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首页> 外文期刊>Environmental Science & Technology >Polymerization of Silicate on Hematite Surfaces and Its Influence on Arsenic Sorption
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Polymerization of Silicate on Hematite Surfaces and Its Influence on Arsenic Sorption

机译：硅酸盐在赤铁矿表面的聚合及其对砷吸附的影响

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Iron oxides and oxyhydroxides are important sorbents for arsenic in soils, sediments, and water treatment systems, but their long-term potential for arsenic retention may be diminished by the formation of polymeric silicate on their surfaces. To study these interactions, we first investigated the sorption of silicate to colloidal hematite (α-Fe_2O_3) in short-term (48 h) and long-term (210 days) batch experiments. The polymerization of silicate on the hematite surface was monitored by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The pH dependence of silicate sorption exhibited a maximum between pH 9.0 and 9.5. The condensation of silicate on hematite surfaces adsorbed from monomeric silicate solutions steadily continued over the 210 day period, whereby surface polymerization was slower at pH 3 than at pH 6. The effect of silicate surface polymerization on arsenate and arsenite sorption was studied by use of hematite pre-equilibrated with silicate for different time periods of up to 210 days. The competitive effect of silicate on arsenate and arsenite sorption increased with increasing silicate pre-equilibration time. Only under strongly acidic conditions (pH 3), where silicate sorption was weakest and surface polymerization was slowest, was arsenate and arsenite sorption not affected by the presence of silicate. We conclude that the long-term exposure to dissolved silicate can decrease the potential of natural iron (oxyhydr)oxides for adsorbing inorganic arsenic
机译：氧化铁和羟基氧化铁是土壤，沉积物和水处理系统中砷的重要吸附剂，但是由于其表面上形成聚合硅酸盐，其长期保留砷的潜力可能会降低。为了研究这些相互作用，我们首先在短期（48小时）和长期（210天）批量实验中研究了硅酸盐对胶体赤铁矿（α-Fe_2O_3）的吸附。通过衰减全反射傅里叶变换红外光谱（ATR-FTIR）光谱监测赤铁矿表面硅酸盐的聚合。硅酸盐吸附的pH依赖性在pH 9.0和9.5之间显示最大值。从单体硅酸盐溶液吸附的硅酸盐在赤铁矿表面上的凝结持续持续了210天，因此在pH 3时表面聚合反应比在pH 6时慢。通过使用赤铁矿研究了硅酸盐表面聚合对砷酸盐和砷酸盐吸附的影响。在长达210天的不同时间内使用硅酸盐进行预平衡。硅酸盐对砷酸盐和亚砷酸盐吸附的竞争作用随着硅酸盐预平衡时间的增加而增加。仅在强酸性条件下（pH 3），硅酸盐的吸附最弱且表面聚合最慢，砷酸盐和砷酸盐的吸附不受硅酸盐的存在影响。我们得出的结论是，长期暴露于溶解的硅酸盐会降低天然铁（羟基氧化物）吸附无机砷的潜力

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  • 来源
    《Environmental Science & Technology》 |2012年第24期|13235-13243|共9页
  • 作者

    Iso ChristI; Yves Brechbuehl; Moritz Graf; Ruben Kretzschmar;

  • 作者单位

    Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, CHN, 8092 Zurich, Switzerland;

    Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, CHN, 8092 Zurich, Switzerland;

    Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, CHN, 8092 Zurich, Switzerland;

    Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, CHN, 8092 Zurich, Switzerland;

  • 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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