ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2008, Vol. 53, No. 12, pp. 1972–1976. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © N.N. Basargin, E.R. Oskotskaya, P.E. Simakov, Yu.G. Rozovskii, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 12, pp. 2105–
2109.
PHYSICAL CHEMISTRY
OF SOLUTIONS
Zirconium Sorption by Chelating Polymer Sorbents
with an o,o'-Dihydroxyazo Analytical Functional Group
N. N. Basargina, E. R. Oskotskayab, P. E. Simakovb, and Yu. G. Rozovskiia
a Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences,
Staromonetnyi per. 35, Moscow, 119017 Russia
b Orel State University, Orel, Moscow
E-mail: basargin.nik@mtu-net.ru
Received April 24, 2008
Abstract—The complexing properties of new chelating polymer sorbents (CPSs) with an o,o'-dihydroxyazo
functionality and zirconium sorption on these sorbents were studied. Quantitative correlations were found
'
between pKOH of the analytical functional groups (AFGs) of sorbents and the stability of chelates (logβ ) in
order to understand the lows governing the effect of the structural features and acid–base properties of theAFGs
on zirconium chemisorption parameters. These correlations make it possible to quantitatively predict the phys-
icochemical parameters of sorbents and their chelates, synthesize them, and use CPSs for zirconium precon-
centration in analyses of natural and industrial objects.
DOI: 10.1134/S003602360812022X
Analysis of natural mineral assemblies containing
small zirconium amounts is a complex analytical task.
The existing basic spectrophotometric methods for zir-
conium determination do not always satisfy the con-
temporary requirements for detection limits and require
that zirconium be separated from associate elements.
Combination methods including preconcentration are
promising for improving analysis sensitivity. Chelating
polymer sorbents (CPSs) make it possible to accom-
plish individual or collective separation of a trace ele-
ment from large volumes of complex solutions,
decrease the detection limit, and eliminate or consider-
ably decrease the interference of macrocomponents,
thus improving the reliability and ruggedness of analy-
sis. The possibility to choose, synthesize, and use the
best CPSs for particular analytical purposes [1, 2]
seems promising.
EXPERIMENTAL
A zirconium stock solution was prepared by dis-
solving an exact weight of the metal in a mixture of
acids and was then diluted to prepare working solutions.An
aqueous solution of Arsenazo III (2,7-bis(2-arsonopheny-
lazo)-1,8-dihydroxynaphthaline-3,6-disulfonic acid)
was prepared by dissolution of an exact weight of the
chemically pure grade chemical in water. Chelating
polymer sorbents were synthesized in the Central
Chemical Laboratory of the Institute of the Geology of
Ore Deposits, Petrography, Mineralogy, and Geochem-
istry and purified using routine procedures to the chem-
ically pure grade. The AFG concentration ψ was moni-
tored by elemental analysis and the determination of
the sorption capacity of the sorbent (SCS). The degree
of AFG entry was within 0.2–0.4. The sorbents were
free of zirconium and impurity elements (40) as probed
by spectral analysis, except for magnesium (3 × 10–4%),
silicon (n × 10–3%), and iron (n × 10–3%).
pH was measured on an I-500 ionometer with 0.05
accuracy. The zirconium concentration of the solution
was monitored spectrophotometrically with Arsenazo
III (SF-46 spectrophotometer, λ = 665 nm, 2M HCl).
We have synthesized a new class of CPSs with o,o'-dihy-
droxyazo analytical functionality and substituents of
various electronic characters: Cl, SO3H, and NO2.
Sorption parameters (time, temperature, çÓpt and
pH50) were studied as in [2]. The stability constants of
CPS complexes with zirconium ions were determined
potentiometrically at (20 2)°C [3]. pH for 50% sorp-
tion (pH50) was determined graphically from R(%)–pH
curves, where R is the degree of sorption. The sorption
capacity of a sorbent was determined as the number of
mmoles (or milligrams) of zirconium sorbed per sor-
bent gram.
This study was undertaken to determine quantitative
correlations between the structure and acid–base prop-
erties of the analytical functional group (AFG) of the
sorbent, on the one hand, and the physicochemical
parameters of zirconium sorption, on the other, for syn-
thesizing and choosing sorbents with optimal physico-
chemical and sorption properties for use in analysis of
natural and industrial objects.
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