Thermal Analysis Kinetics Of Multi-step Decomposition In The Solid State

Thermal analysis has now had more than eleven decades of history. During this long history, various techniques were invented and thermal analysis has been used in many fields. With fully automated thermo-balances, researchers explored new fields of thermal decomposition. The natural goal of research in this field is kinetic study. Extensive work has been carried out on the non-isothermal decomposition kinetics of solid system. Multiple techniques were reported in literatures for determining the reaction mechanism and deducing kinetic parameters. The present work is aimed at the thermal decomposition process of basic zinc carbonate, cobalt (II) complexes and rice husk. The activation energy for the decomposition was also evaluated. Thermal decomposition of basic zinc carbonate is an essential step for preparation of zinc oxide. The mechanism and kinetics of thermal decomposition of basic zinc carbonate had been reported by several authors. The discrepancy observed in the results reported by different authors would be due to different samples, experimental conditions and kinetic methods. In this study, zinc carbonate hydroxide was prepared by the precipitated method. The thermal behavior and the kinetics of decomposition were studied. The effect of procedural variables on the kinetics was investigated. In this work, the procedural variables included heating rate, sample size and gas environment. The procedural variables can affect the shape of the TG and DTA curves. An increase in the heating rate causes an increase in the peak temperature, and an increase in the peak height. An increase in sample size causes an increase in the reaction temperature, and a decrease in the value of Ea. The decomposed temperatures of TG curves and the peak temperature of DTA curves of decomposition in CO2 are higher than in air. The decomposition of zinc carbonate hydroxide is repressed by CO 2 atmosphere only in some range of degree conversion. Co (NIA)2(H2O)4 and Co(IN)2(H2O)4 are transition metal organic-inorganic composite compounds with the novel three-dimensional supramolecular structure. It displays remarkably a cavity structure and ladder-type hydrogen bond chains. The formation of this special structure is attributed to such a character that it has two carboxylates and four water molecules, which are strong donor/acceptor in hydrogen bond interactions. The present study is concerned with the non-isothermal decomposition of the Co (II) complexes in different atmosphere. Comparing the thermal decomposition in nitrogen and air atmospheres, similar results are obtained for the dehydration process. Activation energy of the second decomposition stage in air is much lower than that in nitrogen. This indicates the accelerated effect of air on the second decomposition reaction stage. In addition, the thermal behaviour of Co (NIA)2(H2O)4 is compared to that of Co(IN)2(H2O)4 in air atmosphere. The different between Co (NIA)2(H2O)4 and Co(IN)2(H2O)4 is that the former has much stronger intermolecular contact and higher symmetry than the latter and leads to higher lattice energy. The prospect of producing clean, sustainable power in substantial quantities from agricultural residues is now arousing interest world-wide, stimulated by increasing concern over the environmental consequences of conventional fossil and nuclear fuel use. Rice husk, as an agricultural residue,...