Highly efficient iodine capture by layered double hydroxides intercalated with polysulfides

Shulan Ma, Saiful M. Islam, Yurina Shim, Qingyang Gu, Pengli Wang, Hao Li, Genban Sun, Xiaojing Yang, Mercouri G. Kanatzidis

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Abstract

We demonstrate strong iodine (I2) vapor adsorption using Mg/Al layered double hydroxide (MgAl-LDH) nanocomposites intercalated with polysulfide (Sx2-) groups (Sx-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- anions by the intercalated [Sx]2- 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 1.32, 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- ions that intercalated into the LDH gallery have high thermal stability (¥350 °C). The excellent iodine adsorption performance combined with the facile preparation points to the Sx-LDH systems as potential superior materials for adsorption of radioactive iodine, a waste product of the nuclear power industry.

Original languageEnglish
Pages (from-to)7114-7123
Number of pages10
JournalChemistry of Materials
Volume26
Issue number24
DOIs
Publication statusPublished - Dec 23 2014

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ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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