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首页> 外文期刊>Environmental Science & Technology >Spectroscope Investigation of Ni Speciation in Hardened Cement Paste
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Spectroscope Investigation of Ni Speciation in Hardened Cement Paste

机译：分光镜研究硬化水泥浆中镍的形态

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摘要

Cement-based materials play an important role in multi-barrier concepts developed worldwide for the safe disposal of hazardous and radioactive wastes.Cement is used to condition and stabilize the waste materials and to construct the engineered barrier systems (container,backfill,and liner materials) of repositories for radioactive waste.In this study,Ni uptake by hardened cement paste has been investigated with the aim of improving our understanding of the immobilization process of heavy metals in cement on the molecular level.X-ray absorption spectroscopy (XAS) coupled with diffuse reflectance spectroscopy (DRS) techniques were used to determine the local environment of Ni in cement systems.The Ni-doped samples were prepared at two different water/cement ratios (0.4,1.3) and different hydration times (1 hour to 1 year) using a sulfate-resisting Portland cement.The metal loadings and the metal salts added to the system were varied (50 up to 5000 mg/kg;NO_3~-,SO_4~(2-),Cl~-).The XAS study showed that for all investigated systems Ni(ll) is predominantly immobilized in a layered double hydroxide (LDH) phase,which was corroborated by DRS measurements.Only a minor extent of Ni(II) precipitates as Ni-hydroxides (alpha-Ni(OH)_2 and beta-Ni(OH)_2).This finding suggests that Ni-Al LDH,rather than Ni-hydroxides,is the solubility-limiting phase in the Ni-doped cement system.
机译：水泥基材料在全球范围内为安全处置危险和放射性废物而开发的多屏障概念中起着重要作用。水泥用于调节和稳定废物材料并构建工程屏障系统（容器，回填和衬里材料）本研究研究了硬化水泥浆对镍的吸收，目的是在分子水平上增进我们对水泥中重金属固定化过程的了解.X射线吸收光谱（XAS）耦合采用扩散反射光谱法（DRS）来确定水泥系统中镍的局部环境。以两种不同的水/水泥比（0.4,1.3）和不同的水化时间（1小时至1年）制备掺杂Ni的样品），使用抗硫酸盐波特兰水泥。系统中的金属负载量和添加的金属盐变化不一（50至5000 mg / kg; NO_3〜-，SO_4〜（2-），Cl〜-）。 dy显示，对于所有研究的系统，Ni（II）主要固定在层状双氢氧化物（LDH）相中，这通过DRS测量得到证实。只有少量Ni（II）以氢氧化物形式沉淀（α-Ni（ OH）_2和β-Ni（OH）_2）。这一发现表明，Ni-Al LDH而不是Ni-氢氧化物是在Ni掺杂水泥体系中的溶解度限制相。

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  • 来源
    《Environmental Science & Technology》 |2006年第7期|p.2275-2282|共8页
  • 作者

    M.VESPA; R.DAHN; D.GROLIMUND; E.WIELAND; A.M.SCHEIDEGGER;

  • 作者单位

    Paul Schener Institute,Laboratory for Waste Management,5232 Villigen PSI,Switzerland,and Department of Environmental Sciences,Swiss Federal Institute of Technology (ETH),Zurich,Switzerland;

    Paul Schener Institute,Laboratory for Waste Management,5232 Villigen PSI,Switzerland,and Department of Environmental Sciences,Swiss Federal Institute of Technology (ETH),Zurich,Switzerland;

    Paul Schener Institute,Laboratory for Waste Management,5232 Villigen PSI,Switzerland,and Department of Environmental Sciences,Swiss Federal Institute of Technology (ETH),Zurich,Switzerland;

    Paul Schener Institute,Laboratory for Waste Management,5232 Villigen PSI,Switzerland,and Department of Environmental Sciences,Swiss Federal Institute of Technology (ETH),Zurich,Switzerland;

    Paul Schener Institute,Laboratory for Waste Management,5232 Villigen PSI,Switzerland,and Department of Environmental Sciences,Swiss Federal Institute of Technology (ETH),Zurich,Switzerland;

  • 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;
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