Immobilization of Hg(II) by coprecipitation in sulfate-cement systems.
Immobilization of Hg(II) by coprecipitation in sulfate-cement systems.
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DOI：
10.1021/es202939v
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发表时间：
2012-06-19
影响因子：
11.4
通讯作者：
O'Day, Peggy A.
中科院分区：
文献类型：
--
作者：
Serrano, Susana;Vlassopoulos, Dimitri;Bessinger, Brad;O'Day, Peggy A.
在硫酸盐水泥修复土壤和沉积物的共沉淀和吸附实验中，研究了铝或铁钙矾石型和高ph相形成过程中溶解汞的吸收和分子形态。XRD分析表明，钙矾石和少量石膏是Al体系的主要相，而石膏和水合铁是Hg-Fe析出相的主要产物。通过体汞EXAFS、电子探针和微聚焦xrf图谱表征Hg - al固体，发现Hg与Cl配体配位、多个Hg和Cl后向散射原子以及Hg作为小颗粒的浓度。热力学预测与体相的实验结果一致，但汞的形态表明与最终溶液缺乏平衡。结果表明，汞作为多核氯汞（II）盐在钙矾石中的物理包封是主要的固定机制。在Hg - Fe固体中，结构表征表明Hg仅由O原子配位和Fe后向散射原子配位，这与Hg(OH)20与水合铁共沉淀的球内配位一致。水合铁的沉淀将汞从溶液中除去，但生成的固体充分水化，使被吸收的汞与水溶液平衡。低汞浓度与水泥和FeSO4改性反应的吸附样品的电子探针XRF表征表明Hg和Fe的相关性，支持Fe（III）氧化物相沉淀去除Hg的解释。
Uptake and molecular speciation of dissolved Hg during formation of Al- or Fe-ettringite-type and high-pH phases were investigated in coprecipitation and sorption experiments of sulfate-cement treatments used for soil and sediment remediation. Ettringite and minor gypsum were identified by XRD as primary phases in Al systems, whereas gypsum and ferrihydrite were the main products in Hg–Fe precipitates. Characterization of Hg–Al solids by bulk Hg EXAFS, electron microprobe, and microfocused-XRF mapping indicated coordination of Hg by Cl ligands, multiple Hg and Cl backscattering atoms, and concentration of Hg as small particles. Thermodynamic predictions agreed with experimental observations for bulk phases, but Hg speciation indicated lack of equilibration with the final solution. Results suggest physical encapsulation of Hg as a polynuclear chloromercury(II) salt in ettringite as the primary immobilization mechanism. In Hg–Fe solids, structural characterization indicated Hg coordination by O atoms only and Fe backscattering atoms that is consistent with inner-sphere complexation of Hg(OH)20 coprecipitated with ferrihydrite. Precipitation of ferrihydrite removed Hg from solution, but the resulting solid was sufficiently hydrated to allow equilibration of sorbed Hg species with the aqueous solution. Electron microprobe XRF characterization of sorption samples with low Hg concentration reacted with cement and FeSO4 amendment indicated correlation of Hg and Fe, supporting the interpretation of Hg removal by precipitation of an Fe(III) oxide phase.
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影响因子：
11.4
作者：
MCWHINNEY, HG;COCKE, DL;ORTEGO, JD
通讯作者：
ORTEGO, JD
影响因子：
1.5
作者：
DRITS, VA;SAKHAROV, BA;MANCEAU, A
通讯作者：
MANCEAU, A
影响因子：
4.6
作者：
BARNUM, DW
通讯作者：
BARNUM, DW
影响因子：
6.1
作者：
Ariza, JLG;Giráldez, I;Morales, E
通讯作者：
Morales, E
DOI：
10.1051/jp4:1997249
发表时间：
1997-04-01
期刊：
JOURNAL DE PHYSIQUE IV
影响因子：
--
作者：
Bargar, JR;Persson, P;Brown, GE
通讯作者：
Brown, GE