Kinetics and Mechanism of Non-Isothermal Decomposition of Ca(II)-, Sr(II)- and Ba (II)- Cross-Linked Divalent Metal-Alginate Complexes

Abstract

The kinetics of thermal decomposition of Ca(II)-, Sr(II)-and Ba(II)-cross-linked metal-alginate biopolymeric complexes as biocatalysts have been studied using thermogravimetric (TG) and differential thermogravimetric (DTG) techniques in static air. The TG curves showed three stages of weight loss, whereas the DTG indicated the presence of a series of thermal peaks associated with the TG curves. The thermal dehydration of the coordinated water molecules was found to occur in the first stage, followed by decomposition of the formed dehydrated complexes through the other following stages. The second stage was corresponding to the formation of oxalates as intermediate fragments, whereas the third stage indicated the formation of metal oxides as final product of such decomposition. The kinetic parameters were computed by different models and tentative decomposition mechanism is discussed.

Temperature-Dependence of Electrical Conductivity for Some Natural Coordination Polymeric Biomaterials Especially Some Cross-Linked Trivalent Metal-Alginate Complexes with Correlation between the Coordination Geometry and Complex Stability

“…On other hand, the sharp increase in ơ values observed at elevated temperatures (III) can be explained by the decomposition of the arsenic carbonate to give rise to its corresponding more stable metal oxide as final degradation products [14,15,30,31] [As(OH) 2 …”