ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 4, pp. 652−656. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © A.I. Fomenko, L.I. Sokolov, 2015, published in Zhurnal Prikladnoi Khimii, 2015, Vol. 88, No. 4, pp. 622−626.
AND ION EXCHANGE PROCESSES
It is known that the main nutrient substance limiting
the growth of plants in many fresh water basins are
phosphates. The excess of phosphates in surface water
appears mostly due to the direct runoff of surface water,
residential sewage, and production wastewater from
industrial plants. The conventionally used techniques
of biological dephosphation of wastewater of this kind
fail to always provide the necessary quality of puriﬁ ed
wastewater in conformity with the related regulations
. The degree of puriﬁ cation of biologically puriﬁ ed
wastewater can be raised by introduction into the
technological scheme of the stage of a polishing
treatment, mostly performed by chemical precipitation of
phosphates with aluminum and iron salts, and also lime
serving as coagulants [2–4]. However, these polishing
treatment methods have limited applicability, which
is due to the expenditure of reagents and formation of
highly humid precipitates whose utilization is difﬁ cult.
There have been reports concerned with the possibility
of puriﬁ cation of aqueous solutions to remove phosphate
ions under particular process conditions by less expensive
and more ecologically friendly sorption techniques.
Therefore, a search for technologically and economically
effective sorbents for deep puriﬁ cation of wastewater to
remove phosphates is a topical task.
Of high interest are sorbents produced from readily
available technogenic raw materials and, in particular,
wastes formed in processing of materials of plant origin
[8–10]. These materials are distinguished by low cost,
which makes them expendable and simpliﬁ es their use.
Equilibrium-kinetic characteristics play an important
role in assessing their applicability as sorbents and
determining the sorption conditions.
In this study, we examined the kinetics of the sorption
process and sorption characteristics of wood ash produced
in the technological cycle of manufacture of wood-plate
materials in burning of wastes formed in processing of
crushed wood with respect to phosphate ions with the
aim of its further use for deep puriﬁ cation of wastewater
to remove phosphates.
Phosphate ions were sorbed from aqueous solutions
with wood ash represented by a mixture of fractions with
grain sizes of 0.08–2.0 mm. The chemical composition
of the wood ash samples under study was determined by
the following relative amounts of components (wt %):
2.31, CaO 38.68, MgO 12.85, Fe
O 2.58, Na
O 0.45, SO
0.4, and calcination loss 17.11. The granulometric and
chemical composition of the wood ash samples taken
for experiments was studied by normative methods in
conformity with the methodological recommendations
established for determining the component composition
of mineral raw materials [11–14].
A Study of Sorption of Phosphate Ions
from Aqueous Solutions by Wood Ash
A. I. Fomenko and L. I. Sokolov
Vologda State University, ul. Lenina 15, Vologda, 160000 Russia
Received March 4, 2015
Abstract—Possibility was studied of performing sorption puriﬁ cation of aqueous solutions to remove phosphate
ions, with wood ash formed in burning of wastes formed in processing of crushed wood serving as a sorbent.
Kinetic dependences of the sorption process were examined and sorption characteristics of wood ash with respect
to phosphate ions were determined.