1070-4272/01/7411-1806$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 11, 2001, pp. 1806!1808. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 11,
2001, pp. 1753!1755.
Original Russian Text Copyright + 2001 by Makurin, Yuminov, Berezyuk.
AND ION-EXCHANGE PROCESSES
Sorption of Water-Soluble Copper(II) Compounds
Yu. N. Makurin, A. V. Yuminov, and V. G. Berezyuk
Ural State Engineering University, Yekaterinburg, Russia
Received August 9, 2000; in final form, June 2001
Abstract-Copper(II) sorption on clinoptilolite from aqueous solutions with different pH was studied.
The results were analyzed using the calculated distribution of water-soluble copper(II) species at different pH.
The best conditions of copper(II) sorption on clinoptilolite from aqueous solutions were determined.
Over a 33 4-thousand-year period copper is used for
production of implements, dishware, decorations, and
dyes. At present heat exchangers, vacuum apparatus,
pipes, and electric wires are produced from copper.
Copper alloys are applied as structural materials.
Copper compounds are used in production of glass
and enamels and in electroplating and ore enrichment.
They are also used as wood preservatives, catalysts,
The scale of application of copper and its com-
pounds gives rise to environmental problems. Copper,
like other heavy metals, plays a dual role in bio-
chemistry of plants and animals. On the one hand,
copper is involved in the metabolism, and on the other
hand, it is a toxic metal. The biological functions of
copper in cells are determined by its coordination
properties, possibility of reaction with oxygen, and
reversible reduction of copper compounds. Copper(II)
in a cell exists in the form of complexes with bio-
logically active compounds such as amino acids,
nucleic acids, biogenic amines, and hormones. The
average human consumption of copper with food is
235 mg daily. In the case of hard physical activity this
value increases to 7 mg daily. When the consumption
exceeds the daily demand, the organism is poisoned.
The toxicity is due to coordination of the S3H groups
of proteins and especially enzymes to copper(II) ions.
Copper compounds increase the permeability of mito-
chondrial membranes. Acute intoxication with copper
compounds is accompanied by hemolysis of erythro-
cytes and disorder of monoamine metabolism. As
a rule, a human being is poisoned with copper under
industrial conditions. However, poisoning with pot-
able water containing 444 mg l
of copper(II) cations
which are probably washed out from copper water
pipes has been described .
When the copper concentration in natural water
exceeds the productivity of the natural regeneration,
its concentration in potable water should be reduced
by special procedures. To decrease excess copper
content in tap water, natural sorbents including clino-
ptilolite are used. Clinoptilolite is a cheap and readily
available sorbent with a high capacity for copper .
We used clinoptilolite from the Kholin deposit
(Buryatiya). Its average composition is described by
the formula (K
O. The sili-
con/aluminum ratio ranges from 4.2 to 5.2. The cross
section of clinoptilolite openings is 0.40 0 0.55 nm;
the free pore volume is 0.34. The soprtion capacity
and stability of clinoptilolite in various media are
described in .
To determine the best sorption conditions, we
studied copper(II) sorption from aqueous solutions
with different pH, since the distribution of water-
soluble copper species exhibiting different sorption
properties strongly depends on pH. Copper(II) cations
are hydrolyzed in aqueous solution to form the fol-
lowing hydroxo complexes: [Cu(OH)]
, and [Cu(OH)
. The concentrations of
these species are denoted as C
, and C
instability constants are as follows [4, 5]:
= 7.0, pK
= 13.7, pK
= 17.0, pK
The fractions of copper species being in equilibri-
um in an aqueous solution are related to the instability
constant and pH by the following equations [6, 7]: