ISSN 1070-4272. Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 3, pp. 363!366. + Pleiades Publishing, Inc., 2006.
Original Russian Text + E.A. Zauer, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 3, pp. 370 !373.
AND ION-EXCHANGE PROCESSES
Sorption of Mercury(II), Zinc(II), and Iron(III) Thiocyanate
Complexes on AV-17 Anion Exchanger and KU-2
Cation Exchanger Modified with Rhodamine Zh
E. A. Zauer
Volgograd State Engineering University, Volgograd, Russia
Received March 25, 2005
Abstract-Sorption of anionic mercury(II), zinc(II), and iron(III) thiocyanate complexes on KU-2 cation
exchanger modified with Rhodamine Zh and on AV-17-8 strongly basic anion exchanger were studied in
relation to the concentration of SCN
ions and solution pH. Optimal conditions of sorption of metal complexes
from dilute solutions were found.
Complex formation is widely used to increase the
selectivity of metal ion sorption. Both usual and
chemically and surface-modified ion exchangers are
used as sorbents [1, 2].
The data on sorption of complex ions with usual
and modified ion exchangers are lacking, although
they are necessary to optimize sorption preconcentra-
tion and separation of elements and to develop tech-
nologies of industrial waste management. For in-
stance, sorption of mercury(II) halide complexes with
AV-17 anion exchanger was studied in . Sorption
of zinc complex ions from chloride solutions on vari-
ous anion exchangers is described in . Studies
on sorption from mixtures of complexes are very few.
In this study, we examined the kinetics of sorption
of mercury(II), iron(III), and zinc(II) thiocyanate
anionic complexes on AV-17-8 strongly basic anion
exchanger and on KU-2 strongly acidic sulfonic
cation-exchange resin modified with a basic dye,
Rhodamine Zh (RZh).
The initial solution of iron(III) was prepared from
ferric ammonium sulfate  and standardized com-
plexometrically with sulfosalicylic acid . A mer-
cury(II)-containing solution was prepared from mer-
cury sulfate  and standardized by complexometric
back-titration with Eriochrome Black T indicator .
A solution containing Zn(II) was prepared by dissolv-
ing metallic zinc (chemically pure grade) in hydro-
chloric acid . The working solutions were prepared
by dilution of the initial solutions with distilled water.
AV-17-8 anion exchanger in the chloride form was
prepared as in .
To obtain modified KU-2 cation exchanger, the ini-
tial KU-2 resin in the hydrogen3salt form prepared as
in  was stored in 0.2% aqueous solution of Rhoda-
mine Zh for 24 h and then separated by filtration,
washed with distilled water, and dried. Modification is
the ion-exchange reaction
It is known that basic dyes form ionic associates
with halide and thiocyanate complexes of certain
metal ions insoluble in water but soluble in organic
solvents (e.g., toluene). This property of dyes is
widely used in analytical chemistry for extraction-
photometric determination of elements, including
mercury(II) and zinc(II) [8, 9].
In this study, ionic associates of elements under
consideration were obtained in the phase of the sorb-
ent modified with Rhodamine Zh but not in a solution,
and potassium thiocyanate was used as a complexing
To study the sorption kinetics, a 0.50+ 0.05-g por-
tion of the sorbent was introduced into 100 cm
a solution containing zinc, iron, or mercury after addi-
tion of a 25% aqueous solution of potassium thiocya-
nate. The mixture was stirred with a magnetic stirrer
for definite time, and the sorbent was separated,
washed with distilled water, and dried.