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首页> 外文期刊>Environmental Science & Technology >Depassivation of Aged Fe~0 by Ferrous Ions: Implications to Contaminant Degradation
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Depassivation of Aged Fe~0 by Ferrous Ions: Implications to Contaminant Degradation

机译：亚铁离子对陈旧的Fe〜0的钝化作用：对污染物降解的影响

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Investigation of the effects of ferrous iron (Fe(Ⅱ)) on the ability of aged (iron oxide coated) Fe~0 to degrade trichloroethylene (TCE) has revealed that,while neither aged Fe° nor Fe(Ⅱ) separately were able to degrade TCE,approximately 95% of the TCE present was degraded after exposure to a mixture of aged Fe~0 and Fe(Ⅱ) for 21 days.The rates of TCE degradation increased with an increase in Fe(Ⅱ) concentration from 0 to 1.6 mM and then reached a relative plateau.Results of Fe(Ⅱ) "adsorption" studies revealed that the equilibrium pH decreased significantly with an increase in Fe(Ⅱ) concentration.Proton release during adsorption of Fe(Ⅱ) to iron oxide coatings was identified as being responsible for promotion of surface dissolution and,concomitantly,enhancement in extent of TCE reduction by aged Fe~0.Results of open circuit potential analysis and Tafel plot measurement showed that the corrosion potential of aged Fe~0 (E_(corr)) in the presence of Fe(Ⅱ) decreased to levels similar to that of Fe~0/Fe~(2+),while significant increase in corrosion current (I_(corr)) and decrease in polarization resistance (R_p) were found with an increase in Fe(Ⅱ) concentration.The fact that the effects of different Fe(Ⅱ) concentrations on the E_(corr),I_(corr),and Rp was decoupled from their effects on TCE degradation by aged Fe~0 suggested that the enhancement of TCE degradation in the presence of Fe(Ⅱ) was attributable to the dissolution of the Fe(Ⅲ) oxyhydroxide layer coating the aged Fe~0.While the presence of Fe(Ⅱ) may also lead to transformation of the Fe(Ⅲ) (oxy)hydroxide coating to more crystalline phases,the rate of reduction of compounds such as TCE by Fe(Ⅱ) associated with the Fe(Ⅲ) (oxy)hydroxide coating is substantially slower than that mediated by Fe~0.These findings provide new insight into the molecular-scale interaction of aged Fe~0 and ferrous iron with particular implications for sustaining the reactivity of Fe~0-mediated degradation of contaminants in iron-bearing environments.
机译：对亚铁离子（Fe（Ⅱ））对陈旧的（氧化铁包覆的）Fe〜0降解三氯乙烯（TCE）的能力的研究表明，尽管陈化的Fe°和Fe（Ⅱ）均不能降解TCE，暴露于老化的Fe〜0和Fe（Ⅱ）混合物21天后，约有95％的TCE降解。TCE降解速率随Fe（Ⅱ）浓度从0增加到1.6而增加Fe（Ⅱ）的“吸附”研究结果表明，平衡pH随Fe（Ⅱ）浓度的增加而显着降低。确定了Fe（Ⅱ）在氧化铁涂层上吸附过程中的质子释放。 Fe〜0促进了表面溶解，并相应地提高了TCE降低的程度。开路电势分析和Tafel图测量结果表明，Fe〜0的腐蚀电位为（E_（corr）） Fe（Ⅱ）存在下降至类似于tha的水平Fe〜0 / Fe〜（2+）的t随Fe（Ⅱ）浓度的增加而显着增加，腐蚀电流（I_（corr））和极化电阻（R_p）降低。 Fe〜0对不同浓度的Fe（Ⅱ）对E_（corr），I_（corr）和Rp的影响对TCE降解的影响是不相关的，表明在Fe（Ⅱ）存在下，TCE降解的增强为归因于老化的Fe〜0涂层上的Fe（Ⅲ）羟基氧化物层的溶解。虽然Fe（Ⅱ）的存在也可能导致Fe（Ⅲ）羟基氧化物涂层转变为更多的结晶相，速率Fe（Ⅱ）与氢氧化三价铁（羟基）涂层对三氯乙烯（TCE）等化合物的还原作用明显慢于Fe〜0介导的还原作用。这些发现为老化Fe〜的分子尺度相互作用提供了新的见识。 0和亚铁，对于维持含铁环境中Fe〜0介导的污染物降解的反应性特别重要讽刺。

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  • 来源
    《Environmental Science & Technology》 |2013年第23期|13712-13720|共9页
  • 作者

    Tongxu Liu; Xiaomin Li; T.David Waite;

  • 作者单位

    School of Civil and Environmental Engineering,University of New South Wales,Sydney,NSW,Australia 2052,Guangdong Institute of Eco-Environmental and Soil Sciences,Guangzhou,Guangdong,P.R.China 510650;

    School of Civil and Environmental Engineering,University of New South Wales,Sydney,NSW,Australia 2052;

    School of Civil and Environmental Engineering,University of New South Wales,Sydney,NSW,Australia 2052;

  • 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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  • 正文语种 eng
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