Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 10, pp. 1840−1844.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
I.V. Sheveleva, A.N. Kholomeidik, A.V. Voit, N.P. Morgun, L.A. Zemnukhova, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82,
No. 10, pp. 1688−1692.
INORGANIC SYNTHESIS AND INDUSTRIAL
Removal of Metal Ions with Rice Husk-Based Sorbents
I. V. Sheveleva, A. N. Kholomeidik, A. V. Voit, N. P. Morgun, and L. A. Zemnukhova
Institute of Chemistry, Far East Branch, Russian Academy of Sciences, Vladivostok, Russia
Far East State University, Vladivostok, Russia
Received December 22, 2008
Abstract—Sorption of metal ions from solutions of individual salts and their mixtures by rice husk-based sorbents
was studied. The sorption properties of the rice husk were examined in relation to its modification conditions.
As known, transition metal ions belong to most
hazardous ecotoxicants adversely affecting the environ-
ment and human health.
Removal of transition metal ions from wastewater
before discharging into water bodies, as well as in
water treatment applications, still remains a problem to
be solved in the optimal way. Today, heavy metal ions
are most often removed from wastewater by chemical
methods, speciﬁ cally, precipitated as poorly soluble
compounds to be further isolated.
Efﬁ cient treatment can be achieved with sorption
methods in which the residual concentrations of different
pollutants in water do not exceed in some cases the
maximum permissible concentrations . Heavy metal
ions can be removed by sorbents based on both synthetic
and natural materials: various fibrous sorbents ,
modiﬁ ed and technical lignins , gelatin-immobilized
complexes of heavy metals , clays , silica gels ,
and modiﬁ ed granulated carbon adsorbents . There
has recently been increasing interest in natural sorbents.
Raw material for them can be found in wood-processing
wastes: chips, lignin, bark [3, 8], cellulose , and food-
processing waste: chitin-containing materials yielded by
integrated processing of biogenic raw materials (krill,
shrimp, crab) , as well as in pits and integuments
(soybean meal , husks, shells, and hulls of agricultural
Deoiled rice bran can be used for removal of
chromium, copper, and zinc ions , and rice husk,
of strontium, cadmium, nickel, lead, zinc, chromium,
cobalt, and aluminum ions from solutions. Thus, rice
manufacturing waste products as such are suitable as
low-cost sorbents for treating various liquid media.
Also, rice husk can be used for preparing carbonaceous,
siliceous, or phosphorous materials with high sorption
characteristics [15, 16].
Here, we elucidated the suitability of rice husk
processing products as sorbents for removing Fe(III),
Cu(II), Cd(II), and Pb(II) ions from aqueous solutions.
As sorbents we used untreated rice husk (particle size
no less than 2 mm) collected in Primorsk and Krasnodar
krais, which was rinsed with water and dried at 105°C
(sample no. 1), and the rice husk processing products
(sample nos. 2–4) prepared by the schemes described
in [16, 17] (Table 1). The samples prepared by acid and
alkaline hydrolysis of the initial rice husk were thoroughly
rinsed with distilled water till neutral pH was reached.
The content of silicon in the samples was determined
gravimetrically , and that of carbon, by the procedure
described in . The speciﬁ c surface area S
of the sorbent was estimated by the standard technique
 with Methylene Blue (Table 1).
Sorption was carried out under static conditions
(all analytically pure-grade) solutions with metals
concentrations within 5–300 mg l
. The changes in pH
of the solutions, speciﬁ cally, from 5.73 to 5.55 for Cu(II),
from 6.02 to 5.95 for Cd(II), from 6.10 to 5.65 for Pb(II),