Retardation capacity of organophilic bentonite for anionic fission products.
J Contam Hydrol
; 47(2-4): 255-64, 2001 Feb.
Article
em En
| MEDLINE
| ID: mdl-11288581
ABSTRACT
Sorption and diffusivity of iodide and pertechnetate (I- and TcO4-) on MX-80 bentonite with different hexadecylpyridinium (HDPy+) loadings were studied using equilibrium solutions of different ionic strengths. In HDPy(+)-modified bentonite, iodide and pertechnetate ions exhibited increasing sorption (characterized by the distribution ratio, Rd), while Cs+ and Sr2+ showed decreasing sorption with increasing organophilicity. In case of medium-loading levels, the simultaneous sorption of anions (I- and TcO4-) and cations (Cs+ and Sr2+) was observed. Sorption of ions was influenced by the composition of the electrolytes employed. It decreased gradually with increasing ionic strength of the electrolyte solutions. The experiments revealed the general tendency that the diffusivity (Da [cm2.s-1]) for iodide and pertechnetate decreases with increasing organophilicity and increases with increasing ionic strength of the equilibrium solutions, confirming the results of the sorption experiments. Additionally, some mineralogical and chemical investigations, like IR spectral analysis of the organo-bentonite samples and exchange behavior of HDPy+, were performed. On the basis of these analyses, it was concluded that the alkylammonium ions are sorbed as (1) HDPy+ cations, (2) HDPyCl molecules and (3) micelles with decreasing binding intensities in this order.
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Base de dados:
MEDLINE
Assunto principal:
Estrôncio
/
Poluentes Radioativos da Água
/
Bentonita
/
Radioisótopos de Césio
/
Pertecnetato Tc 99m de Sódio
/
Iodetos
/
Fissão Nuclear
Idioma:
En
Ano de publicação:
2001
Tipo de documento:
Article