Highly Efficient Iodine Capture by Layered Double Hydroxides Intercalated with Polysulfides

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• 作者：Shulan Ma ; Saiful M. Islam ; Yurina Shim ; Qingyang Gu ; Pengli Wang ; Hao Li ; Genban Sun ; Xiaojing Yang ; Mercouri G. Kanatzidis
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：December 23, 2014
• 年：2014
• 卷：26
• 期：24
• 页码：7114-7123
• 全文大小：771K
• ISSN：1520-5002

文摘

We demonstrate strong iodine (I₂) vapor adsorption using Mg/Al layered double hydroxide (MgAl-LDH) nanocomposites intercalated with polysulfide (S_x^{2鈥?/sup>) groups (S_x-LDH, x = 2, 4, 6). The as-prepared LDH/polysulfide hybrid materials display highly efficient iodine capture resulting from the reducing property of the intercalated polysulfides. During adsorption, the I₂ molecules are reduced to I₃鈥?/sup> anions by the intercalated [S_x]2鈥?/sup> groups that simultaneously are oxidized to form S₈. In addition to the chemical adsorption, additional molecular I₂ is physically captured by the LDH composites. As a result of these parallel processes, and despite their very low BET surface areas, the iodine capture capacities of S₂-LDH, S₄-LDH, and S₆-LDH are 鈭?.32, 1.52, and 1.43 g/g, respectively, with a maximum adsorption of 152% (wt %). Thermogravimetric and differential thermal analysis (TG-DTA), energy dispersive X-ray spectroscopy (EDS), and temperature-variable powder X-ray diffraction (XRD) measurements show the resulting I₃鈥?/sup> ions that intercalated into the LDH gallery have high thermal stability (鈮?50 掳C). The excellent iodine adsorption performance combined with the facile preparation points to the S_x-LDH systems as potential superior materials for adsorption of radioactive iodine, a waste product of the nuclear power industry.}