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Diffusion of Na(I), Cs(I), Sr(II) and Eu(III) in smectite rich natural clay
- Source :
- Journal of Environmental Radioactivity. 151:218-223
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- Diffusion of Na(I), Cs(I), Sr(II) and Eu(III) in smectite rich natural clay, proposed as a backfill material in the Indian geological repository, was studied using the out-diffusion method. Radiotracers (22)Na, (137)Cs, (85)Sr and (154)Eu were used; the first three are carrier-free enabling experimental work at sub-micromolar metal ion concentration, and Eu(III) tracer (154)Eu was used at sub millimolar concentration. An out-diffusion methodology, wherein a thin planar source of radioactivity placed between two clay columns diffuses out, was used to obtain the apparent diffusion coefficient (Da) values. This methodology enabled determination of diffusion coefficient even for strongly sorbing (154)Eu. Da values for (22)Na, (137)Cs, (85)Sr and (154)Eu were 2.35 (±0.14) × 10(-11), 2.65 (±0.09) × 10(-12), 3.32 (±0.15) × 10(-11) and 1.23 (±0.15) × 10(-13) m(2) s(-1), respectively. Da values were found to be in fair agreement with literature data reported for similar mineralogical sediments. Sorption of radionuclides on the clay was also determined in the present study and differences in Da values were rationalized on the basis of sorption data. Distribution ratios (Kd) for Cs(I) and Eu(III) were higher than that for Sr(II), which in turn was higher than that for Na(I).
- Subjects :
- Molar concentration
010504 meteorology & atmospheric sciences
Health, Toxicology and Mutagenesis
Diffusion
Analytical chemistry
India
chemistry.chemical_element
010403 inorganic & nuclear chemistry
01 natural sciences
Metal
Europium
Radiation Monitoring
TRACER
Soil Pollutants, Radioactive
Environmental Chemistry
Waste Management and Disposal
0105 earth and related environmental sciences
Radioisotopes
Radionuclide
Sodium Radioisotopes
Silicates
Sorption
General Medicine
Pollution
0104 chemical sciences
chemistry
Cesium Radioisotopes
visual_art
Strontium Radioisotopes
visual_art.visual_art_medium
Clay
Aluminum Silicates
Clay minerals
Nuclear chemistry
Subjects
Details
- ISSN :
- 0265931X
- Volume :
- 151
- Database :
- OpenAIRE
- Journal :
- Journal of Environmental Radioactivity
- Accession number :
- edsair.doi.dedup.....f256f5d41cfa088d14ad6db86ab8877e