Characterization of manganese oxide amendments for in situ remediation of mercury-contaminated sediments.
Characterization of manganese oxide amendments for in situ remediation of mercury-contaminated sediments.
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用于汞污染沉积物原位修复的氧化锰改良剂的表征。
DOI：
10.1039/c7em00576h
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Peggy A. O'Day
中科院分区：
文献类型：
--
作者：
A. Leven;D. Vlassopoulos;M. Kanematsu;J. Goin;Peggy A. O'Day
研究了锰氧化物相软锰矿或硼镁矿对汞污染沉积物的修复作用。由于无机汞甲基化是细菌硫酸盐还原的副产物，氧化锰与孔隙水的反应应使沉积物氧化电位高于有利于汞甲基化的水平。在沉淀池中观实验中，研究了锰氧化物的矿物学和氧化态随时间的变化。在沉淀池中观实验中，锰氧化物改进剂要么混合到汞污染的沉积物中，要么作为沉积物顶部的薄层沙盖。在手术4至15个月期间取样中体，并用x射线吸收光谱（XAS）对固相进行表征。对于软锰矿修正的沉积物，Mn（iv）氧化物转变为Mn(iii)-氢氧化物和Mn， Fe(iii, ii)-氧化物相的混合物，随着时间的推移，随着中生态沉积物的减少，Mn(ii)-碳酸盐组分逐渐增加。对于硼镁矿修正后的沉积物，在4个月时发现了氧化锰（Mn）和碳酸锰（Mn），表明锰的还原速度比软锰矿快。经过15个月的反应，黑锰矿完全转化为碳酸锰，而在软锰矿介体中，除了碳酸锰外，还存在残余的Mn， Fe（iii, ii）氧化物相。反应10个月后，在薄层砂帽中，软锰矿和硼镁矿的XAS光谱均未发生变化。平衡相关系支持混合价（Mn, Fe）（iii, ii）氧化物相对矿物氧化还原缓冲的解释。结果表明，可以通过调整Mn（iv）氧化物的质量和类型、矿物结晶度、表面积和粒径来控制氧化还原缓冲剂的改良剂寿命。对于给定的场地，应评估修正封盖与与沉积物混合，以确定最佳的处理方法，这可能取决于应用限制，Mn（iv）氧化物转化速率以及重新应用的频率，以保持所需的氧化状态和pH值。
Addition of Mn(iv)-oxide phases pyrolusite or birnessite was investigated as a remedial amendment for Hg-contaminated sediments. Because inorganic Hg methylation is a byproduct of bacterial sulfate reduction, reaction of Mn(iv) oxide with pore water should poise sediment oxidation potential at a level higher than favorable for Hg methylation. Changes in Mn(iv)-oxide mineralogy and oxidation state over time were investigated in sediment tank mesocosm experiments in which Mn(iv)-oxide amendment was either mixed into Hg-contaminated sediment or applied as a thin-layer sand cap on top of sediment. Mesocosms were sampled between 4 and 15 months of operation and solid phases were characterized by X-ray absorption spectroscopy (XAS). For pyrolusite-amended sediments, Mn(iv) oxide was altered to a mixture of Mn(iii)-oxyhydroxide and Mn, Fe(iii, ii)-oxide phases, with a progressive increase in the Mn(ii)-carbonate fraction over time as mesocosm sediments became more reduced. For birnessite-amended sediments, both Mn(iii) oxyhydroxide and Mn(ii) carbonate were identified at 4 months, indicating a faster rate of Mn reduction compared to pyrolusite. After 15 months of reaction, birnessite was converted completely to Mn(ii) carbonate, whereas residual Mn, Fe(iii, ii)-oxide phases were still present in addition to Mn(ii) carbonate in the pyrolusite mesocosm. In the thin-layer sand cap mesocosms, no changes in either pyrolusite or birnessite XAS spectra were observed after 10 months of reaction. Equilibrium phase relationships support the interpretation of mineral redox buffering by mixed-valent (Mn, Fe)(iii, ii)-oxide phases. Results suggest that amendment longevity for redox buffering can be controlled by adjusting the mass and type of Mn(iv) oxide applied, mineral crystallinity, surface area, and particle size. For a given site, amendment capping versus mixing with sediment should be evaluated to determine the optimum treatment approach, which may vary depending on application constraints, rate of Mn(iv) oxide transformation, and frequency of reapplication to maintain desired oxidation state and pH.
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影响因子：
11.4
作者：
J. E. Villinski;Peggy A. O'Day;T. Corley;M. Conklin
通讯作者：
J. E. Villinski;Peggy A. O'Day;T. Corley;M. Conklin
基于矿物质的修正案。
DOI：
10.2113/gselements.6.6.375
发表时间：
2010-12
期刊：
Elements (Quebec, Quebec)
影响因子：
--
作者：
O'Day PA;Vlassopoulos D
通讯作者：
Vlassopoulos D
影响因子：
11.4
作者：
Kay, JT;Conklin, MH;O'Day, PA
通讯作者：
O'Day, PA
影响因子：
5
作者：
Hinkle, Margaret A. G.;Flynn, Elaine D.;Catalano, Jeffrey G.
通讯作者：
Catalano, Jeffrey G.