these colloidal substances absorb ions of heavy metals and radionuclides, which leads
to serious human diseases. Therefore, iron ions content in drinking water should not
exceed 0.3 mg/dm
3
[5].
There are various other methods for iron ions removal from ground-water, for
example, oxidation with oxidizing agents such as chlorine and potassium
permanganate [6], supercritical fluid extraction [7], bioremediation [8], treatment with
limestone [9, 10]. activated carbon and other filtering materials [11], ion-exchange
method [12, 13], electro-coagulation method.
The search for new, more sophisticated and economically feasible methods is one
of the main areas for the development of sewage treatment technologies. A promising
method for removal heavy metals from aqueous solutions can be biosorption, which
involves the use of inexpensive effective sorbents based on waste or by-products of
plant material processing. A large amount of plant waste that needs to be recycled is
produced every year all over the world. One of the effective ways to dispose of such
waste is their application as biosorbents. From literature it is known that it is possible
to use waste of wood and pulp and paper industry, as well as agriculture as biosorbents.
Domestic vegetal wastes from agriculture and food industry can also be considered as
effective sorbents of heavy metals and radionuclides. The main advantages of using
such materials as sorbents are: annual renewal, availability, cheapness and ease of
disposal [14].
In the case of acidic waste, various carbonate-containing materials can be used
for neutralization, but the disadvantage of this process is the adhesion of the filtering
material. It is expedient to use aeration methods to improve the productivity and
efficiency of the process. It is promising to use electrolyzers, since this method is quite
simple and economical.
In literary sources, studies on the possibility of introducing precipitates formed
during water purification into various types of building materials, despite the content
in the sediments of heavy metals were carried out. Thus, in order to dispose of
sediments formed during water purification and containing heavy metal ions, it is
rational to use cements with active mineral additives, slag cements, mixed binders and
articles thereof [15, 16].
Сonsidering this, it is important to find new reagents and methods that will ensure
the high efficiency of the removal of heavy metal ions from aqueous solutions with
subsequent disposal of formed sediments.
Removal of iron ions from water with biosorbents. In natural waters (surface
and artesian), iron ions can be in two forms: oxidation of Fe
2+
, Fe
3+
and in a complex
form (Fig. 1). It can be inorganic and organic compounds that are found in water in
dissolved, colloidal and suspended states. The appearance of iron ions in artesian
waters, primarily, is occurred due to the dissolution of iron-bearing rocks. In the
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