely than triethanolamine solutions.
The goal of our study was to perform a set of test
measurements of the NO
concentration by passive
sampling with absorbing solutions based on TEA and
potassium iodide and to evaluate their efﬁ ciency.