کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8084914 1521746 2016 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Diffusion behavior of selenite in purified bentonite
ترجمه فارسی عنوان
رفتار نفوذ سلنیت در بنتونیت خالص
کلمات کلیدی
بنتونیت خالص، نفوذ، سلنیت، قدرت یونیک، انرژی فعال سازی،
موضوعات مرتبط
مهندسی و علوم پایه مهندسی انرژی مهندسی انرژی و فناوری های برق
چکیده انگلیسی
Selenium (Se) is an important element for assessing the safety of high-level waste disposal. In this study, the diffusion coefficients of selenite in purified bentonite were investigated. A Japanese purified sodium bentonite, Kunipia-F, which contains approximately 99 wt% montmorillonite, was used in this experiment. Bentonite powder was compacted into cylinders (diameter, 10 mm; height, 10 mm; dry density, 0.8-1.6 Mg m−3). Each compacted bentonite specimen was inserted into an acrylic resin column and saturated with 0.01 M-1.0 M of NaCl (aq.) for 30 days. One side of the bentonite was spiked with 10 μL of tracer solution containing 0.13 M Na2SeO3 and it was kept at 10, 25, 40, or 55 °C for 1-29 days. The apparent diffusion coefficients of selenite in compacted bentonite were 2.5 × 10−11 to 1.9 × 10−13 m2 s−1 and decreased with the increase in dry density. The ionic strength showed no significant effect on the apparent diffusion coefficient of selenite for bentonite densities higher than 1.4 Mg m−3. However, the apparent diffusion coefficients for 1 M NaCl were several times larger than those in 0.1 or 0.01 M NaCl for densities lower than 1.2 Mg m−3. This increase in diffusion coefficient would be caused by a change in anion accessible porosity. The apparent diffusion coefficient would be explained by Archie's law and is proportional to exponentiation of porosity. It is desired to measure exact anion accessible porosity. The activation energy of selenite in purified bentonite was 20 ± 4 kJ mol−1 and was similar to the activation energies of oxo-anions in free water. This also indicates that selenite diffuses in free pore water in the bentonite.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Progress in Nuclear Energy - Volume 92, September 2016, Pages 279-285
نویسندگان
, , , , ,