Thermal decomposition of layered double hydroxides: Kinetic modeling and validation

• Thermal decomposition of LDH modeled with non-isothermal kinetic analysis.
• Kinetic triplet for each stage reported.
• LDH with higher layer charge shows higher activation energy for every stage.
• Proposed model has been validated with isothermal experiment.
• It can be used in forecasting the behavior of thermal LDH decomposition.

Solid state kinetic process during the multistage thermal decomposition of Layered Double Hydroxide (LDH) reaction has been modeled utilizing model-free and model-based multivariate non-liner regression analysis. The physically most meaningful kinetic triplet for each of the stages [reaction model f (α), activation energy (Ea) and pre-exponential factor (A)] is reported for multiple layer charges. The first two stages involved removal of water from interlayer and brucite layer respectively, of the material and follows an n-dimensional Avrami-like model. The removal of NOx from interlayer nitrate anion (third stage) follows a 3-dimensional diffusion model of Jander type. The proposed kinetic model is validated by the comparison of the reaction extent (for each of the stages)—both theoretically (chemical formula) and experimentally (from fitting curve) for LDH of multiple layer charges. The isothermal prediction based on the assigned kinetic model predicted the degree of decomposition of LDH with reasonable accuracy.