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首页> 外文期刊>Environmental Science & Technology >Mechanism of Selenite Removal by a Mixed Adsorbent Based on Fe-Mn Hydrous Oxides Studied Using X-ray Absorption Spectroscopy
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Mechanism of Selenite Removal by a Mixed Adsorbent Based on Fe-Mn Hydrous Oxides Studied Using X-ray Absorption Spectroscopy

机译：X射线吸收光谱研究基于Fe-Mn水合氧化物的混合吸附剂脱硒机理

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摘要

Selenium cycling in the environment is greatly controlled by various minerals, including Mn and Fe hydrous oxides. At the same time, such hydrous oxides are the main inorganic ion exchangers suitable (on the basis of their chemical nature) to sorb (toxic) anions, separating them from water solutions. The mechanism of selenite adsorption by the new mixed adsorbent composed of a few (amorphous and crystalline) phases [maghemite, MnCO_3, and X-ray amorphous Fe(Ⅲ) and Mn(Ⅲ) hydrous oxides] was studied by extended X-ray absorption fine structure (EXAFS) spectroscopy [supported by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) data]. The complexity of the porous adsorbent, especially the presence of the amorphous phases of Fe(Ⅲ) and Mn(Ⅲ) hydrous oxides, is the main reason for its high selenite removal performance demonstrated by batch and column adsorption studies shown in the previous work. Selenite was bound to the material via inner-sphere complexation (via oxygen) to the adsorption sites of the amorphous Fe(Ⅲ) and Mn(Ⅲ) oxides. This anion was attracted via bidentate binuclear comer-sharing coordination between SeO_3~(2-) trigonal pyramids and both FeO_6 and MnO_6 octahedra; however, the adsorption sites of Fe(Ⅲ) hydrous oxides played a leading role in selenite removal. The contribution of the adsorption sites of Mn(Ⅲ) oxide increased as the pH decreased from 8 to 6. Because most minerals have a complex structure (they are seldom based on individual substances) of various crystallinity, this work is equally relevant to environmental science and environmental technology because it shows how various solid phases control cycling of chemical elements in the environment.
机译：硒在环境中的循环受多种矿物的控制，包括锰和铁的水合氧化物。同时，这种水合氧化物是主要的无机离子交换剂（根据其化学性质），适合于吸附（有毒）阴离子，并将其与水溶液分离。通过扩展X射线吸收研究了由几种（非晶态和结晶态）相组成的新型混合吸附剂[磁铁矿，MnCO_3和X射线非晶态Fe（Ⅲ）和Mn（Ⅲ）水合氧化物]对亚硒酸盐的吸附机理。精细结构（EXAFS）光谱[由傅里叶变换红外（FTIR）和X射线衍射（XRD）数据支持]。多孔吸附剂的复杂性，尤其是Fe（Ⅲ）和Mn（Ⅲ）含水氧化物的非晶相的存在，是先前工作中分批和柱吸附研究证明其高亚硒酸盐去除性能的主要原因。亚硒酸盐通过内球络合（通过氧）与无定形Fe（Ⅲ）和Mn（Ⅲ）氧化物的吸附位点结合到材料上。该阴离子通过SeO_3〜（2-）三角锥与FeO_6和MnO_6八面体之间的双齿双核角共享配位吸引。然而，Fe（Ⅲ）水合氧化物的吸附位点在亚硒酸盐的去除中起主要作用。 pH值从8降低到6时，Mn（Ⅲ）氧化物的吸附位点增加。由于大多数矿物具有各种结晶度的复杂结构（很少基于单个物质），因此这项工作与环境科学同样重要。和环境技术，因为它显示了各种固相如何控制环境中化学元素的循环。

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  • 来源
    《Environmental Science & Technology》 |2014年第22期|13376-13383|共8页
  • 作者

    Natalia Chubar; Vasyl Gerda; Malgorzata Szlachta;

  • 作者单位

    School of Engineering and Built Environment, Glasgow Caledonian University, Cowcaddens Road 70, Glasgow G40BA, United Kingdom,Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Budapestlaan 4, 3584CD Utrecht, Netherlands;

    Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Budapestlaan 4, 3584CD Utrecht, Netherlands,Faculty of Chemistry, Kyiv Taras Shevchenko National University, Volodymyrska Street 60, 01601 Kyiv, Ukraine;

    Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Budapestlaan 4, 3584CD Utrecht, Netherlands,Faculty of Environmental Engineering, Wroclaw University of Technology, Wybrzeze Stanislawa Wyspianskiego 27, 50-370 Wroclaw, Poland;

  • 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);
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