1070-4272/01/7402-0253 $25.00 C 2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 2, 2001, pp. 253!258. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 2, 2001,
Original Russian Text Copyright + 2001 by Shashkova, Rat’ko, Panasygin, Mil’vit, Bondareva.
OF CHEMISTRY AND TECHNOLOGY
Deironing of Water with Natural Carbonate-containing Tripoli
I. L. Shashkova, A. I. Rat’ko, A. S. Panasygin, N. V. Mil’vit, and N. V. Bondareva
Institute of General and Inorganic Chemistry, Belarussian Academy of Sciences, Minsk, Belarus
Belarussian State Polytechnical Academy, Minsk, Belarus
Received September 15, 1998; in final form, March 2000
Abstract-The possibility of using natural carbonate-containing tripoli for water deironing was studied.
Factors are considered determining the efficiency of tripoli in Fe(III) absorption.
Siliceous rocks constituted by various finely dis-
perse opal-crystobalite formations (opokas, diatomites,
tripolis) occur in nature either in pure form or with
varied content of an associated component-most
frequently of the carbonate-clay type . The content
of calcium carbonate in rocks of this kind is 0360%,
and that of clay, 0315%, for different deposits.
In contrast to purely siliceous rocks, which are
raw materials serving for various purposes and having
their traditional areas of application (e.g., in manufac-
ture of construction cement [1, 2]), carbonate-clay
materials have not found wide use.
Large deposits of carbonate tripoli have been dis-
covered in many regions of Belarus, Lithuania, and
Russia. In this connection, it is of current interest
to reveal the possibility of their use in the national
With account of the ability of the carbonate com-
ponent to absorb ions of heavy and non-ferrous me-
tals from aqueous solutions , carbonate tripolis
show ecological promise.
Compared with carbonates, carbonate-containing
silicas are characterized by more developed porous
structure and lower solubility , and also by ability
to form strong granules , and, therefore, their use
in water purification seems to be more promising than
that of carbonates.
Previously, the high efficiency of carbonate-con-
taining tripolis in recovery of a number of heavy metal
ions: Cr(III), Pb(II), Zn(II), and Cu(II), has been de-
monstrated [9, 10]. The present communication re-
ports the results obtained in studying their efficiency
in deironing. A search for new high-efficiency ma-
terials for deironing of ground water and wastewater
is an important task .
The experiments were done with a tripoli contain-
ing 43.5% calcium carbonate, with its aqueous extract
characterized by pH 8.6.
A representative sample of
a natural carbonate tripoli and four its thermal modi-
fications obtained by calcination in air at 500, 600,
700, and 800oC (designated as tripoli-500, tripoli-600,
etc.) were used in the study.
The absorption of Fe(III) ions under static condi-
tions from 0.00130.1 N nitrate solutions with pH
1.732.3 was studied at 15320oC at liquor ratio M =
1 : 125 [M = s : l, where s denotes the mass of solid
sorbent (g), and l, the volume of liquid phase (ml)].
The experimental procedure was as follows: 25 ml
of a solution was poured over 0.2 g of sorbent
(0.0930.25-mm fraction) and the mixture was kept for
1 day with periodic stirring. In studying the kinetics
of the process, the experimental technique was sim-
ilar, but the time of contact between the solution and
the solid phase was varied between 10 min and sev-
eral days. The solution was separated from the solid
phase and the residual content of iron in the filtered
solution was determined by complexometric titration
or atomic-absorption spectrometry.
The solid phase was washed with water, dried in
air, and subjected to X-ray phase analysis (DRON-2.0
The variation of the solution pH during sorption
was monitored with an EV-74 ion meter.
Stal’noe deposit, Mogilev oblast, Belarus.