Sulfidation and Reoxidation of U(VI)-Incorporated Goethite: Implications for U Retention during Sub-Surface Redox Cycling.
Sulfidation and Reoxidation of U(VI)-Incorporated Goethite: Implications for U Retention during Sub-Surface Redox Cycling.
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DOI：
10.1021/acs.est.2c05314
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发表时间：
2022-12-20
影响因子：
11.4
通讯作者：
Shaw, Samuel
中科院分区：
文献类型：
--
作者：
Stagg, Olwen;Morris, Katherine;Townsend, Luke Thomas;Kvashnina, Kristina O.;Baker, Michael L.;Dempsey, Ryan L.;Abrahamsen-Mills, Liam;Shaw, Samuel
60多年的核活动造成了全球土地污染和放射性废物的遗留问题。铀（U）是这一遗产的重要组成部分，存在于放射性废物和许多受污染的场地中。含铀铁（氧氢）氧化物可能对环境中的铀迁移提供长期的屏障。然而，由于硫酸盐的微生物还原，铁（羟基）氧化物的还原溶解可在与含水硫化物（硫化）反应时发生，含水硫化物是一种常见的环境物种。在这项工作中，U（VI）-针铁矿最初与硫化物水溶液反应，然后再氧化反应，以进一步了解波动的环境条件下的U物种的长期命运。在硫化的第一天，观察到水U的瞬时释放，可能是由于中间体铀酰（VI）-过硫化物物种。尽管如此，总的U被保留在固相中，在硫化体系中形成纳米晶U（IV）O2，沿着持久的U（V）组分。在再氧化，U与铁（oxyhydr）氧化物相作为吸附的铀酰（约65%）或纳入U（35%）的物种。这些研究结果支持铁（oxyhydr）氧化物作为一个障碍，在环境中的U迁移的总体概念，即使在波动的氧化还原条件下。U（VI）−针铁矿与硫化物水溶液的反应会导致微量铀水溶液的短暂再活化，并使U（IV）O2长期固相保留。
Over 60 years of nuclear activity have resulted in a global legacy of contaminated land and radioactive waste. Uranium (U) is a significant component of this legacy and is present in radioactive wastes and at many contaminated sites. U-incorporated iron (oxyhydr)oxides may provide a long-term barrier to U migration in the environment. However, reductive dissolution of iron (oxyhydr)oxides can occur on reaction with aqueous sulfide (sulfidation), a common environmental species, due to the microbial reduction of sulfate. In this work, U(VI)–goethite was initially reacted with aqueous sulfide, followed by a reoxidation reaction, to further understand the long-term fate of U species under fluctuating environmental conditions. Over the first day of sulfidation, a transient release of aqueous U was observed, likely due to intermediate uranyl(VI)–persulfide species. Despite this, overall U was retained in the solid phase, with the formation of nanocrystalline U(IV)O2 in the sulfidized system along with a persistent U(V) component. On reoxidation, U was associated with an iron (oxyhydr)oxide phase either as an adsorbed uranyl (approximately 65%) or an incorporated U (35%) species. These findings support the overarching concept of iron (oxyhydr)oxides acting as a barrier to U migration in the environment, even under fluctuating redox conditions. Reaction of U(VI)−goethite with aqueous sulfide results in transient remobilization of trace levels of aqueous uranium with long-term solid phase retention of U(IV)O2.
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影响因子：
5
作者：
CANFIELD, DE
通讯作者：
CANFIELD, DE
影响因子：
4.6
作者：
EKSTROM, A
通讯作者：
EKSTROM, A
影响因子：
5
作者：
Doornbusch, Brodie;Bunney, Karl;Graefe, Markus
通讯作者：
Graefe, Markus
影响因子：
11.4
作者：
Boland, Daniel D.;Collins, Richard N.;Waite, T. David
通讯作者：
Waite, T. David
影响因子：
7.3
作者：
Kumar, Naresh;Pacheco, Juan Lezama;Brown, Gordon E., Jr.
通讯作者：
Brown, Gordon E., Jr.