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首页> 外文期刊>Environmental Science & Technology >Sulfate Availability Drives Divergent Evolution of Arsenic Speciation during Microbially Mediated Reductive Transformation of Schwertmannite
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Sulfate Availability Drives Divergent Evolution of Arsenic Speciation during Microbially Mediated Reductive Transformation of Schwertmannite

机译：在微生物介导的Schwertmannite还原转化过程中，硫酸盐的可用性驱动砷形态的不同演化。

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摘要

The effect of SO_4~(2-) availability on the microbially mediated reductive transformation of As(V)-coprecipitated schwertmannite (Fe_8O_8(OH)_(3.2)(SO_4)_(2.4)(AsO_4)_(0.004)) was examined in long-term (up to 400 days) incubation experiments. Iron EXAFS spectroscopy showed siderite (FeCO_3) and mackinawite (FeS) were the dominant secondary Fe(Ⅱ) minerals produced via reductive schwertmannite transformation. In addition, ～25％ to ～65％ of the initial schwertmannite was also transformed relatively rapidly to goethite (αFeOOH), with the extent of this transformation being dependent on SO_4~(2-) concentrations. More specifically, the presence of high SO_4~(2-) concentrations acted to stabilize schwertmannite, retarding its transformation to goethite and allowing its partial persistence over the 400 day experiment duration. Elevated SO_4~(2-) also decreased the extent of dissimilatory reduction of Fe(Ⅲ) and As(Ⅴ), instead favoring dissimilatory SO_4~(2-) reduction. In contrast, whereSO_4~(2-) was less available, there was near-complete reduction of schwertmannite-and goethite-derived Fe(Ⅲ) as well as solid-phase As(Ⅴ). As a result, under low SO_4~(2-) conditions, almost no Fe(Ⅲ) or As(Ⅴ) remained toward the end of the experiment and arsenic solid-phase partitioning was controlled mainly by sorptive interactions between As(Ⅲ) and mackinawite. These As (Ⅲ)-mackinawite interactions led to the formation of an orpiment (As_2S_3)-like species. Interestingly, this orpiment-like arsenic species did not form under SO_4~(2-)-rich conditions, despite the prevalence of dissimilatory SO_4~(2-) reduction. The absence of an arsenic sulfide species under SO_4~(2-)-rich conditions appears to have been a consequence of schwertmannite persistence, combined with the preferential retention of arsenic oxyanions by schwertmannite. The results highlight the critical role that SO_4~(2-) availability can play in controlling solid-phase arsenic speciation, particularly arsenic-sulfur interactions, under reducing conditions in soils, sediments, and shallow groundwater systems.
机译：考察了SO_4〜（2-）可用性对As（V）共沉淀的Schwertmannite（Fe_8O_8（OH）_（3.2）（SO_4）_（2.4）（AsO_4）_（0.004））的微生物介导的还原转化的影响在长期（最多400天）的孵育实验中。铁的EXAFS光谱显示菱铁矿（FeCO_3）和麦基钠铁矿（FeS）是通过还原型Schwertmannite转变产生的主要次生Fe（Ⅱ）矿物。另外，初始Schwertmannite的〜25％～～ 65％也相对快速地转变为针铁矿（αFeOOH），这种转变的程度取决于SO_4〜（2-）的浓度。更具体地说，高SO_4〜（2-）浓度的存在起到稳定schwertmannite的作用，阻碍了其转变为针铁矿，并允许其在400天的实验过程中部分持久。 SO_4〜（2-）的升高也降低了Fe（Ⅲ）和As（Ⅴ）异化还原的程度，反而有利于SO_4〜（2-）异化还原。相反，在SO_4〜（2-）较少的情况下，Schwertmannite和针铁矿衍生的Fe（Ⅲ）和固相As（Ⅴ）几乎完全还原。结果，在低SO_4〜（2-）条件下，几乎没有Fe（Ⅲ）或As（Ⅴ）残留到实验结束，砷固相分配主要受As（Ⅲ）和As（Ⅲ）之间的吸附作用控制。麦金石。这些砷（Ⅲ）-马金榴石的相互作用导致形成了雌蕊（As_2S_3）样物种。有趣的是，尽管普遍存在异化的SO_4〜（2-）还原，但在富含SO_4〜（2-）的条件下仍未形成这种类似果皮的砷。在富含SO_4〜（2-）的条件下不存在硫化砷物质似乎是schwertmannite持久性的结果，而schwertmannite优先保留了砷含氧阴离子。结果表明，在土壤，沉积物和浅层地下水系统减少的条件下，SO_4〜（2-）的有效性可在控制固相砷形态（尤其是砷硫相互作用）中发挥关键作用。

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  • 来源
    《Environmental Science & Technology》 |2013年第5期|2221-2229|共9页
  • 作者

    Edward D. Burton; Scott G. Johnston; Peter Kraal; Richard T. Bush; Salirian Claff;

  • 作者单位

    Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480, Australia;

    Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480, Australia;

    Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480, Australia;

    Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480, Australia;

    Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480, Australia,Crop, Environment and Livestock Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan;

  • 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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