Zeolitecarbon Sorbents Effective Regulators Of The Processes Of Migration Of Radionuclides In The Contaminated Soils
Zeolitecarbon sorbents effective regulators of the processes of migration of radionuclides in the contaminated soils
D. Shvets, E. Diyuk, N. Openko
Institute for Sorption and Problems of Endoecology NAS of Ukraine.
Kiev, Ukraine
The study of the physicochemical singularities of behaviour of radionuclides in the contaminated soils is necessary for understanding the processes of its redistribution between mediums, including vertical and horizontal migration. One of the ways of change of migrations capacity of radionuclides is introduction the sorbents in the soil.
A special attention in this problem is given to investigation of a role of sorbents, introducing in the soil to reduce a migration capacity of radionuclides or, on the contrary, making conditions for prompt removal of radionuclides from the soil.
In the work the study of influencing of natural, carbon sorbents and composite materials on its base on behaviour of radionuclides in a system soil – sorbent – plant was conducted.
The role of radioaccumulative plants on nature of reallocating of radionuclides in a system a soil - plant was studied at the presence of sorption materials of a various type.
It was shown, that the distribution number of radionuclides depends on a nature of sorbent and species of radioaccumulative plant.
It was found, that at the presence of natural and carbon sorbents the tendency of decrease of accumulative capacity of plants (fig. 1) is observed.
The opposite effect – increasing of accumulation degree of radionuclides by plants and the increase in biomass (fig.1, table) is observed in the case of zeolitcarbons composite materials.
The role of the various factors is analysed: acidities of a system, nature of paramagnetic centers of soils, role of humic compounds on a surface of highly dispersive clay minerals during fixation of radionuclides. The low or high mobility of radionuclides is explained from stands of a state of humic
compounds which are included in a mineral-organic system (a condensed, colloidal or dissoluble state).
Combining mineral matrix, conditions of forming of a mineral-organic system and species of plants it is possible to change migration capacity of radionuclides and to create systems with given ion - selective properties and sorption capacity. The further carrying out of the work in this direction will allow to develop technology of obtaining of organic-mineral sorbents for decontamination of soils polluted with radionuclides.
Fig. Influence of type of sorbents on distribution number of radionuclides Cs-137 (a) and on height (b) of plant.
Table 1. Influence of sorbents on the total mass and total activity of amaranth
Plant
Activity of green mass,
kBq/Kg
Total mass,
centner/hectare
Total activity of green mass (kBq/kg)/ hectare
K
Amaranth with
sorbent
2,3
3000-4000
850000
6,5
Amaranth without sorbent
1,3
1000
130000
1
References
1. D.Shvets, N.Openko, E.Diyuk. Carbon and carbonmineral sorbents in thе process of decontamination of the soils polluted by radionuclides. Abstracts International seminar Sorption methods and technogies in settlement of ecological and endoecological problems of the Chernobyl accident. July 14-17, 2000. Kiev-Ukraine, p.55-57.
2. V.V.Strelko, N.M.Openko, E.A.Diyuk, O.A.Glushachenko, D.I.Shvets. Carboncontaining sorbents in rhe processes of phytoremediation of radiopolluted soils. Ext.Abstr., 24th Biennial Conf. on Carbon, 1999, p.702-703.
3. V.V.Strelko & all. About a possibility of natural and carbon sorbents for decontamination of soil polluted with radionuclides. Abstracts., Cereco2000., The 3th International conference on carpathian Euroregion Ecology.Mishkolz-Hungary, p.47.
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