Abstract
Kinetics on the dehydration reaction of interlayer water during the thermal treatment of synthetic LDHs was studied. LDHs with different layer charges such as Mg8Al2-CO3-LDH, Mg6Al2-CO3-LDH and Mg4Al2-CO3-LDH were used. The powder X-ray diffraction patterns and TGA diagrams of synthetic LDHs show the typical structural and thermal properties of MgAl-LDHs intercalated with carbonate. The non-isothermal kinetics for the loss of interlayer water molecules was investigated by the TGA diagrams. The water molecules dehydrated from interlayer of LDHs with similar activation energies of 106, 105 and 107 kJ mol-1 for the Mg8Al2-CO3-LDH, Mg6Al2-CO3-LDH and Mg4Al2-CO3-LDH at each inflection point of TGA curves, respectively. The dehydration reactions were controlled by the diffusion of water molecules through two-dimensional interlayers, and the frequency factors were 5.78x1011, 5.68x1010 and 4.66x1010 min-1 for the Mg8Al2-CO3-LDH, Mg6Al2-CO3-LDH and Mg4Al2-CO3-LDH, respectively.
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Rhee, S.W., Kang, M.J. Kinetics on dehydration reaction during thermal treatment of mgal-co3-ldhs. Korean J. Chem. Eng. 19, 653–657 (2002). https://doi.org/10.1007/BF02699312
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DOI: https://doi.org/10.1007/BF02699312