Highly Efficient Iodine Capture by Layered Double Hydroxides Intercalated with Polysulfides

• DOI: 10.1021/cm5036997
• Publication Date: 2014-11-24T17:27:15Z
• Authors: Shulan Ma; Saiful M. Islam; Yurina Shim; Qingyang Gu; Pengli Wang; Hao Li; Genban Sun; Xiaojing Yang; Mercouri G. Kanat...
• Keywords: 01 natural sciences; 0104 chemical sciences

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 ...