Preparation and characterization of chitosan gel beads crosslinked by organic titanium

Chitosan (CTS) gel was successfully prepared by organic titanium(OT) ionic crosslinking agent. The viscoelastic properties of CTS gel was investigated through rheological measurement. The sol-gel transition point (t(cr)) of gel prepared with CTS (22.5 g.L-1) and OT (1.5 %) was determined at 339 s, with the increases of either CTS or OT concentration, the gelation became faster and the sol-gel transition time became shorter. The optimal chitosan gel beads were prepared with 35 g.L-1 chitosan and 7% organic titanium (OT) at room temperature for 1 h reaction. The SEM data indicated that the gel beads had special shape with rough and poriferous surface. The effective grain size range was 1.0-1.2 mm. It was confirmed by TG data that the gel beads performed better in thermal stability than original chitosan. Swelling experiments showed that the swelling ability of gel beads strongly depended on the pH value of buffer solution. On the whole, the modified CTS/OT gel beads showed high adsorption capacity, good mechanical properties, strong acidic and alkali resistances, it could serve as potential drug deliver and the absorbent for heavy metal ions.