کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4547455 1627121 2007 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
U(VI) adsorption on aquifer sediments at the Hanford Site
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
U(VI) adsorption on aquifer sediments at the Hanford Site
چکیده انگلیسی
Aquifer sediments collected via split-spoon sampling in two new groundwater wells in the 200-UP-1 operable unit at the Hanford Site were characterized and showed typical Ringold Unit E Formation properties dominated by gravel and sand. High iron-oxide content in Fe oxide/clay coatings caused the highest U(VI) adsorption as quantified by batch Kd values, indicating iron oxides are the key solid adsorbent in the 200-UP-1 sediments that affect U(VI) fate and mobility. Even though U(VI) adsorption on the gravel-sized fraction of the sediments is considered to be negligible, careful characterization should be conducted to determine U(VI) adsorption on gravel, because of presence of Fe oxides coatings and diffusion-controlled adsorption into the gravel particles' interior surfaces. A linear adsorption isotherm was observed up to 10− 6 M (238 μg/L) of total U(VI) concentration in batch U(VI) adsorption tests with varying total U(VI) concentrations in spiked groundwater. U(VI) adsorption decreased with increasing concentrations of dissolved carbonate, because strong anionic aqueous uranium-carbonate complexes formed at high pH and high alkalinity conditions. Noticeable uranium desorption hysteresis was observed in a flow-through column experiment, suggesting that desorption Kd values for aged uranium-contaminated sediments at the Hanford Site can be larger than adsorption Kd values determined in short-term laboratory experiments and slow uranium release from contaminated sediments into the groundwater is expected.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Contaminant Hydrology - Volume 93, Issues 1–4, 15 August 2007, Pages 255-269
نویسندگان
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