Uranium and Cesium sorption to bentonite colloids under carbonate-rich environments: Implications for radionuclide transport

Emily L. Tran, Nadya Teutsch, Ofra Klein-BenDavid, Noam Weisbrod

نتاج البحث: نشر في مجلةمقالةمراجعة النظراء

ملخص

In the context of geological disposal of radioactive waste, one of the controlling mechanisms for radionuclide migration through subsurface strata is sorption to mobile colloidal bentonite particles. Such particles may erode from the repository backfill or bentonite buffer and yield measurable (0.01–0.1 g/L) concentrations in natural groundwater. The extent of sorption is influenced by colloid concentration, ionic strength, radionuclide concentration, and the presence of competing metals. Uranium (VI) and cesium sorption to bentonite colloids was investigated both separately and together in low ionic strength (2.20 mM) artificial rainwater (ARW) and high ionic strength (169 mM) artificial groundwater (AGW; representative of a fractured carbonate rock aquitard). Sorption experiments were conducted as a factor of colloid concentration, initial metal concentration and opposing metal presence. It was shown that both U(VI) and Cs sorption were significantly reduced in AGW in comparison to ARW. Additionally, the sorption coefficient Kd of both metals was found to decrease with increasing colloid concentration. Competitive sorption experiments indicated that at high colloid concentration (1–2 g/L), Cs sorption was reduced in the presence of U(VI), and at low colloid concentration (0.01–0.5 g/L), both Cs and U(VI) Kds were reduced when they were present together due to competition for similar sorption sites. The results from this study imply that in brackish carbonate rock aquifers, typical of the Israeli northern Negev Desert, both U(VI) and Cs are more likely to be mobile as dissolved species rather than as colloid-associated solids.

اللغة الأصليةإنجليزيّة أمريكيّة
الصفحات (من إلى)260-269
عدد الصفحات10
دوريةScience of the Total Environment
مستوى الصوت643
المعرِّفات الرقمية للأشياء
حالة النشرنُشِر - 1 ديسمبر 2018

All Science Journal Classification (ASJC) codes

  • !!Environmental Engineering
  • !!Environmental Chemistry
  • !!Waste Management and Disposal
  • !!Pollution

بصمة

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