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首页> 外文期刊>Environmental Science & Technology >Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide. 2. Results from X-ray Absorption Spectroscopy and X-ray Diffraction
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Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide. 2. Results from X-ray Absorption Spectroscopy and X-ray Diffraction

机译:结晶度较弱的锰氧化物氧化亚砷酸盐。 2. X射线吸收光谱和X射线衍射的结果

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摘要

Arsenite (As~(III)) oxidation by manganese oxides (Mn-oxides) serves to detoxify and, under many conditions, immobilize arsenic (As) by forming arsenate (As~V). As~(III) oxidation by Mn~(IV)-oxides can be quite complex, involving many simultaneous forward reactions and subsequent back reactions. During As~(III) oxidation by Mn-oxides, a reduction in oxidation rate is often observed, which is attributed to Mn-oxide surface passivation. X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD j data show that Mn~(II) sorption on a poorly crystalline hexagonal birnessite (δ-MnO_2) is important in passivation early during reaction with As~(III). Also, it appears that Mn~(III) in the δ-MnO_2 structure is formed by conproporfonauon of sorbed Mn~(II) and Mn~(IV) in the mineral structure. The content of Mn~(III) within the δ-MnO_2 structure appears to increase as the reaction proceeds. Binding of As~V to (VMnO_2 also changes as Mn~(III) becomes more prominent in the δ-MnO_2 structure. The data presented indicate that As~(III) oxidation and As~V sorption by poorly crystalline δ-MnO_2 is greatly affected by Mn oxidation state in the δ-MnO_2 structure.
机译:锰氧化物(Mn-氧化物)氧化砷(As〜(III))可解毒,并在许多条件下通过形成砷酸盐(As〜V)来固定砷(As)。 Mn(IV)-氧化物氧化As(III)非常复杂,涉及许多同时的正向反应和随后的反向反应。在Mn-氧化物氧化As〜(III)期间,经常观察到氧化速率降低,这归因于Mn-氧化物表面钝化。 X射线吸收光谱(XAS)和X射线衍射(XRD j数据表明,在与As〜(III)反应的早期,钝化早期的钝化六方晶水钠锰矿(δ-MnO_2)上的Mn〜(II)吸附是重要的。另外,似乎δ-MnO_2结构中的Mn〜(III)是由矿物结构中吸附的Mn〜(II)和Mn〜(IV)的共形成的,δ-MnO_2含量在δ-中。 MnO_2结构随着反应的进行而增加;随着δ〜MnO_2结构中Mn〜(III)的含量增加,As〜V与(VMnO_2的结合力也发生变化。 δ-MnO_2结构中Mn的氧化态极大地影响了结晶度差的δ-MnO_2对V的吸附。

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  • 来源
    《Environmental Science & Technology》 |2010年第22期|p.8467-8472|共6页
  • 作者单位

    Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, 152 Townsend Hall, Newark, Delaware 19716, United States;

    Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, 152 Townsend Hall, Newark, Delaware 19716, United States,Calera Corporation, 14600 Winchester Blvd.,Los Gatos, CA 95030;

    Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, 152 Townsend Hall, Newark, Delaware 19716, United States;

    Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, 152 Townsend Hall, Newark, Delaware 19716, United States,Departments of Earth and Planetary Sciences and Biology, The Johns Hopkins University, Baltimore, MD 21218;

    Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, 152 Townsend Hall, Newark, Delaware 19716, United States;

  • 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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