Characterization and thermal behaviour of tannic acid compounds with Fe(II) and Co(II) in solid state

Tannic acid has been  much insvestigated over the years due to many applications. It can be used in water treatment, in food additive, in pharmaceutical applications and in metallurgical industries. The great variety of the tannic acid`s use is due to the numerous phenol groups in its structure. The behavior between tannic acid and metals was studied for better understanding of its use. Solid state M-L, where M represents bivalent metals (Co, Fe) and L is tannic acid, were prepared by mixture in different molar ratios M:L (1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1) and at pH (3, 5, 8). Simultaneous thermogravimetry and differential thermal analysis (TG - DTA), TG-DSC coupled to FTIR and infrared spectroscopy were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, interaction M-L and thermal decomposition of the isolated compounds.