Influence of inherent iron and oxygen concentrations on selenite sorption process using bentonite
Influence of inherent iron and oxygen concentrations on selenite sorption process using bentonite
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固有铁和氧浓度对膨润土吸附亚硒酸盐过程的影响
DOI：
10.1007/s11426-017-9091-4
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
刘春立
中科院分区：
文献类型：
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作者：
何建刚;乔雪玲;时燕琳;李遥;杨小雨;周万强;刘春立
膨润土中氧浓度和固有铁对Se（IV）吸附过程有显著影响。本研究采用间歇式实验方法研究了天然膨润土对亚硒酸盐的吸附，得到了在pH为2.0 ~ 10.0、缺氧条件下的分布系数（Kd）值。在有氧条件下pH = 4，在无氧条件下pH = 8时，kd值总是达到最大值；同时，缺氧条件下的kdvalue大于缺氧条件下的kdvalue，尤其是最大值。氧条件对氧化还原敏感Fe2+/Fe3+的比值有显著影响，这与氧/缺氧条件下kd值的差异密切相关。在缺氧和缺氧条件下，亚硒酸铁和绿锈可能是最大的钾值。在浸出实验中，我们发现膨润土中的Fe2+可以取代八面体薄片中的Mg2+和Al3+。采用傅立叶变换红外光谱（FTIR）、x射线衍射（XRD）和x射线吸收光谱（XAS）等光谱方法对反应后样品的表面性质进行表征。综上所述，本研究表明，在缺氧条件下，在充填/缓冲材料中添加含Fe2+的材料可以增强对79se （IV）的吸附。
The oxygen concentration and inherent Fe in bentonite have a significant influence on the Se(IV) sorption process. In this study, the sorption of selenite on natural bentonite was investigated using a batch experiment method, and the distribution coefficient (Kd) values were obtained in the pH range from 2.0 to 10.0 under oxic/anoxic conditions. TheKdvalues always reached a maximum value at a pH of 4 under oxic conditions and at a pH of 8 under anoxic conditions; meanwhile, theKdvalue under anoxic conditions was larger than the value under oxic conditions, especially in regard to the maximumKdvalues. The oxygen conditions have a significant influence on the ratio of redox-sensitive Fe2+/Fe3+, which was closely related to the difference in theKdvalues under both oxic/anoxic conditions. Ferric selenite and green rust could be responsible for the maximumKdvalues under oxic/anoxic conditions. In the leaching experiments, we found that the Fe2+in bentonite could replace Mg2+and Al3+in the octahedral sheet. Spectroscopy methods, such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) were used to characterize the surface properties of the samples after reaction. Overall, this study shows that the addition of Fe2+-containing materials into backfill/buffer materials under anoxic condition could enhance the sorption of79Se(IV).