...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Environmental Science & Technology >Evidence for the Interaction of Technetium Colloids with Humic Substances by X-ray Absorption Spectroscopy
【24h】

Evidence for the Interaction of Technetium Colloids with Humic Substances by X-ray Absorption Spectroscopy

机译：X射线吸收光谱法研究Tech胶体与腐殖质相互作用的证据

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Spectroscopic extended X-ray absorption fine structure (EXAFS) evidence was obtained on the chemical environment of 99{sup left}Tc(IV) atoms formed upon introduction of (TcO{sub}4){sup}- into four types of laboratory-scale synthetic and natural systems which mimic in situ natural reducing conditions in humic-rich geochemical environments: (a) magnetite/pyrite in synthetic groundwater in the absence of humic substances (HSs), (b) magnetite/pyrite in natural Gorleben groundwater in the presence of HSs, (c) Boom clay sediment mixed with synthetic groundwater, and (d) Gorleben sand mixed with natural Gorleben groundwater. The investigated systems obey to pH 8-9 conditions, and all measured samples show similar EXAFS spectra for Tc, which could be fitted by a hydrated TcO{sub}2·H{sub}2O phase. The results are interpreted as follows: upon introduction of high concentrations (millimolar to micromolar) of TcO{sub}4 to chemically reducing environments, small Tc(IV) oxidic polymers are formed, which either may aggregate into larger units (colloids) and finally precipitate or may interact in their polymeric form with (dissolved and immobile) humic substances. This latter type of interaction-Tc(IV) colloid sorption onto HSs-differs significantly from the generally accepted metal-humate complexation and therefore offers new views on the possible reaction pathways of metals and radionuclides in humic-rich environments.
机译：在将（TcO {sub} 4）{sup}-引入四种类型的实验室中后形成的99个{sup left} Tc（IV）原子的化学环境中，获得了扩展的X射线吸收光谱精细结构（EXAFS）证据。在富腐殖质地球化学环境中模拟原位自然还原条件的大规模合成和天然系统：（a）不含腐殖质（HSs）的合成地下水中的磁铁矿/黄铁矿，（b）戈尔本天然地下水中的磁铁矿/黄铁矿HS的存在；（c）动臂粘土沉积物与合成地下水混合，以及（d）Gorleben砂与天然Gorleben地下水混合。所研究的系统遵循pH 8-9的条件，所有测得的样品均显示出相似的Tc EXAFS光谱，可以通过水合TcO {sub} 2·H {sub} 2O相进行拟合。结果解释如下：将高浓度（毫摩尔至微摩尔）的TcO {sub} 4引入化学还原环境后，会形成小的Tc（IV）氧化性聚合物，它们可能会聚集成更大的单元（胶体），最后会与腐殖质（溶解的和不可移动的）沉淀或以聚合形式相互作用。后者的相互作用类型Tc（IV）胶体吸附到HSs上与公认的金属-腐殖酸盐络合物有很大不同，因此，在富含腐殖酸的环境中，金属和放射性核素可能的反应途径提供了新的观点。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号