The thermal properties of SO4 2--intercalated Mg-Al layered double hydroxide (SO4.Mg-Al LDH) were investigated using simultaneous thermogravimetry-mass spectrometry (TG-MS), and the elimination behavior of sulfur oxides from this double hydroxide was examined. The TG-MS results showed that SO4.Mg-Al LDH decomposed in five stages. The first stage involved evaporation of surface-Adsorbed water and interlayer water in SO4.Mg-Al LDH. In the second, third, and fourth stages, dehydroxylation of the brucite-like octahedral layers in SO4.Mg-Al LDH occurred. The fifth stage corresponded to the elimination of SO4 2- intercalated in the interlayer of Mg-Al LDH, producing SO 2 and SO3. The thermal decomposition of SO 4.Mg-Al LDH resulted in the formation of SO2 and SO 3 at 900-1000 °C, which then reacted with H2O to form H2SO3 and H2SO4. The elimination of sulfur oxides increased with the decomposition time and temperature. Almost all of the intercalated SO4 2- was desulfurized from SO 4.Mg-Al LDH at 1000 °C; however, Mg-Al oxide was not formed due to the production of MgO and MgAl2O4.
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