1070-4272/05/7811-1827C2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 11, 2005, pp. 1827!1831. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 11,
2005, pp. 1859!1863.
Original Russian Text Copyright + 2005 by Shashkova, Mil’vit, Rat’ko.
AND ION-EXCHANGE PROCESSES
Selective Sorption of Fe(III) Ions from Ni(II)!Fe(III) Mixtures
I. L. Shashkova, N. V. Mil’vit, and A. I. Rat’ko
Institute of General and Inorganic Chemistry, Belarussian National Academy of Sciences, Minsk, Belarus
Received June 15, 2005
Abstract-Selective recovery of Fe(III) ions from two-component nitrate solutions of Fe(III) and Ni(II) with
synthetic nickel phosphate, natural chalk, and natural tripoli were studied. The mechanism of selective action
of chemisorbents was considered, and high efficiency of the materials considered was demonstrated.
Ion exchange and chemisorption are traditionally
used to sorb metal ions. In the latter case, sorbents
chemically bind metal ions. Unlike ion exchange,
chemisorption is characterized by substantial selec-
The capability of inorganic substances for selective
chemisorption is caused by formation of new chemical
compounds with lower Gibbs energy as compared to
the initial state (e.g., less soluble compound), possibil-
ity of redox reactions, and other effects .
Poorly soluble sulfides, hydroxides, carbonates,
and phosphates of some rare-earth and other bivalent
metals exhibit chemisorption power with respect to
heavy and nonferrous metals. The compounds formed
in the process are less soluble than the initial com-
pounds . The chemisorption power depends on
a number of factors; the major factor is the difference
between the solubility products of the initial sorbent
and compound formed, DSP.
A sorbent suitable for chemisorption of definite
ions from mixtures can be found by considering the
solubility series of phosphates, carbonates, and hy-
droxides of double and triple-charged metals.
Chemisorption can be a promising procedure for
selective recovery of some nonferrous metal ions
from two- and multicomponent solutions.
After deposition of nonferrous metal hydroxides
from electroplating waste, filtrates (aqueous solutions
containing from 2 to 25 g l
of alkali, alkaline-earth,
and nonferrous metal salts) are formed; with the non-
ferrous metal fraction being 536% of the total metal
content . The composition of filtrates depends on
the waste processing technology. Such solutions may
contain ions of 2310 nonferrous metals in amounts
from 20330 to 6003800 mg l
Dilute solutions containing nonferrous metals are
concentrated using nonselective and selective ion-
exchange materials. In the first case, all above metals
and in the second case, only nonferrous metals are
sorbed . In contrast to selective ion-exchange ma-
terials, selective chemisorbents can be used not only
for group concentration of nonferrous metals, but
also for their separation.
In this study, we used synthetic nickel(II) ortho-
phosphate and natural carbonates for selective sorp-
tion of iron(III) from binary solutions containing
Fe(III) and Ni(II). Two-component dilute Fe
aqueous solutions are formed during processing waste
from nickel3iron battery electrodes  and from elec-
trolytic baths for iron nickel-plating.
O was synthesized as
in . A hydrochloric (pH 5) solution of (NH
(5 g) in 100 ml of water was added dropwise to a
solution of NiCi
O (100 g) in 100 ml of water
with stirring at room temperature. The light green pre-
cipitate obtained was stored under the mother liquor
for 2 h, filtered through a B1uchner funnel, washed
several times with distilled water, and dried in air and
then over P
Tripoli with 30365 wt % CaCO
were taken as natural sorbents. Chalk and tri-
poli were ground, and the fraction <0.025 mm was
sifted out before use.
The iron(III) sorption from two-component solu-
tions [iron(III) and nickel(II) nitrates] was studied
Tripoli from Stal’noe deposit (Mogilev oblast) and chalk from