ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 3, pp. 388−393. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © A.V. Perﬁ l’eva, V.A. Brodskii, V.I. Il’in, V.A. Kolesnikov,
2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89, No. 3, pp. 334−340.
AND ION EXCHANGE PROCESSES
Effect of the Composition of the Medium and Electroﬂ otation
Processing Parameters on Extraction Efﬁ ciency
of Chromium(III) Dispersed Phase
from Aqueous Solutions
A. V. Perﬁ l’eva*, V. A. Brodskii, V. I. Il’in, and V. A. Kolesnikov
Mendeleev University of Chemical Technology of Russia, Miusskaya pl. 9, Moscow, 125047 Russia
Received March 6, 2016
Abstract—Inﬂ uence exerted by the composition of the medium (solution pH, ionic composition, presence of
ﬂ occulants and surfactants), physicochemical properties of the dispersed phase (particle size, electrokinetic
potential), and technological parameters of the electroﬂ otation process (volume current density, magnetic treat-
ment, solution temperature) on the efﬁ ciency of the electroﬂ otation extraction of poorly soluble chromium(III)
compounds from aqueous solutions was studied. It was shown that the extraction efﬁ ciency directly depends on
the composition of the medium, which determines the physicochemical properties of poorly soluble chromium(III)
compounds, and on the size of particles and their minimum surface charge. The optimal technological parameters
of the electroﬂ otation process are suggested.
The decrease in the adverse effect of industries on
the environment is associated with numerous factors, but
the most important of these is the effective wastewater
puriﬁ cation to remove toxic metal ions. Because of
the high toxicity of chromium compounds, chromium-
containing wastewater occupies a particular place among
industrial wastewaters containing noxious contaminants.
Wastewater contaminated with compounds of hexa-
and trivalent chromium are formed in manufacture of
chromium salts (mono- and bichromates, chromium
anhydride, etc.), inks, dyes, white iron, in galvanic shops,
leather, textile, woodworking, pyrotechnic, and other
In galvanic shops, wastewater contaminated with
chromium-containing compounds is formed in chemical
and electrochemical processing of metals and alloys of
these. Hexavalent chromium compounds are contained
in wastewater formed in the following cases: washing
of chromium-plated articles; chemical etching and
surface passivation of parts made of ordinary, zinc-
plated and cadmium-plated steels, and copper alloys;
electropolishing of steel articlesl and electrochemical
anodization of aluminum parts .
In dyeing and ﬁ nishing shops, chromium-containing
wastewater is formed in production of fabrics, carpets,
and yarn; and in leather industries, in tanning processes
and in dyeing of leather, fur, fabrics, and various ﬁ bers.
Wastewater from these industries may contain, in
addition to hexa- and trivalent chromium compounds,
also chlorides, sulfates, calcium, mineral acids, organic
compounds, and suspended substances.
The conventional scheme for puriﬁ cation of chromium-
containing wastewater is based on the reduction of
hexavalent chromium to trivalent compounds by chemical
and electrochemical methods, followed by isolation of
poorly soluble compounds in the form of a dispersed
phase and its separation from water [2–4].
The standard reducing agents for chromium(VI)
from wastewater formed in galvanic shops are iron(II)
(and other compounds
of tetravalent sulfur), FeSO
, steel shavings, sodium