ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 7, pp. 1219−1228. © Pleiades Publishing, Ltd., 2015.
Study of Competitive Transport of Some Heavy Metal Cations
Across Bulk Liquid Membranes Containing Phenylaza-15-Crown-5
and Cryptand 222 as Carriers Using Flame Atomic Absorption
S. Tarahomi, G. H. Rounaghi*, and M. Chamsaz
Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad,
Azadi squ., 9177948974, Khorasan Razavi, Mashhad, Iran
*e-mail: email@example.com, firstname.lastname@example.org
Received July 17, 2015
Abstract—In this study, a competitive transport procedure was used for transport process of Cr(III), Cu(II),
Co(II), Cd(II), Ag(I), Pb(II), and Zn(II) metal cations across bulk liquid membrane (BLM) using phenylaza-
15-crown-5 and cryptand 222 as carriers and dichloromethane (DCM), chloroform (CHCl
), nitrobenzene (NB),
1,2-dichloroethane (1,2-DCE) and CHCl
–NB, DCM–1,2-DCE binary solvent solutions as extracting solvents.
Atomic absorption spectrometry was used for determination of the concentration of the studied metal cations in
source and receiving phases. The experimental results show that maximum transport rate is for silver(I) cation
in the presence of the other metal cations using phenylaza-15-crown-5 as carrier and no transport was observed
for the seven metal cations by cryptand 222 in all membrane systems. The effect of various parameters on the
transport process was investigated. The effect of solvent on the transport efﬁ ciency of silver(I) cation was found
to be in the order: NB > DCM > 1,2- DCE > CHCl
. The results also showed that the transport process of silver(I)
cation through CHCl
–NB and DCM–1,2-DCE bulk liquid membranes is sensitive to the solvent composition.
A non-linear relationship was observed between the transport rate of silver(I) ion and the composition of these
binary mixed solvents. The inﬂ uence of some fatty acids as surfactant in the membrane phase on the transport
of the metal cations was also investigated.
The text was submitted by the authors in English.
Researching liquid membranes has been developed
very rapidly after the ﬁ rst patent on liquid membrane
which was published in 1968 . In recent years,
a remarkable increase in the applications of liquid
membranes techniques in separation processes has
been observed in [2–5]. Moreover, their efﬁ ciency and
economic advantages contributed to a solution for some
important environmental problems, such as recovery of
precious metals, elimination of toxic heavy metals from
diluted solutions and permselective applications .
Since heavy metals are not biodegradable in natural
conditions, they tend to be accumulated in living
organisms causing various diseases and disorders .
Heavy metals pollution presents environmental, health,
and economical implications which have made them a
main subject for water protection . In particular, silver
is considered as a risk pollutant of natural waters in EU
legislation . Silver can enter the environment through
industrial water because it is often present as an impurity
in Cu, Zn, As, and Sb ores. So, the development of new
extraction techniques to remove the heavy metal ions like
silver(I) ion is of great importance [10, 11].
Liquid membranes can be classiﬁ ed as bulk liquid
membranes (BLM), supported liquid membranes
(SLM), and emulsion liquid membranes (ELM). Among
membrane technologies, the BLM technique represents
one of the liquid membrane techniques, in which a mobile
carrier governs the efﬁ ciency and selectivity of the liquid