Synthesis of cross-linked tannin-gelatin hydrogels

Thermal and sorption properties and morphology of cross-linked tannin-gelatin hydrogels obtained in the presence of Fe III ions are studied. Kinetic regularities of swelling of prepared hydrogels in distilled water and buffer solutions were established on the basis of three different models including pseudo-first- and pseudo-second-order kinetic equations. The stability of the hydrogel composites obtained against degradation in a urea solution was studied. Hydrogels containing 2.1 • 10 −4 wt.% FeCl 3 showed the best sorption characteristics. This fact indicates that the most ordered structures with the largest free volume are formed at this content of FeCl 3 .