Separate or Simultaneous Removal of Radioactive Cations and Anions from Water by Layered Sodium Vanadate-Based Sorbents

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• 作者：Sarina Sarina ; Arixin Bo ; Dejun Liu ; Hongwei Liu ; Dongjiang Yang ; Cuifeng Zhou ; Norbert Maes ; Sridhar Komarneni ; Huaiyong Zhu
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：August 26, 2014
• 年：2014
• 卷：26
• 期：16
• 页码：4788-4795
• 全文大小：623K
• ISSN：1520-5002

文摘

Nanofibers of sodium vanadate, consisting of very thin negatively charged layers and exchangeable sodium ions between the layers, are efficient sorbents for the removal of radioactive ¹³⁷Cs⁺ and ⁸⁵Sr²⁺ cations from water. The exchange of ¹³⁷Cs⁺ or ⁸⁵Sr²⁺ ions with the interlayer Na⁺ ions eventually triggered structural deformation of the thin layers, trapping the ¹³⁷Cs⁺ and ⁸⁵Sr²⁺ ions in the nanofibers. Furthermore, when the nanofibers were dispersed in a AgNO₃ solution at pH >7, well-dispersed Ag₂O nanocrystals formed by firmly anchoring themselves on the fiber surfaces along planes of crystallographic similarity with those of Ag₂O. These nanocrystals can efficiently capture I^{鈥?/sup> anions by forming a AgI precipitate, which was firmly attached to the substrates. We also designed sorbents that can remove 137Cs+ and 125I鈥?/sup> ions simultaneously for safe disposal by optimizing the Ag₂O loading and sodium content of the vanadate. This study confirms that sorbent features such as fibril morphology, negatively charged thin layers and readily exchangeable Na+ ions between the layers, and the crystal planes for the formation of a coherent interface with Ag₂O nanocrystals on the fiber surface are very important for the simultaneous uptake of cations and anions.}