Impacts of Repeated Redox Cycling on Technetium Mobility in the Environment.
Impacts of Repeated Redox Cycling on Technetium Mobility in the Environment.
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DOI：
10.1021/acs.est.7b02426
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发表时间：
2017-12
影响因子：
11.4
通讯作者：
N. Masters-Waage;K. Morris;J. Lloyd;S. Shaw;W. J.Frederick;Mosselmans;C. Boothman;P. Bots;Athanasios Rizoulis;F. Livens;G. Law
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文献类型：
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作者：
N. Masters-Waage;K. Morris;J. Lloyd;S. Shaw;W. J.Frederick;Mosselmans;C. Boothman;P. Bots;Athanasios Rizoulis;F. Livens;G. Law
锝是一个有问题的污染物在核网站和鲜为人知的是如何重复微生物介导的氧化还原循环影响其在环境中的命运。我们探讨这个问题的沉积物代表的塞拉菲尔德有限公司网站，英国，在多个还原和氧化周期跨越1.5年。我们发现，从沉积物到解决方案的再动员的Tc的量显着减少后，重复的氧化还原循环。X射线吸收光谱（XAS）证实，沉积物结合的Tc是目前作为含水TcO 2-样链在整个实验和Tc的增加电阻remobilization（通过再氧化为可溶性TcO 4-）导致从两个缩短TcO 2链在氧化还原循环和协会的Tc（IV）与铁相在沉积物中。我们还观察到，Tc（IV）在生物还原过程中留在溶液中可能与胶体磁铁矿纳米粒子。这些研究结果突出了Tc和Fe地球化学循环之间的重要联系，对Tc的长期环境流动性具有重要意义，特别是在短暂的氧化还原条件下。
Technetium is a problematic contaminant at nuclear sites and little is known about how repeated microbiologically mediated redox cycling impacts its fate in the environment. We explore this question in sediments representative of the Sellafield Ltd. site, UK, over multiple reduction and oxidation cycles spanning ∼1.5 years. We found the amount of Tc remobilised from the sediment into solution significantly decreased after repeated redox cycles. X-ray Absorption Spectroscopy (XAS) confirmed that sediment bound Tc was present as hydrous TcO2-like chains throughout experimentation and that Tc's increased resistance to remobilization (via reoxidation to soluble TcO4-) resulted from both shortening of TcO2 chains during redox cycling and association of Tc(IV) with Fe phases in the sediment. We also observed that Tc(IV) remaining in solution during bioreduction was likely associated with colloidal magnetite nanoparticles. These findings highlight crucial links between Tc and Fe biogeochemical cycles that have significant implications for Tc's long-term environmental mobility, especially under ephemeral redox conditions.