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首页> 外文期刊>Environmental Science & Technology >Reduction of Pertechnetate in Solution by Heterogeneous Electron Transfer from Fe(Ⅱ)-Containing Geological Material
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Reduction of Pertechnetate in Solution by Heterogeneous Electron Transfer from Fe(Ⅱ)-Containing Geological Material

机译：含Fe（Ⅱ）的地质材料中非均相电子转移还原高tech酸酯

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摘要

We have studied the surface-mediated reduction of pertechnetate (TcO_4~-) in solution by Fe(Ⅱ)-bearing fracture filling material from a natural fracture in granite, hornblende, and magnetite. The disappearance of technetium from solution was found to follow pseudo first order kinetics, the rate constant being dependent on the specific surface area and Fe-(Ⅱ) content of the solid. Comparison of the rate constants obtained in the experiments with fracture filling material containing chlorite as Fe(Ⅱ)-bearing mineral, hornblende, and magnetite indicates a strong influence of the binding manner of Fe(Ⅱ) in the solid phase. Magnetite, with a low band gap (0.1 eV) between the valence and conduction bands was found to be the most efficient reductant, and based on the ionic strength and pH dependence of the rate of TcO_4~-reduction, it is concluded that sorption of TcO_4~- on the magnetite surface by a ligand-exchange mechanism is the rate-determining reaction step: > SOH + TcO_4~- ←→ > SOTcO_3 + OH~-. Oxidative desorption of sorbed/precipitated TcO_2(s) into air-saturated ground-water was found to be very slow, most probably due to competing reactions between oxygen and the surface of the Fe(Ⅱ)-bearing solid.
机译：我们研究了花岗岩，角闪石和磁铁矿中天然裂缝中含Fe（Ⅱ）的裂缝填充材料对溶液中高tech酸盐（TcO_4〜-）的表面介导还原作用。发现solution从溶液中的消失遵循拟一级动力学，速率常数取决于固体的比表面积和Fe-（Ⅱ）含量。用含亚氯酸盐作为含Fe（Ⅱ）的矿物，角闪石和磁铁矿的裂缝填充材料进行的实验中获得的速率常数的比较表明，Fe（Ⅱ）在固相中的结合方式有很大的影响。发现在价带和导带之间具有低带隙（0.1 eV）的磁铁矿是最有效的还原剂，并且基于离子强度和pH对TcO_4〜还原速率的依赖性，得出结论：通过配体交换机制在磁铁矿表面上的TcO_4〜-是决定速率的反应步骤：> SOH + TcO_4〜-←→> SOTcO_3 + OH〜-。发现吸附/沉淀的TcO_2在空气饱和的地下水中的氧化解吸非常缓慢，这很可能是由于氧气与含Fe（Ⅱ）的固体表面之间的竞争反应所致。

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  • 来源
    《Environmental Science & Technology》 |1996年第7期|p.2263-2269|共7页
  • 作者

    DAQING CUI; TRYGVE E. ERIKSEN;

  • 作者单位

    Department of Chemistry, Nuclear Chemistry, Royal Institute of Technology, 100 44 Stockholm, Sweden;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境化学;
  • 关键词

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