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

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.